1. Introduction
⌅Mountain areas occupy 40,957,238 km2, approximately 30.55% of the global land area. For Kapos (2000)Kapos, V., 2000. UNEP-WCMC Web Site: Mountains and Mountain Forests. Mountain Research and Development, 20: 378. , they are defined according to the slope, elevation and local relief. However, despite these factors being important, the definition of a mountain is not simple. For instance, absolute elevation is not the best criterion. The degree that slope change in space (ruggedness) is also important (UNEP-WMC, 2002UNEP-WMC, 2002. Mountain Watch. Global Environmental Facility, 80 p.). Kapos et al. (2002)Kapos, V. Rhind, J., Edwards, M., Price. M.F. & Ravilious, C., 2002. Developing a map of the world’s mountain forests. In: Forests in Sustainable Mountain Development: A State-of-Knowledge Report for 2000, M.F. Price and N. Butt (eds.), CAB International, Wallingford: 4-9. created criteria to define mountains based on altitude and slope. They divided mountain environments in different classes Class 1: elevation ≥ 4 500 m; Class 2: elevation 3 500-4 500 m; Class 3: elevation 2 500-3 500 m; Class 4: elevation 1 500-2 500 m and slope ≥ 2°; Class 5: elevation 1 000-1 500 m and slope ≥ 5° or LER > 300 m; Class 6: elevation 300-1 000 m and LER > 300 m (Kapos et al., 2002Kapos, V. Rhind, J., Edwards, M., Price. M.F. & Ravilious, C., 2002. Developing a map of the world’s mountain forests. In: Forests in Sustainable Mountain Development: A State-of-Knowledge Report for 2000, M.F. Price and N. Butt (eds.), CAB International, Wallingford: 4-9.; https://www.fao.org/mountain-partnership/about/definitions/en/).
A good discussion about the challenges in the definition of mountain environments was conducted by Körner et al. (2011)Körner, C., Paulsen, J. & Spehn. E.M., 2011. A definition of mountains and their bioclimatic belts for global comparisons of biodiversity data. Alpine Botany, 121: 73. doi.org/10.1007/s00035-011-0094-4 . Elevation cannot be the unique criterion for defining mountains since flat areas (plateaus) are located at altitudes around 2000 m (e.g., Central Asia). Also, mountains cannot be defined only by climate. A similar climate is observed in Antarctic and Arctic lowlands. The most common feature in mountain areas is the steepness and ruggedness (Körner et al., 2011Körner, C., Paulsen, J. & Spehn. E.M., 2011. A definition of mountains and their bioclimatic belts for global comparisons of biodiversity data. Alpine Botany, 121: 73. doi.org/10.1007/s00035-011-0094-4 ). Recently Körner et al. (2021)Körner, C., Urbach, D. & Paulsen, J., 2021. Mountain definitions and their consequences. Alpine Botany, 131: 213-217. doi.org/10.1007/s00035-021-00265-8 discussed the different mountain definitions and their consequences in identifying the area occupied. However, to use a standard definition, we consider a mountain as a “landform that rises prominently above its surroundings, generally exhibiting steep slopes, a relatively confined summit area, and considerable local relief. Mountains generally are understood to be larger than hills, but the term has no standardized geological meaning. Very rarely do mountains occur individually. In most cases, they are found in elongated ranges or chains. When an array of such ranges is linked together, it constitutes a mountain belt” (https://www.britannica.com/science/mountain-landform). Mountain areas play an essential role in shaping climate and the origin of the large majority of rivers. Also, they have an important influence in the surrounding areas through nutrient runoff and biotic interaction. Mountains are also hotspots and cradles for biodiversity and provide many ecosystem services (ES) essential for humans. Between 400-900 million humans live or depend partly or entirely on mountains (Sayre et al., 2018Sayre, R., Frye, C., Karagulle, D., Krauer, J., Aniello, P., Wright, D.J., Payne, D., Adler, C., Warner, H., VanSistine, D.P. & Cress, J., 2018. A New High-Resolution Map of World Mountains and an Online Tool for Visualizing and Comparing Characterizations of Global Mountain Distributions. Mountain Research and Development, 38(3): 240-249. doi.org/10.1659/MRD-JOURNAL-D-17-00107.1 ; Rahbek et al., 2019aRahbek, C., Borregaard, M.K., Antonelli, A., Colwell, R.K., Holt, B.G., Nogués-Bravo, D., Rasmussen, C.M.O., Richardson, K., Rosing, K., Whittaker, R.J. & Fjeldsa, J., 2019a. Building mountain biodiversity: Geological and evolutionary processes. Science, 365 (6458): 1114-1119. doi.org/10.1126/science.aax0151 ; Perrigo et al., 2020Perrigo, A., Hoorn, C. & Antonelli, A., 2020. Why mountains matter for biodiversity. Journal of Biodiversity, 47(3): 315-325. doi.org/10.1111/jbi.13731 ). Although mountains are harsh environments, there are multiple records that they have been occupied since pre-historical times and served as an important source of resources and shelter for the humans in America (e.g., Arkush & Arkush, 2021Arkush, B.S. & Arkush, D., 2020. Aboriginal plant use in the central Rocky Mountains: Macrobotanical records from three prehistoric sites in Birch Creek Valley, eastern Idaho. North American Archeologist, 42: 66-108. doi.org/10.1177/0197693120967005 ), Africa (e.g., Phillips et al., 2019Phillips, N., Pargeter, J., Low, M. & Mackday, A., 2019. Open-air preservation of miniaturised lithics: experimental research in the Cederberg Mountains, southern Africa. Archaeological and Anthropological Sciences, 11: 5851-5877. doi.org/10.1007/s12520-018-0617-7 ), Asia (e.g., Heydari-Guran & Ghasidian, 2020Heydari-Guran, S. & Ghasidian, E., 2020. Late Pleistocene hominin settlement patterns and population dynamics in the Zagros Mountains: Kermanshah region. Archaeological Research in Asia, 21: 100161. doi.org/10.1016/j.ara.2019.100161 ), Europe (e.g., Mazzucco et al., 2019Mazzucco, N., Clemente Conte, I. & Gassiot, E., 2019. Lost in the mountains? The Cova del Sardo and the Neolithisation of the Southern Central Pyrenees (fifth-third mill. cal bc). Archaeological and Anthropological Sciences, 11: 1461-1475. doi.org/10.1007/s12520-018-0603-0 ), and Oceania (Slack et al., 2018Slack, M.J., Law, W.B. & Gliganic, L.A., 2018. Pleistocene settlement of the eastern Hamersley Plateau: A regional study of 22 rock-shelter sites. Archeology in Oceania, 53(3): 191-204. doi.org/10.1002/arco.5163 ). In several mountain areas, humans developed strategies to adapt to rough environments (e.g., terraces) (e.g., Lasanta et al., 2017Lasanta, T., Arnáez, J., Pascual, N., Ruiz-Flaño, P., Errea, M.P. & Lana-Renault, N., 2017. Space-time process and drivers of land abandonment in Europe. Catena, 149: 810-823. https://doi.org/10.1016/j.catena.2016.02.024 ).
It is well known that, mountains provide a multitude of ES (e.g., carbon sequestration, air quality purification, water provisioning, food, recreation) (e.g., Grêt-Regamey et al., 2012Grêt-Regamey, A., Hanna Brunner, S. & Kienast, F., 2012. Mountain Ecosystem Services: Who Cares? Mountain Research Development, 32: S1. doi.org/10.1659/MRD-JOURNAL-D-10-00115.S1 ; Liu et al., 2019Liu, L., Wang, Z., Wang, Y., Zhang, Y., Shen, J., Qin, D. & Li, S., 2019. Trade-off analyses of multiple mountain ecosystem services along elevation, vegetation cover and precipitation gradients: A case study in the Taihang Mountains. Ecological Indicators, 103: 94-104. doi.org/10.1016/j.ecolind.2019.03.034 ; Grêt-Regamey & Weibel, 2020Grêt-Regamey, A. & Weibel, B., 2020. Global assessment of mountain ecosystem services using earth observation data. Ecosystem Services, 46: 101213. doi.org/10.1016/j.ecoser.2020.101213 ). However, they are among the most fragile ecosystems, and several reports highlighted that they are extremely vulnerable to climate change (e.g., Iglesias et al., 2018Iglesias, V., Whitlock, C., Krause, T.R. & Baker, R.G., 2018. Past vegetation dynamics in the Yellowstone region highlight the vulnerability of mountain systems to climate change. Journal of Biogeography, 45(8): 1768-1780. doi.org/10.1111/jbi.13364 ). Some biophysical systems started a process of adaptation, as highlighted in Vij et al. (2021)Vij, S., Biesbroek, R., Adler, C. & Muccione, V., 2021. Climate Change Adaptation in European Mountain Systems: A Systematic Mapping of Academic Research. Mountain Research Development, 41(1): A1-A6. doi.org/10.1659/MRD-JOURNAL-D-20-00033.1 . For instance, according to the latest IPCC (2021)IPCC, 2021. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press. report, mountain glaciers retreat has been unprecedented in the last 2000 years. Also, the changes in snow cover and the earlier onset of spring melt is changing rivers streamflow seasonality, ecosystem dynamics and water supply in low altitude areas. Permafrost and mountain glaciers are expected to melt for decades or hundreds of years. The permafrost degradation and glacier melting in mountain areas increase slopes instability, and the formation of glacial lakes increases the risk of landslides and glacial lakes outburst floods. Precipitation extremes are expected to rise in all the scenarios in mountain regions, triggering floods and landslides. The temperature changes are also expected to affect mountain habitats, and in recent decades a tremendous change in species abundance and composition has been identified.
Human pressures in mountains and profound socio-economic changes are affecting ecosystems equilibrium. Activities such as mining (e.g., Bokar et al., 2020Bokar, H., Traoré, A.Z., Mariko, A., Diallo, T., Traoré, A., Sy, A., Soumaré, O., Dolo, A., Bamba, F., Sacko, M. & Toure, O., 2020. Geogenic influence and impact of mining activities on water soil and plants in surrounding areas of Morila Mine, Mali. Journal of Geochemical Exploration, 209: 106429. doi.org/10.1016/j.gexplo.2019.106429 ), massive tourism (e.g., Nepal et al., 2020Nepal, P., Khanal, N.R., Zhang, Y., Paudel, B. & Liu, L., 2020. Land use policies in Nepal: An overview. Land Degradation and Development, 31(16): 2203-2212. doi.org/10.1002/ldr.3621 ), intensive agriculture expansion (e.g., Peters et al., 2019Peters, M.K., Hemp, H., Appelhans, T., Becker, J.N., Behler, C., Classen, A., Detsch, F., Ensslin, A., Ferger, S.W., Frederiksen, S.B., Gebert, F.G., Gerschlauer, F., Gütlein, A., Helbig-Bonitz, M., Hemp, C., Kindeketa, W.J., Kühnel, A., Mayr, A.V., Mwangomo, E., Ngereza, C., Njovu, H.K., Otte, I., Pabst, H., Renner, M., Röder, J., Rutten, G., Schellenberger Costa, D., Sierra-Cornejo, N., Vollstädt, M.G.R., Dulle, H.I., Eardley, C.D., Howell, K.M., Keller, A.K., Peters, R.S., Ssymank, A.S., Kakengi, V., Zhang, J., Bogner, C., Böhning-Gaese, K., Brandl, R., Hertel, D., Huwe, B., Kiese, R., Kleyer, M., Kuzyakov, Y., Nauss, T., Schleuning, M., Tschapka, M., Fischer, M. & Steffan-Dewenter, I., 2019. Climate-land-use interactions shape tropical mountain biodiversity and ecosystem functions. Nature, 568: 88-92. doi.org/10.1038/s41586-019-1048-z ) have a dramatic impact on the ecosystems. On the other hand, mountain areas are suffering from rural exodus in several regions of the world. The abandonment of these areas is changing unprecedently semi-natural habitats created by millennial human activities. Although some benefits from this dynamic are recognised (e.g., rewilding, biodiversity conservation), negative implications occur as well (e.g., loss of semi-natural grassland ecosystems, wildfire risk increase) (e.g., Hinojosa et al., 2019Hinojosa, L., Tasser, E., Rüdisser, J., Leitinger, G., Schermer, M., Lambin, E.F. & Tappeiner, U., 2019. Geographical heterogeneity in mountain grasslands dynamics in the Austrian-Italian Tyrol region. Applied Geography, 106: 50-59. doi.org/10.1016/j.apgeog.2019.03.006 ; García-Ruiz et al., 2020García-Ruiz, J.M., Lasanta, T., Nadal-Romero, E., Lana-Renault, N. & Álvarez-Farizo, B., 2020. Rewilding and restoring cultural landscapes in Mediterranean mountains: Opportunities and challenges. Land Use Policy, 99: 104850. doi.org/10.1016/j.landusepol.2020.104850 ). These socio-economic and environmental changes have a substantial implication on ES supply (Pereira, 2020Pereira, P., 2020. Ecosystem services in a changing environment. Science of the Total Environment, 702: 135008. doi.org/10.1016/j.scitotenv.2019.135008 ). Therefore, it is critical to understand and identify the biotic and abiotic ES supplied by mountain areas and the drivers of change that can affect their quantity and quality. This perspective article aims to assess the regulating, provisioning and cultural ES supplied in mountain areas and the effects of a changing environment.
