Poster Session: Human Influences on Landscape and Hydrological Processes

Legacies of prehistoric agriculture in modern Sonoran Desert plant communities. Schaafsma, Hoski^*,1, Briggs, John¹, ¹ Arizona State University, Tempe, AZ, USA

ABSTRACT- Anthropogenic disturbances often alter local patch-dynamics and successional processes. These patches may be difficult to determine in areas with species with longevities measured in hundreds and thousands of years as seen in some desert plants. Recent research has shown that prehistoric (∼750 years BP) farming has produced measurable legacies in present day Sonoran Desert plant communities. Our study area was a five-mile reach of Cave Creek in Central Arizona that encompassed the first terrace with a total area of 124 ha; prehistoric fields make up 9% of the area. The differences between the fields and the remainder of the first terrace show that almost 1/10th of the area has been modified by humans and retains legacies of these changes up to 800 years after abandonment. Legacy effects have been measured on the fields in the woody, cacti and herbaceous communities. Changing 9% of the landscape has consequences for the patch-dynamics of the system as a whole by altering plant communities as well as producing differences in habitat. These results show that archaeological research coupled with plant biology may provide a way to assess processes of disturbance, succession, patch creation and patch dynamics in plant communities with extreme longevity. The results also have serious implications regarding past human interaction with the landscape; the wide distribution of archaeological sites suggests that large areas of the Sonoran Desert have been a patchwork of anthropogenic disturbances and subsequent succession for at least the last two thousand years.

KEY WORDS: anthropogenic changes, legacy effects, archaology/landscape ecology, agriculture, patch dynamics