Mapping biodiversity data the DIVA way
The geographic distribution of agricultural diversity is an important consideration at all stages of genetic resource exploration and conservation, yet difficult to visualize and analyze. Software called DIVA-GIS gives mere mortals and diversity scientists the power to map.
- DIVA can predict where a species occurs (in red), using a 'climate envelope' for current or future climates.
How do you calculate the amount of biodiversity in an area? Many studies divide the target area into smaller areas of equal size (often squares in a grid), calculate a measure of diversity in each area and then compare that figure to the measure in the other units. There is software that can undertake the geographical part of such analyses but off-the-shelf packages can be expensive and difficult to learn.
In 2000, to address this need and others, Bioversity and the International Potato Center (CIP), with the financial support of the CGIAR's System-wide Genetic Resource Programme (SGRP), developed a package called DIVA-GIS. From the start, the intention was to give national plant genetic resources programmes and regional networks the tools they needed to assess the genetic diversity they were working with. Now in its sixth generation, the software is freely available to all users, along with tutorials. It has modules specifically tailored to the needs of scientists working in the field of biological diversity, giving them access to complex analyses at the click of a button and without the need for a GIS specialist.
"One feature of DIVA that is incredibly useful is the ability to find the geographic coordinates for a germplasm accession based on the description of where the accession was collected," enthused Andy Jarvis, one of the developers of the system. Geographic coordinates—latitude and longitude—are commonly missing from germplasm databases, but many accessions have a record of where they were collected, at least in terms of the name of the country and the name of the nearest town or village, often with additional details such as the distance and direction from the town or village to the collecting site. DIVA can use this information to estimate the geographic coordinates of the collecting site by searching a global database of place names to find the best match.
"I remember when we mapped a collection of 3000 peanut accessions by hand," said Jarvis with feeling, "looking up place names in atlases and on maps. It took us several months. Now you could do the same thing in DIVA in a matter of hours."
DIVA-GIS makes it easy to perform integrated analyses of biodiversity data, from mapping diversity to understanding species' environmental adaptations and predicting their distribution. It contains global datasets of present-day climatic variables and various projections through to the year 2055, as well as datasets on land cover, topography and population.
Thousands of people around the world are now using DIVA-GIS in a wide range of ways. A search on Google Scholar for "DIVA-GIS" found more than 100 publications in 2007 and 2008 that used or referred to the DIVA-GIS software, ranging from modelling the geographic distribution of invasive ant species in New Zealand to identifying regions of rapid diversification of mammals in California, with plenty of examples from the field of plant genetic resources. Analyses can help to guide germplasm conservation, from prioritizing areas for collecting missions to planning in situ conservation areas. DIVA-GIS can also be used to identify accessions that are likely to have particular environmental adaptations that could be fed into breeding programmes or distributed to farmers in anticipation of climate change.
What started out as a simple piece of software to map diversity in germplasm collections has now become a mainstay piece of publicly available software for biologists across the world.
Further information
