Habitat Alteration: Research

Aquatic Stressors

Vegetated Aquatic Habitats

Vegetated aquatic habitats are environments such as freshwater or estuarine wetlands, marshes, and seagrass beds. These environments are special because they are some of the most widespread and productive types of aquatic habitat. Many recreationally and commercially important fish, shellfish, and wildlife, as well as rare and endangered species, depend on vegetated aquatic habitats as sources of food, shelter, and nurseries. Aquatic vegetation also strongly influences substrate type and stability, wave and current energy, and water quality-all key factors that determine the suitability of a given environment to serve as a habitat for a given species.

Models

The first step in understanding how populations respond to changes in their habitat is to chose specific species for study and to determine the ways these species are dependant upon a given habitat. Based on this understanding, scientists can assess the ways a population responds to alterations of its habitat. This data can subsequently be used to develop computer-based numerical models designed to quantitatively predict the effects of habitat alteration on a multitude of organisms and to extrapolate information from a well-studied area to another less well-studied area or to extend predictions to a larger spatial or temporal scale.

Native Fish

Observed declines in the number of salmon and other native fish in the Pacific Northwest and in the Great Lakes have spurred EPA scientists to research the factors responsible. This research includes examining how the management of upland within the watershed affects lacustrine and riverine habitats and takes into account the fact that fish migrate between water bodies at different times and at different stages of life.

Wildlife

EPA scientists are interested in developing and improving ways to assess the risks to wildlife populations that are posed by chemical and non-chemical stressors across large regions. An on-going case study and demonstration project is that of the common loon and its responses to mercury contamination and habitat alteration. Research activities within the loon project include the development of geospatial modeling methods to assess the relative effects of heterogeneously distributed stressors, including dietary methylmercury, habitat degradation, acidification, and human disturbance. Also under development are methods to identify spatial relationships among stressors, potential interactions among stressors, and the relative risks among potential stressors to populations of loons at varying spatial scales.

Habitat Alteration: Research

Aquatic Stressors

Vegetated Aquatic Habitats

Models

Native Fish

Wildlife

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