Stapleton S.,University of Minnesota |
Atkinson S.,Environment Canada |
Hedman D.,Manitoba Conservation |
Garshelis D.,University of Minnesota
Biological Conservation | Year: 2014
Capture-based studies of the Western Hudson Bay (WH) polar bear population in Canada have reported declines in abundance, survival, and body condition, but these findings are inconsistent with the perceptions of local people. To address this uncertainty about current status, we conducted a comprehensive aerial survey of this population during August, 2011, when the region was ice-free and bears were on shore. We flew a combination of overland transects oriented perpendicular to the coastline, coastal transects parallel to shore, and transects across small islands. We used distance sampling and sight-resight protocols to estimate abundance. Bears were concentrated along the coast in central and southern Manitoba and Ontario portions of the population, although sightings >10. km inland were not uncommon in central Manitoba. We analyzed 2 combinations of data and derived an abundance estimate of 1030 bears (95% CI: ~754-1406). This figure is similar to a 2004 mark-recapture estimate but higher than projections indicating declining abundance since then. Our results suggest that mark-recapture estimates may have been negatively biased due to limited spatial sampling. We observed large numbers of bears summering in southeastern WH, an area not regularly sampled by mark-recapture. Consequently, previous mark-recapture estimates are not directly comparable to our aerial survey of the entire population. Whereas our results do not necessarily contradict the reported declines in this population, we believe that improvements are needed in monitoring, and methodological limitations and inconsistencies must be resolved to accurately assess status and the impacts of climate change. © 2014 Elsevier Ltd.
Bond-Lamberty B.,Pacific Northwest National Laboratory |
Rocha A.V.,University of Notre Dame |
Calvin K.,Pacific Northwest National Laboratory |
Holmes B.,Manitoba Conservation |
And 2 more authors.
Global Change Biology | Year: 2014
Most North American forests are at some stage of post-disturbance regrowth, subject to a changing climate, and exhibit growth and mortality patterns that may not be closely coupled to annual environmental conditions. Distinguishing the possibly interacting effects of these processes is necessary to put short-term studies in a longer term context, and particularly important for the carbon-dense, fire-prone boreal forest. The goals of this study were to combine dendrochronological sampling, inventory records, and machine-learning algorithms to understand how tree growth and death have changed at one highly studied site (Northern Old Black Spruce, NOBS) in the central Canadian boreal forest. Over the 1999-2012 inventory period, mean tree diameter increased even as stand density and basal area declined significantly. Tree mortality averaged 1.4 ± 0.6% yr-1, with most mortality occurring in medium-sized trees; new recruitment was minimal. There have been at least two, and probably three, significant influxes of new trees since stand initiation, but none in recent decades. A combined tree ring chronology constructed from sampling in 2001, 2004, and 2012 showed several periods of extreme growth depression, with increased mortality lagging depressed growth by ~5 years. Higher minimum and maximum air temperatures exerted a negative influence on tree growth, while precipitation and climate moisture index had a positive effect; both current- and previous-year data exerted significant effects. Models based on these variables explained 23-44% of the ring-width variability. We suggest that past climate extremes led to significant mortality still visible in the current forest structure, with decadal dynamics superimposed on slower patterns of fire and succession. These results have significant implications for our understanding of previous work at NOBS, the carbon sequestration capability of old-growth stands in a disturbance-prone landscape, and the sustainable management of regional forests in a changing climate. © 2013 John Wiley & Sons Ltd.
Rosatte R.,Ontario Ministry of Natural Resources |
Ryckman M.,Manitoba Conservation |
Proceviat S.,Summit Environmental Consultants |
Bruce L.,OMNR |
And 2 more authors.
