Too Many Hogs? A Review of Methods to Mitigate Impact by Wild Boar and Feral Hogs

Feral hogs (Sus scrofa) are among the most widely-distributed mammals in the world and have the highest reproductive output compared with other ungulates. Worldwide, feral hogs are increasing in range and numbers. Human–feral hog conflicts include impact on abundance and richness of plant and animal species, crop damage, predation on livestock, vehicle collisions, and disease transmission. We reviewed methods employed to mitigate the impact of feral hogs on human activities and discussed these methods in terms of effectiveness, feasibility, costs, and social acceptance. Traditional methods of control include trapping, angering, shooting, poisoning, and Judas hogs. Nonlethal methods of control include fertility control, fencing, repellents, diversionary feeding, and translocation.The review indicated that successful eradications of feral hogs from islands have been achieved by combining different control methods and by establishing post-eradication monitoring to ascertain that the eradication had been completed. Conversely, on the mainland and in countries where feral hogs have long been established, management of human–feral hog conflicts often relies on population size reduction through hunting and poisoning the animals or on exclusion fencing and diversionary feeding. In the majority of instances, population control is not based on previous knowledge of local densities or on predicted impact of control on population size. Based on these results, we propose a framework of criteria to guide decisions regarding the suitability of different options to manage human–feral hog conflicts in different contexts

Access to scientific literature by the conservation community

Access to the scientific literature is perceived to be a challenge to the biodiversity conservation community, but actual level of literature access relative to needs has never been assessed globally. We examined this question by surveying the constituency of the International Union for Conservation of Nature (IUCN) as a proxy for the conservation community, generating 2,285 responses. Of these respondents, ∼97% need to use the scientific literature in order to support their IUCN-related conservation work, with ∼50% needing to do so at least once per week. The crux of the survey revolved around the question, “How easy is it for you currently to obtain the scientific literature you need to carry out your IUCN-related work?” and revealed that roughly half (49%) of the respondents find it not easy or not at all easy to access scientific literature. We fitted a binary logistic regression model to explore factors predicting ease of literature access. Whether the respondent had institutional literature access (55% do) is the strongest predictor, with region (Western Europe, the United States, Canada, Australia and New Zealand) and sex (male) also significant predictors. Approximately 60% of respondents from Western Europe, the United States, Canada, Australia and New Zealand have institutional access compared to ∼50% in Asia and Latin America, and ∼40% in Eastern Europe and in Africa. Nevertheless, accessing free online material is a popular means of accessing literature for both those with and without institutional access. The four journals most frequently mentioned when asked which journal access would deliver the greatest improvements to the respondent’s IUCN-related work were Conservation Biology, Biological Conservation, Nature, and Science. The majority prefer to read journal articles on screen but books in hard copy. Overall, it is apparent that access to the literature is a challenge facing roughly half of the conservation community worldwide

The large-scale removal of mammalian invasive alien species in Northern Europe

Peer reviewedPublisher PD

Adapting Strategies to Maintain Efficiency During a Cull of Yellow-Legged Gulls

Increasing populations of yellow-legged gulls (Larus michahellis) in the Mediterranean have created conflicts with seabird conservation, migrating raptors, and humans. As a mitigation measure, gulls are routinely culled in the region. Previous studies of extended culls show that catch per unit effort declines over time through a combination of population reductions and avoidance behaviors developing within the remaining population. We countered these problems during a 4-year cull of yellow-legged gulls in Gibraltar by matching the type and mode of deployment of firearms in response to changes in gull distribution and behavior. We found that shotguns were effective when gulls mobbed operators near nesting areas, while rifles were more effective as gulls became wary and retreated farther from the operators. Changing the type of firearm enabled us to counter the expected rate of decline in culling efficiency throughout the project. We were most efficient in the first year of the project, killing gulls at a mean rate of 8.35 birds per man-hour. Although this declined to 4.83 by the third year, the adjustments that we made to the way firearms were deployed raised it to 6.4 in the fourth year despite a 79% decline in the observed total gull population over this period. We modelled the population data collected using a Leslie Matrix to evaluate the impact of management at the end of the culling period. The population declined at a greater rate than explained by the numbers actually culled, suggesting that the cull resulted in an additional disturbance, which triggered emigration at a rate of 35%, over and above the numbers culled

Using structured eradication feasibility assessment to prioritize the management of new and emerging invasive alien species in Europe

