Geology topics

Kelly A. Perkins

Publications and source records attributed to Kelly A. Perkins.

9 recordsLinked to original sources

USGS2024

Landscape-scale population trends in the occurrence and abundance of wildlife populations using long term camera-trapping data

Accurate estimation and monitoring of wildlife population trends is foundational to evidence-based conservation. Here, we use hierarchical modelling to estimate population trends for six species of management interest (coyotes; red foxes , white-tailed deer , gray foxes; eastern wild turkey , and bobcats) while accounting for observation error from a long-term camera trap survey conducted across the State of New York. We were able to detect population level trends in occurrence and abundance and produce spatially explicit predictions for all six species using a combination of single-species occupancy models and Royle-Nichols models. Coyote (mean λ = 1.22, 95 % CI = 0.85–1.82) and red fox (mean λ = 1.17, 95 % CI = 0.95–1.46) populations were widely distributed with stable populations across the sampling period from 2014 to 2021. White-tailed deer populations were highly abundant and displayed an increasing population trend (mean λ = 1.85, 95 % CI = 1.54–2.10). Eastern wild turkey occupancy remained low across the state despite displaying a slight increase in occupancy over the sampling period (mean ψ = 0.16, 95 % CI = 0.07–0.25). Gray fox occupancy was also low (mean ψ = 0.22, 95 % CI = 0.12–0.29), consistent with growing concerns over the species across North America. Despite recent recoveries elsewhere, bobcat populations in New York State displayed very low occupancy (mean ψ = 0.07, 95 % CI = 0.02–0.12), highlighting the necessity of monitoring to inform conservation action. We provide empirically supported management implications for each species and demonstrate the efficacy of long-term camera trapping to provide robust evidence on population trends while accounting for imperfect detections, over scales meaningful to species management and conservation.

Biological Conservation↗

USGS2022

Choosing an optimal duck season: Integrating hunter values and duck abundance

State wildlife agencies have long struggled to identify optimal hunting season dates for migratory game bird species that meet the diverse and often competing interests of stakeholders. Many approaches have been used to ensure the regulated community participates in the decision-making process, including public hearings, hunter season-date preference surveys, and hunter task forces or committees. Although hearings, surveys, and task force approaches include portions of the regulated community (typically the most avid) they may not necessarily reflect the opinions and values of all stakeholders. Additionally, these approaches rely heavily on limited anecdotal observations that may be unduly influenced by hunter avidity (e.g., days spent afield), hunter density, species preferences, and property access. To address the challenges caused by engaging only portions of the stakeholder community, we used a structured decision-making framework that included a 2017 duck hunter survey to elucidate values of a representative sample of the regulated community in each waterfowl hunting zone in the state of New York, USA. Rather than asking duck hunters about their specific duck hunting season date preferences, we asked them to rank 6 objectives describing what they value in their hunting experience (e.g., maximizing the opportunity to see mallards [ Anas platyrhynchos ] and black ducks [ Anas rubripes ], maximizing the number of weekend days). Four of the 6 objectives described duck species availability (i.e., abundance or immigration) and the remaining 2 described considerations that affect an individual hunter's opportunity or limitation to going duck hunting (i.e., holidays or conflicting hunting seasons). We used spatiotemporal abundance models derived from eBird citizen science data to estimate abundance and immigration rates of ducks in each waterfowl zone. We evaluated up to 9 unique season date alternatives developed by duck hunter task forces to determine which season date alternative best satisfied the competing objectives of duck hunters in each zone. The approach we developed allowed for selection of optimal duck hunting season dates and successfully involved avid duck hunters in the regulation development stages, while ensuring that the values of a representative sample of all stakeholders were directly considered through a clear and transparent decision-making process.

New York↗

USGS2021

Engaging hunters in selecting duck season dates using decision science: Problem framing, objective setting, devising management alternatives

Waterfowl hunters have an important economic impact on local, state, and national economies, and are important stakeholders in decisions regarding waterfowl harvest season dates. Individual states are responsible for annually setting duck season dates that conform to the migratory game bird season frameworks as set by the U.S. Fish and Wildlife Service. The federal framework specifies season length and bag limits (i.e., number of birds allowed to be harvested in a day), and states have the authority to select specific season dates within the federal guidelines. The state agency decision is largely centered on social objectives related to hunter satisfaction because the U.S. Fish and Wildlife Service incorporates biological objectives when establishing the federal framework to ensure sustainable waterfowl populations. This chapter describes the problem formulation, objectives, and alternatives steps of a decision analysis process used in New York. The authors demonstrate a process that allows for engagement by waterfowl hunters and incorporation of multiple stakeholder objectives, which can be used to evaluate tradeoffs to help guide decision making regarding selection of duck season dates. Engaging duck hunters through a task force and hunter survey provided opportunity for the regulated community to help shape season dates that quantitatively considered duck hunter satisfaction.

