Tigers: Connecting the dots in a fragmented landscape

This is the first of a series on tiger population connectivity in a changing landscape.

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Tigers (Panthera tigris) inhabit thirteen countries across Asia, but they currently occupy only 7% of their historical range. Recent estimates suggest that as few as 3,200 tigers may remain in the wild. Although the accuracy of tiger population estimates is a topic of scientific debate, widespread evidence supports a large-scale decline in tiger numbers over the past several decades, driven primarily by habitat loss and fragmentation, poaching, and a reduction in available prey.

Tiger Range map_copyrightToday most tiger populations are limited to small forested protected areas surrounded by human-dominated landscapes. Tigers may not commonly disperse across large areas (e.g., >20 km wide) of agricultural or urbanized landscapes, but they have been known to travel through broad expanses of degraded forests. One tiger, radio-collared for GPS tracking of its movement, completed a 450 km journey in India through a mix of agricultural lands and forest fragments over a four-month period. Individual tigers have been known to travel more than 690 km between protected areas.

A wide range of management strategies can be used to support tiger conservation. Most recently, efforts have focused on protecting and increasing tiger populations at “source sites” such as protected tiger reserves, landscape-level planning to promote movement of tigers through human-dominated areas outside of protected reserves, and reducing illegal poaching of tigers and their prey. In planning for connectivity of tiger populations, satellite images can be combined with tiger movement data from radio telemetry or genetic studies to identify potentially important tiger dispersal corridors.

As we look for management strategies that work for tiger conservation, one such effort is underway in the country of Bhutan.  In the spring of 2015 it was announced that the nation’s tiger population may be one-third larger than previously thought, with a current estimate of 103 individuals.  Tigers are expected to thrive under a constitutional mandate that ensures that at least 60% of  the country’s land area will remain under forest cover forever.  Ten protected areas (five national parks, four wildlife sanctuaries, and one nature reserve) are linked by a network of nine biodiversity corridors, ensuring a permeable landscape for the survival of tigers and other wide-ranging species.

Next up: Challenges for tiger population connectivity within the Myanmar-Thailand forest complex, a guest blog with Nirmal Ghosh.

Resources

Athreya, V., R. Navya, G.A. Punjabi, J.D.C. Linnell, M. Odden, S. Khetarpal, and K.U. Karanth. 2014. Movement and activity pattern of a collared tigress in a human-dominated landscape in central India. Tropical Conservation Science 7(1): 75-86.

Dinerstein, E., C. Loucks, E. Wikramanayake, J. Ginsburg, E. Sanderson, J. Seidensticker, J. Forrest, G. Bryja, A. Heydlauff, S. Klenzendorf, P. Leimgruber, J. Mills, T.G. O’Brien, M. Shrestha, R. Simons, and M. Songer. 2007. The fate of wild tigers. Bioscience 57(6): 508-514.

Kenney J., F.W. Allendorf, C. McDougal, and J.L.D. Smith. 2014. How much gene flow is needed to avoid inbreeding depression in wild tiger populations? Proceedings of the Royal Society B 281: 20133337.

Rathore C.S., Y. Dubey, A. Shrivastava, P. Pathak, and V. Patil. 2012. Opportunities of habitat connectivity for tiger (Panthera tigris) between Kanha and Pench National Parks in Madhya Pradesh, India. PLoS ONE 7(7): e39996.

Smith, J.L.D. 1993. The role of dispersal in structuring the Chitwan tiger population. Behaviour 124: 165-195.

Walston, J., J.G. Robinson, E.L. Bennett, U. Breitenmoser, G.A.B. Fonseca, J. Goodrich, M. Gumal, L. Hunter, A. Johnson, K.U. Karanth, N. Leader-Williams, K. MacKinnon, D. Miquelle, A. Pattanavibool, C. Poole, A. Rabinowitz, J.L.D. Smith, E.J. Stokes, S.N. Stuart, C. Vongkhamheng, and H. Wibisono. 2010. Bringing the tiger back from the brink—the six percent solution. PLoS Biol 8(9): e1000485.

Wikramanayake, E., M. McNight, E. Dinerstein, A. Joshi, B. Gurung, and D. Smith. 2004. Designing a conservation landscape for tigers in human-dominated environments. Conservation Biology (18): 839-844.

Yumnam, B., Y.V. Jhala, W. Qureshi, J.E. Maldonado, R. Gopal, S. Saini, Y. Srinivas, and R.C. Fleischer. 2014. Prioritizing tiger conservation through landscape genetics and habitat linkages. PLoS ONE 9(11): e111207.

Bhutan Foundation Web Site: www.bhutanfound.org

See related posts:

Mapping tiger attack hotspots to reduce conflict (Miller et al. 2015 Ecol. and Evol.)

Tigers in Malaysia: using science to influence policy (Rayan and Linkie 2015 Biol. Cons.)

Tiger populations are protected, but are they connected? (Joshi et al. 2013 PLos ONE)

Corridor success in connecting tiger metapopulation (Sharma et al. 2013 Proc. Roy. Soc.)

2016-10-14T10:10:31-04:00 September 16th, 2015|

About the Author:

Lisa Mills and Ellen Cheng
Lisa Mills (R), M.Ed., is an Outreach Specialist with the North Carolina State University (NCSU) College of Natural Resources. She develops community-based conservation and education programs to address environmental change and human well-being issues. Currently she is working with partners in Asia, Africa and the U.S. with programs that address wildlife, habitat and human-wildlife conflict issues. She is the coordinator for NCSU for Elephants on the Line, a community-based conservation and education program with Bhutan, India and U.S. partners and The Maasai Twiga Trackers Giraffe Conservation and Education Program in Kenya. Ellen Cheng (L), Ph.D., is a wildlife biologist who works with governments and communities in Asia to increase local capacity for conserving and managing wildlife. For the past three years she has worked in Bhutan with the Ugyen Wangchuck Institute for Conservation and Environment. She is also a partner with NCSU's Elephants on the Line, a community-based conservation and education program for the Indo-Bhutan border region.