DSpace Repository :: Browsing by Author "Williams, Christopher K."

Browsing by Author "Williams, Christopher K."

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A comparison of raptor densities and habitat use in Kansas cropland and rangeland ecosystems
(Journal of Raptor Research, 2000-09) Williams, Christopher K.; Applegate, Roger D.; Lutz, R. Scott; Rusch, Donald H.
We counted raptors on line transects along roads to assess densities, species diversity, and habitat selection of winter raptors between cropland and rangeland habitats in eastern Kansas. We conducted counts every 2 wk between September-March 1994-98. Species diversity indices did not differ between the two habitats (P -- 0.15). We calculated density estimates and cover type selection for Red- tailed Hawks (Buteojamaicensis), Northern Harriers (Circus cyaneus), and American Kestrels (Falco sparv- erius). Red-tailed Hawks and Northern Harrier densities were higher in cropland, while kestrel densities did not differ between the two habitats. All three species across both habitats had a general preference for idleland habitat. We believe three factors could explain the higher raptor densities in cropland: increased prey abundance, increased visibility of prey associated with harvested agriculture fields, and/ or a higher relative amount of preferred hunting habitat.
A Consideration of Wildlife in the Benefit-Costs of Hydraulic Fracturing: Expanding to an E3 Analysis
(Sustainability, 2022-04-17) Caldwell, Jennifer A.; Williams, Christopher K.; Brittingham, Margaret C.; Maier, Thomas J.
High-volume hydraulic fracturing (“fracking”) for natural gas in the Marcellus Shale (underlying about 24 mil ha in New York, Pennsylvania, Maryland, West Virginia, Ohio, and Virginia) has become a politically charged issue, primarily because of concerns about drinking water safety and human health. This paper examines fracking in the Marcellus region, and the tradeoffs between the energy and economic potential of natural gas extraction and the environmental impacts on wildlife. Therefore, we introduce a new E3 analysis that combines the costs and benefits as regards energy, economics, and the environment. The Marcellus Shale has the most proven reserves of natural gas of any basin in the United States, at 129 trillion cubic feet. Income from natural gas development comes primarily from direct and indirect jobs, and induced jobs (those created when direct workers spend their earnings in a community), taxes and fees, and royalty and lease payments to rights holders. Fracking, however, has detrimental effects on wildlife and wildlife habitats. Terrestrial habitat effects are primarily due to landscape fragmentation from the clearing of land for pipeline and well pad development, which often removes mature forest and creates open corridors and edge habitats. An increase in forest edge and open corridors is associated with shifts in the bird community, as generalist species that do well around people increase in abundance, while forest specialists decline. Invasive plants associated with disturbance further degrade forest habitats. Aquatic habitats are also affected, both directly and indirectly. Hydraulic fracturing requires up to 20 mil L of water per well fracture, most of which comes from surface water sources in the Marcellus region. The removal of water, especially in smaller headwaters, can increase sedimentation, alter water temperature and change its chemistry, resulting in reductions in aquatic biodiversity. Given the reality that hydraulic fracturing will continue, there is a need to develop practices that best minimize negative impacts on terrestrial and aquatic habitats, as well as policies and the resolve to enforce these practices. To achieve a more sustainable balance between economic, energy, and environmental costs and benefits, we recommend that industry, scientists, non-governmental organizations, mineral rights holders, landowners, and regulators work together to develop a set of best management practices that represent the best knowledge available.
A Mid-Atlantic and a National Population Model of Northern Bobwhite Demographic Sensitivity
(National Quail Symposium Proceedings, 2012) Williams, Christopher K.; Sandercock, Brett K.; Lohr, Michael; Castelli, Paul M.
