Interconnectedness during high water maintains similarity in fish assemblages of island floodplain lakes in the Amazonian Basin

Abstract

ABSTRACT. We conducted a study to test the hypothesis that interconnectedness among island floodplain lakes and the adjacent Solimões River during the flood stage of the hydrologic cycle is enough to maintain similarity in fish species assemblages. Gill net samples were collected during high and low water periods for three consecutive years (July 2004 to July 2006) in four lakes on Paciência Island. Two lakes, Piranha and Ressaca, are connected to the river all year, and the other two, Preto and Cacau, which are in the center of the island, are isolated during low water periods. The abundance, species richness and evenness of the fish assemblages in these lakes did not differ according to their relative positions or the season of the hydrological cycle, which confirmed our hypothesis. However, fish abundance during the dry season was greater than in the flood season. Apparently, the short period of full connection between the lakes is enough to allow the colonization of all fish species, but not to cause similar abundances. Our study indicates that persistence of the species composition of island floodplain lakes is primarily due to the annual replenishment of fish to the lakes during the flood season.

Effects of historic flooding on fishes and aquatic habitats in a Missouri River delta

“…However, structural indices of some fish communities may not be affected by floods, as in the upper Amazon River (Freitas et al 2010). The effects of floods are mediated by the magnitude, frequency, duration, timing, and rate of change of water levels (Richter et al 1996).…”

“…Our first objective was to assess how the flood impacted fish species richness, evenness, and diversity. We hypothesized that the flood would increase evenness and diversity without affecting richness (Freitas et al 2010;Gomes et al 2012;Steffensen et al 2014). Our second objective was to evaluate how the flood affected relative abundance of fishes as categorized by age class (i.e., juvenile, adult), morphology (i.e., smallbodied, large-bodied), introduction history (i.e., introduced, native), and recreational importance (i.e., sport fish, non-recreational species).…”

Floodplain fish communities in river systems in Bolivia: Current knowledge and addressing future research challenges

“…In general, it has been accepted that spatial habitat diversity promotes species diversity in fish communities. However, the seasonal habitat changes are less understood (Ayala et al 2000, 2003, Freitas et al 2010. There is evidence that important structural variations in fish communities occur among hydrological phases (Espírito-Santo et al 2013).…”

“…In these studies, body size has been shown to be a key parameter in trophic behaviour (Pouilly et al 2004b). Current knowledge on the spatial and temporal changes in floodplain fish communities and habitats can be complemented with studies on individual species with different morphological characters and life history-strategies (Freitas et al 2010, Castello et al 2011, Carvajal-Vallejos et al 2014.…”

Fishes from the Jaru Biological Reserve, Machado River drainage, Madeira River basin, Rondônia State, northern Brazil

“…The Neotropical realm (South and Central America) encompasses more than 4,000 valid fish species (Reis 2013), with the Amazon River basin harboring the world's greatest diversity of freshwater fish (Freitas et al 2010, Winemiller et al 2016, Reis et al 2016). To date, most studies of the Amazonian ichthyofaunal diversity have concentrated in the floodplains adjacent to large rivers (cf.…”