Deer Culling Research Articles

Missing carcasses, lost nutrients: Quantifying nutrient losses from deer culling practices in Scotland

Abstract Deer management has become an integral part of ecosystem recovery efforts across the globe. Within Scotland, annual deer culls have been implemented to control deer browsing, with the carcasses most often removed from the landscape. Given that animal bodies concentrate large quantities of nutrients, this practice may deplete ecosystems of vital nutrients. We quantified the nitrogen, phosphorous and calcium losses from the removal of culled deer carcasses using nationwide statutory cull reports for four deer species in Scotland between 2010 and 2021. We estimate that annual losses from carcass removal over this period averaged 195,652 kg of nitrogen, 152,834 kg of phosphorus and 251,188 kg of calcium across Scotland. While both red and roe deer were culled at a much higher rate than the other two species red deer culls accounted for approximately 70% of the nutrients lost. Further, while large quantities of all three nutrients were removed from the landscape, calcium losses were particularly high. We then calculated nutrient losses within the three land classifications used in statutory cull reporting—agricultural areas, open range and woodlands—across Scotland's Deer Count Areas. Using data from the literature, we considered these losses in the context of other major environmental inputs and outputs within each land classification. Our results demonstrate that while open range lost more nutrients compared to the other two land classifications, culling resulted in high rates of phosphorus and calcium loss throughout all land classifications when compared to other environmental inputs. Practical implication. Our findings suggest that current practices of carcass removal are gradually stripping nutrients from the Scottish landscape, potentially undermining habitat recovery goals. While this study offers a preliminary, coarse scale summary of the issue, the way forward requires further study of local effects from carcass removal on nutrient pools and balancing deer management with habitat function through interwoven deer and nutrient management strategies.

Drastic changes in ground-dwelling beetle communities following high-intensity deer culling: insights from an island ecosystem.

The overabundance of large herbivores can have detrimental effects on the local environment due to overgrazing. Culling is a common management practice implemented globally that can effectively control herbivore populations and allow vegetation communities to recover. However, the broader indirect effects of culling large herbivores remain relatively unknown, particularly on insect species such as ground-dwelling beetles that perform key ecosystem processes such as decomposition. Here we undertook a preliminary investigation to determine how culling sika deer on an island in North Japan impacted ground-beetle community dynamics. We conducted pitfall trapping in July and September in 2012 (before culling) and again in 2019 (after culling). We compared beetle abundance and community composition within 4 beetle families (Carabidae, Scarabaeidae, Geotrupidae, and Silphidae), across seasons and culling treatments. We found each family responded differently to deer culling. Scarabaeidae displayed the greatest decline in abundance after culling. Silphidae also had reduced abundance but to a lesser extent compared to Scarabaeidae. Carabidae had both higher and lower abundance after culling, depending on the season. We found beetle community composition differed between culling and season, but seasonal variability was reduced after culling. Overall, the culling of large herbivores resulted in a reduction of ground-dwelling beetle populations, particularly necrophagous species dependent on dung and carrion for survival. Our preliminary research highlights the need for long-term and large-scale experiments to understand the indirect ecological implications of culling programs on ecosystem processes.

Specialist carabids in mixed montane forests are positively associated with biodiversity-oriented forestry and abundance of roe deer

