Aerial Mark-Recapture Estimates of Confined Mule Deer in Pinyon-Juniper Woodland

Bartmann, Richard M.; White, Gary C.; Carpenter, Len H.; Garrott, Robert A.

doi:10.2307/3801626

Cited by 79 publications

(67 citation statements)

References 4 publications

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“…Population estimates and 95% confidence limits were derived from the census results using the joint hypergeometric maximum likelihood estimator (JHE) (Bartmann et al 1987) in the NO-REMARK computer program (White 1996). In cases where the lower 95% confidence limit was below the actual number of caribou seen during census flights, we used the census result as the lower confidence limit.…”

Section: Population Sizes and Trendsmentioning

confidence: 99%

The role of predation in the decline and extirpation of woodland caribou

Wittmer

Sinclair

McLellan³

2005

Oecologia

281

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To select appropriate recovery strategies for endangered populations, we must understand the dynamics of small populations and distinguish between the possible causes that drive such populations to low numbers. It has been suggested that the pattern of population decline may be inversely density-dependent with population growth rates decreasing as populations become very small; however, empirical evidence of such accelerated declines at low densities is rare. Here we analyzed the pattern of decline of a threatened population of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada. Using information on the instantaneous rate of increase relative to caribou density in suitable winter foraging habitat, as well as on pregnancy rates and on causes and temporal distribution of mortalities from a sample of 349 radiocollared animals from 15 subpopulations, we tested 3 hypothesized causes of decline: (a) food regulation caused by loss of suitable winter foraging habitat, (b) predation-sensitive foraging caused by loss of suitable winter foraging habitat and (c) predation with caribou being secondary prey. Population sizes of caribou subpopulations ranged from < 5 to > 500 individuals. Our results showed that the rates of increase of these subpopulations varied from -0.1871 to 0.0496 with smaller subpopulations declining faster than larger subpopulations. Rates of increase were positively related to the density of caribou in suitable winter foraging habitat. Pregnancy rates averaged 92.4% +/-2.24 and did not differ among subpopulations. In addition, we found predation to be the primary cause of mortality in 11 of 13 subpopulations with known causes of mortality and predation predominantly occurred during summer. These results are consistent with predictions that caribou subpopulations are declining as a consequence of increased predation. Recovery of these woodland caribou will thus require a multispecies perspective and an appreciation for the influence of inverse density dependence on population trajectories.

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Section: Population Sizes and Trendsmentioning

confidence: 99%

The role of predation in the decline and extirpation of woodland caribou

Wittmer

Sinclair

McLellan³

2005

Oecologia

281

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“…This combination was particularly useful in terms of robust estimation given the low recapture probabilities for these hawksbill turtles. Current mark-resight methods have moved beyond a single focus on abundance estimation (Bartmann et al 1987, Arnason et al 1991, Neal et al 1993, Bowden & Kufeld 1995 and now more reliably allow for integrated estimation of survival and transition rates between observable and un ob servable states (Kendall et al 1995, 1997, Ken dall & Nichols 2002. This is important for evaluating the status of this Belizean hawksbill turtle population over time because it provides information on long-term prospects for the population and movements in and out of the forereef study area.…”

Section: Introductionmentioning

confidence: 99%

In-water assessments of sea turtles at Glover’s Reef Atoll, Belize

Strindberg¹,

Coleman²,

Perez³

et al. 2016

Endang. Species. Res.

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The decline of sea turtle populations in the Caribbean has led to intensive recovery efforts. In Belizean waters, hawksbill turtles are seemingly making a comeback. At Glover's Reef Atoll particularly, juvenile hawksbill turtles are found in the fore-reef habitat. The population status and dynamics of this foraging aggregation were assessed to inform conservation management and to ascertain the national and regional importance of this site. During 12 sampling periods from 2007 to 2013, turtles of all species were counted, captured, and tagged. For hawksbill turtles, the capture-recapture histories were combined with the counts using a mark-resight analysis under a robust design. This provided estimates of abundance as well as survival and transition rates. From 2009 onward, distance sampling was also used to estimate density and abundance of hawksbill turtles and the less frequently encountered green and loggerhead turtles. Distance sampling provided a more cost-effective estimation method for multiple species and another more precise source of abundance estimates for hawksbills. This is the first study known to use either markresight or distance sampling methods during snorkel surveys of sea turtles. It produced reasonably congruent abundance estimates of >1000 juvenile hawksbills and an order of magnitude less of green and loggerhead turtles. The mark-resight analysis estimated an apparent juvenile hawksbill survival probability of 0.975 (95% CI: 0.936−0.99), indicating that mortality factors are low. The Atoll provides important developmental habitat for juvenile hawksbills, contributing to the recovery of the species on the national and regional scale.

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“…Calculating abundance estimates from real-time aerial counts presents several recognized errors and inconsistencies (Bartmann et al, 1987;Freddy et al, 2004;White et al, 1989). The accuracy of real-time aerial counts can be influenced by species characteristics, viewing conditions, land cover, and the training and experience of the observer.…”

mentioning

confidence: 99%

Environmental Reviews and Case Studies: Applications of Unmanned Aircraft Systems (UAS) for Waterbird Surveys

Dulava

Bean

Richmond

2015

Environmental Practice

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Utilizing unmanned aircraft systems (UAS) can be an efficient and repeatable means of surveying wildlife, especially waterbirds. As with any technology in its infancy, case studies offer opportunities to explore drawbacks and limitations, both anticipated and unanticipated. We examined the relationship between flight altitude and camera focal length on bird identification. We then conducted a post-hoc analysis to examine the effect of flight altitude on bird flushing behavior. We flew UAS missions at three locations in California and Nevada to assess the use of UAS for censusing non-nesting waterbirds. A minimum pixel resolution of approximately 5 mm was needed be able to identify most waterbird species from imagery. Sensors needed to be carefully calibrated in order to obtain images of sufficient quality to identify waterbirds over open water. Our results suggest that gas-powered UAS may result in increased rates of flushing at low flight altitudes for some waterbirds. With careful design of surveys and processing workflow, UAS show promise for censusing and monitoring waterbirds. Environmental Practice 17: 201-210 (2015)

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Aerial Mark-Recapture Estimates of Confined Mule Deer in Pinyon-Juniper Woodland

Cited by 79 publications

References 4 publications

The role of predation in the decline and extirpation of woodland caribou

The role of predation in the decline and extirpation of woodland caribou

In-water assessments of sea turtles at Glover’s Reef Atoll, Belize

Environmental Reviews and Case Studies: Applications of Unmanned Aircraft Systems (UAS) for Waterbird Surveys

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