scholarly journals Changes in landscape composition influence the decline of a threatened woodland caribou population

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
B McLellan ◽  
R Serrouya ◽  
C Apps
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Apparent Competition ◽  
Timber Harvesting ◽  
Conservation Strategies ◽  
Home Ranges ◽  
Vital Rates ◽  
Population Declines ◽  
Woodland Caribou ◽  
Habitat Alterations

Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator-prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0.67-0.93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change. © 2007 The Authors. Journal compilation © 2007 British Ecological Society.

scholarly journals Changes in landscape composition influence the decline of a threatened woodland caribou population

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
B McLellan ◽  
R Serrouya ◽  
C Apps
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Apparent Competition ◽  
Timber Harvesting ◽  
Conservation Strategies ◽  
Home Ranges ◽  
Vital Rates ◽  
Population Declines ◽  
Woodland Caribou ◽  
Habitat Alterations

Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator-prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0.67-0.93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change. © 2007 The Authors. Journal compilation © 2007 British Ecological Society.

scholarly journals Predator management and species at risk in Alberta

2016 ◽  
Author(s):  
Dave Hervieux
Keyword(s):  
Current Knowledge ◽  
Apparent Competition ◽  
Provincial Government ◽  
Management Approach ◽  
Population Declines ◽  
Woodland Caribou ◽  
Management Actions ◽  
Habitat Recovery ◽  
Predator Management ◽  
Anthropogenic Habitat

Alberta has employed lethal techniques to reduce predator populations in several wildlife-management situations, particularly in attempts to achieve goals and objectives for threatened or endangered species. Annual wolf populations reductions within and adjacent to woodland caribou population ranges in West Central Alberta are a notable example of this management approach. Almost all woodland caribou populations in Alberta are exhibiting ongoing population declines, with some populations declining at rapid rates. Current knowledge indicates that these declines are from apparent competition due to anthropogenic habitat changes, with resulting unsustainably high levels of wolf predation on woodland caribou populations. Delivery of annual wolf population reductions for two woodland caribou populations has resulted in stable or slightly increasing caribou population growth; in the absence of the wolf program at least one of the caribou populations would now be extirpated. The delivery of lethal wolf management for woodland caribou conservation and recovery in Alberta is enabled by a variety of provincial government approved management plans and policies. It is fully recognized that predator management for woodland caribou recovery must be predicated on management approaches and actions to improve caribou habitat conservation and recovery and thereby address the ultimate factors influencing apparent competition and unsustainably high levels of predation. Considerable effort is now being devoted to planning, policy revisions, regulatory adjustments, and management actions to address fundamental considerations related to caribou habitat. Progress on woodland caribou habitat will have little relevance; however, if the resident caribou population becomes extirpated before sufficient habitat recovery is achieved. Effective reductions in predation rates are needed immediately.

scholarly journals Preliminary assessment of habitat characteristics of woodland caribou calving areas in the Claybelt region of Québec and Ontario, Canada

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 247 ◽  
Author(s):  
Émilie Lantin ◽  
Pierre Drapeau ◽  
Marcel Paré ◽  
Yves Bergeron
Keyword(s):  
Large Scale ◽  
Rangifer Tarandus ◽  
Forest Cover ◽  
Black Spruce ◽  
Spatial Scales ◽  
Habitat Characteristics ◽  
Percent Cover ◽  
Woodland Caribou ◽  
Vegetation Characteristics ◽  
Forest Cover Types