The ongoing transition within forest management towards more biodiversity-oriented practices, such as close-to-nature forestry and retention forestry, may benefit forest fauna such as forest-specialized ground beetles (Coleoptera: Carabidae). However, it remains unclear how forest carabids are jointly affected by these practices in Central European montane forests, which host particularly sensitive, range-restricted carabid species, and where biodiversity-oriented forestry is widely applied. Moreover, roe deer (Capreolus capreolus), the most common large herbivore in these forests, is intensively managed to reduce browsing pressure, but it is yet unknown how this may affect carabids, alongside the effect of silviculture. On 66 1-ha plots in the Black Forest region of Germany, we sampled carabids with pitfall traps, measured roe deer abundances using camera trapping, and measured several structural variables directly related to close-to-nature and retention practices, as well as variables describing microclimate and landscape-level forest cover. We found that the carabid assemblage was dominated by forest specialists, with little influence from fragmentation of the surrounding forest. Higher broadleaf share (and canopy cover for montane specialists) was correlated with higher carabid activity-density. Increasing stand maturity (and lying deadwood volume for montane specialists), was correlated with higher species richness. Plots with higher roe deer abundances showed higher carabid richness and activity-density. Assemblage composition changed along the altitudinal gradient, and both richness and activity-density increased with elevation. Thus, carabid communities, including montane specialists and several species of conservation interest, stand to benefit from close-to-nature and retention practices, if applied throughout the altitude range of montane forests. Forest carabids may additionally profit from maintaining higher roe deer abundances, but further research is needed to understand this causal link, as well as to weigh the costs and benefits of deer culling for forest biodiversity.

Hunting of sika deer over six decades does not restore forest regeneration

Abstract High densities of native and introduced deer hamper the regeneration of temperate forests worldwide. Sport hunting is often the sole means of deer control, but whether it can restore forest regeneration remains uncertain. We assessed the potential to restore forest regeneration using unrestricted sport hunting alongside commercial harvesting and government‐funded culling of introduced sika deer (Cervus nippon) across a 594 km2 landscape in North Island, New Zealand. We used six decades of repeated measurements of forest regeneration and deer presence, alongside monitoring of tagged stems in a 20‐year paired exclosure experiment, to determine whether deer control restored regeneration. In our exclosure experiment, mountain beech (Fuscospora cliffortioides) seedling and sapling density, growth and survival were variable but consistently higher when deer were excluded by fencing. Sapling counts in unfenced plots were ≈3–10 times lower after 60 years of deer control compared with unfenced plots, before sika colonisation and other mountain beech forests without sika deer. This result suggests canopy replacement remains at risk despite government‐funded culling and encouragement of sport hunting. Individual‐based demographic models show that mountain beech is unlikely to regenerate following canopy gap formation in our study landscape unless deer impacts are reduced from current levels. These demographic models predicted present‐day forest regeneration far better than two widely used proxies of deer impact: plot‐based counts of saplings and estimates of deer densities from faecal pellet counts. Synthesis and applications. Here, we show that intensive culling beyond that achievable by sport hunting is needed to reduce deer densities enough to assure canopy regeneration. These interventions will be necessary in the many places worldwide where sport hunting is being relied upon to protect forests but appears to be failing. Given the controversy associated with deer culling, and the need for clear evidence to justify its implementation, we suggest managers could strengthen the evidence base for their interventions by collecting data to build demographic models.

Woodland expansion in the presence of deer: 30 years of evidence from the Cairngorms Connect landscape restoration partnership

Abstract Restoring native woodlands to areas where they have been lost is a key element for tackling the nature and climate crises. Natural regeneration offers the potential to achieve this cheaply and at scale, but browsing ungulates like deer can inhibit this or alter the pattern of regeneration. This issue is particularly pronounced in the Scottish Highlands, a heavily deforested region with high deer numbers. We describe the work of the 60,000 ha landscape restoration partnership, Cairngorms Connect, in speeding up natural woodland expansion. We use 30 years of regeneration monitoring to show a consistent, large‐scale expansion of native woodland, largely through natural regeneration alongside deer culling, without the use of fences. This was achieved across the partnership, despite differing management histories and land‐managing organisations (comprising two statutory agencies, one private landowner and one non‐governmental organisation). During peak periods of woodland expansion, the area of new woodland (i.e. exceeding 100 trees per hectare) increased by 1.2%, 1.7%, 2.7% and 6.0% annually in the four landholdings' regeneration zones, equating to a total of approximately 164 ha annually of new woodland. Natural regeneration is however patchy and hard to predict. Higher levels of management intervention may be needed to increase species that are rarer, more palatable or further from seed sources; we recommend long‐term field trials to inform this, such as those underway in Cairngorms Connect. Further research should develop techniques for remote sensing of woodland expansion, verified against field data and combined with the development of process‐based models to enable us to predict the outcomes of different management scenarios. Synthesis and applications. We show that collaborative deer management across multiple adjoining landholdings can achieve rapid landscape‐scale native woodland expansion with minimal need for planting or fencing. Our results show the power of monitoring regeneration directly, to inform deer management for an area. We demonstrate that by uniting over a shared vision, organisations with differing management approaches and histories can build understanding alongside landscape‐scale ecological restoration.