2. Regulating Ecosystem Services
⌅Mountains have a different climate from the surrounding land. The altitude and the complex topography affect weather, climate, plant and animal distribution, even at small scales (e.g., Jähnig et al., 2020Jähnig. S., Sander, M.M., Caprio, E., Rosselli, D., Rolando, A. & Chamberlain, D., 2020. Microclimate affects the distribution of grassland birds, but not forest birds, in an Alpine environment. Journal of Ornithology, 161: 677-689. doi.org/10.1007/s10336-020-01778-5 ). Therefore, the biodiversity in these environments is high when compared to lowland areas. Even though mountains occupy approximately 30% of the terrestrial area, they host more than 85% of the diversity of mammals, birds and amphibians (Rahbek et al., 2019bRahbek, C., Borregaard, M.K., Colwell, R.K., Dalsgaard, B., Holt, B.G., Morueta-Holme, N., Nogués-Bravo, D., Whittaker, R.J. & Fjeldsa, J., 2019b. Humboldt’s enigma: What causes global patterns of mountain biodiversity? Science, 365 (6458), 1108-1113. doi.org/10.1126/science.aax0149 ). This high biodiversity is only possible due to the habitat’s quality and the presence of well preserved and forests. Several works found that mountain forests have a high capacity for carbon sequestration (global and local climate regulation) (e.g., Sil et al., 2017Sil, A., Fonseca, F., Goncalves, J., Honrado, J., Marta-Pedroso, C., Alonso, J., Ramos, M., & Azevedo, J.C., 2017. Analyzing carbon sequestration and storage dynamics in a changing mountain landscape in Portugal: insights for management and planning. International Journal of Biodiversity Science, Ecosystem Services & Management, 13: 82-104. doi.org/10.1080/21513732.2017.1297331 ; Stritih et al., 2021Stritih, A., Bebi, P., Rossi, C. & Grêt-Regamey, A., 2021. Addressing disturbance risk to mountain forest ecosystem services. Journal of Environmental Management, 296: 113188. doi.org/10.1016/j.jenvman.2021.113188 ) (Figure 1), and this can be different according to the slope aspect. For instance, Swetnam et al. (2017)Swetnam, T.L., Brooks, P.D., Barnard, H.R., Harpold, A.A., Gallo, E., 2017. Topographically driven differences in energy and water constrain climatic control on forest carbon sequestration. Ecosphere 8, e01797. https://doi.org/10.1002/ecs2.1797 found that in the Rocky Mountains (The USA), the carbon storage capacity was higher in the north-facing slopes than in the southern. Similar results were also identified by Fravolini et al. (2018)Fravolini, G., Tognetti, R., Lombardi, L., Egli, M., Ascher-Jenull, J., Arfaioli, P., Bardelli, T., Cherubini, P. & Marchetti, M., 2018. Quantifying decay progression of deadwood in Mediterranean mountain forests. Forest Ecology and Management, 408: 228-237. doi.org/10.1016/j.foreco.2017.10.031 in the Mediterranean mountains. These differences can also be identified in different mountain ecosystems. For example, forests have a higher capacity than grasslands to store carbon (Yu et al., 2020Yu, Y., Li, J., Zhou, Z., Zeng, L. & Zhang, C., 2020. Estimation of the Value of Ecosystem Carbon Sequestration Services under Different Scenarios in the Central China (the Qinling-Daba Mountain Area). Sustainability, 12: 337. doi.org/10.3390/su12010337 ). Others found that the implementation of measures that reduce fire risk and increase biodiversity in mountain areas of Gerês-Xurés (Portugal and Spain) would be key for carbon sequestration in the long term (Pais et al., 2020Pais, S., Aquilué, N., Campos, J., Sil, A., Marcos, B., Martínez-Freiría, F., Domínguez, J., Brotons, L., Honrado, J.P. & Regos, A., 2020. Mountain farmland protection and fire-smart management jointly reduce fire hazard and enhance biodiversity and carbon sequestration. Ecosystem Services, 44: 10113. doi.org/10.1016/j.ecoser.2020.101143 ). On the other hand, Seidl et al. (2019)Seidl, R., Albrich, K., Erb, K., Formayer, H., Leidinger, D., Leitinger, G., Tappeiner, U., Tasser, E. & Rammer, W., 2019. What drives the future supply of regulating ecosystem services in a mountain forest landscape? Forest Ecology and Management, 445: 37-47. doi.org/10.1016/j.foreco.2019.03.047 identified that unmanaged forests in the Alps have a high capacity for carbon sequestration and, therefore, climate regulation. Mountains with high biodiversity and forest cover have a high capacity for local and global climate regulation.
Vegetation can capture particulate matter (10 and 2.5 mm) and pollutants from the atmosphere (Pereira et al., 2022Pereira, I., Inacio, M., Karnauskaite, D., Bogdzevič, K., Gomes, E. & Kalinauskas, M., 2022. Nature-Based Solutions Impact on Urban Environment Chemistry: Air, Soil, and Water. In: Ferreira, C.S.S., Kalantari, Z., Hartmann, T., Pereira, P. (eds) Nature-Based Solutions for Flood Mitigation. Environmental and Socio-Economic Aspects. Springer, Berlin, Heidelberg. https://doi.org/10.1007/698_2021_760 ) (Figure 1). Therefore it is expected that forest mountain areas located near cities can reduce air pollution. Most of the studies carried out were focused on urban trees or urban forests (e.g., Yli-Pelkonen et al., 2017Yli-Pelkonen, V., Setälä, H. & Viippola, V., 2017. Urban forests near roads do not reduce gaseous air pollutant concentrations but have an impact on particles levels. Landscape and Urban Planning, 158: 39-47. doi.org/10.1016/j.landurbplan.2016.09.014 ; Nowak et al., 2018Nowak, D.J., Hirabayashi, S., Doyle, M., McGovern, M. & Pasher, J., 2018. Air pollution removal by urban forests in Canada and its effect on air quality and human health. Urban Forestry & Urban Greening, 29: 40-48. doi.org/10.1016/j.ufug.2017.10.019 ). Few studies were conducted in green areas located in mountain environments using measured data or models (Mengist et al., 2020Mengist, W., Soromessa, T. & Legese, G., 2020. Ecosystem services research in mountainous regions: A systematicliterature review on current knowledge and research gaps. Science of the Total Environment, 702, 134581. doi.org/10.1016/j.scitotenv.2019.134581 ). However, Ji-Young et al. (2017)Ji-Young, E., Hee, J.S. & Lee, J.S., 2017. Assessment of absorption ability of air pollutant on forest in Gongju-city. Journal of Ecology and Environment, 41: 328-335. doi.org/10.1186/s41610-017-0058-8 found that in the Gongju City (Korea), the surrounding forests located had a high capacity to capture pollutants. Evergreen coniferous had a high capacity to remove pollutants than evergreen forests. More studies have been developed about the social perception of the role of mountain forests in air purification. However, the results are not conclusive, and some showed that this ES is highly valued (e.g., He et al., 2018He, S., Gallagher, L., Su, Y., Wang, L. & Cheng, H., 2018. Identification and assessment of ecosystem services for protected area planning: A case in rural communities of Wuyishan national park pilot. Ecosystem Services, 31: 169-180. https://doi.org/10.1016/j.ecoser.2018.04.001 ; Pedraza et al., 2020Pedraza, S., Sanchez, A., Clerci, N., Ospina, L., Quintero, A. & Escobedo, F,J., 2020. Perception of conservation strategies and nature’s contributions to people around Chingaza National Natural Park, Colombia. Environmental Conservation, 47: 158-165. doi:10.1017/S037689292000020X ), while others are not (Paudyal et al., 2018Paudyal, K., Baral, H. & John Keenan, R., 2018. Assessing social values of ecosystem services in the Phewa Lake Watershed, Nepal. Forest Policy and Economics, 90: 67-81. doi.org/10.1016/j.forpol.2018.01.011 ).
Mountain forests can filter and regulate water flow (e.g., Locatelli et al., 2017Locatelli, B., Lavorel, S., Sloan, S., Tappeiner, U. & Geneletti, D., 2017. Characteristic trajectories of ecosystem services in mountains. Frontiers in Ecology and the Environment, 15: 150-159. doi.org/10.1002/fee.1470 ; Ngwenya et al., 2019Ngwenya, S.J., Torquebiau, E. & Ferguson, J.W.H., 2019. Mountains as a critical source of ecosystem services: the case of the Drakensberg, South Africa. Environment Development and Sustainability, 21: 1035-1052. doi.org/10.1007/s10668-017-0071-1 ; Ma et al., 2021Ma, D., Zhou, J., Li, Q., Dou, J., Huang, J., Zhu, G., Wang, L. & Hu, K., 2021. Temporal Variations of Hydrochemical Characteristics and Their Controlling Factors in the Xiying River Basin in the Eastern Qilian Mountains, China. Polish Journal of Environmental Studies, 30: 3741-3751. doi.org/10.15244/pjoes/131948 ), controlling the water quality and quantity that reach the water bodies (Figure 1). They reduce the sediment transport significantly and sustain the fragile mountain soils. Forests are a key for mountains soil conservation, as observed in several works (e.g., Sheng et al., 2017Sheng, W., Zhen, L., Xie, G. & Xiao, Y., 2017. Determining eco-compensation standards based on the ecosystem services value of the mountain ecological forests in Beijing, China. Ecosystem Services, 26: 422-430. doi.org/10.1016/j.ecoser.2017.04.016 ; Xiao et al., 2017Xiao, Q., Hu, D. & Xiao, Y., 2017. Assessing changes in soil conservation ecosystem services and causal factors in the Three Gorges Reservoir region of China. Journal of Cleaner Production, 163: S172-S180. doi.org/10.1016/j.jclepro.2016.09.012 ). This high capacity to retain water and regulate flow is key to reducing peak flow and decreasing the probability of flash floods and landslides after high-intensity precipitation events (e.g., Paudyal et al., 2018Paudyal, K., Baral, H. & John Keenan, R., 2018. Assessing social values of ecosystem services in the Phewa Lake Watershed, Nepal. Forest Policy and Economics, 90: 67-81. doi.org/10.1016/j.forpol.2018.01.011 ; Costache et al., 2020Costache, R., Hong, H. & Bao Pham, Q., 2020. Comparative assessment of the flash-flood potential within small mountain catchments using bivariate statistics and their novel hybrid integration with machine learning models. Science of the Total Environment, 711: 134514. doi.org/10.1016/j.scitotenv.2019.134514 ; Huber et al., 2020Huber, L., Schirpke, U., Marsoner, T., Tasser, E. & Leitinger, G., 2020. Does socioeconomic diversification enhance multifunctionality of mountain landscapes? Ecosystem Services, 44: 101122. doi.org/10.1016/j.ecoser.2020.101122 ). Forested catchments can reduce the flood peak from 3 to 70%, especially in small and medium-sized floods (Wahren et al., 2012Wahren, A., Schwärzel, K. & Feger, K.-H. 2012. Potentials and limitations of natural flood retention by forested land in headwater catchments: evidence from experimental and model studies. Journal of Flood Risk Management, 5: 321-335. Doi: 10.1111/j.1753-318X.2012.01152.x ). Also, in natural forests, surface microrelief contributes to increasing water retention and decreasing runoff (Valtera & Schaetzl, 2017Valtera, M. & Schaetzl, R.J., 2017. Pit-mound microrelief in forest soils: Review of implications for water retention and hydrologic modelling. Forest Ecology and Management, 393: 40-51. doi.org/10.1016/j.foreco.2017.02.048 ). Mountain areas are also known to host a high diversity of pollinators (e.g., Naeem et al., 2020Naem, M., Huang, J., Zhang, S., Luo, S., Liu, Y., Zhang, H., Luo, Q., Zhou, Z., Ding, G., & An, J., 2020. Diagnostic indicators of wild pollinators for biodiversity monitoring in long-term conservation. Science of the Total Environment, 708: 135231. doi.org/10.1016/j.scitotenv.2019.135231 ; Baumann et al., 2021Baumann, K., Keune, J., Wolters, V. & Jauker, F. 2021. Distribution and pollination services of wild bees and hoverflies along an altitudinal gradient in mountain hay meadows. Ecology and Evolution, 11: 11345-11351. doi.org/10.1002/ece3.7924 ), essential to agricultural production and the function of rural communities.
3. Ecosystem Services Provisioning
⌅Mountain supply a vast array of food, such as mushrooms, cash crops, berries, vegetables, spices and medicinal plants (McLellan & Brown, 2017McLellan, T. & Brown, M., 2017. Mushrooms and Cash Crops Can Coexist in Mountain Livelihoods: Wild Mushrooms as Economic and Recreational Resources in the Greater Mekong. Mountain Research and Development, 37: 108-120. doi.org/10.1659/MRD-JOURNAL-D-15-00087.1 ; Ulloa-Muñoz et al., 2020Ulloa-Muñoz, R., Olivera-Gonzales, Castañeda-Barreto, A., Villena, G.K. & Tamariz-Angeles, C., 2020. Diversity of endophytic plant-growth microorganisms from Gentianella weberbaueri and Valeriana pyenantha, highland Peruvian medicinal plants. Microbiological Research, 233: 126413. doi.org/10.1016/j.micres.2020.126413 ) (Figure 1). Other animal-based products are produced from these areas, such as meat, oils, fats, milk, cheese, fish, and shellfish (Martins & Ferreira, 2017Martins, N. & Ferreira, I.C.F.R., 2017. Mountain food products: A broad spectrum of market potential to be exploited. Trends in Food Science & Technology, 67: 12-18. doi.org/10.1016/j.tifs.2017.06.013 ). Numerous works highlight the high capacity of mountain areas for crops, livestock, wild food, and fish supply (e.g., Kokkoris et al., 2018Kokkoris, I.P., Drakou, E.G., Maes, J. & Dimopoulos, P., 2018. Ecosystem services supply in protected mountains of Greece: setting the baseline for conservation management. International Journal of Biodiversity Science, Ecosystem Services & Management, 14: 45-59. doi.org/10.1080/21513732.2017.1415974 ; Faccione et al., 2019Faccione, G., Sturaro, E., Ramanzin, M. & Bernués, A., 2019. Socio-economic valuation of abandonment and intensification of Alpine agroecosystems and associated ecosystem services. Land Use Policy, 83: 453-462. doi.org/10.1016/j.landusepol.2018.10.044 ). Also, they provide a basic income to mountain communities as observed elsewhere (e.g., Shrestha et al., 2019Shrestha, U.B., Dhital, K.B. & Gautam, A.P., 2019. Economic dependence of mountain communities on Chinese caterpillar fungus Ophiocordyceps sinensis (yarsagumba): a case from western Nepal. Oryx, 53: 256-264. doi.org/10.1017/S0030605317000461 ). Due to the high diversity and food quality, several certification schemes were developed to label mountain regional products and increase consumer trust. This is key to improving mountain rural areas’ livelihood and sustainability (Mazzocchi & Sali, 2022Mazzocchi, C. & Sali, G., 2022. Supporting mountain agriculture through “mountain product” label: a choice experiment approach. Environment, Development and Sustainability, 24: 701-723. doi.org/10.1007/s10668-021-01464-3 ). Timber and biomass for energy are also important ES supplied by mountains (e.g., Gurung et al., 2021Gurung, L.J., Miller, K.K., Venn, S. & Bryan, B.A., 2021. Contributions of non-timber forest products to people in mountain ecosystems and impacts of recent climate change. Ecosystems and People, 17: 447-463. doi.org/10.1080/26395916.2021.1957021 ) (Figure 1). In several areas is still one of the most important sources of local communities’ income and is highly valued in the Alps (Gori et al., 2018Gori, Y., Stradiotti, A. & Camin, F., 2018. Timber isoscapes. A case study in a mountain area in the Italian Alps. PlosOne, 13: e0192970. doi.org/10.1371/journal.pone.0192970 ), Carpathians (Melnykovych et al., 2018Melnykovych, M., Nijnik, M., Soloviy, I., Nijnik, A., Sarkki, S. & Bihun, Y., 2018. Social-ecological innovation in remote mountain areas: Adaptive responses of forest-dependent communities to the challenges of a changing world. Science of the Total Environment, 613-614: 894-906. doi.org/10.1016/j.scitotenv.2017.07.065 ), Himalayas (Gentle & Marseni, 2012Gentle, P. & Maraseni, T.N., 2012. Climate change, poverty and livelihoods: adaptation practices by rural mountain communities in Nepal. Environmental Science & Policy, 21: 24-34. doi.org/10.1016/j.envsci.2012.03.007 ) and Africa - Burundi (Ndayizeye et al., 2020Ndayizeye, G., Imani, G., Nkengurutse, J., Irampagarikiye, R., Ndihokubwayo, N., Niyongabo, F. & Cuni-Sanchez, A., 2020. Ecosystem services from mountain forests: Local communities’ views in Kibira National Park, Burundi. Ecosystem Services, 45: 101171. doi.org/10.1016/j.ecoser.2020.101171 ). Mountains are environments that have the highest capacity to provide freshwater. They act as natural water towers and supply approximately 60 to 80% of world freshwater (https://www.fao.org/mountain-partnership/our-work/focusareas/water/en/). Mountains as water towers are critical in semi-arid and arid areas and have an essential role in supplying water for agriculture, industry, and the growing urban population (Viviroli & Weingartner, 2008Viviroli D. & Weingartner R., 2008. “Water Towers”-A Global View of the Hydrological Importance of Mountains. In: Wiegandt E. (eds): Mountains: Sources of Water, Sources of Knowledge. Advances in Global Change Research, vol. 31. Springer, Dordrecht. doi.org/10.1007/978-1-4020-6748-8_2 ). For instance, approximately 1.5 billion people living in lowlands depend on mountain freshwater (Viviroli et al., 2020Viviroli, D., Kummu, M., Meybeck, M., Kallio, M. & Wada, Y., 2020. Increasing dependence of lowland populations on mountain water resources. Nature Sustainability, 3: 917-928. doi.org/10.1038/s41893-020-0559-9 ).