Numerous field studies have estimated fecundity and survival rates for northern bobwhites (Colinus virginianus), but a synthetic population model based on life-stage simulation analysis (LSA) was only recently developed to examine demographic sensitivity of the finite rate of population change. We compare local demographic parameters of bobwhite versus a national compilation to identify limiting demographic factors for improved regional habitat planning and management. The national compilation provided a useful overview but combined parameters across populations at different latitudes and under different management regimes. We parameterized our LSA model to examine the sensitivity of the finite rate of growth (k) to simulated variation in 9 demographic parameters primarily estimated from field studies for one population in regional decline in New Jersey. Our model results predicted population declines in New Jersey (k 1⁄4 0.55) comparable to the national estimate (k 1⁄4 0.54), but notable differences occurred in sensitivity of demographic variables. The national model predicted winter survival of adults made the greatest contribution to variance of k (r2 1⁄4 0.42) followed by summer survival of adults (r2 1⁄4 0.13), and survival of chicks (r2 1⁄4 0.11). Our regional model for New Jersey also predicted winter and summer survival of adults would make the greatest contribution to variance of k (r2 1⁄4 0.33 and r2 1⁄4 0.13). The New Jersey model, in contrast to the national model, showed that annual variation in components of fecundity had a large effect on Var(k): including clutch size (r2 1⁄4 0.18 vs. national r2 1⁄4 0.01), nest success (r2 1⁄4 0.20 vs. national r2 1⁄4 0.06), and the number of young produced per nest that survived 30 days (r2 1⁄4 0.53 vs. national r2 1⁄4 0.16). Slopes of linear regression between simulated variation in each demographic variable against k were similar between the national and regional models. The slope for number of young produced per nest that survived 30 days with one exception was lower in the New Jersey data indicating more young are required to realize a stationary population. Our simulation results suggest management practices that improve winter survival or the number of young surviving 30 days will have the greatest potential to increase bobwhite population growth rate in New Jersey. Future linkage of models of demographic performance to experimental habitat manipulations will aid regional scientific planning to improve necessary habitat management.
A population model for management of Atlantic flyway resident population Canada geese
(Wildlife Society Bulletin, 2016-03-28) Beston, Julie A.; Williams, Christopher K.; Nichols, Theodore C.; Castelli, Paul M.
Highly abundant resident Canada geese (Branta canadensis) cause property damage throughout their range. Effective reduction and management of these populations requires knowledge of their population dynamics and responses to management actions. We used data from New Jersey, USA, and other resident Canada goose populations to produce stage-structured matrix models for resident Canada geese from both urban and rural landscapes. We ran stochastic simulations to assess 3 management activities for Atlantic Flyway Resident Population Canada geese: harvest, nest treatment, and cull. Unrealistic harvest rates, in excess of 10% for urban geese, would be needed to reduce the urban population to target levels within 10 years in the absence of other management activities. Nest treatment to prevent hatching is less controversial than culling adults, but as many as 62% of eggs in urban areas would need to be treated annually to sufficiently reduce the mean stochastic population growth rate. Cull would be the most effective way to achieve the population goal, but current cull rates are insufficient to reduce the urban population. Although reduction of urban geese was a challenge, current management activities in rural populations appeared to be sufficient to reduce populations. We also provide a simple spreadsheet tool for managers who want to explore management options for other resident Canada goose populations by inserting relevant vital rate estimates for their populations and manipulating management activities. © 2016 The Wildlife Society.
A portable aviary for field observations of behavior
(Journal of Field Ornithology, 2002-01-01) Van Why, Kyle R.; Williams, Christopher K.; Applegate, Roger D.; Flock, Brian E.
We describe a lightweight, portable, and inexpensive field aviary that was designed for observing Northern Bobwhite (Colinus virginianus) vigilance and feeding behavior. The general construction details of this aviary are easily modified to accommodate a variety of bird species and research objectives. SINOPSIS. Aviario portatil para hacer observaciones en el campo sobre la conducta de aves Describimos un aviario porta´til, liviano y de bajo costo disen˜ado para hacer estudios sobre la conducta alimentaria de Colinus virginianus. Los detalles en generales de construccio´n de este aviario se puede modificar fa´cilmente para acomodar una gran variedad de aves y diferentes objetivos de investigacio´n.
A Quantitative Summary of Attitudes toward Wolves and Their Reintroduction (1972-2000)
(Wildlife Society Bulletin, 2002) Williams, Christopher K.; Ericsson, Göran; Heberlein, Thomas A.