A Before‐After Control‐Impact experiment reveals that culling reduces the impacts of invasive deer on endangered peatlands

Abstract Invasive deer have undesirable impacts on native ecosystems. Culling is commonly used to reduce those impacts, but is expensive and sometimes controversial. It is therefore important to robustly assess how culling reduces the impacts of invasive deer. We conducted a Before‐After Control‐Impact (BACI) experiment to determine how culling affects the impacts of invasive sambar deer Cervus unicolor in an endangered alpine peatland ecosystem in south‐eastern Australia. We established two blocks, each with four 4300‐ha experimental units, in which two units were randomly assigned to a treatment of deer culling and the other two were non‐treatment areas. Sambar deer relative abundance (faecal pellet count) and three impacts (ground degradation, pugging intensity and water turbidity) in three peatland features (peatlands, natural pools and sambar deer wallows) were surveyed before and after culling was implemented. We used four metrics to quantify the culling intensity in each treatment unit: treatment versus non‐treatment, number of deer culled on each unit, deer culled within a 500‐m buffer of impact monitoring sites and local probability of use by the cullers (1‐ha grid). The effects of culling on deer abundance and impacts were estimated using Bayesian generalised linear mixed models. Our analysis revealed that the effect of culling differed between the two experimental blocks. In one block, culling reduced deer abundance and three impacts. In the other block, culling did not reduce deer abundance but reduced three impacts and increased two impacts. The effects of culling were generally stronger when culling was estimated using finer‐scale (500‐m) than coarser‐scale (experimental unit) culling metrics. Synthesis and applications. Our study provides experimental evidence that culling invasive sambar deer reduces some of their undesirable impacts on endangered peatlands. That not all impacts were reduced by culling suggests that some effects of invasive species are slow to recover or require higher culling intensities to be reversed.

Profiti gospodarenja srnećom divljači u lovištima središnje Srbije

The aim of this paper is to analyze the total breeding stock market in 2021/2022, an estimate of the value of the stock of this type of game, the culling value and income per 100 ha of total hunting areas of all hunting grounds in Central Serbia. This research covered the roe deer breeding stock in the hunting grounds of central Serbia. Based on the analysis, the directions and possibilities for increasing the income in all hunting areas of Serbia has been considered. The assessment of the value of the roe deer breeding stock was determined according to the Rulebook (Official Gazette, No. 18/19), while the income from roe deer culling was calculated using the market price list given by the Hunting Association of Serbia for 2021/2022. It was determined that the value of the male roe deer stock is 6.506.000 €, while the value of the female and offspring stock is approximately 3.615.000€. Total income of culled game in 2017/2018 was 480.626 €, while the income per 100 ha of the total area of all hunting areas is 9€. The highest total income is generated by the Central Hunting ground and it amounts to 191.785 €. In order to achieve a higher profit from the management of roe deer at the hunting grounds of central Serbia, it is necessary to completely fulfill the planned culling with an increased inclusion of roebucks that have higher trophy mass.

