Distribution of benthic macroinvertebrates in a tropical reservoir cascade

Abstract

The functioning of systems arranged in cascades of reservoirs can be explained by the Cascading Reservoir Continuum Concept, providing a theoretical framework for addressing ecological processes. In this context, this study tested the following hypotheses: (i) the benthic macroinvertebrate assemblage shows a nested distribution along a reservoir cascade; and (ii) local factors explain the structure of the benthic assemblage in every reservoir along the cascade. Macroinvertebrates play essential role in aquatic systems, especially due to recycling and, in reservoirs, as important links in every food chain. Sampling was conducted quarterly between October 2006 and September 2010 in six reservoirs located in the São Francisco River, Brazil. The benthic macroinvertebrate assemblage showed nested distribution in the reservoirs, indicating that a loss of species occurs along the cascade. Each reservoir presented a different set of variables that explained the distribution of macroinvertebrates, showing the importance of local factors determining the composition and distribution of benthic assemblages in the reservoirs. Therefore, there is a clear interaction between the position of a reservoir along a cascade and the macroinvertebrate assemblages, which indicate the importance of considering this pattern during the decision-making process of constructing new dams on rivers already regulated.

Effects of dams decrease zooplankton functional β‐diversity in river‐associated lakes

“…The increasing number of dams in large rivers has changed the landscape, resulting in various effects on biodiversity, demanding new approaches to analyse these effects on ecosystem functioning and community structures (Santos et al., ). We observed that damming decreases zooplankton functional β‐diversity in river‐associated lakes.…”

Patterns of reproduction and growth of the catfishIheringichthys labrosus(Lütken, 1874) after a reservoir formation

“…In this context, new environmental conditions can act as environmental filters for the establishment of new species and the population dynamics of existing species, since the construction of dams can lead to the loss of biodiversity (Santos et al., ), and even the displacement of sensitive species to headwater regions (Oliveira et al., ). The ichthyofauna is recognized as one of the assemblies most impacted by habitat fragmentation caused by the construction of reservoirs (Agostinho et al., ; Barletta et al., ), mainly due to the sudden change of lotic to lentic environments.…”

“…there is no evolutionary history that allows these species to possess characteristics enabling them to live in artificial lakes. Thus, pre-adapted species will colonize and succeed in this new landscape and environment (Agostinho et al, 2016). To understand the population and colonization patterns of these species it is essential to provide knowledge on the basic population parameters, such as reproduction period, first maturation size, reproduction areas, growth rates, maximum length and mortality rate, which are often basic entry parameters in population and assessment models (Dei Tos et al, 2002;Zhang and Megrey, 2006;Maunder and Punt, 2013;Methot and Wetzel, 2013).…”

Small dams also change the benthic macroinvertebrates community in rocky rivers

“…These consequences can be observed in compartments along reservoirs and downstream it dams (Nogueira, 2000(Nogueira, , 2001Mitsuka & Henry, 2002). Among the several communities of aquatic ecosystems affected by a new lentic environment, the benthic macroinvertebrates show an important tool in recycling nutrients and in the change of energy and mass among trophic levels (Santos et al, 2015). The structure of insect community and other aquatic invertebrates can be modeled in relation to the natural and anthropic changes (Silveira, 2004).…”