Effectiveness of African wild dog (Lycaon pictus) re-introductions in South Africa. (systematic review)
Our ability to evaluate the effectiveness of conservation interventions is primarily reliant on and often limited by the available evidence. As claimed conservation success (or failure) might merely be an artefact of the quantitative approach used for evaluation, both in terms of locating and analysing data, cross-validation of results may be important. We thus re-evaluated the effectiveness of African wild dog (Lycaon pictus) re-introductions in South Africa using a systematic review approach, which included comprehensive data searching and meta-analysis not employed in the original assessment.
The objective of this study was to cross-validate the management recommendations of a previous evaluation of an endangered species recovery programme using a systematic review approach.
Data on the survival of re-introduced wild dogs and their offspring as well as on covariates potentially impacting survival were available from all wild dog re- introductions and translocations known to have been attempted in South Africa since 1995. To assess whether any additional survival data existed, relevant people and organisations involved in wild dog re-introductions and translocations were contacted, and literature databases and internet search engines were searched using keywords.
References captured by the above search were deemed relevant if all of the following were present: subject (African wild dog or Lycaon pictus), intervention (re- introduction or translocation) and outcome of interest (qualitative or quantitative reporting of re-introduction success). As in the original assessment, 40 covariates that vary among re-introduction sites and release events were identified as potential factors that may explain heterogeneity in the survival of re-introduced wild dogs.
Data collection and analysis
Raw data on survival and covariates potentially impacting survival were extracted from the original assessment. Meta-analysis of outcome measures (i.e. survival rates) was used to generate effect sizes via analysis of risk ratios based on a modified Cohen’s g metric. Univariate random effects meta-regression for all categorical and continuous covariates was used to examine heterogeneity in the survival of re- introduced wild dogs.
The original dataset was confirmed to be complete by an exhaustive search to locate additional data. Both evaluations suggested that wild dog re-introductions are successful in the short-term, with high survival rates of the released animals and their offspring. The meta-analysis of all the available evidence corroborated the importance of pre-release socialisation in promoting post-release survival at the pack level. In contrast, the original assessment found additional covariates affect the survival of re- introduced wild dogs at the individual level.
The available evidence suggests that wild dog re-introductions in South Africa are an effective conservation tool, the success of which is largely determined by pre-release socialisation. This study emphasises the importance of cross-validating management recommendations in endangered species recovery programmes with different quantitative methods to assess and communicate the reliability of results.
The African wild dog (Lycaon pictus) is an intensely social species in danger of extinction if nothing is done to halt its decline (Woodroffe et al. 2004). In South Africa, in an effort to restore wild dog numbers in increasingly fragmented landscapes and to complement the single viable population occurring in Kruger National Park, a plan was launched to manage separate sub-populations of wild dogs in several small, geographically isolated conservation areas as a single meta-population (Mills ef al. 1998). This intensive management approach involves the re-introduction of wild dogs into suitable conservation areas, and periodic translocations among them to mimic natural dispersal and maintain gene flow.
This conservation strategy is largely based upon expert opinion (Wild Dog Advisory Group of South Africa — WAG-SA) and there has been no predictive framework available to quantify which re-introduction techniques are the most efficient, despite the initial failures and high costs associated with wild dog re-introductions and translocations. Consequently, Gusset et al. (2007) sought to elucidate those factors that have affected the survival of re- introduced wild dogs and their offspring, with survival of and breeding by the release generation being a pragmatic criterion for short-term re-introduction success (Seddon 1999). Using an information-theoretic approach, known-fate modelling in program MARK was employed to estimate the survival of re-introduced wild dogs and their offspring, and to model covariate effects relative to survival. Survival analysis revealed that the determinants of re-introduction success can be reduced to two factors relevant for management, suggesting that wild dog re-introductions should be attempted with socially integrated animals that are released into securely fenced areas.
What remains unclear, however, is how the statistical approach used affected the outcome of the evaluation. Several factors hypothesized by experts to impact survival were found not to have an effect, including controversial interventions such as vaccination and predator control, whereas expensive measures such as fencing and pre-release socialization had a positive impact on survival. Using a systematic review approach, we propose to re-evaluate the determinants of re-introduction success in this actively managed meta- population of wild dogs in South Africa, which represents one of the most extensive efforts to date to re-introduce an endangered species.