Climate and geographic distance are more influential than rivers on the beta diversity of passerine birds in Amazonia

Abstract

Variation in the spatial structure of communities in terms of species composition (beta diversity) is affected by different ecological processes, such as environmental filtering and dispersal limitation. Large rivers are known as barriers for species dispersal (riverine hypothesis) in tropical regions. However, when organisms are not dispersal limited by geographic barriers, other factors, such as climatic conditions and geographic distance per se, may affect species distribution. In order to investigate the relative contribution of major rivers, climate and geographic distance on Passeriformes beta diversity, we divided Amazonia into 549 grid cells (1° of latitude and longitude) and obtained data of species occurrence, climate and geographic position for each cell. Beta diversity was measured using taxonomic, phylogenetic and functional metrics of composition. The influence of climatic variables, geographic distance and rivers on these metrics was tested using regression analyses. Passerine beta diversity is characterized mainly by the change in species taxonomic identity and in phylogenetic lineages across climatic gradients and over geographic distance. However, species with similar traits are found throughout the entire Amazonia. The size of rivers was proportional to their effect on species composition. However, climate and geographic distance are relatively more important than rivers for Amazonian taxonomic and phylogenetic species composition.

The role of environmental filtering, geographic distance and dispersal barriers in shaping the turnover of plant and animal species in Amazonia

“…Variance in species composition captured by the first PCoA axis-birds: 0.09; fishes (high disp): 0.19; fishes (low disp): 0.18; bats: 0.14; dominant ants (bait): 0.09; mobile-forager ants (pitfall): 0.08; cryptic ants (Winkler): 0.14; termites: 0.10; butterflies: 0.12; ferns ? lycophytes: 0.13; gingers: 0.13; palms: 0.26 Silva et al 2005a, b;Boubli et al 2015;Silva et al 2019;Maximiano et al 2020), climate and geographic distance (Dambros et al 2017;Fluck et al 2020). We found that soil conditions and geographic distance were important predictors for all taxonomic groups, but their relative importance varied among taxonomic groups, and bellow we discuss the congruence and discrepancies among biological groups in their response to these factors.…”

“…Because the Amazon river is the largest and oldest river in the region (Hoorn et al 2010) and has been hypothesized to have stronger effects on species composition than other rivers (e.g. Fluck et al 2020), we expected differences between regions separated by the Amazon river to be stronger than between other regions. We present results from the Tukey test with this distinction (see ''Results'' section).…”

Identifying the Drivers of Spatial Taxonomic and Functional Beta-Diversity of British Breeding Birds

“…The effect of dispersal on spatial beta-diversity can be assessed through the analysis of the geographic distance between sites, while the effect of environment can be tested by evaluating measures of habitat and land use types (hereafter 'land use') and climate (Luck et al, 2013;Wieczynski et al, 2019;Fluck et al, 2020). However, due to the spatial structuring of environmental gradients (i.e., a distance decay in environmental conditions), it is difficult to partition the unique effects of each (Leibold and Chase, 2017).…”

Avian community composition affects ornithophilic mosquito and avian malaria turnover across an interfluvial system in southern Amazonia

“…The Amazon region is the result of pervasive biogeographical processes, with large rivers acting as geographic barriers to some taxa (Ribas et al 2012, Dias‐Terceiro et al 2015, Naka and Brumfield 2018) and promoting enough isolation to affect community assembly (Fluck et al 2020). There is evidence that large Amazonian rivers can affect bird composition (Oliveira et al 2017) and haemosporidian diversification (Fecchio et al 2018b), however, some insects may not be constrained by riverine barriers due to their dispersion capability (Dambros et al 2017).…”

“…The role of the interfluves of the Amazon basin in the community composition of vertebrate taxa has been well studied (Wallace 1852, Cracraft 1985). However, identifying the different dimensions responsible for variation in community composition (β‐diversity) may uncover the effects of riverine barriers on this host–vector–parasite system, and also reveal previously unknown biological interactions within this system (Clark and Clegg 2017, Fluck et al 2020). In this sense, analyzing different dimensions of β‐diversity such as the incorporation of functional trait differences between communities (Villéger et al 2010) can provide information regarding differences in the evolutionary history between communities (Leprieur et al 2012).…”