Data from: Beta diversity of aquatic invertebrates increases along an altitudinal gradient in a Neotropical mountain

Mountains harbor rich biodiversity and high levels of endemism,
particularly due to changes in environmental conditions over short spatial
distances, which affects species distribution and composition. Studies on
mountain ecosystems are increasingly needed, as mountains are highly
threatened despite providing ecosystem services, such as water supply for
half of the human population. We aimed to understand the patterns and
drivers of alpha and beta diversities of aquatic invertebrates in
headwater streams along an altitudinal gradient in the second largest
South American mountain range, the Espinhaço mountains. Headwater streams
were selected at each 100 m of elevation along an altitudinal gradient
ranging from 800 to 1400 m asl, where three substrate types per stream
were sampled: leaf litter, gravel, and cobbles. Environmental variables
were sampled to represent local riparian canopy cover, instream physical
habitat, water quality, climatic data, and land use. Generalized linear
models and mixed models were used to test relationships between altitude
and the richness and abundance of invertebrates and to assess the
influence of environmental variables on the same metrics. Patterns of
spatial variation in aquatic invertebrate assemblages along the
altitudinal gradient were assessed using multiplicative beta diversity
partitioning. The richness and abundance of aquatic invertebrates
decreased with increasing altitude, whereas beta diversity increased with
increasing altitude. Significant differences in assemblage composition and
in relative abundance of invertebrates were observed for both substrates
and altitude. We thus show that the high regional beta-diversity in
aquatic ecosystems in the studied site are due to the high turnover among
areas.