Graham C Smith - Academia.edu (original) (raw)

Papers by Graham C Smith

The Journal of Applied Ecology, 1991

Journal of Applied Ecology (1991), 28, 454-466 A FIELD TRIAL EVALUATING BAIT UPTAKE BY AN URBAN F... more Journal of Applied Ecology (1991), 28, 454-466 A FIELD TRIAL EVALUATING BAIT UPTAKE BY AN URBAN FOX (VULPES VULPES) POPULATION By WJ TREWHELLA, STEPHEN HARRIS, GC SMITH AND AK NADIAN* Department of Zoology, University of Bristol, Woodland ...

Maps displaying model outputs based on: (a) a 10 km raster grid considering all records;... more Maps displaying model outputs based on: (a) a 10 km raster grid considering all records; (b) a 1km raster using only records with resolution of 1km or higher (aggregated to 10km for comparison); combined across all species to give: (i) predicted species richness; (ii) Minimum predicted biomass; (iii) Maximum predicted biomass. There is good agreement between predicted richness and that observed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0176339#pone.0176339.g001" target="_blank">Fig 1</a>. However, there is a degree of inconsistency, particularly based on a 10km raster, between the spatial distributions of minimum and maximum biomass.</p

Outline of modelling process for each species (maps show output for the hedgehog: <i&... more Outline of modelling process for each species (maps show output for the hedgehog: Erinaceus europaeus; for detailed discussion of these results refer to the species specific report in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0176339#pone.0176339.s006" target="_blank">S6 File</a>). Initially, occurrence is coupled with environmental data comparing 7 SDMs to identify the “best” habitat suitability map based on AUC. This is repeated 100 times with the best maps combined to produce an overall mean habitat suitability; the mid value indicates the threshold above which occurrence is assumed. For these cells, habitat suitability scores are then matched with extracted density estimates and linear regression performed to predict abundance.</p

PLOS ONE, 2021

Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tubercu... more Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tuberculosis in cattle for a number of years. Badger vaccination is also possible, and a move away from culling was “highly desirable” in a recent report to the UK government. Here we used an established simulation model to examine badger control option in a post-cull environment in England. These options included no control, various intermittent culling, badger vaccination and use of a vaccine combined with fertility control. The initial simulated cull led to a dramatic reduction in the number of infected badgers present, which increased slowly if there was no further badger management. All three approaches led to a further reduction in the number of infected badgers, with little to choose between the strategies. We do note that of the management strategies only vaccination on its own leads to a recovery of the badger population, but also an increase in the number of badgers that need to be va...

Human–Wildlife Interactions, 2009

Invasive alien species (IAS) threaten global biodiversity; they are the major cause of species ex... more 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....

One Health Outlook, 2021

The novel coronavirus SARS-CoV-2 likely emerged from a wildlife source with transmission to human... more The novel coronavirus SARS-CoV-2 likely emerged from a wildlife source with transmission to humans followed by rapid geographic spread throughout the globe and severe impacts on both human health and the global economy. Since the onset of the pandemic, there have been many instances of human-to-animal transmission involving companion, farmed and zoo animals, and limited evidence for spread into free-living wildlife. The establishment of reservoirs of infection in wild animals would create significant challenges to infection control in humans and could pose a threat to the welfare and conservation status of wildlife. We discuss the potential for exposure, onward transmission and persistence of SARS-CoV-2 in an initial selection of wild mammals (bats, canids, felids, mustelids, great apes, rodents and cervids). Dynamic risk assessment and targeted surveillance are important tools for the early detection of infection in wildlife, and here we describe a framework for collating and synth...

Veterinary Parasitology, 2017

The parasitic tapeworm Echinococcus multilocularis is the causative agent of alveolar echinococco... more The parasitic tapeworm Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a serious zoonotic infection present in Europe that can be fatal. The United Kingdom currently has E. multilocularis free status but the possibility of introduction exists, most likely via an imported or returning dog or other deliberately introduced animal that has not had anthelmintic treatment. We have developed a model to predict the probability of successfully eliminating a focal outbreak of E. multilocularis using a programme of anthelmintic bait distribution. We investigated three different potential control programmes, each with 36 monthly campaigns commencing five, ten or 15 years after disease introduction over an area of 2827 km 2. We assumed equilibrium disease prevalence of 30%, 40% and 55% based on the range of values reported across Europe. However, for all of these scenarios, equilibrium had not been reached at five to 15 years after introduction and simulated local prevalence values were between 0.5% and 28%. We found that it is possible to eliminate the disease with a 38%-86% success rate if control is started five years after introduction, dropping to 0% to 56% if control is delayed until 15 years after introduction, depending upon the prevalence equilibrium. We have also estimated the costs involved in these programmes to be from D 7 to D 12 million (2013 prices).

