21 research outputs found
Habitat Use by Breeding Northern Bobwhites in Managed Old-Field Habitats in Mississippi
To better understand the proximate and ultimate cues associated with habitat selection in breeding northern bobwhites (Colinus virginianus), we compared habitat use vs. availability at 2 spatial scales equivalent to Johnson\u27s (1980) 2nd and 3,d order selection. We conducted the study in managed old-field habitats in Mississippi, from 1994 to 1996. We also estimated habitat use by broods with respect to availability, and quantified micro-habitat characteristics (4th order selection) at brood-rearing sites and nesting sites. Breeding bobwhites did not establish home ranges at random or allocate resources among patches in proportion to their availability. Breeding bobwhites, given a mosaic of seasonally manipulated old-field habitats, consistently used burned fields, disked fields, and areas with advanced woody succession to define breeding season home ranges. Bobwhites allocated their time and resources more to woody areas and fields that had received a combination of burning and disking. Broods consistently used burned/disked fields in proportion to availability; consistently avoided row crops and pastures; and generally preferred woody corridors. Vegetation characteristics at nest sites did not differ from random sites located within the same patch of habitat. Characteristics among nest sites were similar, yet successful nests were located in the proximity of more bare ground and less litter cover than unsuccessful nest sites. Brood site habitat characteristics were similar to nest sites; however, woody canopy (44.3%) and visual obstruction readings (59.0cm) at brood sites were significantly greater than nest sites (26.6% and 32.5cm)
Estimating the Total Economic Impact of Black Bear Peeling in Western Oregon Using GIS and REMI
In parts of the Pacific Northwest, black bears emerge from winter dens with depleted fat reserves and feed on mature conifers by stripping bark and consuming sugar-rich sapwood. Peeling by bears affects commercial conifers through direct loss of the tree or degraded log quality at stand harvest. Bears generally peel trees from 15-30 years old in intensively managed forests until preferred foods such as fruits and berries are available, and a single bear can peel several trees per day. Dying trees have a signature red canopy and are detected in annual aerial forest health surveys; however, trees that scar over peeling are not detected by aerial surveys. Previous studies reported results of damage summaries for northwest Oregon from flights, adjusted for bias; however, they offered no estimates of economic impact. Using landowner survey data, another study estimated an annual timber loss to bears at approximately 0.9-$89 million annually, and resulted in an annual loss of between 11 and 1,012 jobs in the state. We will explain our methodology in this study as well as current efforts to improve the accuracy and precision of damage estimates, and ultimately our understanding of the economic impacts of black bear peeling
Seasonal Survival and Cause-Specific Mortality of Northern Bobwhites in Mississippi
Knowledge of northern bobwhite (Colinus virginianus) survival and rates at which specific mortality agents remove individuals from the population is important for implementation of science-based harvest and habitat management regimes. To better understand population response to habitat management, we monitored 194 radio-marked northern bobwhites in managed old-field habitats in eastcentral Mississippi, 1993 to 1996. Bobwhite populations increased during the first 3 years following initiation of disking and burning practices. During the 2nd year of bobwhite habitat management breeding season survival (0.509) was high relative to other southeastern populations. However, breeding season survival declined from the 2nd through the 5th year of management (1993, 0.509; 1994, 0.362; 1995, 0.338; 1996, 0.167; P \u3c 0.001). Declining seasonal survival was attributable to increasing mammalian mortality from 1993 to 1996 (P \u3c 0.01). Avian mortality rates were stochastic and differed among years (P = 0.04), while unknown mortality rates were similar (P = 0.13). Avian mortality evidently operated in a density-dependent fashion, whereas mammalian mortality continued to increase despite declining bobwhite population. Northern bobwhite cause-specific mortality rates among years differed by sex (P \u3c 0.01) and age (P \u3c 0.01). Indices of breeding season relative abundance declined with declining survival. We hypothesize that manipulations (bum, disk, bum/disk) which created habitat that met the seasonal requirements of breeding bobwhites and other early successional prey species, may have resulted in a functional and numerical response of mammalian predators
