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Publications (74)
One of the challenges in conservation is determining patterns and responses in population density and distribution as it relates to habitat and changes in anthropogenic activities. We applied spatially explicit capture recapture (SECR) methods, combined with density surface modelling from five grizzly bear (Ursus arctos) management areas (BMAs) in...
1. Spatially explicit capture–recapture methods use data from the detection of marked animals at known points in space to estimate animal population density without bias from edge effects. Detection is by means of stationary devices such as traps, automatic cameras or DNA hair snags. Data collection is often expensive, and it is not obvious how to...
The zone of influence (ZOI) is the area in the vicinity of industrial development where avoidance by caribou Rangifer tarandus or other wildlife species is observed. Here we examine ZOI around two diamond mines in the Northwest Territories (NWT), Canada from 1998 to 2017. In this paper, we further develop segmented/piecewise regression methods to a...
Populations of bears in Asia are vulnerable to extinction and effective monitoring is critical to measure and direct conservation efforts. Population abundance (local density) or growth (λ) are the most sensitive metrics to change. We discuss and recommend implementing spatially explicit capture-recapture (SCR), the current gold standard for densit...
A challenge for management of wildlife species is the assessment of the effect of roads on migration. We developed models to estimate the spatial (zone of influence (ZOI)) and temporal (delays in migration) effects of roads, and test whether road closures reduced delays in migration. We analyzed collar (2011–2019) and road survey data from two barr...
American black (Ursus americanus) and grizzly bears (U. arctos) are sympatric throughout much of the grizzly bear's range, but information on how they share the landscape is lacking because distribution usually is not estimated simultaneously for both species. Here we analyze DNA data from noninvasively collected hair (using hair snags and rub tree...
The influence of bottom-up food resources and top-down mortality risk underlies the demographic trajectory of wildlife populations. For species of conservation concern, understanding the factors driving population dynamics is crucial to effective management and, ultimately, conservation. In southeastern British Columbia, Canada, populations of the...
Designing a population monitoring program for Asian bears presents challenges associated with their low densities and detectability, generally large home ranges, and logistical or resource constraints. The use of an occupancy-based method to monitor bear populations can be appropriate under certain conditions given the mechanistic relationship betw...
Mining activities in Canada’s pristine Arctic (e.g., driving on unpacked roads, blasts, rock grinding, diesel combustion, and garbage incineration) could add local sources of airborne fine particulate matter with a diameter of < 2.5 μm (PM2.5) to their surrounding area. The increase in PM2.5 above the background level around a mine represents a pot...
Wildlife managers conduct population inventories to monitor species, particularly those at-risk. Although costly and time consuming, grid-based DNA hair-snag sampling has been the standard protocol for grizzly bear inventories in North America, while opportunistic fecal DNA sampling is more commonly used in Europe. Our aim is to determine if low-co...
Wildlife managers conduct population inventories to monitor species, particularly those at-risk. Although costly and time consuming, grid-based DNA hair-snag sampling has been the standard protocol for grizzly bear inventories in North America, while opportunistic fecal DNA sampling is more commonly used in Europe. Our aim is to determine if low-co...
Trends in population abundance can be challenging to quantify during range expansion and contraction, when there is spatial variation in trend, or the conservation area is large. We used genetic detection data from natural bear rubbing sites and spatial capture-recapture (SCR) modeling to estimate local density and population growth rates in a griz...
This report describes the results of a calving ground photo survey of the Bluenose-East caribou herd conducted in June of 2018 near Kugluktuk, Nunavut (NU). The objective was to estimate abundance of breeding females and overall herd size that could be compared to results of previous calving ground surveys done in 2010, 2013 and 2015.
We used col...
Post-calving surveys to estimate herd size of barren-ground caribou (Rangifer tarandus groenlandicus, R. t. granti, and R. t. caribou) have been used for caribou herds in Alaska, Yukon, Northwest Territories, Nunavut, and Québec/Labrador. The main field procedure uses relocation of collared caribou to locate aggregated groups of hundreds or thousan...
