Mark Weckel | American Museum of Natural History (original) (raw)
Papers by Mark Weckel
Ecological Modelling, 2013
In the northern suburbs of NYC, land managers have begun implementing bow-only hunts to reduce o... more In the northern suburbs of NYC, land managers have begun implementing bow-only hunts to reduce
overabundant white-tailed deer (Odocoileus virginianus) herds in an effort to promote forest regeneration.
However, there have been no attempts to model the impact of bow hunting on deer population growth.
Using harvest statistics from the Mianus River Gorge Preserve in Westchester County, NY we simulated
the impact of bow hunting on a population of female deer exhibiting density-dependent growth and
explored a range of carrying capacities, immigration rates, and harvest intensities. Simulated bow hunting
(adult harvest
≥
1.8 females km−2) was capable of achieving deer densities believed necessary for forest
regeneration (2.9 females km−2) in closed populations where carrying capacity = 13.8 females km−2, representing
the lower end of deer overabundance. At this carrying capacity and low immigration rates,
the impact of bow hunting was more variable, producing population declines ranging from 20 to 70%
contingent on harvest rates. Hours per harvest increased rapidly as the deer population declined requiring
nearly 5 times the hourly effort as female density approached target levels. Sustaining harvests over
multiple decades, particularly as effort per deer harvest increases, is one of the biggest challenges facing
bow-only hunts. As controlled bow hunts are executed by volunteer sportsmen, reductions will be determined
by hunters’ capacity or willingness to increase effort and efficiency. Bow hunting will therefore
likely result in deer densities lower than historical peak values, yet higher than is currently assumed
necessary for forest regeneration.
Bookmarks Related papers MentionsView impact
Northeastern Naturalist, 2011
We characterized the landscape-level habitat use of Megascops asio (Eastern Screech Owl) in a su... more We characterized the landscape-level habitat use of Megascops asio (Eastern
Screech Owl) in a suburban/urban region of New York and Connecticut using citizenscience
methodologies and GIS-based land-use information. Volunteers sampled their
properties using call-playback surveys in the summers of 2009 and 2010. We modeled
detection and occupancy as functions of distance to forest and two coarse measures
of development. AICc-supported models were validated with an independent dataset
collected by trained professionals. Validated models indicated a negative association
between occupancy and percent forest cover or, similarly, a positive association with
percent impervious cover. When compared against the systematic dataset, models that
used forest cover as a predictor had the highest accuracy (kappa = 0.73 ± 0.18) in predicting
the occupancy observations in the systematic survey. After accounting for detection,
both datasets support similar owl-habitat patterns of predicting occupancy in developed
areas compared to highly rural. While there is likely a minimum amount of forest cover
and/or maximum level of urbanization that Screech Owls can tolerate, such limits appear
to be beyond the ranges sampled in this study. Future research that seeks to determine
this development limit should focus on very urbanized areas. The high accuracy of the
citizen-science models in predicting the systematic dataset indicates that volunteer-based
efforts can provide reliable data for wildlife studies.
Bookmarks Related papers MentionsView impact
Wildlife Society Bulletin, 2011
Jacobson et al.’s (1997) individual branch-antlered male (IBAM) method is a popular camera techn... more Jacobson et al.’s (1997) individual branch-antlered male (IBAM) method is a popular camera
technique for estimating white-tailed deer (Odocoileus virginianus) abundance. Demographic ratios are
estimated from raw photographic occurrences (RPO) of males, females, and fawns. Point abundance
estimates of each group are estimated by using said ratios to extrapolate from a count of uniquely identifiable
males. In 2009, using camera-trap data from the Mianus River Gorge Preserve (NY), we modified the IBAM
technique to 1) generate measures of uncertainty for parameter estimates via bootstrapping camera stations,
and 2) address the concern that RPO ratios may be biased if groups of animals differ in their probability of
being photographed (e.g., trap success [TS]). For each sex–age group, we evaluated RPO as a function of TS
using linear regression to generate photographic counts standardized by TS (standardized photographic
occurrences [SPO]). We generated estimates of sex–age ratios and abundances using both RPO and SPO. To
evaluate the accuracy of using SPO in conjunction with the IBAM method, we independently estimated the
abundance of a marked group of female deer using a Poisson log normal (PNE) mark–resight estimator.
