7 results on '"O'CONNELL, JR., ALLAN F."'
Search Results
2. Managing Native Predators: Evidence from a Partial Removal of Raccoons (Procyon lotor) on the Outer Banks of North Carolina, USA.
- Author
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STOCKING, JESSICA J., SIMONS, THEODORE R., PARSONS, ARIELLE W., and O'CONNELL JR., ALLAN F.
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RACCOON ,PREDATION ,WATER bird conservation ,AMERICAN oystercatcher ,NEST building ,HUMAN ecology ,BIRDS - Abstract
Raccoons (Procyon lotor) are important predators of ground-nesting species in coastal systems. They have been identified as a primary cause of nest failure for the American Oystercatcher (Haematopus palliatus) throughout its range. Concerns over the long-term effects of raccoon predation and increased nest success following a hurricane inspired a mark-resight study of the raccoon population on a barrier island off North Carolina, USA. Approximately half of the raccoons were experimentally removed in 2008. Nests (n = 700) were monitored on two adjacent barrier islands during 2004-2013. Daily nest survival estimates were highest for 2004 (0.974 ± 0.005) and lowest for 2007 and 2008 (0.925 ± 0.009 and 0.925 ± 0.010, respectively). The only model in our candidate set that received any support included island and time of season, along with a diminishing effect of the hurricane and a constant, 5-year effect of the raccoon removal. For both hurricane and raccoon removal, however, the support for island-specific effects was weak (β = -0.204 ± 0.116 and 0.146 ± 0.349, respectively). We conclude that either the raccoon reduction was inadequate, or factors other than predation cause more variation in nest success than previously recognized. A multi-faceted approach to management aimed at reducing nest losses to storm overwash, predation, and human disturbance is likely to yield the largest population level benefits. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
3. Multi-scale occupancy estimation and modelling using multiple detection methods.
- Author
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Nichols, James D., Bailey, Larissa L., O'Connell Jr, Allan F., Talancy, Neil W., Campbell Grant, Evan H., Gilbert, Andrew T., Annand, Elizabeth M., Husband, Thomas P., and Hines, James E.
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ANIMAL species ,STRIPED skunk ,RED salamander ,SAMPLING (Process) ,ESTIMATION theory ,PROBABILITY theory - Abstract
1. Occupancy estimation and modelling based on detection–nondetection data provide an effective way of exploring change in a species’ distribution across time and space in cases where the species is not always detected with certainty. Today, many monitoring programmes target multiple species, or life stages within a species, requiring the use of multiple detection methods. When multiple methods or devices are used at the same sample sites, animals can be detected by more than one method. 2. We develop occupancy models for multiple detection methods that permit simultaneous use of data from all methods for inference about method-specific detection probabilities. Moreover, the approach permits estimation of occupancy at two spatial scales: the larger scale corresponds to species’ use of a sample unit, whereas the smaller scale corresponds to presence of the species at the local sample station or site. 3. We apply the models to data collected on two different vertebrate species: striped skunks Mephitis mephitis and red salamanders Pseudotriton ruber. For striped skunks, large-scale occupancy estimates were consistent between two sampling seasons. Small-scale occupancy probabilities were slightly lower in the late winter/spring when skunks tend to conserve energy, and movements are limited to males in search of females for breeding. There was strong evidence of method-specific detection probabilities for skunks. As anticipated, large- and small-scale occupancy areas completely overlapped for red salamanders. The analyses provided weak evidence of method-specific detection probabilities for this species. 4. Synthesis and applications. Increasingly, many studies are utilizing multiple detection methods at sampling locations. The modelling approach presented here makes efficient use of detections from multiple methods to estimate occupancy probabilities at two spatial scales and to compare detection probabilities associated with different detection methods. The models can be viewed as another variation of Pollock's robust design and may be applicable to a wide variety of scenarios where species occur in an area but are not always near the sampled locations. The estimation approach is likely to be especially useful in multispecies conservation programmes by providing efficient estimates using multiple detection devices and by providing device-specific detection probability estimates for use in survey design. [ABSTRACT FROM AUTHOR]
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- 2008
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4. DEER EXPOSED TO EXCEPTIONALLY HIGH CONCENTRATIONS OF LEAD NEAR THE CONTINENTAL MINE IN IDAHO, USA.
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BEYER, W. NELSON, GASTON, GREG, BRAZZLE, ROY, O'CONNELL, JR., ALLAN F., and AUDET, DAN J.
