How do humans restructure the biodiversity of the Sonoran Desert?
Hope, D*,1, Gries, C1, Kaye, J1, Zhu, W2, Stuart, G1, Oleson, J1, Katti, M1, Warren and N Grimm, P1, 3, 1 Arizona State University, Tempe, AZ, USA2 SUNY-Binghamton, Binghamton, NY, USA3 Virginia Tech, Blacksburg, VA, USA
ABSTRACT- Humans exert a profound effect on the Sonoran desert ecosystem. An extensive integrated field inventory was conducted to study broad-scale patterns of biodiversity across the entire urbanized, suburbanized, agricultural and surrounding desert landscape of the Central Arizona-Phoenix region. We used a probability-based dual-density tessellation stratified design to survey diversity of perennial plants, pollen, birds and sample soil chemistry at 204 sites in 2000, supplemented with geographic and socioeconomic variables from existing databases and the US Census. Dominantly geomorphic controls on spatial variation in perennial plant diversity and soil nitrogen concentrations in undeveloped desert, were replaced by variables such as current and former land use, family income, population density and housing age across urbanized parts of the region. There was widespread deposition of imported exotic pollen taxa across the region, in addition to that from native desert species, with significant variation in abundances - even for taxa with very mobile wind-dispersed pollen. Bird species richness increased with plant species diversity, plant volume, number of new houses and family income (in summer). We conclude that urbanization has resulted in a landscape in which biodiversity reflects social, economic and cultural influences in addition to those recognized by traditional ecological theory.
Key words: biodiversity, urbanization, social variables
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