Abundance estimates across sex–age classes were most similar between PNE and IBAM when SPO
demographic ratios were used. Owing to the greater TS of females, using SPO discounted the relative
abundance of females and, thus, lowered the female:male ratios and raised the fawn:female ratio. Uncertainty
was broad across all approaches, yet accounting for TS reduced the confounding variability owing to
differences in detection probability and generated more accurate parameter estimates.
Bookmarks Related papers MentionsView impact
Wildlife Society Bulletin, 2011
Over the last decade, wildlife professionals in the New York City (NY, USA) metropolitan area ha... more Over the last decade, wildlife professionals in the New York City (NY, USA) metropolitan area
have increasingly turned to controlled archery hunts to reduce overabundant suburban deer populations. The
success of these deer management programs (DMPs) depends on a willing pool of hunters motivated to meet
harvest goals. This requires maintaining hunter satisfaction both now, and in the future when successful herd
reduction will result in fewer opportunities for deer harvest. With the goal of providing local deer managers
with feedback from hunters partaking in DMPs, we used surveys designed to evaluate why members hunted,
why they joined DMPs, members’ views on deer management, and ultimately, their satisfaction with
controlled hunts. Members were primarily motivated to hunt by the chance to see wildlife, opportunities
for recreation, and a passion for archery. Most (71%) reported that their enjoyment had increased since first
joining a DMP and satisfaction was not linked to harvest opportunity or success. Nevertheless, we
documented several trends that threaten the long-term sustainability of DMPs. First, 78.2% of survey
respondents were over the age of 40, possibly suggesting fewer younger recruits into DMPs. Second, the
opportunity to hunt previously unhunted land, a transitory incentive, was the most common reason for
participating in DMPs. Third, respondents whose DMP doe harvest was limited by choosing to spend time
on private, non-DMP land were also more likely to have seen fewer deer on DMP lands (G-test ¼ 13.2,
df ¼ 4, P ¼ 0.01). This suggests that effort will decline as deer herds decline.
Bookmarks Related papers MentionsView impact
Insecta Mundi, 2011
The southern Appalachian millipeds Boraria stricta (Brölemann, 1896) and B. infesta (Chamberlin, ... more The southern Appalachian millipeds Boraria stricta (Brölemann, 1896) and B. infesta (Chamberlin,
1918) (Diplopoda: Polydesmida: Xystodesmidae) have become established in Westchester Co., New York, and
Hartford Co., Connecticut, respectively. Only three individuals are available for the latter, but B. stricta has
established a reproducing population in southern New York state. This species is also recorded from Bland Co.,
Virginia, in the Ridge and Valley Physiographic Province. Boraria profuga (Causey, 1955) comprises two allopatric
populations, one in Montgomery Co., Arkansas, and the other in Ouachita Parish, Louisiana. Distributional records
and gonopod drawings are presented for these species plus B. deturkiana (Causey, 1942).
Bookmarks Related papers MentionsView impact
Wildlife Biology in Practice, 2012
We evaluated the accuracy of a previously published model of coyote (Canis latrans) sightings in ... more We evaluated the accuracy of a previously published model of coyote (Canis latrans) sightings in suburban Westchester County, New York. This model was originally developed using citizen reports of coyote sightings to predict the probability of a human-coyote interaction based on proximity to habitat features. Because the data were obtained from surveys, researchers could not separate patterns of site occupancy by coyotes from possible patterns of detection by respondents. Nevertheless, the model could be an indicator of site occupancy within the suburban matrix. We sought to evaluate the predictive power of the human-coyote interaction model with data gathered via a more rigorous method. To build a set of validation sites, we surveyed 11 parks in Westchester County and one park in Bronx County, NY with camera traps between April and October of 2010. The probability of photographing a coyote in a single trap-night was 0.06 ± 0.12 and all sites had >0.9 probability of detecting a coyote at least once given the total trap-nights at each site. During validation, we also added four additional sites that had been surveyed by other researchers with camera traps as additional “present” sites. Predictions of coyote presence or absence based on the human-coyote interaction model for these 16 validation sites were compared to the observed survey results. The model, which contained distances to forest, grassland, and pooled medium and high development performed well in predicting the observed data (kappa = 0.75 ± 0.17, Area-Under-Curve of Receiver-Operator-Characteristic plots = 0.90). The model appears to sufficiently predict coyote occupancy in a suburban-urban landscape and will form the basis of for development of a more comprehensive model of coyote distribution in the New York City metropolitan area. Furthermore, its accuracy illustrates how citizen science can provide reliable estimates of wildlife-habitat patterns in urban areas.
