The untamed shrew: on the termination of an eradication programme for an introduced species

Solow, Andrew R.; Seymour, Adrian S.; Beet, Andrew R.; Harris, Stephen

doi:10.1111/j.1365-2664.2007.01446.x

Cited by 27 publications

(30 citation statements)

References 15 publications

(18 reference statements)

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“…Detecting the final few individuals and/or demonstrating that there are no more individuals remaining are arguably the hardest parts of any eradication program. Thus developing techniques that allow eradication declaration without the reliance solely on the lack of physical observation is now a research focus for biotic invasions (Solow et al 2008;Rivadeneira et al 2009;Rout et al 2009). Prior personal experience with this species has already shown that small persisting populations are easily detected 2-3 month post-treatment, thereby allowing a sole reliance on visual assessment.…”

Section: Discussionmentioning

confidence: 98%

Eradication of populations of an invasive ant in northern Australia: successes, failures and lessons for management

Hoffmann

2011

Biodivers Conserv

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Eradication is the most difficult management goal for exotic species, and successes are rare and even more rarely published. The lack of publication of the methodology and outcomes of eradication programs severely limits the transfer of knowledge to programs elsewhere that target the same or similar species. Here I detail the successes and failures of eradication efforts on six populations of African big headed ant Pheidole megacephala in northern Australia, covering a combined area of almost 9 ha. Two years post-treatment, assessment criteria for successful eradication were met for four of the six populations, whereas eradication failed in the remaining two, resulting in the need for ongoing management. Positive outcomes are attributed to eight criteria being met: (1) a single line of project management authority; (2) over-arching legal authority; (3) susceptibility of the target organism to control procedures; (4) sufficient resources; (5) detectibility of the target organism at low densities; (6) early intervention; (7) prevention of reinvasion; and (8) prevention of invasive succession. Reasons for one of the failures remain unclear, but eradication failed in the other because a part of the population was not treated. In both cases, the eradication failures could have been detected and managed much earlier than was the case. The successes and lessons documented here, coupled with the now large number of small-scale eradications of this ant, warrant the implementation of larger and more ambitious management programs against this significant invader, especially within areas of high conservation value.

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Section: Discussionmentioning

confidence: 98%

Eradication of populations of an invasive ant in northern Australia: successes, failures and lessons for management

Hoffmann

2011

Biodivers Conserv

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“…If available data are more detailed than a presence–absence record, then methods that make use of this additional information (e.g. Solow et al . 2008) would be preferable.…”

Section: Discussionmentioning

confidence: 99%

Using sighting records to declare eradication of an invasive species

Rout¹,

Salomon

McCarthy

2009

Journal of Applied Ecology

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Summary 1.A major challenge for eradication managers is deciding when a programme can be deemed successful. Regan et al . (2006) were the first to pose this problem within a decision theory framework, minimizing the net expected cost of the decision. The optimal time to declare eradication was based on the number of consecutive surveys in which the species was not found ('absent surveys'). Their formulation used estimates of detectability and persistence -parameters that are often difficult to estimate -to calculate the probability that the invasive species is still present. 2.Here we use a similar decision-making framework but instead predict presence based on the pattern of sightings, using a method developed by Solow (1993a) that assumes a constant sighting rate. This method does not require estimates of detectability and persistence. We find the number of absent surveys after which eradication should be declared, using three approaches: a stochastic dynamic program, which finds the exact optimal solution, a rule of thumb, and an approximation. We then compare these results with a method assuming a declining sighting rate. 3. Both the rule of thumb and approximation give results that are close to the exact optimal solution. The rule of thumb with the declining sighting rate method generally gives a larger optimal number of absent surveys. 4. Synthesis and applications. Analysing this problem within a decision theory framework enables us to minimize the expected cost of declaring eradication. By using the more readily available sighting data, we make this framework applicable to a wider range of invasive species. Our approximation is a simple calculation, making it an accessible tool that could be applied by managers of eradication programmes for invasive species.

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“…These issues highlight the need for careful consideration of the assumptions underlying these methods, and the value of conducting simulations to experimentally test how robust the methods are to assumption violations. For example, these statistical methods may not be appropriate for evaluating eradiation programs as the sightings (e.g., trap captures) are not independent of the decline (see Solow et al, 2008 for an alternative method). While others (Burgman et al, 1995;McCarthy, 1998) have attempted to resolve questions over sighting effort, more work is needed in this area.…”

Section: Uniform Ppcc Field Significance Testmentioning

confidence: 99%

Goodness of Fit of Probability Distributions for Sightings as Species Approach Extinction

et al. 2009

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Estimating the probability that a species is extinct and the timing of extinctions is useful in biological fields ranging from paleoecology to conservation biology. Various statistical methods have been introduced to infer the time of extinction and extinction probability from a series of individual sightings. There is little evidence, however, as to which of these models provide adequate fit to actual sighting records. We use L-moment diagrams and probability plot correlation coefficient (PPCC) hypothesis tests to evaluate the goodness of fit of various probabilistic models to sighting data collected for a set of North American and Hawaiian bird populations that have either gone extinct, or are suspected of having gone extinct, during the past 150 years. For our data, the uniform, truncated exponential, and generalized Pareto models performed moderately well, but the Weibull model performed poorly. Of the acceptable models, the uniform distribution performed best based on PPCC goodness of fit comparisons and sequential Bonferroni-type tests. Further analyses using field significance tests suggest that although the uniform distribution is the best of those considered, additional work remains to evaluate the truncated exponential model more fully. The methods we present here provide a framework for evaluating subsequent models.

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The untamed shrew: on the termination of an eradication programme for an introduced species

Cited by 27 publications

References 15 publications

Eradication of populations of an invasive ant in northern Australia: successes, failures and lessons for management

Eradication of populations of an invasive ant in northern Australia: successes, failures and lessons for management

Using sighting records to declare eradication of an invasive species

Goodness of Fit of Probability Distributions for Sightings as Species Approach Extinction

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