Local winter deer density: Effects of forest structure and snow in a managed forest landscape

*Background/Questions/Methods*
White-tailed deer (_Odocoileus virginianus_) are a ‘keystone herbivore’ with the potential to cause tree regeneration failure and greatly affect vegetation dynamics, stand structure and ecological function of forests across eastern North America. In northern mixed conifer-hardwood forests, local winter-time deer populations are dependent on habitat characterized by patterns of forest cover that provide shelter from snow and cold temperatures (lowland conifer stands) in close proximity to winter food (deciduous hardwood stands). Stand structure may also influence winter spatial deer distribution. Consequently, modification of forest cover patterns and stand structure by timber harvesting will affect local spatial deer distributions, with potential ecological and economic consequences. Here, we ask if forest cover pattern and stand structure, and their interactions with snow depth, can explain winter deer density in the managed forests of the central Upper Peninsula of Michigan, USA. For each local winter deer density estimate (from fecal pellet counts) we calculate stand-level characteristics for surrounding ‘landscapes of influence’ of radius 200 m. For these data, and modeled snow depth estimates, we use multivariate techniques to produce predictive models and to identify the most important factors driving local deer densities across our 400,000 ha study area. 

*Results/Conclusions*
Distance to the nearest conifer stand consistently explains the most variance in univariate regression models. Deer densities are highest near lowland conifer stands in areas where mean hardwood tree diameter-at-breast-height is low. Multiple regression models including these factors explain 22% of variance in deer density and have up to a 65% chance of correctly ranking a site’s deer density (relative to other sites within our study area). We use model ensembles to produce maps of estimated deer density (and associated uncertainty) for a subset of our study area and show how managers might use these maps to aid co-management of deer and forest regeneration. Our results highlight the importance of local and regional factors (forest cover-type pattern, stand structure, climate) on winter white-tailed deer density in managed hardwood-conifer forests. Use of these results, and the simulation model being developed, will help identify management practices that can decrease deer impacts and ensure the ecological and economic sustainability of forests in which deer browse is proving problematic for tree regeneration.
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Toward quantification of the feasible potential of land-based carbon dioxide removal

Global climate-change overshoot scenarios, where warming exceeds Paris Agreement limits before being brought back down, are highly dependent on land-based carbon dioxide removal (CDR). In the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), such scenarios are supported by optimistic global assessments of the technical and economic potential for land-based CDR. However, a further type of potential—the ‘‘feasible’’ potential, which includes socio-cultural, environmental, and institutional factors—is noted in the AR6 but not quantified. Here, we set out research frameworks to work toward quantification of this feasible potential. We first argue that quantifying the feasible potential will substantiallyreduce current assessed CDR potential. Second, we demonstrate how transdisciplinary methods are improving understanding of feasibility constraints on land-based CDR. Third, we explore frameworks for synthesizing these advances during the next IPCC assessment process. We conclude that the research community should carefully consider the use of techno-economic CDR assessments in evidence for policymaker

A waterbody typology derived from catchment controls using self-organising maps

Multiple catchment controls contribute to the geomorphic functioning of river systems at the reach-level, yet only a limited number are usually considered by river scientists and managers. This study uses multiple morphometric, geological, climatic and anthropogenic catchment characteristics to produce a single national typology of catchment controls in England and Wales. Self-organising maps, a machine learning technique, are used to reduce the complexity of the GIS-derived characteristics to classify 4485 Water Framework Directive waterbodies into seven types. The waterbody typology is mapped across England and Wales, primarily reflecting an upland to lowland gradient in catchment controls and secondarily reflecting the heterogeneity of the catchment landscape. The seven waterbody types are evaluated using reach-level physical habitat indices (including measures of sediment size, flow, channel modification and diversity) extracted from River Habitat Survey data. Significant differences are found between each of the waterbody types for most habitat indices suggesting that the GIS-derived typology has functional application for reach-level habitats. This waterbody typology derived from catchment controls is a valuable tool for understanding catchment influences on physical habitats. It should prove useful for rapid assessment of catchment controls for river management, especially where regulatory compliance is based on reach-level monitoring

