Abstract:
Despite the importance of tropical montane cloud forest streams, studies investigating aquatic communities
in these regions are rare and knowledge on the driving factors of community structure is missing. The objectives
of this study therefore were to understand how land-use infl uences habitat structure and macroinvertebrate
communities in cloud forest streams of southern Ecuador. We evaluated these relationships in headwater streams
with variable land cover, using multivariate statistics to identify relationships between key habitat variables and
assemblage structure, and to resolve differences in composition among sites. Results show that shading intensity,
substrate type and pH were the environmental parameters most closely related to variation in community composition
observed among sites. In addition, macroinvertebrate density and partly diversity was lower in forested sites,
possibly because the pH in forested streams lowered to almost 5 during spates. Standard bioindicator metrics were
unable to detect the changes in assemblage structure between disturbed and forested streams. In general, our results
indicate that tropical montane headwater streams are complex and heterogeneous ecosystems with low invertebrate
densities. We also found that some amount of disturbance, i.e. patchy deforestation, can lead at least initially to an
increase in macroinvertebrate taxa richness of these streams.
