Relative importance of local and landscape variables on fish assemblages in streams of Brazilian savanna

Abstract

Understanding variability in the composition of aquatic assemblages requires a multiscale perspective, since processes operating at different spatial scales (from regional to local) drive the community assembly. Here, the relative importance of environmental variables on fish species composition in streams of the Brazilian savanna (Cerrado) is assessed and quantified at local and landscape scales. The importance of both local and landscape environmental variables in structuring fish assemblages was supported. Local variables explained a substantially higher amount of variance of fish assemblages than landscape variables. However, the shared explanation indicate that landscape variables had a complementary effect. The streams sampled were mostly headwaters at similar altitudes and with similar watershed sizes, so the sensitivity of the fish assemblages, even to small landscape gradients, is highlighted. Maintaining these important instream habitat characteristics close to natural conditions seems to be essential for conserving stream fish species, and for this, the landscape context should be taken into account. Considering the near‐pristine condition of the streams studied, these findings can be used as a reference for further studies addressing the effects of human modifications on stream fish biodiversity of the Cerrado.

Landscape factors modulating patterns of salmonid distribution during summer in north Patagonian rivers

“…Fish–environment relationships are expected to derive both from common ancestry (promoting the dominance of a species but inhibiting the occurrence of others) as well as evolutionary convergence in response to a common set of environmental filters in the region. Although influence on fish communities by landscape‐scale features has been reported previously (Barbosa et al ., 2018, Marchetti et al ., 2004, Stanfield et al ., 2006), this is the first report of such dynamics in North Patagonia. We discuss the implication of fish abundance and distribution patterns, the way assemblages are structured and potential drivers of O. mykiss trout dominance in the region.…”

“…In our study, sampled streams are mostly headwaters encompassing a narrow range of the landscape gradient. This limited range could be the reason why landscape variables explained comparatively less variation than reported elsewhere (Barbosa et al ., 2018, Stanfield et al ., 2006). Nonetheless, our findings suggest that some landscape traits are important enough to produce responses in fish assemblages along a landscape scale environmental gradient.…”

Stream fish metacommunity organisation across a Neotropical ecoregion: The role of environment, anthropogenic impact and dispersal-based processes

“…substrate composition, hydrological features, and cover) [27,28,29,30], topographic variables (e.g. latitude, slope) [31,30] and even current and past climate conditions [1,32,33,34]. Large scale studies have established the importance of climatic variables by demonstrating that these variables can be good predictors of the occurrence of organisms [eg.…”

Métodos Quantitativos Para Mensurar a Diversidade Taxonômica Em Peixes De Riacho

“…Por exemplo, a declividade da bacia tem forte influência sobre a velocidade da correnteza (Benone et al 2017) e a conversão de áreas naturais em pastagens alteram a vegetação ripária (Casatti et al 2015). Essas métricas de ampla escala também afetam os peixes de riacho, que são sensíveis a mudanças na altitude (Costa et al 2018), declividade (Barbosa et al 2019, Benone et al 2020a) e das alterações humanas (Casatti et al 2015, Terra et al 2016, Benone et al 2020b.…”