Skip to main content
Dryad

Data from: Macroinvertebrate community responses to disturbance in a fragmented river with contrasting legacies of alteration

Data files

Aug 26, 2024 version files 266.32 KB

Abstract

Flow is a critical factor determining riverine ecosystem structure and function. Widespread hydrologic alteration, however, has impacted the ecological integrity of rivers in ways that are not well understood, including responses of biological communities to increasingly frequent and severe climatic disturbances. Our study compared responses of invertebrate communities on woody debris to large flooding and extreme drought in two highly contrasting segments of an impaired low-gradient river. The upstream segment, which according to previous research has higher α-diversity and production of large-bodied and sensitive invertebrates, maintained higher flows and longitudinal connectivity throughout the four-year study. Communities in this upper segment resembled one another among sites (lower spatial turnover), but experienced greater temporal shifts in composition associated with hydrological disturbances. Conversely, invertebrate communities in the highly altered downstream segment, which is impaired by reduced flow, sedimentation, and hypoxia, were comprised of smaller-bodied and pollution-tolerant taxa with lower α-diversity. Unlike the upper segment, communities were patchily distributed among sites (higher spatial turnover), which made it more difficult to detect system-wide temporal variation in composition throughout the study. Our study underscores the benefit of including measures of connectivity and spatial heterogeneity when assessing the ecological integrity of lotic systems. Understanding system-wide response to disturbances across longer time frames can help better predict and mitigate the impacts of climate change on ecosystem integrity in degraded rivers.