Leeches – The future of conservation ?

Photo Courtesy of Thejaswi

 A recent breakthrough in the mission to assess the presence of highly elusive endangered species has come to the forefront of science in the last month. A novel and innovative method to use leeches as a key to understanding what species are within a particular region is now being implemented.

Leeches are highly abundant throughout tropical forests and are extremely hard to avoid. In a normal context this is hugely frustrating for anyone trekking through forests, however these blood suckers may be more valuable and imperative than it would initially seem. Conservationists and scientific researchers are now extremely interested in the prospect of environmental DNA.  Environmental DNA analysis relies on short DNA sequences which are unique to one species alone. This ‘meta bar coding’ allows for specific species to be identified through the recovery of small portions of DNA within the environment. These codes can often be compared to a DNA library in order to detect the organism from which the DNA was derived.

It is here where leeches become the key factor, due to their blood sucking lifestyle.  Leeches are able to store blood from their prey for months, and therefore analysis of this blood meal can provide a great deal of information about the presence of animals within the forest. The method unfortunately cannot produce information about the abundances of species, but for some critically endangered organisms, just the knowledge of their presence is enough. This method therefore provides an extremely effective and cheap monitoring technique. DNA sequencing is reducing in cost and thus analysis will become even more cost effective in the future, and the collection of leeches is relatively unchallenging, so as a whole the technique is extremely effective.

This technique is providing hope for many species such as the saola (Psuedoryx nghetinhensis), presumed to inhabit the forests of Vietnam. This elusive creature has been seen extremely infrequently in the last few decades, and had previously gone undetected until 2010 when a reported capture was documented. Conservationists are now hoping to seek out leeches from the region in order to confirm the presence of the saol through environmental DNA. Analysis of blood meals will hopefully provide vital information on the local biodiversity, and potentially document other rare species.

Other research teams have also been investigating environmental DNA from water samples in Canada. DNA sequencing from river samples identified invertebrate species equivalent to those established in observation surveys, thus reaffirming the efficacy of such techniques to survey species diversity.

The future of DNA sequencing is highly promising and the cost effective use of leeches is highly productive for conservation. The ability of leeches to reach deeper into the forest is an exceptionally valuable tool. Observational studies are often impractical due to human presence disturbing elusive species which take refuge in remote forest regions. Leeches are therefore a great prospect for the future and a great advancement for conservation!

Frontier has been surveying elusive and threatened species in some of the world’s most unexplored forest and marine environments. Get involved in Conservation Projects in Cambodia, Costa Rica, Madagascar, Fiji or Tanzania, and contribute to some extremely valuable work. 

By Laura Burton