Macroinvertebrate data collected in streams of the Tapezco river catchment, Alajuela, Costa Rica

This data set and the corresponding document provides information about macroinvertebrates collected in different streams located in the Tapezco river catchment (Alajuela, Costa Rica). This region is intensively used for horticultural farming of vegetables and, therefore, pesticides are heavily applied posing risks to aquatic biota after entering the streams. The objective of this information is to describe the status of water pollution, and assess its negative effects on macroinvertebrate communities with the application of two indexes, the Costa Rican Biological Monitoring Working Party (for organic pollution) and the Species at Risk Index (for pesticide pollution). Both approaches led to comparable results indicating that most of the investigated sites, showed altered macroinvertebrate communities, related to water pollution.