Climate Change and Its Impact on Brown Bear Distribution in Iran


  • Sahar Roshan Ara Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Iran
  • Sohrab Ashrafi Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Iran
  • Roghayeh Garmaeepour Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Iran
  • Mohammad Zarrintab Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Iran
  • Nariman Askaripour Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Iran
  • Sorour Esfandeh Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Iran



Climate change is one of the threats in the recent century, affecting biodiversity directly and indirectly. Modeling the patterns of species distribution is one of useful tools for predicting the impacts of climate change on endangered species. Brown bear (Ursus arctos) plays an important role as a focal species in mountainous ecosystems. This study was aims to investigate the effects of future climate changes on the distribution of this species using an ensemble modeling method in R-software. For this purpose five algorithms including MAXENT, RF, MARS, GAM, GLM and BRT were used to predict the distribution of the species in the present climatic conditions as well as in the 2050s and 2070s. The results showed that temperature and precipitation were two main factors in the distribution of brown bears in Iran. Investigating the distribution of the brown bear in the future showed that suitability of its habitat will decrease in the western and central parts and increase in the northern parts. So a shift toward higher altitude will be expected for brown bear in the future. Therefore, in this condition it is imperative to upgrade the extent of protected areas for better conservation of brown bear.


Iran; Ursus arctos; Species distribution modeling; R software; Predicting


[1] Houghton, J.T., et al., 2001. IPCC Third Assessment Report: Climate Change 2001 (Cambridge Univ. Press, Cambridge.

[2] Peterson, A.T., Ortega-Huerta, M.A., Bartley, J., Sánchez-Cordero, V., Soberón, J., Buddemeier, R.H., Stockwell, D.R., 2002. Future projections for Mexican faunas under global climate change scenarios. Nature. 416(6881), 626-9.

[3] Araújo, M.B., New, M., 2007. Ensemble forecasting of species distributions. Trends in ecology & evolution. 22(1), 42-47.

[4] Bellard, C., Bertelsmeier, C., Leadley, P., Thuiller, W., Courchamp, F., 2012. Impacts of climate change on the future of biodiversity. Ecology letters. 15(4), 365- 377.

[5] Kafash, A., Kaboli, M., Koehler, G., Yousefi, M.,Asadi, A., 2016. Ensemble distribution modeling of the Mesopotamian spiny-tailed lizard, Saara loricata (Blanford, 1874), in Iran: an insight into the impact of climate change. Turkish Journal of Zoology. 40(2), 262-71.

[6] Chapin Iii, F.S., Zavaleta, E.S., Eviner, V.T., Naylor, R.L., Vitousek, P.M., Reynolds, H.L., et al., 2000. Consequences of changing biodiversity. Nature. 405(6783), 234-42.

[7] Pereira, H.M., Leadley, P.W., Proenca, V., Alkemade, R., Scharlemann, J.P.W., Fernandez-Manjarres, J.F., et al., 2010. Scenarios for global biodiversity in the 21st century. Science. 330, 1496-1501.

[8] Kafash, A., Ashrafi, S., Ohler, A., Schmidt, B.R., 2019. Environmental predictors for the distribution of the Caspian green lizard, Lacerta strigata Eichwald, 1831, along elevational gradients of the Elburz Mountains in northern Iran. Turkish Journal of Zoology. 43(1), 106-113.

[9] Thuiller, W., 2007. Biodiversity - climate change and the ecologist. Nature. 448, 550-552.

[10] Elith, J., Phillips, S.J., Hastie, T., Dudik, M., Chee, Y.E., Yates, C.J., 2011. A statistical explanation of MaxEnt for ecologists. Divers Distrib. 17(1), 43-57.

[11] Kafash, A., Kaboli, M., Köhler, G., 2015. Comparison effect of future climatic change on the desert and mountain dwelling reptiles in Iran (Paralaudakia caucasia and Saara loricata). Journal of Animal Environment. 7(3), 103-108.

[12] Phillips, S.J., Anderson, R.P., Schapire, R.E., 2006. Maximum entropy modeling of species geographic distributions. Ecol Model. 190, 231-259.

