Incorporating costs, thresholds and spatial extents for selecting stream bioindicators in an ecotone between two Brazilian biodiversity hotspots

Biomonitoring is critical for characterizing and monitoring status, spatial patterns, long-term trends in the ecological condition of freshwater ecosystems. The selection cost-effective bioindicators a step establishing such programs. Key indicator considerations are reliable response to anthropogenic disturbances, high benefit-cost-ratio sensitivity at multiple extents. We evaluated non-linear responses Ephemeroptera, Plecoptera Trichoptera (EPT) fish effects native vegetation loss within buffers 100 m 1000 assessed sampling processing costs involved each assemblage. sampled 37 neotropical stream sites Formoso River network, karstic region Bodoquena Plateau, midwest Brazil, lying ecotone between Cerrado Atlantic Forest biological hotspots. used TITAN (threshold taxa analysis) identify six taxa, four EPT genera two species. had low negative thresholds loss, whereas species positive thresholds. Thresholds were lower than EPT. most sensitive taxon (Macronema, Trichoptera) threshold 0% nearly 40% buffers. For richness, we found no buffer extent nor total cost biomonitoring was US$ 3,616; fish, 1,901. Although less expensive EPT, they did not respond negatively their started 48%, level that highly disruptive Therefore, do recommend using monitor on headwater streams Plateau. 52% more assemblage monitoring, it detected earlier impacts biota, especially buffer. early warning indicators Plateau headwaters.