Methods: Long-term Observations of Small Mammal Population Dynamics

Sampling of small mammal populations will employ mark-recapture methodology in which animals are captured in Sherman livetraps, baited with sunflower seeds, and incorporating bedding material. Traps will be checked 3 times per day over a period of 4 days (Rexstad 1996).Estimates of density will be derived from hollow grids (Efford in press), with estimates derived using models of movement to estimate animal density.

Four replicate grids, each consisting of 38 traps, will be deployed in both the upland and floodplain habitats of BCEF, near LTER1 and LTER2 meteorological sites. Density estimates will be produced annually in August for each of these sites. Correlational analyses will be done to assess relationships between meteorological factors and microtine abundance.

In anticipation of the peak in snowshoe hare abundance, predicted to occur in 2008-2009, we will place small (20g) radiotransmitters upon adult hares in both upland and floodplain habitats. We predict greater predation upon small individuals in upland sites where red squirrels are more abundant (O’Donoghue 1994). These transmitters will allow us to track individuals daily, and assess their survival, and forces of mortality that operate upon them.

Efford, M. In press.< Density estimation in livetrapping studies. Submitted to Oikos.

O'DonoghueM. 1994. Early survival of juvenile snowshoe hares. Ecology 75:1582-1592.

Rexstad, E. 1996. Small mammal sampling protocol for long term ecological monitoring program, Denali National Park and Preserve. Submitted to National Park Service.