National Park Service

Northeast Temperate Network (NETN)

atmospheric deposition and stress

Background

Land cover — the surface components of land that are physically present and visible — provides a means to examine landscape patterns and characteristics. Patterns and landscape characteristics are important in understanding the extent, availability, and condition of lands; ecological system extent, structure, and condition; and the potential for dispersion and effects of chemicals and other pollutants in and on the environment. Land cover represents a starting point from which a variety of monitoring activities can be performed. EPA considers land cover information to be critically important for a number of reasons, including the ability to assess nonpoint sources of pollution, to understand landscape variables for ecological analyses, to assess the behavior of chemicals, and to analyze the effects of air pollution.

Land cover, in its naturally occurring condition, integrates and reflects a given site’s climate, geology and soils, and available biota over a time span of decades or longer. Land cover can be affected on shorter time scales by naturally occurring disturbances (e.g., storms, floods, fires, volcanic eruptions, insects, landslides) and human activities. Land cover represents the results of both naturally occurring conditions and disturbances and human activities such as population change, industrial and urban development, deforestation or reforestation, water diversion, and road-building. Depending on one’s perspective, the changes wrought by natural processes and human activities can be perceived as improvements or degradations of the state of land cover.

Land Cover vs. Land Use

As scientists study land cover, they are also studying land use. Land use involves human activities that take place on the land such as farming, grazing, logging, and recreation. Land cover is often a reflection of land use. For example, if crops cover a section of land, land cover scientists can assume that the land’s use is agricultural. However, the correlation between land cover and land is not always so clear. If an area of land is covered with trees, the possible land use could be logging, recreation, conservation, or something else.

Importance & Issues

jefferson salamanderLand cover is important because it affects other environmental variables including water quality, watershed hydrology, habitat and species composition, climate, and carbon storage. Land cover influences the mass and energy exchanges between the surface and the atmosphere and thus influences weather and climate.5 Land cover is also a primary ingredient of ecological structure and function, with changes affecting species habitat and distribution. Land cover changes in watersheds can alter hydrologic regimes, runoff patterns, and flood buffering.

Land cover data provides key information on the status and extent of ecological systems; land use data for the larger park region provides important information on habitat alteration and a wide variety of stressors associated with land use change. Land cover change was identified as a high priority issue for all network parks due to concerns arising from the negative effects of habitat conversion within and adjacent to park boundaries. This is particularly true within NETN because many parks are relatively small and potentially affected by outside activities. At a watershed level, land use and land cover affect the quality of aquatic environments (Stauffer et al. 2000, Meador and Goldstein 2003). An initial inventory of land use and land cover will provide context for the observed ecological conditions. If changes occur to this baseline condition, they can be interpreted in the context of land use or land cover at the watershed scale. Aquatic ecosystems respond to changes in land use and this response has been documented in urban, agricultural, and forested environmental settings (Meador and Goldstein 2003). Land use and cover are important vital signs because they integrate across multiple spatial scales; from the buffer around an individual stand, to the larger ecosystem complex within a park's boundary, to the distribution of systems within the region. By implementing a basic land cover change monitoring program, inferences can be drawn between measurable changes in park ecological integrity and anticipated negative effects. Land cover change detection has been identified as a high priority vital sign by most other networks within the Inventory and Monitoring Program, especially those in the eastern United States where human populations have increase dramatically during the last century. The NETN is cooperating with researchers at the University of Rhode Island to analyze land use and land cover change within and surrounding NETN parks (including 10 sections of the Appalachian Trail) between the 1970 s and 2002. A draft report of this analysis will be completed in 2006. Once the core NETN protocols are in place, NETN will work to develop a protocol for evaluating landscape change every 5 to 10 years. We will use landscape change information to test whether trends in other monitoring data can be explained by changes in land use and land cover metrics.

Preliminary Monitoring Objectives

Monitoring objectives will be a part of the protocol development.

Potential Measures

Road network extent, nearby housing development permits, proportion of nearby lands in various categories of human uses, % impervious surface in watershed, nearby human population density, landscape buffers.


 

Last Updated: December 30, 2016 Contact Webmaster