PloS one, 2016

Bovine tuberculosis (bTB) causes substantial economic losses to cattle farmers and taxpayers in t... more Bovine tuberculosis (bTB) causes substantial economic losses to cattle farmers and taxpayers in the British Isles. Disease management in cattle is complicated by the role of the European badger (Meles meles) as a host of the infection. Proactive, non-selective culling of badgers can reduce the incidence of disease in cattle but may also have negative effects in the area surrounding culls that have been associated with social perturbation of badger populations. The selective removal of infected badgers would, in principle, reduce the number culled, but the effects of selective culling on social perturbation and disease outcomes are unclear. We used an established model to simulate non-selective badger culling, non-selective badger vaccination and a selective trap and vaccinate or remove (TVR) approach to badger management in two distinct areas: South West England and Northern Ireland. TVR was simulated with and without social perturbation in effect. The lower badger density in Northe...

Management of disease in wild mammals., 2009

Epidemiology and Infection, 2013

SUMMARYStatistical models of epidemiology in wildlife populations usually consider diseased indiv... more SUMMARYStatistical models of epidemiology in wildlife populations usually consider diseased individuals as a single class, despite knowledge that infections progress through states of severity. Bovine tuberculosis (bTB) is a serious zoonotic disease threatening the UK livestock industry, but we have limited understanding of key epidemiological processes in its wildlife reservoirs. We estimated differential survival, force of infection and progression in disease states in a population of Eurasian badgers (Meles meles), naturally infected with bTB. Our state-dependent models overturn prevailing categorizations of badger disease states, and find novel evidence for early onset of disease-induced mortality in male but not female badgers. Males also have higher risk of infection and more rapid disease progression which, coupled with state-dependent increases in mortality, could promote sex biases in the risk of transmission to cattle. Our results reveal hidden complexities in wildlife dis...

Epidemiology and Infection, 2013

Ecological Modelling, 1997

Spatial processes are particularly suitable to being modelled by cellular automata. Ruxton (1996)... more Spatial processes are particularly suitable to being modelled by cellular automata. Ruxton (1996) showed the importance of the ordering of events in simple automata. Each cell within the array could be occupied by one entity (individual or population) or empty, and was subject to two events, a probability of extinction and a probability of colonising a neighbouring empty cell. Four orderings of these events were considered: (a) extinction was considered in numerical order within the array, and then colonisation was considered in the same order; (b) extinction was considered randomly without replacement, and then colonisation was considered randomly; (c) all events were considered in a random order without replacement, thus extinction and colonisation were considered to occur interdependently; (d) a similar number of events were considered randomly with replacement, so the location and type of event was random thus permitting each cell to be considered for more or less than one event of each type. The choice of ordering method used in the simulation had dramatic effects on the outcome, with more

This study sought to determine whether a change in the abundance of feral cats (Felis catus) in t... more This study sought to determine whether a change in the abundance of feral cats (Felis catus) in three areas of England had occurred between the completion of a survey undertaken by the Ministry for Agriculture Fisheries and Food in 1986/7 and the turn of the century. In the event of a rabies outbreak occurring in Britain, feral cats would be one vector of the disease that would need to be controlled under the Rabies (control) Order 1974. A total of 741 “high risk sites”, found to provide appropriate conditions for feral cats, were surveyed between 1999 and 2000. The total number of feral cat colonies located within the survey areas was found to have fallen by 37% from 68 in 1986 to 43 in 1999/2000, translating to an estimated 212-247 fewer individual feral cats. Factories/trading estates and industrial premises continued to be the most common sites associated with urban feral cat colonies. However, the closing down of many traditional industries, such as mills and dockyards, and the...

ABSTRACTOver a 15 month period the removal rates of different attractant and flavour enhanced bai... more ABSTRACTOver a 15 month period the removal rates of different attractant and flavour enhanced baits, by foxes, was investigated at permanent and single use sites. All baits were composed of mechanically recovered chicken meat (MRM) and were treated with one of four additives (an attractant or flavour); untreated baits were used as experimental controls. The addition of synthetic ferment egg (SFE) increased bait removal compared with untreated and valeric acid (VA) treated bait. However, the addition of beef flavour or honey flavour to bait did not increase bait removal rates compared to untreated bait.There was limited evidence of learning (by foxes and other species responsible for removing the bait) at one of the permanent study sites but no evidence of such behaviour at the other site. There was no evidence of consistent seasonal differences in bait removal rates.It was concluded that the use of attractants may increase bait removal rate in areas where bait removal rate is low; b...

