Elevational gradients of species richness, community structure, and niche occupation of tropical rove beetles (Coleoptera: Staphylinidae: Steninae) across mountain slopes in Northern Thailand

Abstract

We evaluated patterns of species richness, heterogeneity, niche occupation, and community structuring/similarity of staphylinid beetles of the subfamily Steninae across a 2500-m elevational gradient of a tropical mountain area in Northern Thailand. Predaceous Steninae were collected from a variety of habitat types. Increasing Sørensen dissimilarity with increasing elevation was explained by both species turnover (especially across the lower elevational zones) and declining numbers of species (especially across elevations > 1400 m). Unlike the strong decline of the number of species with increasing elevation, species density (i.e., total number of species divided by the number of collection sites at the respective elevational zone) showed a much smoother decline suggesting that the negative gradient in the number of species was superimposed by a land-area effect inherent in mountain shape. In both the litter-inhabiting species and waterfall-associated species, the numbers of species showed a mid-elevational peak. Species frequency was positively correlated to both elevational ("Dianous" and Stenus) and habitat niche width (Stenus only). Stenus showed high interspecific variety of wide to narrow niche widths for both elevation and habitat. Numbers of Palearctic and Oriental species deviated from statistical expectation, suggesting that climate niche conservatism has played a role in their elevational distribution. The distributional patterns of "Dianous" beetles, with their strong hygrobiont preferences associated with rocks in running water and waterfalls, are potentially explained by source-sink dynamics along mountain streams.

Diversity and phylogenetic community structure across elevation during climate change in a family of hyperdiverse neotropical beetles (Staphylinidae)

“…For full details regarding sampling please see Smith et al (2014), and in particular Appendix ECOG-00631 at <www.oikosoffice.lu.se/appendix/ecog-00631>. Such a sampling strategy, directed at many taxa, will clearly yield fewer samples of any one taxon than if sampling were to be conducted with a direct search with a focus on particular group (Betz et al 2020). All samples were preserved in 95% ethanol upon collection and later preserved at −20°C.…”

Elevational boundaries influence richness patterns at large spatial scales evinced by madicolous insects of the Brazilian Atlantic Forest

“…The influence of area on richness patterns is one of the few laws in ecology (Dodds, 2009), thus the effects of the area should be regarded in studies dealing with spatial variation in richness. However, few studies have considered the area effect in altitudinal patterns of richness (Betz et al, 2020;McCain, 2007;Romdal & Grytnes, 2007). Due to the conical shape of most mountains (Körner, 2000;Lomolino, 2001), species richness tends to increase towards the base where the available area is larger.…”

How mountains and elevations shape the spatial distribution of beetles in Peninsular Malaysia

“…This coincides with the hypothesis that climate niche conservatism plays a role in the elevational species distributions in tropical montane ecosystems. Apart from this ecological explanation, historical factors, such as past climate change and biogeographical history, immigration, priority effects, and evolutionary mechanisms should also be considered, since these factors are regularly interwoven 47 . Across these studied mountains, a crucial aspect that remains to be evaluated is current levels of connectivity among them, and what levels of change in this variable are acceptable for the future conservation of biodiversity.…”

“…Endemic species contributed most to single mountain species richness in this study, likely due to a number of reasons including the biogeographical history of the mountain, climatic influences, and dispersal ability of species and their niche preferences. The climatic niche widths will restrict the species within a narrow range of elevations, leading to increased isolation, which promotes endemism and ultimately speciation 47 . We detected high biotic heterogeneity among all mountains, where comparison of Gunung Inas with Cameron Highland, Chamah Highland, Gunung Benom, Gunung Angsi, and Gunung Besar Hantu have high turnover values, which means that the identity of the species differs among Gunung Inas and the other named mountains.…”

“…This coincides with the hypothesis that climate niche conservatism plays a role in the elevational species distributions in tropical montane ecosystems. Apart from this ecological explanation, historical factors, such as past climate change and biogeographical history, immigration, priority effects, and evolutionary mechanisms should also be considered, since these factors are regularly interwoven 47 .…”