3 years ago

Disentangling spatial and environmental determinants of fish species richness and assemblage structure in Neotropical rainforest streams

Sébastien Brosse, Kévin Cilleros, Régis Vigouroux, Luc Allard
Freshwater ecology templates were developed in temperate streams, but whether they also apply to tropical streams that harbour a higher biological diversity than their temperate counterparts remains uncertain. This is particularly true for tropical fish assemblages inhabiting small streams that have been less studied than larger, higher-order lowland streams. Here, we disentangled the strength of spatial (longitudinal and environmental) drivers, and scale-specific (drainage basin, reach and local scale) determinants of species richness and composition of freshwater fish assemblages inhabiting small streams in French Guiana. We found that species richness increased from upstream to downstream but also with increasing local habitat structural diversity independently of stream position in the upstream–downstream gradient. This pattern was shared by the two most speciose fish orders (Characiformes and Siluriformes), demonstrating that species addition rather than species replacement shaped species richness in these assemblages. Species composition of fish assemblages was determined equally by their spatial structure within drainage and by the environment, and assemblages differed both with distance and along an upstream–downstream gradient. The environmental effect on species assemblages indicated by the fact that almost all environmental descriptors had slight but nonetheless significant effects on assemblage composition, probably reflecting species-specific responses to the local environment. In contrast, despite a strong micro-endemism between drainages for some taxa, assemblages were only slightly affected by river drainage identity, since widespread species were a common constituent of assemblages in all rivers. We identified five species assemblages characterising different local habitat features from torrential areas to lowland muddy areas. We also distinguished fish assemblages from confluence areas with larger rivers, which differed from the other five assemblages. The fish zonation patterns we report can constitute a benchmark for future studies measuring the impact of anthropogenic disturbances on Neotropical forest streams.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1111/fwb.12981

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.