Although combining genetic and endocrine data from non-invasively collected hair samples has potential to improve the conservation of threatened mammals, few studies have evaluated this opportunity. In this study, we determined if steroid hormone (testosterone, progesterone, estradiol and cortisol) concentration profiles in 169 hair samples collect...
Recognizing the potential value of steroid hormone measurements to augment non-invasive genetic sampling, we developed procedures based on enzyme-linked immunoassays to quantify reproductive steroid hormone concentrations in brown bear (Ursus arctos) hair. Then, using 94 hair samples collected from eight captive adult bears over a 2-year period, we...
Two photographic survey methods have long been used in Canada's Northwest Territories and Nunavut to estimate herd size in migratory barren-ground caribou herds (Rangifer tarandus groenlandicus). The calving photo-survey provides an estimate of the abundance of breeding females on the calving grounds in June and can be extrapolated to an estimate o...
This study explores how dust from the Ekati Diamond Mine potentially affects the availability and quality of forage on the seasonal range of the Bathurst caribou herd. Understanding the effects of dust as a source of disturbance is important because the Bathurst caribou population has declined by 93% since the middle 1980s and there are reports tha...
This report details the calving ground photo survey of the Bluenose-East caribou herd conducted during June of 2015 in Nunavut (NU), near Kugluktuk, NU. The main objective was to obtain an estimate of breeding females that could be compared to estimates from previous calving ground surveys in 2010 and 2013. Consistent with previous calving ground p...
A novel antibody-based protein microarray was developed that simultaneously determines expression of 31 stress-associated proteins in skin samples collected from free-ranging grizzly bears (Ursus arctos) in Alberta, Canada. The microarray determines proteins belonging to four broad functional categories associated with stress physiology: hypothalam...
The Beverly herd was one of the first large migratory herds of barren-ground caribou (Rangifer tarandus groenlandicus) defined in northern Canada on the basis of annual return of breeding females to traditional calving grounds near Beverly Lake in Nunavut. In 1994, herd size was estimated at 276 000 ± 106 600 (SE) adult caribou, but monitoring was...
Brown bears (Ursus arctos) inhabit much of the northern hemisphere, including
portions of North America, Europe, and Asia. Whereas northern populations generally are
healthy, their distribution becomes fragmented and conservation status more tenuous in their
southern range. Many fragmented populations across southern Asia are poorly understood,
and...
The conservation status of the 2 threatened grizzly bear (Ursus arctos) populations in the Cabinet-Yaak Ecosystem (CYE) of northern Montana and Idaho had remained unchanged since designation in 1975; however, the current demographic status of these populations was uncertain. No rigorous data on population density and distribution or analysis of rec...
In late February and March 2014, we estimated the abundance of barren-ground caribou on Baffin Island and ancillary islands, and northern Melville Peninsula using double observer pair and distance sampling methods. The survey was enhanced through the guidance of local knowledge and inclusion of Inuit Qaujimjatuqangit (IQ) from ten Baffin Island com...
Assessing grizzly bears' (Ursus arctos) abundance in the Arctic has been challenging because of the large scale of their movements and the remoteness of field locations. We modified a post sampling method used for wolverines (Gulo gulo) to allow collection of hair samples from grizzly bears in the Canadian tundra. We deployed 1 post/cell in a sampl...
Accurate and precise estimates of population size are critical for effective management but can be particularly difficult to achieve for small populations of large carnivores. We approached this challenge by integrating multiple noninvasive data sources into a DNA-based mark–recapture framework to estimate the abundance of the small and endangered...
One of the principal factors that have reduced grizzly bear populations has been the creation of human access into grizzly bear habitat by roads built for resource extraction. Past studies have documented mortality and distributional changes of bears relative to roads but none have attempted to estimate the direct demographic impact of roads in ter...
