Use of diet and body condition assessments as intermediate indicators of translocation success in the Critically Endangered Philippine crocodile (<scp><i>Crocodylus mindorensis</i></scp>)

Brown, Joseph; Shirley, Matthew H.; Yog-yog, Amante; Weerd, M. van; Balbas, M.G.; Tarun, Bernard A.; Siler, Cameron D.

doi:10.1002/aqc.3700

Cited by 5 publications

(6 citation statements)

References 55 publications

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“…(2006) found that 32.1% of juvenile falcons ( Falco peregrinus ) dispersed prematurely and Brown et al. (2021) found up to 92.7% of subadult crocodiles ( Crocodylus mindorensis ) released could not be recaptured in the study area.…”

Section: Resultsmentioning

confidence: 84%

“…All returned to their source location within 1 month (Read et al., 2007). When releasing subadult crocodiles ( Crocodylus mindorensis ), up to 92.7% released were unable to be recaptured from the study area, likely due to a combination of hyperdispersal, mortality, and trap avoidance following release (Brown et al., 2021).…”

Section: Resultsmentioning

confidence: 99%

“…All 4 translocated juveniles (100%) dispersed compared with only 2 of the 6 wild juveniles (33.3%) (Kinley & Newhouse, 2008). Dzialak et al (2006) found that 32.1% of juvenile falcons (Falco peregrinus) dispersed prematurely and Brown et al (2021) found up to 92.7% of subadult crocodiles (Crocodylus mindorensis) released could not be recaptured in the study area.…”

Section: Cohort Demographics and Hyperdispersalmentioning

confidence: 91%

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Review of hyperdispersal in wildlife translocations

Bilby

Moseby

2023

Conservation Biology

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Species translocation is a common tool to reverse biodiversity loss, but it has a high failure rate. One factor that contributes to failure is postrelease hyperdispersal, which we define as the long‐distance movement of individuals resulting in their failure to contribute to population establishment. We reviewed reported incidences of hyperdispersal and compared rates of hyperdispersal among taxa, population demographics, release cohorts, and success of mitigation techniques. Of 151 conservation translocations (reinforcements and reintroductions) in which animals were tracked, hyperdispersal was confirmed in 52.1% of programs. The prevalence of hyperdispersal (percentage of studies) was relatively consistent across taxa (42.9–60%), but hyperdispersal rates in birds were likely underestimated because 76.9% of bird translocations showed incidences in which birds could not be located after release, but hyperdispersal was unable to be confirmed. Eutherians exhibited a higher average incidence of hyperdispersal (percentage of hyperdispersing individuals in a cohort) of 20.2% than birds, reptiles, and marsupials (10.4%, 15.7%, and 10.3%, respectively). No significant trends were observed for sex, source population, or translocation type, but there were nonsignificant trends for males to hyperdisperse more than females and for higher incidences of hyperdispersal in reinforcements relative to reintroduction programs. Mitigation techniques included temporary confinement, supplementation of resources, and releasing animals in social groups, but only half of studies examining mitigation techniques found them useful. Hyperdispersal incidence was variable within taxa, and we advise against forming translocations strategies based on results from other species. Hyperdispersal is a significant welfare, economic, and conservation issue in translocations, and we suggest definitions, reporting, and experimental strategies to address it.

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Section: Cohort Demographics and Hyperdispersalmentioning

confidence: 91%

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Review of hyperdispersal in wildlife translocations

Bilby

Moseby

2023

Conservation Biology

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“…Given the scale of ONE, and the behavioural, morphological and evolutionary consequences on inappropriate captive rearing protocols (Alberts 2007; Passos et al 2017; Brown et al 2021) the natural kiwi chick diets, and their region-specific nutritional needs should become a research priority. It is known that when species are nutritionally mis-matched to their optimal, dynamic, natural diet, individuals can over- or under-investment in life history traits, especially those associated directly with adult fitness (Lee et al 2008; Solon-Biet et al 2015; Gray et al 2018).…”

Section: Discussionmentioning

confidence: 99%

Opportunity nest egg: insights on the nutritional ecology, life history and captive management of three species of kiwi (Apteryxspp.) chick from Operation Nest Egg zoo hand-rearing records