[13] Yousefi, M., Ahmadi, M., Nourani, E., Rezaei, A., Kafash, A., Khani, A., ... Kaboli, M., 2017. Habitat suitability and impacts of climate change on the distribution of wintering population of Asian Houbara Bustard Chlamydotis macqueenii in Iran. Bird Conservation International. 27(2), 294-304.

[14] Kafash, A., Malakoutikhah, S., Yousefi, M., Ataei, F., Heidari, H., Rastegar-Pouyani, E., 2018. The Gray Toad-headed Agama, Phrynocephalus scutellatus, on the Iranian Plateau: The degree of niche overlap depends on the phylogenetic distance. Zoology in the Middle East. 64(1), 47-54.

[15] Moisen, G.G., Frescino, T.S., 2002. Comparing five modeling techniques for predicting forest characteristics. Ecol Model. 157, 209-225.

[16] Friedman, J., 1991. Multivariate adaptive regression splines. Ann Stat. 1-67.

[17] Breiman, L., 2001. Random forests. Mach Learn. 45, 5-32.

[18] Ridgeway, G., 1999. The state of boosting. Comput Sci Stat. 31, 172-181.

[19] McCullagh, P., Nelder, J.A., 1989. Generalized Linear Models. London, UK: Chapman and Hall.

[20] Guo, Q.H., Kelly, M., Graham, C.H., 2005. Support vector machines for predicting distribution of sudden oak death in California. Ecol Model. 182, 75-90.

[21] Naimi, B., Araújo, M.B., 2016. sdm: a reproducible and extensible R platform for species distribution modelling. Ecography. 39(4), 368-375.

[22] Ridings, C., 2006. Green bear in the desert. International Bear News. 15(2), 12-13.

[23] Boitani, L., Jdeidi, T., Masseti, M., de Smet, K., Cuzin, F., 2008. Ursus arctos. In: IUCN 2008. IUCN Red List of Threatened Species. Version 2009.1, Available at: (Accessed on 30.06.09).

[24] Ashrafzadeh, M.R., Kaboli, M., Naghavi, M.R., 2016. Mitochondrial DNA analysis of Iranian brown bears (Ursus arctos) reveals new phylogeographic lineage. Mammalian Biology-Zeitschrift für Säugetierkunde. 81(1), 1-9.

[25] Sathyakumar, S., Can, O.E., 2007. News and status of South Asian brown bear. International Bear News. 16, 6-9.

[26] Ashrafzadeh, M.R., Khosravi, R., Ahmadi, M., Kaboli, M., 2018. Landscape heterogeneity and ecological niche isolation shape the distribution of spatial genetic variation in Iranian brown bears, Ursus arctos (Carnivora: Ursidae). Mammalian Biology. 93, 64- 75.

[27] Habibzadeh, N., Ashrafzadeh, M.R., 2018. Habitat suitability and connectivity for an endangered brown bear population in the Iranian Caucasus. Wildlife Research. 45(7), 602-610.

[28] Ataei, F., Karami, M., Kaboli, M., 2012. Summer Habitat Suitability Modeling of Brown Bear (Ursus arctos) Southern Alborz Protected Area. Journal of Natural Environment. 65(2), 235-45.

[29] Sántiz, E.C., Lorenzo, C., Carrillo-Reyes, A., Navarrete, D.A., Islebe, G., 2016. Effect of climate change on the distribution of a critically threatened species. Therya. 7(1), 147-59.

[30] Schwalm, D., Epps, C.W., Rodhouse, T.J., Monahan, W.B., Castillo, J.A., Ray, C., Jeffress, M.R., 2016. Habitat availability and gene flow influence diverging local population trajectories under scenarios of climate change: a place-based approach. Glob Change Biol. 22, 1572-1584.

[31] Penteriani, V., Zarzo-Arias, A., Novo-Fernández, A., Bombieri, G., López-Sánchez, C.A., 2019. Re-sponses of an endangered brown bear population to climate change based on predictable food resource and shelter alterations. Global change biology. 25(3), 1133-51.