Book chapter↗

USGS2014

Avian response to timber harvesting applied experimentally to manage Cerulean Warbler breeding populations

Timber harvesting has been proposed as a management tool to enhance breeding habitat for the Cerulean Warbler ( Setophaga cerulea ), a declining Neotropical–Nearctic migratory songbird that nests in the canopy of mature eastern deciduous forests. To evaluate how this single-species management focus might fit within an ecologically based management approach for multiple forest birds, we performed a manipulative experiment using four treatments (three intensities of timber harvests and an unharvested control) at each of seven study areas within the core Cerulean Warbler breeding range. We collected pre-harvest (one year) and post-harvest (four years) data on the territory density of Cerulean Warblers and six additional focal species, avian community relative abundance, and several key habitat variables. We evaluated the avian and habitat responses across the 3–32 m 2 ha −1 residual basal area (RBA) range of the treatments. Cerulean Warbler territory density peaked with medium RBA (&sim;16 m 2 ha −1 ). In contrast, territory densities of the other focal species were negatively related to RBA (e.g., Hooded Warbler [ Setophaga citrina ]), were positively related to RBA (e.g., Ovenbird [ Seiurus aurocapilla ]), or were not sensitive to this measure (Scarlet Tanager [ Piranga olivacea ]). Some species (e.g., Hooded Warbler) increased with time post-treatment and were likely tied to a developing understory, whereas declines (e.g., Ovenbird) were immediate. Relative abundance responses of additional species were consistent with the territory density responses of the focal species. Across the RBA gradient, greatest separation in the avian community was between early successional forest species (e.g., Yellow-breasted Chat [ Icteria virens ]) and closed-canopy mature forest species (e.g., Ovenbird), with the Cerulean Warbler and other species located intermediate to these two extremes. Overall, our results suggest that harvests within 10–20 m 2 ha −1 RBA yield the largest increases in Cerulean Warblers, benefit additional disturbance-dependent species, and may retain closed-canopy species but at reduced levels. Harvests outside the optimum RBA range for Cerulean Warblers can support bird assemblages specifically associated with early or late (closed-canopy) successional stages.

Forest Ecology and Management↗

USGS2014

Selection of forest canopy gaps by male Cerulean Warblers in West Virginia

Forest openings, or canopy gaps, are an important resource for many forest songbirds, such as Cerulean Warblers ( Setophaga cerulea ). We examined canopy gap selection by this declining species to determine if male Cerulean Warblers selected particular sizes, vegetative heights, or types of gaps. We tested whether these parameters differed among territories, territory core areas, and randomly-placed sample plots. We used enhanced territory mapping techniques (burst sampling) to define habitat use within the territory. Canopy gap densities were higher within core areas of territories than within territories or random plots, indicating that Cerulean Warblers selected habitat within their territories with the highest gap densities. Selection of regenerating gaps with woody vegetation >12 m within the gap, and canopy heights >24 m surrounding the gap, occurred within territory core areas. These findings differed between two sites indicating that gap selection may vary based on forest structure. Differences were also found regarding the placement of territories with respect to gaps. Larger gaps, such as wildlife food plots, were located on the periphery of territories more often than other types and sizes of gaps, while smaller gaps, such as treefalls, were located within territory boundaries more often than expected. The creations of smaller canopy gaps, <100 m 2 , within dense stands are likely compatible with forest management for this species.

Wilson Journal of Ornithology↗

USGS2013

Comparison of point counts and territory mapping for detecting effects of forest management on songbirds

Point counts are commonly used to assess changes in bird abundance, including analytical approaches such as distance sampling that estimate density. Point-count methods have come under increasing scrutiny because effects of detection probability and field error are difficult to quantify. For seven forest songbirds, we compared fixed-radii counts (50 m and 100 m) and density estimates obtained from distance sampling to known numbers of birds determined by territory mapping. We applied point-count analytic approaches to a typical forest management question and compared results to those obtained by territory mapping. We used a before–after control impact (BACI) analysis with a data set collected across seven study areas in the central Appalachians from 2006 to 2010. Using a 50-m fixed radius, variance in error was at least 1.5 times that of the other methods, whereas a 100-m fixed radius underestimated actual density by >3 territories per 10 ha for the most abundant species. Distance sampling improved accuracy and precision compared to fixed-radius counts, although estimates were affected by birds counted outside 10-ha units. In the BACI analysis, territory mapping detected an overall treatment effect for five of the seven species, and effects were generally consistent each year. In contrast, all point-count methods failed to detect two treatment effects due to variance and error in annual estimates. Overall, our results highlight the need for adequate sample sizes to reduce variance, and skilled observers to reduce the level of error in point-count data. Ultimately, the advantages and disadvantages of different survey methods should be considered in the context of overall study design and objectives, allowing for trade-offs among effort, accuracy, and power to detect treatment effects.