Bookmarks Related papers MentionsView impact
Urban Habitats, 2009
Japanese stilt grass (Microstegium vimineum) is an invasive grass in the eastern and midwestern U... more Japanese stilt grass (Microstegium vimineum) is an invasive grass in the eastern and midwestern United States. It tolerates a wide range of light and moisture conditions and has readily replaced native herbaceous vegetation in many areas. Despite its detrimental effects, Japanese stilt grass does provide some benefit, serving as habitat for ground amphibians such as frogs and toads (anurans) in areas where populations of white-tailed deer (Odocoileus virginianus) have depleted native herbaceous cover. We investigated relative abundances of common anuran species both inside and outside of a stilt grass invasion front in a Northeastern mixed hardwood forest. We used pitfall trap arrays to sample anuran species during the summers of 2006 and 2007 and we captured four species: wood frog (Rana sylvatica); pickerel frog (Lithobates palustris); spring peeper (Pseudacris crucifer); and American toad (Bufo americanus). We captured more individuals from each of these species in stilt grass plots. Too few spring peepers were captured for analysis, so we modeled the captures of the three remaining species—wood frog, pickerel frog, and American toad—with negative binomial regression against stilt grass presence/absence, soil moisture, soil temperature, and relative humidity. We compared models containing these parameters using AIC (Akaike's Information Criterion), a common information criterion used in model selection. All three species selected stilt grass plots, but appeared to do so for different reasons. Pickerel and wood frogs seemed to select primarily areas of high soil moisture, which was consistently greater in stilt grass plots. American toads selected stilt grass areas and areas of high humidity, though humidity did not vary according to stilt grass presence or absence. For all three species, stilt grass seemed to provide habitat value beyond any causal or correlative relationship with microclimate. These results suggest that some invasive species of herbaceous cover provide alternative habitat for native wildlife in degraded communities. Managers need to consider the effect on wildlife when considering removal of invasives, particularly when there is little native habitat and when removal would be destructive.
Bookmarks Related papers MentionsView impact
Journal of Wildlife Management, 2010
The expansion of coyotes (Canis latrans) into the northeastern United States is a major challenge... more The expansion of coyotes (Canis latrans) into the northeastern United States is a major challenge to wildlife professionals,
especially in suburban and urban areas where reports of human–coyote interaction (HCI) are on the rise. To assist wildlife professionals in
identifying potential hot spots of interaction and homeowners in evaluating their risk of a backyard encounter, we used the techniques of citizen
science to build a landscape model of HCI for suburban residential properties in Westchester County, New York, USA. We distributed surveys
via school children (kindergarten to grade 12) as part of a voluntary class assignment, to maximize the number of homeowners participating in
our study and to provide learning experiences for students. Of 6,000 surveys distributed to schools, .1,500 students interviewed their parents
on whether a coyote had been seen or heard on their property from 2003 to 2006. Although surveys could not be distributed randomly owing to
the participatory process of individual schools, we did receive responses from across Westchester County, representing the spectrum from the
most rural to the most urban towns. Homeowners who encountered (i.e., seen or heard) a coyote on their property were on average 50% closer
to forest, 36% closer to grassland, and 66% farther from medium- to high-intensity development, complementing existing knowledge on urban
coyote habitat use. Our model seemed robust in predicting an independent set of coyote observations (r 5 0.88). Based on this model, we
generated a map describing the probability of HCI that can be used by both wildlife professionals and homeowners. Regarding the former, state
wildlife agencies could more precisely target education campaigns on how to live with coyotes where the possibility of HCI was greatest.
Homeowners, in turn, could evaluate their own risk and modify behaviors that would make their property less attractive to coyotes.
Furthermore, in creating a descriptive model of HCI from citizen-generated data, we demonstrated how citizen science can be a useful
exploratory tool, generating a wealth of data over a large geographic area in a short period, especially when the inquest is appropriate to
stakeholder participation in data collection.
