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 |
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).
- 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:
- ‘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.
- ‘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.
- ‘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.
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.
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 .
- 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.
- An assessment of factors which may have contributed to the
patterning of status change across these sites.
- Establishment of a program capable of being a core component of
ongoing biodiversity monitoring in the savannas, which is
consistent across jurisdictions.
- Through a set of detailed autecological studies of individual
species, an assessment of responses of mammals to variation in land
management regimes.
- Development of guidelines for management which will better
provide for sustainability and maintenance of landscape
health.
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
