Local-scale environmental filtering shape plant taxonomic and phylogenetic diversity in an isolated Amazonian tepui (Tepequém table mountain)

Abstract

Understanding how environmental drivers induce changes in plant composition and diversity across evolutionary time can provide important insights into the mechanisms of community assembly. We evaluated how taxonomic and phylogenetic diversity and structure of plant communities change along a local-scale edaphic and topographic gradient in the Tepequém table mountain, Brazilian Amazon. We selected three phytophysiognomies along the altitudinal gradient: Open Rupestrian Grassland, Shrubby Rupestrian Grassland, and Forest. We compared community composition and taxonomic and phylogenetic diversity between phytophysiognomies, and we tested regression linear effect models to investigate the effect of altitude and soil properties on taxonomic and phylogenetic diversity. The highest species richness and phylogenetic diversity were found at lower elevation for Forest. Mean pairwise phylogenetic distance, mean nearest taxon phylogenetic distance, and all standardised phylogenetic metrics were signi cantly lower in Shrubby Rupestrian Grassland. This phytophysiognomy showed phylogenetic clustering. Forest showed a cluster pattern when only terminal nodes are considered and random dispersion to deep phylogenetic nodes. Open Rupestrian Grassland also showed random phylogenetic structure. The regression analyses showed that species richness and different phylogenetic diversity metrics were explained by altitude and soil properties. However, standardised metrics were not explained by these environmental variables. Comprehensive studies including the role of environmental drivers in plant evolutionary history along the altitudinal gradient are necessary for explaining community assembly patterns and provide additional information for conservation planning.

Phylogenetic diversity and structure in moist and dry upland forests in the semi-arid region of Brazil

“…This is congruent with the importance of higher water availability and moderate temperatures as essential drivers of increased phylogenetic diversity in upland forests (Qian et al, 2014;Zhang et al, 2020;Cisneros et al, 2021;Tolmos et al, 2022). Although elevation is also an essential variable influencing the patterns of phylogenetic diversity and structure of upland forests (Mattos et al, 2019;Campos et al, 2021, Campos et al 2022b, its effect on phylogenetic diversity and structure was less pronounced than precipitation and temperature in our study. Since elevation directly affects local environmental conditions (e.g., temperature, atmospheric pressure, soils), its impact on biological communities is indirect (Körner et al, 2017), thus possibly masking its actual effects in our analysis.…”

“…In the Neotropics, these abiotic filters stand out as significant drivers of shifts in taxonomic diversity patterns among different plant communities established in uplands, such as Andean forests (Cuesta et al, 2017), Tepuis (Campos et al, 2022a), Inselbergs (Pinto-Junior et al, 2020), Páramos (Campos et al, 2018;Neri et al, 2017), and Caatinga Uplands (Santos et al, 2007a;Ramos et al, 2020;Diniz et al, 2021). Recent studies also indicate that these abiotic filters have a strong relationship with phylogenetic diversity and structure patterns observed in Neotropical upland ecosystems (Mattos et al, 2019;Campos et al, 2021Campos et al, , 2022bCisneros et al, 2021).…”

Phylogenetic and functional community structure of trees in a seasonal tropical forest

“…Our results showed that elevational habitats exhibit significant differences in local scale of phylogenetic structures. The results sustain that local scale variations can promote phylogenetics diversity (Kembel & Hubbell 2006;Morelli et al 2021;Campos et al 2022), showing that phylogenetic diversity and structure could present a altitudinal patterns at local scale topographic gradient (Kembel & Hubbell 2006;Morelli et al 2021), the increase of altitude tend to decrease PD (Morelli et al 2021). Lower elevation areas showed higher phylogenetic diversity and higher distances between species and lower distances between species of closely related taxa (Morelli et al 2021).…”

Insights into dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) distribution along an elevational gradient in a tepui table-top mountain in the Brazilian Amazon

“…Of the 14 species we sampled, only two (D. nisus and an unidentified Canthon species) were found in the highlands, and both were recorded exclusively at those elevations. The Tepequém tepui comprises two marked vegetation structures, one from the lowlands and intermediate elevation (tropical rainforest) and one from the highlands (savannah, rupestrian grassland; Prance 1996; Campos et al 2022), and according to our samples, dung beetle species composition appears to respond to this bimodal vegetational pattern. Interestingly, D. nisus, a broadly distributed species in Brazilian open vegetation (e.g., the Cerrado savanna and Caatinga dry forest, Brazil; Cassenote et al 2020), was recorded in the highlands.…”