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Alymann AA, Alymann IA, Ong SQ, Rusli MU, Ahmad AH, Salim H. Morphometric dataset of Varanus salvator for non-invasive sex identification using machine learning. Sci Data 2024; 11:337. [PMID: 38580692 PMCID: PMC10997747 DOI: 10.1038/s41597-024-03172-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/21/2024] [Indexed: 04/07/2024] Open
Abstract
Reliable sex identification in Varanus salvator traditionally relied on invasive methods like genetic analysis or dissection, as less invasive techniques such as hemipenes inversion are unreliable. Given the ecological importance of this species and skewed sex ratios in disturbed habitats, a dataset that allows ecologists or zoologists to study the sex determination of the lizard is crucial. We present a new dataset containing morphometric measurements of V. salvator individuals from the skin trade, with sex confirmed by dissection post- measurement. The dataset consists of a mixture of primary and secondary data such as weight, skull size, tail length, condition etc. and can be used in modelling studies for ecological and conservation research to monitor the sex ratio of this species. Validity was demonstrated by training and testing six machine learning models. This dataset has the potential to streamline sex determination, offering a non-invasive alternative to complement existing methods in V. salvator research, mitigating the need for invasive procedures.
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Affiliation(s)
- Ariff Azlan Alymann
- Barn Owl and Rodent Research Group, School of Biological Sciences, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Imann Azlan Alymann
- Barn Owl and Rodent Research Group, School of Biological Sciences, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Song-Quan Ong
- Barn Owl and Rodent Research Group, School of Biological Sciences, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
- Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia
| | - Mohd Uzair Rusli
- Sea Turtle Research Unit (SEATRU), Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia
| | - Abu Hassan Ahmad
- Barn Owl and Rodent Research Group, School of Biological Sciences, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Hasber Salim
- Barn Owl and Rodent Research Group, School of Biological Sciences, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia.
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Macdonald KJ, Driscoll DA, Macdonald KJ, Hradsky B, Doherty TS. Meta-analysis reveals impacts of disturbance on reptile and amphibian body condition. GLOBAL CHANGE BIOLOGY 2023; 29:4949-4965. [PMID: 37401520 DOI: 10.1111/gcb.16852] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/06/2023] [Accepted: 06/14/2023] [Indexed: 07/05/2023]
Abstract
Ecosystem disturbance is increasing in extent, severity and frequency across the globe. To date, research has largely focussed on the impacts of disturbance on animal population size, extinction risk and species richness. However, individual responses, such as changes in body condition, can act as more sensitive metrics and may provide early warning signs of reduced fitness and population declines. We conducted the first global systematic review and meta-analysis investigating the impacts of ecosystem disturbance on reptile and amphibian body condition. We collated 384 effect sizes representing 137 species from 133 studies. We tested how disturbance type, species traits, biome and taxon moderate the impacts of disturbance on body condition. We found an overall negative effect of disturbance on herpetofauna body condition (Hedges' g = -0.37, 95% CI: -0.57, -0.18). Disturbance type was an influential predictor of body condition response and all disturbance types had a negative mean effect. Drought, invasive species and agriculture had the largest effects. The impact of disturbance varied in strength and direction across biomes, with the largest negative effects found within Mediterranean and temperate biomes. In contrast, taxon, body size, habitat specialisation and conservation status were not influential predictors of disturbance effects. Our findings reveal the widespread effects of disturbance on herpetofauna body condition and highlight the potential role of individual-level response metrics in enhancing wildlife monitoring. The use of individual response metrics alongside population and community metrics would deepen our understanding of disturbance impacts by revealing both early impacts and chronic effects within affected populations. This could enable early and more informed conservation management.
