Evaluation of Mark-Resight Model Assumptions for Estimating Mountain Sheep Numbers

Neal, Andrea K.; White, Gary C.; Gill, R. Bruce; Reed, Dale F.; Olterman, James Howard

doi:10.2307/3809268

Cited by 78 publications

(82 citation statements)

References 13 publications

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“…Monte Carlo simulations suggested that an increased proportion of the population being marked would increase the precision of our population estimates. This is not surprising and was reported earlier (Neal et al, 1993) using the same Monte Carlo simulation procedures.…”

Section: Survey Recommendationssupporting

confidence: 86%

“…We used the program NOREMARK (White, 1996) to estimate abundance, for both the AH and AWB, by fitting the data to a joint hypergeometric distribution (Neal et al, 1993). Given the relatively short time frame between marking and the resighting surveys we assumed the populations were both demographically and geographically closed (i.e., no animals died and no animals left or entered the study area).…”

Section: Discussionmentioning

confidence: 99%

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Using temporary dye marks to estimate ungulate population abundance in southwest Yukon, Canada

Hegel

Russell²,

Jung³

2012

Ran

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Abstract:We describe the protocols of two mark-resight abundance surveys, using temporary dye-marks, for the Aishihik woodland caribou (Rangifer tarandus caribou) and wood bison (Bison bison athabascae) populations (herds) in the southwest Yukon Territory, Canada. We also provide recommendations based on experiences from these surveys for biologists and managers considering this approach. The Aishihik woodland caribou herd was the focus of intensive management in the 1990s aimed at recovering the herd. Following recovery activities, a target size of 2000 animals was determined and the Champagne-Aishihik Traditional Territory Community-Based Wildlife Management Plan recommended an estimate of the herd's size be completed before the year 2013. We used an aerial mark-resight approach to estimate the herd's size in March 2009. Caribou (n = 59) were marked from a helicopter with temporary dye, delivered via a CO 2 -powered rifle. Two independent resighting sessions were subsequently carried out via helicopter. The herd was estimated at 2044 animals (90% CI: 1768 -2420) with an overall resighting rate of 0.47. The mean annual growth rate (λ) of the herd from 1997 -2009 was 1.05 (SE = 0.01). The Aishihik wood bison herd was estimated at 1151 (90% CI: 998 -1355). Our study suggests that ungulates temporarily marked with dye can be successfully used to obtain statistically sound population estimates.

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Section: Survey Recommendationssupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Using temporary dye marks to estimate ungulate population abundance in southwest Yukon, Canada

Hegel

Russell²,

Jung³

2012

Ran

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“…These findings suggest that this estimator might also be efficiently applied to other species living in forests and within social groups, e.g., wild boar (Kaminski et al 2005). Regarding the narrower CI obtained with MM, Neal et al (1993) showed that CI coverage performed poorly (i.e., is too narrow) for this estimator. Despite improvements brought to MM (Gardner and Mangel 1996), Neal et al (1993) and White and Shenk (2001) suggested the use of Bowden's estimator to be preferred.…”

Section: Population Size Estimatorsmentioning

confidence: 93%

“…Both estimators require individual and proper identification of marked animals during sightings. Finally, both models allow a sample drawn with replacement (Seber 1982), so that marked animals might be seen more than once on a survey and admit variability in sighting frequencies of marked animals (Minta and Mangel 1989;Neal et al 1993;Bowden and Kufeld 1995;White 1996). Concerning unmarked animals, only the sum of their sightings (S u ) needs to be known.…”

