I.W. Wright

Bio: I.W. Wright is an academic researcher. The author has contributed to research in topics: Precautionary principle & Population. The author has an hindex of 2, co-authored 3 publications receiving 272 citations.

The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field experiment.

Abstract: The hypothesis that predation by feral cats and introduced foxes reduces population sizes of small, native vertebrates was supported by results of a predator-removal experiment at Heirisson Prong, a semi-arid site in Western Australia. The methods of control used against cats and foxes to protect native mammals reintroduced to Heirisson Prong produced three broad ‘predator zones’: a low-cat and low-fox zone, where foxes were eradicated and spotlight counts of cats declined after intensive cat control; a high-cat and low-fox zone where spotlight counts of cats increased three-fold after foxes were controlled; and a zone where numbers of cats and foxes were not manipulated. Small mammals and reptiles were monitored for one year before and three years after predator control began. Captures of small mammals increased in the low-cat and low-fox zone, but where only foxes were controlled captures of small mammals declined by 80%. In the absence of cat and fox control, captures of small mammals were variable over the sampling period, lower than where both cats and foxes were controlled, yet higher than where only foxes were controlled. The capture success of reptiles did not appear to be related to changes in predator counts. This study presents the first experimental evidence from mainland Australia that feral cats can have a negative impact on populations of small mammals.

Towards scientific contributions in applying the precautionary principle: an example from southwestern Australia

Abstract: Scientific suspicion of the widely stated precautionary principle is based largely on confusion as to procedures for incorporating scientific data into a philosophical-political process. Here we take published guidelines on applying the precautionary principle and illustrate how they allow scientific input to the question of whether or not current multiple-use forestry takes a precautionary approach to conserving threatened or vulnerable marsupials in the jarrah forest of Western Australia. The scientific input involves (i) identification of outcomes in similar situations elsewhere in Australia, (ii) selection of indicator species for monitoring based on predictions made on the basis of (i) above and published accounts of the species' biology, and (iii) a prescription for monitoring/experimentation that includes a quantitative requirement for a probability of detecting impacts based on statistical power analysis. On the standards suggested, contemporary management falls short of a quantitative definition of precaution that involves adherence to measurable standards.

Conserving Forest Biodiversity: A Comprehensive Multiscaled Approach

Abstract: While most efforts at biodiversity conservation have focused primarily on protected areas and reserves, the unprotected lands surrounding those areas - the "matrix" - are equally important to preserving global biodiversity and maintaining forest health. In this volume, leading forest scientists David B. Lindenmayer and Jerry F. Franklin argue that the conservation of forest biodiversity requires a comprehensive and multiscaled approach that includes both reserve and non-reserve areas. They lay the foundations for such a strategy, bringing together the latest scientific information on landscape ecology, forestry, conservation biology, and related disciplines as they examine: the importance of the matrix in key areas of ecology such as metapopulation dynamics, habitat fragmentation, and landscape connectivity; general principles for matrix management; using natural disturbance regimes to guide human disturbance; landscape-level and stand-level elements of matrix management; the role of adaptive management and monitoring; and social dimensions and tensions in implementing matrix-based forest management.

Complex interactions among mammalian carnivores in Australia, and their implications for wildlife management

Abstract: Mammalian carnivore populations are often intensively managed, either because the carnivore in question is endangered, or because it is viewed as a pest and is subjected to control measures, or both. Most management programmes treat carnivore species in isolation. However, there is a large and emerging body of evidence to demonstrate that populations of different carnivores interact with each other in a variety of complex ways. Thus, the removal or introduction of predators to or from a system can often affect other species in ways that are difficult to predict. Wildlife managers must consider such interactions when planning predator control programmes. Integrated predator control will require a greater understanding of the complex relationships between species. In many parts of the world, sympatric species of carnivores have coexisted over an evolutionary time scale so that niche differentiation has occurred, and competition is difficult to observe. Australia has experienced numerous introductions during the past 200 years, including those of the red fox (Vulpes vulpes) and the feral cat (Felis catus). These species now exist in sympatry with native mammalian predators, providing ecologists with the opportunity to study their interactions without the confounding effects of coevolution. Despite an increasing body of observational evidence for complex interactions among native and introduced predators in Australia, few studies have attempted to clarify these relationships experimentally, and the interactions remain largely unacknowledged. A greater understanding of these interactions would provide ecologists and wildlife managers world-wide with the ability to construct robust predictive models of carnivore communities, and to identify their broader effects on ecosystem functioning. We suggest that future research should focus on controlled and replicated predator removal or addition experiments. The dingo (Canis lupus dingo), as a likely keystone species, should be a particular focus of attention.

The impacts and management of foxes Vulpes vulpes in Australia

Abstract: 1. The successful introduction of the red fox Vulpes vulpes into Australia in the 1870s has had dramatic and deleterious impacts on both native fauna and agricultural production. Historical accounts detail how the arrival of foxes in many areas coincided with the local demise of native fauna. Recent analyses suggest that native fauna can be successfully reintroduced to their former ranges only if foxes have been controlled, and several replicated removal experiments have confirmed that foxes are the major agents of extirpation of native fauna. Predation is the primary cause of losses, but competition and transmission of disease may be important for some species. 2. In agricultural landscapes, fox predation on lambs can cause losses of 1–30%; variation is due to flock size, health and management, as well as differences in the timing and duration of lambing and the density of foxes. 3. Fox control measures include trapping, shooting, den fumigation and exclusion fencing; baiting using the toxin 1080 is the most commonly employed method. Depending on the baiting strategy, habitat and area covered, baiting can reduce fox activity by 50–97%. We review patterns of baiting in a large sheep-grazing region in central New South Wales, and propose guidelines to increase landholder awareness of baiting strategies, to concentrate and coordinate bait use, and to maximize the cost-effectiveness of baiting programs. 4. The variable reduction in fox density within the baited area, together with the ability of the fox to recolonize rapidly, suggest that current baiting practices in eastern Australia are often ineffective, and that reforms are required. These might include increasing landholder awareness and involvement in group control programs, and the use of more efficient broadscale techniques, such as aerial baiting.