Ecological factors affecting the foraging behaviour of Xerus rutilus

The African unstriped ground squirrel (Xerus rutilus) is widely dispersed across various habitats in East Africa and hence encounters a diverse suite of predators and plant communities. It is not known how different habitats and plant characteristics affect the foraging behaviour of X. rutilus. We used giving-up densities (GUDs) as a measure of foraging efficiency to explore the foraging costs of environmental heterogeneity. To determine foraging efficiency across spatial scales, we established food patches in two microhabitats (open and cover), which were nested within three habitats (koppie, edge and bushland). When foraging in a cover microhabitat, foraging efficiency decreased away from the koppie, but when in the open microhabitat, foraging efficiency was lowest near the koppie edge. Second, to determine foraging efficiency with common plant toxins, we presented the squirrels with seeds soaked in either tannic acid, oxalic acid or distilled water (control). Foraging efficiency did not differ between tannic-treated and control seeds, but oxalic-treated seeds had higher GUDs. Overall, our results suggest that X. rutilus is a remarkably efficient forager across multiple axes of environmental heterogeneity, which may have intriguing consequences for the ecological community.

Fire and its interaction with ecological processes in box-ironbark forests

Box-Ironbark forests extend across a swathe of northern Victoria on the inland side of the Great Dividing Range. Although extensively cleared and modified, they support a distinctive suite of plants and animals. Historical fire regimes in this ecosystem are largely unknown, as are the effects of fire on most of the biota. However, knowledge of the ecological attributes of plant species has been used to determine minimum and maximum tolerable fire intervals for this ecosystem to guide current fire management. Here, we consider the potential effects of planned fire in the context of major ecological drivers of the current box-ironbark forests: namely, the climate and physical environment; historical land clearing and fragmentation; and extractive land uses. We outline an experimental management and research project based on application of planned burns in different seasons (autumn, spring) and at different levels of burn cover (patchy, extensive). A range of ecological attributes will be monitored before and after burns to provide better understanding of the landscape-scale effects of fire in box-ironbark forests. Such integration of management and research is essential to address the many knowledge gaps in fire ecology, particularly in the context of massively increased levels of planned burning currently being implemented in Victoria.

Overcoming data constraints to create meaningful ecological models

Many techniques used to model ecosystems cannot be meaningfully applied to large-scale ecological problems due to data constraints. Disparate collection methods, data types and incomplete data sets, or limited theoretical understanding mean that a wide range of modelling techniques used to model physical processes or for problems specific to species or populations cannot be used at an ecosystem scale. In developing an ecological response model for the Coorong, a South Australian hypersaline estuary, we combined several flexible modelling approaches in a statistical framework to develop an approach we call ‘ecosystem states’. This model uses simulated hydrodynamic conditions as input to predict one of a suite of states per space and time, allowing prediction of likely ecological conditions under a variety of scenarios. Each ecosystem state has defined sets of biota and physico-chemical parameters. The existing model is limited in that its predictions have yet to be tested and, as yet, no spatial or temporal connectivity has been incorporated into simulated time series of ecosystem states. This approach can be used in a wide range of ecosystems, where enough data are available to model ecosystem states. We are in the process of applying the technique to a nearby lake system. This has been more difficult than for the Coorong as there is little overlap in the spatial and temporal coverage of biological data sets for that region. The approach is robust to low-quality biological data and missing environmental data, so should suit situations where community or management monitoring programs have occurred through time.

Ecological determinism in Australia : tracing the legacy of McHarg downunder and its key precedents

Ecological planning, as advocated by Ian McHarg, filtered extensively through North America following the publication of Design with Nature (1965). The integrated design and planning approach was also advanced by numerous graduates of McHarg's studios at the University of Pennsylvania where this approach was extensively trialled and proven. While a clear synthesis and theoretical framework was articulated and reinforced through a plethora of projects, monographs, and articles, the majority of these perspectives were North American, lacked clarity about the translation of the approach into legal strategic and statutory planning instruments, nor shed light upon what transpired in Australia. This paper reviews the development of the Conservation Plan created for the southern Mornington peninsula in Victoria, Australia, as well as its intent, structure and internal workings as a successful model of ecological statutory planning, in the context of the wider WPRPA activities that draws directly from the McHarg theory. Known as the Conservation Plan for the southern Mornington Peninsula in Victoria, a revolutionary planning structure devised in the early 1970s by several Australian proponents. The Conservation Plan continues in operation today curating a high scenic valued landscape protecting it from intrusion from the growing metropolitan city of Melbourne thus fulfilling its objectives of landscape quality conservation whilst still permitting sympathetic building and land use growth. Contextually, the Conservation Plan appears to be only statutory equivalent translation of the approach internationally other than the Pinelands Commission planning processes in New Jersey.