PARENT SESSION
Oral Session #48: Vegetation Change and Response.
Presiding: D. Zobel
Tuesday, August 6. 1:00 PM to 4:45 PM. Mesquite Room, Radisson.
Land-use legacies of cultivation in the semi-arid west: a case study in Owens Valley, California.
Elmore, Andrew*,1, Hamburg, Steven1, Manning, Sara2, Mustard, John1, 1 Brown University, Providence, RI2 Inyo County Water Department, Bishop, CA
ABSTRACT- Understanding how the land use history of a region affects modern vegetation patterns could be key to predicting the ecological response to environmental stress, natural or anthropogenic. However, the effect of past land-use practices is largely unstudied in semiarid ecosystems, and therefore confounds our attempts to sustainably manage these lands for grazing and water extraction. At the peak of agricultural activities in the 1920s in Owens Valley, California (comprising 1000 km2) cultivated land covered 20% of the valley floor, yet today it is largely absent. Using detailed historical maps of cultivation patterns in combination with 1987 vegetation surveys and satellite measurements of land cover change over the past 15 years we have examined an 80-year land-use legacy. Our results show distinct compositional differences between cultivated and uncultivated lands. In addition, during periods of drought plant cover on cultivated land fluctuated more than cover on uncultivated land. The patterns of vegetation change were also strongly influenced by depth to water table. The shrub Chrysothamnus nauseosus is more commonly found on previously cultivated land while Sarcobatus vermiculatus and Atriplex confertifolia are associated with uncultivated land. These results indicate that seral plant communities on previously cultivated lands in a semi-arid ecosystem have a different composition and respond to natural climatic variability differently than do communities on uncultivated lands, strongly suggesting that effective management of these systems requires a recognition of their land-use history.
KEY WORDS: Land-use legacy, semi-arid, vegetation response, Chrysothamnus nauseosus