The high presence of water and sloped terrain make mountains key environments for producing hydropower energy. Since ancestral times, humans used water energy (e.g., water mill) to mill cereals and represented an important energy source for rural communities (e.g., Serrano & González-Amuchastegui, 2020Serrano, E. & González-Amuchastegui, M.J., 2020. Cultural Heritage, Landforms, and Integrated Territorial Heritage: the Close Relationship Between Tufas, Cultural Remains, and Landscape in the Upper Ebro Basin (Cantabrian Mountains, Spain). Geoheritage, 12: 86. https://doi.org/10.1007/s12371-020-00513-z ) (Figure 1). Nowadays, hydropower supplies more than 16% of the total electricity production. This energy type is the primary renewable energy resource and is expected to increase in the future (Bilgili et al., 2018Bilgili, M., Bilirgen, H., Ozbeck, F. & Demirdelen, T., 2018. The role of hydropower installations for sustainable energy development in Turkey and the world. Renewable Energy, 126: 755-764. doi.org/10.1016/j.renene.2018.03.089 ; IEA, 2019IEA (2019), Renewables 2019, IEA, Paris https://www.iea.org/reports/renewables-2019 ). Mountains also have a high potential to supply wind energy. The wind blows with high velocity in high altitude and high roughness areas (e.g., mountain corridors), therefore, several wind farms were established (e.g., Ólafsdóttir & Sæþórsdóttir, 2019Ólafsdóttir, R. & Sæþórsdóttir, A.D., 2019. Wind farms in the Icelandic highlands: Attitudes of local residents and tourism service providers. Land Use Policy, 88: 104173. doi.org/10.1016/j.landusepol.2019.104173 ; Cunden et al., 2020Cunden, T.S.M., Doorga, J., Lollchund, M.R. & Rughooputh, S.D.D.V., 2020. Multi-level constraints wind farms siting for a complex terrain in a tropical region using MCDM approach coupled with GIS. Energy, 211: 118533. doi.org/10.1016/j.energy.2020.118533 ) (Figure 1). After hydropower, wind energy is the energy that contributes the most to renewables production (IEA, 2019IEA (2019), Renewables 2019, IEA, Paris https://www.iea.org/reports/renewables-2019 ). Several projects have been developed in mountain areas to produce solar energy (e.g., Karpić et al., 2019Karpić, J., Sharma, E., Khatib, T. & Elmenreich, W., 2019. Comparison of solar power measurements in alpine areas using a mobile dual-axis tracking system. Energy Informatics, 2: 23. doi.org/10.1186/s42162-019-0091-1 ; Kahl et al., 2019Kahl, A., Dujardin, J. & Lehning, M., 2019. The bright side of PV production in snow-covered mountains. Proceedings of the National Academy of Sciences, 116: 1162-1167. doi.org/10.1073/pnas.1720808116 ), which are an option to be considered in the context of the rising energy demand. For instance, solar energy production in the mountains can be 20% higher than at sea level (https://www.fao.org/mountain-partnership/our-work/focusareas/renewableenergy/en/). Solar energy is the highest contributor to renewables production after hydropower and wind energy (IEA, 2019IEA (2019), Renewables 2019, IEA, Paris https://www.iea.org/reports/renewables-2019 ) (Figure 1). Finally, in mountainous volcanic areas, there is a great potential for the production of geothermal energy (Figure 1). Worldwide, there are several areas where this type of energy is extensively explored, such as in Iceland (e.g., Spittler et al., 2020Spittler, N., Davidsdottir, B., Shafiei, E., Leaver, J., Asgeirsson, E.I. & Stefansson, H., 2020. The role of geothermal resources in sustainable power system planning in Iceland. Renewable Energy, 153: 1081-1090. doi.org/10.1016/j.renene.2020.02.046 ), New Zealand (e.g., Kumar et al., 2021Kumar, P.C., Alves, T.M. & Sain, K., 2021. Forced folding in the Kora Volcanic Complex, New Zealand: A case study with relevance to the production of hydrocarbons and geothermal energy. Geothermics, 89: 101965. doi.org/10.1016/j.geothermics.2020.101965 ), United States (e.g., Neves et al., 2021Neves, R., Cho, H. & Zhang, J., 2021. State of the nation: Customizing energy and finances for geothermal technology in the United States residential sector. Renewable and Sustainable Energy Reviews, 137: 110463. doi.org/10.1016/j.rser.2020.110463 ), Japan (Taghizadeh-Hesary et al., 2020Taghizadeh-Hesary, F., Mortha, A., Farabi-Asl, H., Sarker, T., Chapman, A., Shigetomi, Y. & Fraser, T., 2020. Role of energy finance in geothermal power development in Japan. International Review of Economics & Finance, 70: 398-412. doi.org/10.1016/j.iref.2020.06.011 ) and Italy (Pellizzone et al., 2017Pellizzone, A., Allansdottir, A., De Franco, R., Muttoni, G. & Manzella, A., 2017. Geothermal energy and the public: A case study on deliberative citizens’ engagement in central Italy. Energy Policy, 101: 561-570. doi.org/10.1016/j.enpol.2016.11.013 ). There is an increasing trend of geothermal exploitation (https://www.irena.org/geothermal). Geothermal energy, after hydropower, wind energy and solar energy, is the one that contributes more to the total renewable energy production (IEA, 2019IEA (2019), Renewables 2019, IEA, Paris https://www.iea.org/reports/renewables-2019 ).
Since historical times, mountain areas have been an essential source of mineral resources such as bronze, iron and gold (e.g., Mariet et al., 2018Mariet, A.L., Walter-Simonnet, A.V., Gimbert, F., Cloquet, C. & Bégeot, C., 2018. High-temporal resolution landscape changes related to anthropogenic activities over the past millennium in the Vosges Mountains (France). Ambio, 47: 893-907. doi.org/10.1007/s13280-018-1044-9 ; Tolksdorf et al., 2020Tolksdorf, J.F., Schröder, F., Petr, L., Herbig, C., Kaiser, K., Kočár, P., Fülling, A., Heinrich, S., Hönig, H. & Hemker, C., 2020. Evidence for Bronze Age and Medieval tin placer mining in the Erzgebirge mountains, Saxony (Germany). Geoarcheology, 35: 198-216. doi.org/10.1002/gea.21763 ) (Figure 1). More recently, other vital minerals were exploited in the mountains, which are the primary resources for many countries such as diamonds, coal and other raw materials (e.g., Lithium, Tungsten, Cobalt) (e.g., Redondo-Vega et al., 2017Redondo-Vega, J.M., Gómez-Villar, A., Santos-González, J., González-Gutiérrez, R.B., Álvarez-Martínez, J., 2017. Changes in land use due to mining in the north-western mountains of Spain during the previous 50 years. Catena, 149: 844-856. https://doi.org/10.1016/j.catena.2016.03.017 ; Ahiakwo et al., 2018Ahiakwo, N.I., Egwuonwu, A.C. & Okeke, O.C., 2018. A review of the geology and mineral resources of South Africa. International Journal of Advanced Academic Research, 4: 90-121. ; He et al., 2020He, M.Y., Luo, C.G., Yang, H.J., Kong, F.C., Li, Y.L., Deng, L., Zhang, X. & Yang, K.Y., 2020. Sources and a proposal for comprehensive exploitation of lithium brine deposits in the Qaidam Basin on the northern Tibetan Plateau, China: Evidence from Li isotopes. Ore Geology Reviews, 117: 103277. doi.org/10.1016/j.oregeorev.2019.103277 ). According to OECD (2015)OECD (2015) Material Resources, Productivity and the Environment. OECD, 13 pp. , due to human demand, mineral resources are expected to increase.
4. Cultural Ecosystem Services
⌅Mountains are essential areas for recreation and tourism during the different seasons and attract between 15 to 20% of global tourists (https://www.fao.org/mountain-partnership/our-work/focusareas/sustainable-tourism/en/). These activities are vital to the economy of several communities is expected to increase in the future (World Tourism Organization, 2018World Tourism Organization, 2018. Sustainable Mountain Tourism - Opportunities for Local Communities, Executive Summary, UNWTO, Madrid. doi.org/10.18111/9789284420285 ). For instance, mountains during the winter have a high capacity for skiing activities (e.g., snowboard, skating) during the winter and walking, trekking, biking, rock climbing, paragliding, rafting in spring, summer and autumn (e.g., Mutana & Mukwada 2018Mutana, S. & Mukwada, G., 2018. Mountain-route tourism and sustainability. A discourse analysis of literature and possible future research. Journal of Outdoor Recreation and Tourism, 24: 59-65. doi.org/10.1016/j.jort.2018.08.003 ; Noome & Fitchett, 2019Noome, K., Fitchett, J.M., 2019. An assessment of the climatic suitability of Afriski Mountain Resort for outdoor tourism using the Tourism Climate Index (TCI). Journal of Mountain Science, 16: 2453-2469. doi.org/10.1007/s11629-019-5725-z ) (Figure 1). In several mountain environments (e.g., Pyrenees), it is also popular to pick berries and mushrooms (e.g., Melnykovych et al., 2018Melnykovych, M., Nijnik, M., Soloviy, I., Nijnik, A., Sarkki, S. & Bihun, Y., 2018. Social-ecological innovation in remote mountain areas: Adaptive responses of forest-dependent communities to the challenges of a changing world. Science of the Total Environment, 613-614: 894-906. doi.org/10.1016/j.scitotenv.2017.07.065 ; Fuste-Forne, 2020Fuste-Forne, F., 2020. Seasonality in food tourism: wild foods in peripheral areas. Tourism Geographies, doi.org/10.1080/14616688.2018.1558453 ). Mountain areas are also well known for their high landscape aesthetic value (Hermes et al., 2018Hermes, J., Albert, C. & von Haaren, C., 2018. Assessing the aesthetic quality of landscapes in Germany. Ecosystem Services, 31: 296-307. doi.org/10.1016/j.ecoser.2018.02.015 ) and are a popular place for sight-seeing, photography or wild animal watching (e.g., Larm et al., 2018Larm, M., Elmhagen, B., Granquist, S.M., Brundin, E. & Angerbjörn, A., 2018. The role of wildlife tourism in conservation of endangered species: Implications of safari tourism for conservation of the Arctic fox in Sweden. Human Dimensions of Wildlife, 23: 257-272. doi.org/10.1080/10871209.2017.1414336 ; Ito, 2021Ito, E., 2021. Understanding Cultural Variations in Outdoor Tourism Behaviours for Outdoor Sport Tourism Development: A Case of the Blue Mountains National Park. Tourism Planning and Development, 18: 371-377. doi.org/10.1080/21568316.2020.1807401 ) (Figure 1). For instance, several mountain areas are considered sacred areas for many indigenous cultures in the Himalayas (Brandt et al., 2013Brandt, J.S., Wood, E.M., Pidgeon, A.M., Han, L.X., Fang, Z. & Radeloff, V.C., 2013. Sacred forests are keystone structures for forest bird conservation in southwest China’s Himalayan Mountains. Biological Conservation, 166: 34-42. doi.org/10.1016/j.biocon.2013.06.014 ), Andean (Reinhard, 1985Reinhard, J., 1985. Sacred Mountains: An Ethno-Archaeological Study of High Andean Ruins. Mountain Research and Development, 5: 299-317. doi.org/10.2307/3673292 ), Mongolia (Sneath, 2014Sneath, D., 2014. Nationalising civilisational resources: sacred mountains and cosmopolitical ritual in Mongolia. Asian ethnicity, 15: 458-472. doi.org/10.1080/14631369.2014.939330 ), Japan (McGuire, 2013McGuire, M.P., 2013. What’s at Stake in Designating Japan’s Sacred Mountains as UNESCO World Heritage Sites? Shugendo Practices in the Kii Peninsula. Japanese Journal of Religious Studies, 40: 323-354. ), North America (Shipek, 1985Shipek, F.C., 1985. KUUCHAMAA: The Kumeyaay Sacred Mountain. Journal of California and Great Basin Anthropology, 7: 67-74. ) and Norway (Myrvoll, 2017Myrvoll M., 2017. Gosa Bássi Várit Leat Jávkan? Where Have All The Sacred Mountains Gone?. In: Heinämäki L., Herrmann T. (eds) Experiencing and Protecting Sacred Natural Sites of Sámi and other Indigenous Peoples. Springer Polar Sciences. pp. 101-116. Springer, Cham. https://doi.org/10.1007/978-3-319-48069-5_7 ), therefore with a very high value for spirituality. Since ancestral times, for protection or the abundance of resources, numerous civilizations were developed in mountain areas, some of them reaching a high stage of development (e.g., Incas) (e.g., Gonzales & Bauer, 2021Gonzales, D.A., & Bauer, B.S., 2021. The Ancient Inca Town Named Huayna Picchu. Ñawpa Pacha. doi.org/10.1080/00776297.2021.1949833 ). Mountain areas are rich in many archaeological sites that are part of our cultural heritage and diversity (e.g., Giannakopoulou & Kaliampakos, 2020Giannakopoulou, S. & Kaliampakos, D., 2020. Social transformations of cultural heritage: from benefaction to sponsoring: Evidence from mountain regions in Greece. Journal of Mountains Science, 17: 1475-1490. doi.org/10.1007/s11629-019-5928-3 ) (Figure 1). In Europe, one of the good examples is the agricultural terraces that are good evidence of human adaptation to harsh environments for food production (Brown et al., 2021Brown, A.G., Fallu, D., Walsh, K., Cucchiaro, C., Tarolli, P., Zhao, P., Pears, B.R., Van Oost, K., Lang, A., Albert, R.A., Alsos, I.G. & Waddigton, C., 2021. Ending the Cinderella status of terraces and lynchets in Europe: The geomorphology of agricultural terraces and implications for ecosystem services and climate adaptation. Geomorphology, 379: 107579. doi.org/10.1016/j.geomorph.2020.107579 ). Important archaeological sites classified as UNESCO heritage sites are located in mountain areas, such as Historic Sanctuary of Machu Picchu (Peru), Phnom Kulen (Cambodia), Prehistoric Rock Art Sites in the Côa Valley and Siega Verde (Portugal), Sacri Monti of Piedmont and Lombardy (Italy) and Archaeological Site of Delphi (Greece) (https://whc.unesco.org/en/list/). Finally, mountain areas are excellent laboratories to develop cutting edge research and to understand important phenomena such as climate change (e.g., glacier dynamics, Bach et al., 2018Bach, E., Radic, V. & Schoof, C., 2018. How sensitive are mountain glaciers to climate change? Insights from a block model. Journal of Glaciology, 64: 247-258. doi.org/10.1017/jog.2018.15 ; vegetation processes, García-Ruiz et al., 2015García-Ruiz, J.M., López-Moreno, J.I., Lasanta, T., Vicente-Serrano, S.M., González-Sampériz, P., Valero-Garcés, B.L., Sanjuán, Y., Beguería, S., Nadal-Romero, E., Lana-Renault, N. & Gómez-Villar, A., 2015. Los efectos geoecológicos del cambio global en el Pirineo central español: una revisión a distintas escalas espaciales y temporales. Geo-ecological effects of global change in the central Spanish Pyrenees: a review at different spatial and temporal scales. Pirineos, 170: e012. doi.org/10.3989/Pirineos.2015.170005 ), pre-historical human development (e.g., Dreslerová et al., 2020Dreslerová, D., Kozáková, R., Metlička, M., Brychová, B., Bobek, P., Čišecký, C., Demján, P., Lisá, L., Pokorná, A., Michálek, J., Strouhalová, B. & Trubač, J., 2020. Seeking the meaning of a unique mountain site through a multidisciplinary approach. The Late La Tène site at Sklářské Valley, Šumava Mountains, Czech Republic. Quaternary International, 542: 88-108. doi.org/10.1016/j.quaint.2020.03.013 ), the interaction between past climate change and human expansion, i.e., agriculture and mining (e.g., lake sediments/pollen, Rey et al., 2017Rey, F., Gobet, E., van Leeuwen, J.F.N., Gilli, A., van Raden, U.J., Hafner, A/. Wey, O., Rhiner, J., Schmocker, D., Zünd, J. & Tinner, W., 2017. Vegetational and agricultural dynamics at Burgäschisee (Swiss Plateau) recorded for 18,700 years by multi-proxy evidence from partly varved sediments. Vegetation History and Archaeobotany, 26: 571-586. doi.org/10.1007/s00334-017-0635-x ), land degradation (e.g., overgrazing, Umuhoza et al., 2021Umuhoza, J., Jiapaer, G., Yin, H., Mind’je, R., Gasirabo, A., Nzabarinda, V. & Dufatanye Umwali, E., 2021. The analysis of grassland carrying capacity and its impact factors in typical mountain areas in Central Asia-A case of Kyrgyzstan and Tajikistan. Ecological Indicators, 131: 108129. doi.org/10.1016/j.ecolind.2021.108129 ) or land abandonment (e.g., rural exodus/vegetation encroachment, Nadal-Romero et al., 2021Nadal-Romero, E., Rubio, P., Kremyda, V., Absalah, T., Cammeraat, E., Jansen, B. & Lasanta, T., 2021. Effects of agricultural land abandonment on soil organic carbon stocks and composition of soil organic matter in the Central Spanish Pyrenees. Catena, 205: 105441. doi.org/10.1016/j.catena.2021.105441 ) (Figure 1).