Highlighting the risk of environmental lead contamination for deer management in Australia

SummaryLead‐based bullets used to shoot deer typically fragment. These toxic fragments are a threat to wildlife scavengers and human consumers of venison. Awareness of this issue is widespread internationally but limited in Australia. The aim of this research was to characterise deer carcass contamination via bullet fragmentation associated with lead‐based and lead‐free ammunition in a deer culling program conducted in Australia. We used radiography (X‐rays) to study Hog Deer (Axis porcinus) shot in a professional ground‐based shooting program in Victoria, south‐eastern Australia. Our data captured 33 deer shot with frangible lead‐based bullets in 2021, and 21 deer shot with monolithic lead‐free (copper‐based) bullets from the same rifles in 2021–2022. For lead‐based bullets, the mean number of lead fragments per carcass ranged from seven to 629 (mean ± SD = 256 ± 169), mean fragment size was 1.2 mm2 (74% of fragments were <1.0 mm2) and the mean fragment coverage area (the smallest ellipse covering all fragments) was 325 cm2. Of these deer, 36% had metallic fragments in the ‘back strap’ (loin) muscles and 42% had metallic fragments in the shoulder muscles: meat cuts typically removed for human consumption. In contrast, for lead‐free bullets, the mean number of metallic fragments per carcass ranged from zero to four (0.5 ± 1.0), with only 29% of carcasses having any fragments, and no deer had metallic fragments in the loin or shoulder muscles. On the basis of these results, it is clear that lead‐based bullets used for shooting deer in Australia pose risks to wildlife scavengers, and to human consumers when used in hunting. Australian wildlife managers involved in mitigating deer impacts should strongly consider a timely transition to lead‐free bullets.

Do Feed Plants Provide Sufficient Sodium, Calcium and Magnesium to Sika Deer in Japan? An Analysis Using Global Plant Trait Data

Deficient minerals in overabundant populations could act as an attractant to cull sika deer (Cervus nippon). Because selective culling of female deer is reported to be effective in reducing sika deer populations, it is particularly important to clarify the differences in mineral requirements between males and females. Here, using global plant trait data and a published list of sika deer feed plants in Japan, we estimated whether feed plants provide sika deer sufficient sodium (Na), calcium (Ca) and magnesium (Mg), and compared the results between males and females. An analysis of 191 feed plant species suggested that feed plants can provide sufficient Mg, whereas sufficient Na and Ca is not always provided, especially when the intake is small or the deer large. Na deficiency was more intense for lactating females than males, suggesting that Na can be an effective attractant for selectively culling female deer. In summary, this study demonstrated that sika deer in Japan might require extra Na and Ca sources in addition to feed plants, and therefore these minerals could be useful for developing effective culling methods.

Escape Game: Responses of Northern White Cedar (Thuja occidentalis L.) to an Extreme Reduction in White-Tailed Deer (Odocoileus virginianus Zimmerman) Population

Northern white cedar (Thuja occidentalis L.) is a species of high ecological and economic value whose abundance has been declining since the pre-industrial period. It is an important element of white-tailed deer (Odocoileus virginianus Zimmerman) habitat, but its regeneration can be compromised by excessive browsing. This situation is especially critical in deeryards, where deer concentrate during winter. In 2018 and 2019, deer culling operations were carried out by the Ministry of Forests, Wildlife and Parks of Québec over 400 km2 in response to the occurrence of chronic wasting disease cases on a red deer farm. This operation offered an opportunity to look at how variations in deer pressure influence cedar regeneration and how cedar responds to a sudden reduction in browsing. We conducted regeneration surveys within and outside mapped deeryards both in the deer reduction zone and in a control zone. We performed dendrochronological analyses of cedar seedlings and saplings to quantify radial growth response to a reduction in browsing pressure. The results show that cedar basal area influences the abundance of small seedlings but that the effect of browsing becomes dominant for seedlings taller than 50 cm. Cedar growth responds to a reduction in browsing, but a two-year period was not sufficient to translate into changes in regeneration structure. The duration of the windows of opportunity at low browsing pressure required for cedar to reach a safe height remains to be determined. However, canopy openness had a significant influence on growth, suggesting that silvicultural measures could be taken to shorten the period of vulnerability to deer browsing.

