Monday, 30 November 2015

Berkshire Mammal Group Talk - Riversearch

Jim Jones, Surrey Wildlife Trust. 5th November 2015


 





Speaking to the Berkshire Mammal Group at its new venue in Park Church, Reading, Jim introduced himself as a former dispatch rider and care worker, before he read for a BSc at Plymouth and an MSc at UEA. His first post was with the People’s Trust for Endangered Species and he now works for Surrey Wildlife Trust as Wetland Landscapes Officer. He is also Vice Chairman of Surrey Mammal Group and a trainer for the Mammal Society.

Outline of the talk


Helping riparian mammals recover, especially otters and water voles, and using people in partnership to understand where these animals actually are, is how Jim set out his theme – and to encourage a landscape approach to nature conservation. 
 

1. Otter and Water Voles

Otters have been in tremendous decline since the 1950s – caused by DDT pesticides and, to a lesser extent, hunting – surviving only in the South West and Wales. Interestingly, a 1905 book on hunting reports an otter hunt in Chiddingfold where Jim now lives. Now, however, the otter is present in every county in England, though still scarce in the South East; the North Downs act as a watershed and otters are few south of them, in Hampshire, Sussex and Kent. 

Water voles
Hedgehogs excepted, the water vole is Britain’s most rapidly declining mammal, a fate propelled by intensive agriculture (ploughing up to the bank, for instance), development of the flood plains, even a lack of management that allows the growth of scrub and trees to prevent the lush vegetations that voles need. On top of this, the American mink is a modern menace. Smaller in size than the otter, the mink has a white chinstrap rather than bib, and creates a bow wave when swimming. Interestingly, when their territories overlap with those of polecats, the sex bias of the latter is affected, with a diminishing number of females.



Jim Jones

The status of river mammals in Surrey
The current distribution map includes records dating back 15 years and so must be regarded as an unreliable reflection of population. Otters are recorded on the Mole and Eden to the east of the county, with more coming into the catchment of the River Wey from Hampshire. The pattern is more marked in the case of voles; ten years ago they were on the Mole, but now are just on the Wey, while mink are found throughout the county, even the central Surrey Hills.

Record keeping
Local records are sent to the National Water Vole Database & Mapping Project, 2009-14, from which ‘alert maps’ are produced and both local and regional key areas proposed for conservation.
 

2. Water vole recovery plan

A six-point plan to reverse the trend was introduced when Jim became Wetlands Officer:
  1. Going back to the existing sites for a status update
  2. Reintroduction of animals if needed
  3. Inform local authority planning departments
  4. Habitat management where existing sites are suitable
  5. Creation of new habitats in key areas if needed
  6. Mink control – a collective action with landowners, at catchment level.

3. RiverSearch

Building on previous attempts at surveying ‘wet’ mammals, and the work of river wardens, RiverSearch was launched in 2012. Taking its inspiration from the work of Darren Tansley of the Essex Wildlife Trust from 2007, it collects data on the otter, water vole, water shrew and harvest mouse. Starting from scratch, Surrey’s new volunteers are trained at Darren’s house. Volunteers are asked to adopt a one km stretch of river and monitor it at least once a season. The resulting data are captured by a river co-ordinator for prioritisation and planning.

117 volunteers recruited
82 volunteers trained
71 stretches of the Wey and Mole covered
23 mammal surveyors trained

Vole Patrol 2015 is a 60-site survey on the Wey, Mole and Blackwater. There was also a vole-raft project conducted by Nick Mason of Nottingham Trent University, designed to indicate the presence of voles by the traces of excrement left behind. Negative results were obtained at 20 to 30 sites, before Nick moved on and found success in Hampshire.

Vole Reintroduction
Several suitable sites have been identified, including Stoke Meadows, next to the A3 at Guildford, and Nutfield Marshes at Redhill. If no voles are located, then reintroduction on these sites will be attempted. However, £150,000 would be needed to prepare the sites. 
 
Otter surveys
The 5th Otter Survey of the UK identified two positive sites were in Surrey, and Jim’s Otter Bridge Blitz of 2014 found spraint under selected bridges around Guildford. 
 
Photography project
A University of Surrey / SWT project was established in 2013 to monitor the riverbanks with cameras. Aaron, a student at the university, installed live-action camera traps and succeeded in obtaining lots of otter pictures that year, supplemented by images from John Hawkins Wildlife Photography. Analysis of the frequency of visits to the traps indicated a pattern a couple of days’ activity followed by absences of either one or two weeks before returning. This was in July and August when such a level of activity is atypical of otters. Eventually one animal was found, injured or unwell, and while at the sanctuary, it was discovered to have been ‘chip-and-pinned’ by a Somerset Hospital that had released one originally from Devon and two originally from North Wales. (Out-of-area releases – possibly due to overcrowding – can be problematic and spread diseases such as liver fluke.) However, no sightings of otters have since been reported in Surrey and presumably they have moved on.

4. Landscape

Jim seeks bigger, joined-up landscapes and asks how mammal projects can indicate or even initiate progress toward this aim. He points to ‘catchment partnerships’ and notes that RiverSearch also monitors pollution, barriers and the presents of non-natives, besides helping in practical work of enhancing channels and maintaining the banks. He gave examples of multiple-benefit projects: Wey Meadows and Wet Heath & Mire Project (Devil’s Punchbowl)

5. Surrey Harvest Mouse
Increasingly found in wetlands, harvest mice are a monitor of how joined-up the landscape might be. For the Surrey project the team experimented to establish which traps would be best: Longworth (“best”), plastic (“OK”) and Sherman (“hated”) – at stalk height or on the ground. Apparently the position made little difference, but many more were found in the morning than after midday. 26 mice were found in one field alone.

Second Phase: Genetics
Genetic testing, by fur plucking, is seeking to establish connectivity or insularity of population. Testing is conducted by the university at Brighton. For success 15-20 animals are required per site, and so volunteers are being trained to search for nests. The first four yielded nothing, but the fifth site, 18; the last, 32; the current, 10 and counting. This is exciting stuff – the first project in the UK to look at population genetics; the only other is in Taiwan, with which Jim keeps in correspondence. Harvest mice inhabit the entire Eurasian land mass.

Questions and Discussion

- Will otters benefit if mink numbers are reduced? Probably not, as they co-exist relatively independently.

- How does the European mink interact with voles. Not sure, but less aggressive than its American counterpart.

- If banks need management, then perhaps riparian mammals are being artificially encouraged by conservationists? Why bother? Because the rest of the landscape is also artificial and man has assumed the responsibility of attaining balance.

- Is harvest mouse trapping only conducted in the autumn? This is the peak time in terms of population. 90% die over winter and the population has to recover in the spring.

- Harvest mice are increasingly found in wetland sedges. Perhaps they always were there, if not as noticeably as in arable grasses. They have declined in fields, but still continue especially around the edges and near the hedgerows.

- RiverSearch is sponsored by the brewer, SAB Miller.

- No sign of otters in 2014 after losing sight of the 2013 family. They travel throughout a 40-50km range, at very low density. There are only ten along the River Itchen in Hampshire!

Edwin A.R. Trout,
Berkshire Mammal Group

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