5. Drivers of change impacts on ecosystem services
⌅Drivers of change are defined as any action from humans (e.g., land-use change, political decisions) or natural (e.g., earthquakes, volcanic eruptions) origin that can affect directly or indirectly the ecosystems dynamic. These disturbances can positively or negatively impact the ecosystems (Mikša et al., 2020Mikša, K., Kalinauskas, M., Inacio, M., Gomes, E. & Pereira, P., 2020. Ecosystem services and legal protection of private property. Problem or solution? Geography and Sustainability, 1: 173-180. doi.org/10.1016/j.geosus.2020.08.003 ; Pereira, 2020Pereira, P., 2020. Ecosystem services in a changing environment. Science of the Total Environment, 702: 135008. doi.org/10.1016/j.scitotenv.2019.135008 ). Mountains are subjected to several drivers of change that can dramatically alter ecosystems and their capacity to supply ES in quality and quantity, such as habitat change, climate change, overexploitation, pollution and invasive species. These drivers of change can act alone or combined, increasing the capacity to change the ecosystems (Pereira, 2020Pereira, P., 2020. Ecosystem services in a changing environment. Science of the Total Environment, 702: 135008. doi.org/10.1016/j.scitotenv.2019.135008 ).
5.1. Habitat change
⌅Habitat change has been dramatic in some mountain environments and occurs in different forms (e.g., urban and agricultural expansion/land abandonment) (Figure 1). The drivers of change imposed by recreation and tourism are changing mountains dramatically (e.g., land-use change, habitat fragmentation, conflicts with wildlife, noise, air and soil pollution, greenhouse gas emissions, land degradation, i.e., erosion). This has been observed in the Alps (e.g.; Orsi et al., 2020Orsi, F., Scuttari, A. & Marcher, A., 2020. How much traffic is too much? Finding the right vehicle quota for a scenic mountain road in the Italian Alps. Case Studies on Transport Policy. 8: 1270-1284. doi.org/10.1016/j.cstp.2020.08.007 ), Pyrenees (e.g., Badoque et al., 2017Badoque, J.M., Ballesteros-Cánovas, J.A., Rubiales, J.M., Perucha, M.A., Nadal-Romero, E. & Stoffel, M., 2017. Quantifying Soil Erosion from Hiking Trail in a Protected Natural Area in the Spanish Pyrenees. Land Degradation and Development, 28: 2255-2267. doi.org/10.1002/ldr.2755 ), Himalayas (e.g., Yang et al., 2021Yang, L., Luo, W., Zhao, P., Zhang, Y., Kang, S., Giesy, J.P. & Zhang, F., 2021. Microplastics in the Koshi River, a remote alpine river crossing the Himalayas from China to Nepal. Environmental Pollution, 290: 118121. doi.org/10.1016/j.envpol.2021.118121 ), Tatra mountains (Fidelus-Orzechowska et al., 2021Fidelus-Orzechowska, J., Gorczyca, E., Bukowski, M. & Krzemień, K., 2021. Degradation of a protected mountain area by tourist traffic: case study of the Tatra National Park, Poland. Journal of Mountain Science, 18: 2503-2519. doi.org/10.1007/s11629-020-6611-4 ), to mention some. For instance, Skiing resorts development has a detrimental impact on soil properties, vegetation distribution, biodiversity (Hudek et al., 2020Hudek, C., Barni, E., Stanchi, S., D’Amico, M., Pintaldi, E. & Freppaz, M., 2020. Mid and long-term ecological impacts of ski run construction on alpine ecosystems. Scientific Reports, 10: 11654. doi.org/10.1038/s41598-020-67341-7 ), geomorphological features (Wrońska-Wałach et al., 2019Wrońska-Wałach, D., Cebulski, J., Fidelus-Orzechowska, J., Żelazny, M. & Piątek, D., 2019. Impact of ski run construction on atypical channel head development. Science of the Total Environment, 692: 791-805. doi.org/10.1016/j.scitotenv.2019.07.083 ) and wildlife (Stott et al., 2019Stott T., 2019. Skiing, Snowboarding, and Snowshoeing. In: Outdoor Recreation. Palgrave Macmillan, Cham., pp. 267-297. doi.org/10.1007/978-3-319-97758-4_11 ). Another popular activity that is changing mountain habitats is mountaineering (e.g., climbing, trekking, hiking, biking) (Apollo, 2021Apollo M., 2021. Environmental Impacts of Mountaineering: General Introduction. In: Environmental Impacts of Mountaineering. Springer Briefs in Environmental Science. Springer, Cham. doi.org/10.1007/978-3-030-72667-6_1 ). Several works highlighted that the climbers, hikers and bikers are altering land relief and soil (e.g., soil erosion), vegetation and grazers behaviour, animal feeding grounds, and increasing trail degradation, litter and excrement pollution (e.g., Apollo & Andreychouk, 2020Apollo, M. & Andreychouk, V., 2020. Mountaineering and the natural environment in developing countries: an insight to a comprehensive approach. International Journal of Environmental Studies, 77: 942-953. doi.org/10.1080/00207233.2019.1704047 ; Evju et al., 2021Evju, M., Hagen, D., Jokerud, M., Olsen, S.L., Kjendlie Selvaag, S. & Inge Vistad, O., 2021. Effects of mountain biking versus hiking on trails under different environmental conditions. Journal of Environmental Management, 278: 111554. https://doi.org/10.1016/j.jenvman.2020.111554 ). Although recreation and tourism activities are beneficial for local economies, retain people in rural areas and favour the development of outdoor activities important for human wellbeing (Hanna et al., 2019Hanna, P., Wijesinghe, S., Paliatsos, I., Walker, C., Adams, M. & Kimbu, A., 2019. Active engagement with nature: outdoor adventure tourism, sustainability and wellbeing. Journal of Sustainable Tourism, 27: 1355-1373. doi.org/10.1080/09669582.2019.1621883 ), there are important tradeoffs associated with the loss of regulating ES, such as global and local climate regulation (Delgado et al., 2007Delgado, R., Sánchez-Marañón, M., Martín-García, M., Serrano-Bernardo, F. & Rosúa, J.L., 2007. Impact of ski pistes on soil properties: a case study from a mountainous area in the Mediterranean region. Soil Use Management, 23: 269-277. doi.org/10.1111/j.1475-2743.2007.00093.x ), air quality regulation, water purification, flow and nutrient regulation (e.g., Ristic et al., 2012Ristic, R., Kasanin-Grubin, M., Radic, B., Nikic, Z., Vasiljevic, N., 2012. Land Degradation at the Stara Planina Ski Resort. Environmental Management, 49: 580-592. doi.org/10.1007/s00267-012-9812-y ), natural hazards regulation (Arnaud-Fassetta et al., 2005Arnaud-Fassetta, G., Cossart, E. & Fort, M., 2005. Hydro-geomorphic hazards and impact of man-made structures during the catastrophic flood of June 2000 in the Upper Guil catchment (Queyras, Southern French Alps). Geomorphology, 66: 41-67. doi.org/10.1016/j.geomorph.2004.03.014 ) and pollination (e.g., grassland flora diversity, Bacchiocchi et al., 2019Bacchiocchi, S.C., Zerbe, S., Caviers, L.A. & Wellstein, C., 2019. Impact of ski piste management on mountain grassland ecosystems in the Southern Alps. Science of the Total Environment, 665: 959-967. doi.org/10.1016/j.scitotenv.2019.02.086 ). The expansion of ski resorts has a strong impact on the conversion of grasslands and agricultural areas to the urban fabric, decreasing the capacity of these ecosystems to supply biomass for energy and food (García-Ruiz & Lasanta, 1993García-Ruiz. J.M.& Lasanta, T., 1993. Land-Use Conflicts as a Result of Land-Use Change in the Central Spanish Pyrenees: A Review. Mountain Research Development, 13: 295-304. doi.org/10.2307/3673658 ; Theobald et al., 1996Theobald, D.M., Gosnell, H. & Riebsame, W.E., 1996. Land Use and Landscape Change in the Colorado Mountains II: A Case Study of the East River Valley. Mountain Research Development, 16: 407-418.), respectively. Also, negative impacts were identified on the local cultural activities (Pickering et al., 2003Pickering, C.M., Harrington, J. & Worboys, G., 2003. Environmental Impacts of Tourism on the Australian Alps Protected Areas. Mountain Research and Development, 23: 247-254. ).
