Landscape ecology is an interdisciplinary science framework that studies the relationship between spatial patterns of landscape characteristics and conditions of and risks to ecological resources, including forests, rangelands, wetlands, rivers, streams, lakes, and urban environmental settings. Local, regional, national, and global economies depend upon both goods and services resulting from ecological resources. Forests provide materials for many different types of paper products; agricultural systems provide food for the world population; coastal waters provide an abundant food resource; wetlands, streams, and rivers provide numerous recreational opportunities. Moreover, these resources provide services that sustain ecological goods, jobs, and human well-being. Forests help reduce flooding risks by intercepting rain and causing water to trickle down to the earths surface, as well as slowing the speed of surface flow. As a result of gentle impact with the earths surface, forested areas are less likely to loose soil. Wetlands and forested areas along streams and rivers (the riparian zone) help reduce the loss of soil off of agricultural areas and reduce the loading of excess nutrients (for example, nitrogen and phosphorus) to streams and rivers; this helps sustain a healthy fish population.
Historically, environmental programs have focused on managing relatively local scale problems. And although it is important to manage the amount of pollution coming from factories, sewage treatment plants, and other facilities, many of our environmental problems of today result from cumulative impacts of humans across large areas. We now recognize that declines in the fishing industry in coastal areas result from excess pollutants and nutrients coming off of extensive agricultural areas. Similarly, declines in salmon populations in the Pacific Northwest have resulted from a combination of alternation of river flows and forest harvest practices. Declines in breeding bird populations have been associated with the loss and fragmentation of large blocks of interior forest and natural vegetation types. An increase in the frequency and magnitude of floods that cause extensive property damage and the loss of human life has been associated with increases of impervious surfaces in extensive agricultural and urban areas. These changes affect all aspects of human well-being including the ability to sustain jobs, and to protect human lives and property. A number of new projects have been initiated that will address broad-scale environmental conditions, including a national environmental report card being completed under the guidance of the Committee on the Environment and Natural Resources, a committee that reports to the Vice President of the United States. Moreover, regional groups comprised of agencies and private individuals and corporations have been formed to address broad-scale environmental conditions. These groups include areas such as the Great Lakes, the Gulf of Mexico , and the Chesapeake Bay Basin.
Both the amount and spatial pattern of ecological resources and human activities affect our ability to sustain desired environments. Agricultural activities on marginal lands, such as farming on steep slopes with highly erodible soils, increase soil loss and loadings of sediment and nutrients to streams. Loss of trees in and around urban areas increases impervious surfaces and the frequency and magnitude of flooding that threaten human life and property. Cumulative loss of forests along streams, where people tend to develop lands, increases soil loss, flooding risk, and the loadings of sediment and nutrients to streams. In order to understand risks to ecological resources and humans, it is important to analyze the spatial pattern of environmental conditions on scales ranging from local communities to entire regions.
Until recently, it was not possible to study the spatial pattern of ecological resources and human environments at a variety of scales. However, advances in computer technology and development of new databases, now make it possible to analyze spatial pattern at scales ranging from communities to the entire globe. For example, the EPA in combination with other Federal agencies, recently completed a land cover database MRLC of the lower 48 United States. These data are based on satellite imagery and go down in scale to 30 meters, approximately the area of the infield on a baseball field, and are consistent in terms of their classification, nationally. This consistency allows us to compare spatial patterns of ecological resources in many areas of the United States. Through the use of geographic information systems (GIS) software, it is possible to calculate metrics of landscape composition and pattern. With todays computer and GIS technology, it is possible to analyze the spatial pattern of ecological resources across the entire United States in a matter of days. However, without an understanding of how pattern affects the conditions of and risks to ecological resources, calculation and interpretation of landscape metrics are of limited value.
Landscape ecology provides the theoretical framework for analyzing spatial patterns relative to ecological condition and risk. However, studies relating pattern to ecological conditions are limited, and these studies generally cover limited geographic areas. Therefore, one of the important goals of the Landscape Ecology Program is to quantify the relationships between landscape pattern (measured as spatial metrics), including human activities, and ecological resources at community, watershed, regional, and continental scales. This basically means turning landscape metrics into landscape indicators indicators of ecological condition and risk. Because these relationships are likely to vary in different regions of the United States, the Landscape Ecology Program has initiated projects in different regions of the United States.
