Developing a Standard Protocol for Assessing Suburban Deer Impacts to Vegetation

White-tailed deer (Odocoileus virginianus} have been increasing dramatically in the eastern United States, with concomitant increases in impacts resulting from deer browsing and deer-vehicle collisions. In Ohio, the number of deer were estimated at near zero in 1940 to over 450,000 in 1995. We analyzed estimates of deer harvest and deer-vehicle collisions in 1995 for 88 counties in Ohio. These data were also related to county-level spatial data on the length of major highways, urban land, rural land, crop land, forest land, all land, and human population. The objectives of this study were to evaluate the spatial and temporal trends of white-tailed deer across Ohio and to relate these patterns to the formerly mentioned environmental and human variables.

Many states are striving to keep their deer population to a sustainable and controllable level while maximizing public safety. In Iowa, measures to control the deer population include annual deer hunts and special deer herd management plans in urban areas. While these plans may reduce the deer population, traffic safety in these areas has not been fully assessed. Using deer population data from the Iowa Department of Natural Resources and data on deer-vehicle crashes and deer carcass removals from the Iowa Department of Transportation, the authors examined the relationship between deer-vehicle collisions, deer density, and land use in three urban areas in Iowa that have deer management plans in place (Cedar Rapids, Dubuque, and Iowa City) over the period 2002 to 2007. First, a comparison of deer-vehicle crash counts and deer carcass removal counts was conducted at the county level. Further, the authors estimated econometric models to investigate the factors that influence the frequency and severity of deer-vehicle crashes in these zones. Overall, the number of deer carcasses removed on the primary roads in these counties was greater than the number of reported deer-vehicle crashes on those roads. These differences can be attributed to a number of reasons, including variability in data reporting and data collection practices. In addition, high rates of underreporting of crashes were found on major routes that carry high volumes of traffic. This study also showed that multiple factors affect deer-vehicle crashes and corresponding injury outcomes in urban management zones. The identified roadway and non-roadway factors could be useful for identifying locations on the transportation system that significantly impact deer species and safety and for determining appropriate countermeasures for mitigation. Efforts to reduce deer density adjacent to roads and developed land and to provide wider shoulders on undivided roads are recommended. Improving the consistency and accuracy of deer carcass and deer-vehicle collision data collection methods and practices is also desirable.

Many states are striving to keep their deer population to a sustainable and controllable level, while maximizing public safety. In Iowa, measures to control the deer population include annual deer hunts and special deer herd management plans in urban areas. While these plans may in effect reduce the deer population, traffic safety in these areas has not been fully assessed. Using deer population data from the Iowa Department of Natural Resources and data on deer-vehicle crashes and deer carcass removals from the Iowa Department of Transportation, we examine the relationship between deer-vehicle collisions, deer density, and land use in select urban deer management zones in Iowa. Further, we estimate models to investigate the factors that influence the frequency and severity of deer-vehicle crashes in these zones. The estimation results showed that multiple factors affect deer-vehicle crashes and corresponding injury outcomes in urban management zones. The identified roadway and non-roadway factors could be useful for identifying locations on the transportation system that significantly impact deer species and safety, and determining appropriate countermeasures for mitigation.

Abstract: High densities of white-tailed deer (Odocoileus virginianus) are believed to cause broad-scale forest regeneration failure and loss of plant diversity. But, the empirical basis for such presumptions is limited. We, therefore, conducted a survey in western Connecticut, USA, woodlots to examine how spatial variation in deer densities influences variation in impacts on plant species abundance, identity and diversity, and tree regeneration. We also used a Geographic Information System to quantify trends between land-cover type and deer density. Deer density was not correlated with any vegetation or land use variable. This suggests that deer density is not a leading factor determining variation in vegetation impacts across western Connecticut.