In several mountains of the world, such as in the Peruvian Andes (Tovar et al., 2013Tovar, C., Seijmonsbergen, A.C. & Duivenvoorden, J.F., 2013. Monitoring land use and land cover change in mountain regions: An example in the Jalca grasslands of the Peruvian Andes. Landscape and Urban Planning, 112: 40-49. doi.org/10.1016/j.landurbplan.2012.12.003 ), Ethiopian highlands (Kidane et al., 2012Kidane, Y., Stahlmann, R &, Beierkuhnlein, C., 2012. Vegetation dynamics, and land use and land cover change in the Bale Mountains, Ethiopia. Environmental Monitoring and Assessment, 184: 7473-7486. doi.org/10.1007/s10661-011-2514-8 ) or Thailand (Choenkwan et al., 2014Choenkwan, S., Fox, J.M. & Rambo, A.T., 2014. Agriculture in the Mountains of Northeastern Thailand: Current Situation and Prospects for Development. Mountain Research and Development, 34: 95-106. doi.org/10.1659/MRD-JOURNAL-D-13-00121.1 ), the pressure for food security and increasing market demand, are increasing the agriculture area expansion. The agriculture intensification in mountain areas can be profitable in the short term regarding food production and can support recreation and tourism activities. Nevertheless, agriculture intensification may have negative impacts on the ecosystems capacity to regulate the climate and the air quality (e.g., Cai et al., 2019Cai, P., Hamdi, R., Luo, G., He, H., Zhang, M., Termonia, P. & De Maeyer, P., 2019. Agriculture intensification increases summer precipitation in Tianshan Mountains, China. Atmospheric Research, 227: 140-146. doi.org/10.1016/j.atmosres.2019.05.005 ), water purification, flow, erosion and nutrients (e.g., Rukundo et al., 2018Rukundo, E., Liu, S., Dong, Y., Rutebuka, E., Frimpong Asamoah, E.F., Xu, J. & Wu, X., 2018. Spatio-temporal dynamics of critical ecosystem services in response to agricultural expansion in Rwanda, East Africa. Ecological Indicators, 89: 697-705. doi.org/10.1016/j.ecolind.2018.02.032 ), natural hazards (e.g., Erena & Worku, 2018Erena, S.H. & Worku, H., 2018. Flood risk analysis: causes and landscape-based mitigation strategies in Dire Dawa city, Ethiopia. Geoenvironmental Disasters, 5: 16. doi.org/10.1186/s40677-018-0110-8 ) and pollination (e.g., Ritten et al., 2018Ritten, C.J., Peck, D., Ehmke, M. & Patalee, M.A.B., 2018. Firm Efficiency and Returns-to-Scale in the Honey Bee Pollination Services Industry. Journal of Economic Entomology, 111: 1014-1022. doi.org/10.1093/jee/toy075 ). Although there has been observed a trend in the increase of mountain areas agriculture, others have been affected by land abandonment, a complex socio-ecological phenomenon observed in several mountain areas of Europe (Lasanta et al., 2017Lasanta, T., Errea, M.P. & Nadal-Romero, E., 2017. Traditional Agrarian Landscape in the Mediterranean Mountains. A Regional and Local Factor Analysis in the Central Spanish Pyrenees. Land Degradation and Development, 28(5): 1626-1640. doi.org/10.1002/ldr.2695 ) and Asia (Han & Song 2019Han, Z. & Song, W., 2019. Spatiotemporal variations in cropland abandonment in the Guizhou-Guangxi karst mountain area, China. Journal of Cleaner Production, 238: 117888. doi.org/10.1016/j.jclepro.2019.117888 ). Land abandonment imposes an important disturbance in mountain ecosystems, which can have positive or negative impacts. Associated with land abandonment is the rewilding process that favours several regulating ES such as global and local climate regulation, through the increase of carbon sequestration (e.g., Bell et al., 2020Bell, S.M., Barriocanal, C., Terrer, C. & Rosell-Melé, A., 2020. Management opportunities for soil carbon sequestration following agricultural land abandonment. Environmental Science & Policy, 108: 104-111. doi.org/10.1016/j.envsci.2020.03.018 ) and water purification, erosion and nutrient regulation (e.g., Lizaga et al., 2018Lizaga, I., Quijano, L., Gaspar, L. & Navas, A., 2018. Estimating soil redistribution patterns with 137Cs measurements in a Mediterranean mountain catchment affected by land abandonment. Land Degradation and Development, 29: 105-117. doi.org/10.1002/ldr.2843 ) and biomass for energy and timber (e.g., Pitman & Peace, 2021Pitman, R.M. & Peace, A., 2021. Mulch versus brash: a case study of in situ harvesting residue treatment and its effects on C and nutrients in soil and plant uptake during natural rewilding. Trees, Forests and People, 6: 100121. doi.org/10.1016/j.tfp.2021.100121 ). As a consequence of vegetation encroachment, there is an increase in plant water consumption, evapotranspiration, consumption and storage. This reduces water flow and the quantity of water that reaches rivers (Khorchani et al., 2021Khorchani, M., Nadal-Romero, E., Lasanta, T. & Tague, C., 2021. Natural revegetation and afforestation in abandoned cropland areas: Hydrological trends and changes in Mediterranean mountains. Hydrological Processes, 35: e14191. doi.org/10.1002/hyp.14191 ) and aquifers (Ouyang et al., 2021Ouyang, Y., Jin, W., Leininger, T.D., Feng, G. & Yang, J., 2021. Impacts of afforestation on groundwater resource: a case study for Upper Yazoo River watershed, Mississippi, USA. Hydrological Sciences Journal, 66: 464-473. doi.org/10.1080/02626667.2021.1876235 ). Afforestation reduces the probability of flash floods and landslides (e.g., Dittrich et al., 2018Dittrich, R., Ball, T., Wreford, A., Moran, D. & Spray, C.J., 2018. A cost-benefit analysis of afforestation as a climate change adaptation measure to reduce flood risk. Journal of Flood Risk Management, 12: e12482. doi: 10.1111/jfr3.12482 ; Hu et al., 2021Hu, S., Jiao, J., Kou, M., Wang, N., García-Fayos, P. & Liu, S., 2021. Quantifying the effects of Robinia pseudoacacia afforestation on plant community structure from a functional perspective: New prospects for management practices on the hilly and gullied Loess Plateau, China. Science of the Total Environment, 773: 144878. doi.org/10.1016/j.scitotenv.2020.144878 ). On the other hand, land abandonment and vegetation encroachment increase the fuel available and risk wildfire occurrence (Palaiologou et al., 2017Palaiologou, P., Ager, A.A., Nielsen-Pincus, M., Evers, C.R. & Kalabokidis, K., 2017. Using transboundary wildfire exposure assessments to improve fire management programs: a case study in Greece. International Journal of Wildland Fire, 27: 501-513. doi.org/10.1071/WF1711 ). Regarding the impacts of land abandonment/afforestation on natural hazards regulation, there is an important tradeoff between flood/landslides mitigation and wildfire risk. To mitigate this, it is essential to establish fuel management policies (e.g., prescribed fires) to reduce fire risk without compromising flood regulation (Pereira et al., 2021Pereira, P., Bogunovic, I., Zhao, W. & Barceló, D., 2021. Short-term effect of wildfires and prescribed fires on ecosystem services. Current Opinion in Environmental Science & Health, 22: 100266 doi.org/10.1016/j.coesh.2021.100266 ). Land abandonment decreases the capacity of mountain areas to provide food. In this process, traditions, cultural activities and landscapes are lost (e.g., Hanaček & Rodríguez-Labajos, 2018Hanaček, K. & Rodríguez-Labajos, B., 2018. Impacts of land-use and management changes on cultural agroecosystem services and environmental conflicts-A global review. Global Environmental Change, 50: 41-59. doi.org/10.1016/j.gloenvcha.2018.02.016 ). For instance, one of the most evident impacts is the agricultural terraces destruction due to lack of maintenance (Stavi et al., 2018Stavi, I., Rozenberg, T., Al-Ashhab, A., Argaman, E. & Groner, E., 2018. Failure and Collapse of Ancient Agricultural Stone Terraces: On-Site Effects on Soil and Vegetation. Water, 10: 1400. https://doi.org/10.3390/w10101400 ). The destruction of these structures can trigger soil, water losses, floods and landslides (e.g., Moreno-de-las-Heras et al., 2019Moreno-de-las-Heras, M., Lindenberger, F., Latron, J., Lana-Renault, N., Llorens, P., Arnáez, J., Romero-Díaz, A. & Gallart, F., 2019. Hydro-geomorphological consequences of the abandonment of agricultural terraces in the Mediterranean region: Key controlling factors and landscape stability patterns. Geomorphology, 333: 73-91. doi.org/10.1016/j.geomorph.2019.02.014 ).
Dam construction for hydropower production dramatically impacts freshwater habitats fragmentation, river ecological function and thermal regimes, nutrient and sediment flux and biodiversity loss (Vuong Pham et al., 2019Vuong Pham, H., Torresan, S., Critto, A. & Marcomini, A., 2019. Alteration of freshwater ecosystem services under global change - A review focusing on the Po River basin (Italy) and the Red River basin (Vietnam). Science of the Total Environment, 652: 1347-1365. doi.org/10.1016/j.scitotenv.2018.10.303 ; Barbarossa et al., 2020Barbarossa, V., Schmitt, R.J.P., Huijbregts, M.A.J., Zarfl, C., King, H. & Schipper, A.M., 2020. Impacts of current and future large dams on the geographic range connectivity of freshwater fish worldwide. Proceedings of the National Academy of Sciences of the United States of America, 117, 3648-3655. doi.org/10.1073/pnas.1912776117 ). Although these infrastructures increase the amount of energy produced from renewable resources, they have profound impacts on fish spawning migratory routes and affect the communities that depend on this resource for food supply (Dugan et al., 2010Dugan, P.J., Barlow, C., Baran, E., Cada, G.F., Chen, D., Cowx, I.G., Ferguson, J.W., Jutagate, T., Mallen-Cooper, M.M., Marmulla, G., Nestler, J., Petrere, J., Welcomme, R.L. & Winemiller, K.O., 2010. Fish Migration, Dams, and Loss of Ecosystem Services in the Mekong Basin. Ambio, 39: 344-348. doi.org/10.1007/s13280-010-0036-1 ). Also, wind farms imposed a high disruption in the environment, and several works highlight that they disturb the natural habitats strongly and negatively affect the different trophic levels (e.g., Thaker et al., 2018Thaker, M., Zambre, A. & Bhosale, H., 2018. Wind farms have cascading impacts on ecosystems across trophic levels. Nature Ecology & Evolution, 2: 1854-1858. doi.org/10.1038/s41559-018-0707-z ; Fernández-Bellon et al., 2019Fernández-Bellon, D., Wilson, M.W., Irwin, S. & O’Halloran, J., 2019. Effects of development of wind energy and associated changes in land use on bird densities in upland areas. Conservation Biology, 33: 413-422. doi.org/10.1111/cobi.13239 ). These infrastructures have negative impacts on recreation and tourism (Ólafsdóttir & Sæþórsdóttir, 2019Ólafsdóttir, R. & Sæþórsdóttir, A.D., 2019. Wind farms in the Icelandic highlands: Attitudes of local residents and tourism service providers. Land Use Policy, 88: 104173. doi.org/10.1016/j.landusepol.2019.104173 ), landscape aesthetics, noise (Kalinauskas et al., 2021Kalinauskas, M., Miksa, K., Inacio, M., Gomes, E. & Pereira, P., 2021. Mapping and assessment of landscape aesthetic quality in Lithuania. Journal of Environmental Management, 286: 112239. doi.org/10.1016/j.jenvman.2021.112239 ) and cultural heritage (Nazir et al., 2020Nazir, M.S., Bilal, M., Sohail, H.H., Liu, B., Chen, W. & Iqbal, H.F.N., 2020. Impacts of renewable energy atlas: Reaping the benefits of renewables and biodiversity threats. International Journal of Hydrogen Energy, 45: 22113-22124. doi.org/10.1016/j.ijhydene.2020.05.195 ). Finally, as the previous renewable energy resources, solar energy may impose a negative impact on habitats loss and reduce the habitats for pollinators (e.g., McCoshum & Geber, 2020McCoshum. S.M. & Geber, M.A., 2020. Land Conversion for Solar Facilities and Urban Sprawl in Southwest Deserts Causes Different Amounts of Habitat Loss for Ashmeadiella Bees. Journal of the Kansas Entomological Society, 92: 468-478. doi.org/10.2317/0022-8567-92.2.468 ) and landscape aesthetics (e.g., visual quality) (Dhar et al., 2020Dhar, A., Naeth, M.A., Jennings, P.D. & Gamal el-Din, M., 2020. Perspectives on environmental impacts and a land reclamation strategy for solar and wind energy systems. Science of the Total Environment, 718: 134602. doi.org/10.1016/j.scitotenv.2019.134602 ).
5.2. Climate change
⌅Climate change (e.g., glacier melting, extreme events, and drought periods) negatively affects mountain ecosystems and their capacity to supply services (Figure 1). Although all ES are predicted to be affected, the most relevant impacts are expected in global and local climate regulation, natural hazards regulation, crops, wild food and fish provisioning, freshwater provisioning, renewable energy, recreation and tourism, landscape aesthetics and cultural heritage and cultural diversity (Palomo, 2017Palomo, I., 2017. Climate Change Impacts on Ecosystem Services in High Mountain Areas: A Literature Review. Mountain Research and Development, 37: 179-187. doi.org/10.1659/MRD-JOURNAL-D-16-00110.1 ; Hua et al., 2021Hua, T., Zhao, W., Cherubini, F., Hu, X. & Pereira, P., 2021. Sensitivity and future exposure of ecosystem services to climate change on the Tibetan Plateau of China. Landscape Ecology, 36: 3451-3471. doi.org/10.1007/s10980-021-01320-9 ).
Mountain ecosystems are highly vulnerable to small changes in the climate (e.g., Iglesias et al., 2018Iglesias, V., Whitlock, C., Krause, T.R. & Baker, R.G., 2018. Past vegetation dynamics in the Yellowstone region highlight the vulnerability of mountain systems to climate change. Journal of Biogeography, 45(8): 1768-1780. doi.org/10.1111/jbi.13364 ) and, therefore, to ecosystem change (e.g., tree-line upward) (Cazzolla Gatti et al., 2019Cazzolla Gatti, R., Callaghan, T., Velichevskaya, A., Dudko, A., Fabbio, L., Battipaglia, G., Liang, J., 2019. Accelerating upward treeline shift in the Altai Mountains under last-century climate change. Scientific Reports, 9: 7678. doi.org/10.1038/s41598-019-44188-1 ). This will likely affect carbon sequestration (global and local climate regulation) (Hua et al., 2021Hua, T., Zhao, W., Cherubini, F., Hu, X. & Pereira, P., 2021. Sensitivity and future exposure of ecosystem services to climate change on the Tibetan Plateau of China. Landscape Ecology, 36: 3451-3471. doi.org/10.1007/s10980-021-01320-9 ). As a consequence of glacier and permafrost melting and increase in extreme events, natural hazards (e.g., flash floods, landslides, rockfall) are expected to be more frequent and severe (e.g., Terzi et al., 2019Terzi, S., Torresan, S., Schneiderbauer, S., Critto, A., Zebisch, M. & Marcomini, A., 2019. Multi-risk assessment in mountain regions: A review of modelling approaches for climate change adaptation. Journal of Environmental Management, 232: 759-771. doi.org/10.1016/j.jenvman.2018.11.100 ; Viani et al., 2020Viani, C., Chiarle, M., Paranunzio, R., Merlone, A., Musacchio, C., Coppa, G. & Nigrelli, G., 2020. An integrated approach to investigate climate-driven rockfall occurrence in high alpine slopes: the Bessanese glacial basin, Western Italian Alps. Journal of Mountain Science, 17: 2591-2610. doi.org/10.1007/s11629-020-6216-y ). The increase of wildfires frequency can amplify the high vulnerability to natural hazards, severity and recurrence in a climate change context (e.g., Taboada et al., 2017Taboada, A., Tarrega, R., Marcos, E., Vallbuena, L., Suárez-Seoane, S. & Calvo, L., 2017. Fire recurrence and emergency post-fire management influence seedling recruitment and growth by altering plant interactions in fire-prone ecosystems. Forest Ecology and Management, 402: 63-75. doi.org/10.1016/j.foreco.2017.07.029 ; Cassell et al., 2019Cassell, B.A., Scheller, R.M., Lucash, M.S., Hurteau, M.D. & Loudermilk, E.L., 2019. Widespread severe wildfires under climate change lead to increased forest homogeneity in dry mixed-conifer forests. Ecosphere, 10: e02934. doi.org/10.1002/ecs2.2934 ). High temperatures and the prevalence of long and frequent drought periods are expected to increase the vulnerability to wildfires. Severe and recurrent wildfires are the ones that impose more ecosystems damage and affect drastically the ecosystems capacity to recover. Therefore, the expected increase of severe wildfires may trigger other natural hazards such as flash floods (e.g., Nolan et al., 2018Nolan, R.H., Sinclair, J., Eldridge, D.J. & Ramp, D., 2018. Biophysical risks to carbon sequestration and storage in Australian drylands. Journal of Environmental Management, 208: 102-111. doi.org/10.1016/j.jenvman.2017.12.002 ; Coscarelli et al., 2021Coscarelli, R., Aguilar, E., Petrucci, O., Vicente-Serrano, S.M. & Zimbo, F., 2021. The Potential Role of Climate Indices to Explain Floods, Mass-Movement Events and Wildfires in Southern Italy. Climate, 9: 156. doi.org/10.3390/cli9110156 ).
