Research article: Mondol, S., Kumar, N. S., Gopalaswamy, A. M., Sunagar, K., Karanth, K. U., & Ramakrishnan, U. (2015). Identifying species, sex and individual tigers and leopards in the Malenad-Mysore Tiger Landscape, Western Ghats, India. Conservation Genetics Resources, 7(2), 353–361.

Blog Author: Dolsy David

Highlights:

  • Malenad Mysore Tiger Landscape forms the south-central part of the Western Ghats, which includes 14 protected areas in the state of Karnataka. Extending over 22,400 km2, it consists of moist-evergreen, moist-deciduous and dry-deciduous forest types, therefore forming a prime habitat for large carnivores.
  • It is important to understand the distribution, abundance and demographic ratios of endangered carnivore species at a landscape level to plan for its proactive management. However, many field-based methods fail to provide accurate identification of species,  its gender and even identify individual animals. 
  • The researchers developed a new non-invasive molecular approach using the faecal DNA of tiger and leopard which facilitates rapid screening of a large number of samples with fewer steps in sample processing. 
  • Utilizing this novel approach, from the field-collected samples, the researchers were successful in identifying and assigning 88% of the samples to the species or related species level and were successful in determining the sex of 57% of the samples. Overall, the individual identification of 60% and 78% of the selected tiger and leopard samples were possible. 
  • This study demonstrates the value of understanding the distribution of large carnivores at a landscape level and also provides information on the same. 

 

In these challenging times for wildlife, it is imperative to understand the distribution, abundance and demographic ratios of endangered carnivore species at a landscape level to plan for proactive management techniques. However,  it has always been difficult for biologists to acquire such knowledge for wide-ranging large carnivores because of their rare and elusive characteristics. Many direct and indirect non-invasive methods have been used to collect data on the distribution of such species,  i.e., sign-track surveys, faecal encounters, remote camera trapping etc.

Sign-track surveys or faecal examination based on size, shape, scent and dietary contents often fail to ascertain species and individual identification, as well as gender, in similar body-sized carnivore species which occur together in overlapping home ranges. The use of cameras is logistically challenging in such remote landscapes and it cannot distinguish between species in which individuals and their genders are not particularly  different,  such as jungle cats. Therefore, DNA-based methods have become a better option for accurate species, gender, and individual identification. However, such long-term studies over the large landscapes of these rare, threatened and elusive species have logistical and financial limitations as these methods require skilled researchers, encompass rough terrains for sample collection, and a great deal of time and money to test the samples in a well-equipped lab.

In this paper, the researchers describe various genetic tools to identify species, sex and individuals from degraded biological samples of tigers and leopards. Further, it was tested on faecal samples collected under a pilot study to monitor tiger/leopard distribution and demography conducted in Malenad Mysore Tiger Landscape (MMTL). Extending over 22,400 km2, MMTL forms the south-central part of the Western Ghats. It consists of moist-evergreen, moist-deciduous and dry-deciduous forest types, which include 14 protected areas in the state of Karnataka, therefore forming a prime habitat for large carnivores. MMTL was divided into grids of 188 km sq and each grid, containing more than 10% of forest cover, was sampled between the months of November 2006 –June 2007. The faecal samples were collected along the forest roads, trails, and river banks used by the species inside the forest. The samples were stored at room temperature in alcohol till their processing.

Molecular markers for species identification were designed in the lab. Faecal DNA was extracted from all the faecal samples. Markers were checked with a set of reference samples, including those for common co-occuring carnivores and primary prey species, for species specificity. Further, all field-collected samples were analyzed for species and sex identification. All tiger samples, and selected leopard samples, were individually identified and molecular testing was conducted to develop and optimize a range of new, non-invasive molecular techniques for species, gender, and individual identification of tiger and leopard.

Of the field-collected samples, 88% were successfully identified and assigned to the species or related species level.  Of these, 73.4% of samples were assigned to leopards and 12.5% to tigers. A success rate of 57% was produced for determining the sex of all the samples collected from the field. Of the total samples, gender was determined for 58.5% leopards and 46% tigers. Overall, 60% and 78% of the selected tiger and leopard samples, respectively, were individually identified. The methods described in the paper facilitate rapid screening of a large number of samples using fewer steps in sample processing, reduced identification error of species or sex, and are more cost-effective than other approaches. The authors were successful in designing molecular markers which are also applicable to other smaller feline species.

Lastly, this study also gives information about the distribution of these carnivores in the landscape, wherein 40% of the leopard samples were found outside protected areas, compared to 28% of tiger samples. Results also showed that about 50% of the samples outside protected areas were females, implicating both male- and female-driven dispersal in this landscape. Given the increasing rate of global population decline of these large carnivores, the researchers believe that such novel interdisciplinary approaches are crucial to assess the distribution and demographic status of two of the largest endangered feline species throughout their habitat, for their survival. This process is similar to creating an ID card for each individual to keep track of their movement and demographic information for better management.

 

You can access the article here.

Keywords: Species identification, Molecular sexing, tiger, leopard, Carnivore conservation, gender identification, individual identification, Malenad Mysore Tiger Landscape