[an error occurred while processing this directive] [an error occurred while processing this directive]
ArcNews Online
 

Winter 2003/2004
Search ArcNews
 

E-mail to a Friend
Online Only Article

Ground Surveys and Satellite Tracking of Asian Elephants

Peter Leimgruber, Ph.D., and his team from the Smithsonian Institution's Conservation and Research Center (CRC) travel to Myanmar (Burma) for 10 to 14 days two to three times a year. For the fieldwork, they collaborate with the rangers and wardens in two of Myanmar's protected areas, Alaungdaw Kathapa National Park and Htamanthi Wildlife Sanctuary. The Burmese collaborators are dedicated to the conservation of elephants and work year-round under difficult conditions in the jungle. It's a hard life. The fieldwork is very dangerous, and the rangers are away from their families 80 to 90 percent of the time. The success of the conservation project depends on the year-round data collection by the rangers.

"We still have a lot to learn about the ecology of elephants in Myanmar and the closed forests of Asia," explains Leimgruber. "The ongoing fieldwork will help us gain a better understanding of Asian elephant ranges and how to preserve the species."

Ground Surveys

Two years ago, Leimgruber and his team trained the protected area forest rangers and wardens in surveying techniques to identify elephant populations in the wild. Because Myanmar's forests (choice habitat for Asian elephants in the region) are so rugged and dense, it is rare for a human to see an elephant in the wild. Instead, they count evidence of elephants—the dung. To perform these field surveys, the protected areas are divided into survey grids. Twelve Burmese staff members in each park walk approximately 250 to 350 km each season along trails looking for signs of elephants. For each dung location they collect a GPS coordinate, identify the habitat type, and determine how much dung was produced to determine its age. Based on this data, they can estimate how many elephants are in each of the survey blocks for each season. The habitat data is loaded into Microsoft Excel. The GPS data is imported to ArcView as an event theme and converted to a shapefile. Digital and hard-copy data is sent to CRC in Virginia for further analysis using forest cover maps derived from imagery.

"We will continue to collect data to improve the statistical confidence of our models," states Leimgruber. "However, we know that there should be more elephants in these areas and that the populations must have declined in the recent past. Our results are mapped and displayed with ArcView."

Satellite Tracking

Another ground survey method entails using a satellite-telemetry collar (www.telonics.com) to monitor wild elephant locations and identify their habitat selection. In December 2002, CRC began following Silver Moon (or Ngwe Thaw Dar in Burmese), a female Asian elephant who is part of a five-animal herd in the central part of Alaungdaw Kathapa National Park. A GPS unit is in the transmitter on the collar that Silver Moon wears around her neck. GPS points are collected two to three times a day at a 25-meter accuracy. The GPS data assists with locating the elephants in the park for visual observation and is used with imagery and GIS data to perform habitat analysis.

The Alaungdaw Kathapa National Park is an extremely inaccessible area. The topography contains steep slopes and during the rainy season it is very muddy, which makes moving about difficult. It would be virtually impossible for humans to follow an elephant herd without a tracking device. One could spend weeks trying to locate the herd and still not find it.

The GPS locations from the collared elephant are processed in ArcView. Asian elephant home ranges (the area an animal uses to satisfy its needs such as foraging for food, food resources, shelter, and mating) are calculated using Animal Movement, an ArcGIS Spatial Analyst extension from the U.S. Geological Survey (USGS). So far, the home range polygons show that the elephants are concentrated along streambeds in an area of approximately 100 square kilometers during the dry season. During the rainy season, their home range is approximately 400 square kilometers because water is more readily available.

"It is important," according to Leimgruber, "to assess how much area the Asian elephant requires and what types of habitat it really needs in order to determine the protected area needed to preserve a population for the long term. If a species declines beyond a certain size, there is inbreeding and other problems that can lead to rapid population extinction."

CRC also uses the Distance program, a freeware software tool to develop statistical estimates of population density and confidence intervals (www.ruwpa.st-and.ac.uk/distance), and the Animal Movement extension (www.absc.usgs.gov/glba/gistools).

For more information on spatial solutions, contact Leica Geosystems GIS & Mapping (toll free in the United States: 1-877-463-7327, outside the United States: 404-248-9000) or visit gis.leica-geosystems.com.

[an error occurred while processing this directive]