This paper reports an analysis of support for wolves (Canis spp.) reported in 38 quantitative surveys conducted between 1972 and 2000. Of 109 records reported in these surveys, a majority (51 %) showed positive attitudes toward wolves and 60% supported wolf restoration. Attitudes toward wolves had a negative correlation with age, rural residence, and ranching and farming occupations, and positive correlation with education and income. Thirty-five percent of ranchers and farmers surveyed had positive attitudes toward wolves. Among surveys of the general population samples, 61 % expressed positive attitudes. Surveys of environmental and wildlife groups showed an average of 69% support. Surveys in the lower 48 states showed higher proportions of positive attitudes than surveys in Scandinavia and Western Europe, where a majority did not support wolves. Among all surveys, 25% of respondents had neutral attitudes toward wolves. Positive attitudes toward wolves did not appear to be increasing over time. Because attitudes toward wolves are often not strong among the general public, they have the potential to change rapidly if linked to other, stronger attitudes and beliefs. We expect that progress in education and urbanization will lead to increasingly positive attitudes over time. Negative attitudes associated with age are probably a cohort effect, and we should not expect the aging populations in the United States and Europe to lead to more negative wolf attitudes. Paradoxically, successful wolf reintroductions are likely to reduce general positive sentiment, since the presence of wolves gives people a more balanced experience with the animals. Traditionally, people with the most positive attitudes toward wolves have been those with the least experience.
Addressing variability in estuarine food density for American black ducks
(Wildlife Society Bulletin, 2016-07-08) Goldstein, Marissa; Williams, Christopher K.; Castelli, Paul. M.; Duren, Kenneth R.
Habitat limitation and availability of food energy may be the cause of decline in American black duck (Anas rubripes) populations. Estimating food availability is a critical step in developing winter carrying-capacity estimates for black ducks. Recent research has estimated the biomass and energy supply of winter black duck foods in coastal marshes using a single-core sampling method, but estimates had large variability. We tested whether taking bulk core samples (i.e., homogenizing multiple core samples and subsampling a single core from it) at the same location (vs. a single core sample) would alter the mean and variance in food estimates in 7 different landscape–vegetation types (hereafter, habitat types: mudflat, subtidal, low marsh, high marsh, quasi-tidal pools, a tidal impoundment, and a freshwater impoundment) in coastal New Jersey, USA, during 2011. In all but one habitat type, there were no differences in the mean biomass or the mean energy density estimates for the single core samples and the bulk core samples, across all food types. Variance was reduced in subtidal and quasi-tidal pool habitats, but variance increased in tidal impoundments. Assessing time and cost-efficiency of bulk samples over single samples, cost per sample increased 4–12%/core. Because we observed little difference in food biomass, energy, and their respective variance estimates between single and bulk methods, while recording a slightly greater cost, we recommend researchers use the single-core sampling method to save both time and money. Further reductions in variance will likely need to be achieved through increased sample sizes. © 2016 The Wildlife Society.
Advancing Wildlife Policy of Eastern Timber Wolves and Lake Sturgeon through Traditional Ecological Knowledge
(Sustainability, 2022-03-24) Schley, Hannah L.; West, Ilene F.; Williams, Christopher K.
Traditional Ecological Knowledge (TEK) is becoming more prominent in wildlife management decisions and policy making. The cooperation of TEK and Western science paradigms have been beneficial for conserving our natural resources and wildlife populations. However, there are still concerns with accepting TEK as part of wildlife management, policy, and regulations. With increasing challenges to wildlife conservation, it is vital to implement Indigenous TEK to form more robust and holistic approaches to wildlife management. Here, we present two case studies in the upper Midwest region of the United States involving the Ojibwe tribe that show the importance of TEK collaboration and how that knowledge can be used for the betterment of ecologically sensitive species—lake sturgeon and eastern timber wolves.
Assessing Uncertainty in Coastal Marsh Core Sampling for Waterfowl Foods
(Journal of Fish and Wildlife Management, 2015-06-01) Ringelman, Kevin M.; Williams, Christopher K.; Coluccy, John M.
Quantifying foraging resources available to waterfowl in different habitat types is important for estimating energetic carrying capacity. To accomplish this, most studies collect soil-core samples from the marsh substrate, sieve and sort food items, and extrapolate energy values to wetland or landscape scales. This is a costly and time-intensive process; furthermore, extrapolation methods yield energy estimates with large variances relative to the mean. From both research and management perspectives, it is important to understand sources of this variation and estimate the number of soil cores needed to reduce the variance to desired levels. Using 2,341 cores collected from freshwater and salt marsh habitats at four sites along the Atlantic Coast, we examined sampling variation and biological variation among sites and habitats. When we removed extreme outliers in the data caused by large animal food items found in a small core sample, estimates of energy density decreased by an order of magnitude for most habitats. After removing outliers, we found inconsistent geographical variation among habitat types that was especially pronounced in freshwater and no evidence for within-season temporal depletion of food resources for any site or habitat. We used a Monte Carlo simulation approach to estimate the optimal number of cores (minimizing both cost and estimated variance) sampled in each habitat type. Across most contexts, a reduction in the coefficient of variation reached diminishing returns near 40 core samples. We recommend that researchers explicitly address outliers in the data and managers acknowledge the imprecision that can arise from including or excluding outliers when estimating energy density at landscape scales. Our results suggest that collecting 40–50 cores per habitat type was sufficient to reduce the variance to acceptable levels while minimizing overall sampling costs.
