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Strategic Red Fox control on bushfire affected public land in Victoria Black Saturday Victoria 2009 – Natural values fire recovery program
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... Occasionally, the aim of fox control programs is short-term protection of conservation assets that are susceptible to fox predation at certain periods in their life history, e.g. freshwater turtles when nesting, Malleefowl when nesting, migratory seabirds when present (Kirkwood et al. 2000;Robley et al. 2016a), or ecosystems after significant fire events (Robley et al. 2012). While implementing fox control to protect conservation assets would seem logical, foxes are a highly mobile species (Larivière and Pasitschniak-Arts 1996;Hradsky et al. 2017) and will rapidly invade newly vacated territories following small isolated control efforts (Newsome et al. 2014). ...
A study into the efficacy of publicly funded fox control programs across Victoria, Australia.
We found an wide variety of temporal and spatial baiting approaches are used in fox control programs across Victoria. Our modelling indicated that programs that are likely to achieve greater levels of reduction in fox density are characterised by consistent and frequent baiting over relatively large areas with good spatial coverage of baits. Programs that were less likely to achieve substantial reductions were characterised by relatively low numbers of bait stations, small control areas, and short term and infrequent baiting. We explored some alternative management strategies where modelling indicated low levels of reduction in fox density, and provide recommendations for the types of baiting operations which might improve reductions for different sized fox control programs.
... Poison baiting for foxes is already being applied or recommended as an emergency post-fire protection response for numerous threatened species across Australia, including Gilbert's potoroo, Potorous gilbertii, southern brown bandicoot, mountain pygmy possum, Burramys parvus, and brush-tailed phascogale, Phascogale tapoatafa (DSE 2005;Robley et al. 2012;DPW 2016;DENR 2017). At present, however, these programs vary greatly in baited area, duration and post-fire timing, and few robust data about their effectiveness have been published. ...
Inappropriate fire regimes and predation by introduced species each pose a major threat to Australia’s native mammals. They also potentially interact, an issue that is likely to be contributing to the ongoing collapse of native mammal communities across Australia. In the present review, I first describe the mechanisms through which fire could create predation pinch points, exacerbating the impacts of predators, including red foxes, Vulpes vulpes, and feral cats, Felis catus, on their native mammalian prey. These mechanisms include a localised increase in predator activity (a numerically mediated pathway) and higher predator hunting success after fire (a functionally moderated pathway), which could both increase native mammal mortality and limit population recovery in fire-affected landscapes. Evidence for such interactions is growing, although largely based on unreplicated experiments. Improving native mammal resilience to fire in predator-invaded landscapes requires addressing two key questions: how can the impacts of introduced predators on native mammals in fire-affected areas be reduced; and, does a reduction in predation by introduced species result in higher native mammal survival and population recovery after fire? I then examine potential management options for reducing predator impacts post-fire. The most feasible are landscape-scale predator control and the manipulation of fire regimes to create patchy fire scars. However, robust field experiments with adequate statistical power are required to assess the effectiveness of these approaches and preclude null (e.g. compensatory mortality) or adverse (e.g. mesopredator or competitor release) outcomes. Ongoing predator management and prescribed burning programs provide an opportunity to learn through replicated natural experiments as well as experimental manipulations. Standardised reporting protocols and cross-jurisdiction monitoring programs would help achieve necessary spatial and environmental replication, while multi-trophic, spatially explicit simulation models could help synthesise findings from disparate study designs, predict management outcomes and generate new hypotheses. Such approaches will be key to improving management of the complex mechanisms that drive threatened native mammal populations in Australia’s predator-invaded, fire-prone landscapes.
Accurate and reliable monitoring is necessary for effective management of threatened species in New Zealand. Mark-recapture studies are a powerful tool for conservation managers, and can be used in any situation where animals can be marked (or otherwise identified) and detected later by capture or sighting. In addition to estimating population size and survival rates, mark-recapture methods can be used to evaluate impacts of threats on survival, record population trends, collect information for population viability analyses, set performance targets against which responses to management can be measured, and highlight areas where further research is necessary. This report has three main sections. The first section introduces the basic principles of mark-recapture methodology that conservation managers need to understand to design effective mark-recapture studies. In the second section, specific guidelines for estimating abundance, survival and population growth rates are provided. We show which methods are appropriate for different situations, how field studies should be designed to avoid violating assumptions of mark-recapture methods, and how to get started on analysing the data. In the final section, we review a case study involving long-tailed bats (Chalinolobus tuberculatus), and use this to illustrate some problems that may be encountered in mark-recapture studies.
We report the development and application of a method using domestic dogs (Canis familiaris Linnaeus, 1758) to systematically locate wildlife scat over large remote areas. Detection dogs are chosen for their strong object orientation, high play drive, and willingness to strive for a reward. Dogs were trained to detect grizzly bear (Ursus arctos Linnaeus, 1758) and black bear (Ursus americanus Pallas, 1780) scats over a 5200-km2 area of the Yellowhead Ecosystem, Alberta, Canada. DNA from scat provided the species and (for grizzly bears only) sex and individual identities of the animal at each location. Concentrations of fecal cortisol and progesterone metabolites from these same grizzly bear scats provided indices of physiological stress and reproductive activity (in females), respectively. Black and grizzly bears were most concentrated in the northern portion of the multiuse study area, where food is most abundant yet poaching-related mortality appears to be heaviest. Physiologic stress was also lowest and female reproductive activity correspondingly highest for grizzly bears in the north. The scat-based distributions corresponded to concurrently collected hair-snag data in 1999 and global positioning system radiotelemetry data (of grizzly bears) in 1999 and 2001. Results suggest that the scat dog detection methodology provides a promising tool for addressing a variety of management and research questions in the wildlife sciences.