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Affiliation(s)
- Kristina J Macdonald
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - Don A Driscoll
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - Kimberley J Macdonald
- Biodiversity Protection and Information Branch, Biodiversity Division, Department of Energy, Environment and Climate Action, East Melbourne, Victoria, Australia
| | - Bronwyn Hradsky
- School of Ecosystem and Forest Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Tim S Doherty
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
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Twining JP, McFarlane C, O'Meara D, O'Reilly C, Reyne M, Montgomery WI, Helyar S, Tosh DG, Augustine BC. A comparison of density estimation methods for monitoring marked and unmarked animal populations. Ecosphere 2022. [DOI: 10.1002/ecs2.4165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Joshua P. Twining
- Department of Natural Resources Cornell University Ithaca New York USA
| | - Claire McFarlane
- School of Biological Sciences Queen's University of Belfast Belfast UK
| | - Denise O'Meara
- Molecular Ecology Research Group, Eco‐innovation Research Centre School of Science and Computing, South East Technological University Waterford UK
| | - Catherine O'Reilly
- Molecular Ecology Research Group, Eco‐innovation Research Centre School of Science and Computing, South East Technological University Waterford UK
| | - Marina Reyne
- School of Biological Sciences Queen's University of Belfast Belfast UK
| | - W. Ian Montgomery
- School of Biological Sciences Queen's University of Belfast Belfast UK
| | - Sarah Helyar
- School of Biological Sciences Queen's University of Belfast Belfast UK
| | - David G. Tosh
- Raithlin LIFE Project The Royal Society for Protection of Birds, Belvoir Park Forest Belfast UK
| | - Ben C. Augustine
- Department of Natural Resources Cornell University Ithaca New York USA
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Guerrero‐Sanchez S, Majewski K, Orozco‐terWengel P, Saimin S, Goossens B. The effect of oil palm-dominated landscapes on the home range and distribution of a generalist species, the Asian water monitor. Ecol Evol 2022; 12:e8531. [PMID: 35127037 PMCID: PMC8794710 DOI: 10.1002/ece3.8531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/27/2021] [Accepted: 12/17/2021] [Indexed: 11/05/2022] Open
Abstract
The Asian water monitor lizard, Varanus salvator, is one of the largest predators in Southeast Asia which persists in human-dominated landscapes and, as such, is a suitable model to understand the behavioral plasticity of generalists in anthropogenic landscapes. We used Local Convex Hull with adaptive algorithm to estimate the home range size of 14 GPS-tagged individuals, followed by a MAXENT approach and community prey composition to understand the habitat preferences within the landscape. We estimated larger home ranges in forest than in oil palm plantations, as well as a larger diversity and abundance of mammals. Core home ranges were always linked to water bodies. However, the use of underproductive oil palm, freshwater swamp forest, and degraded forest by monitor lizards were higher than other kind of vegetation. This suitable habitat is proportionally larger in forest (73.7%) than in oil palm plantations (39.6%). Generalized estimation equation models showed that, while full home range size was negatively associated with the abundance of mammals, core areas depicted a positive association with mammal abundance, as well as with the proportion of suitable habitat within the home range. Besides having smaller home ranges in oil palm plantations, our findings suggest that limited suitable habitat availability forces the Asian water monitor lizard's population to establish only one or very few core areas. Contrastingly, under the protection of forest, they have more core areas, widely dispersed within larger home ranges. We conclude that regardless the plasticity of the species, human-dominated landscapes are altering natural patterns of home range establishment in the monitor lizard's population, creating a potential ecological trap where conditions may not remain favorable for them in the long run. A deeper understanding of the ecological implications on the species and the prey community is advisable.
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Affiliation(s)
- Sergio Guerrero‐Sanchez
- Organisms and Environment DivisionSchool of BiosciencesCardiff UniversityCardiffUK
- Danau Girang Field Centre, c/o Sabah Wildlife DepartmentKota KinabaluMalaysia
- Present address:
Institute of Borneo StudiesUniversity College Sabah FoundationKota KinabaluMalaysia
| | - Katherine Majewski
- Organisms and Environment DivisionSchool of BiosciencesCardiff UniversityCardiffUK
- Danau Girang Field Centre, c/o Sabah Wildlife DepartmentKota KinabaluMalaysia
| | | | | | - Benoit Goossens
- Organisms and Environment DivisionSchool of BiosciencesCardiff UniversityCardiffUK
- Danau Girang Field Centre, c/o Sabah Wildlife DepartmentKota KinabaluMalaysia
- Sabah Wildlife DepartmentKota KinabaluMalaysia
- Sustainable Places Research InstituteCardiff UniversityCardiffUK
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Guerrero-Sanchez S, Goossens B, Saimin S, Orozco-terWengel P. The critical role of natural forest as refugium for generalist species in oil palm-dominated landscapes. PLoS One 2021; 16:e0257814. [PMID: 34614000 PMCID: PMC8494349 DOI: 10.1371/journal.pone.0257814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 09/11/2021] [Indexed: 11/19/2022] Open
Abstract
In Borneo, oil palm plantations have replaced much of natural resources, where generalist species tend to be the principal beneficiaries, due to the abundant food provided by oil palm plantations. Here, we analyse the distribution of the Asian water monitor lizard (Varanus salvator) population within an oil palm-dominated landscape in the Kinabatangan floodplain, Malaysian Borneo. By using mark-recapture methods we estimated its population size, survival, and growth in forest and plantation habitats. We compared body measurements (i.e. body weight and body length) of individuals living in forest and oil palm habitats as proxy for the population's health status, and used general least squares estimation models to evaluate its response to highly fragmented landscapes in the absence of intensive hunting pressures. Contrary to previous studies, the abundance of lizards was higher in the forest than in oil palm plantations. Recruitment rates were also higher in the forest, suggesting that these areas may function as a source of new individuals into the landscape. While there were no morphometric differences among plantation sites, we found significant differences among forested areas, where larger lizards were found inhabiting forest adjacent to oil palm plantations. Although abundant in food resources, the limited availability of refugia in oil palm plantations may intensify intra-specific encounters and competition, altering the body size distribution in plantation populations, contrary to what happens in the forest. We conclude that large patches of forest, around and within oil palm plantations, are essential for the dynamics of the monitor lizard population in the Kinabatangan floodplain, as well as a potential source of individuals to the landscape. We recommend assessing this effect in other generalist species, as well as the impact on the prey communities, especially to reinforce the establishment of buffer zones and corridors as a conservation strategy within plantations.
