conservation.arizona.edu - small mammals

Merrick, M.J., J.L. Koprowski, R.N.Gwinn, G.H. Palmer, C.A. Zugmeyer. 2011. Surveys to determine the status of red squirrels in Guadalupe Mountains National Park, Texas. Southwestern Naturalist. 56: 24-28.

thackerk1 — Tue, 23 Jul 2019 23:33:49 +0000

Authors

Melissa J. Merrick

John L. Koprowski

R. Nathan Gwinn

Geoffrey H. Palmer

Claire A. Zugmeyer

The Pinaleńo Mountains of southeastern Arizona contain the southernmost population of red squirrels (Tamiasciurus hudsonicus) in North America. Red squirrels historically inhabited the Guadalupe Mountains in Trans-Pecos Texas during the Pleistocene and the possibility that red squirrels currently persist has been suggested by several biologists visiting the upper-elevation forests. Herein, we report results of an assessment of small mammals in coniferous forest where we used observational line transects, playback calls, and live trapping to determine status of red squirrels. We surveyed 132 ha of coniferous forest along 8.9 km of transects and observed and found evidence of 10 species of mammals. We detected no evidence of red squirrels inhabiting high-elevation coniferous forest.

Additional Information

STATUS OF RED SQUIRRELS IN GUADALUPE MOUNTAINS NATIONAL PARK, TEXAS

Date of publication:

2011

Topics

red squirrel

Pinaleño Mountains

assessment

small mammals

coniferous forest

Novel location data reveal spatiotemporal strategies used by a central-place forager

thackerk1 — Mon, 22 Jul 2019 18:36:53 +0000

Authors

Kira L. Hefty

Kelley M. Stewart

Central-place foragers in risky landscapes experience conflicting behavioral demands that they must balance by appropriately adjusting how they move throughout their home ranges. We used novel mini-GPS technology and time local convex hull analyses to determine how golden-mantled ground squirrels (Callospermophilus lateralis) use a spatiotemporal strategy to optimize foraging early in the year when individuals are in an energy deficit. By using serial correlation from GPS data, we could better understand how individuals use a time management strategy influenced by distance traveled from the burrow, location of food patches, location of refuge patches, and vegetative cover type. Individuals maximized time spent in food patches rather than in travel corridors or at the burrow, suggesting the need to forage was prioritized. Individuals spent more time at patches farther from the burrow relative to nearer patches, potentially as a function of intermittent antipredator vigilance activity and energy optimization. Individuals also had high rates of revisitation, but low visit duration, in risky canopy cover types, suggesting that individuals used areas of low vegetative understory cover to travel efficiently between high- value food patches. Increased predation risk incurred while traveling in these open areas was possibly offset by use of refuges. Understanding these spatiotemporal movement patterns and how they relate to dynamic intrinsic and extrinsic demands has the potential to redefine optimal foraging behavior and better inform management and conservation practices.

Additional Information

Novel location data reveal spatiotemporal strategies used by a central-place forager

Date of publication:

2018

Topics

GPS

movement behavior

optimal foraging

small mammals

spatiotemporal

Research Categories

Behavioral Ecology Spatial Ecology

Edelman, A. J., J. L. Koprowski, and J. L. Edelman. 2005. Kleptoparasitic behavior and species richness at Mt. Graham red squirrel middens. USDA Forest Service Proceedings RMRS-P-36: 395 - 398.

thackerk1 — Tue, 25 Jun 2019 01:31:05 +0000

Authors

Andrew J. Edelman

John L. Koprowski

Jennifer L. Edelman

We used remote photography to assess the frequency of inter- and intra-specific klepto- parasitism and species richness at Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis) middens. Remote cameras and conifer cones were placed at occupied and unoccupied middens, and random sites. Species richness of small mammals was higher at red squirrel middens than random sites. Abert’s squirrels, potential kleptoparasites, were recorded only at unoccupied mid- dens and random sites. Non-resident red squirrels were most common at unoccupied middens and rare at occupied middens and random sites. Inter- and intra-specific kleptoparasitism of red squirrel middens appears uncommon likely due to territorial behavior.

Additional Information

Kleptoparasitic Behavior and Species Richness at Mt. Graham Red Squirrel Middens

Date of publication:

2005

Topics

Mount Graham Red Squirrel

kleptoparasitism

inter-specific

intra-specific

conifer cones

small mammals

middens

Abert’s squirrels

territorial behavior

species richness

Barrier effects of roads on an endangered forest obligate: influences of traffic, road edges, and gaps

thackerk1 — Thu, 20 Jun 2019 22:59:51 +0000

Authors

Hsiang Ling Chen

John L. Koprowski

Habitat fragmentation and destruction caused by development of infrastructure such as roads threaten biodiversity. Roads act as barriers by impeding animal movements and restricting space use. Understanding factors that influence barrier effects is important to discern the impacts of habitat fragmentation and to develop appropriate mitigations. We combined telemetry and demographic data in 2008 to 2012 with remote sensing imagery to investigate barrier effects of forest roads and assess effects of traffic, road edges, and canopy gaps on space use of an endangered, endemic forest obligate, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis). We mapped low to high traffic roads, road edges, canopy gaps, and random lines in forests to serve as references. We determined if red squirrels included these linear features in their total and core home ranges, and used this metric as an indicator of crossing and preference for habitat adjacent to the linear features. Forest roads acted as barriers regardless of traffic volume and had long-term impacts on animal space use. Animals did not avoid entering roadside areas, and probability of crossing linear features in the forest was not affected by distance to roads. In contrast, greater canopy cover increased probability of crossing, and gaps in canopy impeded animal movements. Higher likelihood of road crossing was associated with more variable tree height and mating activity. We demonstrated that narrow forest roads with low traffic volume were barriers for forest dependent species, and suggest that gap avoidance inhibits road crossings.

Additional Information

Biological Conservation 199:33-40.

Date of publication:

2016

Topics

habitat fragmentation

gap avoidance

forest roads

forest structure

small mammals

road impacts

Research Categories

Behavioral Ecology Disturbance Ecology Sky Islands Threatened and Endangered Species