The Landscape Ecology Program was founded as part of the Environmental Monitoring and Assessment Program in 1992. The primary goals of the program were similar to those of the program today (1) to develop landscape pattern indicators of human activities and the environment that relate to observed conditions in ecological resources, including forests, wetlands, streams, lakes, estuaries, arid lands, and (2) to assess landscape pattern across broad areas through the use of comprehensive spatial databases. In 1994, the program published its first national research strategy . In 1995, EPA’s research program was reorganized. As a result, two new exposure research programs were formed; the Landscape Ecology and the Landscape Characterization. In 1997, the Landscape Ecology program published its first regional-scale landscape assessment, "An Ecological Assessment of the United States Mid-Atlantic Region: A Landscape Atlas." The report has received extensive praise and methods and formats used in the report have been used by the State of Maryland in its State of the Environment reports. Additionally, EPA has used the report to prioritize environmental protection goals within the mid-Atlantic Region of the United States. Starting in 1996 and continuing to present, the Landscape Ecology Program extended its approaches to watershed-level initiatives. This includes projects such as the New York City Watershed Project, the San Pedro River Project, and the Tensas River Project. Since 1994, the Landscape Ecology Program has published several technical reports that have advanced the field of Landscape Ecology and environmental protection in specific areas of the United States. The most recent report, a research strategy to assess landscape change and affects to aquatic resources , was the Office of Research and Developments first technical publication of the year 2000. The strategy lays out a 10-year research strategy to assess landscape change from the early 1970s to the early 2000s, and how the change over that period of time affected the conditions of aquatic resources. The primary research and development goals in this plan are to:
- acquire and enhance spatial databases needed to conduct landscape
assessments at multiple scales across large regions
- develop new remote sensing techniques to detect landscape conditions
- develop techniques to evaluate landscape change across multiple sensors
- quantify relationships between landscape metrics that measure the
composition and spatial pattern of ecological resources and human activities
and observed conditions of and risks to ecological resources and their
- develop multi-metric statistical approaches (models) to assess the condition of and risks to ecological resources and their associated processes.
Additionally, the Landscape Ecology Program supports a relatively new initiative within EPA, the Regional Vulnerability and Assessment Program or ReVA. The primary aim of the ReVA program is to produce tools and methods to assess the vulnerability of ecological resources to current and future environmental stresses. Several key aspects of the Landscape Ecology Programs research, but especially spatial data acquisition and model development, are essential to the ReVA program. Therefore, the Landscape Ecology Program is focused on several critical scientific questions posed by ReVA.
Finally, the Landscape Ecology Program has produced numerous data sets of use to clients and the public, including a wide range of landscape indicator databases and user-friendly data browsers.
The following are some general approaches followed by the Landscape Ecology Program:
- conduct research (pilot) studies and assessments in areas that are:
- high priority to clients that will benefit from landscape level
- have sufficient environmental variable to assess specific research
and development questions
- have extensive landscape and field data
- possess a relatively different set of biophysical conditions (e.g.,
different climate zone)
- high priority to clients that will benefit from landscape level assessments
- conduct gradient studies to establish quantitative relationships between
landscape metrics and conditions of and risks to ecological resources
- answer as many critical research questions in existing pilot areas
- incorporate EPA Regional staff in the research project in order to
facilitate technology transfer
- collaborate with other agencies with interest/needs in landscape approaches
- use existing data, where possible, to address research questions
- follow up and work with clients to make sure that research and development
products meet their needs
The Landscape Ecology Program produces a number of products for a wide range of clients. The following are general categories of products produced for clients:
- Landscape assessment tools (ATtILA and AGWA)
- National assessments
- Regional landscape assessments
- Watershed-scale, landscape assessments
- Journal articles highlighting research findings
- Watershed-scale, landscape assessments
- Landscape metric databases
- Specialized applications of the landscape approach (e.g., Environmental Justice)