Woodland caribou (Rangifer tarandus caribou) require a diversity of forested habitats over large areas and may thus be particularly affected by the large-scale changes in the composition and age-class distribution of forest landscapes induced by the northern expansion of forest management. In this study we examine habitat characteristics associated to the use of calving areas by woodland caribou females and calves at different spatial scales. Thirty females were captured and collared with Argos satellite transmitters that allowed to locate 14 calving areas. Field surveys were conducted at each of these areas to measure the landscape composition of forest cover types and local vegetation characteristics that are used for both forage conditions and protection cover. At the scale of the calving area, univariate comparisons of the amount of forest cover types between sites with and without calves showed that the presence of calves was associated to mature black spruce forest with a high percent cover of terrestrial lichens. Within calving grounds, univariate comparisons showed that vegetation features like ericaceans and terrestrial lichens, that are important food resources for lactating females, were more abundant in calving areas where females were seen with a calf in mid-July than in areas where females were seen alone. The protection of the vegetation cover against predators was however similar between calving areas with or with¬out a calf. Logistic regression results also indicated that vegetation characteristics associated to forage conditions were positively associated to calf presence on calving grounds. Our results suggest that foraging conditions should be given more attention in analyses on habitat requirements of woodland caribou.

scholarly journals Incorporating Archaeological Resources in Landscape-Level Planning and Management

2016 ◽  
Vol 4 (2) ◽  
pp. 118-131 ◽  
Author(s):  
William H. Doelle ◽  
Pat Barker ◽  
David Cushman ◽  
Michael Heilen ◽  
Cynthia Herhahn ◽  
...  
Keyword(s):  
Scale Development ◽  
Large Scale ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Mitigation Measures ◽  
Conservation Strategies ◽  
Archaeological Record ◽  
Key Drivers ◽  
Multiple Resource ◽  
Landscape Level

AbstractThe increasing importance of landscape-scale research and preservation goals within the archaeological profession coincides with expanded threats to the archaeological record through massive energy exploration and infrastructure projects and through the cumulative effects of smaller-scale development. It is further stimulated by the recognition that conservation strategies that span multiple resource classes and disciplines are best formulated at multiple and larger spatial scales. These are key drivers behind efforts to improve the ways that archaeological resources are considered in the context of development-related planning and implementation, including mitigation measures. In a prominent example, recent department-level direction from the Secretary of the Interior calls specifically for landscape-level planning as a critical component of responses to both large-scale development and climate change. This article reviews three current approaches to landscape-level planning in archaeology and calls for increased commitment to advancing their development and effectiveness.

scholarly journals Exploration in Mapping Kernel-Based Home Range Models from Remote Sensing Imagery with Conditional Adversarial Networks

2018 ◽  
Vol 10 (11) ◽  
pp. 1722
Author(s):  
Ruobing Zheng ◽  
Guoqiang Wu ◽  
Chao Yan ◽  
Renyu Zhang ◽  
Ze Luo ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Home Range ◽  
Large Scale ◽  
Qinghai Lake ◽  
Conservation Strategies ◽  
Home Ranges ◽  
Lake Area ◽  
Range Analysis ◽  
Remote Sensing Imagery ◽  
Adversarial Network

Kernel-based home range models are widely-used to estimate animal habitats and develop conservation strategies. They provide a probabilistic measure of animal space use instead of assuming the uniform utilization within an outside boundary. However, this type of models estimates the home ranges from animal relocations, and the inadequate locational data often prevents scientists from applying them in long-term and large-scale research. In this paper, we propose an end-to-end deep learning framework to simulate kernel home range models. We use the conditional adversarial network as a supervised model to learn the home range mapping from time-series remote sensing imagery. Our approach enables scientists to eliminate the persistent dependence on locational data in home range analysis. In experiments, we illustrate our approach by mapping the home ranges of Bar-headed Geese in Qinghai Lake area. The proposed framework outperforms all baselines in both qualitative and quantitative evaluations, achieving visually recognizable results and high mapping accuracy. The experiment also shows that learning the mapping between images is a more effective way to map such complex targets than traditional pixel-based schemes.

