Collaborative Research: RAPID: Does a Range Shifting Species Alter Ecosystem Function?

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Organisms that feed on plants play important roles in moving energy and nutrients though ecosystems, which underlies many services that ecosystems provide to societies such as fisheries, clean drinking water, and carbon storage. However, the identity and abundance of organisms in ecosystems is changing as warm-climate species move into previously cooler regions that are disproportionately impacted by climate change. Understanding how these species movements alter ecosystem processes is an important step in anticipating and managing the impacts of climate change on ecosystems and their services. This research investigates how the establishment and subsequent population boom of a novel aquatic insect species into high elevation wetlands influences the timing and magnitude of processes central to all ecosystems, namely the consumption of plant material, the cycling of nutrients that support plant and animal growth, the availability of prey for predators, and the connections between freshwater habitats and the surrounding terrestrial environment. In addition to scientific advancement, this research advances early childhood education via childrens’ science camps, provides opportunities for public outreach during science tours at a field station, and trains the next generation of scientists by engaging undergraduate students from historically underrepresented groups in field-based ecological research.This research tests the novel hypothesis that the dominance of a range-shifting species with life history characteristics that differ from resident species will shift the phenology and magnitude of ecosystem processes, altering food-web energy transfer, and resulting in ecosystem state-shifts. Specifically, this research investigates the ecosystem impact of a large increase in the abundance of a recent range-shifting caddisfly (Nemotaulius hostilis) with novel life history trait of larval development occurring in the fall and winter, rather than summer like resident species. The research combines field measurements of organism biomass with assays of nutrient cycling and detritus processing to 1) quantify range-shifting and resident caddisfly population size and energy transfer to salamander predator populations; 2) experimentally test density-dependent competition for detritus resources between range-shifting and resident caddisflies; 3) leverage established models and a 30-year dataset on caddisfly and salamander abundance to estimate the past, contemporary, and future ecosystem-process-outcomes associated with range-shifting and resident caddisflies including detritus decomposition, nutrient release, and subsidies to the terrestrial ecosystem. This combined approach investigating interlinked ecosystem compartments generates a strong mechanistic understanding with general application. Moreover, by integrating the keystone top-predator into the research, we will develop new understanding of how top-down control influences the ecosystem outcomes of range shifts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.