Cop’s weapon to track rogue plants

SOME species of plants, micro-organisms and animals often find their new environment so conducive for breeding that they soon begin to dominate native organisms. In doing so, these invasive species competitively exhaust both nutritional reserves as well as space for the native ones.

Though numerous efforts have been made by field ecologists to map the distribution as well as the dispersal pattern of these invasive species, they have not met with much success. The information is crucial to devise control methods.

Now a team of researchers from School of Biological and Chemical Sciences of University of London has used a computational method called geographical profiling for figuring out how the invasive species spread. For this, they used current locations of the invasive species as input and predicted its locations in the past.

The method is based on a statistical tool used to hunt down criminals. This tool links locations of the related crime to determine the most probable area of the offender’s residence. They found the method can work for nailing the species as police investigators and invasion managers face the same problems. Both have to deal with large volumes of data, and narrow down on the one which is informative within limited time.

For the study, the researchers analysed the spread of 53 invasive species over three decades using geographical profiling. These included all kinds of species including marine invertebrates and woody trees. To prove that geographical profiling works, the researchers compared their results with the data from the Biological Records Centre in Great Britain. The results showed that for 52 of these 53 data sets, geographical profiling was better than methods currently used for searching the source of invasive species.

“Geographic profiling could form a useful component of integrated control strategies relating to a variety of invasive species,” the authors wrote in the February issue of Ecography. It can also help identify invasion in early stages for more effective control.

Suhel Quader, member of Nature Conservation Foundation at Mysore appreciates the study. “It certainly does look more efficient than the other approaches. In- use methods are simple calculations that don’t incorporate any information about ecology like dispersal.” K Sivakumar, scientist at Wildlife Institute of India, Dehradun, suggests that since India has different biogeographical regions, identifying environmental factors that are conducive to their spread is also important.