Abstract

Although the flood pulse is recognized ask a key force responsible for the diversity and productivity of floodplain ecosystems, the mechanisms involved are poorly understood, particularly for dryland river systems. The general objective of the proposed research is to investigate the influence of flood pulses on the structure and functioning of dryland riparian ecosystems. Specifically, the research has two main objectives; 1) determine the influence of natural flood pulses on organic matter, nutrient, and microbial dynamics and 2) quantify the effects of disconnecting the riparian ecosystem from surface flooding upon selected structural and functional attributes. The proposed research will be conducted along the Mimbres, Upper Gila, and Middle Rio Grande in New Mexico. Dams, levees, and channel entrenchment along these systems have disconnected sections of riverine forest (bosque) from the flood pulse for periods up to 50 years. A detailed investigation of the response of connected forest fragments to natural floods will be conducted, along with a comparison of naturally flooded and disconnected forest. The proposed research will advance our understanding of the influence of hydrologic variability on the ecology of dryland river ecosystems, contributing to their management and restoration. The results will be directly relevant to the management and conservation of the Conservancy's priority sites along the Gila, Mimbres, and San Pedro rivers, as well as other dryland systems throughout the West and around the world.

Publications

Seely, M.K. P. Jacobson, J. Henderson, P. Heyns, T. Nakale, K. Nantanga, and K. Schachtschneider. Ephemeral and endoreic river systems: their relevance and management challenges. Proceedings of the Okavango Pilot Project, UNESCO, in press.

Jacobson, P., E. Westergaard, C. Crawford, C. Dahm and M. Molles. In Prep. Hydrologic alteration and the fate of a Rio Grande cottonwood forest in central New Mexico: a tree-ring tale.

Jacobson, P., K. Jacobson and M. Lundgren. In Prep. Hydroclimatic controls on decomposition in the Chihuahuan Desert.