Bookmarks Related papers MentionsView impact
Forest Ecology and Management, 2006
Eastern hemlock (Tsuga canadensis; hereafter hemlock) was once relatively common in the northeast... more Eastern hemlock (Tsuga canadensis; hereafter hemlock) was once relatively common in the northeastern United States. However, recent
disturbances – including exotic pests and white-tailed deer overpopulation – have exacerbated declines in hemlock forest in the 20th century. As a
previously undisturbed stand, the Mianus River Gorge Preserve (MRGP) provided an ideal site to investigate the potential impact of these factors
on the structure and composition of old-growth hemlock forests. The woody vegetation of this forest was first surveyed in 1965 and then again in
2004. The overstory tree community was similar between the two time periods with hemlock dominant in both samples. Conversely, seedlings,
saplings, and transgressives exhibited sharp declines in most species, including hemlock, which resulted in dissimilar community composition and
structure for these age classes between 1965 and 2004. Despite relative continuity in the dominance of mature hemlocks, low recruitment due to
overbrowsing makes the long-term persistence of hemlock in the old-growth forest of MRGP tenuous.
Bookmarks Related papers MentionsView impact
Journal of Zoology, 2006
Jaguars Panthera onca inhabiting tropical or subtropical evergreen moist forest have often been c... more Jaguars Panthera onca inhabiting tropical or subtropical evergreen moist forest have often been classified as opportunistic predators because they consume prey relative to its availability. However, these studies failed to address simultaneously the distribution of predator and prey through time and space, which may lead to an incomplete or erroneous understanding of jaguar foraging strategies. In this study, we reconstructed jaguar diet from scat, and used camera traps to investigate jaguar prey availability and the distribution of jaguar and its prey through space and time. We focused our examination of predator–prey temporal and spatial relations on forest infrastructure comprising man-made paths, small mammal trails, tapir Tapirus bairdi trail and trail-less, forested areas as they represent distinct habitats for prey selection. Overall, we observed high overlap between the prey used and available, suggestive of opportunistic foraging. However, jaguars exhibited selective tendencies in discriminating between larger prey. Jaguars used collared peccary Tayassu tajacu greater than its availability, while preying upon the equally abundant and similarly distributed white-lipped peccary Tayassu pecari and tapir less than predicted based upon availability. Armadillo Dasypus novemcinctus and paca Agouti paca, 56.6% of total consumption, were consumed relative to availability but exhibited low spatial overlap with jaguar. Armadillo and paca used trail-less, forested areas and small mammal trails not used by jaguar and were photographed more frequently at greater distances from man-made paths, major thoroughfares for jaguars. This study suggests that although forest jaguars use prey relative to its abundance, jaguars may rely on foraging strategies other than chance encounters for exploiting prey.
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Biotropica, 2006
The Cockscomb Basin Wildlife Sanctuary, Belize was established in 1986 following Rabinowitz and N... more The Cockscomb Basin Wildlife Sanctuary, Belize was established in 1986 following Rabinowitz and Nottingham's 1986 study on jaguar diet and distribution. In 2002, we reexamined jaguar diet following two decades of mitigated human hunting of jaguar prey. We observed high overlap between historical and current jaguar diet constructs. Nine-banded armadillo remained the most frequently consumed prey item. However, collared peccary consumption increased by nearly 20 percent while dietary breadth decreased by 60 percent presumably reflecting increased prey availability following reduced human hunting pressure.
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Northeast Wildlife, 2001
To effectively manage eastern chipmunk (Tamias striatus) populations in urban environments, an u... more To effectively manage eastern chipmunk (Tamias striatus) populations in
urban environments, an understanding of chipmunk habitat relationships is needed.
Although anecdotal information suggests that the distribution of chipmunks is
nonrandom in urban parks, no quantitative data are available, hindering conservation
efforts. Thus, our objective was to examine the importance of forest structure to
chipmunk distribution at the park and site (i.e., within-park) levels. During spring and
summer 2001, we live-trapped chipmunks in 5 New York City (NYC) parks and
quantified forest structure. Parks containing chipmunks had greater overstory and
understory tree size, and lower shrub stem, stump, and snag densities than parks without
chipmunks, with shrub stem densities and litter depth being of greatest importance.
Within parks containing chipmunks, increased overstory tree size and herbaceous ground
cover characterized sites with chipmunks, with overstory tree size being of primary
importance. Although other factors may play a role in chipmunk distributions, our results
indicate chipmunks in urban parks prefer mature forest with large trees, few stumps and
snags, an open shrub layer, and abundant herbaceous ground vegetation. Thus, habitat
management for chipmunks should focus on enhancing large mast-producing trees,
opening the shrub layer, and providing herbaceous ground and litter cover.
