The spatial component of variation in small-mammal abundance measured at three scales

2001 ◽  
Vol 79 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Jeff Bowman ◽  
Graham J Forbes ◽  
Tim G Dilworth
Keyword(s):  
Population Structure ◽  
Small Mammal ◽  
Spatial Scales ◽  
Deer Mouse ◽  
Abundant Species ◽  
Blarina Brevicauda ◽  
Spatial Population ◽  
Metapopulation Structure ◽  
Napaeozapus Insignis ◽  
Nested Grids

We studied small-mammal populations across a range of spatial scales to determine if they exhibited spatial variability that was independent of the distribution of vegetation. Between 1996 and 1999, systematic livetrapping surveys were conducted on nested grids at three scales: (1) extent (total area covered by a grid) = 4900 ha, grain (minimum space between sampling points) = 1000 m; (2) extent = 306 ha, grain = 250 m; and (3) extent = 31 ha, grain = 125 m. The four most abundant species were the red-backed vole (Clethrionomys gapperi), the short-tailed shrew (Blarina brevicauda), the deer mouse (Peromyscus maniculatus), and the woodland jumping mouse (Napaeozapus insignis). Small mammals exhibited spatial population structure over distances up to 250 m but not over 1000 m. There was a component of this population structure that appeared to be temporally and spatially dynamic, and that was not correlated with measured vegetation variables. We discuss processes that would create the observed metapopulation structure in seasonal landscapes.

scholarly journals Small Mammal Abundance and Diversity in Forests With and Without Canada Yew, Taxus canadensis

2003 ◽  
Vol 117 (3) ◽  
pp. 389 ◽  
Author(s):  
Jerrold L. Belant ◽  
Steve K. Windels
Keyword(s):  
Species Diversity ◽  
Small Mammal ◽  
Deer Mouse ◽  
Capture Rate ◽  
Upper Peninsula ◽  
Blarina Brevicauda ◽  
Northern Hardwood ◽  
Taxus Canadensis ◽  
Abundance And Diversity ◽  
Canada Yew

Canada Yew (Taxus canadensis) has been extirpated from much of its former range in northeastern North America possibly due to logging, fire, agriculture, and browsing by White-tailed Deer (Odocoileus virginianus). We compared the relative abundance and species diversity of small mammals in five northern hardwood stands containing Canada Yew to five adjacent stands without Canada Yew in the Upper Peninsula of Michigan, during October-November 2000. Overall, 72 individuals were captured (53 in yew, 19 in non-yew); dominant species were Short-tailed Shrew (Blarina brevicauda), Deer Mouse (Peromyscus maniculatus), and Red-backed Vole (Clethrionomys gapperi). Overall mean (+ sd) capture rate (individuals/100 adjusted trap nights) in sites with yew (5.5 + 2.2) was greater (P = 0.04) than mean capture rate in sites without yew (1.9 + 1.0). Three indices of species diversity suggested greater small mammal diversity in stands with Canada Yew understories in northern hardwood forests.

Small mammal and habitat response to shoreline cottage development in central Ontario

1982 ◽  
Vol 60 (5) ◽  
pp. 865-880 ◽  
Author(s):  
G. D. Racey ◽  
D. L. Euler
Keyword(s):  
Small Mammal ◽  
Deer Mouse ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Blarina Brevicauda ◽  
Tamias Striatus ◽  
Composition And Structure ◽  
Sorex Cinereus ◽  
Cottage Development ◽  
Mammal Diversity

Changes in small mammal abundance and habitat caused by shoreline cottage development in central Ontario were studied in the summers of 1978 and 1979. This development significantly altered the vegetation composition and structure in the vicinity of cottages. These alterations, in turn, had an impact on small mammal abundance. These animals were classified in three response categories: tolerant (existing, at some level, regardless of degree of development), intolerant (extirpated at high levels of development), and indifferent to development. Tolerant species were the eastern chipmunk (Tamias striatus), short-tailed shrew (Blarina brevicauda), and deer mouse (Peromyscus maniculatus); intolerant species were the masked shrew (Sorex cinereus), red-backed vole (Clethrionomys gapperi), and woodland jumping mouse (Napeozapus insignis). The red squirrel (Tamiasciurus hudsonicus) was indifferent to development. Small mammal diversity was highest on mixed shorelines at moderate levels of development. Species diversity appeared to respond positively to vegetative composition, edge effect, and irregularity of habitat. These characteristics were all dependent on the level of cottage development.