Prioritizing the management of invasive alien species (IAS) is of global importance and within Europe integral to the EU IAS regulation. To prioritize management effectively, the risks posed by IAS need to be assessed, but so too does the feasibility of their management. While the risk of IAS to the EU has been assessed, the feasibility of management has not. We assessed the feasibility of eradicating 60 new (not yet established) and 35 emerging (established with limited distribution) species that pose a threat to the EU, as identified by horizon scanning. The assessment was carried out by 34 experts in invasion management from across Europe, applying the Non‐Native Risk Management scheme to defined invasion scenarios and eradication strategies for each species, assessing the feasibility of eradication using seven key risk management criteria. Management priorities were identified by combining scores for risk (derived from horizon scanning) and feasibility of eradication. The results show eradication feasibility score and risk score were not correlated, indicating that risk management criteria evaluate different information than risk assessment. In all, 17 new species were identified as particularly high priorities for eradication should they establish in the future, whereas 14 emerging species were identified as priorities for eradication now. A number of species considered highest priority for eradication were terrestrial vertebrates, a group that has been the focus of a number of eradication attempts in Europe. However, eradication priorities also included a diverse range of other taxa (plants, invertebrates and fish) suggesting there is scope to broaden the taxonomic range of attempted eradication in Europe. We demonstrate that broad scale structured assessments of management feasibility can help prioritize IAS for management. Such frameworks are needed to support evidence‐based decision‐making

The eradication of invasive mammal species: can adaptive resource management fill the gaps in our knowledge?

Invasive alien species (IAS) threaten global biodiversity; they are the major cause of species extinction on offshore islands. Management of IAS requires data on the ecology of species in their new environment, how these species respond to management, and how these processes interact. Often, however, there is a paucity of information on key biological parameters that are critical to making management decisions. We sent a questionnaire to professionals and organizations managing invasive species and asked the respondents to prioritize a list of information they required to carry out eradication of invasive species. We analysed responses to assess the level of agreement among experts. Then, we compared them to a survey ranking available information in the peer-reviewed literature. We did this for 8 globally-important mammal species to identify gaps in available knowledge. We suggest that many of the shortfalls in knowledge can be best addressed through adaptive resource management (i.e., collecting data during the process of carrying out eradication itself, analyzing and processing these data, and using the information to make objective decisions that can be fed back into field operations). We recommend a modelling approach to enable the forecasting and testing of different scenarios when manipulative experimentation is impossible. As this process evolves, it should assist successful eradication of IAS on larger islands

Assessing Project Proposals Based on National and Global Tiger Action Plans: Lessons from the Integrated Tiger Habitat Conservation Programme (ITHCP)

Tigers play a crucial role in maintaining healthy ecosystems. Unfortunately, tigers are threatened by poaching, human–wildlife conflict, habitat loss, and more. In response to these threats, the conservation community pledged to double the worldwide wild tiger population by 2022 (known as TX2) at the “Tiger Summit” in St. Petersburg in 2010, and to track the progress of Tiger Range Countries. Between 2010 and 2022, the Global Tiger Recovery Programme was implemented. To accomplish this TX2 goal, each Tiger Range Country developed a National Tiger Action Plan (NTAP). The Integrated Tiger Habitat Conservation Programme (ITHCP) is a grant-making mechanism that focusses on a subsection of the Global Tiger Recovery Programme. It had twelve projects in six Tiger Range Countries during Phase 1 of the program. Evaluating the proposals of these projects is crucial for resource allocation. In this study, we assessed project proposals by evaluating how the proposed activities of all twelve ITHCP projects addressed their corresponding NTAPs, by comparing the plans against the proposals. A further comparison was undertaken using the Conservation Assured|Tiger Standards Lite, a site-based tiger conservation accreditation system. Overall, this study shows the importance of both global and national action plans and how comparing project activities with NTAP requirements can help address resource allocation needs to fill gaps in management. We conclude that projects should be designed to closely align with national action plans, best practice standards, and the activities of other projects in their landscape to maximize conservation outputs and impact. However, projects on their own are not enough to satisfy whole NTAPs

Assessing Project Proposals Based on National and Global Tiger Action Plans: Lessons from the Integrated Tiger Habitat Conservation Programme (ITHCP)

Tigers play a crucial role in maintaining healthy ecosystems. Unfortunately, tigers are threatened by poaching, human–wildlife conflict, habitat loss, and more. In response to these threats, the conservation community pledged to double the worldwide wild tiger population by 2022 (known as TX2) at the “Tiger Summit” in St. Petersburg in 2010, and to track the progress of Tiger Range Countries. Between 2010 and 2022, the Global Tiger Recovery Programme was implemented. To accomplish this TX2 goal, each Tiger Range Country developed a National Tiger Action Plan (NTAP). The Integrated Tiger Habitat Conservation Programme (ITHCP) is a grant-making mechanism that focusses on a subsection of the Global Tiger Recovery Programme. It had twelve projects in six Tiger Range Countries during Phase 1 of the program. Evaluating the proposals of these projects is crucial for resource allocation. In this study, we assessed project proposals by evaluating how the proposed activities of all twelve ITHCP projects addressed their corresponding NTAPs, by comparing the plans against the proposals. A further comparison was undertaken using the Conservation Assured|Tiger Standards Lite, a site-based tiger conservation accreditation system. Overall, this study shows the importance of both global and national action plans and how comparing project activities with NTAP requirements can help address resource allocation needs to fill gaps in management. We conclude that projects should be designed to closely align with national action plans, best practice standards, and the activities of other projects in their landscape to maximize conservation outputs and impact. However, projects on their own are not enough to satisfy whole NTAPs