The Validation of Novel Ecological Survey Methods for Use in Describing Harvest Mouse Micromys minutus Autecology

  • Emily Howard-Williams

Student thesis: Doctoral Thesis

Abstract

According to much of the literature relating to Micromys minutus (harvest mouse) the species has historically presented many challenges to researchers, particularly when attempting to collect sufficient data to describe their ecology, life history and responses to the ever-increasing threat of habitat loss and fragmentation. Methodological improvements are needed which provide sufficient species-specific data to underpin conservation and which are of sufficient quality to allow their movement ecology to be quantified. Here two novel methods were developed and tested, which included remote scent surveys using a detection dog and Radio Frequency Identification (RFID) trapping. After validation, RFID trapping was then used to quantify M. minutus movement in fragmented habitats. A preliminary study was carried out which assessed the ability of a dog to be trained to indicate the scent of M. minutus. Here positive reinforcement training methods were used and the dog’s effectiveness was evaluated in a training environment using scent samples collected from controlled and uncontrolled situations. Secondly, RFID trap effectiveness was compared to the results of live trapping. Data were maximised by releasing individually tagged M. minutus into a suitable semi-natural enclosure on the Moulton College estate. After validation a further release was undertaken to investigate M. minutus movement ecology. Here gaps of differing widths were incorporated into the release enclosures and movements between the habitat patches were measured. Individuals included in each release cohort were exposed to an Open Field Test prior to release, and thus, their behaviour in relation to trapping and movement was also assessed. There is strong evidence that a dog can be trained to detect M. minutus and discriminate their scent from other sympatric nontarget species in a controlled training environment. When applied to uncontrolled field situations, the remote scent survey proved more effective than nest search surveys by volunteers during the autumn months, providing preliminary evidence that olfactory indicators could be more efficient than visual clues when establishing presence of M. minutus. Additional validation in uncontrolled settings is still required. Encouraging results were also seen during validation of the use of RFID trapping with better results in terms of raw trapping rates over live trapping being observed. Furthermore, findings indicate that M. minutus have sufficient navigational and motion capacity to successfully move over gaps ≤2m, but gaps greater than 2m could limit their movement with possible implications for population persistence. The findings also suggest that individuals that explore more slowly may have an advantage when inhabiting a fragmented habitat. Thus, movement propensity is likely to be an individual behavioural trait and may vary across situations; this provides a novel perspective on their conservation and may support conservation decisions being based on behaviour rather than density. The data collected for this thesis demonstrates that progress has been made in terms of monitoring M. minutus and the findings presented are entirely novel for this species. Nevertheless, they remain a challenging species and more questions have been asked than can be answered within the thesis. However, the sum of this work has provided a clear direction for future research on M. minutus.
Date of Award2019
Original languageEnglish
SupervisorDuncan McCollin (Supervisor), James Littlemore (Supervisor) & Wanda McCormick (Supervisor)

Cite this

The Validation of Novel Ecological Survey Methods for Use in Describing Harvest Mouse Micromys minutus Autecology
Howard-Williams, E. (Author). 2019

Student thesis: Doctoral Thesis