Section: Resightsmentioning

confidence: 99%

Estimating wild boar (Sus scrofa) abundance and density using capture–resights in Canton of Geneva, Switzerland

et al. 2007

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We estimated wild boar abundance and density using capture-resight methods in the western part of the Canton of Geneva (Switzerland) in the early summer from 2004 to 2006. Ear-tag numbers and transmitter frequencies enabled us to identify individuals during each of the counting sessions. We used resights generated by self-triggered camera traps as recaptures. Program Noremark provided Minta-Mangel and Bowden's estimators to assess the size of the marked population. The minimum numbers of wild boars belonging to the unmarked population (juveniles and/ or piglets) were added to the respective estimates to assess total population size. Over the 3 years, both estimators showed a stable population with a slight diminishing tendency. We used mean home range size determined by telemetry to assess the sampled areas and densities. Mean wild boar population densities calculated were 10.6 individuals/km 2 ±0.8 standard deviation (SD) and 10.0 ind/km 2 ± 0.6 SD with both estimators, respectively, and are among the highest reported from Western Europe. Because of the low proportion of marked animals and, to a lesser extent, of technical failures, our estimates showed poor precision, although they displayed similar population trends compared to the culling bag statistics. Reported densities were consistent with the ecological conditions of the study area.

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“…This method also assumes equal sighting probabilities and that no animal is observed or counted twice during any given survey occasion. A detailed discussion by Neal et al (1993) examines the robustness of JHE when various assumptions are not met. Bowden's estimator allows for heterogeneity in animal sighting probability and a geographically "closed" study area.…”

Section: 3mentioning

confidence: 99%

Investigation of anatomical anomalies in Hanford Site mule deer

Tiller¹,

Cadwell²,

Poston³

1997

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Portions of this document may be illegible in electronic image produck Images are produced from the best available original document. Executive SummaryRocky Mountain mule deer (Odocoileus hemionus hemionus), common residents of the Hanford Site, are an important part of the shrub-steppe ecosystem as well as being valued for aesthetics and hunting. Because mule deer have been protected from hunting on the Site for 50 years, the herd has developed unique population characteristics, including a large number of old animals and males with either large or atypically developed antlers, in contrast to other herds in the semi-arid regions of the Northwest.Hanford Site mule deer have been studied since 1991 because of the herd's unique nature and high degree of public interest. A special study of the mule deer herd was initiated in 1993 after observations were made of a relatively large number of male deer with atypical, velvet-covered antlers. This report specifically describes our analyses of adult male deer found on the Site with atypical antlers. The report includes estimates of population densities and composition; home ranges, habitat uses, and dietary habits; natural and human-induced causes of mortality; and the herd's overall health and reproductive status.Examinations of adult male deer exhibiting unusually shaped, velvet-covered antlers were found to have permanently infertile, atrophied (shrunken as opposed to incompletely developed) testicles. The frequency of affected deer observed on Hanford was highly correlated to the frequency of older-aged animals found onsite and was difficult to compare with other more heavily hunted populations. Morphologic, physiologic, and clinical and pathological results showed essentially normal findings, but indicated the causative agent(s) act directly on testicular tissues. Figure S.1 shows a logistical flow diagram for potential causative factors responsible for deer exhibiting unusuaIly shaped, velvet-covered antlers. Radiation, natural aging, infectious agents, and genetic factors were ruled out as primary potential causes. Other factors ruled out as likely causative agents that could warrant further field investigations were thermal stress, nutritional stress, plant estrogens, heavy metals, and herbicides/ pesticides/insectides (Hanford and/or adjacent agricultural areas). Essentially no data were gathered to examine plant or fungal toxins, which could be causative agents.Population-level results indicated that the Hanford Site herd contained a relatively large proportion of male deer, primarily as a result of the lack of hunting pressure and mild winters. Fawn production on Hanford was low. Deer were most abundant along the Columbia River (approximately 330 animals) and on the western portions of the FitznerEberhardt Arid Lands Ecology (ALE) Reserve and were lowest on the 200 Area plateau to the southern border and the eastern portions of ALE. Deer diets and movements indicated a high dependency on riverine habitat, sagebrush, and the sand dunes habitat. The data also sh...

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Evaluation of Mark-Resight Model Assumptions for Estimating Mountain Sheep Numbers

Cited by 78 publications

References 13 publications

Using temporary dye marks to estimate ungulate population abundance in southwest Yukon, Canada

Using temporary dye marks to estimate ungulate population abundance in southwest Yukon, Canada

Estimating wild boar (Sus scrofa) abundance and density using capture–resights in Canton of Geneva, Switzerland

Investigation of anatomical anomalies in Hanford Site mule deer

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