Kinship analysis reveals low dispersal in a hog deer (Axis porcinus) population in Wilsons Promontory National Park, Australia

Context A wild population of non-native hog deer has established in the Gippsland region of Victoria, Australia, and there is particular concern about its impact on native vegetation in Wilsons Promontory National Park (WPNP). Since 2015, there has been annual culling of hog deer at WPNP to reduce deer abundances and impacts. Aims The aims of this study were to use a kinship approach based on genotyping to assess contemporary dispersal of hog deer across WPNP, by identifying close kin, to determine whether dispersal of deer into culled sites from unculled sites may affect the long-term success of management there. Differences in the dispersal of male and female hog deer were also investigated. Methods In total, 91 hog deer tissue samples were collected across WPNP and surrounding sites. Single nucleotide polymorphism (SNP) markers were sequenced, and a final dataset comprising 8275 SNPs was used for analysis. First-order, second-order, and intermediate relative pairs were identified, and the geographic distance between these pairs was assessed to determine inter-pair distances to infer dispersal. Spatial autocorrelation between male and female samples was evaluated to measure the effects of sex-biased dispersal. Key results Only seven second-order relative pairs were found across different sites, with a 30 km distance between the furthest pair observed. However, most inter-pair distances across sites were ~5–10 km. Analyses of sex-biased dispersal showed that movement by deer was not strongly influenced by one sex. Conclusions Although hog deer in WPNP are genetically similar, most relatives that were sampled were not widely dispersed. This suggests that there is limited dispersal of hog deer across this park. Implications Recolonisation of hog deer at culled sites via dispersal is likely to be infrequent in WPNP. Kinship analysis provides an effective method of assessing contemporary dispersal and could be applied to other species to assess fine-scale movement across landscapes.

Rapid increase in sensitive indicator plants concurrent with deer management in an oak forest landscape

AbstractWildlife managers are implementing programs to reduce abundant populations of large herbivores, such as white‐tailed deer (Odocoileus virginianus) in eastern North America, with renewed research interest in understanding these programs' ecological effects. To examine plant community change following culling of white‐tailed deer in oak (Quercus spp.) forests in Ohio, USA, we measured browse severity on tree seedlings and cover of 43 deer‐sensitive, native indicator plant species across 20 years spanning pre‐ (2002–2015) and post‐ (2016–2021) deer culling periods. After culling halved deer abundance from 16.7 deer/km2 to 8.6 deer/km2, browse patterns on tree seedlings reversed from most seedlings exhibiting browse damage to most being undamaged. Cover of deer‐sensitive indicator plants increased 7‐fold in the 6 years after deer culling. Five of 6 indicator plant groups (e.g., Liliaceae) and 32 of 43 indicator species (74%) increased in cover after deer culling. Rhizomatous, clonally reproducing and early flowering (May–Jun) species were generally most responsive. The rapid increase in deer‐sensitive plants after deer culling in our study is among the fastest and largest reported among eastern North American studies. The plant community resilience observed in this study could partly relate to the relatively short duration (~10 yr) that deer populations were elevated before culling began, allowing persistence of local plant regeneration potential. Deer culling enabled a moderate deer population to coexist with a rising sensitive plant population.

Impact of landcover composition and density of localized deer culling sites on chronic wasting disease prevalence