Ecological Modelling, 2017

Population size estimates are an integral part of any species conservation or management project.... more Population size estimates are an integral part of any species conservation or management project. They are often used to evaluate the impact of management intervention and can be critical for making decisions for future management. Distance sampling and camera trapping of unmarked populations are commonly used for such a task as they can yield rapid and relatively inexpensive estimates of density. Yet, while accuracy is key for decision-making, the potential bias associated with densities estimated with each method have seldom been investigated and compared. We built a spatially-explicit individual based model to investigate the accuracy and precision of both monitoring techniques in estimating known densities. We used the wild boar population of the Forest of Dean, UK, as a case study because both methods have been employed in situ and offer the chance of using real life parameters in the model. Moreover, this is an introduced species in the UK that has the potential to impact natural and agricultural ecosystems. Therefore, improving the accuracy of density estimates is a priority for the species' management. We found that both distance sampling and camera trapping produce biased density estimates for unmarked populations. Despite large uncertainties, distance sampling estimates were on average closer to known densities than those from camera trapping, and robust to group size. Camera trapping estimates were highly sensitive to group size but could be improved with better survey design. This is the first time that the amount of bias associated with each method is quantified. Our model could be used to correct estimated field-based densities from distance sampling and camera trapping of wild boar and other species with similar life-history traits. Our work serves to increase confidence in the results produced by these two commonly-used methods, ensuring they can in turn be relied upon by wildlife managers and conservationists.

PloS one, 2017

Robust policy decisions regarding the protection and management of terrestrial mammals require kn... more Robust policy decisions regarding the protection and management of terrestrial mammals require knowledge of where species are and in what numbers. The last comprehensive review, presenting absolute estimates at a national scale, was published nearly 20 years ago and was largely based on expert opinion. We investigated and propose a systematic data driven approach combing publically available occurrence data with published density estimates to predict species distribution maps and derive total abundance figures for all terrestrial mammals inhabiting Britain. Our findings suggest that the methodology has potential; generally producing plausible predictions consistent with existing information. However, inconsistencies in the availability and recording of data impact the certainty of this output limiting its current application for policy. Restrictions on access and use of occurrence data at a local level produces "data deserts" for which models cannot compensate. This leads ...

PloS one, 2017

Policy development, implementation, and effective contingency response rely on a strong evidence ... more Policy development, implementation, and effective contingency response rely on a strong evidence base to ensure success and cost-effectiveness. Where this includes preventing the establishment or spread of zoonotic or veterinary diseases infecting companion cats and dogs, descriptions of the structure and density of the populations of these pets are useful. Similarly, such descriptions may help in supporting diverse fields of study such as; evidence-based veterinary practice, veterinary epidemiology, public health and ecology. As well as maps of where pets are, estimates of how many may rarely, or never, be seen by veterinarians and might not be appropriately managed in the event of a disease outbreak are also important. Unfortunately both sources of evidence are absent from the scientific and regulatory literatures. We make this first estimate of the structure and density of pet populations by using the most recent national population estimates of cats and dogs across Great Britain...

Tuberculosis, 2001

Following the first model of wildlife tuberculosis (in European badgers) there has been a spate o... more Following the first model of wildlife tuberculosis (in European badgers) there has been a spate of papers modelling wildlife TB. These have looked at population parameters and disease dynamics in the badger and possum. Recent papers in particular have looked at various methods of controlling the wildlife vector to reduce the incidence of TB in cattle. The author examines the role of modelling to show what insights it has given us, which issues have not been addressed, and where the shortfalls lie. Particular attention will be paid to a comparison between models of badgers and possums, and between simple and more complex models, and possible areas of future research will be revealed.

The Journal of Applied Ecology, 1991

PLOS ONE, 2021

Human–Wildlife Interactions, 2009

One Health Outlook, 2021

Veterinary Parasitology, 2017

PloS one, 2016

Management of disease in wild mammals., 2009

Epidemiology and Infection, 2013

Ecological Modelling, 1997

Ecological Modelling, 2017

PloS one, 2017

Tuberculosis, 2001