Relationship between deer mouse population parameters and dieldrin contamination in the Rocky Mountain Arsenal National Wildlife Refuge

1998 ◽  
Vol 76 (2) ◽  
pp. 243-250 ◽  
Author(s):  
Daniel L Allen ◽  
David L Otis
Keyword(s):  
Deer Mouse ◽  
Survival Rates ◽  
Rocky Mountain ◽  
Chemical Exposure ◽  
Contaminated Sites ◽  
Additional Stress ◽  
National Wildlife Refuge ◽  
Mouse Population ◽  
Wildlife Refuge ◽  
Rocky Mountain Arsenal

A small-mammal capture-recapture study was conducted in the Rocky Mountain Arsenal National Wildlife Refuge to quantify the effects of soil contamination with dieldrin on demographic parameters of deer mouse (Peromyscus maniculatus) populations. Increased dieldrin concentrations were significantly associated with larger deer mouse populations, although the size of populations on contaminated sites decreased during the study. The most parsimonious model for estimating survival rates was one in which survival was a decreasing function of dieldrin concentration. A significantly higher proportion of female deer mice in the populations residing on the more highly contaminated sites exhibited signs of reproductive activity. Development of genetic resistance in P. maniculatus to chronic chemical exposure is suggested as a possible mechanism responsible for the species' observed dominance and relatively high densities on contaminated sites. Under the additional stress of unfavorable environmental conditions, however, these populations may suffer disproportionately greater mortality. The design and analytical methods presented offer a rigorous statistical approach to assessing the effects of environmental contamination on small mammals at the population level.

A Markov Decision Process for Managing Habitat for Florida Scrub-Jays

2011 ◽  
Vol 2 (2) ◽  
pp. 234-246 ◽  
Author(s):  
Fred A. Johnson ◽  
David R. Breininger ◽  
Brean W. Duncan ◽  
James D. Nichols ◽  
Michael C. Runge ◽  
...  
Keyword(s):  
Transition Probabilities ◽  
Survival Rates ◽  
Monitoring Program ◽  
Optimal Management ◽  
Prescribed Burn ◽  
National Wildlife Refuge ◽  
Florida Scrub ◽  
Wildlife Refuge ◽  
Management Actions ◽  
Optimal Action

Abstract Florida scrub-jays Aphelocoma coerulescens are listed as threatened under the Endangered Species Act due to loss and degradation of scrub habitat. This study concerned the development of an optimal strategy for the restoration and management of scrub habitat at Merritt Island National Wildlife Refuge, which contains one of the few remaining large populations of scrub-jays in Florida. There are documented differences in the reproductive and survival rates of scrub-jays among discrete classes of scrub height (<120 cm or “short”; 120–170 cm or “optimal”; >170 cm or “tall”; and a combination of tall and optimal or “mixed”), and our objective was to calculate a state-dependent management strategy that would maximize the long-term growth rate of the resident scrub-jay population. We used aerial imagery with multistate Markov models to estimate annual transition probabilities among the four scrub-height classes under three possible management actions: scrub restoration (mechanical cutting followed by burning), a prescribed burn, or no intervention. A strategy prescribing the optimal management action for management units exhibiting different proportions of scrub-height classes was derived using dynamic programming. Scrub restoration was the optimal management action only in units dominated by mixed and tall scrub, and burning tended to be the optimal action for intermediate levels of short scrub. The optimal action was to do nothing when the amount of short scrub was greater than 30%, because short scrub mostly transitions to optimal height scrub (i.e., that state with the highest demographic success of scrub-jays) in the absence of intervention. Monte Carlo simulation of the optimal policy suggested that some form of management would be required every year. We note, however, that estimates of scrub-height transition probabilities were subject to several sources of uncertainty, and so we explored the management implications of alternative sets of transition probabilities. Generally, our analysis demonstrated the difficulty of managing for a species that requires midsuccessional habitat, and suggests that innovative management tools may be needed to help ensure the persistence of scrub-jays at Merritt Island National Wildlife Refuge. The development of a tailored monitoring program as a component of adaptive management could help reduce uncertainty about controlled and uncontrolled variation in transition probabilities of scrub-height and thus lead to improved decision making.

Examining Restoration Goals at a Former Military Site: Rocky Mountain Arsenal, Colorado

2014 ◽  
Vol 9 (3) ◽  
pp. 288-315 ◽  
Author(s):  
David G. Havlick ◽  
Marion Hourdequin ◽  
Matthew John
Keyword(s):  
Land Use ◽  
Reference Conditions ◽  
Rocky Mountain ◽  
National Wildlife Refuge ◽  
Native Prairie ◽  
Citizen Groups ◽  
Restoration Work ◽  
Visitor Survey ◽  
Rocky Mountain Arsenal ◽  
Cultural Features

Identifying appropriate restoration goals has long posed a challenge in ecological restoration. The task becomes even more difficult in settings with diverse land use histories. After two decades of remediation, a former chemical weapons facility near Denver, Colorado, has become a national wildlife refuge. Restoration efforts have isolated contaminants and restored bison and native prairie, but the site's complex history invites a deeper consideration of reference conditions. This article presents data from a visitor survey and interviews with land managers and citizen groups to examine conceptions of historical fidelity at this site. Results indicate that visitors and land managers orient toward restoration that features a traditional reference condition. Citizen groups point to restoration of cultural features as the highest priorities. This research highlights disparities between constituencies and suggests that restoration work itself may shape values that inform visitors and affirm how a landscape ought to exist.

National wildlife refuge visitor survey 2012--Individual refuge results

Data Series ◽  
10.3133/ds754 ◽  
2013 ◽  
Author(s):  
Alia M. Dietsch ◽  
Natalie R. Sexton ◽  
Lynne M. Koontz ◽  
Shannon J. Conk
Keyword(s):  
National Wildlife Refuge ◽  
Wildlife Refuge ◽  
Visitor Survey

Archive of bathymetry and backscatter data collected in 2014 nearshore Breton and Gosier Islands, Breton National Wildlife Refuge, Louisiana

Data Series ◽  
2016 ◽  
Author(s):  
Nancy T. DeWitt ◽  
Jake J. Fredericks ◽  
James G. Flocks ◽  
Jennifer L. Miselis ◽  
Stanley D. Locker ◽  
...  
Keyword(s):  
National Wildlife Refuge ◽  
Wildlife Refuge
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