Papers by Jonathan Reynolds
Biological Conservation, Apr 30, 2001
We developed and tested physical excluders to prevent non-target animals from entering tunnels co... more We developed and tested physical excluders to prevent non-target animals from entering tunnels containing spring traps intended to kill a range of small (<2 kg) mammalian pest species. In ®eld trials over 82,954 trap-nights, excluders did not signi®cantly decrease stoat (Mustela erminea) or weasel (Mustela nivalis) capture rates, but did substantially reduce the capture rate of larger target species, notably grey squirrels (Sciurus carolinensis) and rats (Rattus norvegicus). Excluders virtually eliminated capture of hedgehogs (Erinaceus europaeus) -a legally protected species. By inference, larger protected species (polecat Mustela putorius, pine marten Martes Martes, otter Lutra lutra and wild cat Felis sylvestris) would be excluded, as would mink (Mustela vison), a legitimate target species. These excluders should be advocated where there is a real risk of catching protected species. However, because excluders compromise utility, we recommend that their use should remain discretional unless clearly preferable alternative methods to manage target pest species are developed. #
Wildlife Research, 2011
Abstract Context: Sampling methods to estimate animal density require good survey design to ensur... more Abstract Context: Sampling methods to estimate animal density require good survey design to ensure assumptions are met and sampling is representative of the survey area. Management decisions are often made based on these estimates. However, without knowledge of true population size it is not possible for wildlife biologists to evaluate how biased the estimates can be if survey design is compromised. Aims: Our aims were to use distance sampling to estimate population size for domestic sheep free-ranging within ...
Journal of Wildlife Management, 2010
American mink (Neovison vison) are an ecologically damaging invasive species where they have been... more American mink (Neovison vison) are an ecologically damaging invasive species where they have been introduced in Europe.
Biological Conservation, 2001
We developed and tested physical excluders to prevent non-target animals from entering tunnels co... more We developed and tested physical excluders to prevent non-target animals from entering tunnels containing spring traps intended to kill a range of small (<2 kg) mammalian pest species. In ®eld trials over 82,954 trap-nights, excluders did not signi®cantly decrease stoat (Mustela erminea) or weasel (Mustela nivalis) capture rates, but did substantially reduce the capture rate of larger target species, notably grey squirrels (Sciurus carolinensis) and rats (Rattus norvegicus). Excluders virtually eliminated capture of hedgehogs (Erinaceus europaeus) -a legally protected species. By inference, larger protected species (polecat Mustela putorius, pine marten Martes Martes, otter Lutra lutra and wild cat Felis sylvestris) would be excluded, as would mink (Mustela vison), a legitimate target species. These excluders should be advocated where there is a real risk of catching protected species. However, because excluders compromise utility, we recommend that their use should remain discretional unless clearly preferable alternative methods to manage target pest species are developed. #
The Journal of Wildlife Management, 2013
The introduction of American mink (Neovison vison; hereafter mink) into Europe has had severe imp... more The introduction of American mink (Neovison vison; hereafter mink) into Europe has had severe impacts on many native wildlife species, including the water vole (Arvicola amphibius) in mainland Britain. Although trapping has been widely used to attempt to control mink, managers have little direct evidence of its effect on mink density or distribution, particularly where immigration of mink from nearby areas is inevitable. Such evidence is needed to justify the use of lethal methods in conservation policy. During 2006-2010 we removed mink from the River Monnow Catchment in western Britain, using track-recording rafts to monitor continuously for mink presence, guiding a strategic trapping effort. The area monitored and trapped was increased in stages, from a core sub-catchment with 109 km of water-course in 2006, to a 421km 2 catchment with 203 km of water-course in 2009. In each successive sub-catchment, mink detection and capture rates declined rapidly to near-zero levels after trapping began. Detections and captures showed seasonal peaks in every year corresponding to known dispersal periods, but also declined steadily from year to year, with increasing periods in which we did not detect mink. These results suggested that each subcatchment was cleared of mink within a few months, with subsequent captures attributable to immigration. On average, we detected each mink 5.1 times before capture (daily probability of detection ¼ 0.059 per mink and raft), and trapped them 3.4 days after deploying traps in response. On average, mink entering the area were likely to have been present for less than 13 days before capture. Water voles had been extinct in the Monnow Catchment since the 1980s. During 2006-2008 (starting 6 months after mink trapping commenced), we released 700 captive-bred water voles into the treatment area to re-establish a wild population. Persistence of this population through the 4 years of the project was considered indicative of effective mink control. This study demonstrates that, even in a mainland context, a systematic trapping strategy can have a substantial impact on the density and distribution of a damaging species, in this case allowing the restoration of a native prey species. ß 2013 The Wildlife Society
European Journal of Wildlife Research, 2012
Abstract American mink (Neovison vison) are an ecologically damaging invasive species in Europe a... more Abstract American mink (Neovison vison) are an ecologically damaging invasive species in Europe and Iceland where attempts to control them typically rely on trapping. The focus and efficiency of trapping can be improved by using track-recording mink rafts to identify where mink are present before traps are deployed. This paper describes development of operating strategy for the use of mink rafts with traps, to optimise capture efficiency against costs. We worked sequentially on two unconnected chalk streams in central southern England. On ...