The alteration of temperature and precipitation patterns due to climate change will affect the water availability (e.g., glacier melting, reduced snow cover, drought periods) for food production in mountain communities (e.g., Poudel & Duex, 2017Poudel, D.D. & Duex, T.W., 2017. Vanishing Springs in Nepalese Mountains: Assessment of Water Sources, Farmers’ Perceptions, and Climate Change Adaptation. Mountain Research and Development, 37: 35-46. doi.org/10.1659/MRD-JOURNAL-D-16-00039.1 ), but also in lowland areas that depend on water from glacier and snow melting to irrigate their fields (Huss et al., 2017Huss, M., Bookhagen, B., Huggel, C., Jacobsen, D., Bradley, R.S., Clague, J.J., Vuille, M., Buytaert, W., Cayan, D.R., Greenwood, G., Mark, B.G., Milner, A.M., Weingartner, R. & Winder, M., 2017. Toward mountains without permanent snow and ice. Earth’s Future, 5: 418-435. doi.org/10.1002/2016EF000514 ). Also, climate change impact on ecosystems shift will affect the distribution of wild foods such as berries (Prevéy et al., 2020Prevéy, J.S., Parker, L.E., Harrington, C.A., Lamb, C.T. & Proctor, M.F., 2020. Climate change shifts in habitat suitability and phenology of huckleberry (Vaccinium membranaceum). Agricultural and Forest Meteorology, 280: 107803. doi.org/10.1016/j.agrformet.2019.107803 ) and mushrooms (Yang et al., 2012Yang, X., Luedeling, E., Chen, G., Hyde, K.D., Yang, Y., Zhou, D., Xu, J. & Yang, Y., 2012. Climate change effects fruiting of the prize matsutake mushroom in China. Fungal Diversity, 56: 189-198. doi.org/10.1007/s13225-012-0163-z ). This impact on mushrooms productivity in some mountain ranges (e.g., Prades Mountains, Catalonia-Spain) will be negative (Karavani et al., 2018Karavani, A., De Cáceres, M., Martínez de Aragón, J., Bonet, J.A. & de-Miguel, S., 2018. Effect of climatic and soil moisture conditions on mushroom productivity and related ecosystem services in Mediterranean pine stands facing climate change. Agricultural and Forest Meteorology, 248: 432-440. doi.org/10.1016/j.agrformet.2017.10.024 ). Climate change will also affect adversely mountain grasslands (e.g., afforestation) (Schirpke et al., 2017Schirpke, U., Kohler, M., Leitinger, G., Fontana, V., Tasser, E. & Tappeiner, U., 2017. Future impacts of changing land-use and climate on ecosystem services of mountain grassland and their resilience. Ecosystem Services, 26: 79-94. doi.org/10.1016/j.ecoser.2017.06.008 ). The sensitivity to climate change increases with the increasing altitude (Li et al., 2019aLi, L., Zhang, Y., Wu, J., Li, S., Zhang, B., Zu, J., Zhang, H., Ding, M., & Paudel, B., 2019a. Increasing sensitivity of alpine grasslands to climate variability along an elevational gradient on the Qinghai-Tibet Plateau. Science of the Total Environment, 678: 21-29. doi.org/10.1016/j.scitotenv.2019.04.399 ), which will have implications on their capacity to supply food for cattle.
Climate change is also expected to negatively impact hydropower energy, mainly due to the snow and ice cover decrease and the reduced glacier volumes that will negatively affect runoff and energy production. These harmful impacts are mainly identified in dry areas, such as central Asia or the tropical Andes, where runoff volume depends on glacier melting (Huss et al., 2017Huss, M., Bookhagen, B., Huggel, C., Jacobsen, D., Bradley, R.S., Clague, J.J., Vuille, M., Buytaert, W., Cayan, D.R., Greenwood, G., Mark, B.G., Milner, A.M., Weingartner, R. & Winder, M., 2017. Toward mountains without permanent snow and ice. Earth’s Future, 5: 418-435. doi.org/10.1002/2016EF000514 ). Decreases in hydropower production were also observed in other regions such as California (Forrest et al., 2018Forrest, K., Tarroja, B., Chiang, F., AghaKouchak, A. & Samuelsen, S., 2018. Assessing climate change impacts on California hydropower generation and ancillary services provision. Climatic Change, 151: 395-412. doi.org/10.1007/s10584-018-2329-5 ), Brazil (Oliveira et al., 2017Oliveira, V.A., Mello, C.R., Viola, M.R. & Srinivasan, R., 2017. Assessment of climate change impacts on streamflow and hydropower potential in the headwater region of the Grande river basin, Southeastern Brazil. International Journal of Climatology, 37: 5005-5023. doi.org/10.1002/joc.5138 ) or Portugal (Teotónio et al., 2017Teotónio, C., Fortes, P., Roebeling, P., Rodriguez, M., & Robaina-Alves, M., 2017. Assessing the impacts of climate change on hydropower generation and the power sector in Portugal: A partial equilibrium approach. Renewable and Sustainable Energy Reviews, 74: 788-799. doi.org/10.1016/j.rser.2017.03.002 ). On the other hand, in regions where precipitation is expected to be high (e.g., Three Gorges Reservoir - China), hydropower energy will increase (Qin et al., 2020Qin, P., Xu, H., Liu, M., Du, L., Xiao, C., Liu, L. & Tarroja, B., 2020. Climate change impacts on Three Gorges Reservoir impoundment and hydropower generation. Journal of Hydrology, 580: 123922. doi.org/10.1016/j.jhydrol.2019.123922 ).
Climate change has a negative and positive impact on mountain recreation and tourism. Winter sports will be negatively affected by the decreasing number of days with snow and ice cover (e.g., Fang et al., 2021Fang, Y., Scott, D. & Steiger, R., 2021. The impact of climate change on ski resorts in China. International Journal of Biometeorology, 65: 677-689. doi.org/10.1007/s00484-019-01822-x ). Several solutions have been established to tackle this problem, such as show snowmaking. However, this solution increases energy and water demand (Rixen et al., 2011Rixen, C., Teich, M., Lardelli, C., Gallati, D., Pohl, M., Pütz, M. & Bebi, P., 2011. Winter Tourism and Climate Change in the Alps: An Assessment of Resource Consumption, Snow Reliability, and Future Snowmaking Potential. Mountain Research and Development, 31: 229-236. https://doi.org/10.1659/MRD-JOURNAL-D-10-00112.1 ) and has negative impacts on mountain ecosystems (Wrońska-Wałach et al., 2019Wrońska-Wałach, D., Cebulski, J., Fidelus-Orzechowska, J., Żelazny, M. & Piątek, D., 2019. Impact of ski run construction on atypical channel head development. Science of the Total Environment, 692: 791-805. doi.org/10.1016/j.scitotenv.2019.07.083 ). Glacier tourism is also being affected since most mountain glaciers are disappearing, bringing substantial losses to this industry (Wang & Zhou, 2019Wang, S.J. & Zhou, L.Y., 2019. Integrated impacts of climate change on glacier tourism. Advances in Climate Change Research, 10: 71-79. doi.org/10.1016/j.accre.2019.06.006 ). Other phenomena related to climate change, such as the wildfire risk increase, discourage tourists from travelling to these areas (Pereira et al., 2021Pereira, P., Bogunovic, I., Zhao, W. & Barceló, D., 2021. Short-term effect of wildfires and prescribed fires on ecosystem services. Current Opinion in Environmental Science & Health, 22: 100266 doi.org/10.1016/j.coesh.2021.100266 ). However, mountain tourism can benefit during heatwave periods, where people can look for refuges in high altitude areas. Finally, climate change and the impacts on seasonality can affect the time when tourists visit mountain areas (Palomo, 2017Palomo, I., 2017. Climate Change Impacts on Ecosystem Services in High Mountain Areas: A Literature Review. Mountain Research and Development, 37: 179-187. doi.org/10.1659/MRD-JOURNAL-D-16-00110.1 ).
The disappearance of mountain glaciers decreases landscape aesthetics since tourists highly appreciate this landscape, as observed in previous works (e.g., Welling et al., 2020Welling, J., Árnason, Þ. & Ólafsdóttir, R., 2020. Implications of Climate Change on Nature-Based Tourism Demand: A Segmentation Analysis of Glacier Site Visitors in Southeast Iceland. Sustainability, 112: 5338. doi.org/10.3390/su12135338 ; Salim et al., 2021Salim, E., Ravanel, L., Deline, P. & Gauchon, C., 2021. A review of melting ice adaptation strategies in the glacier tourism context. Scandinavian Journal of Hospitality and Tourism, 21: 229-246. doi.org/10.1080/15022250.2021.1879670 ). The increasing wildfire frequency will decrease temporarily landscape quality and the attractiveness of these areas to be visited (Pereira et al., 2021Pereira, P., Bogunovic, I., Zhao, W. & Barceló, D., 2021. Short-term effect of wildfires and prescribed fires on ecosystem services. Current Opinion in Environmental Science & Health, 22: 100266 doi.org/10.1016/j.coesh.2021.100266 ). Around the world, several mountain landscapes are sacred for different communities located in the Meili Snow Mountains of Yunnan (China), Nepalese Himalaya, Peruvian Andes, Alaska or Canada. The loss of these glaciers will have a detrimental impact on the communities living in these areas (Allison, 2015Allison, E.A., 2015. The spiritual significance of glaciers in an age of climate change. WIREs Climate Change, 6: 493-508. doi.org/10.1002/wcc.354 ; Thornton et al., 2019Thornton, T.F., Rudolph, M., Geiger, W. & Geiger, A., 2019. A Song Remembered in Place: Tlingit Composer Mary Sheakley (Loo) and Huna Tlingits in Glacier Bay National Park, Alaska. Journal of Ethnobiology, 39: 392-408. doi.org/10.2993/0278-0771-39.3.392 ).
5.3. Overexploitation
⌅Mountain environments are subjected to high overexploitation, threatening biodiversity and ES supply (Figure 1). For instance, hunting and poaching practices cause biodiversity loss in some mountainous areas (e.g., Adhikari et al., 2021Adhikari, L., Khan, B., Joshi, S., Ruijun, L., Ali, G., Muhammad Shah, G., Ismail, M., Bano, M., Ali, R., Khan, G. & Pasakhala, B., 2021. Community-based trophy hunting programs secure biodiversity and livelihoods: Learnings from Asia’s high mountain communities and landscapes. Environmental Challenges, 4, 100175. doi.org/10.1016/j.envc.2021.100175 ). The mineral resources demand increases the landslides, debris flow, collapse, and ground deformation and subsidence, with severe implications for the populations living in lowland areas (Shao, 2019Shao, L., 2019. Geological disaster prevention and control and resource protection in mineral resource exploitation region. International Journal of Low-Carbon Technologies, 14: 142-149. https://doi.org/10.1093/ijlct/ctz003 ). Mineral exploitation imposes a high degradation in the areas where they are established by removing soil and vegetation, drastically hampering these ecosystems’ capacity to supply regulating, cultural and other provisioning services (e.g., food, freshwater). Overall, these activities impose a high ES value loss (Dawen et al., 2018Dawen, Q., Changzhen, Y., Lina, X. & Kun, F., 2018. The impact of mining changes on surrounding lands and ecosystem service value in the Southern Slope of Qilian Mountains. Ecological Complexity, 36: 138-148. doi.org/10.1016/j.ecocom.2018.08.002 ).
Overgrazing is another threat to regulating (e.g., global and local climate regulation, water purification, flow, erosion and nutrient regulation, pollination) and provisioning (e.g., food for livestock) ES (Figure 1). This has been identified in several mountain areas of Ethiopia (Mekonen, 2020Mekonen, S., 2020. Coexistence between human and wildlife: the nature, causes and mitigations of human wildlife conflict around Bale Mountains National Park, Southeast Ethiopia. BMC Ecology, 20: 51. doi.org/10.1186/s12898-020-00319-1 ), China (Hao et al., 2018Hao, L., Pan, C., Zhang, X., Zhou, D., Liu, P., Liu, Y. & Sun, G., 2018. Quantifying the effects of overgrazing on mountainous watershed vegetation dynamics under a changing climate. Science of the Total Environment, 639: 1408-1420. doi.org/10.1016/j.scitotenv.2018.05.224 ), Greece (Fetzel et al., 2018Fetzel, T., Petridis, P., Noll, D., Singh, S.J. & Fischer-Kowalski, M., 2018. Reaching a socio-ecological tipping point: Overgrazing on the Greek island of Samothraki and the role of European agricultural policies. Land Use Policy, 76: 21-28. doi.org/10.1016/j.landusepol.2018.04.042 ) and Central Asia (Nowak et al., 2020Nowak, A., Świerszcz, S., Nowak, S., Hisorev, H., Klichowska, E., Wróbel, A., Nobis, A. & Nobis, M., 2020. Red List of vascular plants of Tajikistan - the core area of the Mountains of Central Asia global biodiversity hotspot. Scientific Reports, 10: 6235. https://doi.org/10.1038/s41598-020-63333-9 ), to mention some. For instance, overgrazing reduces the grassland capacity to store carbon (e.g., Zhou et al., 2020Zhou H., Wang D., Guo M., Yao B. & Shang Z., 2020. Promoting Artificial Grasslands to Improve Carbon Sequestration and Livelihood of Herders. In: Shang Z., Degen A., Rafiq M., Squires V. (eds.) Carbon Management for Promoting Local Livelihood in the Hindu Kush Himalayan (HKH) Region. pp. 211-228. Springer, Cham. https://doi.org/10.1007/978-3-030-20591-1_12 ), grassland biodiversity (e.g., Nowak et al., 2020Nowak, A., Świerszcz, S., Nowak, S., Hisorev, H., Klichowska, E., Wróbel, A., Nobis, A. & Nobis, M., 2020. Red List of vascular plants of Tajikistan - the core area of the Mountains of Central Asia global biodiversity hotspot. Scientific Reports, 10: 6235. https://doi.org/10.1038/s41598-020-63333-9 ), increases soil and nutrient loss (e.g., Zheng et al., 2017Zheng, Q., Liu, Y., Fang, Y., Ma, R., Lal, R., An, S. & Huang, Y., 2017. Impact of vegetation restoration on plants and soil C:N:P stoichiometry on the Yunwu Mountain Reserve of China. Ecological Engineering, 109: 92-100. doi.org/10.1016/j.ecoleng.2017.10.003 ; Li et al., 2019bLi, Y., Li, J., Steven Are, K., Huang, Z., Yu, H. & Zhang, Q., 2019b. Livestock grazing significantly accelerates soil erosion more than climate change in Qinghai-Tibet Plateau: Evidenced from 137Cs and 210Pbex measurements. Agriculture, Ecosystems & Environment, 285: 106643. doi.org/10.1016/j.agee.2019.106643 ) and reduce pollinators abundance (Naeem et al., 2019Naeem, M., Liu, M., Huang, J., Ding, G., Potapov, G., Jung, C. & An, J., 2019. Vulnerability of East Asian bumblebee species to future climate and land cover changes. Agriculture, Ecosystems & Environment, 277: 11-20. doi.org/10.1016/j.agee.2019.03.002 ). Mountain Forest overexploitation (e.g., timber production) is also a reality in several environments (e.g., Payne et al., 2020Payne, D., Snethlage, M., Geschke, J., Spehn, E.M. & Fischer, M., 2020. Nature and People in the Andes, East African Mountains, European Alps, and Hindu Kush Himalaya: Current Research and Future Directions. Mountain Research and Development, 40: A1-A14. doi.org/10.1659/MRD-JOURNAL-D-19-00075.1 ), imposing a degradation in the capacity of these ecosystems to regulate global and local climate, air quality (Rawat et al., 2021Rawat, D., Sati, S.P., Khanduri, V.P., Riyal, M., Mishra, G. 2021. Carbon Sequestration Potential of Different Land Use Sectors of Western Himalaya. In: Pant D., Kumar Nadda A., Pant K.K., Agarwal A.K. (eds): Advances in Carbon Capture and Utilization. Energy, Environment, and Sustainability. pp. 273-294. Springer, Singapore. https://doi.org/10.1007/978-981-16-0638-0_12 ), water purification, flow, erosion and nutrient regulation (e.g., Negash et al., 2021Negash, D.A., Moisa, M.B., Merga, B.B., Sedeta, F., & Gemeda, D.O., 2021. Soil erosion risk assessment for prioritization of sub-watershed: the case of Chogo Watershed, Horo Guduru Wollega, Ethiopia. Environmental Earth Sciences 80: 589. doi.org/10.1007/s12665-021-09901-2 ), natural hazards and pollination. It also negatively impacts non-timber products (e.g., Soe & Yeo-Chang, 2019Soe, K.T. & Yeo-Chang, Y., 2019. Livelihood Dependency on Non-Timber Forest Products: Implications for REDD+. Forests, 10: 427. doi.org/10.3390/f10050427 ), landscape aesthetics, and cultural heritage (e.g., Zeb et al., 2019Zeb, A., Hamann, A., Armstrong, G.W. & Acuna-Castellanos, D., 2019. Identifying local actors of deforestation and forest degradation in the Kalasha valleys of Pakistan. Forest Policy and Economics, 104: 56-67. doi.org/10.1016/j.forpol.2019.04.005 ) since several of these areas are considered sacred.
