An Ecological Assessment of the Louisiana Tensas River Basin Chapter 3 
Humans in the Landscape 
Human Use Index 
Humans structure the landscape for their purposes, and 
landscapes structure human activities. For example, 
humans may decide the shapes and sizes of individual 
agricultural fields, but watershed-scale patterns of topog¬ 
raphy, soils, and geology determine whether or not there 
can be fields at all. Because human-dominated land¬ 
scapes are used for different purposes which impose 
different patterns, land use history is always important for 
understanding local landscapes. The interplay between 
humans and landscapes has created a tapestry of multi¬ 
scale patterns in the Tensas River Basin, and combina¬ 
tions of these two factors influence the sustainability of 
ecological processes. 
Population Density and Change 
The proportion of an area that is used for agriculture or 
urban land use is a measure of human use known as the 
U-index. We often assume that humans tend to simplify 
their environment. At landscape scales, however, the map 
of human land use displays complicated patterns (Figure 
3.4, Land Cover). The scale at the transition from simple 
to complicated patterns might be a measure of the scale to 
which humans have structured a landscape or, conversely, 
the scale at which geophysical processes constrain 
human activity. By looking at watershed patterns of the U- 
index, it is possible to identify those areas which have 
experienced the greatest land cover conversion from the 
natural cover of vegetation. 
According to the U.S. Census Bureau, the population of 
the Tensas River Basin in 1990 was about 29,300 
people, which represents about 0.0001 of the total 
population of the United States. With a population of 
29,300 covering an area of 3,763 square kilometers, the 
average population density of the Tensas Basin is about 
7.8 people per square kilometer. 
Between 1970 and 1990, the total population in the 
Tensas Basin (East Carroll, Madison, and Tensas par¬ 
ishes) decreased from 37,680 to 29,300. Thus, the 
average population density decreased from about 10 
people per square kilometer to 7.8 people per square 
kilometer. Figure 3.5 shows the population of the 
Tensas River Basin by parishes and the populations of 
three cities in the Basin. 
Figure 3.5 
Population (1990) of Louisiana Parishes within the 
Tensas River Basin. 