Determination of the relative abundance of two populations, separated by time or space, is of interest in many ecological situations. We focus on two estimators of relative abundance, which assume that the probability that an individual is detected at least once in the survey is either equal or unequal for the two populations. We present three methods for incorporating the collected information into our inference. The first method, proposed previously, is a traditional hypothesis test for evidence that detection probabilities are unequal. However, we feel that, a priori, it is more likely that detection probabilities are actually different; hence, the burden of proof should be shifted, requiring evidence that detection probabilities are practically equivalent. The second method we present, equivalence testing, is one approach to doing so. Third, we suggest that model averaging could be used by combining the two estimators according to derived model weights. These differing approaches are applied to a mark-recapture experiment on Nuttall's cottontail rabbit (Sylvilagus nuttallii) conducted in central Oregon during 1974 and 1975, which has been previously analyzed by other authors.
Identification of individuals in a free-ranging animal population is potentially hampered by a lack of distinguishing features (e.g., scars, unique color patterns), poor visibility (e.g., densely forested environments), cost and invasiveness of physical capture, and mark loss. Advances in DNA-analysis technology offer alternative methods of individual identification that may overcome several of these problems. We investigated the genetic variability of American black bears (Ursus americanus) and brown (grizzly) bears (Ursus arctos) in the Columbia River basin of British Columbia, Canada, and developed a method to obtain genetic samples from free-ranging bears. We established the background genetic variability using microsatellite genotyping at 9 loci using tissue and blood samples from captured bears. In 3 field trials, we tested methods to obtain hair from free-ranging bears. Although all methods collected hair suitable for DNA analysis, the barbed-wire enclosure hair-trap was superior. We extracted DNA from hair roots and identified sample species with a species-specific mitochondrial DNA (mtDNA) test and sample sex from a Y-chromosome test. Using 6 microsatellite loci from nuclear DNA (nDNA), we screened all hair samples for individual identity and developed match probability functions based on scenarios of random sampling (P(random)), the likely presence of parent-offspring groupings in the samples (P(par-offs)), and the likely presence of siblings in the samples (P(sib)). We applied the P(sib) to each hair sample (match criteria at P(sib)<0.05) and illustrated how these microsatellite genotypes can be used as genetic tags in mark recapture bear censuses. The ability to identify species, sex, and individuality of free-ranging bears has numerous potential applications in field studies.
The Lincoln-Petersen model (Chapter 2) and closed population models (Chapter 3) are presented briefly. The Jolly-Seber open population model is covered in detail in Chapter 4. In Chapter 5, the authors consider the "enumeration' or "calendar of captures' approach, which is widely used by mammalogists and other vertebrate ecologists, and recommend that it be abandoned in favor of analyses based on the Jolly-Seber model. One restricted version of the Jolly-Seber model, which allows losses (mortality or emigration) but not additions (births or immigration), is likely to be useful in practice. Another series of restrictive models requires the assumptions of a constant survival rate or a constant survival rate and a constant capture rate for the duration of the study. In Chapter 5, the authors consider 2 generalizations of the Jolly-Seber model. The temporary trap response model allows newly marked animals to have different survival and capture rates for 1 period. The other generalization is the cohort Jolly-Seber model. Ideally all animals would be marked as young, and age effects considered by using the Jolly-Seber model on each cohort separately. Chapter 6 presents a detailed description of an age-dependent Jolly-Seber model, which can be used when ≥2 identifiable age classes are marked. Detailed description of the "robust' design is given in Chapter 7, in which each primary period contains several secondary sampling periods. Chapter 8 gives detailed discussion of the design of capture-recapture studies. A new program has been written to accompany the material on the Jolly-Seber model (Chapter 4) and its extensions (Chapter 5). Another new program has been written for a special case of the age-dependent model (Chapter 6) where there are only 2 age classes. In Chapter 9 a description of the different versions of the 2 programs is given. Chapter 10 gives a description of some alternative approaches that were not considered in this monograph. -from Authors
We compared survey techniques for estimating relative and absolute abun-dances of swift foxes (Vulpes velox) in New Mexico. For relative abundance surveys, the most efficient technique is collection of scats followed by verification of species depositing scats with DNA analysis. By collecting scats, the proportions of individual locations where swift foxes were detected were 61.9% and 67.7% during surveys in 2000 and 2001, which were greater than the proportions using scent stations (31.4%, 47.1%) or trapping (11.5%, 8.4%). By collecting scats, we detected swift foxes in 100% of the fox home ranges within the study area. If scent-station surveys are used instead, scent-station transects consisting of stations spaced at 1.6 km (1.0 mile) intervals and operated for three nights are the most practical. Searching for tracks, spotlighting and calling are much less efficient techniques. For absolute abundance surveys, trapping and resighting with cameras at bait stations was more accurate than counting unique microsatellite DNA genotypes from collected scats. Using trapping/resighting, we estimated the 95% confidence intervals for the swift fox population within the study area to be 17.March 2001, respectively. We counted 63 and 27 unique genotypes in early 2000 and 2001, respectively. The numbers of unique genotypes, which were much greater than population estimates obtained from trap-ping and resighting, were overestimated because of the presence of transient swift foxes and poor quality DNA from scats leading to allelic drop-out and/or false alleles.