Community Assembly of Adult Odonates in Tropical Streams: An Ecophysiological Hypothesis

Abstract

Community assembly theory is founded on the premise that the relative importance of local environmental processes and dispersal shapes the compositional structure of metacommunities. The species sorting model predicts that assemblages are dominated by the environmental filtering of species that are readily able to disperse to suitable sites. We propose an ecophysiological hypothesis (EH) for the mechanism underlying the organization of species-sorting odonate metacommunities based on the interplay of thermoregulation, body size and the degree of sunlight availability in small-to-medium tropical streams. Due to thermoregulatory restrictions, the EH predicts (i) that larger species are disfavored in small streams and (ii) that streams exhibit a nested compositional pattern characterized by species’ size distribution. To test the EH, we evaluate the longitudinal distribution of adult Odonata at 19 sites in 1st- to 6th-order streams in the Tropical Cerrado of Brazil. With increasing channel width, the total abundance and species richness of Anisoptera increased, while the abundance of Zygoptera decreased. The first axis of an ordination analysis of the species abundance data was directly related to channel width. Mean and maximum thorax size are positively correlated to channel width, but no relationship was found for the minimum thorax size, suggesting that there is no lower size constraint on the occurrence of these species. Additionally, a nested compositional pattern related to body size was observed. Our results support the EH and its use as an ecological assembly rule based on abiotic factors. Forest cover functions as a filter to determine which species successfully colonize a given site within a metacommunity. As a consequence, the EH also indicates higher treats for small-bodied zygopterans in relation to the loss of riparian forests in tropical streams.

The impacts of habitat disturbance on adult and larval dragonflies (Odonata) in rainforest streams in Sabah, Malaysian Borneo

“…oil palm = 9 °C). Temperature‐sensitive species could potentially be out‐competed by larger gap‐loving species if forest is cleared (De Marco Júnior, Batista & Cabette, ). Many of the species that were present in oil palm sites were large‐bodied, sun‐loving, cosmopolitan Anisoptera, including many within the Libellulidae family.…”

Macrophytes promote aquatic insect conservation in artificial ponds

“…Ponds within the agricultural mosaic contribute to regional biodiversity by adding species not found in other habitats (Biggs, Corfield, Walker, Whitfield, & Williams, 1994;Biggs, von Fumetti, & Kelly-Quinn, 2017;Declerck et al, 2006;Ruggiero, Céréghino, Figuerola, Marty, & Angélibert, 2008) and by supporting diverse communities of aquatic organisms (Júnior, Batista, & Cabette, 2015;Oertli et al, 2002;Raebel et al, 2012;Williams et al, 2004).…”

Determinant landscape‐scale factors on pond odonate assemblages

“…Studies dealing with odonate assemblages and conservation usually consider damselflies and dragonflies separately, when considering species composition, species richness and population abundance (De Marco J unior, Batista, & Cabette, 2015;Kietzka et al, 2015;Pryke, Samways, & De Saedeleer, 2015;Simaika, Samways, & Frenzel, 2016). Due to their differences in size, behaviour and dispersal ability, they do not have the same habitat requirements.…”