2010 Annual Report 1a.Objectives (from AD-416) a) Assimilation of remote sensing information into hydrologic modeling; b) Interpretation of remote sensing products in the context of ecohydrologic feedbacks. 1b.Approach (from AD-416) The experimental design is built on remote sensing, measurements and modeling to better understand the ecohydrologic impacts of climate change and woody plant encroachment. Experiments are planned for ARS watershed locations in Arizona, Oklahoma and Georgia. Documents SCA with U of AZ. Formerly 5342-12660-004-01S 58-5342-4-447. 3.Progress Report Invasive grasses altered the water cycle in semiarid rangeland. This study investigated a transition from a grassland dominated by native species to a non-native Lehmann lovegrass monoculture at a semiarid grassland site in southeastern Arizona. Results showed that the post-storm daily water loss due to soil evaporation (E) [relative to the daily evapotranspiration from plants and soil (ET)] was greater in post-transition years than in pre-transition years. Results indicated that, compared to a native assemblage, Lehmann lovegrass dominance may be associated with an increase in E/ET after precipitation in the summer growing season. Over the season, this resulted in a doubling of total seasonal E/ET after the Lehmann lovegrass invasion. These results should lead to a comprehensive understanding of the impacts of species invasion in semiarid grasslands. NP 211 Problem Area #5 Watershed Management, Water Availability, and Ecosystem Restoration. ADODR Monitoring Activities: The project was managed through close interaction (most UA students on the project are housed at the ARS laboratory) and in person meetings every two to three weeks between the primary UA faculty member, ARS scientists, and graduate students.