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Mandl I, Houmadi A, Said I, Abdou BBA, Mohamed N, Fardane A, Soulaïmana S, Mohamed M, Anthoy M B, Doulton H. Seasonal trends and population status of the highly threatened Pteropus livingstonii in the Comoros archipelago. BMC Ecol Evol 2024; 24:64. [PMID: 38764016 PMCID: PMC11103843 DOI: 10.1186/s12862-024-02255-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 05/10/2024] [Indexed: 05/21/2024] Open
Abstract
Flying foxes of the genus Pteropus, especially those inhabiting islands, face increasing pressure from anthropogenic threats. A first step to implementing effective conservation actions is to establish monitoring projects to understand a species' population status and trend. Pteropus species are highly affected by seasonality which further requires regular, repeated, and long-term data to understand population trends, and reactions to severe weather events. In the present case study, a regular, bi-annual population census was implemented on Comoros between 2016 and 2023 for the highly threatened Livingstone's fruit bat, Pteropus livingstonii, and compared the results of standardized monitoring to historical population data. Seasonality had a large impact on the number of bats found at roost sites, with more bats present in the wet season, but the data over the past eight years revealed no significant in- or decrease in the number of bats counted on the island Anjouan. We estimated around 1,200-1,500 bats on Anjouan and 300-400 bats on Mohéli, and found that landcover type has no measurable effect on population distribution at roost sites. Our study highlights the need for long-term surveys to understand past population trends and that single counts are not sufficient to draw final conclusions of a species' status.
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Affiliation(s)
- Isabella Mandl
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
| | | | - Ishaka Said
- NGO Dahari, Hombo - Mutsamudu, Anjouan, Comoros
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Vanderduys EP, Caley P, McKeown A, Martin JM, Pavey C, Westcott D. Population trends in the vulnerable Grey-headed flying-fox, Pteropus poliocephalus; results from a long-term, range-wide study. PLoS One 2024; 19:e0298530. [PMID: 38512935 PMCID: PMC10956843 DOI: 10.1371/journal.pone.0298530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 01/25/2024] [Indexed: 03/23/2024] Open
Abstract
Monitoring is necessary for the management of any threatened species if its predicament and status are to improve. Monitoring establishes baseline data for tracking trends in distribution and abundance and is a key tool for informing threatened species management. Across much of the Old World, bats in the genus Pteropus (Pteropodidae, Chiroptera) face significant threats from habitat loss, conflict with humans, and hunting. Despite conflict with humans and their threatened status, few Pteropus are being monitored. Often, this is because of difficulties associated with their high mobility, large and easily disturbed aggregations, and their use of unknown or remote habitat. Here we describe 10 years of results from the National Flying-fox Monitoring Program (NFFMP) for the grey-headed flying-fox, (Pteropus poliocephalus) in Australia. Range-wide quarterly surveys were conducted over a three-day period since November 2012 using standardized methods appropriate to conditions encountered at each roost. For our analysis of the population and its trend, we used a state-space model to account for the ecology of the grey-headed flying-fox and the errors associated with the surveying process. Despite the general perception that the species is in decline, our raw data and the modelled population trend suggest the grey-headed flying-fox population has remained stable during the NFFMP period, with the range also stable. These results indicate that the species' extreme mobility and broad diet bestow it with a high level of resilience to various disturbance events. Long-term, range-wide studies such as this one, are crucial for understanding relatively long-lived and highly nomadic species such as the grey-headed flying-fox. The outcomes of this study highlight the need for such systematic population monitoring of all threatened Pteropus species.
