Piran C. L. White

Effects of roads on badger Meles meles populations in south-west England

Abstract Roads have two major impacts on the landscape with respect to badger populations: (1) the imposition of barriers that reduce or prevent dispersal, and (2) the increased mortality caused by road traffic. Road traffic is the largest single cause of recorded death for badgers Meles meles in Britain. We used data collected by the Ministry of Agriculture, Fisheries and Food during the mid-1980s to quantify the effects of roads on badger populations in south-west England. The probability of badger fatalities per km were expressed as ratios of the number of road deaths per unit length of road for different classes of roads. The relationship between badger road deaths and traffic load appeared to be asymptotic. Despite large differences in traffic load and traffic flow on motorways, dual carriageways, class A and class B roads, they all had similar rates of badger fatalities per unit length of road, which were approximately six times greater than that for class C roads. These results suggest that high traffic loads may discourage badgers from attempting to cross major roads, and that these may therefore reduce movements between adjacent groups. Traffic levels on Britains roads have already increased by 26% since these data were collected. As traffic loads increase further in the next century, the mortality and fragmentation effects of roads on badger populations locally are likely to become increasingly significant.

Bovine tuberculosis in southern African wildlife: a multi-species host–pathogen system

This review examines the current situation of bovine tuberculosis (bTB) in southern African savannah systems, and uses theory on multi-species host-pathogen systems to suggest possible options for future research and management. In southern Africa, the buffalo (Syncerus caffer) and the Kafue lechwe [Marsh antelope] (Kobus leche) have been found to be maintenance hosts for this disease, but the importance of other host species is becoming apparent. The role of other host species in the maintenance and spread of the disease varies, depending on the spatial distribution and resource utilization patterns of the species, disease susceptibility, transmission modes and the ecology of both host(s) and vector(s). Future research needs to identify the pathogenicity of bTB in each of the host species, and the mechanisms and rates of inter- and intra-specific transmission among different species, in order to develop multi-host models to understand the development and spread of the disease.

Flexible spatial organization of urban foxes, Vulpes vulpes, before and during an outbreak of sarcoptic mange

The social and spatial organization of urban fox groups prior to and during an outbreak of sarcoptic mange was compared with predictions derived from the resource dispersion hypothesis (RDH). We investigated the availability of three key resources. Neither daytime rest sites nor breeding sites appeared to be limited in availability. The availability of food deliberately supplied by local householders was examined by questionnaire surveys. The daily and weekly amount of food supplied was greatly in excess of the minimum requirements of a pair of foxes, but was consistent between territories. The availability of this food source increased markedly as a result of more people feeding the foxes. In agreement with the RDH, group size prior to the outbreak of mange increased from 2.25 animals (N=4) to 6.57 animals (N=7). Before the outbreak of mange, two territories were divided. Increased scavenge availability on smaller territories may have promoted these changes. Excluding these spatial changes, territories were very stable between years. After the outbreak of mange, group size declined as a direct result of mange-induced mortality. Surviving animals increased their ranges only after neighbouring groups had died out. Ranges did not increase in size in response to a decline in food availability. Nor were the increases in range size associated with the relinquishment of parts of the existing territory. These postmange changes are contrary to the RDH. Three factors may have promoted these changes: the elimination of interstitial space, the forced dispersal of young or future division of the territory. Copyright 2000 The Association for the Study of Animal Behaviour.

Knowledge exchange: a review and research agenda for environmental management

There is increasing emphasis on the need for effective ways of sharing knowledge to enhance environmental management and sustainability. Knowledge exchange (KE) are processes that generate, share and/or use knowledge through various methods appropriate to the context, purpose, and participants involved. KE includes concepts such as sharing, generation, coproduction, comanagement, and brokerage of knowledge. This paper elicits the expert knowledge of academics involved in research and practice of KE from different disciplines and backgrounds to review research themes, identify gaps and questions, and develop a research agenda for furthering understanding about KE. Results include 80 research questions prefaced by a review of research themes. Key conclusions are: (1) there is a diverse range of questions relating to KE that require attention; (2) there is a particular need for research on understanding the process of KE and how KE can be evaluated; and (3) given the strong interdependency of research questions, an integrated approach to understanding KE is required. To improve understanding of KE, action research methodologies and embedding evaluation as a normal part of KE research and practice need to be encouraged. This will foster more adaptive approaches to learning about KE and enhance effectiveness of environmental management.

Predicting Impacts of Climate Change on Fasciola hepatica Risk

Fasciola hepatica (liver fluke) is a physically and economically devastating parasitic trematode whose rise in recent years has been attributed to climate change. Climate has an impact on the free-living stages of the parasite and its intermediate host Lymnaea truncatula, with the interactions between rainfall and temperature having the greatest influence on transmission efficacy. There have been a number of short term climate driven forecasts developed to predict the following seasons infection risk, with the Ollerenshaw index being the most widely used. Through the synthesis of a modified Ollerenshaw index with the UKCP09 fine scale climate projection data we have developed long term seasonal risk forecasts up to 2070 at a 25 km square resolution. Additionally UKCIP gridded datasets at 5 km square resolution from 1970-2006 were used to highlight the climate-driven increase to date. The maps show unprecedented levels of future fasciolosis risk in parts of the UK, with risk of serious epidemics in Wales by 2050. The seasonal risk maps demonstrate the possible change in the timing of disease outbreaks due to increased risk from overwintering larvae. Despite an overall long term increase in all regions of the UK, spatio-temporal variation in risk levels is expected. Infection risk will reduce in some areas and fluctuate greatly in others with a predicted decrease in summer infection for parts of the UK due to restricted water availability. This forecast is the first approximation of the potential impacts of climate change on fasciolosis risk in the UK. It can be used as a basis for indicating where active disease surveillance should be targeted and where the development of improved mitigation or adaptation measures is likely to bring the greatest benefits.

