The effects of fire and mining on lizard communities

1
The effects of fire and mining on lizard
communities
Kellie Goodhew, Department of Biological and
Physical Sciences, University of Southern
Queensland, Australia
Introduction Vegetation structure is important in
determining the composition of lizard faunas1.
When a disturbance alters the composition and
structure of vegetation, the composition of
lizard faunas is likely to be affected. After a
fire disturbance, a sequential colonisation by
lizards occurs with the regenerating vegetation.
A larger scale disturbance, such as mining may be
expected to impact more on lizard composition due
to the greater alteration of vegetation structure
and composition. The aim of this study is to
determine if the succession of lizard species
following sand-mining is related to that
following fire.
Results Two lizard species were common in the
unmined forests Lampropholis delicata
(Scincidae) and Lampropholis guichenoti (Fig 2).
Two lizard species were common in sand-mined
areas Ctenotus robustus (Scincidae) (Fig 3) and
Ctenotus taeniolatus (Fig 1). As shown in Figure
4 the abundance of each common lizard species
changed with time since mining. As well the
pattern of abundance was different for each
species with time since mining (Fig 4). Within
post-fire forested sites there were more
L.guichenoti and L.delicata than C.robustus and
C.taeniolatus (Fig 5). Forest sites differed to
mined sites and had significantly more canopy
cover, more litter cover, a taller understorey
and more dense and less patchy vegetation below
50cm.
Figure 1. Ctenotus taeniolatus
Methods The study was conducted within the Tomago
Sandbeds (3252S, 15145E), New South Wales.
Sites were located in open forest on the tops of
sand dunes or in areas with similar vegetation
type before sand-mining. Sites were affected by
fire or mining before the study at 4, 8 and 14
years previously. Lizards were trapped for two
5-day periods in the present study. Data was
pooled with previous years sand-mining data to
produce a longer chronosequence of times since
sand-mining. Pitfall traps consisted of four 10L
plastic buckets and one central 20L plastic
bucket. Traps were checked twice a day. The
physical characteristics and vegetation structure
of each site were recorded. Two-factor ANOVA and
Three-factor ANOVA were used to analyse the data
with lizard species and time since disturbance as
factors. A principal components factor analysis
was performed on the habitat variables of
forested and mined sites.
Figure 2. Lampropholis species
Figure 5. Mean number or individual lizard
species per day of trapping (/- SE) at different
tines since fire or mining
Discussion The results show that mineral
sand-mining has significantly altered the lizard
fauna. There is a clear sequence of changes in
the most abundant lizard species from 4 to 20
years post-mining. This indicates that it takes
more than 20 years for lizard faunas to return to
levels found in unmined forests. The changes in
lizard fauna in post-fire forest sites were less
pronounced than the changes that occurred for the
same period post-mining. There was no clear
succession in forest sites disturbed by fire.
The changes in lizard faunas are not entirely
due to time since disturbance. The difference in
vegetation structure and litter cover between
forest and mined sites may have contributed to
changes.
Figure 3. Ctenotus robustus
Conclusion Sand-mining significantly alters the
abundance of lizard species from
Lampropholis-dominated to Ctenotus-dominated.
The return of lizard species to sand-mined areas
is a longer process of succession compared with
that following fire. The study has found that
the common scincid lizards of the coastal dune
systems follow a predictable succession after a
disturbance and this may be related to vegetation
structure and ground cover.

• References
• Pianka E.R. (1989) Desert lizard diversity
  Additional comments and some data. Am. Nat. 134,
  344-64.

Acknowledgement Adapted from Taylor, J.E. and
Fox, B.J. (2001) Disturbance effects from fire
and mining produce different lizard communities
in eastern Australian forests. Austral Ecology.
26 193-204.
Figure 4. Succession of the four most abundant
lizard species on sand-mined areas. Abundance
(mean /- SE) versus time since mining (years).
Completed as part of BIO3314 Terrestrial Ecology
assessment - October, 2003