condition represents a threat to the coastal marine ecosystem 
and fisheries in this region of the Gulf. Landscape Ecology 
methods provide a tool to assess the impact of human landuse 
practices that are being implemented to improve environmental 
quality. 
In years past, the freshwater marshes, stream bank 
areas, and bottomland swamps of the Tensas River Basin were 
under strong development pressures. Large portions of forest 
near streams and in backwater swamp areas were converted to 
agriculture. This loss of forested areas decreased filtering 
capacity that normally removes pollution and nutrients before 
they enter streams, lakes, and estuaries. Wetland forests also 
dissipate energy and nutrients associated with extreme 
precipitation events and therefore reduce damage to down¬ 
stream farms and cities resulting from floods. The Tensas River 
Basin is unique in that natural levees along the riparian vegeta¬ 
tion lie on the highest ground in the Basin. This causes 
drainage water to run parallel to streams for many miles before 
actually entering the stream and river water channels. Wet¬ 
lands and backswamps then become the vegetation filtering 
areas for pollutants and nutrients. Preserving or restoring 
wetland forests have other economic benefits including wetland- 
based recreation, including hunting and harvesting wetland 
plants. The people who live within the Tensas River Basin 
realize that the vegetation along a stream and in backswamp 
areas can influence the condition of both the stream bank and 
the water in the stream. Restoration efforts began in the early 
1990s. 
The strip of vegetation along streams is known as 
the riparian vegetation zone. It is commonly described by the 
types of vegetation it contains and by the presence of water. 
In an ideal situation, many pollutants and fertilizers will be 
intercepted or absorbed by the riparian vegetation and it’s root 
system. This helps to keep the streams clean. Bank erosion 
is also mitigated by intact riparian vegetation. The conditions 
of the riparian ecosystem over a whole watershed can be 
studied in order to learn where, for example, a restoration 
project would most improve water quality. Similarly, a charac¬ 
terization of riparian conditions over the entire Tensas River 
Basin can help to identify which areas of the Basin are most 
likely to see improved water quality as a result of riparian 
vegetation improvements. 
Land cover is the product of past land uses on the 
backdrop of the biophysical setting. A map of landcover is 
essentially a picture of the dominant vegetative, water, or 
urban cover in an area. The images of land cover in the 
Tensas River Basin for 1972 and 1991 (see above) are based 
primarily on images taken by the Landsat Multispectral 
Scanner satellite since the early 1970s. The land cover map 
was based on the North American Landscape Character¬ 
ization (NALC) data, a Federal effort to create similar data for 
the entire oountry. The resolution of the land cover data is 60 
meters, so each pixel (picture element) represents an area 
about the size of a football field. Although individual 
pixels are far too small to be rendered accurately here, 
the visual impression of broadscale regional patterns is 
readily apparent. Forest vegetation shows up on the 
image as red in color, agriculture shows up as light red, 
grey, light blue and white and almost always shows a 
pattern with rows or right angles typical of farm fields. 
These images were then classified for landuse. 
The classifications were forest, human use (urban and 
agriculture) and water. Through the use of computerized 
Landscape analyses, the 1972 image was compared to 
the 1991 image and changes in forest areas and human 
use areas were calculated. As the images show, there 
was a tremendous forest loss over that time period. In 
1972 the land cover types forest and agriculture covered 
an area of about 34% and 65% of the area, respectively. 
In 1991 the land cover types forest and agriculture 
covered an area of about 22% and 77% of the area, 
respectively. Where forests have been removed, agricul¬ 
ture and urban land covers become more dominant, this 
can be seen by comparing the images to observe the 
forest loss over 20 years. 
The images also show how the forest, agricul¬ 
ture and urban landcover vary across the landscape of the 
Tensas River Basin. Understanding the variation of 
landcover with respect to landscape features, such as 
cities, roads, lakes and streams, is the foundation of the 
landscape ecological assessment. Other landscape 
indicators include: population density and change, human 
use index, roads, roads along streams, percentage of 
forest cover, forest fragmentation, percent of the water¬ 
shed in the largest forest patch, forest analysis of the 
Tensas River Basin, vegetation change, vegetation 
change by subwatershed, forest and crop land along 
streams, watershed indicators, riparian analysis, 
vegetation change along the Tensas River Reach, 
backswamp area analysis, soil erodibility analysis, and 
wetland restoration analysis. 
The Tensas River Basin is one of 2,099 individual 
watersheds located across the United States. Many 
people throughout the United States are restoring riparian 
vegetation areas and are in need of GIS and landscape 
methods to help them make good decisions on the best 
locations for restoration sites. 
