Kate
Reardon-Smith (PhD candidate):
|
Australian Centre for
Sustainable Catchments |
 |
Research
Title:
Disturbance ecology in the riparian woodlands of
the Upper Condamine Floodplain, southern Queensland
Supervisors:
Dr Andy Le Brocque (Faculty of Sciences, USQ), Dr Alan House (CSIRO Sustainable Ecosystems)
Description:
Eucalypt woodlands associated with the floodplain sections of the
Condamine River are widely recognised as being in generally poor
condition, with evidence of significant dieback coupled with limited
recruitment of canopy species, and the incursion of invasive weed
species. Incremental decline in these communities has obvious
implications for ecosystem function, aquatic and terrestrial
biodiversity, and landscape amenity.
This research investigates the condition (health and function) of
Eucalyptus tereticornis/E. camaldulensis riparian woodland
communities of the Condamine floodplain in relation to a number of
prevailing natural and anthropogenic disturbance factors (e.g. climate
variability, spatial and temporal changes in land- and water-use,
grazing, weed invasion) operating at a number of scales (landscape-,
patch- and population-scale). It takes a multi-dimensional approach
aimed at developing an integrated understanding of the drivers and
mechanisms of ecosystem decline in these environments, with key
components of the research including assessment of current riparian
woodland composition and condition, and investigations of the roles of
herbivory, competition and facilitation within the context of altered
disturbance regimes.
The core studies in this research are:
-
a survey of Eucalyptus tereticornis / camaldulensis
riparian woodland community floristic composition and condition
across 27 sites on the upper Condamine floodplain between Pratten
and Dalby;
-
a soil-seedbank germination trial, based on samples collected from
the 27 survey sites;
-
an investigation of the influence of arboreal herbivores (koalas and
brush-tailed possums) on tree condition using banded (to exclude
arboreal mammals) and unbanded tree pairs (established in 2000) at 4
sites within the study area; and
-
experimental field trials (conducted at St Ruth Reserve)
investigating the competitive success of the introduced weed,
Phyla canescens (lippia or ‘condamine couch’) and
vegetation community responses to the presence and removal of lippia.
These include investigations of lippia abundance in
response to resource (light, nutrient, moisture) and competition
gradients along transects (n = 12) running from mature trees to more
open areas, and of ground-cover species’ (including lippia)
responses to grazing and lippia removal (6 treatments applied in a
completely randomised block design; n = 8)
Results
of these studies will be assessed within the context of prevailing
disturbance regimes and interpreted in terms of the potential for
significant change in ecosystem composition and function in these
woodlands using the state and transition conceptual framework
For more information
contact:
Ms Kate Reardon-Smith,
Australian Centre for
Sustainable Catchments/Faculty of Sciences
University of Southern
Queensland, Toowoomba, Queensland 4350 AUSTRALIA
ph.: 07 4631 5445
| email:
reardons@usq.edu.au
|