SUMMARY 1. In the UK the population of Mute swans (Cygnus olor) has doubled since the early 1980s... more SUMMARY 1. In the UK the population of Mute swans (Cygnus olor) has doubled since the early 1980s. Swans feed mainly on submerged aquatic macrophytes, especially water crowfoots (Ranunculus spp. subgenus Batrachium). The River Avon (a chalk-stream in southern England) is designated a Special Area of Conservation, in which Ranunculus-dominated habitat is required to be protected. This study focused on the River Wylye (part of the Avon catchment) to quantify the impact of grazing by swans on the biomass of ...
European Journal of Wildlife Research, 2010
The brown hare Lepus europaeus is a valued game species but also a species of conservation concer... more The brown hare Lepus europaeus is a valued game species but also a species of conservation concern owing to its severe decline in abundance on farmland throughout Europe during the twentieth century. Changes in the farmland habitat and predation have both been cited as causative factors. Their relative roles have been unclear, but most conservation action has focused on improving habitat. We analyse data from a sequence of three unique studies (one experiment and two demonstrations) covering the period 1985–2006 in which control of several common predator species was undertaken to increase densities of wild game on farmland in England. Across the three studies, regression modelling of the proportional change in hare numbers between successive years showed that—after site, year differences and harvesting were accounted for—predator control was a significant determinant of hare population change. Where habitat improvement also took place, hares reached autumn densities that were exceptional for the UK and which could sustain substantial harvests. When predation control was stopped, hare densities fell, even where habitat improvements remained in place. This analysis demonstrates that even where farmland habitat is greatly improved, uncontrolled predation prevents hares making full use of its carrying capacity. This helps explain the mixed—and at best modest—success of agri-environment schemes in the UK and elsewhere in Europe to increase hare densities. Game-shooting estates, on which effective predator control takes place, probably have a special significance within the landscape as source areas for brown hares.
Mammal Review, 2003
1. Foxes Vulpes vulpes probably did not occur naturally on the Isle of Man, but were present in s... more 1. Foxes Vulpes vulpes probably did not occur naturally on the Isle of Man, but were present in small numbers in the mid 19th century. They were introduced again in the 1980s, and in 1990 the population was estimated at 120-300 individuals (20-50 per 100 km 2 ) on the basis of field signs. We used a nocturnal spotlight transect survey technique to assess the status of foxes on the Isle of Man in September 1999. This method had previously been used effectively to estimate fox densities in populations as sparse as 16 per 100 km 2 . We surveyed a total of 852 km over a period of eight consecutive nights, during weather conditions which allowed excellent visibility. No foxes were seen. 2. By comparison with equivalent survey efforts in reference areas of mainland Britain, we conclude that post-breeding fox density on the Isle of Man was certainly below 2.5 per 100 km 2 , implying a maximum of 15 foxes on the entire island. We estimate a probability of only 15-25% that a fox population of 1 per 100 km 2 was present but not detected; this would be equivalent to only five or six individuals on the whole island. Foxes may even be entirely absent, although unsubstantiated sightings continue to be reported. 3. This finding is significant in understanding the ecology of the Isle of Man, and in planning the conservation of a number of ground-nesting bird species there, as well as for farming interests, and for contingency planning against an accidental introduction of rabies.
