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BDS is contributing both funding and expertise to a joint project being carried out by RSPB and Bournemouth University investigating the populations of sika deer using the RSPB Reserve at Arne in the Isle of Purbeck and the impact they may be having on protected wetlands. The RSPB has for some time been concerned that sika numbers in the Reserve have been increasing over recent years and are now at levels where they are causing serious damage to heathlands, reedbeds and estuarine saltmarsh vegetation. Before making a formal decision about what management is likely to be necessary and what approaches to the problem are likely to be most effective, RSPB is seeking further information on the scale of the problem, and the likely consequences/effectiveness of the different management options available to them. Funding has been provided by RSPB, English Nature, Defence Deer Management and the Wessex Branch to support a project being carried out from Bournemouth University; BDS is involved in the management of the research project (the Hon. Scientific Adviser is on the project Steering Committee) and is also involved in the project in providing comparative information from Lulworth and Bovington Ranges.

For RSPB to determine an effective Management Strategy for the future, they need to have a more detailed assessment of the extent of damage being caused - and whether this is localised to particular areas or is widespread across a number of different habitats. They need clearer understanding of how the local sika deer use the different parts of the Reserve - and indeed, whether or not the 'local' sika deer are in fact a resident and relatively self-contained population within the Arne peninsula, or are simply part of a wider, population more or less continuous with all the other subpopulations of sika distributed throughout the Isle of Purbeck. They also need to explore what may be the possible effects of different managment options available and whether this should include some reduction of the number of sika deer present within the area, or attempts to change their distribution across the Reserve by habitat management methods designed to change the relative attractiveness to the deer of different habitat types available.

Studies being undertaken thus include accurate census of deer numbers and distribution through the Reserve on a regular basis; studies of the different preferences by the deer for different habitat types and how those may change over time;analyses of diet and studies of the actual impact of grazing and trampling on reedbeds, saltmarshes, bogs and heathland communities. Some comparative data are also being collected from elsewhere within the Isle of Purbeck. DDM members have assisted at a number of live-capture operations (conducted under licence from English Nature) to equip a number of individual deer with radiocollars, so that movements may be followed within the Reserve, but also, and importantly, so that the extent of exchange of animals between Arne itself and the wider Isle of Purbeck may be more accurately assessed.

Once all these data have been assembled, they will form the basis for a formal assessment of the true nature of the problems caused by sika at Arne, and an objective appraisal of the likely effectiveness of a variety of different management options available, so that RSPB can make a responsible and fully-informed decision about managment needs for the future.