Plants and animals in the York River and its watershedprovide many ecosystem services. Forests reduce sediment runoff and excess nutrients, and provide nesting sites for bald eagles, osprey, and herons. Underwater grass beds sustain the young of striped bass, blue crabs, and other aquatic species. Grass beds and tidal marshes also reduce shoreline erosion,particularly during storms. Plankton, tiny floating plants and animals, sustain the fish and shellfish that people like to eat. Development in the watershed, that removes natural buffers and allows sediment runoff, threatens to undermine the healthy workings of this intricate web.
The York River watershed contains more than 250 species of fish, 190 species of birds, 50 species of mammals, 36 species of reptiles, and 26 species of amphibians. In the warm months, the York River is home to sea turtles and marine mammals, including bottlenose dolphins, which are protected by federal law.