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Ecological Modelling, 2013
In the northern suburbs of NYC, land managers have begun implementing bow-only hunts to reduce o... more In the northern suburbs of NYC, land managers have begun implementing bow-only hunts to reduce
overabundant white-tailed deer (Odocoileus virginianus) herds in an effort to promote forest regeneration.
However, there have been no attempts to model the impact of bow hunting on deer population growth.
Using harvest statistics from the Mianus River Gorge Preserve in Westchester County, NY we simulated
the impact of bow hunting on a population of female deer exhibiting density-dependent growth and
explored a range of carrying capacities, immigration rates, and harvest intensities. Simulated bow hunting
(adult harvest
≥
1.8 females km−2) was capable of achieving deer densities believed necessary for forest
regeneration (2.9 females km−2) in closed populations where carrying capacity = 13.8 females km−2, representing
the lower end of deer overabundance. At this carrying capacity and low immigration rates,
the impact of bow hunting was more variable, producing population declines ranging from 20 to 70%
contingent on harvest rates. Hours per harvest increased rapidly as the deer population declined requiring
nearly 5 times the hourly effort as female density approached target levels. Sustaining harvests over
multiple decades, particularly as effort per deer harvest increases, is one of the biggest challenges facing
bow-only hunts. As controlled bow hunts are executed by volunteer sportsmen, reductions will be determined
by hunters’ capacity or willingness to increase effort and efficiency. Bow hunting will therefore
likely result in deer densities lower than historical peak values, yet higher than is currently assumed
necessary for forest regeneration.
Bookmarks Related papers MentionsView impact
Northeastern Naturalist, 2011
We characterized the landscape-level habitat use of Megascops asio (Eastern Screech Owl) in a su... more We characterized the landscape-level habitat use of Megascops asio (Eastern
Screech Owl) in a suburban/urban region of New York and Connecticut using citizenscience
methodologies and GIS-based land-use information. Volunteers sampled their
properties using call-playback surveys in the summers of 2009 and 2010. We modeled
detection and occupancy as functions of distance to forest and two coarse measures
of development. AICc-supported models were validated with an independent dataset
collected by trained professionals. Validated models indicated a negative association
between occupancy and percent forest cover or, similarly, a positive association with
percent impervious cover. When compared against the systematic dataset, models that
used forest cover as a predictor had the highest accuracy (kappa = 0.73 ± 0.18) in predicting
the occupancy observations in the systematic survey. After accounting for detection,
both datasets support similar owl-habitat patterns of predicting occupancy in developed
areas compared to highly rural. While there is likely a minimum amount of forest cover
and/or maximum level of urbanization that Screech Owls can tolerate, such limits appear
to be beyond the ranges sampled in this study. Future research that seeks to determine
this development limit should focus on very urbanized areas. The high accuracy of the
citizen-science models in predicting the systematic dataset indicates that volunteer-based
efforts can provide reliable data for wildlife studies.
Bookmarks Related papers MentionsView impact
Wildlife Society Bulletin, 2011
Jacobson et al.’s (1997) individual branch-antlered male (IBAM) method is a popular camera techn... more Jacobson et al.’s (1997) individual branch-antlered male (IBAM) method is a popular camera
technique for estimating white-tailed deer (Odocoileus virginianus) abundance. Demographic ratios are
estimated from raw photographic occurrences (RPO) of males, females, and fawns. Point abundance
estimates of each group are estimated by using said ratios to extrapolate from a count of uniquely identifiable
males. In 2009, using camera-trap data from the Mianus River Gorge Preserve (NY), we modified the IBAM
technique to 1) generate measures of uncertainty for parameter estimates via bootstrapping camera stations,
and 2) address the concern that RPO ratios may be biased if groups of animals differ in their probability of
being photographed (e.g., trap success [TS]). For each sex–age group, we evaluated RPO as a function of TS
using linear regression to generate photographic counts standardized by TS (standardized photographic
occurrences [SPO]). We generated estimates of sex–age ratios and abundances using both RPO and SPO. To
evaluate the accuracy of using SPO in conjunction with the IBAM method, we independently estimated the
abundance of a marked group of female deer using a Poisson log normal (PNE) mark–resight estimator.
