Environment and Spatial Influences on Aquatic Insect Communities in Cerrado Streams: the Relative Importance of Conductivity, Altitude, and Conservation Areas

Abstract

The aquatic insect community is an important element for stream functionality and diversity, but the effects of altitude and conservation areas on the aquatic insect community have been poorly explored in neotropical ecozone. The lack of studies about the relative importance of space and environment on community structure is another obstacle within aquatic insect ecology, which precludes the inclusion of these studies in more current frameworks, like the metacommunity dynamics. We evaluated the relationship between the aquatic insect community structure at 19 streams in the Brazilian Cerrado and spatial and environmental variables, namely geographical distance among sites, stream altitude, chemical variables, and environmental protection areas. We partitioned the variance explained by spatial and environmental components using a partial redundancy analysis. The environment exhibited a strong spatial structure for abundance and number of genera, increasing these community parameters with elevated water conductivity. Only community composition had a large unexplained portion of variance, with a small portion constrained by environmental (altitude and conductivity) and spatial factors. A relevant point in the result was the streams with high conductivity were located outside of the conservation areas. These results suggest that the relationship between number of genera and abundance with environmental conditions is always associated with spatial configuration of streams. Our study shows that altitude is an important determinant of community structure, as it exerts indirect influences, and electrical conductivity directly determines community composition, and that some national parks may be inefficient in maintaining the diversity of aquatic insects in the Cerrado region.

Effects of Environmental Changes on Gerromorpha (Heteroptera: Hemiptera) Communities from Amazonian Streams

“…Cunha and Juen [21] found an association between more generalist species such as Rhagovelia brunae with high values of conductivity, whereas more sensitive species such as R. jubata and R. evidis exhibited lower abundances in areas with lower conductivity. Similar to what we found in this study, Godoy et al [68] also found a greater explanation of water conductivity for the abundance of Heteroptera in Cerrado streams. There are indications that conductivity is one of the main components of the water in gradients altered by multiple land uses [69], which may also change the water's surface tension [58].…”

Association between Labeobarbus spp. (Teleostei: Cyprinidae) and environmental variables in the Luhoho basin (Eastern Congo River basin; DRC)

“…Marlier (1960) mentioned that in river systems of the Kivu region, several aquatic invertebrates are seemingly influenced by chemical characteristics of the water. In Brazilian rivers, electrical conductivity was found important to determine the macroinvertebrate community (Godoy et al ., 2017). Possibly, the differential distribution of the prey items explains the differences in the distribution of the two Labeobarbus species.…”

When phylogeny and ecology meet: Modeling the occurrence of Trichoptera with environmental and phylogenetic data

“…We highlight that the study only considered part of the niche structure of the genera (i.e., water pH). However, despite this variable being relevant for the community structure in Cerrado streams (Godoy et al., 2017), we need caution in exploring the results. Most genera occurred in streams with alkaline water.…”

“…However, despite this variable being relevant for the community structure in Cerrado streams (Godoy et al, 2017), we need caution in exploring the results. Most genera occurred in streams with alkaline water.…”