Date of Award

2001

Degree Type

Thesis

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Communications, Health and Science

First Advisor

Dr Mark Lund

Second Advisor

Dr Dorian Moro

Abstract

The Heath Mouse (Pseutlomys shortridgei) was formerly widely distributed in Western Australia and Victoria. However, now it is known only to exist in areasof fragmented habitat. Heath Mouse populations have not been investigated in Western Australia, as it was thought to be extinct in the state until its rediscovery in 1987. It is known from only tour locations, and from these, the highest numbers known are probably the 18 captures of this mouse from five years of trapping in Lake Magenta Nature Reserve. Given the few numbers of Heath Mice, the purpose of this study was to identify habitat characteristics associated with the presence of heath mice in Lake Magenta Nature Reserve and use this to predict other suitable habitat areas within the reserve, in order to find additional populations. There were three components to the study: habitat sampling, mapping and modelling of habitat, and prediction testing. From the records of 15 mice captures, five presence and five absence sites were selected. Habitat parameters including floristics, structure, soil and topography were recorded at each site. From multivariate analysis, vegetation communities were derived, based on floristic data. Ninety-three percent of P. shortridgei captures (14 out of 15) were associated with the identified Mixed Laterite Community, and the remaining 7% were associated with the Open Shrub Mallee over Eremaea Scrub community. Criteria were established for identifying this community type in the field. Given that the majority of P. shortridgei captures were associated with the Mixed Laterite community, two methods were used to predict other areas in the reserve with this community type. Firstly, areas were identified from aerial photograph interpretation, and secondly, by a predictive modelling technique based on satellite imagery data. To determine the accuracy of these models for identifying suitable P. shortridgei habitat, ground truthing was used. Ten sites from each of these maps were selected in the field and scored for their level of accuracy in determining suitable P. shortridgei habitat, based on established criteria. Areas identified by aerial photograph interpretation were found to be the most suitable habitat, having an average score of250 out of a possible 300. Trapping grids were set in two locations within predicted areas in the reserve to test for the presence of P. shortridgei in predicted areas. Each 5 x 5 grid consisted of 25 Elliott and 25 Cage traps. Pseudomys shortridgei was recorded in one of the predicted grids and 150m from the other. By locating an additional individual in an area predicted by the methods used, it is likely that the maps would provide a good basis for focusing future trapping efforts within the reserve to areas most likely to contain Heath Mice. The use of this method is applicable for locating additional populations of P. shortridgei in surrounding nature reserves in the wheatbelt. This study is just the first step in contributing to the development of a conservation program for P. shortridgei in Western Australia. As little is known of the populations existing in fragmented wheatbelt reserves, identifying suitable habitat has shown to be a successful approach in finding additional populations. However. there are always a number of factors affecting small mammal distribution and abundance, providing a good basis for future research.

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