Evidence of a spatial auto‐correlation in the browsing level of four major European tree species

1. The contribution of spatial processes to the spatial patterns of ecological systems is widely recognized, but spatial patterns in the ecology of plant‐herbivore interactions have rarely been investigated quantitatively owing to limited budget and time associated with ecological research. Studies of the level of browsing on various tree species reported either no spatial auto‐correlation or a small effect size. Further, the effects of disturbance events, such as hurricanes, which create large forest openings on spatial patterns of herbivory are not well understood.
2. In this study, we used forest inventory data obtained from the federal state of Baden‐Württemberg (Southern Germany) between 2001 and 2009 (grid size: 100 × 200 m) and thus, after hurricane Lothar struck Southern Germany in 1999. We investigated whether the browsing level of trees (height ≤ 130 cm) in one location is independent of that of the neighborhood.
3. Our analyses of 1,758,622 saplings (187.632 sampling units) of oak (Quercus), fir (Abies), spruce (Picea), and beech (Fagus) revealed that the browsing level is characterized by a short distance spatial auto‐correlation.
4. The application of indicator variables based on browsed saplings should account for the spatial pattern as the latter may affect the results and therefore also the conclusions of the analysis.

     

Linking alternative food sources to winter habitat selection of herbivores in overbrowsed landscapes

During winter, ungulates in boreal forests must cope with high energetic costs related to locomotion in deep snow and reduced forage abundance and quality. At high density, ungulates face additional constraints, because heavy browsing reduces availability of woody browse, the main source of forage during winter. Under these severe conditions, large herbivores might forage on alternative food sources likely independent of browsing pressure, such as litterfall or windblown trees. We investigated the influence of alternative food sources on winter habitat selection, by studying female white-tailed deer (Odocoileus virginianus) living in 2 landscapes with contrasted browse abundance, recently logged and regenerated landscapes, in a population at high density and on a large island free of predators. We fitted 21 female white-tailed deer with Global Positioning System (GPS) collars and delineated winter home ranges and core areas. We measured snow conditions in different habitat categories and sampled vegetation in the core areas and in the rest of the home ranges to determine how forage abundance, protective cover, and snow conditions influenced habitat selection within the home range. In both landscapes, deer were less likely to use open habitat categories as snow accumulated on the ground. At a finer scale, deer inhabiting the regenerated landscape intensively used areas where balsam fir cover was intermediate with greater balsam fir browse density than in the rest of the home range. In the recently logged landscape, deer were more likely to be found near edges between clear-cuts and balsam fir stands and in areas where windblown balsam fir trees were present; the latter being the most influential variable. Although balsam fir browse was sparse and mainly out of reach in this landscape, deer increased the use of areas where it was present. Our results offer novel insights into the resource selection processes of northern ungulates, as we showed that access to winter forage, such as woody browse and alternative food sources, depends on climatic conditions and stochastic events, such as abundant compacted snow or windthrows. To compensate for these scarce and unpredictable food supplies, deer selected habitat categories, but mostly areas within those habitat categories, where the likelihood of finding browse, litterfall, and windblown trees was greatest. © 2011 The Wildlife Society.     

Overabundant wild ungulate populations in Europe: management with consideration of socio-ecological consequences

1. Throughout recent years, ungulates have experienced significant increases in numbers and geographic range sizes in Europe, becoming locally overabundant populations in some regions. Changes in legislation regarding poaching, abandonment of land and re-naturalisation of habitats, and decreasing numbers of hunters, among other things, have led to alarming scenarios in wild ungulate biology. Although ungulates bring some financial benefits for ecosystems and society through tourism and hunting, the problems associated with populations that are no longer controlled can outweigh the advantages. Damage to forestry and agriculture, ungulate-vehicle collisions, and diseases are among the most concerning problems related to ungulate overabundance.
2. To deal with these problems and to decide on the best management strategy to apply, it is essential to have tools available to monitor populations with an integrative approach based on ecological change indicators, and to assess population and ecosystem status. Furthermore, in a globalised world, people’s opinions matter, and sociological studies regarding human perception of wild mammals must take place in order to allow proper management, including consideration of people’s expectations as well as animal and ecosystem needs. Successful and unsuccessful management strategies have already been attempted, and the knowledge of consequences over time enables an adaptive approach.
3. Management of ungulate populations is a complex subject, and each case should be studied, analysing the cost_performance balance of measures to be taken, and ensuring ongoing financial means to carry out and continue with successful ecosystem management strategies. Multidisciplinary teams should be built, including biologists, veterinarians, stakeholders, sociologists, and others, to deal with the management of European wild ungulate populations.

     

Deer and elk hunter recruitment,retention, and participation trends in Montana

Big game hunting is the most popular type of hunting in the United States, and deer and elk hunting are the most popular type of hunting in Montana. Similar to other states, deer and elk hunting also generates most of the revenue spent on wildlife conservation by the state of Montana. Although nationwide trends indicate a concerning decline in hunter participation, the trends in license sales and hunter participation within most states have not received as much attention. We investigated trends in resident deer and elk license sales in Montana using existing licensing databases. We then estimated hunter recruitment, hunter participation, and license purchasing probabilities using hunter education and licensing databases. We employed a multi-state mark–recapture model and 248,819 records of deer and elk license purchasing habits for individual Montana residents during 2002–2007. We used matrix population models to examine the relative influence of these parameters on trends in license sales and hunter participation. Resident deer and elk license sales increased 4% in Montana during 2002–2007. We found that males had greater recruitment rates, retention rates, and license purchasing probabilities than females, and that young adults had lesser license purchasing probabilities than other age classes. Based on analyses of matrix population models, trends in license sales in Montana are most influenced by middle-aged and baby boomer male license purchase probabilities. Trends in hunter participation are positively influenced by recruitment and retention in all male age classes, with the smallest predicted effects arising from recruitment of young adult males. Our results suggest that a focus on older age class males with programs designed to increase hunter recruitment, retention, and license purchase probabilities may have similar or larger effects on trends in license sales and hunter participation in Montana than programs directed at youth. Our analyses also provide a framework by which trends in hunter recruitment, retention, and license purchasing habits can be objectively quantified in order to inform and evaluate hunter recruitment, retention, and license purchase habit programs. © 2011 The Wildlife Society.     

Policy learning and deer co-management in New York State: Insights from newspaper coverage

Resolution of urban and suburban deer problems often depends on learning and co-management. Local newspapers may reflect the learning occurring in a community. Past authors have identified 4 primary types of learning (technical, conceptual, social, and political). We studied newspaper content related to deer management for insights about the types of learning occurring in selected regions in New York State. We analyzed 263 newspaper articles published between 2000 and 2006. We found that the majority of content related to learning focused on conceptual and technical learning, but relatively little, particularly early in the evolution of deer management issues, focused on social or political learning. Our results suggest that additional attention to social learning focusing on collaborative relationships and constructive dialogue among stakeholders by both communities and newspapers could be beneficial in the resolution of deer problems. © 2012 The Wildlife Society.     

Regional-Scale Assessment of Deer Impacts on Vegetation Within Western Connecticut,USA

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.