conservation.arizona.edu - red-bellied squirrels

Palmer, G. H., J. L, Koprowski, and T. Pernas. 2008. Tree squirrels as invasive species: conservation and management implications. Pp 273 - 282 in G. L. Witmer, W. C. Pitt, K.A. Fagerstone (eds.), Managing vertebrate invasive species: proceedings of an in

thackerk1 — Wed, 24 Jul 2019 22:02:20 +0000

Authors

Geoffrey H. Palmer

John L. Koprowski

Tony Pernas

The impact of invasive species on native biodiversity is increasing worldwide. Mammalian invaders are formidable ecological and economic threats, and tree squirrels are models of such challenges. We review the worldwide distribution of tree squirrel introductions and detail their nearly universal success. The biological characteristics of tree squirrels that enable success as invasive species are: high reproductive potential, high vagility, diverse food habits, ability to construct nests, and plasticity in human-impacted landscapes. We document costs and benefits of tree squirrel introductions, and discuss existing management strategies planned for some species. We focus on an introduced population of Mexican red-bellied squirrels (Sciurus aureogaster) found in Biscayne National Park, Florida, United States. Originally introduced to Elliot Key in 1938, the population expanded until Hurricane Andrew in 1992. Thought to be extirpated, recent sightings initiated a project to assess status and distribution within the Park. A field study has provided valuable information on potential and realized impacts that the squirrel population has on the native ecosystem that includes several species of conservation concern. Management strategies for Mexican red-bellied squirrels can be formed after research to develop prudent and effective means to meet the challenges that result from control measures to deal with this exotic species.

Additional Information

TREE SQUIRRELS AS INVASIVE SPECIES: CONSERVATION AND MANAGEMENT IMPLICA TIONS

Date of publication:

2007

Topics

invasive species

red-bellied squirrels

tree squirrel

management strategies

Palmer, G. H., J. L. Koprowski, and A. J. Pernas. 2013. Nest tree and site selection of an introduced population of red-bellied squirrels (Sciurus aureogaster). Journal of Mammalogy 94:1274-1281.

thackerk1 — Wed, 24 Jul 2019 21:30:22 +0000

Authors

Geoffrey H. Palmer

John L. Koprowski

Anthony J. Pernas

Nests play a crucial role in the life history of tree squirrels, and can be a critical component of their biology that enables them to be a successful invasive species. Red-bellied squirrels (Sciurus aureogaster) were introduced to Elliott Key, Florida, in the late 1930s, and spread to nearby islands. Red-bellied squirrels were believed extirpated by Hurricane Andrew in 1992, but were rediscovered on Elliott Key in 2005. In 2006 and 2007, we surveyed for squirrel nests and measured vegetation to evaluate forest characteristics associated with nest-site selection by squirrels, and compared these data to measurements collected at random locations. Squirrels placed nests in large trees with more canopy linkages in mixed-hardwood forest, and the nest trees were in areas with large trees, high tree density and canopy cover, and lower recent hurricane damage. Red-bellied squirrels selected characteristics of nest trees and forest structure in similar ways to individuals in their native range, and to other species of tree squirrels in general. Results from our research allowed land managers to assess possible management actions and provided important information for them to develop an effective management strategy. Park officials are currently working toward complete eradication of the introduced population of red-bellied squirrels from the Florida Keys. We suggest that behaviors of individuals in native ranges may elucidate patterns for individuals introduced to novel environments; however, we also caution that care must be taken in further extrapolation. Our findings emphasize the importance of understanding ecology of introduced species for effective management.

Additional Information

Nest tree and site selection of an introduced population of red-bellied squirrels (Sciurus aureogaster)

Date of publication:

2013

Topics

habitat selection

invasive species

Mexican gray squirrel

nesting behavior

species eradication

tree squirrel

red-bellied squirrels

Biscayne National Park

Palmer, G. H., J. L. Koprowski, and A. J. Pernas. 2014. Distribution and spread of an introduced insular population of red-bellied squirrels (Sciurus aureogaster) in Florida. Mammalia 78: 67-73

thackerk1 — Wed, 24 Jul 2019 21:24:17 +0000

Authors

Geoffrey H. Palmer

John L. Koprowski

Anthony J. Pernas

Introduced populations of species pose one of the greatest threats to the persistence of native species. Documentation of distribution, range expansion and habitat use of introduced populations are key components of developing effective management strategies for the control and eradication of invasive species. In 2006 and 2007, we surveyed four islands in Biscayne National Park for nests to evaluate the presence of red-bellied squirrels (Sciurus aureogaster) and the distribution and index of dispersion of their nests in the Florida Keys archipelago within the Atlantic Ocean. Red-bellied squirrels were initially introduced to Elliott Key, Florida, USA in in 1938. We documented evidence of squirrels on two additional islands, Sands Key and Old Rhodes Key, which adds to concerns of spread of this introduced squirrel to areas with endangered endemic insular mammals. Squirrel nests were documented only in mixed-hardwood forest, and nests had a clumped distribution within this forest type. Range expansion was a chief concern to the National Park Service, as continued spread could result in squirrels exiting the park, and prompted management action. Understanding nest site selection and distribution was critical for developing an eradication strategy for the introduced population of red-bellied squirrels from south Florida.

Additional Information

Distribution and spread of an introduced insular population of red-bellied squirrels (Sciurus aureogaster) in Florida

Date of publication:

2014

Topics

colonization

habitat selection

invasive species

red-bellied squirrels

species eradication