Assuring the future of prairie grouse: dogmas, demagogues, and getting outside the box
(Wildlife Society Bulletin, 2004-03) Applegate, Roger D.; Williams, Christopher K.; Manes, Robert R.
We discuss the necessity of a paradigm shift among managers toward dealing with the recovery and management of prairie grouse (Tympanuchus spp). To assure the future of these species, we will need to test dogmatic assumptions about grouse and their management and challenge the demagogues who insist on perpetuating untested “principles.” Tolerance for descriptive and qualitative studies is needed. Additionally, managers will need to remove themselves from the box and embrace landowners, theoretical biologists, economists, human-dimensions researchers, marketing and advertising specialists, and many other professionals outside the normal sphere of wildlife management. There is crucial need for a willingness to devise, test, and apply innovative ideas that are not normally considered in the management of grouse species, especially applying management to large areas within ecosystems. A comprehensive plan is needed to guide rangewide prairie grouse management. Planned management systems are needed to provide operational guidance in implementing species plans.
Determining Effective Riparian Buffer Width for Nonnative Plant Exclusion and Habitat Enhancement
(International Journal of Ecology, 2012-03-18) Ferris, Gavin; D'Amico, Vincent; Williams, Christopher K.
Nonnative plants threaten native biodiversity in landscapes where habitats are fragmented. Unfortunately, in developed areas, much of the remaining forested habitat occurs in fragmented riparian corridors. Because forested corridors of sufficient width may allow forest interior specializing native species to retain competitive advantage over edge specialist and generalist nonnative plants, identifying appropriate corridor widths to minimize nonnative plants and maximize ecosystem integrity is of habitat management concern. We measured the occurrences of 4 species of nonnative plants across the widths of 31 forested riparian corridors of varying widths in the White Clay Creek watershed of Pennsylvania and Delaware. Using repeated measures ANOVA, Japanese honeysuckle (Lonicera japonica) and multiflora rose (Rosa multiflora) prevalence did not significantly decline across buffer widths. However, garlic mustard (Alliaria petiolata) and oriental bittersweet (Celastrus orbiculatus) declined strongly within the first 15–25 m. Managing for riparian corridor widths a minimum of 15–25 m has the potential to enhance habitat quality but no corridor width (≤55 m) will exclude all invasive plants.
Do Invasive Fire Ants Affect Habitat Selection within a Small Mammal Community?
(International Journal of Ecology, 2010-12-27) Holtcamp, Wendee N.; Williams, Christopher K.; Grant, William E.
Animals must balance foraging with the need to avoid predators and risky habitats that decrease their fitness, and at the same time they must cope with competitors vying for habitat and resources. We examined how habitat selection and population density of four native small mammals were altered by the presence of red imported fire ants (Solenopsis invicta). When population size was low, hispid cotton rats (Sigmodon hispidus) and pigmy mice (Baiomys taylori) as well as white-footed mice (Peromyscus leucopus) used the “safe”, low fire ant habitat, as predicted by theories of density-dependent habitat selection. However, as fire ant population sizes expanded, cotton rats appeared to displace pigmy mice into the fire ant-dense grassland drainage while white-footed mice (Peromyscus leucopus) displaced all the other small mammals from low fire ant forest/brushland habitat.
Do Movement Patterns and Habitat Use Differ Between Optimal- and Suboptimal-sized Northern Bobwhite Coveys?
(National Quail Symposium Proceedings, 2017-11-08) Williams, Christopher K.; Applegate, Roger; Ives, Anthony R.