Hunting has been the primary white-tailed deer (Odocoileus virginianus) management tool for decades. Regulated hunting has been effective at meeting management objectives in rural areas, but typical logistical constraints placed on hunting in residential and urban areas can cause deer to become overabundant and incompatible with other societal interests. Deer-vehicle collisions, tick-associated diseases, and damage to residential landscape plantings are the primary reasons for implementing lethal management programs, often with objectives of <10 deer/km 2 . There are limited data demonstrating that hunting alone in suburban landscapes can reduce densities sufficiently to result in adequate conflict resolutions or a corresponding density objective for deer. We present data from 3 controlled hunting programs in New Jersey and one in Pennsylvania, USA. Annual or periodic population estimates were conducted using aerial counts and road- based distance sampling to assess trends. Initial populations, some of which were previously subjected to regulated unorganized hunting, ranged from approximately 30-80 deer/km 2 . From 3 years to 10 years of traditional hunting, along with organized hunting and liberalized regulations, resulted in an estimated 17- 18 deer/km 2 at each location. These projects clearly demonstrate that a reduction in local deer densities using regulated hunting can be achieved. However, the sole use of existing regulated hunting techniques in suburban areas appears insufficient to maintain deer densities <17 deer/km 2 where deer are not limited by severe winter weather. Additional measures, such as sharpshooting or other strategic adjustments to regulations and policies, may be needed if long-term deer-management objectives are much below this level. 2012 The Wildlife Society.

Context For management decisions that require accurate and precise estimates of large mammal population numbers, aerial surveys are considered reliable despite their cost. However, aerial surveys may still suffer from underestimation because of undetected animals and low precision as a result of inefficient sampling designs. Aims We assess detection of two species of deer in prairie-parkland communities of western Canada and evaluate a suite of survey design features for improving the accuracy and precision of population estimates from aerial surveys. Methods Modelling detection of deer was based on 100 sightability trials involving 54 radio-collared white-tailed and 46 mule deer. We used empirical survey data to simulate surveys under three alternative stratification approaches, schemes for grouping strata, and allocations of survey effort and compared the precision and accuracy of the resulting population estimates. Key results We observed deer in 83 of the 100 trials, with detection decreasing with small group size, reduced deer activity, low snow cover, high forest cover and observer fatigue. Survey precision and accuracy were highest when stratification was based on natural breaks, calculated via Jenks optimisation, in the values of resource-selection function (RSF), although improvement was less pronounced for estimates of mule deer abundance. Optimal or equal allocation of sampling effort among strata outperformed proportional allocation of sampling effort. Use of RSF for stratification reduced the coefficient of variation (CV) in estimates of deer numbers from 38% to 23% for white-tailed deer and from 33% to 27% for mule deer compared with past approaches. Conclusions Stratification based on RSF values improved precision of deer surveys the most; however, using even simple measures related to habitat selection can improve population estimates. Where deer are highly aggregated, reliably recording all variables needed to implement sightability models can prove problematic; however, survey detection adjustments are nevertheless important to account for the relatively small, but still significant, proportion of missed animals in open prairie–parkland environments. Implications Field experiments to assess aerial survey design are impractical because of cost. We illustrate how simulated surveys using empirical data can be useful to evaluate alternative survey designs to improve population estimates in a region when high accuracy or precision are needed to address management questions or to calibrate more cost-effective approaches.

Several wildlife biologists have developed models of habitat suitability for white-tailed deer (Odocoileus virginianus). Although these analyses have provided insight into factors affecting deer density and distribution over large scales, no studies have modeled habitat use of deer in exurban landscapes. We modeled habitat similarity to areas used most intensively by deer in exurban Carbondale, Illinois, USA, during the fawning (15 May–31 Jul) and winter season (15 Dec–15 Mar). We used >15,000 locations from 20 Global Positioning System–collared female deer tracked during 2003–2005, habitat variables, and the Penrose distance statistic for modeling. A positive correlation with number of dwellings (r = 0.45) and coefficient of variation of forest area (r = 0.16) indicated deer avoidance of areas with increased number of dwellings and variation in forest area during the fawning season. Deer decreased winter use of areas as the diversity of land-cover types (r = 0.64), variation in forest patch size (r = 0.40), and variation of grassland patch size (r = 0.18) increased. Winter habitat use of an area increased as size of forest patch area increased (r = −0.30). This model can be used by wildlife managers to better understand potential deer–human encounters and deer use of the landscape. Alternatively, wildlife managers may use the model to target areas for traditional harvest management or deer removal operations. © 2011 The Wildlife Society.