Encounters between red foxes (Vulpes vulpes): implications for territory maintenance, social cohesion and dispersal

Observations on the behaviour and movements of 11 foxes from seven neigh-bouring groups in an urban area of Bristol were combined with post-mortem data on levels of bite wounding throughout the entire Bristol fox population to quantify the importance of encounters in the maintenance of group cohesion and territory, and to address the social subordination hypothesis (Christian 1970) regarding dispersal behaviour. Inter-group encounters were uncommon and almost always aggressive, and occurred significantly more often in the winter months, when resident males trespassed into neighbouring ranges. Each fox had on average 0.77 inter-group encounters each day in winter, compared with 0.05-0.23 in spring, summer and autumn

Selection of line-transect methods for estimating the density of group-living animals: lessons from the primates.

We review the four major contemporary methods for estimating density of group‐living animals from line‐transect sampling: perpendicular modelling of group centers, perpendicular modelling of center of measurable individuals, strip transects and animal–observer distance. The efficacy of each method is evaluated to produce a simple selection guide. We review the literature and use field data from the Udzungwa Mountains, Tanzania. The review is relevant to all group‐living animals; however, examples are drawn from the primates. Perpendicular methods have better mathematical justification than non‐perpendicular methods. For perpendicular methods using detection function models, it is preferable to measure group location using center of measurable individuals, as group centers are hard to estimate. The assumptions of detection function models are often broken in poor visibility habitats or with unhabituated animals. Alternatively strip transects may be used where there are reliable data on group spread and/or visibility. Strip transects are also the most practical, along with the animal–observer method; however, the latter lacks mathematical justification. We conclude that there are arguments for continued use of all four methods. In certain situations the use of raw encounter rates may also be considered. The appropriate method is determined by minimizing bias and considering time, resources and field conditions. Am. J. Primatol. 70:452–462, 2008.

Marine biodiversity–ecosystem functions under uncertain environmental futures

Anthropogenic activity is currently leading to dramatic transformations of ecosystems and losses of biodiversity. The recognition that these ecosystems provide services that are essential for human well-being has led to a major interest in the forms of the biodiversity–ecosystem functioning relationship. However, there is a lack of studies examining the impact of climate change on these relationships and it remains unclear how multiple climatic drivers may affect levels of ecosystem functioning. Here, we examine the roles of two important climate change variables, temperature and concentration of atmospheric carbon dioxide, on the relationship between invertebrate species richness and nutrient release in a model benthic estuarine system. We found a positive relationship between invertebrate species richness and the levels of release of NH4-N into the water column, but no effect of species richness on the release of PO4-P. Higher temperatures and greater concentrations of atmospheric carbon dioxide had a negative impact on nutrient release. Importantly, we found significant interactions between the climate variables, indicating that reliably predicting the effects of future climate change will not be straightforward as multiple drivers are unlikely to have purely additive effects, resulting in increased levels of uncertainty.

Interdisciplinary approaches for the management of existing and emerging human–wildlife conflicts

Human–wildlife conflicts are increasing throughout the world, principally due to a combination of human population growth, increased pressure on land and natural resources and climate change. Many human–wildlife conflicts stem from differences in objectives between various stakeholder groups, especially where the wildlife in question is a resource that can be exploited for economic or cultural benefit, or where the conservation of wildlife is at odds with human population growth or development pressure. Conflicts can be exacerbated by an incomplete understanding of their causes and/or inappropriate intervention measures. Many traditional forms of intervention are also subject to increasing scrutiny and criticism from society. Here, we highlight the potential strategic benefits that can be made by an interdisciplinary approach to human–wildlife conflict situations, by integrating knowledge and understanding across the natural and social sciences. We also stress the potential tactical benefits from combining new approaches to management with more traditional ones. We emphasise the potential contribution of more recent developments in decision-making under conditions of limited data availability and uncertainty. Finally, we recommend that monitoring should play a more prominent role, both in assessing the role of stakeholder engagement in participatory decision-making and in contributing to the evidence base that will allow competing hypotheses about specific systems to be evaluated in an iterative manner.

Fox contact behaviour and rabies spread : a model for the estimation of contact probabilities between urban foxes at different population densities and its implications for rabies control in Britain

1. Contacts between susceptible and infectious individuals determine how fast a disease will spread. However, they are difficult to measure in the wild, and most models of disease spread have been forced to use estimated or derived values. 2. In this paper, a mathematical relationship between fox home range size and population density is derived from the literature and combined with behavioural data on movement patterns and encounters from urban Bristol, UK to formulate a predictive model of inter-group contact probabilities over a range of population densities. 3. This contact probability-population density relationship is used to formulate a revised version of the rabies model of Smith & Harris (1991), which is the model used by the Ministry of Agriculture, Fisheries and Food as the basis of its rabies control policy for an outbreak of the disease in an urban area of Britain. 4. The original and revised versions of the model are compared in terms of their predictions for the rate of rabies spread and their implications for rabies control in specific urban areas. 5. An equivalent probability of successful rabies control is achieved by 5-15% lower fox control for the revised model compared with the original one. The greatest differences between the probability of successful rabies control for a given level of fox control under the two versions of the model occur in winter. 6. The revised model predicts that the rate of rabies spread will be slower than predicted by the original model. This is due to the lower inter-group contact probabilities used in the revised model. Thus, there will be a greater chance of containment and elimination of the disease within a specified control area than was suggested by the original model. 7. The heterogeneous nature of the urban landscape probably results in a lower frequency of contacts than would be observed between foxes living at the same densities in rural environments.