Table 1.
Trapping Grid Characteristics and Woodrat Captures and Lodges by Study site in Vallecito, Calaveras County, California.
| Sitea | WRsb | Lodgesc | Understoryd | Canopyd | Maintenancee | Structuresf | Trapping grid description |
|---|---|---|---|---|---|---|---|
| 1 | 12 (3) | 10 (3) | 47.0 (50) | 55.8 (55) | None | No | Densely vegetated with the exception of a 20-meter wide grassy swath completely void of understory and canopy where no WRs were trapped |
| 2 | 5 | 2 | 24.2 (22) | 77.5 (90) | Moderate | Yes | Grassy open fields interspersed among oak and pine trees on an eastward facing slope; ornamental hedge by rock wall |
| 3 | 16 (5) | 18 (4) | 51.4 (55) | 77.1 (95) | None | No | Undeveloped land leased for cattle grazing; large-girth oak trees with expansive secondary branching of trunk base; dense berry vine patches; abundant downed wood (i.e., downed trees and smaller woody debris); grassy areas free from shrubbery, likely from cattle impact, scattered among oak trees |
| 4g | 7 (1) | 1 (1) | 21.7 (15) | 77.6 (92) | High | Yes | Fruit trees adjacent to trapping grid; ornamental, mat-forming nonnative groundcover (Vinca spp.) where no WRs were trapped |
aAcross all sites, dominant native tree species: interior-live oak (Quercus wislizenii), blue oak (Q. douglasii), and gray pine (Pinus sabiniana). Common understory species: toyon (Heteromeles arbutifolia), redberry (Rhamnus crocea), manzanita (Arctostaphylos spp.), poison oak (Toxicodendron diversilobum), chamise (Adenostoma fasciculatum), and buckbrush (Ceanothus cuneatus).
bNumber of woodrats captured per trapping grid (number of WRs captured at targeted dens on property but off the trapping grid).
cNumber of woodrat lodges detected within the trapping grid (additional lodges outside of the grid at which traps were placed).
dMean (median) percent understory and canopy cover based on trapping station measurements.
eModerate = periodic control of poison oak and some clearing of downed brush; High = carefully tended with complete clearing of brush piles and trimming of lower branches of oak trees.
fSite 2: workshed, abandoned chicken coop, and a small rock wall near the owner’s home; Site 4: well pump station, drainage pipe culvert, small guest house.
gSeveral WR carcasses were found on the north edge of the trapping grid during the August trapping session, and it was discovered that a neighbor was using rodenticide in a shed close to the property fence line.