Context Although ~3% of white-tailed deer are killed on roads each year, no previous study has tested for an effect of roads on deer abundance. This is difficult to do because road density is generally negatively correlated with deer habitat availability. Aims Our goal was to determine whether roads affect deer abundance. Methods First, we used an existing dataset from Pennsylvania, USA, to determine a range of paved road densities representing a significant range in deer per capita mortality. We then conducted a field study in eastern Ontario, Canada, with sample sites for relative deer abundance selected such that (1) road density in the surrounding landscapes varied over this same range, and (2) there were low correlations across landscapes between road density and deer habitat availability. The latter allowed us to isolate the effects of roads from the effects of habitat on deer abundance. We indexed relative deer abundance using a combination of pellet samples and track counts. Key results Unexpectedly, we observed a positive relationship between relative deer abundance and paved road density. Conclusions We speculate that this positive relationship is due to (1) reduced deer predation and/or perceived predation risk and/or hunting pressure in landscapes with higher road density and/or (2) provision of a resource or service by roads, the benefits of which outweigh the road mortality. Implications We found no evidence that road mortality places deer populations at risk of decline, at least over the range of road density values in our study. Therefore we conclude that road mortality is not a conservation concern for white-tailed deer in ecological contexts similar to our study areas.

Firearms hunting often is limited as a deer (Odocoileus spp.) management tool in urban and suburban areas due to firearms discharge ordinances, restrictive hunting laws, or public perception about firearms safety. Many states use bowhunters to manage overabundant deer populations in urban-suburban areas. Little information exists on the effectiveness of bowhunting as a deer management tool in developed areas. Our objectives were to evaluate the potential for bowhunting to manage deer populations in urban-suburban areas and identify important variables influencing hunt effectiveness. We estimated deer population size and herd composition using aerial deer surveys and spotlight counts. Nonhunting mortality was determined from radiotelemetry data. We mailed a 9-page survey to bowhunters who hunted in a residential community with high deer densities to determine harvest rates, hunter success rates, willingness to harvest additional antlerless deer, and interest in employing aggressive deer management strategies. Of 159 surveys mailed, 71% were completed and returned. We conducted model simulations using Program STELLA® (High Performance Systems Inc., Lebanon, N.H.) to determine which management strategies would contribute most to stabilizing deer population growth. Sunday hunting provided 41% fewer hunting days, yet was more effective at reducing deer population growth than a January extension. Harvesting antlerless deer that hunters were passing up had the greatest relative effect in reducing deer population size. Incentive programs for hunters to harvest antlerless deer are needed. Combining multiple hunt strategies (i.e., January and Sunday hunting) may be more effective than implementing individual hunt strategies. A special crossbow season outside the existing archery season may be an effective deer management tool in urban areas.

The problem of highway accidents involving animals is a nationwide and worldwide concern. In Michigan, property damage to vehicles, human injuries and fatalities, and potential reductions of local deer populations result from vehicle collisions involving white-tailed deer (Odocoileus virginianus). During 1997, Michigan had 65,451 reported deer-vehicle crashes. This is a 52.7% rise from 42,868 deer-vehicle collisions in 1988, according to Michigan State Police Crash Statistics. Kent County has had a consistently higher number of deer accidents than any other county in Michigan, with 2,035 in 1997. To address this problem, the Kent County Deer-Vehicle Accident Reduction Study was undertaken. The study is using an ecological landscape perspective to investigate the interface of human population density and activity with deer population density and activity. Used in conjunction with educational efforts and speed reduction advisories, novel signs were placed in controlled test sites to study their effectiveness in changing driver behavior, and wildlife reflectors were implemented to test their effectiveness in changing deer behavior. Designing successful accident reduction techniques requires understanding deer and human movement patterns and behaviors. Interactions between people and white-tailed deer are increasing in Kent County as populations of both deer and humans are on the rise. As humans move into historic deer habitat and deer invade human-dominated landscapes, conflicts are more likely to occur. Using the information gathered from the analysis and synthesis of data, this study will document the effectiveness of all measures implemented during this study period and the pioneering efforts of Kent County as a model for other areas in addressing the problem of deer-vehicle collisions.