Journal of Wildlife Rehabilitation | Year: 2010
During 2004 to 2007, twenty rehabilitated raccoons were fitted with radio collars and released within 1 km of their acquisition location in southern Ontario, Canada, to study their movements and survival. Data were used from 13 of those animals. Mean home range for male and female raccoons fitted with VHF collars was 2.4 and 1.0 km 2. Mean and maximum linear distance from the release site for rehabilitated raccoons was a mean of 1 and 2 km, respectively, and the movement rate of male and female GPS-collared raccoons was 90 and 24 m/hr, respectively. Rehabilitated raccoons appeared to use available habitat randomly, with no single habitat being used more or less than expected. Survival of rehabilitated raccoons during the study period was 0.384, with mean survival time for rehabilitated raccoons being 484 ± 83 days. Data suggest that raccoon survival is a function of time and is not affected by rehabilitation status. We suggest that rehabilitated raccoons be released in the general area in which they were acquired, in order to minimize movements and the transmission and spread of infectious diseases and parasites, as well as to minimize the impact on resident animals. © 2010 International Wildlife Rehabilitation Council.
Hettinga P.N.,University of Manitoba |
Arnason A.N.,University of Manitoba |
Manseau M.,University of Manitoba |
Manseau M.,Western and Northern Service Center |
And 3 more authors.
Journal of Wildlife Management | Year: 2012
A critical step in recovery efforts for endangered and threatened species is the monitoring of population demographic parameters. As part of these efforts, we evaluated the use of fecal-DNA based capture-recapture methods to estimate population sizes and population rate of change for the North Interlake woodland caribou herd (Rangifer tarandus caribou), Manitoba, Canada. This herd is part of the boreal population of woodland caribou, listed as threatened under the federal Species at Risk Act (2003) and the provincial Manitoba Endangered Species Act (2006). Between 2004 and 2009 (9 surveys), we collected 1,080 fecal samples and identified 180 unique genotypes (102 females and 78 males). We used a robust design survey plan with 2 surveys in most years and analysed the data with Program MARK to estimate encounter rates (p), apparent survival rates (φ), rates of population change (λ), and population sizes (N). We estimated these demographic parameters for males and females and for 2 genetic clusters within the North Interlake. The population size estimates were larger for the Lower than the Upper North Interlake area and the proportion of males was lower in the Lower (33%) than the Upper North Interlake (49%). Population rate of change for the entire North Interlake area (2005-2009) using the robust design Pradel model was significantly <1.0 (λ = 0.90, 95% CI: 0.82-0.99) and varied between sex and area with the highest being for males in Lower North Interlake (λ = 0.98, 95% CI: 0.83-1.13) and the lowest being for females in Upper North Interlake (λ = 0.83, 95% CI: 0.69-0.97). The additivity of λ between sex and area is supported on the log scale and translates into males having a λ that is 0.09 greater than females and independent of sex, Lower North Interlake having a λ that is 0.06 greater than Upper North Interlake. Population estimates paralleled these declining trends, which correspond to trends observed in other fragmented populations of woodland caribou along the southern part of their range. The results of this study clearly demonstrate the applicability and success of non-invasive genetic sampling in monitoring populations of woodland caribou. © 2012 The Wildlife Society.
Westwood A.R.,University of Winnipeg |
Conciatori F.,University of Winnipeg |
Tardif J.C.,University of Winnipeg |
Knowles K.,Manitoba Conservation
Forest Ecology and Management | Year: 2012
Armillaria spp. are a complex of fungal pathogens affecting populations of trees worldwide, including upland black spruce (Picea mariana (Mill.) B.S.P.). In central Canada, upland black spruce stands are severely infected with Armillaria root disease, which can kill trees across wide areas. In 2007-2008, infected dead and asymptomatic living trees in 12 infection centers were sampled in each of two regions for growth and mortality analyzes. In 2009, a subset of 10 infected dead and 10 asymptomatic living trees from two sites per region were selected for stem analysis. Dendroecological techniques were used to examine mortality patterns and growth changes prior to mortality. The onset of mortality in affected stands occurred quasi-synchronously across the sampling regions, though differences existed among individual sites within each region. Mortality in all black spruce stands occurred at an average of 96-99. years. Testing of incremental growth ratios indicated that infected trees experienced a sustained decline in basal area and volume increment 5-15. years prior to death, as compared to asymptomatic trees. This significant decline in growth was expressed in overall tree productivity. Comparing logistic regression curves of cumulative basal area, height, and volume growth revealed significant differences between asymptomatic and infected trees, indicating that the infected trees grew more quickly at a younger age than asymptomatic trees. It is speculated that their increased vigor and larger root systems may have predisposed these trees for infection as more root area was available for fungal contact. In upland black spruce forests, Armillaria root disease is accelerating forest succession by breaking up the even-aged post-fire cohort and contributing to the presence of dead wood on the forest floor. © 2011 Elsevier B.V.