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LEAD & the environment ,ABANDONED mined lands reclamation ,GEOPHAGY ,ENVIRONMENTAL engineering ,MULE deer ,MOOSE ,CONTINENTAL Mine (Idaho) - Abstract
Habitat surrounding the inactive Continental Mine in northern Idaho, USA, supports bear (Ursus arctos, Ursus americanus), moose (Alces alces), elk (Cervus elaphus), woodland caribou (Rangifer tarandus caribou), and abundant mule (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus). Tailings on the mining site were capped and remediated in 2003 to reduce environmental exposure of surrounding soil and sediments of Blue Joe Creek, downslope of the mine. Before capping, the mean Pb concentration in deer pellets collected on-site was 920 mg/kg of Pb (dry wt). This exposure, if chronic, would be comparable to an exposure that could be lethal to cattle or horses. Surprisingly, the mean pellet Pb concentration of 950 mg/kg in 2004 was as high as it was before remediation, and it was related to a high rate of soil ingestion. Mean soil content of the pellets collected from the capped site in 2004 was 22% dry weight, estimated from the acid-insoluble ash, a marker of soil ingestion. Clumps of sand and bits of rock were observed inside some of the pellets, and Pb concentrations in the pellets were correlated (p < 0.05) with soil content. Although terrestrial risk assessments generally estimate exposure from diets and from incidentally ingested soil, the deer at this site were directly ingesting contaminated soil or mining waste. The mean Pb concentration of this ingested soil was estimated as 6,700 mg/kg and the maximum as 25,000 mg/kg, well above the Pb concentrations measured in the remediated cap. The deer seemed to be ingesting soil or mining waste from one or more small but highly contaminated sources located beyond the remediated cap. [ABSTRACT FROM AUTHOR]
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- 2007
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5. Estimating Site Occupancy and Detection Probability Parameters for Meso- And Large Mammals in a Coastal Ecosystem.
- Author
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O'Connell Jr., Allan F., Talancy, Neil W., Bailey, Larissa L., Sauer, John R., Cook, Robert, and Gilbert, Andrew T.
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MAMMAL population estimates , *COASTAL ecology , *ANIMAL populations , *WILDLIFE management - Abstract
Large-scale, multispecies monitoring programs are widely used to assess changes in wildlife populations but they often assume constant detectability when documenting species occurrence. This assumption is rarely met in practice because animal populations vary across time and space. As a result, detectability of a species can be influenced by a number of physical, biological, or anthropogenic factors (e.g., weather, seasonality, topography, biological rhythms, sampling methods). To evaluate some of these influences, we estimated site occupancy rates using species-specific detection probabilities for meso- and large terrestrial mammal species on Cape Cod, Massachusetts, USA. We used model selection to assess the influence of different sampling methods and major environmental factors on our ability to detect individual species. Remote cameras detected the most species (9), followed by cubby boxes (7) and hair traps (4) over a 13-month period. Estimated site occupancy rates were similar among sampling methods for most species when detection probabilities exceeded 0. 15, but we question estimates obtained from methods with detection probabilities between 0.05 and 0.15, and we consider methods with lower probabilities unacceptable for occupancy estimation and inference. Estimated detection probabilities can be used to accommodate variation in sampling methods, which allows for comparison of monitoring programs using different protocols. Vegetation and seasonality produced species-specific differences in detectability and occupancy, but differences were not consistent within or among species, which suggests that our results should be considered in the context of local habitat features and life history traits for the target species. We believe that site occupancy is a useful state variable and suggest that monitoring programs for mammals using occupancy data consider detectability prior to making inferences about species distributions or population change. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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6. STATUS AND HABITAT RELATIONSHIPS OF NORTHERN FLYING SQUIRRELS ON MOUNT DESERT ISLAND, MAINE.
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O'Connell Jr., Allan F., Servello, Frederick A., Higgins, Jennifer, and Halteman, William
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FLYING squirrels , *SQUIRRELS - Abstract
Presents a study that determined the status and the distribution of the northern and southern flying squirrels on Mount Desert Island, Maine. Areas where northern flying squirrels were widely distributed; Correlation between home range size and the abundance of mast-producing trees; Indication of the interactions between northern and southern flying squirrels.
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- 2001
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7. Habitat use and distribution of the mice Peromyscus leucopus and P. maniculatus on Mount Desert Island, Maine
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Garman, Steven L., Connery, Judith Hazen, and O'Connell, Jr., Allan F.
- Published
- 1994
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