Evaluating translocation success is essential for wildlife management and conservation; short‐term success can be evaluated by analysing settlement behaviour after release. We analysed GPS collar ...data from 47 white (Ceratotherimum simum simum, Burchell, 1817) and 25 black (Diceros bicornis minor, Drummond, 1876) rhinoceros translocated to the Okavango Delta in Botswana between 2014 and 2018. We tested for effects of age and sex on site fidelity and compared movement ranges after translocations between different release sites and between newly released and established individuals. White rhinoceros adults displayed higher site fidelity than subadults and males higher than females. Adults may therefore be better translocation candidates. Site fidelity of black rhinoceros did not differ between sexes or ages. Established rhinoceros movement ranges were smaller than those of newly released ones, pointing towards extended post‐translocation exploratory movements and later settlement in smaller home ranges. Movement ranges of white rhinoceros released on an island were significantly smaller than others, which shows together with annual home range sizes compared with the literature that reserve size and rhinoceros density affect home range size. All rhinoceros in this study survived for more than 1‐year post‐translocation, so these translocations can be deemed successful in the short term.
Résumé
L'évaluation du succès d'une translocation est essentielle pour la gestion et la conservation de la faune sauvage. Le succès à court terme peut être évalué en analysant le comportement de l’établissement sur site après la libération. Nous avons analysé les données des colliers GPS de 47 rhinocéros blancs (Ceratotherimum simum simum, Burchell, 1817) et 25 rhinocéros noirs (Diceros bicornis minor, Drummond, 1876) transloqués dans le delta de l'Okavango au Botswana entre 2014 et 2018. Nous avons testé les effets de l'âge et du sexe sur la fidélité au site et comparé les domaines de mouvement après les translocations entre différents sites de relâchement et entre les individus nouvellement relâchés et les individus établis. Les rhinocéros blancs adultes ont affiché une fidélité au site plus élevée que les subadultes et les mâles plus élevée que les femelles. Les adultes pourraient donc être de meilleurs candidats à la translocation. La fidélité au site des rhinocéros noirs ne différait pas entre les sexes ou les âges. Les domaines de mouvement des rhinocéros établis étaient plus petits que ceux des rhinocéros nouvellement relâchés, ce qui indique des mouvements exploratoires prolongés après les translocations et un établissement ultérieur dans des domaines vitaux plus petits. Les domaines de déplacement des rhinocéros blancs relâchés sur une île étaient significativement plus petits que les autres, ce qui montre, avec la taille des domaines vitaux annuels, en comparaison avec la littérature, que la taille des réserves et la densité des rhinocéros affectent la taille des domaines vitaux. Tous les rhinocéros de cette étude ont survécu pendant plus d'un an après leur translocation, de sorte que ces translocations peuvent être considérés comme un succès à court terme.
Conservation translocations (reintroductions, reinforcements, ecological replacements, and assisted colonization) have played a vital and necessary role in conserving endangered species and ...ecosystems. Yet concerns over potential unintended ecological consequences frequently hinder the progress of translocation activities. We reviewed the history of U.S. translocations to ask: how often were intended benefits the result versus harmful unintended consequences? We found that translocations played a key role in recovery for 30% (14 of 47) of U.S. delisted taxa. Translocations have been performed, are planned, or are part of continuing recovery actions for 70% (1,112 of 1,580) of listed threatened and endangered taxa. Of the 1,014 total taxa we found with recorded conservation translocations spanning 125 years, we found only one restricted instance that caused a loss of biodiversity. All other reports of negative consequences were caused by translocations performed for economic and cultural interests in the absence of conservation‐based governance. Examples included fish stocking for sport and biological control programs for agricultural pests. We included biological control programs in this analysis because they can be and often are used as conservation tools, to directly benefit ecosystems. In addition, they are often raised as examples of harmful unintended results during the conservation planning process. However, only 1.4% (42) of 3,014 biological control agents released globally have caused ecosystem‐level deleterious impacts. All of these were initially released before the 1980s and conservation‐based practice and governance in recent decades have reduced off‐target impacts from biological control practice. Two themes emerged from our review: (a) conservation translocations routinely yielded their intended benefits without producing unintended harm, and (b) when ecological damage did occur, it was in the absence of conservation practice and regulation. This evidence shows that well‐planned translocation efforts produce ecosystem benefits, which should be weighed against the costs of inaction when deliberating conservation strategies.
Reintroduction programs can benefit from optimisation of source populations to maximise genetic diversity. Here, we report an approach to guide genetic supplementation of founder individuals to ...maximise genetic diversity in a reintroduction program for a nationally threatened Australian ground-dwelling marsupial, the southern brown bandicoot (eastern subspecies),
Isoodon obesulus obesulus
. Following local extinction ~ 100 years earlier, founding individuals were reintroduced to Booderee National Park in south-eastern Australia over three years from the nearest viable wild population, approximately 250 km to the south. To assess and manage risks associated with low genetic diversity, we measured genetic diversity of the reintroduced population relative to the diversity across the subspecies’ range. The genetic diversity of the initial founder population was comparable with other sampled populations; most likely because the source population had high genetic diversity relative to other locations. We simulated scenarios of supplementation of the founder population from alternative candidate sources. We identified populations in the Melbourne region of Victoria as those that would yield the greatest increase in genetic diversity in the Booderee population. The simulated increase in diversity resulting from supplementation was accurately predicted by the pairwise F
ST
comparison between the candidate and recipient population, but not diversity of the supplementation source itself. Genetic diversity is an important consideration in reintroductions; our study enables managers to make informed decisions to maximise the long-term persistence and genetic diversity of reintroduced populations.