scholarly journals Adult-mediated connectivity and spatial population structure of sardine in the Bay of Biscay and Iberian coast

2019 ◽  
Vol 159 ◽  
pp. 62-74 ◽  
Author(s):  
Alexandra Silva ◽  
Susana Garrido ◽  
Leire Ibaibarriaga ◽  
Lionel Pawlowski ◽  
Isabel Riveiro ◽  
...  
Keyword(s):  
Population Structure ◽  
Bay Of Biscay ◽  
Spatial Population ◽  
Spatial Population Structure

Genetic isolation by distance and localized fjord population structure in Pacific cod (Gadus macrocephalus): limited effective dispersal in the northeastern Pacific Ocean

2009 ◽  
Vol 66 (1) ◽  
pp. 153-166 ◽  
Author(s):  
Kathryn Maja Cunningham ◽  
Michael Francis Canino ◽  
Ingrid Brigette Spies ◽  
Lorenz Hauser
Keyword(s):  
Population Structure ◽  
Pacific Ocean ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Puget Sound ◽  
Pacific Cod ◽  
Genetic Population ◽  
Pacific Cod Gadus Macrocephalus ◽  
Gadus Macrocephalus ◽  
Northeastern Pacific

Genetic population structure of Pacific cod, Gadus macrocephalus , was examined across much of its northeastern Pacific range by screening variation at 11 microsatellite DNA loci. Estimates of FST (0.005 ± 0.002) and RST (0.010 ± 0.003) over all samples suggested that effective dispersal is limited among populations. Genetic divergence was highly correlated with geographic distance in an isolation-by-distance (IBD) pattern along the entire coastal continuum in the northeastern Pacific Ocean (~4000 km; r2 = 0.83), extending from Washington State to the Aleutian Islands, and over smaller geographic distances for three locations in Alaska (~1700 km; r2 = 0.56). Slopes of IBD regressions suggested average dispersal distance between birth and reproduction of less than 30 km. Exceptions to this pattern were found in samples taken from fjord environments in the Georgia Basin (the Strait of Georgia (Canada) and Puget Sound (USA)), where populations were differentiated from coastal cod. Our results showed population structure at spatial scales relevant to fisheries management, both caused by limited dispersal along the coast and by sharp barriers to migration isolating smaller stocks in coastal fjord environments.

Evaluating Live trapping and Camera-based Indices of Small Mammal Density

2021 ◽  
Author(s):  
Mitchell Alan Parsons ◽  
ALISHIA ORLOFF ◽  
Laura Prugh
Keyword(s):  
Small Mammal ◽  
Abundant Species ◽  
Monitoring Methods ◽  
Density Estimates ◽  
Full Dataset ◽  
Live Trapping ◽  
Minimum Number ◽  
Capture Recapture ◽  
Two Indices ◽  
Best Fit

Density estimates are integral to wildlife management, but they can be costly to obtain. Indices of density may provide efficient alternatives, but calibration is needed to ensure the indices accurately reflect density. We evaluated several indices of small mammal density using live trapping and motion-activated cameras in Washington’s Cascade Mountains. We used linear regression to compare spatially-explicit capture recapture density estimates of mice, voles, and chipmunks to four indices. Two indices were based on live trapping (minimum number alive and number of captures per 100 trap nights) and two indices were based on photos from motion-activated cameras (proportion of cameras detecting a species and the number of independent detections). We evaluated how the accuracy of trap-based indices increased with trapping effort using subsets of the full dataset (n = 7 capture occasions per site). Most indices provided reliable indicators of small mammal density, and live trapping indices (R2=0.64 – 0.98) outperformed camera-based indices (R2=0.24 – 0.86). All indices performed better for more abundant species. The effort required to estimate each index varied, and indices that required more effort performed better. These findings should help managers, conservation practitioners, and researchers select small mammal monitoring methods that best fit their needs.

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