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Affiliation(s)
- Sergio Guerrero-Sanchez
- Organisms and Environment Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
- Danau Girang Field Centre, c/o Sabah Wildlife Department, Kota Kinabalu, Sabah, Malaysia
- * E-mail: (SGS); (BG)
| | - Benoit Goossens
- Organisms and Environment Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
- Danau Girang Field Centre, c/o Sabah Wildlife Department, Kota Kinabalu, Sabah, Malaysia
- Sustainable Places Research Institute, Cardiff University, Cardiff, United Kingdom
- Sabah Wildlife Department, Kota Kinabalu, Sabah, Malaysia
- * E-mail: (SGS); (BG)
| | | | - Pablo Orozco-terWengel
- Organisms and Environment Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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Evans MN, Guerrero-Sanchez S, Kille P, Müller CT, Bakar MSA, Goossens B. Physiological implications of life at the forest interface of oil palm agriculture: blood profiles of wild Malay civets ( Viverra tangalunga). CONSERVATION PHYSIOLOGY 2020; 8:coaa127. [PMID: 33408869 PMCID: PMC7772617 DOI: 10.1093/conphys/coaa127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/23/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
Agricultural development is a major threat to global biodiversity, and effective conservation actions are crucial. Physiological repercussions of life alongside human-modified landscapes can undermine adaptable species' health and population viability; however, baseline data are lacking for many wildlife species. We assessed the physiological status of a generalist carnivore, the Malay civet (Viverra tangalunga), persisting within an extensively human-modified system in Sabah, Malaysian Borneo. We characterized hematology and serum biochemistry panels from civets sampled across a mosaic landscape comprising tropical forest fragments and oil palm plantations. Intra-population variation in certain blood parameters were explained by expected biological drivers such as sex, age category and sampling season. Furthermore, we determined several erythrocyte measures, immune cell counts and dietary biochemistry markers significantly varied with proximity to oil palm plantation boundaries. These findings were supported by a case study, whereby blood profiles of GPS collared male civets were contrasted based on their exclusive use of forests or use of oil palm plantations. These data provide robust and valuable first insights into this species' physiological status and suggest agricultural landscapes are impacting the persisting population.
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Affiliation(s)
- Meaghan N Evans
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
- Danau Girang Field Centre, Kota Kinabalu 88100, Malaysia
| | - Sergio Guerrero-Sanchez
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
- Danau Girang Field Centre, Kota Kinabalu 88100, Malaysia
| | - Peter Kille
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | | | | | - Benoit Goossens
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
- Danau Girang Field Centre, Kota Kinabalu 88100, Malaysia
- Sustainable Places Research Institute, Cardiff University, Cardiff CF10 3BA, UK
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Young KI, Medwid JT, Azar SR, Huff RM, Drumm H, Coffey LL, Pitts RJ, Buenemann M, Vasilakis N, Perera D, Hanley KA. Identification of Mosquito Bloodmeals Collected in Diverse Habitats in Malaysian Borneo Using COI Barcoding. Trop Med Infect Dis 2020; 5:tropicalmed5020051. [PMID: 32244739 PMCID: PMC7344668 DOI: 10.3390/tropicalmed5020051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 12/21/2022] Open
Abstract
Land cover and land use change (LCLUC) acts as a catalyst for spillover of arthropod-borne pathogens into novel hosts by shifting host and vector diversity, abundance, and distribution, ultimately reshaping host–vector interactions. Identification of bloodmeals from wild-caught mosquitoes provides insight into host utilization of particular species in particular land cover types, and hence their potential role in pathogen maintenance and spillover. Here, we collected 134 blood-engorged mosquitoes comprising 10 taxa across 9 land cover types in Sarawak, Malaysian Borneo, a region experiencing intense LCLUC and concomitant spillover of arthropod-borne pathogens. Host sources of blood were successfully identified for 116 (87%) mosquitoes using cytochrome oxidase subunit I (COI) barcoding. A diverse range of hosts were identified, including reptiles, amphibians, birds, and mammals. Sixteen engorged Aedes albopictus, a major vector of dengue virus, were collected from seven land cover types and found to feed exclusively on humans (73%) and boar (27%). Culex tritaeniohynchus (n = 2), Cx. gelidus (n = 3), and Cx. quiquefasciatus (n = 3), vectors of Japanese encephalitis virus, fed on humans and pigs in the rural built-up land cover, creating potential transmission networks between these species. Our data support the use of COI barcoding to characterize mosquito–host networks in a biodiversity hotspot.
