Longitudinal dimensions of land-use impacts in riverine ecosystems

Dimensões longitudinais do impacto do uso do solo em ecossistemas de rios

Abstract:

Aim

Rivers are linked longitudinally via the flow of water and the spatial dimensions of the changes in local riparian vegetation are still poorly understood. Recent modifications to the Native Vegetation Protection Law allow reduction of lateral buffer strips and amnesty for riparian vegetation removal, which might increase the fragmentation of native riparian vegetation, especially for Atlantic Rainforest streams.

Methods

We present two case studies conducted in a stream draining a fragmented landscape in the Atlantic Rainforest. The stream flows through two abrupt transitions (forest-pasture-forest) and we investigated how far the upstream effects of a given riparian condition could be detected in the downstream reach for a suite of variables.

Results

We show that the effects of land cover propagate downstream for both algal and macroinvertebrate communities. For some variables of interest, these effects might extend up to a km downstream from the transition.

Conclusions

There is a need to understand how the distribution of riparian forest remnants contribute to maintaining watershed-scale resilience to impacts.

Keywords:
Atlantic Rainforest streams; habitat fragmentation; watersheds; land cover; longitudinal effect