Implementing wildfire-based timber harvest guidelines in southeastern Manitoba

2002 ◽  
Vol 78 (5) ◽  
pp. 680-685 ◽  
Author(s):  
James Ehnes ◽  
Vince Keenan
Keyword(s):  
Ecosystem Health ◽  
Large Scale ◽  
Sustainable Forest Management ◽  
Spatial Scales ◽  
Natural Disturbance ◽  
Timber Harvest ◽  
Timber Harvesting ◽  
Landscape Design ◽  
Site Preparation ◽  
Design Guidelines

The Manitoba Model Forest and Tembec Industries (Pine Falls Operations) are operationalizing the overall goal of sustainable forest management: maintain forest ecosystem health while harvesting timber. Timber harvest guidelines intended to approximate the effects of a large wildfire were developed for spatial scales that span from the operating area down to the site. Operating area issues are addressed through landscape design guidelines that locate cutblocks and other activities (e.g., roads) within an operating area. Cut-block guidelines determine how harvesting, site preparation and regeneration are completed. These wildfire-based guidelines are being tested in four large-scale harvest trials in southeastern Manitoba. This paper describes the rationale behind the approach taken, the landscape design and cutblock operating guidelines that were developed, operational experiences from the harvest trials, and some of the challenges that arose. Key words: wildfire, operating guidelines, landscape design, timber harvesting, site preparation, regeneration, natural disturbance emulation, ecosystem processes, ecosystem health, maintaining biodiversity, maintaining ecosystem condition

Moose, caribou, and fire: have we got it right yet?

2019 ◽  
Vol 97 (10) ◽  
pp. 866-879 ◽  
Author(s):  
C.A. DeMars ◽  
R. Serrouya ◽  
M.A. Mumma ◽  
M.P. Gillingham ◽  
R.S. McNay ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Rangifer Tarandus ◽  
Community Dynamics ◽  
Spatial Scales ◽  
Natural Disturbance ◽  
Apparent Competition ◽  
Time Frame ◽  
Population Declines ◽  
Dominant Form ◽  
Demographic Response

Natural disturbance plays a key role in shaping community dynamics. Within Canadian boreal forests, the dominant form of natural disturbance is fire, and its effects are thought to influence the dynamics between moose (Alces alces (Linnaeus, 1758)) and the boreal ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). Boreal caribou are considered “threatened” and population declines are attributed, at least in part, to disturbance-mediated apparent competition (DMAC) with moose. Here, we tested a primary prediction of the DMAC hypothesis: that moose respond positively to burns within and adjacent to the caribou range. We assessed moose selection for ≤25-year-old burns (when selection is predicted to be strongest) at multiple spatial scales and evaluated whether moose density was correlated with the extent of ≤40-year-old burns (a time frame predicted to negatively affect caribou). Against expectation, moose showed avoidance and low use of ≤25-year-old burns at all scales, regardless of burn age, season, and type of land cover burned. These findings mirrored the demographic response, as we found no correlation between ≤40-year-old burns and moose density. By contradicting the prevailing hypothesis linking fires to caribou population declines, our results highlight the need to understand regional variation in disturbance impacts on caribou populations.

scholarly journals Predator management and species at risk in Alberta

2016 ◽  
Author(s):  
Dave Hervieux
Keyword(s):  
Current Knowledge ◽  
Apparent Competition ◽  
Provincial Government ◽  
Management Approach ◽  
Population Declines ◽  
Woodland Caribou ◽  
Management Actions ◽  
Habitat Recovery ◽  
Predator Management ◽  
Anthropogenic Habitat

Alberta has employed lethal techniques to reduce predator populations in several wildlife-management situations, particularly in attempts to achieve goals and objectives for threatened or endangered species. Annual wolf populations reductions within and adjacent to woodland caribou population ranges in West Central Alberta are a notable example of this management approach. Almost all woodland caribou populations in Alberta are exhibiting ongoing population declines, with some populations declining at rapid rates. Current knowledge indicates that these declines are from apparent competition due to anthropogenic habitat changes, with resulting unsustainably high levels of wolf predation on woodland caribou populations. Delivery of annual wolf population reductions for two woodland caribou populations has resulted in stable or slightly increasing caribou population growth; in the absence of the wolf program at least one of the caribou populations would now be extirpated. The delivery of lethal wolf management for woodland caribou conservation and recovery in Alberta is enabled by a variety of provincial government approved management plans and policies. It is fully recognized that predator management for woodland caribou recovery must be predicated on management approaches and actions to improve caribou habitat conservation and recovery and thereby address the ultimate factors influencing apparent competition and unsustainably high levels of predation. Considerable effort is now being devoted to planning, policy revisions, regulatory adjustments, and management actions to address fundamental considerations related to caribou habitat. Progress on woodland caribou habitat will have little relevance; however, if the resident caribou population becomes extirpated before sufficient habitat recovery is achieved. Effective reductions in predation rates are needed immediately.