Chronic Wasting Disease (CWD), the prion disease of the Cervidae family, has been managed in Illinois deer since it was first detected in the Fall of 2002. Management uses a state-sponsored localized focus culling (LFC) program, implemented as close as possible to previously identified CWD-infected locations (TRSs (township/range/section)). We used hunter-harvest and LFC deer from 4621 and 435 unique TRSs, respectively, over 16 years of surveillance and management (2003–2017). We divided the study area into groups of TRSs with similar landcover types (SPLT) to assess CWD hunter-harvest prevalence at LFC and non-LFC sites by landcover composition. We also evaluate the importance of the month when LFC was implemented and determine whether the density of LFC sites or the total number of deer removed by LFC predicts hunter-harvest CWD prevalence. The percentage of CWD positive samples from hunters was lower than for LFC samples (for the study area and SPLTs). The probability of CWD increased by 5.24% for all the SPLT groups combined in the study area, by 4.6% from areas without an LFC nearby, and by 1.21% for areas with a prior LFC nearby. For all the TRS in the study area, low CWD odds (<1) in hunter-harvest deer were found in three SPLTs, in two SPLTs within TRSs with non-LFC, and five in five SPLTs within TRSs with LFC. The results suggest the importance of accounting for landcover composition to implement and sustain management in habitats with a higher risk of CWD. Our findings support that hunter-harvest alone cannot control CWD and the critical need for continued LFC intervention. For the whole study area—regardless of landcover composition—LFC in January was more important in decreasing hunter-harvest CWD prevalence than when LFC was conducted in March. However, the LFC conducted in January, February, and March were equally important when evaluating the month per habitat. Furthermore, the density of LFC sites in proximity to known infected areas is a better predictor of CWD than the number of deer removed by LFC, suggesting that increasing the density of LFC sites has a greater impact on CWD. The proximity of LFC to infected areas helps control CWD. Ultimately, landowners’ and hunters’ collaborations with the CWD surveillance and management programs are critical to protecting the Illinois wild deer herd; this study demonstrates their ongoing and valuable contributions to protecting this natural and public resource.

The Status and Swot Analysis of Roe Deer Population Management in the Hunting Grounds of Central Serbia

Summary The purpose of this study is to examine the status of roe deer population in the hunting grounds of Central Serbia, and perform a SWOT analysis of its management. The data used herein on the number of roe deer individuals and culling events were obtained from the Ministry of Agriculture, Forestry and Water Management - Forest Administration and the Statistical Office of the Republic of Serbia. Moreover, the Law on Game and Hunting was used for analysis purposes. The status of roe deer population in the hunting grounds of Serbia is quite unsatisfactory, depending on the geographical area and wildlife management practices. In 2021, a total of 86,755 individuals were recorded in the area of Central Serbia, which accounts for 97.54% of the optimal population. However, the number of roe deer in the individual hunting grounds of the Central and Eastern hunting areas was above the optimal density, whereas the number of roe deer accounted for 88.58% and 89.12% of the optimal density in the individual hunting grounds of the Southern and Western hunting areas, respectively. The largest number of individuals per unit area (km2) was recorded in the Eastern (2.06) and Belgrade (2.02) hunting areas, whereas the smallest number of individuals per unit area (km2) was recorded in the Southern (1.02) and Western (1.34) hunting areas. The following issues were identified as major impediments to the management of roe deer population in the hunting grounds considered: legislative and regulatory instruments, non-compliance and non-enforcement of a large number of regulations, roe deer monitoring issues, poor hunting ground control, inapplicability of certain regulations in the field of veterinary medicine, environmental protection, unresolved issues of trophy and game meat export, lack of strategic planning (namely the hunting development strategies of the Republic of Serbia), lack of deer habitat monitoring methodology and rating methodology, and unprofessional planning and development of hunting ground management plans. The SWOT analysis performed emphasized the strengths, weaknesses, opportunities and threats of roe deer population management in Serbia.

Evaluating the ability of a locally focused culling program in removing chronic wasting disease infected free-ranging white-tailed deer in Illinois, USA, 2003-2020.