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Affiliation(s)
- Eric Peter Vanderduys
- Environment, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Brisbane, Queensland, Australia
| | - Peter Caley
- Data61, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australian Capital Territory, Australia
| | - Adam McKeown
- Environment, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, South Australia, Australia
| | - John M. Martin
- Wildlife Services, Ecosure, Brisbane, Queensland, Australia
| | - Chris Pavey
- Environment, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Brisbane, Queensland, Australia
| | - David Westcott
- Environment, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Atherton, Queensland, Australia
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Lloyd-Jones LR, Bravington MV, Armstrong KN, Lawrence E, Feutry P, Todd CM, Dorrestein A, Welbergen JA, Martin JM, Rose K, Hall J, Phalen DN, Peters I, Baylis SM, Macgregor NA, Westcott DA. Close-kin mark-recapture informs critically endangered terrestrial mammal status. Sci Rep 2023; 13:12512. [PMID: 37532795 PMCID: PMC10397353 DOI: 10.1038/s41598-023-38639-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 07/12/2023] [Indexed: 08/04/2023] Open
Abstract
Reliable information on population size is fundamental to the management of threatened species. For wild species, mark-recapture methods are a cornerstone of abundance estimation. Here, we show the first application of the close-kin mark-recapture (CKMR) method to a terrestrial species of high conservation value; the Christmas Island flying-fox (CIFF). The CIFF is the island's last remaining native terrestrial mammal and was recently listed as critically endangered. CKMR is a powerful tool for estimating the demographic parameters central to CIFF management and circumvents the complications arising from the species' cryptic nature, mobility, and difficult-to-survey habitat. To this end, we used genetic data from 450 CIFFs captured between 2015 and 2019 to detect kin pairs. We implemented a novel CKMR model that estimates sex-specific abundance, trend, and mortality and accommodates observations from the kin-pair distribution of male reproductive skew and mate persistence. CKMR estimated CIFF total adult female abundance to be approximately 2050 individuals (95% CI (950, 4300)). We showed that on average only 23% of the adult male population contributed to annual reproduction and strong evidence for between-year mate fidelity, an observation not previously quantified for a Pteropus species in the wild. Critically, our population estimates provide the most robust understanding of the status of this critically endangered population, informing immediate and future conservation initiatives.
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Affiliation(s)
- Luke R Lloyd-Jones
- Commonwealth Scientific and Industrial Research Organisation, Data61, Brisbane, QLD, 4072, Australia.
| | - Mark V Bravington
- Commonwealth Scientific and Industrial Research Organisation, Data61, Hobart, TAS, 7000, Australia
| | - Kyle N Armstrong
- Environment Institute, University of Adelaide, North Terrace, Adelaide, South Australia, 5005, Australia
| | - Emma Lawrence
- Commonwealth Scientific and Industrial Research Organisation, Data61, Brisbane, QLD, 4072, Australia
| | - Pierre Feutry
- Commonwealth Scientific and Industrial Research Organisation, Oceans and Atmosphere, Hobart, TAS, 7000, Australia
| | - Christopher M Todd
- The Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Annabel Dorrestein
- The Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Justin A Welbergen
- The Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - John M Martin
- The Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Royal Botanic Gardens and Domain Trust, Sydney, NSW, 2000, Australia
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Bradleys Head Road, Mosman, NSW, 2088, Australia
| | - Karrie Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Bradleys Head Road, Mosman, NSW, 2088, Australia
| | - Jane Hall
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Bradleys Head Road, Mosman, NSW, 2088, Australia
| | - David N Phalen
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, NSW, 2006, Australia
| | - Isabel Peters
- School of Mathematics and Physics, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Shane M Baylis
- Commonwealth Scientific and Industrial Research Organisation, Oceans and Atmosphere, Hobart, TAS, 7000, Australia
| | - Nicholas A Macgregor
- Parks Australia, Canberra, ACT, 2601, Australia
- Durrell Institute of Conservation and Ecology (DICE), School of Anthropology and Conservation, University of Kent, Canterbury, CT2 7NR, Kent, UK
| | - David A Westcott
- Land and Water, Commonwealth Scientific and Industrial Research Organisation, Atherton, QLD, 4883, Australia
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Pulscher LA, Dierenfeld ES, Welbergen JA, Rose KA, Phalen DN. A comparison of nutritional value of native and alien food plants for a critically endangered island flying-fox. PLoS One 2021; 16:e0250857. [PMID: 34010334 PMCID: PMC8133443 DOI: 10.1371/journal.pone.0250857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 04/14/2021] [Indexed: 11/19/2022] Open
Abstract
