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- Barrio, I. C., et al.
(author)
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Biotic interactions mediate patterns of herbivore diversity in the Arctic
- 2016
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In: Global Ecology and Biogeography. - : Wiley-Blackwell. - 1466-822X .- 1466-8238. ; 25:9, s. 1108-1118
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Journal article (peer-reviewed)abstract
- Aim: Understanding the forces shaping biodiversity patterns, particularly for groups of organisms with key functional roles, will help predict the responses of ecosystems to environmental changes. Our aim was to evaluate the relative role of different drivers in shaping the diversity patterns of vertebrate herbivores, a group of organisms exerting a strong trophic influence in terrestrial Arctic ecosystems. This biome, traditionally perceived as homogeneous and low in biodiversity, includes wide variation in biotic and physical conditions and is currently undergoing major environmental change. Location: The Arctic (including the High Arctic, Low Arctic and Subarctic) MethodsWe compiled available data on vertebrate (birds and mammals) herbivore distribution at a pan-Arctic scale, and used eight variables that represent the most relevant hypotheses for explaining patterns of species richness. We used range maps rasterized on a 100kmx100km equal-area grid to analyse richness patterns of all vertebrate herbivore species combined, and birds and mammalian herbivores separately. Results: Overall, patterns of herbivore species richness in the Arctic were positively related to plant productivity (measured using the normalized difference vegetation index) and to the species richness of predators. Greater species richness of herbivores was also linked to areas with a higher mean annual temperature. Species richness of avian and mammalian herbivores were related to the distance from the coast, with the highest avian richness in coastal areas and mammalian richness peaking further inland. Main conclusions: Herbivore richness in the Arctic is most strongly linked to primary productivity and the species richness of predators. Our results suggest that biotic interactions, with either higher or lower trophic levels or both, can drive patterns of species richness at a biome-wide scale. Rapid ongoing environmental changes in the Arctic are likely to affect herbivore diversity through impacts on both primary productivity and changes in predator communities via range expansion of predators from lower latitudes.
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| 2. |
- Williamson, S.N., et al.
(author)
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Evidence for elevation-dependent warming in the St. Elias Mountains, Yukon, Canada
- 2020
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In: Journal of Climate. - : American Meteorological Society. - 0894-8755 .- 1520-0442. ; 33:8, s. 3253-3269
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Journal article (peer-reviewed)abstract
- The climate of high midlatitude mountains appears to be warming faster than the global average, butevidence for such elevation-dependent warming (EDW) at higher latitudes is presently scarce. Here, we use acomprehensive network of remote meteorological stations, proximal radiosonde measurements, downscaledtemperature reanalysis, ice cores, and climate indices to investigate the manifestation and possible drivers ofEDW in the St. Elias Mountains in subarctic Yukon, Canada. Linear trend analysis of comprehensivelyvalidated annual downscaled North American Regional Reanalysis (NARR) gridded surface air temperaturesfor the years 1979–2016 indicates a warming rate of 0.0288Ca21 between 5500 and 6000mabovemeansea level (MSL), which is ;1.6 times larger than the global-average warming rate between 1970 and 2015.The warming rate between 5500 and 6000m MSL was ;1.5 times greater than the rate at the 2000–2500mMSL bin (0.0198Ca21), which is similar to the majority of warming rates estimated worldwide over similarelevation gradients. Accelerated warming since 1979, measured by radiosondes, indicates a maximum rateat 400 hPa (;7010mMSL). EDWin the St. Elias region therefore appears to be driven by recent warmingof the free troposphere. MODIS satellite data show no evidence for an enhanced snow albedo feedbackabove 2500m MSL, and declining trends in sulfate aerosols deposited in high-elevation ice cores suggest amodest increase in radiative forcing at these elevations. In contrast, increasing trends in water vapor mixingratio at the 500-hPa level measured by radiosonde suggest that a longwave radiation vapor feedback iscontributing to EDW.
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