UK landscape ecology: trends and perspectives from the first 25 years of ialeUK

Context The 25th anniversary of the founding of the UK chapter of the International Association for Landscape Ecology (ialeUK) was marked in 2017. Objectives To assess trends in UK landscape ecology research over ialeUK’s first 25 years, to compare these trends to changes elsewhere in the world, and to consider how ialeUK can continue to support landscape ecology research and practice. Methods A database of conference abstracts was compiled and examined in combination with a questionnaire that surveyed existing and former active members of ialeUK. Results Across 1992–2017 we observe noticeable trends including the declining roles of statutory bodies, the development of the ecosystem services concept, and a decrease in use of empirical methods. Analysis of questionnaire results highlighted four key areas: Developing new researchers; Facilitating conferences for networking, learning and discussion; Linking policy with practice; and Driving the continued growth of landscape ecology as a discipline. Challenges were also noted, especially regarding the adoption of a wider understanding of landscape ecological principles in management. Conclusions Increases in qualitative research, decreases in studies explicitly examining connectivity/fragmentation and an absence of landscape genetics studies in the UK are seemingly distinct from US landscape ecology and elsewhere around the world, based on published accounts. ialeUK has had success in increasing the role of landscape ecology in policy and practice, but needs to continue to aim for improved collaboration with other landscape-related professional bodies and contributions to wider sustainability agendas

Modelling Human-Fire Interactions: Combining Alternative Perspectives and Approaches

Although it has long been recognised that human activities affect fire regimes, the interactions between humans and fire are complex, imperfectly understood, constantly evolving, and lacking any kind of integrative global framework. Many different approaches are used to study human-fire interactions, but in general they have arisen in different disciplinary contexts to address highly specific questions. Models of human-fire interactions range from conceptual local models to numerical global models. However, given that each type of model is highly selective about which aspects of human-fire interactions to include, the insights gained from these models are often limited and contradictory, which can make them a poor basis for developing fire-related policy and management practices. Here, we first review different approaches to modelling human-fire interactions and then discuss ways in which these different approaches could be synthesised to provide a more holistic approach to understanding human-fire interactions. We argue that the theory underpinning many types of models was developed using only limited amounts of data and that, in an increasingly data-rich world, it is important to re-examine model assumptions in a more systematic way. All of the models are designed to have practical outcomes but are necessarily simplifications of reality and as a result of differences in focus, scale and complexity, frequently yield radically different assessments of what might happen. We argue that it should be possible to combine the strengths and benefits of different types of model through enchaining the different models, for example from global down to local scales or vice versa. There are also opportunities for explicit coupling of different kinds of model, for example including agent-based representation of human actions in a global fire model. Finally, we stress the need for co-production of models to ensure that the resulting products serve the widest possible community

Wildfire Risk as a Socioecological Pathology

Wildfire risk in temperate forests has become a nearly intractable problem that can be characterized as a socioecological “pathology”: that is, a set of complex and problematic interactions among social and ecological systems across multiple spatial and temporal scales. Assessments of wildfire risk could benefit from recognizing and accounting for these interactions in terms of socioecological systems, also known as coupled natural and human systems (CNHS). We characterize the primary social and ecological dimensions of the wildfire risk pathology, paying particular attention to the governance system around wildfire risk, and suggest strategies to mitigate the pathology through innovative planning approaches, analytical tools, and policies. We caution that even with a clear understanding of the problem and possible solutions, the system by which human actors govern fire-prone forests may evolve incrementally in imperfect ways and can be expected to resist change even as we learn better ways to manage CNHS

BALB/c Mice Deficient in CD4+ T Cell IL-4Rα Expression Control Leishmania mexicana Load although Female but Not Male Mice Develop a Healer Phenotype

Immunologically intact BALB/c mice infected with Leishmania mexicana develop non-healing progressively growing lesions associated with a biased Th2 response while similarly infected IL-4Rα-deficient mice fail to develop lesions and develop a robust Th1 response. In order to determine the functional target(s) for IL-4/IL-13 inducing non-healing disease, the course of L. mexicana infection was monitored in mice lacking IL-4Rα expression in specific cellular compartments. A deficiency of IL-4Rα expression on macrophages/neutrophils (in LysMcreIL-4Rα−/lox animals) had minimal effect on the outcome of L. mexicana infection compared with control (IL-4Rα−/flox) mice. In contrast, CD4+ T cell specific (LckcreIL-4Rα−/lox) IL-4Rα−/− mice infected with L. mexicana developed small lesions, which subsequently healed in female mice, but persisted in adult male mice. While a strong Th1 response was manifest in both male and female CD4+ T cell specific IL-4Rα−/− mice infected with L. mexicana, induction of IL-4 was manifest in males but not females, independently of CD4+ T cell IL-4 responsiveness. Similar results were obtained using pan-T cell specific (iLckcreIL-4Rα−/lox) IL-4Rα−/− mice. Collectively these data demonstrate that upon infection with L. mexicana, initial lesion growth in BALB/c mice is dependent on non-T cell population(s) responsive to IL-4/IL-13 while progressive infection is dependent on CD4+ T cells responsive to IL-4

A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds

The Numeniini is a tribe of thirteen wader species (Scolopacidae, Charadriiformes) of which seven are near-threatened or globally threatened, including two critically endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian - Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species