Project 4 - Small Terrestrial Vertebrates: Clarifying Taxonomic Status

4.1: Investigation of the 'original' mammal fauna of eastern and southern Australia

Challenges

Information on the 'original' mammal fauna (i.e. that present at the time of European settlement) comes from two main sources:

1. museum specimens collected during the early historic period; and
2. bones found in caves or in other sedimentary contexts (e.g. recent sand dunes).

The largest samples often come from caves where owls have roosted over many generations, the bones of their prey deposited in regurgitated pellets or 'casts'. Archaeological sites often also produce valuable collections of mammal bones, in this case the remains of human prey.

There has been little prior work on the 'original' mammal fauna of eastern Australia and collections are not yet available from many areas. Although prior collections are available from several regions of Victoria, work on this material is now 30 years old and needs to be revised in the light of more recent developments in mammal taxonomy. More recent work, focused on parts of southern Australia, has been conducted by collaborators at the South Australian and Western Australian Museums.

Another major challenge for this sub-project is to recover DNA from early historic and prehistoric specimens. This is necessary both to complement morphology-based taxonomies, and as a means of making genetic comparison between surviving populations and those that have declined to extinction.

Seeking solutions

Our goal is to document the 'original' mammal fauna of eastern and southern Australia, with some degree of coverage for the major biogeographic regions. Greater priority is being given to areas where:

1. many mammals were originally named on the basis of early historic collections;
2. virtually nothing of the 'original' small mammal fauna has survived; and/or
3. there is a major contemporary conservation investment that would benefit from improved knowledge of the 'original' mammal fauna.

Approaches

Our two main sources of material are museum specimens (historic collections and bones in palaeontological and archaeological collections) and previously uncollected cave deposits. The latter are particularly numerous in areas of limestone karst and sandstone with cavernous weathering. Cavers and people studying cave fauna such as bats often have detailed local knowledge of suitable caves, and in many areas good bone deposits can be located with minimal effort.

The approximate age of bone deposits can often be assessed on geomorphic criteria and from the state of preservation of the remains. In some cases, where the age of a specimen is particularly important, it is generally possible (though costly) to obtain a direct estimate of age through a radio-carbon (C14) determination. Archaeological deposits often have independent C14 dating of charcoal or other organic material and this can give a broad indication of the age of associated animal remains.

DNA begins to deteriorate soon after death and undergoes progressive degradation over time, even in the best environment. Cave deposits are often a good environment for DNA preservation on account of the relatively stable temperature and we have successfully recovered ancient DNA from bones and teeth from a variety of caves in several different climatic zones within Australia. The Australian Centre for Ancient DNA at University of Adelaide is a state-of-the-art facility where small quantities of highly fragmented ancient DNA can be extracted and amplified without introducing modern contaminants.

Collaboration

Our major collaborators on this sub-project are researchers at the South Australian Museum (Dr Graham Medlin and Mr Matt McDowell) and the Western Australian Museum (Dr Alex Baynes) who have been investigating the original mammal fauna of southern Australia. They have amassed significant collections from several highly relevant areas and possess a high level of expertise on the identification and interpretation of these assemblages.

Tools for Decision Makers

This sub-project will generate regionally specific information that will be invaluable for decision making across numerous aspects mammal conservation, including captive breeding programs, reintroduction activities, and field surveys. Because of the immediate importance of these results, we intend to present the data as they become available, using web-based delivery and provide flexible tools that allow managers to access information in the format that they need.

Publications will focus on the taxonomic findings, and any issues of wider national or international interest (e.g. new insights into the timing and reasons for declines; implications for climate change scenarios).