In northern Illinois, chronic wasting disease (CWD) was first identified in free-ranging white-tailed deer (Odocoileus virginianus; hereafter referred to as "deer") in 2002. To reduce CWD transmission rates in Illinois, wildlife biologists have conducted locally focussed culling of deer since 2003 in areas where CWD has been detected. We used retrospective spatial, temporal and space-time scan statistical models to identify areas and periods where culling removed higher than expected numbers of CWD-positive deer. We included 490 Public Land Survey "sections" (∼2.59 km2 ) from 15 northern Illinois counties in which at least one deer tested positive for CWD between 2003 and 2020. A negative binomial regression model compared the proportion of CWD positive cases removed from sections with at least one CWD case detected in the previous years, "local area 1 (L1)," to the proportion of CWD cases in adjacent sections-L2, L3, and L4-designated by their increasing distance from L1. Of the 14,661 deer removed and tested via culling, 325 (2.22 %) were CWD-positive. A single temporal CWD cluster occurred in 2020. Three spatial clusters were identified, with a primary cluster located at the border of Boone and Winnebago counties. Four space-time clusters were identified with a primary cluster in the northern portion of the study area from 2003 to 2005 that overlapped with the spatial cluster. The proportion of CWD cases removed from L1 (3.92, 95% CI, 2.56-6.01) and L2 (2.32, 95% CI, 1.50-3.59) were significantly higher compared to L3. Focussing culling efforts on accessible properties closest to L1 areas results in more CWD-infected deer being removed, which highlights the value of collaborations among landowners, hunters, and wildlife management agencies to control CWD. Continuous evaluation and updating of the culling and surveillance programs are essential to mitigate the health burden of CWD on deer populations in Illinois.

Public perceptions of deer management in Scotland: the impact of place of residence, knowledge and demographic factors

ABSTRACT Deer have a prominent public and political profile in Scotland because of their iconic status, environmental and socio-economic impacts, and the long-running controversies surrounding their management. However, few studies have examined public perceptions of deer management. This article investigates whether rural and urban place of residence and other demographic factors are significant influences on public perceptions of deer management. A survey (n = 184) in rural and urban locations in Scotland explored public perceptions of deer management in contrasting localities. Place of residence, demographic information and self-reported knowledge levels were analysed to examine their impact on perceptions. Respondents generally agreed that deer management is necessary, with fencing and culling the first and second most preferred management options. Rural or urban place of residence had a limited influence on opinions of deer management, with engagement in land-based employment playing a more important role. Self-reported understanding of deer management was the most important factor in shaping opinions; those with greater knowledge were more likely to support deer culling. The findings suggest that improved public education concerning the need for deer management would be beneficial, increasing public understanding of management practices.

Delineating genetic management units of sambar deer (

Abstract Context Invasive species are major drivers of biodiversity loss, requiring management to reduce their ecological impacts. Population genetics can be applied to delineate management units, providing information that can help plan and improve control strategies. Aim The present study aims to use a genetic approach to test the existence of three previously proposed sambar deer populations in south-eastern Australia. In doing so, the study aims to delineate management units of sambar deer in south-eastern Australia. Methods Sambar deer DNA was sourced opportunistically from tissue samples and targeted scat collection. Samples were collected from three areas in Victoria, south-eastern Australia: Mt Cole (MC), French Island (FI) and eastern Victoria (EV). Contemporary population structure was assessed using a suite of 11 polymorphic microsatellite markers. The number of maternal sambar deer lineages in south-eastern Australia was investigated through sequencing of the mitochondrial (mt)DNA control region. Key results Three distinct genetic clusters were identified. Differentiation among inferred clusters was found to be high, with FST ranging from 0.24 between EV and FI clusters and 0.48 between MC and FI clusters. Two mtDNA haplotypes were identified; R.u1 was found throughout EV and FI, and R.u2 was unique to MC. DNA isolated from scats provided reliable data and proved critical for sampling areas where hunting and culling of deer are not generally undertaken. Conclusions Three genetically distinct sambar deer management units in south-eastern Australia are defined – MC, FI and EV. Sambar deer control strategies should be applied to each management unit independently. This may be difficult or infeasible for the EV management unit, which is large and geographically complex. Further research may help identify additional fine-scale genetic structure in EV, allowing smaller, more practicable management units to be identified. Implications Genetic data can be used to identify management units for invasive species, which will be critical for the development of future management strategies and improving control operations. The approach outlined here could also be applied to improve the management of other introduced deer species in south-eastern Australia.