Evaluation of harassment of migrating double-crested cormorants to limit depredation on selected sport fisheries in Michigan
Diverse management techniques have been used to mitigate conflicts between humans and double-crested cormorants (Phalacrocorax auritus) including harassment methods supplemented by lethal take. In this study we evaluated impacts or programs to harass spring migrating cormorants on the walleye (Sander vitreus) fishery in Brevoort Lake and the yellow perch (Perca flavescens ) and walleye fisheries at Drummond Island. Cormorant foraging declined significantly (p \u3c 0.05) at both locations subsequent to initiation of harassment programs. Overall harassment deteired 90% of cormorant foraging attempts while taking less than 6% lethally on average at each site. Yellow perch were a predominate prey item in number and biomass at both locations. Walleye made up a small proportion of the diet at both locations. However, both walleye and yellow perch abundance increased significantly (p\u3c0.05) at Drummond Island. Walleye abundance at age 3 increased to record levels in 2008 following 3 years of cormorant management at Brevoort Lake. The estimated cormorant consumption of age 1 walleye in the absence of management at Brevoort Lake during 2005 would account for 55% of the record 2006 age 1 walleye population. These results support the hypothesis, that cormorant predation on spawning aggregations of sportfish was a significant mortality factor and cormorant management reduced sportfish mortality and increased abundance at both locations. Continuation of harassment programs and .fishery assessments will determine whether improvement of targeted sport fisheries through control of spring migrating cormorants is sustainable
Reducing Impacts of Double-crested Cormorants to Natural Resources in Central New York: A Review of a Collaborative Research, Management, and Monitoring Program
Double-crested Cormorants (Phalacrocorax auritus) have used central New York waters for breeding and stopover habitats during migration since 1984. In response to public concern over Oneida Lake, the United States Department of Agriculture Wildlife Services and the New York State Department of Environmental Conservation initiated an integrated research, management and monitoring program aimed at mitigating cormorant impacts to fisheries and other natural resources in 1998. The history of this program was reviewed and efforts to reduce negative impacts of the Double-crested Cormorant population in central New York described. Management was successful, as demonstrated by a substantial decrease in cormorant use of Oneida Lake during spring, summer and fall seasons, and the apparent recovery of certain sportfish populations. Research identified cormorant movement patterns within and among water bodies and documented cormorant responses to hazing and other management techniques. The cormorant management program in central New York was intended to keep cormorant use of Oneida Lake at a level that prevents unsustainable impacts to fisheries populations
Identifying and Managing for Wildlife Damage During Stand Initiation
Trees in the Pacific Northwest (PNW) are susceptible to wildlife damage throughout their life cycles, and many industrial and nonindustrial forest landowners spend a good deal of money attempting to prevent or lessen this damage. Several species of animals affect forest regeneration and their damage can generally be broken into categories based on when damage occurs. During stand initiation, damage is seen with seeds, seedlings, and saplings. While some animals may cause damage only at one particular time, others damage trees at various intervals and in different ways. Methods of lethal and non-lethal control to reduce wildlife damage have been around for a long time and can be placed into five general categories: physical barriers, repellents, toxicants, hunting/trapping, and habitat manipulation. Unfortunately, there is no single tool or technique that works for all species in all situations, thus management can be complex and may require multiple techniques. Furthermore, some tools that appear to work may do so for only a short period of time.
