A multi-faceted comparative perspective on elevational beta-diversity: the patterns and their causes

Abstract

The observed patterns and underlying mechanisms of elevational beta-diversity have been explored intensively, but multi-dimensional comparative studies remain scarce. Herein, across distinct beta-diversity components, dimensions and species groups, we designed a multi-faceted comparative framework aiming to reveal the general rules in the observed patterns and underlying causes of elevational beta-diversity. We have found that: first, the turnover process dominated altitudinal patterns of species beta-diversity ( β sim > β sne ), whereas the nestedness process appeared relatively more important for elevational trait dissimilarity ( β funcsim < β funcsne ); second, the taxonomic turnover was relative higher than its phylogenetic and functional analogues ( β sim > β phylosim / β funcsim ), conversely, nestedness-resultant trait dissimilarity tended to be higher than the taxonomic and phylogenetic measures ( β funcsne > β sne / β phylosne ); and third, as elevational distance increased, the contradicting dynamics of environmental filtering and limiting similarity have jointly led the elevational patterns of beta-diversity, especially at taxonomic dimension. Based on these findings, we infer that the species turnover among phylogenetic relatives sharing similar functional attributes appears to be the main cause of shaping the altitudinal patterns of multi-dimensional beta-diversity. Owing to the methodological limitation in the randomization approach, currently, it remains extremely challenging to distinguish the influence of the neutral process from the offset between opposing niche-based processes. Despite the complexities and uncertainties during species assembling, with a multi-dimensional comparative perspective, this work offers us several important commonalities of elevational beta-diversity dynamics.

Multidimensional amphibian diversity and community structure along a 2 600 m elevational gradient on the eastern margin of the Qinghai-Tibetan Plateau

“…Additionally, deterministic (e.g., environmental filtering and competitive exclusion) and stochastic processes (e.g., colonization, extinction, and ecological drift) can simultaneously drive community structure ( Chase, 2010 ), with inconsistent importance among these forces. Moreover, due to the methodological limitations in randomization approaches, stochastic processes remain difficult to be distinguished from the offset between deterministic niche-based processes ( Du et al, 2021 ). Given this, more controlled experiments or manipulations in further studies are required to evaluate the relative importance of these processes.…”

“…Notably, a decline in both FD and PD is often detected with elevation ( Dehling et al, 2014 ; Hanz et al, 2019 ). However, consensus about the generality of elevational patterns and the importance of deterministic processes underlying biodiversity patterns in montane systems remains elusive ( Du et al, 2021 ; Jarzyna et al, 2021 ; Montaño-Centellas et al, 2020 ; Mori et al, 2013 ).…”

“…However, community assembly processes with elevation are likely to be complex and show different trends, including clustering at mid elevations and overdispersion at low and high elevations ( Jarzyna et al, 2021 ), or may exhibit a single process ( Montaño-Centellas et al, 2020 ). When investigating phylogenetic and functional structures of communities, there could be an offset between two processes along elevational gradients (e.g., weakened environmental filtering with strengthened competition; Figure 1B ) ( Du et al, 2021 ; Jiang et al, 2018 ).…”

Spatiotemporal maintenance of flora in the Himalaya biodiversity hotspot: Current knowledge and future perspectives

“…Beta diversity, which quantifies variability in community composition among sampling units (Whittaker, 1960 ), is increasingly becoming important for understanding the mechanisms of biodiversity maintenance (e.g., Baselga, 2010 ; Condit et al., 2002 ; Du et al., 2021 ). Although beta diversity patterns of plant communities in the Himalaya have received less attention than alpha diversity, previous studies indicate that topographic (e.g., slope orientation and elevation), environmental (e.g., soil properties), and anthropogenic (land use) factors are the key determinants of beta diversity patterns in the region (Paudel & Vetaas, 2014 ; Rawat et al., 2020 ).…”

Family Legacy: Depicting Diversity-Elevation Relationships of Tropical Tree Communities

“…It is expected that species dissimilarity between communities increases with the geographical distance between them ( In line with our rst hypothesis, species and phylogenetic beta diversity were similar, whilst species turnover was higher than phylogenetic, across different elevations. On one hand, similar patterns of species and phylogenetic beta diversity found along environmental gradients can be associated with the conservatism of functional attributes (Du et al 2021). On the other hand, species turnover was higher in relation to phylogenetic, indicating species diversi cation observed in species-level, rather than in genus or family levels.…”