Comparative hazard assessment for protected species in a fire-prone landscape

We conducted a comparative hazard assessment for 325,000 ha in a fire-prone area of southwest Oregon, USA. The landscape contains a variety of land ownerships, fire regimes, and management strategies. Our comparative hazard assessment evaluated the effects of two management strategies on crown fire potential and northern spotted owl (Strix occidentalis caurina) conservation: (1) no action, and (2) active manipulation of hazardous fuels. Model simulations indicated that active management of sites with high fire hazard was more favorable to spotted owl conservation over the long term (75 years) than no management, given our modeling assumptions. Early in the model simulation, young seral stages were mostly responsible for high fire hazard, and active management in young stands tended to perpetuate that hazard. Later in the simulation, older seral stages accounted for most of the high fire hazard and active management could be used to ameliorate that hazard. At any given time period, ⩽8% of the landscape was identified for treatment. Fire hazard fluctuated over time depending on vegetation regeneration, maturation, and response to treatments. Active management resulted in greater numbers of potential spotted owl territories in lower fire hazard conditions, particularly during later years of our simulation. Our results support the contention that short term risks to protected species from active management can be less than longer term risk of no management in fire-prone landscapes. Thus, a short term, risk averse strategy for protected species in fire-prone landscapes may not be the best long term alternative for conservation. We caution that this finding warrants landscape-level field evaluation and structured adaptive management and monitoring prior to broad scale adoption as environmental policy.Keywords: Comparative hazard assessment, Risk analysis, Spotted owls, Fire, Hazardous fuels management, OregonKeywords: Comparative hazard assessment, Risk analysis, Spotted owls, Fire, Hazardous fuels management, Orego

Effects of Wild Pig Disturbance on Forest Vegetation and Soils

In North America, wild pigs (Sus scrofa; feral pigs, feral swine, wild boars) are a widespread exotic species capable of creating large‐scale biotic and abiotic landscape perturbations. Quantification of wild pig environmental effects has been particularly problematic in northern climates, where they occur only recently as localized populations at low densities. Between 2016 and 2017, we assessed short‐term (within ~2 yrs of disturbance) effects of a low‐density wild pig population on forest features in the central Lower Peninsula of Michigan, USA. We identified 16 8‐ha sites using global positioning system locations from 7 radio‐collared wild pigs for sampling.Within each site, we conducted fine‐scale assessments at 81 plots and quantified potential disturbance by wild pigs. We defined disturbance as exposure of overturned soil, often resulting from rooting behavior by wild pigs.We quantified ground cover of plants within paired 1‐m2 frames at each plot, determined effects to tree regeneration using point‐centered quarter sampling, and collected soil cores from each plot. We observed less percent ground cover of native herbaceous plants and lower species diversity, particularly for plants with a coefficient of conservatism ≥5, in plots disturbed by wild pigs.We did not observe an increase in colonization of exotic plants following disturbance, though the observed prevalence of exotic plants was low. Wild pigs did not select for tree species when rooting, and we did not detect any differences in regeneration of light‐ and heavy‐seeded tree species between disturbed or undisturbed plots. Magnesium and ammonium content in soils were lower in disturbed plots, suggesting soil disturbance accelerated leaching of macronutrients, potentially altering nitrogen transformation. Our study suggested that disturbances by wild pigs, even at low densities, alters short‐term native herbaceous plant diversity and soil chemistry. Thus, small‐scale exclusion of wild pigs from vulnerable and rare plant communities may be warranted

Behavioral states in space and time: Understanding landscape use by an invasive mammal

Animal movement models can be used to understand species behavior and assist with implementation of management activities. We explored behavioral states of an invasive wild pig (Sus scrofa) population that recently colonized central Michigan, USA, 2014–2018. To quantify environmental factors related to wild pig movement ecology and spatio‐temporal landscape use, we predicted wild pig behavioral states relative to land cover type, landscape structure (i.e., edge and patch cohesion), and weather conditions. We used global positioning system (GPS)‐collars and monitored 8 wild pigs from 2014–2018. We fit local convex hulls and calculated movement metrics revealing 3 wild pig behavioral states (resting, exploratory, and relocating) and constructed a 3‐level model to predict behavioral state probabilities relative to biotic and abiotic conditions. Probabilities of exploratory and resting behaviors were higher nearer to riparian and open herbaceous cover types (oftentimes emergent marsh), indicating that these cover types provided security cover during activity and bedding. Hard mast cover types had a strong positive association with relocating behaviors. More cohesive patches of agriculture and shrub cover types were associated with higher probabilities of exploratory behaviors, while resting was more likely in continuous patches of agriculture (mostly mid‐summer corn). The probability of exploratory behaviors increased exponentially with warming ambient temperature. Our results may be used by managers to develop control strategies conducive to landscape and environmental conditions where the likelihood of encountering wild pigs is highest or targeting wild pigs when in a behavioral state most vulnerable to a particular removal technique

Complex ways in which landscape conditions and risks affect human attitudes towards wildlife

