A Biosensor-Based Method for Non-invasively Monitoring Wildlife Reproduction - The Field Vole (Microtus agrestis) as a Potential Biomarker of Environmental Disruption

Environmental disturbance arising from human activity is known to adversely impact upon biodiversity in many different ways. The use of biomarkers offers an indirect means of detecting and monitoring broad non-specific exposure to one or more chemical pollutants; however, no biomarker for monitoring the effect of such disruption on terrestrial mammals has yet been validated. In response to the need for a cheap, simple, effective means for detecting environmental disturbance, we propose that monitoring fecundity within a small mammalian (short-tailed field vole, Microtus agrestis) population via non-invasive faecal steroid analysis may provide such a biomarker. In this paper, we present the validation of an enzyme-linked immunosorbent assay (ELISA) and biosensor system currently employed to monitor progesterone levels in bovine milk, for use with faecal extracts. Biosensor technology was found to offer a comparable (P < 0.01), novel and alternative means to traditional ELISA methodology for the measurement of progestagen levels in pregnant vole faecal samples, and as such it provides the potential for future use within the field as an aid to wildlife monitoring programmes.