The group size of social animals and spatial structure of the environment can affect group behavior and movement decisions. Our objective was to investigate movement patterns and habitat use of northern bobwhite coveys (Colinus virginianus) of different size. Using radiotelemetry, we continuously monitored covey group size, daily movement, and habitat use on 12 independent 259-ha study areas in eastern Kansas, USA, during the winters between 1997 and 2000. We used correlated random walk models and fractal dimension models to determine if covey size affected movement characteristics or habitat selection. Intermediate-sized coveys (9–12 individuals, close to optimal covey size) exhibited daily movements that were substantially smaller and weekly home ranges that were more composed of woody escape cover than coveys of smaller or larger sizes. From the fractal dimension analyses, these coveys exhibited movement in between linear and a random walk at small spatial scales but very linear at large spatial scales. Large coveys had increased daily movement and tended to move in straighter lines (as indicated by the high proportion of turning angles [i.e., the angle between an initial direction and a new direction] around 0° and 180° and their multiscale fractal dimension) and they incorporated more cropland into their range, presumably to meet the feeding requirements of a larger group. In contrast, small coveys (1–4 individuals) tended to move more and increase the size of their home range, travel with a greater diversity of turning angles, and show movement patterns that were largely tortuous across a greater number of habitat patches at larger spatial scales (700 m). Small coveys have lower fitness and add new membership to increase fitness so it is possible that the movement behavior we observed represented a shift into a foray mode where bobwhites were searching for new membership. For areas with small populations and covey sizes, this information will help biologists better plan for habitat management to assist these coveys with their winter fitness.
Do Resident and Non-Resident Northern Bobwhite Hunters Self-Regulate Harvest Based on Population Size?
(National Quail Symposium Proceedings, 2012) Williams, Christopher K.; Applegate, Roger D.
A variety of factors influence the relative strength of additive and compensatory mortality of harvest on northern bobwhite (Colinus virginianus) including covey dynamics, habitat fragmentation, and timing of harvest. State wildlife agencies have long believed regulations could be liberal because hunters will self-regulate effort when populations decrease. A confounding observation is that with lower population abundances, hunter skill and harvest rate increases because the more novice hunters do not participate. This raises the question whether non-resident small game hunters could have a larger impact at lower population levels if they have (1) more money to dedicate to out of state licenses and travel/lodging, and (2) time to dedicate to the hunting experience? We examined long-term bobwhite population and harvest data from Kansas (1966–1999) to learn if self-regulation differed between resident and non-resident small game hunters. The number of resident and non-resident small game hunters was related to their respective harvest of northern bobwhites. Decreasing October population index was associated with a decline in the number of resident bobwhite hunter days and harvest. Conversely, increasing numbers of non-resident hunters participated in the hunting season with higher hunter efficiency and a larger harvest at lower October population index levels. Total relative harvest decreased overwinter (Oct–Jan) survival. The Kansas resident bobwhite harvest is probably self-regulatory but non-resident harvest is not. Future harvest regulations should consider the impact of non-resident harvest.
Does Invasive Common Reed in Coastal Salt Marshes Affect Dabbling Duck Food Availability?
(Journal of Fish and Wildlife Management, 2020-06-26) Van Neste, Kristen M.; Williams, Christopher K.; Castelli, Paul M.
Common reed, Phragmites australis, a nonnative perennial grass, is considered a nuisance species to land managers and wildlife biologists. Common reed thrives in areas with reduced soil salinities, increased nitrogen availability, and anthropogenic shoreline development. The expansion of nonnative common reed into tidal wetlands of North America detrimentally affects native wildlife by altering resource utilization, modifying trophic structures, and changing disturbance regimes. Thus, it also has the potential to drastically affect dabbling duck (Family Anatidae, SubFamily Anatinae, Tribe Anatini) energetic carrying capacity in salt marsh ecosystems. We assessed whether invaded monocultures of common reed in dabbling duck habitat could alter the availability of invertebrate and seed foods for the mallard Anas platyrhynchos, American black duck Anas rubripes, green-winged teal Anas crecca, northern shoveler Spatula clypeata, and northern pintail Anas acuta as compared with wetland type (mudflat, low marsh, high marsh, and impoundments). We compared food and energy availability in > 90% common reed monocultures with noncommon reed-invaded salt marshes in five study areas in Edwin B. Forsythe National Wildlife Refuge, New Jersey, 2015–2016. To estimate wetland-specific food energy supply, we collected sediment core samples, fixed them with formalin, and washed, dried, sorted, and weighed them for seeds and invertebrates. We multiplied biomass (g) by true metabolizable energy values to estimate species-specific dabbling duck food energy availability. We further estimated wetland-specific energetic carrying capacity (duck energy days) on the basis of known species-specific energetic demands. We determined that duck energy days/ha were greater for dabbling ducks in wetlands invaded with common reed because they contained more consumable seed energy and less consumable invertebrate energy. However, future research should explore how accessible these foods are when common reed grass is dense. To aid in restoration efforts once common reed is removed by control efforts, our results indicate that a robust seed bank exists in the soil strata, thus increasing salt-marsh seed biodiversity.