Habitat loss and alteration are two of the biggest threats facing insular flying-foxes. Altered habitats are often re-vegetated with introduced or domestic plant species on which flying-foxes may forage. However, these alien food plants may not meet the nutritional requirements of flying-foxes. The critically endangered Christmas Island flying-fox (CIFF; Pteropus natalis) is subject to habitat alteration and the introduction of alien food plants, and therefore is a good model species to evaluate the potential impact of alien plant species on insular flying-foxes. In this study, we evaluated nutritional content of native food plants to determine how flying-foxes historically met their nutritional requirements. Furthermore, we compared the nutritional content of native and alien fruits to predict possible impacts of alien plants on insular flying-foxes. Native and alien fruits and flowers, and native foliage (leaves, petals, and petioles) commonly consumed by the CIFF were collected and evaluated for soluble sugars, crude protein, non-fiber carbohydrates, and nine minerals. Evaluation of native food plants suggests that flying-foxes meet energy requirements by consuming fruit and nectar. However, fruit and nectar are low in protein and essential minerals required for demanding life periods; therefore, flying-foxes likely supplement their diets with pollen and foliage. Thus, flying-foxes require a diverse array of plants to meet their nutritional requirements. Compared to native fruits, alien fruits contained significantly higher non-fiber carbohydrates, and this may provide an important energy source, particularly from species that bear fruit year-round. Median mineral concentrations in alien fruit species, however, were deficient compared to native fruits, suggesting major (or even seasonal) shifts in the proportion of alien species in the CIFF diet could lead to nutritional imbalances. This study confirms the need to quantify nutritional parameters in addition to feeding ecology when evaluating habitat quality to inform conservation actions that can be applied both locally and globally.
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Affiliation(s)
- Laura A. Pulscher
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
| | - Ellen S. Dierenfeld
- Ellen S. Dierenfeld, LLC, St. Louis, Missouri, United States of America
- Nottingham Trent University, Southwell, United Kingdom
| | - Justin A. Welbergen
- Hawksbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Karrie A. Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, New South Wales, Australia
| | - David N. Phalen
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
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Todd CM, Westcott DA, Rose K, Martin JM, Welbergen JA. Slow growth and delayed maturation in a Critically Endangered insular flying fox ( Pteropus natalis). J Mammal 2018; 99:1510-1521. [PMID: 30538341 PMCID: PMC6283735 DOI: 10.1093/jmammal/gyy110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/24/2018] [Indexed: 11/14/2022] Open
Abstract
Flying foxes (family Pteropodidae) have distinct life histories given their size, characterized by longevity, low reproductive output, and long gestation. However, they tend to decouple the age at which sexual maturity is reached from the age at which they reach adult dimensions. We examined growth, maturation, and reproduction in the Critically Endangered Christmas Island flying fox (Pteropus natalis) to determine the timing of sex-specific life cycle events and patterns of growth. We estimated that juvenile growth in forearm length and body mass increased at a mean rate of 0.029 ± 0.005 mm/day and 0.33 ± 0.07 g/day for both males and females alike. Using these growth rates, we determined that the birth of pups occurs between December and March, with young becoming volant between June and August. The age at maturation for P. natalis is one of the oldest among all bat species. Juvenile males began to mature 15 months after birth and reached maturity 27 months after birth. Females reached maturity 24 months after birth at a significantly smaller body mass (3.6%) and forearm length (1.4%) than males. Significant sexual dimorphism and bimaturation was observed, with juvenile males being 1.5% and adult males being 1.9% larger on average than females for skeletal dimensions only. Growth and maturation are even slower in P. natalis than in the few other Pteropus species studied to date. The slow growth and delayed maturation of P. natalis imply slower potential population growth rates, further complicating the recovery of this Critically Endangered single-island endemic.
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Affiliation(s)
- Christopher M Todd
- The Hawkesbury institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - David A Westcott
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Land and Water, Maunds St. Atherton, Queensland, Australia
| | - Karrie Rose
- Taronga Conservation Society Australia, Australian Registry Wildlife Health, Mosman, New South Wales, Australia
| | - John M Martin
- Royal Botanic Gardens and Domain Trust, Mrs Macquaries Road, Sydney, New South Wales, Australia
| | - Justin A Welbergen
- The Hawkesbury institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
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