Human Impact on the Mesquite Woodlands

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Did you know that every person hiking along a recreational trail in a forest setting has a potential impact on wildlife? Not all wildlife reacts the same way to human disturbance. In fact, some species are so highly sensitive that any human activity along a trail can affect their territory selection, their reproductive success and the time and energy they need to go about their daily business of survival Large-scale native woodland loss in the Lower Rio Grande Valley of Texas during the 20th century has been reported in the literature. Cameron County corroborate previous estimates of native woodlands loss in the Lower Rio Grande Valley, though at a slightly lower percentage (91%). Comparisons with recent land-use and land-cover mapping show that much of the loss was a result of agricultural expansion. Results about changes in land cover for the study period indicate that extensive, highly connected grassland and desertscrub areas are the most vulnerable ecosystems to fragmentation and actual loss due to encroachment of xerophytic mesquite woodland. In the study period, grasslands and desertscrub not only decreased in extent but also became more fragmented. That is, the number of grassland and desertscrub patches increased and their average patch sizes decreased. In stark contrast, the mesquite woodland patches increased in size, number, and connectivity. These changes have important impact for the hydrology of the region, since the energy and water balance characteristics for these cover types are significantly different. The process demonstrates a simple procedure to document changes and determine ecosystem vulnerabilities through the use of change detection and indicator development, especially in regard to traditional degradation processes that have occurred throughout the western rangelands involving changes of vegetative cover and acceleration of water and wind erosion. Vegetation change in the American West has been a subject of concern throughout the...
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