Gray,

Mitchell,

Milner-Bradford

et al. 2023

Preprint

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Zoo data collected by keepers while looking after endangered species are increasingly recognised as important scientific resources. As chicks, New Zealand’s threatened kiwi (Apteryxspp.) are subject to the protective conservation programme Operation Nest Egg (ONE), during which growth, developmental and life history data are recorded. We have conducted comparative analyses on hand rearing records from 306 chicks, from Coromandel, Eastern and Western populations of Brown kiwi (A. mantelli), and rowi (A. rowi) and Haast tokoeka (A. australis“Haast”). We analysed chick responses to an old dietvs. a new kiwi diet, introduced in 2017. Both diets are fixed nutrient ratio mixtures. The old diet was high-protein, low-energy, while the new diet is high-fat, high-energy, with better micronutrient levels. We found Coromandel chicks, who originate from the environmentally variable Kūaotunu Peninsula, grow the most efficiently overall on either diet, indicating they may be nutritional generalists. Western and Eastern chicks’ growth efficiency was intermediate, while the South Island species grew the least efficiently on either diet.Rowi chicks developed the fastest overall on either diet, while Haast tokoeka chicks developed the most slowly, especially on the new diet. Rowi chicks therefore had to eat large volumes of either diet over a short time to maintain their rapid development, while Haast chicks were required to eat large volumes, especially of the new diet, over a protracted developmental period. This situation may have led South Island chicks to over-consume one or another diet component, with likely health consequences. Neither diet was obviously superior for chick wellbeing overall, though the new diet better supported chicks that needed hand feeding. This work demonstrates different genetic populations of kiwi differ in their physiological responses to nutrition. As ONE is ongoing, tailored diets for chicks from each genetic group should be developed, and we present methods to achieve this. In our life history trait analyses, we found chick starting size (hatch mass) did not significantly influence growth efficiency across kiwi genetic group, nor did chick sex. We identified that chicks malpositioned as embryos were more likely to require extended periods of hand feeding, and that Eastern males produce more malpositioned embryos than other populations. Our study shows that effective zoo records can be used to improve captive care, to stimulate future research to refine species management practices, and to explore fundamental questions of life history evolution in wild and captive populations.

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“…An understanding of dietary requirements is important for translocation planning and monitoring. For example, an understanding of diet was important for assessing the post-release dietary similarity of translocated versus resident crocodilians as a measure of translocation success in the critically endangered Philippine crocodile (Crocodylus mindorensis [120]). This was a useful alternative to fecundity as an assessment measure due to the long lifespan of the species that would require decades of monitoring data using conventional analysis of reproductive success [120].…”

Section: Looking Forwardmentioning

confidence: 99%

Ecological Considerations When Designing Mitigation Translocations: An Australian Reptile Case Study

Bradley

Craig

Tomlinson

et al. 2023

Animals

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Translocation science has made considerable progress over the last two decades; however, reptile translocations still frequently fail around the world. Major knowledge gaps surround the basic ecology of reptile species, including basic factors such as habitat preference, which have a critical influence on translocation success. The western spiny-tailed skink (Egernia stokesii badia) is used here as a case study to exemplify how empirical research can directly inform on-ground management and future translocation planning. A combination of studies, including LiDAR scanning of microhabitat structures, camera trapping, plasticine replica model experiments and unbounded point count surveys to assess predation risk, and visual and DNA analysis of dietary requirements, were all used to better understand the ecological requirements of E. s. badia. We found that the skinks have specific log pile requirements, both native and non-native predator management requirements, and a largely herbivorous, broad diet, which all influence translocation site selection and management planning. The use of E. s. badia as an Australian case study provides a clear strategic framework for the targeted research of meaningful ecological factors that influence translocation decision-making. Similar approaches applied to other reptile species are likely to fundamentally increase the capacity for effective management, and the likelihood of future successful translocations.

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Use of diet and body condition assessments as intermediate indicators of translocation success in the Critically Endangered Philippine crocodile (Crocodylus mindorensis)

Cited by 5 publications

References 55 publications

Review of hyperdispersal in wildlife translocations

Review of hyperdispersal in wildlife translocations

Opportunity nest egg: insights on the nutritional ecology, life history and captive management of three species of kiwi (Apteryxspp.) chick from Operation Nest Egg zoo hand-rearing records

Ecological Considerations When Designing Mitigation Translocations: An Australian Reptile Case Study

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