Abundance estimates across sex–age classes were most similar between PNE and IBAM when SPO
demographic ratios were used. Owing to the greater TS of females, using SPO discounted the relative
abundance of females and, thus, lowered the female:male ratios and raised the fawn:female ratio. Uncertainty
was broad across all approaches, yet accounting for TS reduced the confounding variability owing to
differences in detection probability and generated more accurate parameter estimates.
Bookmarks Related papers MentionsView impact
Wildlife Society Bulletin, 2011
Over the last decade, wildlife professionals in the New York City (NY, USA) metropolitan area ha... more Over the last decade, wildlife professionals in the New York City (NY, USA) metropolitan area
have increasingly turned to controlled archery hunts to reduce overabundant suburban deer populations. The
success of these deer management programs (DMPs) depends on a willing pool of hunters motivated to meet
harvest goals. This requires maintaining hunter satisfaction both now, and in the future when successful herd
reduction will result in fewer opportunities for deer harvest. With the goal of providing local deer managers
with feedback from hunters partaking in DMPs, we used surveys designed to evaluate why members hunted,
why they joined DMPs, members’ views on deer management, and ultimately, their satisfaction with
controlled hunts. Members were primarily motivated to hunt by the chance to see wildlife, opportunities
for recreation, and a passion for archery. Most (71%) reported that their enjoyment had increased since first
joining a DMP and satisfaction was not linked to harvest opportunity or success. Nevertheless, we
documented several trends that threaten the long-term sustainability of DMPs. First, 78.2% of survey
respondents were over the age of 40, possibly suggesting fewer younger recruits into DMPs. Second, the
opportunity to hunt previously unhunted land, a transitory incentive, was the most common reason for
participating in DMPs. Third, respondents whose DMP doe harvest was limited by choosing to spend time
on private, non-DMP land were also more likely to have seen fewer deer on DMP lands (G-test ¼ 13.2,
df ¼ 4, P ¼ 0.01). This suggests that effort will decline as deer herds decline.
Bookmarks Related papers MentionsView impact
Insecta Mundi, 2011
The southern Appalachian millipeds Boraria stricta (Brölemann, 1896) and B. infesta (Chamberlin, ... more The southern Appalachian millipeds Boraria stricta (Brölemann, 1896) and B. infesta (Chamberlin,
1918) (Diplopoda: Polydesmida: Xystodesmidae) have become established in Westchester Co., New York, and
Hartford Co., Connecticut, respectively. Only three individuals are available for the latter, but B. stricta has
established a reproducing population in southern New York state. This species is also recorded from Bland Co.,
Virginia, in the Ridge and Valley Physiographic Province. Boraria profuga (Causey, 1955) comprises two allopatric
populations, one in Montgomery Co., Arkansas, and the other in Ouachita Parish, Louisiana. Distributional records
and gonopod drawings are presented for these species plus B. deturkiana (Causey, 1942).
Bookmarks Related papers MentionsView impact
Wildlife Biology in Practice, 2012
We evaluated the accuracy of a previously published model of coyote (Canis latrans) sightings in ... more We evaluated the accuracy of a previously published model of coyote (Canis latrans) sightings in suburban Westchester County, New York. This model was originally developed using citizen reports of coyote sightings to predict the probability of a human-coyote interaction based on proximity to habitat features. Because the data were obtained from surveys, researchers could not separate patterns of site occupancy by coyotes from possible patterns of detection by respondents. Nevertheless, the model could be an indicator of site occupancy within the suburban matrix. We sought to evaluate the predictive power of the human-coyote interaction model with data gathered via a more rigorous method. To build a set of validation sites, we surveyed 11 parks in Westchester County and one park in Bronx County, NY with camera traps between April and October of 2010. The probability of photographing a coyote in a single trap-night was 0.06 ± 0.12 and all sites had >0.9 probability of detecting a coyote at least once given the total trap-nights at each site. During validation, we also added four additional sites that had been surveyed by other researchers with camera traps as additional “present” sites. Predictions of coyote presence or absence based on the human-coyote interaction model for these 16 validation sites were compared to the observed survey results. The model, which contained distances to forest, grassland, and pooled medium and high development performed well in predicting the observed data (kappa = 0.75 ± 0.17, Area-Under-Curve of Receiver-Operator-Characteristic plots = 0.90). The model appears to sufficiently predict coyote occupancy in a suburban-urban landscape and will form the basis of for development of a more comprehensive model of coyote distribution in the New York City metropolitan area. Furthermore, its accuracy illustrates how citizen science can provide reliable estimates of wildlife-habitat patterns in urban areas.