Negative interactions between humans and wildlife (i.e. those presenting risks to human security or private property) can trigger retaliation and potential human-wildlife conflict (HWC). The nature and strength of these human responses may depend on previous interactions with wildlife and can be shaped by landscape conditions. However, the ways in which previous experiences and landscape conditions interact to shape peoples’ attitudes towards wildlife are not well-understood. We conducted our study in Tsavo Conservation Area, Kenya, which experiences some of the highest rates of HWC documented in East Africa. We explored how previous experiences with wildlife and landscape conditions interact to inform the attitudes of people towards wildlife. We conducted semi-structured surveys among 331 households and fit an ordinal mixed-effects regression model to predict human attitudes to wildlife as a function of landscape conditions and previous interactions. Respondents indicated that baboons, elephants, and lions posed the greatest risks to human security and private property. Households experiencing risks from wildlife wanted wildlife populations to decrease, whereas households depending on grazing lands outside the study area wished to see wildlife increase. Our study demonstrates that human-wildlife interactions have important social and spatial contexts, and are not uniform across households in the same area owing to location of private property. Correspondingly, for interventions to be effective, we recommend considerations of local contexts and landscape conditions of communities.The Giraffe Conservation Foundation, Leiden Conservation Foundation, Wildlife Conservation Network, African Wildlife Foundation, and National Geographic Society.https://www.conservationandsociety.org.inam2023Centre for Wildlife Managemen

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Improving species occupancy estimation when sampling violates the closure assumption

Site occupancy models that account for imperfect detection of species are increasingly utilized in ecological research and wildlife monitoring. Occupancy models require replicate surveys to estimate detection probability over a time period where the occupancy status at sampled sites is assumed closed. Unlike mark – recapture models, few studies have examined how violations of closure can bias occupancy estimates. Our study design allowed us to diff erentiate among two processes that violate the closure assumption during a sampling season: 1) repeated destructive sampling events that result in either shortor long-term site avoidance by the target species and 2) sampling occurring over a time period during which non-random movements of the target species result in variable occupancy status. We used dynamic occupancy models to quantify the potential bias in occupancy estimation associated with these processes for a terrestrial salamander system. Our results provide strong evidence of a systematic decrease in salamander occupancy within a fi eld season. Chronic disturbance due to repeated searches of natural cover objects accelerated natural declines in species occurrence on the forest surface as summer progressed. We also observed a strong but temporary disturbance eff ect on salamander detection probability associated with repeated sampling within a 24-h. period. We generalized our fi ndings by conducting a simulation to evaluate how violations of closure can bias occupancy estimates when local extinction occurs within a sampling season. Our simulation study revealed general sensitivity of estimates from single-season occupancy models to violations of closure, with the strength and direction of bias varying between scenarios. Bias was minimal when extinction proba bility or the number of sample occasions was relatively low. Our research highlights the importance of addressing closure in occupancy studies and we provide multiple solutions, using both design- and model-based frameworks, for minimizing bias associated with non-random changes in occupancy and repeated sampling disturbances

Black Bear Exclusion Fences to Protect Mobile Apiaries

Demand for commercial bee (Apis mellifera) services recently has increased, resulting in greater use of mobile apiaries for crop pollination. When commercial apiaries are moved into areas occupied by black bears (Ursus americanus), conflicts between beekeepers and bears sometimes occur. Commercial pollination often involves moving apiaries among agricultural fields, and, thus, permanent fencing is not a viable option for reducing damage by bears. In 2010, we tested the effectiveness of 4 temporary electric fence designs for excluding black bears from bait sites in northern Michigan. We determined the effectiveness of each fence design by observing bear behavior obtained from 24-hour video surveillance. From \u3e433 minutes of bear–fence interactions (BFI), we recorded 168 BFIs in 73 visits by an estimated 15 bears. The only fence design deemed 100% effective at excluding bears consisted of 3 polytape strands charged with 5,000 V and spaced 0.58, 0.39, and 0.23 m from the ground, respectively. Proper fence construction and maintenance are critical elements of effectiveness, and we provide guidance on each. Our results demonstrate that low-cost temporary fencing can be an effective tool for excluding bears from localized sites, such as apiaries

Climate Factors Related to Localized Changes in Snowshoe Hare (Lepus americanus) Occupancy

Information on climate that influences snowshoe hares (Lepus americanus Erxleben, 1777) can inform adaptation strategies. We identified climate factors correlated with localized changes in occupancy of snowshoe hares in Michigan, USA. A change in occupancy occurred if a site (approximately 7.5 ha) knowingly occupied by hares sometime in the past became unoccupied. We used local ecological knowledge to map sites where hares historically occurred and to assign a year of last known occupancy. At 134 historically occupied sites, we conducted snow track surveys in 2013 to determine current occupancy status. We identified climate variables having relevance to hare population demographics and modeled the likelihood that those variables influenced current occupancy status. The top-ranking model included maximum temperature from May 15 â January 19; as maximum temperature increased the likelihood of a site becoming unoccupied increased. The second ranked model included total number of days with measurable snow on the ground; as days with snow on the ground decreased, the likelihood of a site becoming unoccupied increased. Our data indicated that site occupancy status of hares can be described by climate variables and that the southern edge of snowshoe hare distribution in Michigan shifted northward by ~45 km over the last 20 years.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author