Humburg D.D.,Ducks Unlimited Inc. |
Anderson M.G.,Institute for Wetland and Waterfowl Research
The North American Waterfowl Management Plan (NAWMP) is a continental ecosystems model for wildlife conservation planning with worldwide implications. Since established in 1986, NAWMP has undergone continual evolution as challenges to waterfowl conservation have emerged and information available to support conservation decisions has become available. In the 2012 revision, the waterfowl management community revisited the fundamental basis for the Plan and placed greater emphasis on sustaining the Plan's conservation work and on integration across disciplines of harvest and habitat management. Most notably, traditional and nontraditional users (i.e. hunters and wildlife viewers) of the resource and other conservation supporters are integrated into waterfowl conservation planning. Challenges ahead for the waterfowl management enterprise include addressing tradeoffs that emerge when habitat for waterfowl populations versus habitat for humans are explicitly considered, how these objectives and decision problems can be linked at various spatial and temporal scales, and most fundamentally how to sustain NAWMP conservation work in the face of multi-faceted ecological and social change. © Wildfowl & Wetlands Trust. Source
Plattner D.M.,Southern Illinois University Carbondale |
Eichholz M.W.,Southern Illinois University Carbondale |
Yerkes T.,Ducks Unlimited Inc.
Journal of Wildlife Management
A bioenergetic approach has been adopted as a planning tool to set habitat management objectives by several United States Fish and Wildlife Service North American Waterfowl Management Plan Joint Ventures. A bioenergetics model can be simplified into 2 major components, energetic demand and energetic supply. Our goal was to estimate habitat-specific food availability, information necessary for estimating energy supply for black ducks (Anas rubripes) wintering on Long Island, New York, USA. We collected both nektonic and benthic samples from 85 wetland sites dispersed among 5 habitat types (salt marsh, mud flat, submersed aquatic vegetation, brackish bay, and freshwater) commonly used by black ducks in proportion to expected use. Biomass varied among habitats (F4,5 > 7.46, P < 0.03) in 20042005, but there was only marginal variation in 20052006 (F3,4 =5.75, P =0.06). Mud flats had the greatest biomass (1,204 kg/ha, SE 532), followed by submersed aquatic vegetation (61 kg/ha, SE 18), and salt marsh (34 kg/ha, SE =6). In the second year of the study, freshwater had the greatest biomass (306 kg/ha, SE =286), followed by mud flats (85 kg/ha, SE =63), and salt marsh (35 kg/ha, SE =4). Our results suggest food density on wintering grounds of black ducks on coastal Long Island is considerably lower than for dabbling ducks using inland freshwater habitats, indicating black duck populations are more likely than other species of dabbling ducks to be limited by winter habitat. We recommend targeting preservation, restoration, and enhancement efforts on salt marsh habitat. © 2010 The Wildlife Society. Source
Smith A.,Ducks Unlimited Inc.
Journal of Spatial Science
This paper describes an approach to using the Random Forest classification algorithm to quantitatively evaluate a range of potential image segmentation scale alternatives in order to identify the segmentation scale(s) that best predict land cover classes of interest. The image segmentation scale selection process was used to identify three critical image object scales that when combined produced an optimal level of land cover classification accuracy. Following segmentation scale optimization, the Random Forest classifier was then used to assign land cover classes to 11 scenes of SPOT satellite imagery in North and South Dakota with an average overall accuracy of 85.2 percent. © 2010 Surveying and Spatial Sciences Institute and Mapping Sciences Institute, Australia. Source
Peron G.,Colorado State University |
Peron G.,U.S. Geological Survey |
Walker J.,Ducks Unlimited Inc. |
Rotella J.,Montana State University |
And 2 more authors.
Birds and their population dynamics are often used to understand and document anthropogenic effects on biodiversity. Nest success is a critical component of the breeding output of birds in different environments; but to obtain the complete picture of how bird populations respond to perturbations, we also need an estimate of nest abundance or density. The problem is that raw counts generally underestimate actual nest numbers because detection is imperfect and because some nests may fail or fledge before being subjected to detection efforts. Here we develop a state-space superpopulation capture-recapture approach in which inference about detection probability is based on the age at first detection, as opposed to the sequence of re-detections in standard capture-recapture models. We apply the method to ducks in which (1) the age of the nests and their initiation dates can be determined upon detection and (2) the duration of the different stages of the breeding cycle is a priori known. We fit three model variants with or without assumptions about the phenology of nest initiation dates, and use simulations to evaluate the performance of the approach in challenging situations. In an application to Blue-winged Teal Anas discors breeding at study sites in North and South Dakota, USA, nesting stage (egg-laying or incubation) markedly influenced nest survival and detection probabilities. Two individual covariates, one binary covariate (presence of grazing cattle at the nest site), and one continuous covariate (Robel index of vegetation), had only weak effects. We estimated that 5-10% of the total number of nests were available for detection but were missed by field crews. An additional 6-15% were never available for detection. These percentages are expected to be larger in less intense, more typical sampling designs. User-friendly software nestAbund is provided to assist users in implementing the method. © 2014 by the Ecological Society of America. Source
Lindberg M.S.,University of Alaska Fairbanks |
Schmidt J.H.,National Park Service |
Walker J.,Ducks Unlimited Inc.
Journal of Wildlife Management
We examined changes in the pathways used for inference in The Journal of Wildlife Management (JWM) and 2 other applied journals during recent decades. Although null hypothesis significance testing is still the main approach to inference, use of information-theoretic approaches based on Akaike's Information Criterion (AIC) has rapidly grown to be a common form of inference in JWM and related journals. We observed little growth in the use of other information criteria such as Bayesian Information Criterion (BIC). The use of information criteria for multimodel inference has addressed some of the criticisms of significance testing. However, information criteria still needs to be used appropriately with a priori hypotheses to be valid. In addition, much work remains to be done on application of information criteria to more complex models such as hierarchical and Bayesian models. © 2015 The Wildlife Society. Source