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Abstract AimAlpine ecosystems differ in area, macroenvironment and biogeographical history across the Earth, but the relationship between these factors and plant species richness is still unexplored. Here, we assess the global patterns of plant species richness in alpine ecosystems and their association with environmental, geographical and historical factors at regional and community scales. LocationGlobal. Time periodData collected between 1923 and 2019. Major taxa studiedVascular plants. MethodsWe used a dataset representative of global alpine vegetation, consisting of 8,928 plots sampled within 26 ecoregions and six biogeographical realms, to estimate regional richness using sample‐based rarefaction and extrapolation. Then, we evaluated latitudinal patterns of regional and community richness with generalized additive models. Using environmental, geographical and historical predictors from global raster layers, we modelled regional and community richness in a mixed‐effect modelling framework. ResultsThe latitudinal pattern of regional richness peaked around the equator and at mid‐latitudes, in response to current and past alpine area, isolation and the variation in soil pH among regions. At the community level, species richness peaked at mid‐latitudes of the Northern Hemisphere, despite a considerable within‐region variation. Community richness was related to macroclimate and historical predictors, with strong effects of other spatially structured factors. Main conclusionsIn contrast to the well‐known latitudinal diversity gradient, the alpine plant species richness of some temperate regions in Eurasia was comparable to that of hyperdiverse tropical ecosystems, such as the páramo. The species richness of these putative hotspot regions is explained mainly by the extent of alpine area and their glacial history, whereas community richness depends on local environmental factors. Our results highlight hotspots of species richness at mid‐latitudes, indicating that the diversity of alpine plants is linked to regional idiosyncrasies and to the historical prevalence of alpine ecosystems, rather than current macroclimatic gradients.
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Regional species gains outpace losses across North American continental shelf regions
Abstract AimAlthough species richness globally is likely to be declining, patterns in diversity at the regional scale depend on species gains within new habitats and species losses from previously inhabited areas. Our understanding of the processes associated with gains or losses remains poor, including whether these events exhibit immediate or delayed responses to environmental change. LocationThe study focuses on nine temperate marine ecosystems in North America. Time periodThe study period varies by region, but overall encompasses observations from 1970 to 2014. Major taxa studiedWe identified regional gains and losses for 577 marine fish and invertebrate species. MethodsFrom a total of 166,213 sampling events from bottom trawls across North America that informed 17,997 independent observations of species gains and losses, we built generalized linear mixed effects models to test whether lagged temperature can explain instances of gains and losses of marine fishes and invertebrates in North American continental shelf habitats. ResultsWe found that gains were less likely in years with high seasonality, consistent with seasonal extremes as a strong constraint on species occurrence. Losses were also negatively associated with high seasonality, but the response was delayed by 3 years. Main conclusionsEnvironmental conditions play a role in species occupancy across diverse temperate marine ecosystems. Immediate gains paired with delayed losses can drive transient increases in species richness during times of environmental change. Identifying the dynamics behind regional species gains and losses is an important step towards prediction of biodiversity changes across ecosystems.
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- PAR ID:
- 10419887
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Global Ecology and Biogeography
- Volume:
- 32
- Issue:
- 7
- ISSN:
- 1466-822X
- Page Range / eLocation ID:
- p. 1205-1217
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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