Twenty-Third Annual Meeting and Symposium of the
Desert Tortoise Council, April 3-5, 1998
Abstracts

Recent linkages of ecological investigations to geosciences research on landscape dynamics and soils have proven essential for interpreting many ecological phenomena that occur on the extensive alluvial piedmonts or "bajadas" of the southwestern deserts. These piedmont environments are typically complex mosaics of alluvial deposits varying in geological age and parent materials. Soil-forming processes including accumulation and vertical redistribution of clay minerals and calcium carbonate in distinct soil horizons lead to increasing soil profile development over time. The degree of soil development has a profound impact on soil water balance. Soil characteristics that modify infiltration of water at the surface and recharge of subsoil horizons exert a major control on plant physiological responses and ultimately composition of vegetation. Varying soil hydrological dynamics also affect animal populations directly through limitations different kinds of soils impose on burrowing activities and indirectly by controlling the production of both herbage and seeds used by herbivorous and granivorous animals. Linking ecological studies of the desert tortoise with detailed knowledge of geological landscapes and soils could contribute to a better understanding of factors that limit this desert reptile.

References

McAuliffe, J. R. 1994. Landscape evolution, soil formation, and ecological patterns and processes in Sonoran Desert bajadas. Ecological Monographs 64:111-148.

McAuliffe, J. R., and E. V. McDonald. 1995. A piedmont landscape in the eastern Mojave Desert: examples of linkages between biotic and physical components. San Bernardino County Museum Association Quarterly 42:53 63.