Tropical Savannas CRC > Research > CRC Research 2001-2008 > Conservation > Mammal status in northern Australia

Mammal status in northern Australia

Leader: John Woinarski, Parks and Wildlife Commission of the Northern Territory, Darwin

Full title: Biodiversity on the fault lines: examination of mammal decline across northern Australia, and implications for management
Project 1.2.2.

Summary | Objectives | Approach and methods | Links | Outputs | Project team |

Summary

A range of evidence suggests that currently, mammals comprise the major loss of biodiversity in the tropical savannas. This project seeks to assess changes in that fauna, broadly across northern Australia. A fundamental tenet of the TS–CRC is to retain and/or restore landscape health across the savanna. This will never be realised if a major component of the biodiversity is disappearing from the lands.

The main approach is by repeat of earlier landmark surveys, analysis of change and then relating such change to a set of possible causal factors (altered fire regimes, grazing, disease, exotic predators). This broad-brush approach is supplemented by some targeted studies of individual species which may be representative of general trends. Management priorities will be derived from these studies.

This project was developed originally following results of work from the previous CRC, mostly in the Northern Territory. Extension to the two other northern jurisdictions is in line with the CRC perspective of cross-jurisdictional projects. The need for such extension to the Kimberley was underlined by a recent Australian-wide review of the conservation status of the mammal fauna:

“Equivalent changes have been observed in the North Kimberley where all ground-dwelling CWR mammal records during the last two decades have come from the northwestern fringe of the region, less than 20 km from its coast. Over the last 30 years this region has suffered massive changes in vegetation composition and structure due to increased fire frequency and the recent arrival of large exotic herbivores that have now penetrated to the coast. If this change is not halted and reversed, we expect that some of the region’s mammals will become extinct, while others will persist only on islands. The ‘top end’ of the Northern Territory and the North Kimberley have been considered to be refugia for a range of mammal species—this belief appears to be false” (McKenzie and Burbidge 2002).

Objectives

  • to provide a quantified assessment of changes in the native mammal fauna at a representative set of sites across northern Australia;
  • to provide an assessment of the timing and rate of such change, and particularly whether the change is ongoing;
  • to relate any change to possible causal factors;
  • to derive and provide management advice, in order that landholders can implement optimal management for the retention of biodiversity.

This project addresses several key CRC objectives:

  1. ‘That the CRC will provide up-to-date and scientifically sound information to underpin management of the tropical savannas for sustainable use and conservation’ as it focuses directly on providing information to assess sustainability, and from which to derive management principles which aim to improve sustainability.
  2. ‘That the CRC facilitates better management by conducting research in participation with tropical savanna stakeholders’ by undertaking collaborative research with park managers and, where appropriate, Aboriginal landholders.
  3. ‘That the CRC produces management options, along with assessments of their benefits and costs’ by development of outputs which provide recommendations for land management which will be most likely to retain the native mammal fauna of the savannas.

Approach and methods

The broad approach of this study is to revisit and resample sites from which detailed information on mammal abundance was previously collected. Such sites include areas within Cape York Peninsula, Dalrymple Shire, Emerald Shire (Qld.), Kakadu and Cobourg Peninsula (NT), and Mitchell Plateau, Prince Regent, Drysdale, Dampier Peninsula and Kimberley islands (WA). We anticipate re-visiting most of these over the course of the two-year period 2002–04.

There are some unavoidable constraints with the comparison of current and previous results, mostly relating to the imprecision in methodology of the earlier work compared to the more quantified and standardised survey protocols now used. In general, we will attempt to replicate the original sampling procedure, and simultaneously also use more repeatable systematic procedures, which would provide a better baseline for future comparisons.

Any changes will be related to patterns of land use, fire history and other factors, where possible using generalised linear modelling (as described in our recent report on re-sampling the mammal fauna of Kakadu NP: Woinarski et al. 2002).

In addition to these re-samples, we will focus on two mammal species (the antilopine wallaroo in Queensland and the brush-tailed tree-rat in the Northern Territory) and one mammal group (rock wallabies in north-eastern Qld) considered representative of the pattern of decline. These first two of these studies will be conducted as PhD projects, and will examine pattern of change and factors related to status in far more detail than that possible in the broad-brush re-surveys described above. The rock-wallaby study will be conducted by QPWS.

Links

The project links related work occurring across the three jurisdictions, and across three state conservation agencies (CALM, PWCNT and QEPA) and two of the CRC partner universities (JCU and CDU).

This project also includes a small funding component to a PhD study being undertaken on the Australian bustard in northern Australia. Although obviously not a mammal, the pattern of decline in this large bird species closely parallels that of mammals, and the research will consider many of the same possible causative factors.

Where appropriate, this project will link with Project 2.3.3 Aboriginal ethnoecological studies , and Project 1.2.3 Biodiversity monitoring .

Outputs

  1. An assessment of the pattern of loss (magnitude, species affected, timing) of mammals at contrasting representative sites across the savannas, with sites chosen largely on the criterion of historic landmark surveys.
  2. An assessment of factors which may have contributed to the patterning of status change across these sites.
  3. Establishment of a program capable of being a core component of ongoing biodiversity monitoring in the savannas, which is consistent across jurisdictions.
  4. Through a set of detailed autecological studies of individual species, an assessment of responses of mammals to variation in land management regimes.
  5. Development of guidelines for management which will better provide for sustainability and maintenance of landscape health.

Project team

John Woinarski, PWCNT
Craig Hempel, PWCNT
Martin Armstrong, PWCNT
Jenni Risler, PWCNT
Tony Start, CALM
Norm McKenzie, CALM
Andrew Burbidge, CALM
Keith Morris, CALM
Chris Done, CALM
Four technical officers, CALM
Peter Latch, QPWS
One technical officer, QPWS
Peter Johnson, QPWS
John Winter, QPWS
Juliana McCosker, QPWS
Chris Johnson, JCU
Andrew Krokenberger, JCU
Ron Firth, CDU
Michelle Watson, CDU
Euan Ritchie, JCU
Mark Zimbieki, Adelaide University

Contacts

Dr John Woinarski
NT Dept Natural Resourcs, Environment, the Arts and Sport
Tel: 08 8995 5000

Fax: 08 8995 5099

PO Box 496
PALMERSTON, NT 0831