Nature, 2003
Abstract The potential impact of fox-hunting ban in Britain is a contentious issue 1 that has bee... more Abstract The potential impact of fox-hunting ban in Britain is a contentious issue 1 that has been explored by Baker et al. 2. They conclude that a suspension of lowland fox-hunting for nine months during 2001 made no difference to fox density in certain areas. We are not confident, however, that their analysis supports their conclusions—their study does not consider statistical power or account sufficiently for regional variation, and also uses an inappropriate statistic.
Mammal Review, 1985
Similarities in general size, geometry, lifestyle, and environment mean that certain energetic co... more Similarities in general size, geometry, lifestyle, and environment mean that certain energetic constraints are common and peculiar to Holarctic tree squirrels as a group. Holarctic tree squirrels are relatively small, diurnal mammals which, in association with their food niche, maintain activity throughout the autumn-winter period. Despite this, they exhibit no major morphological or physiological adaptations to minimize energy expenditure at low temperatures; on the contrary, both basal metabolism and conductance are higher than expected on the grounds of physical size. When they are active energy expenditure is therefore strongly influenced by effective ambient temperature for these species when active in their natural autumn-winter environments. Nest use allows near-basal metabolism at most natural ambient temperatures. The balance of economical inactivity against feeding rewards offset by cold exposure must therefore be a crucial aspect of the lifestyle of these squirrels.
Mammal Review, 1991
Failure to address many of the difficulties inherent in the analysis of carnivore faeces has hith... more Failure to address many of the difficulties inherent in the analysis of carnivore faeces has hitherto limited the value of this technique in comparing carnivore diets or quantifying carnivore food consumption. In this review, major problems are discussed, and improved procedures designed to overcome them are recommended.The principal improvements recommended for laboratory procedures address the microscopic fraction of faeces, which cannot be analysed visually. This fraction may be derived from a variety of sources, leading to bias in previous techniques, particularly with regard to the importance of earthworms and birds. Attention to the microscopic fraction is necessary for correct comparison or quantitative determination of diet.Particular attention is given to statistical procedures which quantify the errors that arise in collection of samples, or during analysis. Clear statement of such errors will lead to greater comparability between studies. The procedures recommended here define the limits to accuracy in relation to sample size, total faecal production, and laboratory methods. In conjunction with adequate pilot studies, these techniques will allow more effective design of ecological studies relating to carnivore diet and food consumption.
Journal of Zoology, 2000
Page 1. Demography of rural foxes (Vulpes vulpes) in relation to cull intensity in three contrast... more Page 1. Demography of rural foxes (Vulpes vulpes) in relation to cull intensity in three contrasting regions of Britain Matthew J. Heydon and Jonathan C. Reynolds* The Game Conservancy Trust, Fordingbridge, Hampshire SP6 1EF, UK (Accepted 1 August 1999) ...
Journal of Zoology, 2000
Page 1. Fox (Vulpes vulpes) management in three contrasting regions of Britain, in relation to ag... more Page 1. Fox (Vulpes vulpes) management in three contrasting regions of Britain, in relation to agricultural and sporting interests Matthew J. Heydon and Jonathan C. Reynolds* The Game Conservancy Trust, Fordingbridge, Hampshire SP6 1EF, UK (Accepted 1 August 1999) ...
Journal of Zoology, 2000
Abstract Spotlight transect surveys with distance sampling were used to estimate spring (pre-bree... more Abstract Spotlight transect surveys with distance sampling were used to estimate spring (pre-breeding) and autumn (post-production) fox Vulpes vulpes densities in three contrasting rural areas of Britain during 1995–97. This was the first attempt in Britain to measure and compare fox densities over large geographical areas (630–1460 km 2). Mean post-production fox abundance was estimated to be 0.90/km 2, 2.62/km 2, and 0.59/km 2 in mid-Wales, the east Midlands and East Anglia, falling to pre-breeding levels of 0.41/km 2, 1.17/ ...
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Papers by Jonathan Reynolds