conservation.arizona.edu - habitat use

Palmer, R. R., and J. L. Koprowski. 2014. Feeding behavior and activity patterns of Amazon red squirels. Mammalia 78: 303-313.

thackerk1 — Wed, 24 Jul 2019 22:25:41 +0000

Authors

Rosa R. Palmer

John L. Koprowski

Foraging sites are important for the survival of animals. Individuals cue on characteristics of the forest that offer enough food resources and also provide safety. During June and July of 2009 and 2010, we studied northern and southern Amazon red squirrels (Sciurus igniventris, S. spadiceus) to determine what forest characteristics were associated with feeding sites. We examined habitat use at three levels: vegetation community where feeding sign was located, site characteristics of the forest immediately surrounding the feeding sign, and the tree exhibiting feeding sign. We measured the site characteristics inside a 10-m radius circular plot, the physical characteristics of the tree exhibiting feeding sign, and the same variables at random locations for comparison. Because there is lack of knowledge about these squirrels, we also conducted focal observations to study their behavior. Squirrels use mainly high and low restinga and selected Astrocaryumand Attalea palm trees that were taller and larger com- pared with random locations. Squirrels used all vertical strata of the forest, and the main behaviors observed were travel and forage. Behaviors occurred similarly across the day but differed by vertical strata. Although squirrels used vegetation communities different than available and selected for tree characteristics, site characteristics did not appear to be important in contrast with other tree squirrel species.

Additional Information

Feeding behavior and activity patterns of Amazon red squirrels

Date of publication:

2014

Topics

foraging behavior

habitat use

palm trees

Northern Amazon red squirrel

southern Amazon red squirrel

Leonard, K. M. and J. L. Koprowski. 2009. A comparison of habitat use and demography of red squirrels at the southern edge of their range. American Midland Naturalist 162: 132-145.

thackerk1 — Tue, 23 Jul 2019 22:17:11 +0000

Authors

Kathrine M. Leonard

John L. Koprowski

Populations at the edge of their geographic range may demonstrate different population dynamics from central populations. Endangered Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis), endemic to southeastern Arizona, represent the southernmost red squirrel population and are found at lower densities than conspecifics in the center of the range. To determine if differences are due to conditions at the southern periphery of the range, we compared habitat characteristics, demography, body mass, space use and nesting behavior with another subspecies located at the southern edge of the range, the Mogollon red squirrel (T. h. mogollonensis). We found that mean and minimum daily temperatures were higher at Mt. Graham whereas maximum temperatures were higher in the White Mountains, male Mogollon red squirrels were heavier than male Mt. Graham red squirrels in all seasons and female Mogollon red squirrels were slightly heavier than female Mt. Graham red squirrels in spring, proportion of squirrels in reproductive condition was lower in female Mogollon red squirrels, Mogollon red squirrels had smaller home ranges, used different types of nests and traveled less distance to nest than Mt. Graham red squirrels. There were no differences in annual rainfall, seedfall, habitat characteristics or survival between mountain ranges. Localized conditions appear to account for the disparity between populations. These differences demonstrate the importance of evaluating attributes of peripheral populations for maximizing persistence and intraspecific diversity.

Additional Information

A Comparison of Habitat Use and Demography of Red Squirrels at the Southern Edge of Their Range

Date of publication:

2009

Topics

Mount Graham Red Squirrel

Mongollon red squirrel

habitat use

body mass

nesting behavior

Doumas, S. L., J. L. Koprowski, and W. O. Noble. 2016. Landscape-level assessment of Abert's squirrel and red squirrel in mixed conifer forest. The Southwestern Naturalist 60:240-246.

thackerk1 — Tue, 25 Jun 2019 00:36:36 +0000

Authors

Sandra L. Doumas

John L. Koprowski

William O. Noble

We examined feeding sign of Abert’s squirrels (Sciurus aberti) and red squirrels (Tamiasciurus hudsonicus) each spring 2005–2009 in mixed conifer forests in northern Arizona, USA. We used high- resolution aerial photographs to assess vegetation characteristics where feeding sign surveys were conducted and analyzed the association of feeding sign frequency to vegetation characteristics to compare and contrast species habitat use. At the landscape level, we found considerable overlap in characteristics of forests used by the two species of native tree squirrels. Red squirrels used denser forests with fewer and smaller gaps than do Abert’s squirrels, and Abert’s squirrels used more ponderosa pine (Pinus ponderosa) than do red squirrels.

Additional Information

Landscape-level assessment of Abert's Squirrel and Red Squirrel in Mixed Conifer Forest

Date of publication:

2015

Topics

Abert’s squirrels

red squirrels

feeding signs

mixed conifer forests

habitat use