Skip to main content Accessibility help
×
Home

Impacts of anthropogenic pressures on the contemporary biogeography of threatened crocodilians in Indonesia

  • Kyle J. Shaney (a1), Amir Hamidy (a2), Matthew Walsh (a1), Evy Arida (a2), Aisyah Arimbi (a3) and Eric N. Smith (a1)...

Abstract

The Greater Sunda region of South-east Asia supports a rich diversity of economically and ecologically important species. However, human pressures are reshaping contemporary biogeography across the region. Megafaunal distributional patterns have been particularly affected because of deforestation, poaching and human–wildlife conflict. Crocodilians are at the centre of these conflicts in Indonesia and yet remain poorly studied across much of the archipelago. We conducted population surveys of salt-water crocodiles Crocodylus porosus and false gharials Tomistoma schlegelii in Sumatra, and examined whether crocodile abundance and distribution are correlated with variations in human disturbance, fishing pressure, and habitat type. We then used these data to model remaining suitable habitat for T. schlegelii across South-east Asia. We found that abundance of T. schlegelii and C. porosus was correlated with distance from human settlements, and fish-trapping pressure. We recorded the presence of T. schlegelii in a river system in which it was previously unknown, thus expanding the known range of the species. We also found that the predicted remaining suitable habitat for T. schlegelii in Indonesia is largely limited to areas of low human activity. From these empirical and modelling approaches we propose several key conservation priorities: (1) eliminate the use of fish traps in remaining patches of T. schlegelii habitat, (2) prioritize crocodile population surveys in remaining suitable habitat, particularly in remote areas, (3) consider T. schlegelii to be potentially Endangered locally in Sumatra, and (4) expand existing reserves around the Lower Kampar River and Berbak National Park/Sembilang National Park areas of Sumatra.

