Plumas - Lassen Administrative Study Small Mammal Module
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Plumas-Lassen Administrative Study Small Mammal Module Project Leader Robin J. Innes1 Graduate Student Jaya R. Smith1 Principal Investigators Douglas A. Kelt1, Dirk H. VanVuren1, and Michael L. Johnson2 1University of California Davis Department of Wildlife, Fish, and Conservation Biology 2University of California Davis John Muir Institute of the Environment Module Objectives Evaluate management effects on small mammals Trends in abundance Develop and test predictive models Habitat associations and spatial organization Outline Module objectives Methods and results Long-term grids Landscape transects Biology of focal species Dusky-footed woodrat Northern flying squirrel Outline Module objectives Methods and results Long-term grids Landscape transects Focal species biology Dusky-footed woodrat Northern flying squirrel Methods: Long-term Grids Trapping array 100 Sherman traps, 10-m spacing 72 Tomahawk traps, 30-m spacing 2.25 ha 4 nights Sampled biannually Methods: Long-term Grids Pre- and Post Treatment Canopy Cover 100 Pretreatment Post treatment 80 Canopy Cover (%) 21 grids in 5 habitat types 60 40 20 12 placed in experimental plots 0 Control Light thin Heavy thin Group select Treatment Type Mixed-conifer Mixed-fir White fir Pine-cedar Red fir 3 control 3 light thin 3 heavy thin 3 group select Results: Long-term Grids 2007 marked 5th year of data collection, 1st year of post-treatment data In 2007, captured 732 individuals of 10 species Deer mice and chipmunks most common Results: Trends in Deer Mouse Abundance T re n d s in D e e r M o u s e A b u n d a n c e in F iv e F o re s t T yp e s Deer Mouse Peromyscus maniculatus Mean Deer Mouse Abundance (N) 50 M ix e d -c o n ife r M ix e d -fir P in e -c e d a r R e d fir W h ite fir 40 30 20 10 0 2003 2004 2005 2006 2007 Year Brush Mouse Peromyscus boylii Forest type & year explained 93% of variation Microhabitat & year explained 69% of variation Results: Trends in Deer Mouse Abundance do s uins eDAe be ur nMdoaun sc e A nd e s t T yp e s T re n d s in DTe reernM inbFuiv e aFnocre Deer Mouse Peromyscus maniculatus 5500 M ix e d -c o n ife r M ix e d -fir P in e -c e d a r R e d fir W h ite fir Mean Mouse Abundance(N) (N) DeerDeer Mouse Abundance D eer M ouse 4400 3300 2200 1100 00 22000033 2 20 0 0 44 2 02 0050 5 2 020060 6 2 020070 7 era r YY ea Brush Mouse Peromyscus boylii Forest type & year explained 93% of variation Microhabitat & year explained 69% of variation Results: Fall Conifer Cone Production Trends in Cone Production 80 Conifer Cone Abundance 60 40 20 0 2003 2004 2005 Year 2006 2007 Results: Fall Conifer Cone Production Trends in Deer Mouse Abundance Relative to Cone Production 80 Conifer Cone Abundance Deer Mouse Abundance 60 40 20 0 2003 2004 2005 Year 2006 2007 Results: Annual Snow Fall Trends in Total Snow Fall 80 Total Snow Fall 60 40 20 0 2003 2004 2005 Year 2006 2007 Results: Annual Snow Fall Trends in Deer Mouse Abundance Relative to Snow Fall 80 Deer Mouse Abundance Total Snow Fall 60 40 20 0 2003 2004 2005 Year 2006 2007 Results: Trends in Deer Mouse Abundance Trends: Forest type Microhabitat Year Deer Mouse Peromyscus maniculatus Winter severity Fall cone production Trends in Northern Flying Squirrel Abundance Mean Flying Squirrel Abundance (N) 1.4 Results: Trends in Abundance Flying Squirrel 1.2 1.0 0.8 0.6 0.4 0.2 0.0 2003 2004 2005 2006 2007 Year Trends in Dusky-footed W oodrat Abundance T re n d s in D e e r M o u se A b u n d a n ce 30 0.8 D e e r M o u se Deer Mouse Abundance (N) W oodrats Mean Abundance (N) 0.6 0.4 0.2 0.0 25 20 15 10 5 0 2003 2004 2005 Year 2006 2007 2003 2004 2005 Ye a r 2006 2007 Results: Impacts of Treatments on Deer Mouse Abundance Pre- and Post Treatment Deer Mouse Abundance Mean Deer Mouse Abundance (N) 25 20 Group select Heavy thin Light thin 15 10 5 0 Pre Post Treatment (time) Results: Impacts of Treatments on Deer Mouse Abundance Pre- and Post Treatment Deer Mouse Abundance Mean Deer Mouse Abundance (N) 25 20 Group select Heavy thin Light thin Control 15 10 5 0 Pre Post Treatment (time) Results: Impacts of Treatments on Deer Mouse Abundance Pre- and Post Treatment Deer Mouse Abundance Mean Deer Mouse Abundance (N) 25 20 Group select Heavy thin Light thin Control 15 10 5 0 Pre Post Treatment (time) Need to continue monitoring efforts for 2-5+ yrs post-treatment to effectively measure treatment effects Outline Module objectives Methods and results Long-term grids Landscape transects Focal species biology Dusky-footed woodrat Northern flying squirrel Methods: Landscape Transects TU-3 1 2 3 4 5 Methods: Landscape Transects Placed in various forest types throughout Plumas National Forest Trap design 4 points, 3 traps at each point 50-m spacing, 0.25 ha 2 sessions, 4 nights Results: Landscape Transects 2007 marked 2nd and final year of data collection Captured 2,513 individuals of 14 species at 367 census points across 4 treatment units Outline Module objectives Methods and results Long-term grids Landscape transects Focal species biology Dusky-footed woodrat Northern flying squirrel Focal Species: Dusky-footed woodrats Neotoma fuscipes Natural History Semi-arboreal, nocturnal rodent Oak specialist Build “houses” Used for: Food storage, nurseries, & protection Built: Ground, cavities &limbs of trees Objectives To determine habitat associations Forest type Relationship with California black oak Microhabitat Tree and ground house site selection and use To determine spatial organization Home range Overlap Results: Habitat Associations of Woodrats ↑ oak density = ↑ woodrat density Ground house sites: ↑ large logs, ↑ large stumps, and ↑ slope Tree house sites: large oaks, large snags House use: ↑ use of tree houses in the fall Results: Woodrat Home Range Home range size was 1.2-3.8 ha (3.0-9.4 acres) Lack of overlap indicates territoriality Relative to other populations: ↑ home ranges, ↓ woodrat density Forage availability? Suggests home ranges likely to be ↑ in winter when resources are scarce