Agriculture intensification in mountain environments also implies a natural resources overexploitation (e.g., water), and it is responsible for soil quality degradation (e.g., von Westarp et al., 2004von Westarp, S., Schreir, H., Brown, S. & Shah, P.B., 2004. Agricultural intensification and the impacts on soil fertility in the Middle Mountains of Nepal. Canadian Journal of Soil Science, 84: 323-332. doi.org/10.4141/S03-053 ), changes in pedogenesis process (Tang et al., 2019Tang, J., Han, Z., Zhong, S. & Wei, C., 2019. Changes in the profile characteristics of cultivated soils obtained from reconstructed farming plots undergoing agricultural intensification in a hilly mountainous region in southwest China with regard to anthropogenic pedogenesis. Catena, 180: 132-145. doi.org/10.1016/j.catena.2019.04.020 ), erosion (West et al., 2015West, A.J., Arnold, M., AumaÎtre, G., Bourlès, D.L., Keddadouche, K., Bickle, M. & Ojha, T., 2015. High natural erosion rates are the backdrop for present-day soil erosion in the agricultural Middle Hills of Nepal. Earth Surface Dynamics, 3: 363-387. doi.org/10.5194/esurf-3-363-2015 ) and deforestation (Munwar & Udelhoven, 2020Munwar, S. & Udelhoven, T., 2020. Land change syndromes identification in temperate forests of Hindukush Himalaya Karakorum (HHK) mountain ranges. International Journal of Remote Sensing, 41: 7735-7756. doi.org/10.1080/01431161.2020.1763509 ). Although agriculture intensification and resources overexploitation may have some short-term positive impact on food production, it has crucial tradeoffs related to global and local climate, air quality and regulation (Ali et al., 2017Ali, A., Strezov, V., Davies, P. & Wright, I., 2017. Environmental impact of coal mining and coal seam gas production on surface water quality in the Sydney basin, Australia. Environmental Monitoring and Assessment, 189: 408. doi.org/10.1007/s10661-017-6110-4 ), water purification, flow, erosion and nutrient regulation (Locatelli et al., 2017Locatelli, B., Lavorel, S., Sloan, S., Tappeiner, U. & Geneletti, D., 2017. Characteristic trajectories of ecosystem services in mountains. Frontiers in Ecology and the Environment, 15: 150-159. doi.org/10.1002/fee.1470 ), pollination (Christmann et al., 2021Christmann, S., Bencharki, Y., Anougmar, S., Rasmont, P., Smaili, M.C., Tsivelikas, A. & Aw-Hassan, A., 2021. Farming with Alternative Pollinators benefits pollinators, natural enemies, and yields, and offers transformative change to agriculture. Scientific Reports, 11: 18206. doi.org/10.1038/s41598-021-97695-5 ), freshwater supply (Rolando et al., 2017Rolando, J.L., Turin, C., Ramírez, D.A., Mares, V., Monerris, J., Quiroz, R., 2017. Key ecosystem services and ecological intensification of agriculture in the tropical high-Andean Puna as affected by land-use and climate changes. Agriculture, Ecosystems & Environment, 236: 221-233. doi.org/10.1016/j.agee.2016.12.010 ), recreation and tourism (Locatelli et al., 2017Locatelli, B., Lavorel, S., Sloan, S., Tappeiner, U. & Geneletti, D., 2017. Characteristic trajectories of ecosystem services in mountains. Frontiers in Ecology and the Environment, 15: 150-159. doi.org/10.1002/fee.1470 ), landscape aesthetics and cultural heritage (Albizua et al., 2019Albizua, A., Pascual, U. & Corbera, E., 2019. Large-scale Irrigation Impacts Socio-cultural Values: An Example from Rural Navarre, Spain. Ecological Economics, 159: 354-361. doi.org/10.1016/j.ecolecon.2018.12.017 ). Mass tourism expansion increases overexploitation (e.g., Ganie et al., 2019Ganie, A.J., Tali, B.A., Khuroo, A.A., Reshi, Z.A. & Nawchoo, I.A., 2019. Impact assessment of anthropogenic threats to high-valued medicinal plants of Kashmir Himalaya, India. Journal for Nature Conservation, 50: 125715. doi.org/10.1016/j.jnc.2019.125715 ; Mateusz, 2021Mateusz, R., 2021. A method to analyze variability and seasonality the visitors in mountain national park in period 2017-2020 (Stołowe Mts. National Park; Poland). Journal of Outdoor Recreation and Tourism, 35: 100407. doi.org/10.1016/j.jort.2021.100407 ). For instance, unregulated tourism harms the overexploitation of medicinal plants (Ganie et al., 2019Ganie, A.J., Tali, B.A., Khuroo, A.A., Reshi, Z.A. & Nawchoo, I.A., 2019. Impact assessment of anthropogenic threats to high-valued medicinal plants of Kashmir Himalaya, India. Journal for Nature Conservation, 50: 125715. doi.org/10.1016/j.jnc.2019.125715 ), fuelwood (Laiolo et al., 2004Laiolo, P., 2004. Diversity and structure of the bird community overwintering in the Himalayan subalpine zone: is conservation compatible with tourism? Biological Conservation, 115: 251-262. doi.org/10.1016/S0006-3207(03)00145-9 ) and water (Singh et al., 2020Singh, S., Tanvir Hassan, S.M., Hassan, M. & Bharti, N., 2020. Urbanisation and water insecurity in the Hindu Kush Himalaya: Insights from Bangladesh, India, Nepal and Pakistan. Water Policy, 22: 9-32. doi.org/10.2166/wp.2019.215 ) in the Himalaya. In the Mediterranean mountains, mass tourism is causing an increase in groundwater exploitation (Pulido-Bosch et al., 2020Pulido-Bosch, A., Vallejos, A., Sola, F., & Molina, L., 2020. Groundwater Sustainability Strategies in the Sierra de Gador-Campo de Dalias System, Southeast Spain. Water, 12: 3262. doi.org/10.3390/w12113262 ).
5.4. Pollution
⌅Mining activities are responsible for high levels of soil and water resources pollution (in the site and off-site) in several mountains of the world, located in Asia (e.g., Wang et al., 2019Wang, Y., Dong, R., Zhou, Y. & Luo, X., 2019. Characteristics of groundwater discharge to river and related heavy metal transportation in a mountain mining area of Dabaoshan, Southern China. Science of the Total Environment, 679: 346-358. https://doi.org/10.1016/j.scitotenv.2019.04.273 ), North America (e.g., Lemly, 2019Lemly, A.D., 2019. Environmental hazard assessment of Benga Mining’s proposed Grassy Mountain Coal Project. Environmental Science and Policy, 96: 105-113. https://doi.org/10.1016/j.envsci.2019.03.010 ), Europe (e.g., Kupková et al., 2018Kupková, L., Potůčková, M., Lhotáková, Z. & Albrechtová, J., 2018. Forest cover and disturbance changes, and their driving forces: A case study in the Ore Mountains, Czechia, heavily affected by anthropogenic acidic pollution in the second half of the 20th century. Environmental Research Letters, 13: 095008. doi.org/10.1088/1748-9326/aadd2c ), Africa (e.g., Khelifi et al., 2021Khelifi, F., Caporale, A.G., Hamed, Y. & Adamo, P., 2021. Bioaccessibility of potentially toxic metals in soil, sediments and tailings from a north Africa phosphate-mining area: Insight into human health risk assessment. Journal of Environmental Management, 279: 111634. doi.org/10.1016/j.jenvman.2020.111634 ) and Australia (e.g., Ali et al., 2017Ali, A., Strezov, V., Davies, P. & Wright, I., 2017. Environmental impact of coal mining and coal seam gas production on surface water quality in the Sydney basin, Australia. Environmental Monitoring and Assessment, 189: 408. doi.org/10.1007/s10661-017-6110-4 ) (Figure 1). The overexploitation of mineral resources is one of the most important causes of land degradation (Gabarrón et al., 2019Gabarrón, M., Zornoza, R., Acosta, J.A., Faz, A. & Martínez-Martínez, S., 2019. Mining environments. In: Pereira, P. Soil Degradation, Restoration and Management in a Global Change Context. pp. 175-205. Elsevier. Amsterdam). Mining harms all the biotic ES 1) regulating (global and local climate; air quality; natural hazards; pollination) and 2) provisioning (crops, livestock, wild food and fish, biomass for energy and timber and freshwater) since mining exploitation involves vegetation and soil removal (e.g., Lee et al., 2017Lee, S.H., Ji, W., Yang, H.J., Kang, S.Y. & Kang, D.M., 2017. Reclamation of mine-degraded agricultural soils from metal mining: lessons from 4 years of monitoring activity in Korea. Environmental Earth Sciences, 76: 720. doi.org/10.1007/s12665-017-7076-9 ; Rajan, 2019Rajan, R., 2019. Assessing the impact of mining on deforestation in India. Resources Policy, 60: 23-35. doi.org/10.1016/j.resourpol.2018.11.022 ) and increase waterbodies pollution (e.g., Santana et al., 2020Santana, C.S., Montalván Olivares, D., Silva, V.H.C., Luzardo, F.H.M., Velasco, F.G. & Jesus, R.M., 2020. Assessment of water resources pollution associated with mining activity in a semi-arid region. Journal of Environmental Management, 273: 111148. doi.org/10.1016/j.jenvman.2020.111148 ). Also, the mining industry affected negatively cultural heritage in several countries (e.g., Ghana and Western Australia) (Apoh et al., 2017Apoh, A., Wissing, K., Treasure, W. & Fardin, J., 2017. Law, land and what lies beneath: exploring mining impacts on customary law and cultural heritage protection in Ghana and Western Australia. African Identities, 15: 367-386. https://doi.org/10.1080/14725843.2017.1319752 ). Paradox to the above mentioned, there is a growing interest in preserving old mines as part of cultural landscape and history in some regions (e.g., Pardo Abad et al., 2017Pardo Abad, C.J., 2017. The post-industrial landscapes of Riotinto and Almadén, Spain: scenic value, heritage and sustainable tourism. Journal of Heritage Tourism, 12: 331-346. doi.org/10.1080/1743873X.2016.1187149 ).
Agriculture intensification increases soil and water pollution (e.g., agrochemicals, microplastics) (Ennaji et al., 2020Ennaji, W., Barakat, A., El Baghdadi, M. & Rais, J., 2020. Heavy metal contamination in agricultural soil and ecological risk assessment in the northeast area of Tadla plain, Morocco. Journal of Sedimentary Environments, 5: 307-320. doi.org/10.1007/s43217-020-00020-9 ; Feng et al., 2021Feng. S., Lu, H. & Liu, Y., 2021. The occurrence of microplastics in farmland and grassland soils in the Qinghai-Tibet plateau: Different land use and mulching time in facility agriculture. Environmental Pollution, 279: 116939. doi.org/10.1016/j.envpol.2021.116939 ), and this has been observed in several mountain areas (e.g., Wu et al., 2020Wu, S., Yin, P., Wang, M., Zhou, L. & Geng, R., 2020. A new watershed eco-zoning scheme for evaluate agricultural nonpoint source pollution at national scale. Journal of Cleaner Production, 273: 123033. doi.org/10.1016/j.jclepro.2020.123033 ; Li et al., 2021Li, L., Gou, M., Wang, N., Ma, W., Xiao, W., Liu, C. & La, L., 2021. Landscape configuration mediates hydrology and nonpoint source pollution under climate change and agricultural expansion. Ecological Indicators, 129: 107959. doi.org/10.1016/j.ecolind.2021.107959 ). Although some benefits are obtained from crop production, agriculture intensification and the impacts on soil are decreasing their capacity to regulate nutrients, and there are high losses through overland flow (e.g., Strohmenger et al., 2020Strohmenger, L., Fovet, O., Akkal-Corfini, N., Dupas, R., Durand, P., Faucheux, M., Gruau, M., Hamon, Y., Jaffrezic, A., Minaudo, C., Petitjean, P. & Gascuel-Odoux, C., 2020. Multitemporal Relationships Between the Hydroclimate and Exports of Carbon, Nitrogen, and Phosphorus in a Small Agricultural Watershed. Water Resources Research, 56: e2019WR026323. doi.org/10.1029/2019WR026323 ). It is also well known that agrochemicals harm plants flowering and pollinators (e.g., Dupont et al., 2018Dupont, Y., Strandberg, B. & Damgaard, C., 2018. Effects of herbicide and nitrogen fertilizer on non-target plant reproduction and indirect effects on pollination in Tanacetum vulgare (Asteraceae). Agriculture, Ecosystems & Environment, 262: 76-82. doi.org/10.1016/j.agee.2018.04.014 ), reduce freshwater quality (e.g., Loecke et al., 2017Loecke, T.D., Burgin, A.J., Riveros-Iregui, D.A., Ward, A.S., Thomas, S.A., Davis, C.A. & Clair, M.A.S., 2017. Weather whiplash in agricultural regions drives deterioration of water quality. Biogeochemistry, 133: 7-15. doi.org/10.1007/s10533-017-0315-z ) and decrease the waterbodies capacity to supply fish due to diffuse pollution (e.g., Godinho et al., 2019Godinho, F.N., Segurado, P., Franco, A., Pinheiro, P., Padua, J., Rivaes, R. & Ramos, P., 2019. Factors related to fish kill events in Mediterranean reservoirs. Water Research, 158: 280-290. doi.org/10.1016/j.watres.2019.04.027 ).