Effects of broadcasting calls during surveys to estimate density and occupancy of northern bobwhite
(Wildlife Society Bulletin, 2012-03-23) Duren, Kenneth R.; Buler, Jeffrey J.; Jones, William L.; Williams, Christopher K.
We assessed the effects of using a broadcast caller during surveys and increasing survey duration to estimate northern bobwhite (Colinus virginianus) density and occupancy. From 15 May 2009 to 15 August 2009, we conducted repeat-visit breeding bobwhite surveys at 180 sites in Delaware, USA. Increasing survey duration from 3 min to 7 min, or using a broadcast caller, improved detection probability for a single visit by 52% and 42%, respectively. However, density estimates when using a broadcast caller were biased high—≥3 times greater compared to passive-listening surveys. Density estimates for 3-min and 7-min passive surveys were not different. Additionally, bobwhite occupancy was similar among all 3 survey treatments. Use of a broadcast caller to survey for bobwhites appears to violate the assumption of distance sampling that an individual is detected prior to movement. Use of a broadcast caller is inappropriate for determining density estimates through distance sampling, but may be appropriate for determining site occupancy. © 2011 The Wildlife Society.
Estimating habitat carrying capacity for migrating and wintering waterfowl: considerations, pitfalls and improvements
(Wildfowl, 2014) Williams, Christopher K.; Dugger, Bruce D.; Brasher, Michael G.; Coluccy, John M.; Cramer, Dane M.; Eadie, John M.; Gray, Matthew J.; Hagy, Heath M.; Livolsi, Mark; McWilliams, Scott R.; Petrie, Mark; Soulliere, Gregory J.; Tirpak, John M.; Webb, Elizabeth B.
Population-based habitat conservation planning for migrating and wintering waterfowl in North America is carried out by habitat Joint Venture (JV) initiatives and is based on the premise that food can limit demography (i.e. food limitation hypothesis). Consequently, planners use bioenergetic models to estimate food (energy) availability and population-level energy demands at appropriate spatial and temporal scales, and translate these values into regional habitat objectives. While simple in principle, there are both empirical and theoretical challenges associated with calculating energy supply and demand including: 1) estimating food availability, 2) estimating the energy content of specific foods, 3) extrapolating site-specific estimates of food availability to landscapes for focal species, 4) applicability of estimates from a single species to other species, 5) estimating resting metabolic rate, 6) estimating cost of daily behaviours, and 7) estimating costs of thermoregulation or tissue synthesis. Most models being used are daily ration models (DRMs) whose set of simplifying assumptions are well established and whose use is widely accepted and feasible given the empirical data available to populate such models. However, DRMs do not link habitat objectives to metrics of ultimate ecological importance such as individual body condition or survival, and largely only consider food-producing habitats. Agent-based models (ABMs) provide a possible alternative for creating more biologically realistic models under some conditions; however, ABMs require different types of empirical inputs, many of which have yet to be estimated for key North American waterfowl. Decisions about how JVs can best proceed with habitat conservation would benefit from the use of sensitivity analyses that could identify the empirical and theoretical uncertainties that have the greatest influence on efforts to estimate habitat carrying capacity. Development of ABMs at restricted, yet biologically relevant spatial scales, followed by comparisons of their outputs to those generated from more simplistic, deterministic models can provide a means of assessing degrees of dissimilarity in how alternative models describe desired landscape conditions for migrating and wintering waterfowl.
Estimating Waterfowl Carrying Capacity at Local Scales: A Case Study From Edwin B. Forsythe National Wildlife Refuge, New Jersey
(Journal of Fish and Wildlife Management, 2018-01-29) Ringelman, Kevin M.; Williams, Christopher K.; Castelli, Paul M.; Sieges, Mason L.; Longenecker, Rebecca A.; Nichols, Theodore C.; Earsom, Stephen D.
