Independent Scientific Group On Cattle TB (ISG): Response to the independent audit of the badger culling trial field operations
1. The audit covered the design and implementation of Standard Operating Procedures (SOPs) designed by the ISG for the surveying of badger field signs and the delineation of badger territories from those field signs. The aim was to evaluate MAFF's initial surveys and subsequent attempts to assign badger setts to social group territories. The Auditors conducted intensive re-surveys of selected areas usually several months after the completion of MAFF's surveys. The audit covered the early part of the trial, mostly in the first two triplets, and involved the use of intensive techniques, such as bait marking, which were not used by MAFF staff.
2. The ISG notes that the audit covers field work carried out during 1998 and 1999 in the first triplets of the trial, when staff were unfamiliar with some of the techniques to be used and when some of the SOPs had not been finalised. We also note that there are no gold standards in the study of disrupted badger populations; the Auditors themselves found their data, collected by using more sophisticated techniques and less time constraints, difficult to interpret and liable to change over time.
3. Although some problems were identified the large majority of main setts were accurately located and mapped. We note that all of the larger setts missed were in scrub or woodland and, therefore, support the Auditors' recommendation that staff more frequently adopt a team approach to surveying difficult habitats, as suggested in the SOP. The Auditors' finding that some setts had been mis-classified causes some concern although this must be tempered by the facts that:
a) the data indicate that some sett classifications did appear to change over time. This is to be expected in a dynamic field situation.
b) mis-classification tended to lead to agglomeration of adjoining territories which were otherwise identified more or less correctly, rather than total misinterpretation of the badger spatial structure. The implication of this is that, while reactive culling operations have targeted the "correct" badger social groups, a proportion may also have captured neighbouring groups. Thus trapping efficiency is unlikely to have been greatly affected, although some of the epidemiological data will have been compromised. Ongoing molecular genetic work will help identify circumstances where this has occurred.
4. We support the Auditors' recommendation for a more extensive approach to surveying, with areas being surveyed only when several adjoining properties have been signed up, and with maps being continually re-evaluated through the surveying process. The adoption of Geographical Information Systems (GIS) to amalgamate survey maps for each trial area should facilitate this process. We particularly support the Auditors' recommendation that staff be encouraged to identify "possible main setts", as long as field staff make a final decision on sett classification when they have completed surveying of a particular area. We do not, however, concur with the Auditors' recommendation that a more complex sett classification be adopted, since its value for analytical purposes is unclear.
5. We are reassured by the Auditors' finding that the SOP, if correctly implemented, can generate accurate territory borders. We clearly support the Auditors' recommendation that SOPs should be adhered to but also recognise that during the period audited SOPs were undergoing re-evaluation and change. We are satisfied that SOPs are now being adhered to and believe that the introduction of GIS, which can be used to generate Dirichlet tessellation's automatically, has facilitated this process. MAFF staff have received further training in territory delineation since the maps supplied to the Auditors were produced.
6. We note the Auditors' concern about the definition of barriers to badger movement. Additional guidance will be written into the SOP.
7. We are grateful for and welcome the Auditors' report and are reassured that field operative procedures have now been improved by MAFF in the light of experience gained and that further staff training has taken place. Nonetheless we agree the need for further auditing in this area, particularly where outside contractors are involved in survey work. We, therefore, support MAFF's decision to reappoint auditors.
Independent Scientific Group on TB in cattle
January 2001
Page last modified:
12 August 2003
Page published: 5 February 2003