<b>Does riparian vegetation affect fish assemblage? A longitudinal gradient analysis in three Amazonian streams

Abstract

The degradation of riparian vegetation in low-order streams can cause irreversible environmental damage, biodiversity loss and alter the structure of communities. In this context, the present study evaluated how the level of degradation of riparian vegetation influences the fish assemblage in three low-order streams in the Brazilian Amazon. In each stream, three different stretches were delimited, distributed in the environments of forest, edge and pasture, and the samplings were conducted in three hydrological regimes using dip nets. Influences of the stretches and streams on richness and abundance were tested with GLMM, on the composition with PERMANOVA and on indicator species with IndVal. Species richness was higher in forest environments and lower in pasture; while abundance was higher in pasture and lower in forest. Species composition differed between stretches, streams and in the interaction between stretches and streams, with a strong difference between stretches of forest and pasture environments. Six species dependent of the riparian vegetation were classified as indicators of forest environments; while a generalist species was indicator of pasture. These results reinforce the negative influence of riparian vegetation removal on biological communities and provide subsidies that can help in the conservation and management of these systems.

The influence of sand extraction on fish assemblages in campinarana streams in Cruzeiro do Sul – AC, Brazil

“…and Virgilio et al (2018). Although Carnegiella strigata was found in anthropized environments in the present study, we also found it as an indicator of the preserved areas due to the great abundance of individuals in these streams.…”

A ictiofauna de igarapés da microbacia do Belmont, um sistema hidrográfico degradado pela expansão urbana na Amazônia Sul Ocidental

“…Porém é comparável com os resultados de inventários em pequenos igarapés em outras microbacias amazônicas em condições semelhantes de redução da cobertura florestal ciliar. Entre esses: microbacias da Amazônia Central (23 espécies - Beltrão et al, 2018), Meridional (39 espécies -Santos et al, 2017, Ocidental (32 espécies - Virgílio et al, 2018) e Oriental (29 espécies - Ilha et al, 2019).…”

How modified landscapes filter rare species and modulate the regional pool of ecological traits?

“…Human-modified areas are characterized by lower richness and higher dominance than forested areas (Sykes et al, 2019). In addition to diversity loss, deforested areas usually exhibit differences in species composition (Brejão et al, 2018;Virgilio et al, 2018) associated with the homogenization of riparian vegetation, changes in microhabitat composition, and reduction of the water column due to increased sedimentation and silting (Ramalho et al, 2014;Montag et al, 2019). These changes are related to species-specific traits and have a marked effect on the functional structure of communities.…”