Ad Ecological Assessment of the Louisiana Tensas River Basin Chapter 2 
Human Use Patterns 
One of the simplest and most informative indicators of 
environmental impact is the extent to which humans 
have changed the natural vegetation to crops or urban 
land cover. These indicators are easy to interpret be¬ 
cause profound land cover changes influence almost 
every aspect of the environment from wildlife habitat to 
soil erosion. 
The national maps of human use intensity (Figure 2.4) 
show watershed rankings for both total human use- 
agriculture plus urban (Figure 2.4a) and only agriculture 
(Figure 2.4b). Urban areas are relatively minor in terms of 
total area, and farming areas are more extensive, so the 
two maps are very similar. Most of the human appropria¬ 
tion of land has occurred in the central United States and 
along the eastern seaboard. Higher elevations and the dry 
southwest appear to have been less impacted by conver¬ 
sion to agricultural or urban land cover. Like most of the 
south, Louisiana has a complicated pattern of land use that 
deserves more detailed attention. 
The chart gives some details about the distribution of 
human use intensity among watersheds. You can see that 
about 40% (800) of the watersheds have had only minor 
Agriculture or Urban Land Cover 
1000 . 
■o-d 800. 
|l 600 ' 
E jg 400. 
z| 200. 
10 2030405060708090 100 
Indicator V&lue 
Figure 2.4 
Proportion of watershed area with: (a) agriculture or urban land cover, (b) 
agriculture land cover. 