One of the primary goals of conservation translocation programs should be the maintenance of both population demographic stability and genetic diversity. Here, we provide genetic management ...recommendations to inform a population reinforcement of the declining Egyptian Vulture population in the Balkans. Specifically, we examined whether the number of released individuals is sufficient to prevent genetic diversity loss due to random genetic drift and what the origin of the individuals should be that comprise the captive breeding pool. To this aim, we estimated and assessed genetic diversity levels and genetic structure of Egyptian Vulture populations across much of the species’ range using both neutral and non-neutral candidate loci involved in migration. We then evaluated the effects of the currently proposed population management scheme and candidate source populations on retaining allelic diversity. Our results show low differentiation values among populations and absence of genetic structure which point to past high gene flow. Furthermore, there was no predicted significant impact of different source populations on the genetic diversity of the recipient Balkan population. We also found that the declining Egyptian Vulture population in the Balkans still retains high levels of genetic diversity and therefore genetic diversity restoration is not currently needed. However, without any management, diversity is likely to decrease fast because of increased genetic drift as the population size continues to decline. Population reinforcement with nine birds per year for 20 years would provide sufficient demographic support for the population to retain > 85% of rare allelic diversity. Birds originating from the Balkans would ensure ecological and behavioral similarity and thus would be the best option for reinforcement. Nevertheless, our results demonstrate that to prevent further population contraction and loss of adaptive alleles, releasing individuals of different origin would also be appropriate.
Translocations using captive-reared and wild-caught animals are important and widely used conservation tools to boost dwindling endangered populations and for maintaining biodiversity, but still ...suffer high failure rates. Animal personality, defined as consistent inter-individual differences in behaviour, can have a critical influence on individual fitness and population dynamics. Many conservation translocations could benefit by selecting individuals with certain personality traits, but the importance of personality of the ‘founders’ is often not considered. The link between behavioural assessments and improving translocation success therefore needs further investigation to demonstrate that adopting behavioural assays for translocations is worthwhile and feasible. Too few studies have considered the effect of captive-rearing or novel release-site conditions on changes to pre-release behavioural structural characteristics, including such as between-trait (i.e., behavioural syndromes) or within-trait correlations (i.e., personality-plasticity correlations) among individuals. Considering that appropriate behavioural structures can usually serve as immediate adaptive responses to environmental uncertainty, we suggest that the loss of appropriate structures may give a partial explanation for why captive-reared or wild-caught animals unfamiliar with the release-site environment suffer high post-release mortality rates. We call for more comprehensive personality trait assessments to evaluate the potential negative effects on behavioural structure induced by captive rearing and an unfamiliarity to the release-site environment in future conservation studies. We suggest several specific measures that may help to reform appropriate behavioural structures during captive rearing to form part of future feasibility and pre-release stages of conservation translocations.
Success rates for conservation translocations of species are low and there is a need for increased understanding of how this activity is best applied. Here, using static species distribution models ...and a spatially-explicit dynamic simulation model, RangeShifter, we examine the impacts of habitat cover in recipient landscapes, allocation of individuals into multiple sites and species trait characteristics on the long-term fate of hypothetical translocations of a grassland specialist butterfly, Maniola jurtina, in Finland. While persistence of populations introduced to climatically suitable locations northwards of the current range can be increased by selecting sites with increasing habitat cover and by allocation of individuals to multiple release sites, local population growth rate is shown to be the key parameter in determining likely translocation success. We conclude that the long-term persistence of translocated habitat specialist butterflies, particularly with low growth rates, appears to be uncertain in modern-day fragmented grassland networks and that translocation activities should prioritize management that improves local growth rate.
•Dynamic population models are useful for assessing the success of translocations.•Habitat loss hinders establishment of translocated grassland specialist butterflies.•Persistence may be enhanced by increasing habitat cover and population growth rate.•Allocation of individuals to multiple release sites improves population persistence.•Modelling tools aid in avoiding management options with low likelihoods of success.
