- [Amphibian] |
- [Aquatic Macroinvertebrates] |
- [Bald Eagles] |
- [Freshwater Mollusks] |
- [Long-term Monitoring Plots] |
- [Mule Deer] |
- [Sage Sparrow Habitat] |
- [Small Mammals] |
- [Salmon] |
- [Steelhead] |
Small Mammals, Reptiles, and Invertebrates
Section 10.11.3.3)K. D. Hand,
J. A. Stegen, and
R. E. Durham
Three Biological Resources Management Plan plots (Figure
10.11.8; plots 6, 10, and 19) located on the Hanford
Central Plateau were surveyed in May 2005 to estimate
small mammal, invertebrate, and lizard species richness
and to document the presence/absence of species that are
federally or state protected and/or sensitive. Plots 6 and 10
were selected for monitoring based on their location on the
200 Area plateau and because these plots were burned in
the 24 Command Wildland Fire in June 2000. Plot 19 is
located northwest of the 200-West Area and was not burned
in the 2000 fire. The plots within the fire footprint are
currently classed as bunchgrass mosaic vegetation cover and
have sparse patches of young shrubs scattered through the
plots. Vegetation found on monitoring plot 19 is a big sagebrush
– spiny hopsage/bunchgrass mosaic.
Live-trapping was used to sample the small mammals, reptiles, and invertebrates on the plots. One hundred and forty-seven Sherman live traps and 36 pitfall traps were placed on each plot and sampled over a 4-night period. The Sherman traps were used to capture small mammals, while pitfall traps captured lizards and invertebrates.
Four small mammal species were captured on all three plots: the northern grasshopper mouse (Onychomys leucogaster), white-footed deer mouse (Peromyscus maniculatus), Great Basin pocket mouse (Perognathus parvus), and Townsend’s ground squirrel (Spermophilus townsendii). Mammalian species richness was greatest at plot 6 with four species, plot 10 had the next greatest with three, and plot 19 had the lowest species richness with two species found (Table 10.11.4). Reptilian species richness was also greatest at plot 6 (four species), followed by plot 10 (two species) then plot 19 (zero species) (Table 10.11.5). However, the two snakes captured are considered incidental because the trapping methods were not considered suitable for capturing snakes. The invertebrate species’ richness (Table 10.11.6) did not follow the trend seen for small mammals and reptiles, plot 19 had the greatest number of species with 26, followed by plot 10 with 18 species, and plot 6 with 17 species.
The relative abundance and species richness of small mammals
in 2005 were compared to similar data collected on
these monitoring plots in 1998 before the 2000 24 Command
Wildland Fire. In all three plots, the relative abundance
of small mammals was higher in 2005 after the fire
than in 1998 (Figures 10.11.10 through 10.11.12). Species
richness was also higher on the two burned plots (plots 6 and
10) in 2005 compared to 1998. Two additional species were
found in 2005 on the burned plots compared to no change on
the unburned plot. Changes in species abundance and composition
may be related to differences in the amount of
ground litter and the vegetative community after a fire
(http://www.npwrc.usgs.gov/resource/habitat/fire/smmammal.htm).
Two Washington State Species of Concern candidate species and one monitor species were encountered during this effort. The Townsend’s ground squirrel, a state candidate species as of July 1, 2005, was present on plot 6. The sagebrush lizard, a state candidate species as of July 1, 2005, was present on plot 6. The northern grasshopper mouse, a state monitor species as of July 1, 2005, was present on plots 6 and 10.
