Elements of metacommunity structure in Amazonian Zygoptera among streams under different spatial scales and environmental conditions

Abstract

An important aspect of conservation is to understand the founding elements and characteristics of metacommunities in natural environments, and the consequences of anthropogenic disturbance on these patterns. In natural Amazonian environments, the interfluves of the major rivers play an important role in the formation of areas of endemism through the historical isolation of species and the speciation process. We evaluated elements of metacommunity structure for Zygoptera (Insecta: Odonata) sampled in 93 Amazonian streams distributed in two distinct biogeographic regions (areas of endemism). Of sampled streams, 43 were considered to have experienced negligible anthropogenic impacts, and 50 were considered impacted by anthropogenic activities. Our hypothesis was that preserved (“negligible impact”) streams would present a Clementsian pattern, forming clusters of distinct species, reflecting the biogeographic pattern of the two regions, and that anthropogenic streams would present random patterns of metacommunity, due to the loss of more sensitive species and dominance of more tolerant species, which have higher dispersal ability and environmental tolerance. In negligible impact streams, the Clementsian pattern reflected a strong biogeographic pattern, which we discuss considering the areas of endemism of Amazonian rivers. As for communities in human‐impacted streams, a biotic homogenization was evident, in which rare species were suppressed and the most common species had become hyper‐dominant. Understanding the mechanisms that trigger changes in metacommunities is an important issue for conservation, because they can help create mitigation measures for the impacts of anthropogenic activities on biological communities, and so should be expanded to studies using other taxonomic groups in both tropical and temperate systems, and, wherever possible, at multiple spatial scales.

Historical processes constrain metacommunity structure by shaping different pools of invertebrate taxa within the Orinoco basin

“…Taken collectively, the above‐mentioned findings suggest that past historical events shaped taxon distribution in the way they shaped the distribution and physiographic features of the ecoregional types across the Orinoco basin (e.g., Goosen, ; van der Hammen, ; Hoorn et al, ; Hughes & Eastwood, ). Several studies have indicated that a concordance between species pools and ecoregion (or biogeographical region) distributions provides indirect evidence of the effects of historical events on present‐day biodiversity patterns (Brasil et al, ; Hazzi, Moreno, Ortiz‐Movliav, & Palacio, ; Presley & Willig, ).…”

“…As these ecoregional features do not always match the extension of the stream networks, this scenario provides the opportunity to test the influence of the potential occurrence of different pools of species metacommunity structure. The few comparable studies carried out in the Tropics have indicated the occurrence of several pools of species across the region (Benito et al, ; Brasil, Vieira, Oliveira‐Junior, Dias‐Silva, & Juen, ; Datry et al, ). However, to our knowledge only one has addressed how the occurrence of different pools of species may shape the structure of phytoplankton metacommunities (Benito et al, ).…”

Drivers of regional and local diversity of Amazonian stream Odonata

“…Habitat integrity summarises coverage of riparian forest, the land use adjacent to the riparian zone and some characteristics of the stream channel, such as bank structure of rivers (Hannaford et al ., ; Roy et al ., ; Nessimian et al ., ), and can be interpreted as forest cover (Nessimian et al ., ). Indeed, this variable is an important predictor of Zygoptera species richness and composition in Amazonia (Monteiro Júnior et al ., ; Oliveira‐Junior et al ., ; Brasil et al ., ) and other Brazilian biomes (De Marco et al ., ; Mendes et al ., ). With increasing forest cover, the dominance of damselfly species increases, while the dominance of dragonflies decreases (De Marco et al ., ).…”

“…Although commonly considered a homogeneous environment, Amazonia is in fact divided in distinct macroclimatic zones within the tropical climate, from superhumid in the western Amazon due to the strong influence of the Andes, to progressively subhumid in central Amazon, and even presenting dry winters at the southern and eastern Amazon basin (Peel et al ., ). These differences in macroclimatic patterns increase the regional species richness of Odonata by increasing the spatial turnover of species (Brasil et al ., ) that occupy distinct physiological niches (Collins & McIntyre, ; Amundrud et al ., ). Indeed, they explain the strong climatic effects on the species richness of the biogeographical modules, which are thought to capture the determinants of geographic species ranges.…”

Spatial, biogeographic and environmental predictors of diversity in Amazonian Zygoptera

“…The taxonomic and phylogenetic diversity of some animal groups, such as primates and birds, is known to be strongly related to the formation and structure of these interfluves (Wallace, 1854;Ayres & Clutton-Brock, 1992;Ribas et al, 2012;Pomara et al, 2014). In the specific case of the Odonata, at large spatial scales, the distribution of species of the Zygoptera is closely related to areas of endemism (Brasil et al, 2017). This is because the Zygoptera have a reduced capacity for dispersal, making the major Amazonian rivers important geographical barriers to their dispersion, and thus over time, forming areas of endemism corresponding to the interfluves of these major rivers (Juen & De Marco, 2012).…”