Comparison of structural and functional approaches to determining landuse effects on grassland stream invertebrate communities

摘要: Effective catchment management in the face of landuse alteration depends on our ability to quantify ecologically significant changes and discriminate among varying levels impact. We compared efficiency traditional structural indices change (species composition) with functional measures based species traits (including life-history, trophic, morphological features) an analysis grassland streams along a gradient agricultural development (ungrazed native tussock, grazed extensively pasture, intensive dairy deer farming). Streams were categorized relation overall intensity, separately terms increasing nutrient concentrations fine sediments streambed. Only 5 60 individual demonstrated separation across gradient, whereas 14 53 trait categories did so. Traits associated population resilience (short generation time, asexual reproduction) became more prevalent intense pressure, reflecting predicted increases intensity frequency stream disturbance. observed shift away from tendency lay unattached eggs at water surface stream, likelihood smothering by sediment, as well highly flexible streamlined body shapes. Principal components correspondence analyses involving or composition all able practises, but between-landuse variance was accounted for than composition. All biological correlated both sedimentation. Nutrient better related trait-category densities, sedimentation trait- category relative abundances. Overall, successfully complemented helping differentiate consequences intensification communities. Rather simply recording loss reduction species, approach identify sensitive life-history characteristics linked functioning ecosystems, thereby facilitating targeted actions.