Effects of culling white-tailed deer on tree regeneration and Microstegium vimineum, an invasive grass

Reduction of forest regeneration due to overbrowsing by white-tailed deer is a growing concern for land managers. Abundant deer can impede forest regeneration through direct predation on tree seedlings. Additionally high deer density can facilitate the establishment of a dense understory of browse tolerant plant species that shades seedlings and persists even in the absence of deer. In response to these challenges, land managers have sought to reduce deer herds to restore tree regeneration, but few studies have evaluated the effectiveness of this management. Our study took place in Catoctin Mountain Park, a US National Park Service unit with a history of high deer density. The park has been heavily invaded by Microstegium vimineum, an invasive grass that can completely cover the forest floor. Using permanent plots established prior to the start of deer management, we were able to assess the joint effects of deer culling and M. vimineum on tree seedling density. We found that tree seedling density increased in response to deer reductions. M. vimineum cover initially increased, but then decreased. Seedling densities were higher in plots with more M. vimineum cover, indicating that it did not form a recalcitrant understory that would suppress regeneration. However, eight years after deer management began, few tree seedlings were >30 cm tall, implying that it will be many years before they grow into the sapling stage. Our results indicate that deer culling can be an effective tool in restoring tree regeneration despite the presence of M. vimineum, but that success will require a long-term commitment.

LCA and wild animals: Results from wild deer culled in a northern Italy hunting district

Abstract Although the research of innovative and sustainable environmental alternatives to meat consumption is increasing, little attention has been given to hunting activity, which has traditionally provisioned food products from wild animals. Given this gap, the present study aims to quantify the environmental impacts of wild red deer culling (Cervus elaphus) through selective hunting in a mountainous Italian district, adopting a cradle-to-gate life cycle assessment (LCA) approach. Nine impact categories are evaluated using the International Reference Life Cycle Data System (ILCD) v1.09 impact assessment method, with climate change filling a special role. The results highlight that the long distances covered by the hunters to cull wild red deer is the hotspot of the supply chain representing almost 85% of the impact in every considered impact categories. Focusing on climate change, the outcomes show that the emissions of greenhouse gases (GHGs) per functional unit (4.85 kg CO2eq) are largely influenced by the hypothesis considering the wild red deer as an elementary flow entering the system and, thus, not including enteric methane emissions. In this case, the hunted red deer meat appears to be an environmentally sustainable alternative to conventional beef. The representativeness of the findings has to be increased both within the same species and in association with other wild ungulates (e.g., roe deer, wild boar or chamois) to better understand the potential role of traditionally hunted wild products in more sustainable diets.

Interventions to prevent Lyme disease in humans: A systematic review.

Lyme disease (LD) is an infection transferred to humans through bites from infected ticks. Surveillance indicates that the number of LD cases is increasing in the UK, therefore, improved knowledge about reducing transmission from ticks to humans is needed. Eighteen electronic databases were searched and additional web-based searching was conducted, to locate empirical research, published from 2002 onwards. Sixteen studies that evaluated five types of prevention intervention were included: personal protection (n = 4), domestic strategies (landscape modification and chemical pest control) (n = 3), education (n = 6), vaccination (n = 3), and deer-reduction programmes (n = 2). In general the quality of evidence was low. Results suggest that personal protection strategies, including the use of tick repellents and wearing of protective clothes, can prevent tick bites and reduce the incidence of LD among adults. Educational interventions were generally successful for improving adults' knowledge, behavioural beliefs (e.g., self-efficacy for performing tick checks) and preventative behaviour, but for children, the findings were mixed. For adults and children, knowledge changes did not typically translate into a lower incidence of LD. Whilst evidence on vaccination against LD is promising, too few studies were available to reach robust conclusions. There was no evidence of effectiveness for deer culling, and the evidence was inconclusive for applying acaricide (tick poison) to deer's ears and heads. Low-quality evidence suggests that personal protective strategies, that limit exposure to ticks, should continue to be recommended, as should education to encourage the adoption of personal protective strategies; further investigation of education interventions for children, vaccination and deer programmes is needed.