Bookmarks Related papers MentionsView impact
Urban Habitats, 2009
Japanese stilt grass (Microstegium vimineum) is an invasive grass in the eastern and midwestern U... more Japanese stilt grass (Microstegium vimineum) is an invasive grass in the eastern and midwestern United States. It tolerates a wide range of light and moisture conditions and has readily replaced native herbaceous vegetation in many areas. Despite its detrimental effects, Japanese stilt grass does provide some benefit, serving as habitat for ground amphibians such as frogs and toads (anurans) in areas where populations of white-tailed deer (Odocoileus virginianus) have depleted native herbaceous cover. We investigated relative abundances of common anuran species both inside and outside of a stilt grass invasion front in a Northeastern mixed hardwood forest. We used pitfall trap arrays to sample anuran species during the summers of 2006 and 2007 and we captured four species: wood frog (Rana sylvatica); pickerel frog (Lithobates palustris); spring peeper (Pseudacris crucifer); and American toad (Bufo americanus). We captured more individuals from each of these species in stilt grass plots. Too few spring peepers were captured for analysis, so we modeled the captures of the three remaining species—wood frog, pickerel frog, and American toad—with negative binomial regression against stilt grass presence/absence, soil moisture, soil temperature, and relative humidity. We compared models containing these parameters using AIC (Akaike's Information Criterion), a common information criterion used in model selection. All three species selected stilt grass plots, but appeared to do so for different reasons. Pickerel and wood frogs seemed to select primarily areas of high soil moisture, which was consistently greater in stilt grass plots. American toads selected stilt grass areas and areas of high humidity, though humidity did not vary according to stilt grass presence or absence. For all three species, stilt grass seemed to provide habitat value beyond any causal or correlative relationship with microclimate. These results suggest that some invasive species of herbaceous cover provide alternative habitat for native wildlife in degraded communities. Managers need to consider the effect on wildlife when considering removal of invasives, particularly when there is little native habitat and when removal would be destructive.
Bookmarks Related papers MentionsView impact
Journal of Wildlife Management, 2010
The expansion of coyotes (Canis latrans) into the northeastern United States is a major challenge... more The expansion of coyotes (Canis latrans) into the northeastern United States is a major challenge to wildlife professionals,
especially in suburban and urban areas where reports of human–coyote interaction (HCI) are on the rise. To assist wildlife professionals in
identifying potential hot spots of interaction and homeowners in evaluating their risk of a backyard encounter, we used the techniques of citizen
science to build a landscape model of HCI for suburban residential properties in Westchester County, New York, USA. We distributed surveys
via school children (kindergarten to grade 12) as part of a voluntary class assignment, to maximize the number of homeowners participating in
our study and to provide learning experiences for students. Of 6,000 surveys distributed to schools, .1,500 students interviewed their parents
on whether a coyote had been seen or heard on their property from 2003 to 2006. Although surveys could not be distributed randomly owing to
the participatory process of individual schools, we did receive responses from across Westchester County, representing the spectrum from the
most rural to the most urban towns. Homeowners who encountered (i.e., seen or heard) a coyote on their property were on average 50% closer
to forest, 36% closer to grassland, and 66% farther from medium- to high-intensity development, complementing existing knowledge on urban
coyote habitat use. Our model seemed robust in predicting an independent set of coyote observations (r 5 0.88). Based on this model, we
generated a map describing the probability of HCI that can be used by both wildlife professionals and homeowners. Regarding the former, state
wildlife agencies could more precisely target education campaigns on how to live with coyotes where the possibility of HCI was greatest.
Homeowners, in turn, could evaluate their own risk and modify behaviors that would make their property less attractive to coyotes.
Furthermore, in creating a descriptive model of HCI from citizen-generated data, we demonstrated how citizen science can be a useful
exploratory tool, generating a wealth of data over a large geographic area in a short period, especially when the inquest is appropriate to
stakeholder participation in data collection.