Rosatte R.,Ontario Ministry of Natural Resources |
Ryckman M.,Manitoba Conservation |
Ing K.,University of Toronto |
Proceviat S.,Summit Environmental Consultants Ltd. |
And 4 more authors.
Journal of Mammalogy | Year: 2010
During 19942007 a total of 156,416 raccoons was live-captured in Ontario, Canada, as part of markrecapture studies to estimate raccoon density during rabies-control operations. Mean density in southern Ontario ranged between 3.4 and 13.6 raccoons/km2 when density in northern Ontario was <1.5 raccoons/km2. Raccoon density also was significantly higher in mixed cropland and deciduous habitats than in large tracts of deciduous forest in southern Ontario. Raccoons generally travelled <5 km between years during 19941997 markrecapture movement studies in Niagara; however, movements as great as 45 km and among-year differences in movements were observed. Raccoons in rural habitats also moved more extensively than those in urban areas in 1994. Mean home range (minimum convex polygon) for raccoons in eastern Ontario during 20032007 was 3.9 km2 for very-high-frequencycollared raccoons and 3.4 km2 for global positioning systemcollared raccoons. Mean movement from the release site by collared raccoons over the study period was 1.5 km with the longest movement being 10.3 km. No single habitat was used more or less by collared raccoons than expected. Survival of radiocollared raccoons over the course of the study was 0.62 with survival of raccoons initially captured and released as juveniles and adults being an average of 964 and 786 days. Knowledge of the ecology of raccoons should be used during planning for disease management, and was critical to evaluating the success of rabies-control programs in Ontario, Canada. © 2010 American Society of Mammalogists.
News Article | February 29, 2016
Polar bear encounters with humans are on the rise, as suggested by documents from the Manitoba government in Canada. In fact, encounters on the Hudson Bay shores may have reached a record high. As a result, more polar bears are ending up in specialized lockups in Churchill. In 2013, there were 229 documented polar bear cases in Churchill. The numbers jumped to 351 cases in 2015, Manitoba Conservation regional wildlife manager Daryll Hedman said it was a high number for occurrences. Commonly known as the "polar bear jail," the holding facility is where polar bears are locked and tranquilized before its re-entry into the wild. In 2013, there were 36 bears in custody. In 2015, the inmate population jumped to 65. Patrol officers from the Manitoba Conservation increased their activities already but Hedman and other specialists said climate change has a lot to do with the increased polar bear encounters. Two-thirds of the entire polar bear population call Canada its home. Unfortunately, due to the effects of climate change, the polar bear population in Hudson Bay could be extinct in the next several decades. Hunting during the winter months is important for the polar bears. They use this time to stock up on fatty seal meat to help them make it through the summer months when they suffer food scarcity on land. Recently, there has been delay in the yearly freezing in the Arctic waters. Additionally, the ice melt faster during spring. These shrink the polar bears' window to stock up on the seal meat they need for fat build-up. Since fatty meat is scarce in dry land, hungry polar bears on land tend to venture in human towns for food. Normally, polar bear encounters happen around late August. Hedman said that lately, polar bear encounters are documented as early as the first of July. "What's the tipping point? What's the threshold that they can go without food? When they're on land, they're not eating." added Hedman. It's a question of how long these polar bears can go on without hunting seals on the sea ice. University of Alberta's polar bear expert Andrew Derocher said that as polar bear spend more time on dry land without food, the chances of venture into populated areas increases. "Hungry bears are always going to be a problem. All projections are that they will increase their on-land time," said Derocher.