Community type and disturbance type interact to determine disturbance response: implications for extending the environmental filter metaphor

Ecological disturbances act as environmental filters by removing species with particular characteristics, resulting in community types associated with different disturbance histories. However, studies to date on community responses to disturbance have neglected the potential for different community assemblages to display different responses. Using lotic invertebrate communities as a study system, this study investigated the influence of community composition on disturbance response. We undertook a 26-h stream channel experiment to test how distinct invertebrate community types (an undisturbed spring community, flood-disturbed community, and agriculture-disturbed community), shaped by specific disturbance histories and characterised by different species with particular functional groups, responded to additional disturbance of varying types and combinations (an undisturbed control, high-flow, nutrients, sediment, and a combined sediment and nutrients treatment). Invertebrate drift was used as a diagnostic tool to assess community responses. Significant three-way interactions were identified for total invertebrate drift, drift of typically sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera) and drift of cased organisms between community type, disturbance type and time, indicating that disturbance history and corresponding community type influenced community response to disturbance. Differing responses to disturbance between community types were often characterised by specific taxa, likely driven by adaptive traits, but also by phenotypic plasticity and altered biotic interactions. Community responses to the multiple disturbance scenario suggested potential for interactive effects, with differing responses potentially driven by species co-tolerance mechanisms. When determining the impacts of disturbance, our results suggest there is insight to be gained from a broader perspective incorporating multiple community types into future research. This approach could also improve management outcomes, facilitating tailored restoration and conservation strategies.