Bookmarks Related papers MentionsView impact
Forest Ecology and Management, 2006
Eastern hemlock (Tsuga canadensis; hereafter hemlock) was once relatively common in the northeast... more Eastern hemlock (Tsuga canadensis; hereafter hemlock) was once relatively common in the northeastern United States. However, recent
disturbances – including exotic pests and white-tailed deer overpopulation – have exacerbated declines in hemlock forest in the 20th century. As a
previously undisturbed stand, the Mianus River Gorge Preserve (MRGP) provided an ideal site to investigate the potential impact of these factors
on the structure and composition of old-growth hemlock forests. The woody vegetation of this forest was first surveyed in 1965 and then again in
2004. The overstory tree community was similar between the two time periods with hemlock dominant in both samples. Conversely, seedlings,
saplings, and transgressives exhibited sharp declines in most species, including hemlock, which resulted in dissimilar community composition and
structure for these age classes between 1965 and 2004. Despite relative continuity in the dominance of mature hemlocks, low recruitment due to
overbrowsing makes the long-term persistence of hemlock in the old-growth forest of MRGP tenuous.
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Journal of Zoology, 2006
Jaguars Panthera onca inhabiting tropical or subtropical evergreen moist forest have often been c... more Jaguars Panthera onca inhabiting tropical or subtropical evergreen moist forest have often been classified as opportunistic predators because they consume prey relative to its availability. However, these studies failed to address simultaneously the distribution of predator and prey through time and space, which may lead to an incomplete or erroneous understanding of jaguar foraging strategies. In this study, we reconstructed jaguar diet from scat, and used camera traps to investigate jaguar prey availability and the distribution of jaguar and its prey through space and time. We focused our examination of predator–prey temporal and spatial relations on forest infrastructure comprising man-made paths, small mammal trails, tapir Tapirus bairdi trail and trail-less, forested areas as they represent distinct habitats for prey selection. Overall, we observed high overlap between the prey used and available, suggestive of opportunistic foraging. However, jaguars exhibited selective tendencies in discriminating between larger prey. Jaguars used collared peccary Tayassu tajacu greater than its availability, while preying upon the equally abundant and similarly distributed white-lipped peccary Tayassu pecari and tapir less than predicted based upon availability. Armadillo Dasypus novemcinctus and paca Agouti paca, 56.6% of total consumption, were consumed relative to availability but exhibited low spatial overlap with jaguar. Armadillo and paca used trail-less, forested areas and small mammal trails not used by jaguar and were photographed more frequently at greater distances from man-made paths, major thoroughfares for jaguars. This study suggests that although forest jaguars use prey relative to its abundance, jaguars may rely on foraging strategies other than chance encounters for exploiting prey.
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Biotropica, 2006
The Cockscomb Basin Wildlife Sanctuary, Belize was established in 1986 following Rabinowitz and N... more The Cockscomb Basin Wildlife Sanctuary, Belize was established in 1986 following Rabinowitz and Nottingham's 1986 study on jaguar diet and distribution. In 2002, we reexamined jaguar diet following two decades of mitigated human hunting of jaguar prey. We observed high overlap between historical and current jaguar diet constructs. Nine-banded armadillo remained the most frequently consumed prey item. However, collared peccary consumption increased by nearly 20 percent while dietary breadth decreased by 60 percent presumably reflecting increased prey availability following reduced human hunting pressure.
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Northeast Wildlife, 2001
To effectively manage eastern chipmunk (Tamias striatus) populations in urban environments, an u... more To effectively manage eastern chipmunk (Tamias striatus) populations in
urban environments, an understanding of chipmunk habitat relationships is needed.
Although anecdotal information suggests that the distribution of chipmunks is
nonrandom in urban parks, no quantitative data are available, hindering conservation
efforts. Thus, our objective was to examine the importance of forest structure to
chipmunk distribution at the park and site (i.e., within-park) levels. During spring and
summer 2001, we live-trapped chipmunks in 5 New York City (NYC) parks and
quantified forest structure. Parks containing chipmunks had greater overstory and
understory tree size, and lower shrub stem, stump, and snag densities than parks without
chipmunks, with shrub stem densities and litter depth being of greatest importance.
Within parks containing chipmunks, increased overstory tree size and herbaceous ground
cover characterized sites with chipmunks, with overstory tree size being of primary
importance. Although other factors may play a role in chipmunk distributions, our results
indicate chipmunks in urban parks prefer mature forest with large trees, few stumps and
snags, an open shrub layer, and abundant herbaceous ground vegetation. Thus, habitat
management for chipmunks should focus on enhancing large mast-producing trees,
opening the shrub layer, and providing herbaceous ground and litter cover.
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