[32] Hijmans, R.J., Cameron, S.E., Parra, J.L., Jones, P.G., Jarvis, A., 2005. Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology. 25, 1965-1978.

[33] Chapi, K., Singh, V.P., Shirzadi, A., Shahabi, H., Bui, D.T., Pham, B.T., Khosravi, K., 2017. A novel hybrid artificial intelligence approach for flood susceptibility assessment. Environmental Modelling & Software. 95, 229-245.

[34] Sachser, F., Nopp-Mayr, U., Zohmann, M., Schweiger, A.K., Grünschachner-Berger, V., Immitzer, M., 2017. Searching the right tie—Expert-based vs. statistical niche modeling for habitat management at the alpine treeline ecotone. Ecological engineering. 100, 107-119.

[35] Soetaert, K., Petzoldt, T., Setzer, R.W., 2010. Solving differential equations in R: package deSolve. Journal of statistical software. 33, 1-25.

[36] Robinson, C.L., Proudfoot, B., Rooper, C.N., Bertram, D.F., 2021. Comparison of spatial distribution models to predict subtidal burying habitat of the forage fish Ammodytes personatus in the Strait of Georgia, British Columbia, Canada. Aquatic Conservation: Marine and Freshwater Ecosystems. 31(10), 2855-2869.

[37] Porfirio, L.L., Harris, R.M., Lefroy, E.C., Hugh, S., Gould, S.F., Lee, G., ... Mackey, B., 2014. Improving the use of species distribution models in conservation planning and management under climate change. PLoS One. 9(11), e113749.

[38] Freeman, E.A., Moisen, G.G., 2008. A comparison of the performance of threshold criteria for binary classification in terms of predicted prevalence and kappa. Ecological modelling. 217(1-2), 48-58.

[39] Ahmadi, M., Nezami Balouchi, B., Jowkar, H., Hemami, M.R., Fadakar, D., Malakouti‐Khah, S., Ostrowski, S., 2017. Combining landscape suitability and habitat connectivity to conserve the last surviving population of cheetah in Asia. Diversity and Distributions. 23(6), 592-603.

[40] Fourcade, Y., Engler, J.O., Besnard, A.G., Rِdder, D., Secondi, J., 2013. Confronting expert-based and modelled distributions for species with uncertain conservation status: a case study from the corncrake (Crex crex). Biol Conserv. 167, 161-171.

[41] Fielding, A.H., Bell, J.F., 1997. A review of methods for the assessment of prediction errors in conservation presence/absence models. Environ Conserv. 24, 38-49.

[42] Ye, X., Yu, X., Yu, C., Tayibazhaer, A., Xu, F., Skidmore, A.K., Wang, T., 2018. Impacts of future climate and land cover changes on threatened mammals in the semi-arid Chinese Altai Mountains. Science of the total environment. 612, 775-787.

[43] McLellan, M.L., McLellan, B.N., 2015. Effect of season and high ambient temperature on activity levels and patterns of grizzly bears (Ursus arctos). PloS one. 10(2), e0117734.

[44] Farashi, A., Erfani, M., 2018. Modeling of habitat suitability of Asiatic black bear (Ursus thibetanus gedrosianus) in Iran in future. Acta Ecologica Sinica. 38(1), 9-14.

[45] Levinsky, I., Skov, F., Svenning, J.C., Rahbek, C., 2007. Potential impacts of climate change on the distributions and diversity patterns of European mammals. Biodiversity and Conservation. 16(13), 3803- 3816.

[46] Waltari, E., Guralnick, R.P., 2009. Ecological niche modelling of montane mammals in the Great Basin, North America: examining past and present connectivity of species across basins and ranges. Journal of Biogeography. 36(1), 148-161.

[47] Segan, D.B., Murray, K.A., Watson, J.E., 2016. A global assessment of current and future biodiversity vulnerability to habitat loss-climate change interactions. Global Ecology and Conservation. 5, 12-21.

[48] Dar, S.A., Singh, S.K., Wan, H.Y., Kumar, V., Cushman, S.A., Sathyakumar, S., 2021. Projected climate change threatens Himalayan brown bear habitat more than human land use. Animal Conservation.

