GIS-based tools for management of pine plantations, Queensland, Australia

Two examples of GIS-based multiple-criteria evaluations of plantation forests are presented. These desktop assessments use available topographical, geological and pedological information to establish the risk of occurrence of certain environmentally detrimental processes. The first case study is concerned with the risk that chemical additives (i.e. simazine) applied within the forestry landscape may reach the drainage system. The second case study assesses the vulnerability of forested areas to landslides. The subject of the first multiple-criteria evaluation (MCE) was a 4 km2 logging area, which had been recently site-prepared for a Pinus plantation. The criteria considered relevant to the assessment were proximity to creeks, slope, soil depth to the restrictive layer (i.e. potential depth to a perched water table) and soil erodability (based on clay content). The output of the MCE was in accordance with field observations, showing that this approach has the potential to provide management support by highlighting areas vulnerable to waterlogging, which in turn can trigger overland flow and export of pollutants to the local stream network. The subject of the second evaluation was an Araucaria plantation which is prone to landslips during heavy rain. The parameters included in the assessment were drainage system, the slope of the terrain and geological features such as rocks and structures. A good correlation between the MCE results and field observations was found, suggesting that this GIS approach is useful for the assessment of natural hazards. Multiple-criteria evaluations are highly flexible as they can be designed in either vector or raster format, depending on the type of available data. Although tested on specific areas, the MCEs presented here can be easily used elsewhere and assist both management intervention and the protection of the adjacent environment by assessing the vulnerability of the forest landscape to either introduced chemicals or natural hazards.

Predictive modelling to aid the regional-scale management of a vertebrate pest

Extensive resources are allocated to managing vertebrate pests, yet spatial understanding of pest threats, and how they respond to management, is limited at the regional scale where much decision-making is undertaken. We provide regional-scale spatial models and management guidance for European rabbits (Oryctolagus cuniculus) in a 260,791 km(2) region in Australia by determining habitat suitability, habitat susceptibility and the effects of the primary rabbit management options (barrier fence, shooting and baiting and warren ripping) or changing predation or disease control levels. A participatory modelling approach was used to develop a Bayesian network which captured the main drivers of suitability and spread, which in turn was linked spatially to develop high resolution risk maps. Policy-makers, rabbit managers and technical experts were responsible for defining the questions the model needed to address, and for subsequently developing and parameterising the model. Habitat suitability was determined by conditions required for warren-building and by above-ground requirements, such as food and harbour, and habitat susceptibility by the distance from current distributions, habitat suitability, and the costs of traversing habitats of different quality. At least one-third of the region had a high probability of being highly suitable (support high rabbit densities), with the model supported by validation. Habitat susceptibility was largely restricted by the current known rabbit distribution. Warren ripping was the most effective control option as warrens were considered essential for rabbit persistence. The anticipated increase in disease resistance was predicted to increase the probability of moderately suitable habitat becoming highly suitable, but not increase the at-risk area. We demonstrate that it is possible to build spatial models to guide regional-level management of vertebrate pests which use the best available knowledge and capture fine spatial-scale processes.

Biodiversity, biosecurity and integrated pest management

Breaches of biosecurity, leading to incursions by invasive species, have the potential to cause substantial economic, social and environmental losses, including drastic reduction in biodiversity. It is argued that improving biosecurity reduces risk to biodiversity, while maintaining stable ecosystems through biodiversity can be a safeguard against biosecurity breaches. The global costs of invasive alien species (IAS) have been estimated at around US$350 billion, while alien invertebrate and vertebrate pests and weeds are estimated to cost Australia at least $7 billion a year. A striking, current, example is the incursion by Myrtle Rust (Puccinia psidii) an organism which can infect all members of the Myrtaceae, the most important family in the Australian flora. Myrtle rust was first detected on a property on the central coast of New South Wales in late April 2010. Two years later the disease has been detected in numerous locations in Queensland and New South Wales ranging from commercial plant nurseries and public amenities to large areas of bushland. This particular breach of biosecurity will, inevitably, diminish biodiversity of flora and fauna over large areas of the continent. Integrated pest management (IPM), an enrichment of diversity in managing invasive and other pest species, offers the best opportunity to address problems such as these. Australia's response to increasing biosecurity risk is comprehensive and includes national networking of scientists engaged in a complex program of biosecurity research and development, including studies of IPM. This network is being enhanced by the development of international linkages.