We conducted a statewide assessment of habitat suitability for white-tailed deer (Odocoileus virginianus) in Arkansas. We created a habitat suitability index (HSI) model that could be used with satellite imagery for habitat assessment based on life requisites for food and cover. The food and cover life-requisite equations included a vegetation-diversity modifier and distance modifiers to consider the proximity of potentially available resources. We tested model results against indices of relative population abundance and nutritional condition of deer at the county level. The original statewide model accounted for 45% and 23% of variation in abundance and nutritional condition indices, respectively. We adjusted the models to maximize fit with the population indices. The adjusted statewide HSI models accounted for 66% and 52% of variation in population abundance and nutritional condition indices, respectively. Separate models adjusted for each of the 4 physiographic regions of Arkansas were able to account for up to 76% of variation in relative abundance of deer. Landscape models of habitat suitability were most successful in the Gulf region, where large-scale commercial forests dominate, providing relatively equal habitat suitability across the landscape. Models were least successful in the Delta region, where the conversion to agriculture has fragmented habitat and suitability varied widely. Improvements in quality and resolution of population data and greater accuracy of classification of cover types, such as shrub communities, would allow greater understanding of the landscape-level features that are important indicators of habitat quality.

Korean water deer (Hydropotes inermis argyropus) is an endemic subspecies and one of the common species in Korea. However, deer have been threatened by human activities, which have resulted in the population decrease. To conserve and manage their populations, understanding Korean water deer’s habitat characteristics, which depend on the structure of the landscape, and identifying the relationship between those would be a key component. Our main aim was first to make landcover maps from remote sensing imagery, and to determine some habitat metrics for Korean water deer at two different home range scales (25 ha and 100 ha), and finally to compare them between habitat and non-habitat of the Korean water deer. This study analyzed spatial patterns at two scales in the Chungnam province environment by using the PCA-ECHO classification technique based on Landsat ETM+ remote sensing data (2001) and 19 habitat metrics. Study results show that habitat metrics for forest and open areas are more obviously distinguished within a 25 ha home range scales. Especially, more continuous and less fragmented forest patches and open area patches with a high edge density and connectivity were the main characteristics of Korean water deer’s habitat. As a part of habitat management, these results could be used as a good proxy for assessing the habitat quality of Korean water deer.

Mule deer populations in central Oregon are in decline, largely because of habitat loss. Several factors are likely contributors. Encroaching juniper and invasive cheatgrass are replacing deer forage with high nutritional value, such as bitterbrush and sagebrush. Fire suppression and reduced timber harvests mean fewer acres of early successional forest, which also offer forage opportunities. Human development, including homes and roads, is another factor. It is this one that scientists with the Pacific Northwest Research Station and their collaborators investigated in a recent study. As part of an interagency assessment of the ecological effects of resort development near Bend, Oregon, researchers examined recent and potential development rates and patterns and evaluated their impact on mule deer winter range. They found that residential development in central Oregon is upsetting traditional migratory patterns, reducing available habitat, and possibly increasing stress for mule deer. Many herds of mule deer spend the summer in the Cascade Range and move to lower elevations during the winter. An increasing number of buildings, vehicle traffic, fencing, and other obstacles that accompany human land use are making it difficult for mule deer to access and use their winter habitat. The study provides valuable information for civic leaders, land use planners, and land managers to use in weighing the ecological impact of various land use decisions in central Oregon.