scholarly journals No evidence of a demographic response to experimental herbicide treatments by the White-crowned Sparrow, an early successional forest songbird

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
James W Rivers ◽  
Jake Verschuyl ◽  
Carl J Schwarz ◽  
Andrew J Kroll ◽  
Matthew G Betts
Keyword(s):  
Pacific Northwest ◽  
Large Scale ◽  
Nest Survival ◽  
Control Measures ◽  
Vital Rates ◽  
Population Declines ◽  
Vegetative Cover ◽  
Vegetation Control ◽  
Herbicide Treatments ◽  
Demographic Response

Abstract Early-successional forest birds, which depend on disturbance events within forested landscapes, have received increased conservation concern because of long-term population declines. Herbicides are often used to control vegetation within early-successional forests, with unknown effects on avian vital rates. We used a large-scale experiment to test how nest and post-fledging survival were influenced by herbicide intensity within managed conifer plantations across 2 breeding seasons. We created a gradient of 4 stand-scale herbicide treatments (light, moderate, and intensive, and no-spray control) and evaluated the reproductive response of the White-crowned Sparrow (Zonotrichia leucophrys), a declining songbird in managed forest landscapes of the Pacific Northwest. Against initial predictions, we found no evidence that either daily nest survival (n > 760 nests across all treatments) or post-fledging survival (n = 70 individuals reared in control and moderate treatments) were influenced by herbicide application intensity. Increased herbicide intensity resulted in an extensive reduction in vegetation cover at both stand and nest-patch scales; in contrast, vegetative cover at nest sites did not differ across herbicide treatments, nor was nest survival related to vegetation concealment measures. As the largest experimental investigation to assess forest herbicide effects on songbird demography, our study indicates that components of sparrow reproductive success were not influenced by experimental vegetation control measures, although additional work on other early-successional species will be useful to evaluate the generalities of our findings.

scholarly journals Effect of heterogeneity in burn severity on Mexican fox squirrels following the return of fire

2013 ◽  
Vol 22 (3) ◽  
pp. 405 ◽  
Author(s):  
Sandra L. Doumas ◽  
John L. Koprowski
Keyword(s):  
Native Species ◽  
Large Scale ◽  
Wildlife Conservation ◽  
Spatial Scales ◽  
Species Conservation ◽  
Burn Severity ◽  
Resource Utilisation ◽  
Home Ranges ◽  
Wildlife Species ◽  
Fox Squirrels

After decades of suppression, fire has returned to many forested areas of the western United States. Understanding responses of wildlife species to fire is essential to native species conservation because contemporary fires may not have the same effects as historical fires. Recent fires in the Chiricahua Mountains of Arizona provided an opportunity to investigate effects of fire heterogeneity on habitat selection of a native wildlife species. We used radiotelemetry to determine home ranges of Mexican fox squirrels (Sciurus nayaritensis chiricahuae) within fire-influenced forests. We then applied resource-utilisation functions to evaluate associations of use intensity within home ranges to heterogeneity of burn severity at two spatial scales. Squirrels used areas with moderate levels of burn heterogeneity at large scale more than areas of low or high heterogeneity. Squirrels used small (<0.5 ha) or narrow (<120 m) severely burnt patches, but incorporated only edges of large patches into home ranges. Use of burnt forests by Mexican fox squirrels demonstrates the complexities of fire’s effects on wildlife. Our results contribute to an understanding of the role and effect of fire in forest ecosystems and implications for wildlife conservation.

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