Drivers of regional and local diversity of Amazonian stream Odonata

Abstract

Large Amazonian rivers may act as dispersal barriers for animals with low dispersal abilities, limiting their distribution to certain interfluves. Consequently, the distribution of these taxa would be less affected by macroclimatic gradients. Conversely, high‐dispersal taxa would be less constrained by large rivers and may track suitable climates. We evaluate whether Zygoptera and Anisoptera, two Odonata suborders with different dispersal abilities, show differences in distribution patterns across Amazonian interfluves. We further assess the relative importance of macroclimatic and habitat factors in their community assembly. We used network modularity analyses to identify biogeographic species pools and spatial buffers to define metacommunity species pools. Then, we used structural equation models to estimate the relative importance of multi‐scale factors on species richness patterns. Zygoptera communities are more similar in species composition within than between interfluves, suggesting that large Amazonian rivers indeed limit the distribution of Zygoptera species. Conversely, the distribution of Anisoptera extends across Amazonian interfluves. Seasonality has a strong positive effect on Zygoptera and Anisoptera richness across scales. In addition, habitat integrity is negatively correlated with the regional species richness and abundance of Anisoptera and positively correlated with Zygoptera local richness. The contrasting effects of habitat integrity on Anisoptera and Zygoptera suggest that the former is favored in open habitats, whereas the latter is so in forests. Despite these differences, both suborders appear to follow similar community assembly mechanisms in Amazonia, with a strong climatic control across scales and an effect of habitat filters on local communities.

Metacommunity patterns of Amazonian Odonata: the role of environmental gradients and major rivers

“…The composition of Odonata metacommunities across interfluves in Amazonia emerges mainly from a combination of Amazonian major rivers, macroclimate and habitat integrity environment (and space, in the case of Anisoptera) in Amazonia. These findings are consistent with previous studies showing that Amazonian biogeography (Juen & Marco, 2012; Brasil et al, 2017; Alves-Martins et al, 2018) and climate are the main drivers for Odonata metacommunities at coarser spatial scales (Chovanec et al, 2015; Bried et al, 2015). Our results also confirm that intactness of riparian forest is important for Amazonian stream Odonata communities (De Marco, Batista & Cabette, 2015; De Marco et al., 2015; Miguel et al, 2017; Alves-Martins et al, 2018) and distinct Amazonian districts show distinct community composition, which has important implication for conservation.…”

“…This finding is consistent with the results of Brasil et al (2017), who found a Clementsian pattern for Zygoptera metacommunities in non-impacted streams at Belém and Tapajós interfluves, and Alves-Martins et al (2018), who found distinct species compositions across the interfluves of major Amazonian rivers. These results suggest that the Clementsian pattern in Amazonian Odonata may be related to the historical isolation of communities generated by the emergence of large rivers, which means that the edges of Odonata species ranges coincide with the limits of the interfluves (Juen & De Marco, 2012; Brasil et al, 2017; Alves-Martins et al, 2018). These distribution patterns follow the predictions of the theory of isolation by rivers in Amazonia, initially proposed by Wallace (1852), and that has been corroborated for other organisms (e.g., Cracraft, 1985; Bates, Haffer & Grismer, 2004).…”

“…Indeed, annual mean temperature, habitat integrity, annual precipitation and the biogeographic region (i.e., interfluve) in which the metacommunity is placed are the main correlates of the spatial structure of Odonata metacommunities across the Amazonian interfluves. This suggests that both Zygoptera and Anisoptera metacommunities are arranged in subsets of communities along environmental gradients separated by the major Amazonian rivers (Alves-Martins et al, 2018; Brasil et al, 2017). However, these results are less consistent within interfluves, and only partially support our initial hypothesis.…”

Sampling efficiency of a protocol to measure Odonata diversity in tropical streams

“…Richness was not associated with the different spatial efforts employed, with no increase in richness as the area of sampled transects increased. Dragonflies are flying organisms with a high dispersal ability [ 10 ]. Perhaps the difference between 100, 200 and 300 meters is not enough to capture the change in species richness due to the easy dispersion of these insects along the stream, making it expensive to sample spaces larger than 100 meters.…”

Spatial partitioning of perching on plants by tropical dung beetles depends on body size and leaf characteristics: a sit‐and‐wait strategy for food location

“…Here, we investigated the relationship between dung beetle body size, perch height and other plant traits in a tropical forest. We evaluated potential perching preferences and dung beetle-plant networks following similar approaches to those used for other tropical arthropods by de de Araújo and Daud (2018) and Alves-Martins et al (2019). Our research questions were: Do large beetles perch on higher plants than smaller beetles?…”