Guided by deeply held cultural values, First Nations in Canada are rapidly regaining legal authority to manage natural resources. We present a research collaboration among academics, tribal government, provincial and federal government, resource managers, conservation practitioners, and community leaders supporting First Nation resource authority a...
We used the calving ground photographic survey technique to estimate abundance and distribution of breeding females in the Bathurst herd of barren-ground caribou (Rangifer tarandus groenlandicus) in June 2009. In late May 2009, we started monitoring movements and locations of satellite collared Bathurst cows (n=11). We used Tahera Mine, located by...
Individual body growth is controlled in large part by the spatial and temporal heterogeneity of, and competition for, resources. Grizzly bears (Ursus arctos L.) are an excellent species for studying the effects of resource heterogeneity and maternal effects (i.e. silver spoon) on life history traits such as body size because their habitats are high...
One of the principal goals of wildlife research and management is to understand and predict relationships be-tween habitat quality, health of individuals and their ability to survive. Infrequent sampling, non-random loss of individuals due to mortality and variation in capture susceptibility create potential biases with conventional analysis method...
Wildlife species may respond to industrial development with changes in distribution. However, discerning a response to development from differences in habitat selection is challenging. Since the early 1990s, migratory tundra Bathurst caribou Rangifer tarandus groenlandicus in the Canadian Arctic have been exposed to the construction and operation o...
When dealing with small populations of elusive species, capture–recapture methods suffer from sampling and analytical limitations, making abundance assessment particularly challenging. We present an empirical and theoretical evaluation of multiple data source sampling as a flexible and effective way to improve the performance of capture–recapture m...
Wildlife species may respond to industrial development with changes in distribution. However, discerning a response to development from differences in habitat selection is challenging. Since the early 1990s, migratory tundra Bathurst caribou Rangifer tarandus groenlandicus in the Canadian Arctic have been exposed to the construction and operation o...
The Bathurst herd of barren-ground caribou (Rangifer tarandus groenlandicus) in the Canadian central arctic declined from an estimated 203,800 to 16,400 breeding females from 1986 to 2009, with the most rapid decline from 2006 to 2009. A key research and management question was whether the decline was mainly due to decreases in productivity alone o...
We used two island populations of snowshoe hares (Lepus americanus) in the Kluane Lake area of the Yukon Territory of Canada to evaluate capture – recapture estimators. These islands were intensively sampled, allowing us to enumerate the actual population size. Population size estimates were calculated using the programs CAPTURE and JOLLY, and esti...
ABSTRACT Grizzly bears (brown bears; Ursus arctos) are imperiled in the southern extent of their range worldwide. The threatened population in northwestern Montana, USA, has been managed for recovery since 1975; yet, no rigorous data were available to monitor program success. We used data from a large noninvasive genetic sampling effort conducted...
We present the first rigorous estimate of grizzly bear (Ursus arctos) population density and distribution in and around Glacier National Park (GNP), Montana, USA. We used genetic analysis to identify individual bears from hair samples collected via 2 concurrent sampling methods: 1) systematically distributed, baited, barbed-wire hair traps and 2) u...
Large carnivores potentially change their behavior following physical capture, becoming less responsive to the attractants that resulted in their capture, which can bias population estimates where the change in behavior is not appropriately modeled. We applied occupancy models to efficiently estimate and compare detection probabilities of previousl...
Grizzly bears (Ursus arctos) occur across British Columbia and in Alberta in mostly forested, mountainous, and boreal ecosystems. These dense forests make sighting bears from aircraft uncommon and aerial census impractical. Since 1995, we have used genetic sampling using DNA from bear hair collected with barbed wire hair traps to explore a suite of...
Resource extraction activities in Alberta, Canada, have produced a large increase in the number of roads in grizzly bear (Ursus arctos) habitat. High road densities have been associated with high grizzly bear mortality rates in some areas. We used GPS data from grizzly bears in west-central Alberta, Canada, 1999–2005 to examine (1) frequencies at w...
