Effects of contemporary environment and Quaternary climate change on drylands plant diversity differ between growth forms

Abstract

Previous studies on large‐scale patterns in plant richness and underlying mechanisms have mostly focused on forests and mountains, while drylands covering most of the world's grasslands and deserts are more poorly investigated for lack of data. Here, we aim to 1) evaluate the plant richness patterns in Inner Asian drylands; 2) compare the relative importance of contemporary environment, historical climate, vegetation changes, and mid‐domain effect (MDE); and 3) explore whether the dominant drivers of species richness differ across growth forms (woody vs herbaceous) and range sizes (common vs rare). Distribution data and growth forms of 13 248 seed plants were compiled from literature and species range sizes were estimated. Generalized linear models and hierarchical partitioning were used to evaluate the relative contribution of different factors. We found that habitat heterogeneity strongly affected both woody and herbaceous species. Precipitation, climate change since the mid‐Holocene and climate seasonality dominated herbaceous richness patterns, while climate change since the Last Glacial Maximum dominated woody richness patterns. Rare species richness was strongly correlated with precipitation, habitat heterogeneity and historical climatic changes, while common species richness was strongly correlated with MDE (woody) or climate seasonality (herbaceous). Temperature had little effects on the species richness patterns of all groups. This study represents the first evaluation of the large‐scale patterns of plant species richness in the Inner Asian drylands. Our results suggest that increasing water deficit due to anthropogenic activities combined with future global warming may increase the extinction risk of many grassland species. Rare species (both herbaceous and woody) may face severe challenges in the future due to increased habitat destruction caused by urbanization and resource exploitation. Overall, our findings indicate that the hypotheses on species richness patterns based on woody plants alone can be insufficient to explain the richness patterns of herbaceous species.

The Importance of Including Soil Properties When Disentangling the Drivers of Species Richness: The Case of the Alpine Genus Saxifraga L. in China

“…Therefore, HHM can play a role in refugium when climate change events happened. Previous studies found that habitat heterogeneity is also the primary determinant of spatial variation of plant species richness in drylands (Liu et al, 2019), Tibetan Plateau (Mao et al, 2013), and European mountains (Svenning and Skov, 2004;Svenning et al, 2006). These results are probably caused by the refugia effects, subsequent speciation events, and limited dispersals for species in the mountains.…”

Isolation and Molecular Characterization of a Gene Coding for Defensin From an Egyptian Maize Hybrid (Sc 168)

“…Plant diversity displays distinct large-scale geographic patterns, which in turn are determined by late Quaternary and contemporary climatic conditions, both together and independently (e.g., Svenning, 2003;Kreft and Jetz, 2007;Sommer et al, 2010;Sandel et al, 2011;Wang et al, 2012a;Liu et al, 2018). A core hypothesis of biodiversity is that contemporary climates determine current plant diversity (O'brien et al, 2000;Ackerly et al, 2010;Kimball et al, 2010).…”

Effects of current climate, paleo-climate, and habitat heterogeneity in determining biogeographical patterns of evergreen broad-leaved woody plants in China

“…Among the influential factors considered, current climate, paleo-climate, and habitat heterogeneity are the most frequently cited explanations for the biodiversity patterns observed (Liu et al, 2018). Whether diversity patterns are caused by the current climate or by historical factors has been discussed for a long time.…”