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Affiliation(s)
- Katherine I. Young
- Department of Biology, New Mexico State University, Las Cruces NM 88003, USA; (J.T.M.); (K.A.H.)
- Correspondence:
| | - Joseph T. Medwid
- Department of Biology, New Mexico State University, Las Cruces NM 88003, USA; (J.T.M.); (K.A.H.)
| | - Sasha R. Azar
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.R.A.); (N.V.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Robert M. Huff
- Department of Biology, Baylor University, Waco, TX 76706, USA; (R.M.H.); (R.J.P.)
| | - Hannah Drumm
- School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA; (H.D.); (L.L.C.)
| | - Lark L. Coffey
- School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA; (H.D.); (L.L.C.)
- Department of Pathology, Microbiology & Immunology, University of California Davis, Davis, CA 95616, USA
| | - R. Jason Pitts
- Department of Biology, Baylor University, Waco, TX 76706, USA; (R.M.H.); (R.J.P.)
| | - Michaela Buenemann
- Department of Geography, New Mexico State University, Las Cruces, NM 88003, USA;
| | - Nikos Vasilakis
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.R.A.); (N.V.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555, USA
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - David Perera
- Institute of Health and Communiti Medicine, Universiti of Malaysia Sarawak, Sarawak 94300, Malaysia;
| | - Kathryn A. Hanley
- Department of Biology, New Mexico State University, Las Cruces NM 88003, USA; (J.T.M.); (K.A.H.)
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Twining JP, Montgomery I, Fitzpatrick V, Marks N, Scantlebury DM, Tosh DG. Seasonal, geographical, and habitat effects on the diet of a recovering predator population: the European pine marten (Martes martes) in Ireland. EUR J WILDLIFE RES 2019. [DOI: 10.1007/s10344-019-1289-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Khadiejah S, Razak N, Ward-Fear G, Shine R, Natusch DJD. Asian water monitors (Varanus salvator) remain common in Peninsular Malaysia, despite intense harvesting. WILDLIFE RESEARCH 2019. [DOI: 10.1071/wr18166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Each year, between 50000 and 120000 Asian water monitors (Varanus salvator, to >2 m total length) are harvested from the wild in Peninsular Malaysia for their skins. Under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), international trade is allowable only if it is sustainable.
Aims
To assess the sustainability of Malaysia’s harvest of water monitors by quantifying the abundance and demography of V. salvator in the wild, and to develop cost-effective methods for estimating the parameters needed to evaluate sustainability.
Methods
We conducted trapping surveys to determine the abundance, population demography and density of V. salvator in four habitat types in five states in Peninsular Malaysia in 2010, 2011, 2012 and 2018.
Key results
Of 1025 lizards captured, only 63% (mostly females) were within the preferred body-size range exploited for commercial trade. Densities were high (37–372 lizards km–2 based on estimated population sizes; 1–35 lizards km–2 based on number of animals captured). Anthropogenic habitats (e.g. oil palm plantations) contained denser populations of monitors than did natural habitats where no hunting occurs, but mean body sizes were smaller.
Conclusions
Despite intensive harvesting for many decades, V. salvator remains abundant and widespread. Harvesting alters the demographic structure of lizard populations, but harvests of V. salvator in Malaysia are likely to be sustainable because a significant proportion of the population is not exploited.
Implications
Ongoing monitoring is required to continually reassess harvest sustainability. For this purpose, relatively simple population approaches, such as line-trapping transects to elucidate relative abundances, can provide important data on the makeup of hunted populations of water monitors more cost-effectively than can mark–recapture studies for assessments of sustainable use of these economically important lizards.
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