The management of wintering North American waterfowl is based on the premise that the amount of foraging habitat can limit populations. To estimate carrying capacity of winter habitats, managers use bioenergetic models to quantify energy (food) availability and energy demand, and use results as planning tools to meet regional conservation objectives. Regional models provide only coarse estimates of carrying capacity because habitat area, habitat energy values, and temporal trends in population-level demand are difficult to quantify precisely at large scales. We took advantage of detailed data previously collected on wintering waterfowl at Edwin B. Forsythe National Wildlife Refuge and surrounding marsh, New Jersey, and created a well-constrained local model of carrying capacity. We used 1,223 core samples collected between 2006 and 2015 to estimate food availability. We used species-specific 24-h time–activity data collected between 2011 and 2013 to estimate daily energy expenditure, morphometrically corrected for site- and day-specific thermoregulatory costs. To estimate population-level energy demand, we used standardized monthly ground surveys (2005–2014) to create a migration curve, and proportionally scaled that to fit aerial survey data (2005–2014). Crucially, we also explicitly incorporated estimates of variance in all of these parameters and conducted a sensitivity analysis to diagnose the most important sources of variation in the model. Our results from an outlier-removed, a strict depletion model indicated that at estimated mean levels of supply (923 million kcal) and cumulative demand (3.4 billion kcal), refuge food resources were depleted before November. However, a constant-supply model that represented tidal replenishment of resources indicated that just enough energy was present to sustain peak winter populations. Variation in model output appeared to be driven primarily by uncertainty in population abundance during peak periods of use, emphasizing a new management focus on studying migration chronologies of waterfowl. This model allows for relative assessment of biases and uncertainties in carrying-capacity modeling, and serves as a framework identifying critical science needs to improve local and regional waterfowl management planning.
Evaluation of a clutch-containment method during hatch in geese: Using resident Canada geese as an example
(Wildlife Society Bulletin, 2012-04-10) Guerena, Katherine B.; Castelli, Paul M.; Nichols, Theodore C.; Williams, Christopher K.
Disruption associated with nest visits during the hatch period of waterfowl can cause partial abandonment of hatchlings, potentially causing bias in the survival of marked birds. We evaluated the use of a mesh clutch-containment bag to capture and mark entire broods of 151 resident Canada goose (Branta canadensis) nests, prior to hatch, while minimizing observer-caused disruption during brooding. The study was conducted in New Jersey, USA, from April to June 2010. No differences were found in hatch success or the number of hatchlings marked between contained clutches and the control group. Although this technique was not beneficial in studying gosling survival in temperate nesting populations, it may be effective in sub-Arctic nesting conditions where nest visits are conducted using a more invasive approach such as a helicopter. © 2012 The Wildlife Society.
Evolving wildlife management cultures of governance through Indigenous Knowledges and perspectives
(The Journal of Wildlife Management, 2024-04-17) Fisk, Jonathan James; Leong, Kirsten Mya; Berl, Richard E. W.; Long, Jonathan W.; Landon, Adam C.; Adams, Melinda M.; Hankins, Don L.; Williams, Christopher K.; Lake, Frank K.; Salerno, Jonathan
Within governance agencies, academia, and communities alike, there are increasing calls to recognize the value and importance of culture within social-ecological systems and to better implement Indigenous sciences in research, policy, and management. Efforts thus far have raised questions about the best ethical practices to do so. Engaging with plural worldviews and perspectives on their own terms reflects cultural evolutionary processes driving paradigm shifts in 3 fundamental areas of natural resource management: conceptualizations of natural resources and ecosystems, processes of public participation and governance, and relationships with Indigenous Peoples and communities with differing worldviews. We broadly describe evolution toward these paradigm shifts in fish and wildlife management. We then use 3 case studies to illustrate the ongoing cultural evolution of relationships between wildlife management and Indigenous practices within specific historical and social-ecological contexts and reflect on common barriers to appropriately engaging with Indigenous paradigms and lifeways. Our case studies highlight 3 priorities that can assist the field of wildlife management in achieving the changes necessary to bridge incommensurable worldviews: acknowledging and reconciling historical legacies and their continued power dynamics as part of social-ecological systems, establishing governance arrangements that move beyond attempts to extract cultural information from communities to integrate Indigenous Knowledges into dominant management paradigms, and engaging in critical reflexivity and reciprocal, accountable relationship building. Implementing these changes will take time and a commitment to processes that may initially feel uncomfortable and unfamiliar but have potential to be transformative. Ethical and culturally appropriate methods to include plural and multivocal perspectives and worldviews on their own terms are needed to transform wildlife management to achieve more effective and just management outcomes for all.

Browsing by Author "Williams, Christopher K."

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