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Texas Tech University (2016)

Vegetation textures of dunes in arid and semi-arid regions

Johnson, Sarah E

Titre : Vegetation textures of dunes in arid and semi-arid regions

Auteur : Johnson, Sarah E

Université de soutenance : Texas Tech University

Grade : Master of Science 2016

Patches of vegetation within dune fields affect the amount of erosion that occurs. Ryu and Sherman (2014) analyzed coastal dune field vegetation cover with respect to climatic variables. This study follows the methodology of Ryu and Sherman (2014) and explores if similar results are found in arid and semi-arid dune fields by determining how different climate variables, such as wind duration and intensity, precipitation, and temperature correlate with the vegetation cover. This project requires thirty years of wind, temperature and precipitation data, as well as NAIP aerial imagery. Vegetation is mapped for seventeen study sites then these layers are analyzed with the program Fragstats, to determine the metrics of the field patterns. The various metrics are then analyized with a hierarchical cluster diagram to determine which variables describe the distribution of vegetation the best and then these metrics are statistically correlated with the climatic data using linear and multiple regression analyses. This study shows that arid and semi-arid dunes require different metrics to describe the fields than foredunes. As for climate variables, both studies have different classifiers. Ryu and Sherman (2014) found four climate variables best at distinguishing the different vegetation textures in foredunes : precipitation, the coefficient of variance of precipitation, potential evapotranspiration, and Lancaster’s (1988) mobility index. Arid and semi-arid dunes fields, however are predominantly described just with the amount of yearly precipitation.


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