[49] Pauli, H., Gottfried, M., Dullinger, S., Abdaladze, O., Akhalkatsi, M., Alonso, J.L.B., Coldea, G.J., Dick, R., Kanka, G., Kazakis, J., Kollár, P., Larsson, P., Moiseev, D., Moiseev, U., Molau, J., M. Mesa, L., Nagy, G., Pelino, M., Puşcaş, G., Rossi, A., Stanisci, A.O., Theurillat, M., Tomaselli, P., Unterluggauer, L., Villar, A., Vittoz, P., Grabherr G., 2012. Recent plant diversity changes on Europe’s mountain summits. Science. 336, 353-355.

[50] Humphries, M.M., Thomas, D.W., Speakman, J.R., 2002. Climate-mediated energetic constraints on the distribution of hibernating mammals. Nature. 418, 313-316.

[51] Davidson, A.D., Hamilton, M.J., Boyer, A.G., Brown, J.H., Ceballos, G., 2009. Multiple ecological pathways to extinction in mammals. Proc. Natl. Acad. Sci. USA. 106, 10702-10705.

[52] Koch, P.L., Barnosky, A.D., 2006. Late QuaternaryExtinctions: State of the Debate. Annu. Rev. Ecol. Evol. Syst. 37, 215-250.

[53] Bojarska, K., Selva, N., 2012. Spatial patterns in brown bear Ursus arctos diet: the role of geographical and environmental factors. Mammal Review. 42(2), 120-143.

[54] Tulgat, R., 1995. Gobi Bear (Ursus gobiensis Sokolov et Orlov, 1992) distribution status and habitat past and present. In Proceedings of a conference on Environmental Condition and Biological Resources in Great Gobi Strictly Protected Area, Ulaan Baatar. pp. 110-112.

[55] Qin, A., Jin, K., Batsaikhan, M.E., Nyamjav, J., Li, G., Li, J., ... Xiao, W., 2020. Predicting the current and future suitable habitats of the main dietary plants of the Gobi Bear using MaxEnt modeling. Global Ecology and Conservation. 22, e01032.

[56] GP, M., J, A.K., 2015. Ecological impacts of climate change. Amsterdam, the Netherlands: Elsevier Inc. pp. 397-426.

[57] Shen, G., Pimm, S.L., Feng, C., Ren, G., Liu, Y., Xu, W., ... Xie, Z., 2015. Climate change challenges the current conservation strategy for the giant panda. Biological Conservation. 190, 43-50.

[58] Zang, Z., Shen, G., Ren, G., Wang, C., Feng, C., Xu, W., ... Li, J., 2017. Thermal habitat of giant panda has shrunk by climate warming over the past half century. Biological Conservation. 211, 125-133.

[59] Cianfrani, C., Broennimann, O., Loy, A., Guisan, A., 2018. More than range exposure: Global otter vulnerability to climate change. Biological Conservation. 221, 103-113.

[60] Coogan, S.C., Raubenheimer, D., Stenhouse, G.B., Coops, N.C., Nielsen, S.E., 2018. Functional macronutritional generalism in a large omnivore, the brown bear. Ecology and evolution. 8(4), 2365-2376.

[61] Robbins, C.T., Ben-David, M., Fortin, J.K., Nelson, O.L., 2012. Maternal condition determines birth date and growth of newborn bear cubs. J. Mammal. 93, 540-546.

[62] Albrecht, J., Bartoń, K.A., Selva, N., Sommer, R.S., Swenson, J.E., Bischof, R., 2017. Humans and climate change drove the Holocene decline of the brown bear. Scientific reports. 7(1), 10399.

[63] Schloss, C.A., Nuñez, T.A., Lawler, J.J., 2012. Dispersal will limit ability of mammals to track climate change in the Western Hemisphere. Proceedings of the National Academy of Sciences. 109(22), 8606- 8611.

[64] Velásquez-Tibatá, J., Salaman, P., Graham, C.H., 2013. Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia. Regional Environmental Change. 13(2), 235-248.



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