EMBRACE-EAR-Seed: Quantifying the hydrologic impacts of plant invasions in a peri-urban forest

Forests in the United States are dramatically changing. Although forests serve as living water filters globally, invasive plant species in many forests drive biodiversity loss, degrade soils and impact water use. Invasive species spread because they often consume more water and have longer growing seasons than native species.

In heavily invaded forests, the fraction of rainwater that transitions to groundwater or becomes surface water also declines. Concurrently, white-tailed deer benefit invasive plants by grazing on native species and their population has never been higher. Given the significant extent of invasions in contemporary forests, these plants are likely to reduce the amount of precipitated water ultimately delivered to rivers and streams.

Given the ubiquity of severe plant invasions throughout American forests, these investigators will assess the effect of invasive plants on water budgets and how the hydrologic cycle respond to forest rehabilitation and remediation. The researchers will engage in understory restoration projects to eradicate invasive plants and replant native species with the goal to restoring water availability.

The findings will provide insights into the profound changes underway in eastern forests that, if not addressed, could result in substantial reductions of water available for human use.

The proposed research will investigate invasive plant species impact on forest water budget by rehabilitating a forest on Chatham University campus in Pittsburgh, Pennsylvania by removing invasive species, replanting native species, and constructing deer-exclusion fences, to keep out deer that feed on native species. Most of the ~400-acre campus is composed of secondary-growth forest with understories dominated by invasive species common throughout the northeastern United States.

The proposed research will design experiments to rehabilitate forest plots through invasive species removal, excluding deer using fences, and replanting native species. High-frequency weather data and soil moisture measurements will be collected in restored and control plots to create a water budget for the forest to assess and quantify the extent to which invasive plant species impact soil water.

The project will provide hands-on research experience for undergraduate students, integrate the students into hydrology, geoscience and STEM. The project will facilitate the establishment of a long-term ecohydrology observatory on the Chatham University Campus in Pennsylvania.

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.