conservation.arizona.edu - reintroduction

Wood, D. J. A., J. L. Koprowski, and P. W. W. Lurz. 2007. Tree squirrel introductions: A theoretical approach with population viability analysis. Journal of Mammalogy 88(5): 1271-1279.

thackerk1 — Tue, 30 Jul 2019 21:29:20 +0000

Authors

David J. A. Wood

John L. Koprowski

Peter W. W. Lurz

Reintroduction efforts require knowledge of how many animals are needed for successful establishment. Population viability analysis can be used to predict trajectories of introduced populations and tree squirrels provide an ideal model system to investigate this challenge. Conservation action is needed because more than 80% of species of tree squirrels are of precarious conservation status in some portion of their range. We combined data from closely related species of tree squirrels and used VORTEX to determine how many squirrels are needed to successfully establish populations of 6 species (Sciurus aberti, S. carolinensis, S. niger, S. granatensis, S. vulgaris, and Tamiasciurus hudsonicus). We ran multiple simulations to account for between- patch differences in breeding success (resource availability) and variation between years in different habitats. In the best-case scenarios, populations could be successfully established with fewer than 35 individuals for all species and as few as 15 for a subset of species. Empirical evidence from introductions of tree squirrels supports our simulation results, with 93% of populations of greater than 10 squirrels surviving more than 50 years. With relatively few individuals needed for establishing new squirrel populations, reintroductions are feasible and useful as a buffer for imperiled species.

Additional Information

TREE SQUIRREL INTRODUCTION: A THEORETICAL APPROACH WITH POPULATION VIABILITY ANALYSIS

Date of publication:

2007

Topics

reintroduction

tree squirrels

extinction

VORTEX

Hale, S. L., J. L. Koprowski, and H. Hicks. 2013. Review of black-tailed prairie dog reintroduction strategies and site selection: Arizona reintroduction. In Gottfried, Gerald J.; Ffolliott, Peter F.; Gebow, Brooke S.; Eskew, Lane G.; Collins, Loa C., com

thackerk1 — Mon, 22 Jul 2019 18:05:30 +0000

Authors

Sarah L. Hale

John L. Koprowski

Holly Hicks

The black-tailed prairie dog (Cynomys ludovicianus) was once widely distributed throughout the western United States; however, anthropogenic influences have reduced the species’ numbers to 2 percent of historical populations. Black-tailed prairie dogs are described as a keystone species in the grassland ecosystem, and provide many unique services, including burrows for other species (e.g. burrowing owls [Athene cunicularia] and rattlesnakes [Crotalus spp.]), nutrient rich soil that, in turn, provides rich vegetationfor grazers, and food for many carnivores and birds of prey. Several efforts have been made to reestablishthis species to its historical range. In southeastern Arizona, a recent reintroduction effort was built upon work of scientists that identified potential suitable areas with characteristics similar to those of existing prairie dog colonies in Mexico. Prairie dogs were first translocated to the sites in 2008, and individuals still remain on the landscape today. We compare this to other reestablishment efforts, and provide suggestions on ways to increase success of future reintroductions.

Additional Information

Review of Black-Tailed Prairie Dog Reintroduction Strategies and Site Selection: Arizona Reintroduction

Date of publication:

2013

Topics

black-tailed prairie dog

keystone species

population reduction

reintroduction

reestablishment

Ecosystem-level effects of keystone species reintroduction: a literature review

thackerk1 — Thu, 27 Jun 2019 23:42:45 +0000

Authors

Sarah L. Hale

John L. Koprowski

The keystone species concept was introduced in 1969 in reference to top‐down regulation of communities by predators, but has expanded to include myriad species at different trophic levels. Keystone species play disproportionately large, important roles in their ecosystems, but human‐wildlife conflicts often drive population declines. Population declines have resulted in the necessity of keystone species reintroduction; however, studies of such reintroductions are rare. We conducted a literature review and found only 30 peer‐reviewed journal articles that assessed reintroduced populations of keystone species, and only 11 of these assessed ecosystem‐level effects following reintroduction. Nine of 11 publications assessing ecosystem‐level effects found evidence of resumption of keystone roles; however, these publications focus on a narrow range of species. We highlight the deficit of peer‐reviewed literature on keystone species reintroductions, and draw attention to the need for assessment of ecosystem‐level effects so that the presence, extent, and rate of ecosystem restoration driven by keystone species can be better understood.

Additional Information

Restoration Ecology

Date of publication:

2018

Topics

ecosystem restoration

keystone species

reintroduction

population declines

ecosystem-level effects

Research Categories

Population Ecology Threatened and Endangered Species

Kangaroo rat foraging in proximity to a colony of reintroduced black-tailed prairie dogs

thackerk1 — Thu, 27 Jun 2019 21:57:47 +0000

Authors

Kirsten M. Fulgham

John L. Koprowski

We examined the indirect effects of reintroduced black-tailed prairie dogs (Cynomys ludovicianus) on resident kangaroo rat (Dipodomys) populations. We used the Giving-up Density theory to quantify kangaroo rat foraging on a black-tailed prairie dog colony vs. foraging near the colony edge or in the surrounding native habitat. This approach allowed us to assess the influence of black-tailed prairie dogs on kangaroo rat foraging activity. Our results showed a greater foraging preference off-colony in most seasons. Kangaroo rats visited off-colony feeding trays more frequently and collected a greater mean mass of seed as well. This indicated that kangaroo rats perceived the area off the prairie dog colony as having a lower foraging cost than the on-colony or colony edge locations. Our data suggest that from the perspective of the seed-eating kangaroo rat, the colony is not viewed as high quality habitat. Both prairie dogs and kangaroo rats have been described as keystone modifiers in grassland ecosystems. What impact the reintroduction and management of one keystone species might have on another keystone species deserves additional consideration as we attempt to restore arid grassland ecosystems.

Additional Information

The Southwestern Naturalist 61:194-202.

Date of publication:

2016

Topics

reintroduction

black-tailed prairie dog

kangaroo rat

Giving-up Density theory

foraging

keystone species

Research Categories

Behavioral Ecology Threatened and Endangered Species