Salt marsh harvest mouse abundance and site use in a managed marsh

The salt marsh harvest mouse (Reithrodontomys raviventris) is a federal and California listed endangered mammal endemic to the San Francisco Bay. The objectives of this research were to determine habitat use of endangered salt marsh harvest mice in a managed marsh in Fremont California, and to evaluate whether managed flooding of the marsh provides favorable habitat conditions for the mice. In addition, this research explores the effectiveness of using mark-recapture model selection analysis to estimate capture probability, survival, and population growth rate for salt marsh harvest mice. Mice were captured for four nights per month between May and August, 2008. Thirty-six unique salt marsh harvest mice were captured for a catch per 100 nights of trap effort of 1.9. The sex ratio of male to female mice was skewed towards males with a sex of 2.3:1. Salt marsh harvest mice were distributed randomly throughout the marsh and no relationships were found between mice distribution and pickleweed salinity, pickleweed height, distance to levees, distance to dry or filled water bodies, percent cover of vegetation, or sympatric rodents. The findings of this study indicate that catch-per-trap-effort, the current standard method to estimate salt marsh harvest mice populations, may not be accurate. The results of this study can be used by managers of salt marsh harvest mice habitat to manage and estimate mouse populations

Research on Chesapeake Bay and contiguous waters of the Chesapeake Bight of the Virginian Sea at the Virginia Institute of Marine Science, Gloucester Point, Virginia and Wachapreague, Virginia 1973-74 edition.

RANN (IRRPOS) project report ; no. 4

Extractable nitrogen and microbial community structure respond to grassland restoration regardless of historical context and soil composition.

Grasslands have a long history of invasion by exotic annuals, which may alter microbial communities and nutrient cycling through changes in litter quality and biomass turnover rates. We compared plant community composition, soil chemical and microbial community composition, potential soil respiration and nitrogen (N) turnover rates between invaded and restored plots in inland and coastal grasslands. Restoration increased microbial biomass and fungal : bacterial (F : B) ratios, but sampling season had a greater influence on the F : B ratio than did restoration. Microbial community composition assessed by phospholipid fatty acid was altered by restoration, but also varied by season and by site. Total soil carbon (C) and N and potential soil respiration did not differ between treatments, but N mineralization decreased while extractable nitrate and nitrification and N immobilization rate increased in restored compared with unrestored sites. The differences in soil chemistry and microbial community composition between unrestored and restored sites indicate that these soils are responsive, and therefore not resistant to feedbacks caused by changes in vegetation type. The resilience, or recovery, of these soils is difficult to assess in the absence of uninvaded control grasslands. However, the rapid changes in microbial and N cycling characteristics following removal of invasives in both grassland sites suggest that the soils are resilient to invasion. The lack of change in total C and N pools may provide a buffer that promotes resilience of labile pools and microbial community structure

Water quality and water-use conflicts in Lake Taabo (Ivory Coast)

The Lake Taabo (Ivory Coast, Africa) results of the construction of the Taabo dam on the Ban- dama River. The changes in the water level of the 69-km² lake depend on 1) the rainfall linked to alternating dry/wet seasons; 2) the extraction of water for human uses; 3) the discharge of water from the upstream dam and the volumes tur- bined by the Kossou dam; 4) the various an- thropic effects (discharge of untreated waste water from towns and industries, and leaching from agricultural land). The average concentra- tions of nutrients (NH4-N: 1.1 mg/L, NO3-N: 1.62 mg/L, PO4-P: 10 mg/L, SiO2: 15 mg/L) and chlo- rophyll a (from 4.8 to 16.5 μg/L, average 11.4 μg/L) indicates some degree of eutrophication. The cumulated effects that threaten the ecosys- tem (degradation of water quality and eutrophi- cation) are such that they are likely to interfere with various water uses. In a context of growing health and environmental concerns in Africa, this study demonstrates conflicts between dif- ferent uses of this water resource and the urgent need for an appropriate policy including specific monitoring of lake water quality, wastewater control, and a programme to reduce agricultural fertilizers

Biogeochemical processes in sagebrush steppe: Interactions of terrain, vegetation and chemical cycles

Publications, manuscripts in various stages of progress, presentations made at scientific meetings, and undergraduate honor thesis and one Ph.D. dissertation are contained