Ecosystems (USGS)

Ecosystems, according to the website, are "integrated systems of organisms interacting with their physical environments," and the USGS (U.S. Geological Survey) "conducts research and monitoring to develop and convey a fundamental understanding of ecosystem function and distributions."

Major sub-topics of particular interest regarding wildlife are:

Wildlife: Terrestrial and Endangered Resources Program
Fisheries: Aquatic and Endangered Resources Program
Genetics and Genomics
Invasive Species Program
Status and Trends Program