Author(s): D’Angelo, Gino J.; Wenner, Willard L.; Keegan, Marian S. | Abstract: Hemlock Farms Community Association (HFCA) is a g4,500-acre private, gated community located in Pike County, Pennsylvania, established in the 1960s. During our study, 3,150 homes existed in HFCA, with 400 more homes expected to be built in the future. In recent years, the community took proactive steps to coexist with white-tailed deer in the community. Residents were fully involved in deer management decision making early in the process. Through the Pennsylvania Game Commission Deer Management Assistance Program, HFCA has allowed hunting by residents in undeveloped areas of the community to assist in reducing and maintaining deer densities. Non-lethal techniques to prevent browsing of the forest understory and landscape vegetation by deerother than fencingwere ineffective. U.S. Department of Agriculture Wildlife Services was consulted in 2005 by HFCA to initiate an integrated white-tailed deer damage management program to reduce damage to forest regeneration and landscaping, and to protect human health and safety. In October 2005, we began lethal deer removal via sharpshooting to reduce the deer population to 10 deer per square mile of forested habitat (50 deer) from an estimated =125 deer per square mile of forested habitat. By winter 2009-2010, we removed a total of 830 deer, bringing the population within the management goals of the community. The forest understory rebounded, deer-vehicle collisions were reduced to an annual level of near zero. Physiological indices suggested that the health of deer improved as population densities were decreased. Residents voted annually on a referendum to continue culling of deer. Therefore, monitoring of the deer population and education of residents will remain important components of the deer management regime.

With the rise in deer-vehicle collisions across the United States, the associated costs also have risen. Increasingly, however, researchers are learning that these collisions are not a random phenomena but follow a systematic pattern. Building on this insight, we explored the role of county characteristics in infl uencing the pattern and incidence of white-tailed deer- (Odocoileus virginianus) related auto collisions. Using county level data from 1994 to 2003 in Alabama, we tested several data models with the above mentioned factors as covariates. Our results showed that county characteristics, such as (1) having a deer population density (≥31/km 2 ), (2) being part of a metropolitan statistical area, (3) having a high proportion of pasture, urban and other land relative to woodland, and (4) having greater vehicle density per road km were more likely to increase the odds of deer-vehicle collisions. In contrast, high proportion of cropland relative to woodland, and wildlife management tools, such as increase in hunting license sales, and high deer bag limits, reduced the frequency of deer-vehicle collisions. These fi ndings suggested that urban planners need to consider the impact of urban development and infrastructure activities on deer habitat and densities, and how wildlife management strategies (e.g., judicious manipulation of bag limits and ways to promote hunting license sales) can be used along with other mitigation techniques to reduce deer-vehicle collisions.

• AVID detected differences in seedling growth inside vs. outside of deer fences. • Sugar maple and red oak seedlings grew 3.4 times faster in fenced plots. • Deer impacts to forest regeneration were widespread in stands across NYS. Extensive deer browsing threatens the ability of many forests in the northeastern United States to regenerate and sustain their biodiversity. To reliably assess whether deer are reducing the regeneration of key tree species valued for timber and wildlife, we developed a rapid field protocol for A ssessing V egetation I mpacts from D eer (AVID, http://AVIDdeer.com ). AVID is a method for foresters, landowners, volunteers, and others to measure the effect of deer browsing on seedling growth. Our objectives were to: 1. Determine if the AVID method could detect differences in growth rates for protected (fenced) and unprotected seedlings, 2. Evaluate AVID’s usefulness as a regeneration monitoring tool for citizen-science engagement, and 3. Compare and contrast the relative strengths and weaknesses of common methods for measuring deer impacts to vegetation. We compared fenced and unfenced plots at 10 research sites in New York State to validate the sensitivity of AVID for detecting deer impacts to seedling growth. Tagged seedlings were measured annually for height growth in replicated plots. Deer reduced average seedling height growth of palatable species several fold at these sites often in combination with the effects of site and year. From 2016 through 2020, we conducted 59 AVID training events with 1,399 participants including landowners, students, educators, naturalists, resource management professionals, and land trust staff. Volunteers established plots at 83 sites in 24 New York counties demonstrating that AVID provides a valued citizen-science approach for both teaching people and assessing deer impacts to forest regeneration. Once volunteers consistently monitor a statistically valid number of plots for several years, the New York’s Department of Environmental Conservation intends to use AVID data to inform deer management decisions.