Copyright

Corresponding author

(Corresponding author) E-mail kjshaney@uta.edu

References

Hide All
Auliya, M., Shwedick, B., Sommerlad, R., Brend, S. & Samedi, (2006) A short-term assessment of the conservation status of Tomistoma schlegelii (Crocodylia: Crocodylidae) in Tanjung Puting National Park (Central Kalimantan, Indonesia). A cooperative survey by the Orangutan Foundation (UK) and the Tomistoma Task Force of the IUCN/SSC Crocodile Specialist Group. Https://www.iucncsg.org/365_docs/attachments/protarea/Tomi-9bc5a8d8.pdf [accessed 4 July 2017].
Bayliss, P. (1987) Survey methods and monitoring within crocodile management programmes. In Wildlife Management: Crocodiles and Alligators (eds Webb, G.J.W., Manolis, S.C. & Whitehead, P.J.), pp. 16163. Surrey Beatty & Sons Pty Ltd, Chipping Norton, Australia.
Bezuijen, M.R., Cannucciar, P., Manolis, S.C., Samedi, , Kadarisman, R. & Simpson, B.K. (1995) Project Tomistoma. Field Expedition to the Lalan River and its Tributaries, South Sumatra, Indonesia, August–October 1995: Assessment of the Distribution, Abundance, Status and Nesting Biology of the False Gharial (Tomistoma schlegelii). Wildlife Management International Pty Limited, Darwin, Australia.
Bezuijen, M.R., Hartoyo, P., Elliott, M. & Baker, B.A. (1997) Project Tomistoma. Second Report on the Ecology of the False Gharial (Tomistoma schlegelii) in Sumatera. Wildlife Management International Pty Limited, Darwin, Australia.
Bezuijen, M.R., Shwedick, B., Simpson, B.K., Staniewicz, A. & Stuebing, R. (2014) Tomistoma schlegelii. In The IUCN Red List of Threatened Species 2014: e.T21981A2780499. Http://dx.doi.org/10.2305/IUCN.UK.2014-1.RLTS.T21981A2780499.en [accessed 4 July 2017].
Bezuijen, M.R., Webb, G.J.W., Hartoyo, P. & Samedi, (2001) Peat swamp forest and the false gharial Tomistoma schlegelii (Crocodilia, Reptilia) in the Merang River, eastern Sumatra, Indonesia. Oryx., 35, 301307.
Bezuijen, M.R., Wibowo, P. & Wirawijaya, H. (2002) Proceedings of the 2002 False Gharial Workshop: Assessment of the Management and Conservation of the Merang River as Habitat for the False Gharial (Tomistoma schlegelii). Wildlife Management International Pty Limited, Darwin, Australia, and Wetlands International–Indonesia Program, Palembang, Indonesia.
Bonke, R., Auliya, M., Brend, S., Sommerlad, R. & Böhme, W. (2008) Population Ecology of Tomistoma schlegelii (Müller, 1838) in the Tanjung Puting National Park (Central Kalimantan, Indonesia). Progress report for IUCN/SSC–Tomistoma Task Force.
Brien, M., Shwedick, B., McCaskill, L., Ramono, W. & Webb, G. (2015) Crocodile Conservation, Management and Farming in Indonesia: A Preliminary Review with Recommendations. Summary report of the IUCN-SSC Crocodile Specialist Group review mission to Indonesia (23 August–17 September 2014).
Brodie, J.F., Giordano, A.J., Zipkin, E.F., Bernard, H., Mohd-Azlan, J. & Ambu, L. (2015) Correlation and persistence of hunting and logging impacts on tropical rainforest mammals. Conservation Biology, 29, 110121.
Brooks, T.M., Pimm, S.L. & Collar, N.J. (1997) Deforestation predicts the number of threatened birds in insular Southeast Asia. Conservation Biology, 11, 382394.
CITES (2017) The CITES Appendices. Http://www.cites.org/eng/app/index.shtml [accessed 4 July 2017].
CrocBITE (2016) Worldwide Crocodilian Attack Database. Http://www.crocodile-attack.info/ [accessed 25 December 2015].
Crocodile Specialist Group (1996) Crocodylus porosus. In The IUCN Red List of Threatened Species 1996: e.T5668A11503588. Http://dx.doi.org/10.2305/IUCN.UK.1996.RLTS.T5668A11503588.en [accessed 4 July 2017].
DIVA-GIS (2015) http://www.diva-gis.org [accessed 6 May 2016].
Elith, J., Phillips, S.J., Hastie, T., Dudík, M., Chee, Y.E. & Yates, C.J. (2011) A statistical explanation of MaxEnt for ecologists. Diversity and Distributions, 17, 4357.
Margono, B.A., Turubanova, S., Zhuravleva, I., Potapov, P., Tyukavina, A., Baccini, A. et al. (2012) Mapping and monitoring deforestation and forest degradation in Sumatra (Indonesia) using Landsat time series data sets from 1990 to 2010. Environmental Research Letters, 7, http://dx.doi.org/10.1088/1748-9326/7/3/034010.
Miettinen, J., Stibig, H.J. & Achard, F. (2014) Remote sensing of forest degradation in Southeast Asia—aiming for a regional view through 5–30 m satellite data. Global Ecology and Conservation, 2, 2436.
Phillips, S.J., Dudík, M. & Schapire, R.E. (2016) Maxent software for modeling species niches and distributions. Http://biodiversityinformatics.amnh.org/open_source/maxent/ [accessed 10 March 2017].
Rödder, D., Engler, J.O., Bonke, R., Weinsheimer, F. & Pertel, W. (2010) Fading of the last giants: an assessment of habitat availability of the Sunda gharial Tomistoma schlegelii and coverage with protected areas. Aquatic Conservation: Marine and Freshwater Ecosystems, 20, 678684.
Shaney, K.J., Hamidy, A. & Smith, E.N. (2016) Status of the False Gharial in Sumatra. IUCN Crocodile Specialist Group Report. IUCN, Gland, Switzerland.
Shaney, K.J., Trilaksono, W., Hamidy, A. & Smith, E.N. (2015) Preliminary Assessment of False Gharial (Tomistoma schlegelii) Populations in Sumatra. IUCN Crocodile Specialist Group Report (Tomistoma Task Force). Http://www.iucncsg.org/365_docs/attachments/protarea/02955f7103662bf1710d9281764de798.pdf [accessed 4 July 2017].
Simpson, B.K. (2014) Status Assessment of Tomistoma in Peninsular Malaysia: Peat Swamp Forests of Selangor & Pahang. IUCN Crocodile Specialist Group, Tomistoma Task Force.
Sodhi, N.S., Koh, L.P., Brook, B.W. & Ng, P.K.L. (2004) Southeast Asian biodiversity: an impending disaster. Trends in Ecology & Evolution, 19, 654660.
Stoner, D.C., Wolfe, M.L., Rieth, W.R., Bunnell, K.D., Durham, S.L. & Stoner, L.L. (2013) De facto refugia, ecological traps and the biogeography of anthropogenic cougar mortality in Utah. Diversity and Distributions, 19, 11141124.
Stuebing, R.B., Bezuijen, M.R., Auliya, M. & Voris, H.K. (2006) The current and historic distribution of Tomistoma schlegelii (the false gharial) (Müller, 1838) (Crocodylia, Reptilia). The Raffles Bulletin of Zoology, 54, 181197.
Stuebing, R., Sommerlad, R. & Staniewicz, A. (2015) Conservation of the Sunda gharial Tomistoma schlegelii in Lake Mesangat Indonesia. International Zoo Yearbook, 49, 137149.
Webb, G.J.W., Manolis, S.C. & Brien, M.L. (2010) Saltwater Crocodile Crocodylus porosus. IUCN Crocodile Specialist Group report. IUCN, Gland, Switzerland.
WorldClim (2016) WorldClim – Global Climate Data. Http://worldclim.com/ [accessed 20 December 2016].

Keywords

Impacts of anthropogenic pressures on the contemporary biogeography of threatened crocodilians in Indonesia

  • Kyle J. Shaney (a1), Amir Hamidy (a2), Matthew Walsh (a1), Evy Arida (a2), Aisyah Arimbi (a3) and Eric N. Smith (a1)...

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed