Effects of hydrological, environmental and spatial factors on fish diversity and community structure in oxbow lakes from the Amazon floodplain

Effects of hydrological and spatial seasonality on taxonomic and functional diversity of fish assemblages in an Amazonian floodplain lake

“…Different to what was expected, alpha diversity did not present significant differences in all the strata subjected to taxonomic analysis, even in the high‐water phase and low‐water phase. The effects of the flood pulse are common in these environments and have a predominant influence on the variation of alpha taxonomic diversity (Silva et al., 2021; Virgilio et al., 2022). The Amazon region is recognised for having the greatest diversity and endemism of fish species in the world (Liermann et al., 2012), which are governed by the regimes of the water levels (Silva et al., 2021).…”

“…The Amazon region is recognised for having the greatest diversity and endemism of fish species in the world (Liermann et al., 2012), which are governed by the regimes of the water levels (Silva et al., 2021). In addition to significant differences not occurring between the high‐ and low‐water phase, the alpha taxonomic diversity showed a higher average for the Shannon and Pielou indices in the high‐water phase, but it is during this phase that there is a clear loss of alpha taxonomic diversity (Virgilio et al., 2022). The possible seasonal mischaracterisation in Lake Cujubim can be attributed to a series of intervening anthropogenic factors, especially the construction of dams along the Madeira River.…”

“…In floodplain lakes, local fish communities that are interconnected by the dispersal of multiple, potentially interactive species fall within the domain of metacommunity assumptions (Leibold et al., 2004). These communities have been studied in a number of hydrographic basins of the world, including the Amazon basin, where different processes are related to the structuring of the metacommunity of fish in the marginal lakes of the floodplain (Jin et al., 2019; Virgilio et al., 2022). Metacommunities delimited by patches of habitat are expected to occur within a floodplain lake, despite the dispersals caused by the flood pulse and its interactions with the main river (Hurd et al., 2016).…”

“…Taxonomy and functionality are conventionally taken into account when calculating diversity indices, as they are complementary ecological indicators for assessing fish assemblages in aquatic ecosystems (Wang et al., 2019; Zhang et al., 2021). Alpha and beta diversity indices can be estimated based on taxonomic and functional facets for fish metacommunities (Virgilio et al., 2022; Wang et al., 2019; Zhang et al., 2021). Although the use of functional diversity is more recent, it is noteworthy that the procedure of dividing species into groups based on functional characteristics provides an important perspective on how fish communities are shaped by environmental constraints resulting from flood pulses (Villéger et al., 2017).…”

Geomorphological habitat type drives variation in temporal species turnover but not temporal nestedness in Amazonian fish assemblages

“…These movements are associated with the exploitation of allochthonous food resources in lakes, channels, and inundation forests (Fernandes 1997, Henderson and Crampton 1997) or the availability of dissolved oxygen (Crampton 2011). Many floodplain fishes become concentrated into shallow lakes from which they disperse laterally as water levels rise (Henderson and Crampton 1997, Fernandes et al 2014, Röpke et al 2016, Virgilio et al 2022). The annual flood pulse also triggers upstream high‐water longitudinal reproductive migrations of large‐bodied river‐floodplain species, which serve to colonize new feeding grounds and compensate for passive downstream drift of larvae as they recruit into floodplains (Duponchelle et al 2021).…”