Despite landowners\u27 best attempts to manage for their own values and objectives, they are potentially at risk from things outside their control, such as when adjacent landowners have very different objectives (e.g., a small tree farm adjacent to a large national park). Correctly identifying the source of damage, understanding the biology of the offending species, and knowing the pros and cons of management tools will help develop effective integrated management plans aimed to reduce damage affecting forest regeneration
Wildlife in managed forests: An overview of perspectives from the Pacific Northwest
1. Introduction- Humans rely on forests for fiber, food, water, shelter, recreation, inspiration, and various other benefits. Similarly, many species of native fauna depend on forests to meet their seasonal and annual requirements. Forests in the Pacific Northwest have a longstanding history of providing high quality forest products, and ownership across a complex matrix of forest stands is divided among provincial, federal, state, tribal, and private entities. Over time, requirements to provide forest products have increasingly rested with industrial and non-industrial private landowners. Concomitantly, forest management has evolved and intensified on private lands in response to increases in national and global demand for forest products, increasing urbanization, shifting policy on public forests, and a more complex regulatory environment
Evaluating SeaDust Wildlife Controllant™ as a Repellent to Reduce Deer Browse on Douglas-fir Seedlings
Herbivory by black-tailed deer affects growth form and survival of conifer seedlings in western Oregon and Washington, especially Douglas-fir. Several deterrents have been employed to reduce damage to forest resources yet most are ineffective or cost prohibitive. Use of chemical repellents is socially appealing because they offer a potential non-lethal alternative to reduce plant damage (i.e., browse). Commercial deer repellents may employ one or more mechanisms in their formulation, which affect taste, odor, visual, and/or tactile cues when consumed by deer. I evaluated the commercial SeaDust Wildlife Controllant™ as a tool to repel black-tailed deer from Douglas-fir seedlings during spring bud burst in western Oregon (mid-May through early July), because its ingredients have the potential to employ multiple avoidance mechanisms targeted on tactile, taste, and odor cues. Evidence indicated that deer browse was affected by an interaction of treatment and site; therefore, sites were evaluated separately. Treated seedlings were browsed less by deer than untreated seedlings on 2 of 3 tree farms where percent browse ranged from 0.08%-0.17% in treated plots and 0.15%-0.37% in control plots. Browse was similar at the third tree farm (0.15%). However, number of seedlings browsed in the third tree farm was greater than one site and less than the other, suggesting that statistical significance may not represent biological significance in this study. Future research is needed to incorporate acceptable loss to browsing and cost:benefit analyses
Effects of Black-tailed Deer and Roosevelt Elk Herbivory in Intensively Managed Douglas-fir Plantations
Black-tailed deer and Roosevelt elk are found throughout conifer-dominated Pacific Northwest forests west of the Cascade Crest, where they are important aesthetically, culturally, ecologically, and recreationally. Throughout their annual cycles, deer and elk use a variety of forest types and age classes to meet their basic requirements: food, water, cover, breeding, and young-rearing. Although their foraging strategies differ, black-tailed deer (browsers) and Roosevelt elk (grazers) often use the same forests. In general, forage plants for deer and elk are shade intolerant and are stimulated to grow when exposed to direct sunlight. As such, deer and elk often use clearcut patches following harvest. For Douglas-fir and other conifer species in the Pacific Northwest, the first five years after planting (i.e., stand initiation) is the most vulnerable period in which trees are exposed to wildlife damage, as young trees are within forage height and have not yet reached a free-to-grow condition. Because of this, foraging by deer and elk (hereafter, herbivory) has been documented as the most widespread form of damage in reforestation efforts in the Pacific Northwest
WADING BIRD MANAGEMENT AND RESEARCH ON NORTH AMERICAN AQUACULTURE FACILITIES
Aquaculture in North America varies geographically with respect to species cultured, annual production, size, complexity, and spatial arrangement of facilities. Species assemblages of predacious birds using aquaculture facilities also vary with many of these industry characteristics. Wading birds are highly adaptable, relatively ubiquitous throughout the aquaculture industry, and often associated with fish depredation problems at aquaculture facilities. Suitability of information regarding the impacts of wading birds to aquaculture varies dramatically by depredating species and industry sector. Great blue herons (Ardea herodias) cause considerable depredation losses on trout aquaculture in the Northeast, and current research suggests that little blue herons (Egretta caerulea) negatively impact baitfish aquaculture. Early research provided similar findings with great blue heron depredations on catfish aquaculture. Recent research however, initiated a paradigm shift in management by demonstrating that some wading birds like the great blue heron and great egret (Casmerodius albus) largely eat diseased catfish and consumption of healthy catfish can be limited by specific management efforts. However, information is lacking on other wading bird species and their impacts to cultured species such as baitfish and crawfish. Issues regarding wading bird depredations are dynamic and evolve with changing demographics of both the aquaculture industry and wading bird populations. Emerging issues include great blue herons as possible vectors for whirling disease in Northeastern trout aquaculture and predation on catfish by wood storks (Mycteria americana). As local, regional, and continental populations of wading birds continue to change in number and geographic distribution, it is imperative that research identify where and how aquaculture production losses occur and guide science-based management plans to abate production loss. We discuss current population status and trends for selected wading birds and their potential impacts and management on major aquaculture industries in the United States