Crop landscapes reduced taxonomic and functional richness but increased evenness of aquatic macroinvertebrates in subtropical rivers
GOMEZ, DANIELA; CARLOS MOLINERI
ENVIRONMENTAL MONITORING AND ASSESSMENT
Lugar: Berlin; Año: 2019
Human activities altering ecosystems structure and function worldwide strongly affect rivers. Westudied aquatic macroinvertebrate communities (taxonomic and functional diversity) from rivers immersedin a forest matrix and rivers flowing through croplands.As rivers of the region experience a monsoon climate,high and low water seasons were also considered andtheir effect tested. We expected lower taxonomic andfunctional diversity in rivers flowing through croplands,and also during high water periods. We selected fivePiedmont forest and three sugarcane crop rivers in Austral Yungas piedmont forests (Argentina), where marginal vegetation, land use, and hydromorphological variables were studied. Samplings were performed in these8 sites during high and low water seasons of threeconsecutive years, totaling 32 samples. We analyzeddifferences between categories through nonparametricanalyses of variance and SIMPER analysis. We studiedtaxonomic diversity through effective number of speciesand functional diversity using feeding groups with afactorial ANOVA. We calculated different biotic indicesto test differences in water quality. We identified 11,034specimens from 58 families of aquatic macroinvertebrates. Piedmont forest rivers showed higher richness(order 0) than crop rivers, but diversities of orders 1 and2 showed the opposite pattern. Functional feedinggroups were different between both situations. Seasongreatly influenced the assemblages, with reduced diversity and abundances during high water periods. Bioticindices showed good water quality, except during highwater season for crop sites. A complex response ofaquatic communities was found, but generally crop siteswere more markedly affected during high water season.