The development of tourist infrastructures in mountain areas increases the pollution and greenhouse gases emission (Jamnongchob et al., 2017Jamnongchob, A., Duangphakdee, O. & Hanpattanakit, P., 2017. CO2 emission of tourist transportation in Suan Phueng Mountain, Thailand. Energy Procedia, 136: 438-443. doi.org/10.1016/j.egypro.2017.10.300 ) due road development, traffic increase (Sundriyal et al., 2018Sundriyal, A., Shridhar, V., Madhwal, S., Pandey, K. & Sharma, V., 2018. Impacts of tourism development on the physical environment of Mussoorie, a hill station in the lower Himalayan range of India. Journal of Mountain Science, 15: 2276-2291. doi.org/10.1007/s11629-017-4786-0 ), infrastructure construction, waste production (Semernya et al., 2017Semernya, L., Ramola, A., Alfthan, B. & Giacovelli, C., 2017. Waste management outlook for mountain regions: Sources and solutions. Waste Management and Research, 35: 935-939. doi.org/10.1177/0734242X17709910 ) and litter in wildland environments (Hu et al., 2018Hu, H., Zhang, J., Chu, G., Yang, J. & Yu, P., 2018. Factors influencing tourists’ litter management behavior in mountainous tourism areas in China. Waste management, 79: 273-286. https://doi.org/10.1016/j.wasman.2018.07.047 ). Although for the region, this can represent an increase in recreation and tourism activities. It will have important tradeoffs on other ES such as air quality regulation, pollination and freshwater supply (Sundriyal et al., 2018Sundriyal, A., Shridhar, V., Madhwal, S., Pandey, K. & Sharma, V., 2018. Impacts of tourism development on the physical environment of Mussoorie, a hill station in the lower Himalayan range of India. Journal of Mountain Science, 15: 2276-2291. doi.org/10.1007/s11629-017-4786-0 ; Kamel, 2020Kamel, M., 2020. Impact of hiking trails on the diversity of flower-visiting insects in Wadi Telah, St. Katherine protectorate, Egypt. The Journal of Basic and Applied Zoology, 81: 52. doi.org/10.1186/s41936-020-00188-6 ).
5.5. Invasive species
⌅Invasive species in mountain environments are a consequence of multiple human impacts such as land-use change (e.g., plantations), nitrogen deposition and tourism development (e.g., infrastructure development) (Figure 1). Other aspects such as the herbivores abundance, pests and diseases, wildfires or landslides have implications on plants distribution. Climate change has direct (e.g., productivity, competitive balance, phenology) and indirect (e.g., changes in hydrological regime) impacts on plant distribution. Although the invasive species spread in mountain areas is not so easy as in other ecosystems due to climate conditions, when alien species pass this filter, it is complicated to manage and reverse their spread due to the complex topography. Invasive species in mountain environments is a global phenomenon and are mostly of agricultural origin (McDougall et al., 2010McDougall, K.L., Alexander, J.M., Haider, S., Pauchard, A., Walsh, N.G. & Kueffer, C., 2010. Alien flora of mountains: global comparisons for the development of local preventive measures against plant invasions. Diversity and Distributions, 17: 103-111. doi.org/10.1111/j.1472-4642.2010.00713.x , 2011; Kueffer et al., 2013Kueffer, C., McDougall, K., Alexander, J., Daehler, C., Edwards, P., Haider, S., Milbau, S., Parks, C., Pauchard, A., Reshi, Z.A., Rew, Z.A., Schroder, M. & Seipel, S., 2013. Plant Invasions into Mountain Protected Areas: Assessment, Prevention and Control at Multiple Spatial Scales. In: Foxcroft L., Pyšek P., Richardson D., Genovesi P. (eds) Plant Invasions in Protected Areas. Invading Nature - Springer Series in Invasion Ecology, vol 7. pp. 89-113. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-7750-7_6 ).
For instance, the proliferation of Eucalyptus spp. (a native specie from Australia) for timber production in several mountains of the world has dramatic impacts on the environment. This specie is planted in all the continents i.e., Africa (Piiroinen et al., 2018Piiroinen, R., Ewald Fassnacht, F., Heiskanen, J., Maeda, E., Mack, B. & Pellikka, P., 2018. Invasive tree species detection in the Eastern Arc Mountains biodiversity hotspot using one class classification. Remote Sensing of Environment, 218: 119-131. doi.org/10.1016/j.rse.2018.09.018 ), America (Durán et al., 2017Durán, R., Isik, F., Zapata-Valenzuela, J., Balocchi, C. & Valenzuela, S., 2017. Genomic predictions of breeding values in a cloned Eucalyptus globulus population in Chile. Tree Genetics & Genomes, 13: 74. doi.org/10.1007/s11295-017-1158-4 ), Europe (Oliveira & Tome, 2017Oliveira, T.S. & Tome, M., 2017. Improving biomass estimation for Eucalyptus globulus Labill at stand level in Portugal. Biomass and Bioenergy, 96: 103-111. doi.org/10.1016/j.biombioe.2016.11.010 ) and Asia (Chen et al., 2021Chen, W., Zou, Y., Dang, Y. & Sakai, T., 2021. Spatial distribution and dynamic change monitoring of Eucalyptus plantations in China during 1994-2013. Trees doi.org/10.1007/s00468-021-02215-7 ). Eucalyptus ssp. plantations are well known to have a high-water consumption than the native forests (White et al., 2021White, D.A., Silberstein, R.P., Balocchi-Contreras, F., Quiroga, J.J., Meason, D.F., Palma, J.H.N. & Ramírez de Arellano, P., 2021. Growth, water use, and water use efficiency of Eucalyptus globulus and Pinus radiata plantations compared with natural stands of Roble-Hualo forest in the coastal mountains of central Chile. Forest Ecology and Management, 501: 119676. doi.org/10.1016/j.foreco.2021.119676 ), reduce biodiversity (Deus et al., 2018Deus, E., Silva, J.S., Castro-Díez, P., Lomba, A. Ortiz, M.L. & Vicente, J., 2018. Current and future conflicts between eucalypt plantations and high biodiversity areas in the Iberian Peninsula. Journal for Nature Conservation, 45: 107-117. doi.org/10.1016/j.jnc.2018.06.003 ), increase soil degradation (Banfield et al., 2018Banfield, C.C., Braun, A.C., Barra, R., Castillo, A. & Vogt, J., 2018. Erosion proxies in an exotic tree plantation question the appropriate land use in Central Chile. Catena, 161: 77-84. doi.org/10.1016/j.catena.2017.10.017 ) and the vulnerability to wildfire risk (Nunes, 2012Nunes, A.N., 2012. Regional variability and driving forces behind forest fires in Portugal an overview of the last three decades (1980-2009). Applied Geography, 34: 576-586. doi.org/10.1016/j.apgeog.2012.03.002 ). Rubber, palm oil plantations are other invasive species that cause high land degradation in mountain areas (e.g., Leite et al., 2018Leite, A., Caceres, A., Melo, M., Mills, M.S.L. & Monteiro, A.T., 2018. Reducing emissions from Deforestation and forest Degradation in Angola: Insights from the scarp forest conservation ‘hotspot’. Land Degradation and Development, 29: 4291-4300. https://doi.org/10.1002/ldr.3178 ; Vijith et al., 2018Vijith, H., Hurmain, A. & Dodge-Wan, D., 2018. Impacts of land use changes and land cover alteration on soil erosion rates and vulnerability of tropical mountain ranges in Borneo. Remote Sensing Applications: Society and Environment, 12: 57-69. doi.org/10.1016/j.rsase.2018.09.003 ).
Tourism development is an important cause of plant invasion. For example, hiking trails and roadsides are considered major paths of alien plants spread in mountain areas (Liedtke et al., 2020Liedtke, R., Barros, A., Essl, F., Lembrechts, J.J., Wedegärtner, R.E.M., Pauchard, P. & Dullinger, S., 2020. Hiking trails as conduits for the spread of non-native species in mountain areas. Biological Invasions, 22: 1121-1134. doi.org/10.1007/s10530-019-02165-9 ). Also, the introduction of species of fish (Tiberti et al., 2019Tiberti, R., Bogliani, G., Brighenti, S., Iacobuzio, R., Liautaud, Rolla, M., von Hardenberg, A. & Bassano, B., 2019. Recovery of high mountain Alpine lakes after the eradication of introduced brook trout Salvelinus fontinalis using non-chemical methods. Biological Invasions, 21: 875-894. doi.org/10.1007/s10530-018-1867-0 ) and herbivores (Martín-Esquivel et al., 2020Martín-Esquivel, J.L., Marrero-Gómez, M., Cubas, J., González-Mancebo, J.M., Olano, J.M. & del Arco, M., 2020. Climate warming and introduced herbivores disrupt alpine plant community of an oceanic island (Tenerife, Canary Islands). Plant Ecology, 221: 1117, 1131. doi.org/10.1007/s11258-020-01066-5 ) in high lands dramatically impact native fauna. There are several examples where the introduction of non-native herbivores leads to a very high environmental degradation (e.g., sheep in Iceland, Barrio et al., 2018Barrio, I.C., Hik, D.S., Thórsson, J., Svavarsdóttir, K., Marteinsdóttir, B. & Svala Jónsdóttir. I., 2018. The sheep in wolf’s clothing? Recognizing threats for land degradation in Iceland using state-and-transition models. Land Degradation and Development, 29: 1714-1725. doi.org/10.1002/ldr.2978 ).
Finally, climate change is expected to increase invasive species spread in mountain areas. However, this is a more serious problem in low land areas. Since mountain areas have a harsh climate, the alien species spread is difficult. However, climate change may favour the environmental conditions required for non-native species that affect high altitudes (Petitpierre et al., 2016Petitpierre, B., McDougall, K., Seipel, T., Broennimann, O., Guisan, A. & Kueffer, C., 2016. Will climate change increase the risk of plant invasions into mountains? Ecological Applications, 26(2): 530-544. doi.org/10.1890/14-1871 ). In addition, as mentioned previously, with climate change, it is expected that wildfires will be more severe and frequent, increasing the risk for plant invasion, as observed in previous works (e.g., Reilly et al., 2020Reilly, M.J., McCord, M.G., Brandt, S.M., Linowksi, K.P., Butz. R.J. & Jules, E.S., 2020. Repeated, high-severity wildfire catalyzes invasion of non-native plant species in forests of the Klamath Mountains, northern California, USA. Biological Invasions, 22: 1821-1820. doi.org/10.1007/s10530-020-02227-3 ).
Several studies have been developed about the impact of invasive species on ES (e.g., Vilà & Hulme, 2017Vilà, M. & Hulme, P.E., 2017. Non-native Species, Ecosystem Services, and Human Well-Being. In: Vilà M., Hulme P. (eds): Impact of Biological Invasions on Ecosystem Services. Invading Nature - Springer Series in Invasion Ecology, vol. 12. pp. 1-14. Springer, Cham. https://doi.org/10.1007/978-3-319-45121-3_1 ; Rai & Singh, 2020Rai, P.K. & Singh, J.S., 2020. Invasive alien plant species: Their impact on environment, ecosystem services and human health. Ecological Indicators, 111: 106020. doi.org/10.1016/j.ecolind.2019.106020 ). There are several tradeoffs involved in the impacts of invasive species in mountain environments. Forest plantations can have some benefits in the production of biomass for energy and timber. However, they have a low capacity to regulate global and local climate than native forests (Yu et al., 2019Yu, Z., Liu, S., Wang, J., Wei, X., Schler, J., Sun, P., Harper, R. & Zegre, N., 2019. Natural forests exhibit higher carbon sequestration and lower water consumption than planted forests in China. Global Change Biology, 25: 68-77. doi.org/10.1111/gcb.14484 ). Therefore, the establishment of non-native species plantations cannot be considered an advantage. Plantations affect the capacity of the ecosystem dramatically to regulate water flow, erosion and nutrients - mainly in young plantations - (e.g., Liu et al., 2017Liu, W., Luo, Q., Lu, H., Wu, J. & Duan, W., 2017. The effect of litter layer on controlling surface runoff and erosion in rubber plantations on tropical mountain slopes, SW China. Catena, 149: 167-175. doi.org/10.1016/j.catena.2016.09.013 ), pollination (Potts et al., 2010Potts, S.G., Biesmeijer, J.C., Kremen, C., Neumann, P., Schweiger, O. & Kunin, W.E., 2010. Global pollinator declines: trends, impacts and drivers. Trends in Ecology and Evolution, 25: 345-353. doi.org/10.1016/j.tree.2010.01.007 ), freshwater supply (León-Muñoz et al., 2017León-Muñoz, J., Echeverría, C., Fuentes, R. & Aburto, F., 2017. How is the land use-cover changing in drinking water catchments in the coastal range of south-central Chile (35º-38.5º S)? Bosque, 38: 203-209. Doi 10.4067/S0717-92002017000100020 ) and recreation and tourism (Benra et al., 2019Benra, F., Nahuelhual, L., Gaglio, M., Gissi, E., Aguayo, M., Jullian, C. & Bonn, C., 2019. Ecosystem services tradeoffs arising from non-native tree plantation expansion in southern Chile. Landscape and Urban Planning, 190: 103589. doi.org/10.1016/j.landurbplan.2019.103589 ). Climate change impact on invasive species is expected to affect native pollinators negatively (e.g., Schweiger et al., 2010Schweiger, O., Biesmeijer, J.C., Bommarco, R., Hickler, T., Hulme, P.E., Klotz, S., Kühn, I., Moora, M., Nielsen, A., Ohlemüller, R., Petanidou, T., Potts, S.G., Pyšek, P., Stout, J.C., Sykes, M.T., Tscheulin, T., Vilà, M., Walther, G.R., Westphal, C., Winter, M., Zobel, M., & Settele, J., 2010. Multiple stressors on biotic interactions: how climate change and alien species interact to affect pollination. Biological Reviews, 85: 777-795. doi.org/10.1111/j.1469-185X.2010.00125.x ; Silva et al., 2021Silva, C.R.B., Beaman, J.E., Dorey, J.B., Barker, S.J., Congedi, N.C., Elmer, M.C., Galvin, S., Tuiwawa, M., Stevens, M.I., Alton, L.A., Schwarz, M.P. & Kellermann, V., 2021. Climate change and invasive species: a physiological performance comparison of invasive and endemic bees in Fiji. Journal of Experimental Botany, 224: jeb230326. doi.org/10.1242/jeb.230326 ).
6. Conclusion
⌅Mountains ecosystems are key for human existence and provide many biotic and abiotic ES to the local communities and lowland inhabitants. Although these environments can be inhospitable and challenging to colonise, humans have developed strategies oaf adaptation and established flourishing civilisations in mountain areas throughout history. The ES supply by these environments is immense, though their exploitation can produce different tradeoffs. The excessive exploitation of one determined ES (e.g., mining) can trigger a cascade of adverse effects in all the other ES. Therefore, to maintain the continuous ES supply in quantity and quality, it is vital to rationalising all ES’s exploitation to reach the necessary equilibrium in utilising mountain resources. Sustainable approaches are needed in the ES management in mountain environments. This is a challenge for our and future generations.