Griffon Vulture (Gyps fulvus) populations occur on Mediterranean islands, where wind energy is developing fast. As griffons are subjected to collisions with wind turbines while foraging, it is ...necessary to understand which factors affect their movements to minimize the potential impact of wind farms. We assessed habitat use of 37 griffons (n. GPS locations = 130,218) and their overlap with wind farms in Sardinia (Italy), an island where both Griffon Vulture population and wind energy are significantly expanding. Griffons in Sardinia cover smaller areas (95% isopleth = 956.3 ± 677.7 km2, 50% isopleth = 73.8 ± 48.2 km2) than in mainland Europe, restricting most of their movements within 5–10 km from colonies and roosts. Supplementary feeding stations throughout these areas (n = 37) provide approximately 20 tons of carrion each year, suggesting that griffon movements are strongly determined by food availability. Overall, 6 wind farms (101 turbines) out of the 29 present in Sardinia were built in areas used by foraging griffons. Two of them were positioned near roosts and supplementary feeding stations. As griffon movements concentrate around nesting/roosting sites and feeding stations, wind farms should be excluded around these highly utilized areas, and mitigation measures, including the removal of livestock carrion, should be adopted for those that are built at greater distances. There is also an urgent need for updated data about wind energy location. The creation of supplementary feeding stations could be used to shape the enlargement of the foraging grounds of an increasing Griffon Vulture population on Mediterranean islands and to exclude wind farm areas to mitigate their impacts.
Translocations are becoming increasingly common although the effectiveness of this conservation tool for amphibians is highly variable. We reviewed ten translocations of Leiopelma frogs occurring ...between 1924 and 2016. Data were gathered on factors which may have influenced translocation outcomes. Results at each location were measured against an established four-step framework for stages of success: survival of individuals, reproduction, population growth, and population viability. Three conservation translocations and two mitigation translocations were considered to have failed, indicated by no or low survival of founders or lack of evidence of reproduction within a reasonable timeframe. Causes of failure include invasive predators at the release site, small founder numbers, homing, and poor habitat quality. The remaining five translocations were considered either successful (meeting all four stages of success), or on the road to success (meeting at least the first two stages of success). Successful translocations included predator control, total release of more than 70 founders, and in some cases adaptive management to address management decisions over time. Our findings emphasise the need for long-term post-release monitoring (> 25 years) to determine translocation success for K-selected species. Better, cost-effective, methods for monitoring population growth and population viability are required for Leiopelma frogs. Improvements could be made in open access reporting of methods and decision-making, disease risk analysis and stakeholder engagement. Further, improving our knowledge of what makes high quality Leiopelma habitat would help to objectively assess potential future translocation sites. Future translocations should consider the impacts of predicted global climate change; assisted migration may be required in the future. Translocations are a risky conservation strategy, so should only be undertaken with good cause, quality planning, and sufficient long-term resources for monitoring and management. Any future translocations for Leiopelma, whether motivated by conservation or mitigation, should follow best practice guidelines and use evidence-based decision-making to maximise outcomes.
Freshwater mussel populations are in sharp decline and are considered to be one of the most imperilled groups globally. Consequently, the number of captive breeding programmes has increased rapidly ...in recent years, coupled with subsequent reintroductions/population reinforcements to reverse these declines. The outcomes of mussel conservation translocations are seldom reported in the primary literature, hindering opportunities for learning and for population recovery at pace. Here, we describe the methods employed to carry out a successful conservation translocation of the freshwater pearl mussel (Margaritifera margaritifera) in a declining population in northwest England. Following a small-scale pilot release in 2017, four release sites were identified for a population reinforcement of over 1300 tagged mussels in 2021. Monitoring during 2022 showed high levels of retention of juveniles at three out of the four release sites, despite the occurrence of a significant flood event during October 2021. Subsequent releases of 1100 juveniles were carried out across the three successful sites in 2023. Ongoing and regular monitoring is essential in order to provide data on the longer-term fate of propagated juveniles in the wild. This will allow for adaptive management of release activities in this river. These data will be useful to design conservation translocation strategies for other imperilled pearl mussel populations in the UK and throughout Europe.
Captive breeding is often a last resort management option in the conservation of endangered species which can in turn lead to increased risk of inbreeding depression and loss of genetic diversity. ...Thus, recording breeding events via studbook for the purpose of estimating relatedness, and facilitating mating pair selection to minimize inbreeding, is common practice. However, as founder relatedness is often unknown, loss of genetic variation and inbreeding cannot be entirely avoided. Molecular genotyping is slowly being adopted in captive breeding programs, however achieving sufficient resolution can be challenging in small, low diversity, populations. Here, we evaluate the success of the Vancouver Island marmot (
Marmota vancouverensis
; VIM; among the worlds most endangered mammals) captive breeding program in preventing inbreeding and maintaining genetic diversity. We explored the use of high-throughput amplicon sequencing of microsatellite regions to assay greater genetic variation in both captive and wild populations than traditional length-based fragment analysis. Contrary to other studies, this method did not considerably increase diversity estimates, suggesting: (1) that the technique does not universally improve resolution, and (2) VIM have exceedingly low diversity. Studbook estimates of pairwise relatedness and inbreeding in the current population were weakly, but positively, correlated to molecular estimates. Thus, current studbooks are moderately effective at predicting genetic similarity when founder relatedness is known. Finally, we found that captive and wild populations did not differ in allelic frequencies, and conservation efforts to maintain diversity have been successful with no significant decrease in diversity over the last three generations.
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