Worldwide Survey Assesses Biodiversity Beneath Our Feet

BOULDER, Colorado, November 1, 2001 (ENS) - Over the next two months, scientists at 32 sites in 20 countries will dig through bags of leaf litter to learn more about the tiny creatures which perform one of nature's most important jobs - decomposition. The researchers are part of the first global survey of the biodiversity in the plant debris which blankets much of the planet's surface.

leaf litter

One of the leaf litter bags used to collect samples for the biodiversity survey (Photo by Mark Harmon, courtesy GLIDE)
As part of the Global Litter Invertebrate Decomposition Experiment (GLIDE), last August and September the researchers placed mesh bags of leaf litter on the ground of diverse ecosystems, from tropical to boreal forests, and from to savannahs to arctic tundra. In November and December, they will retrieve some of these bags for analysis of global patterns of decomposition and the species involved.

The chair of GLIDE, Dr. Diana Wall of Colorado State University, expects the study to advance the team's understanding of large scale distributions of the tiny animals that dwell in soil and litter. Even at small scales, biodiversity in soils and litter is poorly known.

There is not one experimental plot, anywhere in the world, for which all species of soil and litter creatures have been described. The dearth of information on these species is partly due to their sheer abundance and diversity.

"The species diversity of fauna in litter and soil is likely to be orders of magnitude greater than the more familiar biodiversity aboveground," said Wall. "Furthermore, there may be hundreds of species and thousands of individuals in a handful of soil or litter. Collecting and identifying such large numbers of species poses an enormous challenge to soil taxonomists."

Wall explained that the majority of these species are not visible to the naked eye since they live in dark underground habitats, and many are microscopic. Biologists estimate that for many soil and litter taxonomic groups, less than 10 percent of species have been scientifically described.

zerconid

The Oregon zerconid, a microscopic mite, lives in leaf litter and preys on other small creatures (Photo by Dr. David Walter, courtesy GLIDE)
Despite limited knowledge about the identity of individual species of soil and litter habitats, soil biologists know that groups of these species play crucial roles in the functioning of ecosystems, including decomposing organic matter and recycling nutrients to the soil.

Lack of information on how the identity and diversity of species varies across habitats, and influences ecosystem processes, limits scientists' ability to assess how changes in habitats - such as deforestation and climate change - may alter communities of litter creatures and vital ecosystem processes.

"The enormous resources required to survey belowground biodiversity has prohibited assessments across multiple biomes in the past," Wall explained. She and her colleagues are using creative approaches to make this first global scale assessment of litter biodiversity possible.

The team is benefiting from the participation of international networks that provide extensive geographical coverage, baseline data, expertise and equipment. Participating networks include the Canadian Intersite Decomposition Experiment (CIDET), International Long-Term Ecological Research (ILTER) program, Long-Term Intersite Decomposition Experiment Team (LIDET) and the Tropical Soil Biology and Fertility (TSBF) program.

The researchers will use state of the art technology called BioTrack to the taxonomic identification of the tens of thousands of individual animals they expect to find. BioTrack, directed by GLIDE co-chair Dr. Mark Dangerfield at Maquarie University Australia, scans each specimen and creates a high resolution image. Computer software then compares the image with a virtual collection to provide a match and identify the specimen.

ostracod

Most of the tiny crustaceans called ostracods live in water. The Queensland terrestrial ostracod is a rare example of a land living ostracod, making its home in damp leaf litter in Australia (Photo by Dr. David Walter, courtesy GLIDE)
All of the scientists participating in the project are volunteering their time to place the litterbags in the field and collect them.

The researchers expect that within a year GLIDE will yield unprecedented data on the animals involved in various stages of litter decomposition across different habitats and latitudes. This information will help answer important questions such as how significant the diversity of litter creatures is for the functioning of ecosystems and how it is influenced by their environment.

More Information on the IBOY Project Global Litter Invertebrate Decomposition Experiment (GLIDE) is available at: http://www.nrel.colostate.edu/projects/glide/