Journal of Field Ornithology↗

USGS2013

Emulating natural disturbances for declining late-successional species: A case study of the consequences for Cerulean Warblers ( Setophaga cerulea )

Forest cover in the eastern United States has increased over the past century and while some late-successional species have benefited from this process as expected, others have experienced population declines. These declines may be in part related to contemporary reductions in small-scale forest interior disturbances such as fire, windthrow, and treefalls. To mitigate the negative impacts of disturbance alteration and suppression on some late-successional species, strategies that emulate natural disturbance regimes are often advocated, but large-scale evaluations of these practices are rare. Here, we assessed the consequences of experimental disturbance (using partial timber harvest) on a severely declining late-successional species, the cerulean warbler ( Setophaga cerulea ), across the core of its breeding range in the Appalachian Mountains. We measured numerical (density), physiological (body condition), and demographic (age structure and reproduction) responses to three levels of disturbance and explored the potential impacts of disturbance on source-sink dynamics. Breeding densities of warblers increased one to four years after all canopy disturbances (vs. controls) and males occupying territories on treatment plots were in better condition than those on control plots. However, these beneficial effects of disturbance did not correspond to improvements in reproduction; nest success was lower on all treatment plots than on control plots in the southern region and marginally lower on light disturbance plots in the northern region. Our data suggest that only habitats in the southern region acted as sources, and interior disturbances in this region have the potential to create ecological traps at a local scale, but sources when viewed at broader scales. Thus, cerulean warblers would likely benefit from management that strikes a landscape-level balance between emulating natural disturbances in order to attract individuals into areas where current structure is inappropriate, and limiting anthropogenic disturbance in forests that already possess appropriate structural attributes in order to maintain maximum productivity.

PLoS ONE↗

USGS2013

Management guidelines for enhancing Cerulean Warbler breeding habitat in Appalachian hardwood forests

The Cerulean Warbler (Setophaga cerulea) is a migratory songbird that breeds in mature deciduous forests of eastern North America. Cerulean Warblers (hereafter, ceruleans) require heavily forested landscapes for nesting and, within Appalachian forests, primarily occur on ridge tops and steep, upper slopes. They are generally associated with oakdominated (Quercus spp.) stands that contain gaps in the forest canopy, that have large diameter trees (>16 inches diameter breast height (dbh)), and that have well-developed understory-and upper-canopy layers. Ceruleans primarily use the midand upper-canopy where they glean insects from the surface of leaves and conceal their open cup nests. Because they are severely declining across much of their range (Fig. 1), habitat management is a high priority. Management for this species can also improve conditions for a number of other wildlife species that depend on the same structure.

Appalachian Mountains↗

USGS2012

Behavioral activities of male Cerulean Warblers in relation to habitat characteristics

Activities of 29 male Cerulean Warblers ( Setophaga cerulea ) were quantified on two sites in West Virginia during May–June 2005. Singing and foraging were the most common of 11 observed behavioral activities (81.6%), while maintenance and mating behaviors were uncommonly observed. Male activity differed among vegetative strata ( P = 0.02) with lower- and mid-canopy strata used most often (70% of observations), especially for foraging, perching, and preening. The upper-canopy was used primarily for singing, particularly within core areas of territories and in association with canopy gaps. Foraging occurred more than expected outside of core areas. Males were associated with canopy gaps during 30% of observations, but the distribution of behavioral activities was not significantly related ( P = 0.06) to gap presence. Males used 23 different tree species for a variety of activities with oaks ( Quercus spp.) used most often on the xeric site and black cherry ( Prunus serotina ) and black locust ( Robinia pseudoacacia ) on the mesic site. Tree species used for singing differed between core and non-core areas ( P < 0.0001) but distribution of singing and foraging activity did not differ among tree species ( P = 0.13). Cerulean Warblers appear to be flexible in use of tree species. Their use of different canopy strata for different behavioral activities provides an explanation for the affinity this species exhibits for a vertically stratified forest canopy.

Wilson Journal of Ornithology↗