It is often difficult to determine optimal sampling design for non-invasive genetic sampling, especially when dealing with
rare or elusive species depleted of genetic diversity. To address this problem, we ran a hair-snag pilot study on the remnant
Apennine brown bear population. We used occupancy models to estimate the performance of an improved f...
Over a 3-year period, we assessed 2 sampling designs for estimating grizzly bear (Ursus arctos) population size using DNA capture–mark–recapture methods on a population of bears that included radiomarked individuals. We compared a large-scale design (with 8 × 8-km grid cells and sites moved for 4 sessions) and a small-scale design (5 × 5-km grid ce...
We used Doncaster's test to differentiate home range overlap in range use from mutual attraction in grizzly bears (Ursus arctos) based on global positioning system (GPS) telemetry data. From a sample of 61 collared bears, 404 pairs of GPS locations placed 2 or more bears ≤500 m from each other at about the same time (within 3 hr). From these 404 p...
This report presents estimates of adult survival, cub survival, and reproductive rate for grizzly bears collared as part of the Foothills Research Institute's Grizzly Bear Program (FRIGBP) for the period 1999-2009, along the eastern slopes of Alberta. The estimates from this study are compared to estimates from longer-term studies to allow a relati...
Although the brown bear (Ursus arctos) Population in Abruzzo (central Apennines, Italy) suffered high mortality during the past 30 years and is potentially at high risk of extinction. no formal estimate of its abundance has been attempted. In 2004. the Italian Forest Service and Abruzzo National Park applied DNA-based techniques to hair-snag sample...
The need to capture wild animals for conservation, research, and management is well justified, but long-term effects of capture and handling remain unclear. We analyzed standard types of data collected from 127 grizzly bears (Ursus arctos) captured 239 times in western Alberta, Canada, 1999-2005, and 213 American black bears (U. americanus) capture...
A fundamental challenge to estimating population size with mark-recapture methods is heterogeneous capture probabilities and subsequent bias of population estimates. Confronting this problem usually requires substantial sampling effort that can be difficult to achieve for some species, such as carnivores. We developed a methodology that uses two da...
Paetkau, D. 2007: Estimation of population size for wolverines Gulo gulo at Daring Lake, Northwest Territories, using DNA based mark-recapture methods. -Wildl. Biol. 13 (Suppl. 2): 38-51. This paper presents the results of the first substantive DNA mark-recap-ture sampling effort for wolverines Gulo gulo using hair-snag sampling. In the spring of 2...
Despite the widespread use of DNA mark–recapture for estimation of grizzly bear (Ursus arctos) population size, there have been no designed experiments of DNA sampling strategies. We designed a large-scale study (8,820 km 2) in the foothills of Alberta, Canada, to test sampling strategies associated with the hair snag DNA method. The main sampling...
We studied northern flying squirrel (Glaucomys sabrinus) demography in the eastern Washington Cascade Range to test hypotheses about regional and local abundance patterns and to inform managers of the possible effects of fire and fuels management on flying squirrels. We quantified habitat characteristics and squirrel density, population trends, and...
We used DNA sampling and mark-recapture modeling to estimate population trend(s), population size, and the demographic response of a coastal British Columbia grizzly bear population (Ursus arctos L., 1758) to low salmon escapement levels from 1998 to 2002. We contrasted the demography of three sampling areas in response to temporal and spatial vari...
One of the challenges in estimating grizzly bear (Ursus arctos) population size using DNA methods is heterogeneity of capture probabilities. This study developed general tools to explore heterogeneity variation using data from a DNA mark-recapture project in which a proportion of the bear population had GPS collars. The Huggins closed population ma...
1. The objectives of the aerial survey portion of the caribou monitoring program should be
revised with an emphasis on documenting the distribution and composition of caribou herds
within the regional study area.
2. The study area should be expanded up to a 30-km buffer around mine development to
incorporate areas of low probability of effect of mi...