Responses of riffle beetle assemblages to deforestation in a semi-deciduous Atlantic Forest remnant.

Bruna M Braun,Tiago R.N Bertaso,Marcia R Spies,Carla B Kotzian,Mateus M Pires

doi:10.1590/0001-3765201820160853

Abstract

Deforestation affects freshwater assemblages since aquatic organisms are dependent on the structure of the riparian vegetation. To investigate the responses of riffle beetles (Elmidae) to deforestation, this study assessed the structure of riffle beetle assemblages found in streams running through a large and well-preserved semi-deciduous Atlantic Forest remnant in Southern Brazil and in nearby deforested areas. Additionally, the effects of different substrate types (litter and stone) on the assemblages were assessed. Riffle beetle assemblages showed a remarkably distinct structure between forested and deforested areas. Lower abundance occurred in deforested streams. Indicator genera of forested streams were detected (e.g.,Macrelmis and Microcylloepus), while a generalist genus (Heterelmis) predominated in deforested streams. Substrate type did not affect the composition of riffle beetle genera, although higher abundance was found in litter. Our results are likely associated with changes in the vegetation type and levels and quality of allochthonous material input between forested (native and higher levels) and deforested (exotic and lower levels) streams, which are directly linked to the feeding habits of riffle beetles. Thus, our study reveals an interesting potential of riffle beetles as indicators of stream ecological integrity in semi-deciduous areas of the Atlantic Forest biome.

Highlights

Forest ecological integrity plays an important role in the conservation of the stream fauna (Nessimian et al 2008)
The larval stage of Heterelmis Sharp, 1882 was dominant in both forested and deforested streams and in litter substrate, and its adult stage was predominant in deforested streams and in both substrate types
The structure of riffle beetle assemblages was sensitive to forest integrity in the Parque Estadual do Turvo (PET) conservation unit and to land use in nearby agricultural converted areas

Summary

Introduction

Forest ecological integrity plays an important role in the conservation of the stream fauna (Nessimian et al 2008). Alterations in riparian vegetation can directly influence macroinvertebrates, because they are dependent on the quality of organic matter entering the streams for their feeding habits (Márquez et al 2015, Graça et al 2015) Responses to such environmental alterations include changes in macroinvertebrate assemblage structure (composition and richness) (Lorion and Kennedy 2009, Corbi et al 2013). Changes in specific riparian vegetation features can affect macroinvertebrate assemblage structure Such features include riparian vegetation size, width (buffer effect), longitudinal position (upstream, downstream), composition (tropical, temperate deciduous) and distance from other forest fragments and converted areas (Roy et al 2003, Fend and Carter 2005, Death and Collier 2010, Reid et al 2010, Nessimian et al 2008, Lorion and Kennedy 2009, Corbi et al 2013, IñiguezArmijos et al 2014). Macroinvertebrate assemblage responses are not standardized (Fend and Carter 2005) since other environmental factors may interact with riparian vegetation features (e.g. regional geomorphology and superficial geology), and hinder the finding of clearer patterns (Shearer and Young 2011)

Methods

Results

Discussion

Conclusion