Region: East Asia/Pacific
J.
Tsogtbaatar1
and C. E. Goulden2
1Mongolian
Academy of Sciences
2Institute
for Mongolian Biodiversity & Ecological
Studies, Academy of Natural Sciences
The Government of Mongolia approved establishment of the Mongolian Long Term Ecological Research (MLTER) Network in December 1997.
Management: The Mongolian LTER Steering Committee, was organized in 1998, Dr. J. Tsogtbaatar of the Mongolian Academy of Sciences (geoeco@magicnet.mn) is the Director of MLTER. Dr. C. Goulden (goulden@acnatsci.org) is the International Coordinator.
Partnerships: MLTER is under the direction of the Mongolian Academy of Sciences with institutional support from the National University of Mongolia, The Ministry of Nature and the Environment of Mongolia, and The Academy of Natural Sciences of Philadelphia (USA).
Hovsgol National Park in northern Mongolia was designated the first MLTER network site in 1998, and was accepted as an East Asian ILTER site in 1998. Other potential sites are presently being considered and will include steppe grassland and desert sites. Monitoring and research programs have already started at Lake Hovsgol and are in the process of being designed at the other locations.
Goals: The primary goals of the Mongolian LTER Network are to study human impacts on Mongolia’s environment with a focus on short-term impacts of nomadic pasture use and forest loss due to cutting or fires on terrestrial and aquatic ecosystems. Climate change impacts are also a major component of the MLTER program.
Some conclusions and observations resulting from these studies to date include:
1. The Siberian larch (Larix siberica) dominates the forest, composing more than 90% of the trees.
2. The lake is surrounded by continuous permafrost.
3. HNP has many rare and endemic taxa. The level of endemism in the Lake is ca. 10% of the taxa of several phyla, but most taxonomic groups are poorly studied.
4. Endemic taxa compose most of the animal biomass of the Lake
5. Based upon phytoplankton biomass and primary production measurements, Hovsgol is an ultra-oligotrophic lake.
6. Because of the very low productivity, larch leaf detritus may be a primary source of food for aquatic invertebrates. Detritus can be carried deep into the lake by thermal density currents that mix the water in the spring from the shoreline areas.
7. The tributary streams have many endemic species of insects and are important spawning sites for the lake’s fishes.
Long-term monitoring programs at the Hovsgol LTER site
Meteorological and hydrological data are collected daily at the south and north ends of the Lake. The National Park has a chemistry laboratory and has monitored water chemistry of the Lake. In 1999 new equipment was purchased for analysis of water samples, and an improved water quality monitoring program was developed, which included study of the major tributary streams entering the Lake. Several long-term data sets will soon be available or are being obtained for the region and the Lake. Land cover maps from LandSat 4 satellite imagery are available, and new LandSat 7 imagery is now being used to develop more detailed land-cover maps for the region.
Impacts: Short-Term Impacts of Grazing and Fires
Grazing. The Hovsgol watershed primarily consists of taiga forest, but there are steppe grasslands bordering high alpine tundra in the west, and steppe on south-facing slopes of mountains. These areas have been grazed for centuries. Stream valleys are generally a combination of steppe vegetation and wetlands. Recently, the number of livestock in the valleys has increased because the loss of trade with Russia has limited the ability of the herdsman to sell their animals. This indirectly affects tributary streams of the Lake due to increased herd sizes. When grazing livestock move into grasslands they dramatically alter stream conditions. The erosion of stream banks is beginning to occur as grazing sheep, yaks, cows and goats move across streams more intensively.
Forest Fires. Natural fires now cause only an estimated 10% of the fires in Mongolia and Siberia; 90% of fires are due to carelessness or are deliberately set. Frequent forest fires change the course of plant succession in different ways, depending on topography, soil texture and moisture. Small trees less than 10 cm diameter and trees with high resin content are killed by even moderate fires.
Impacts: Long-Term Climate Change, Forest and Permafrost
Hovsgol LTER is strategically located for monitoring climate change. It lies just north of the transition between steppe forest zone and the taiga or boreal forest. Average annual air temperatures at the southern end of the Lake have increased by 1.44o C since 1963, as estimated by time-series analysis. Forest loss in northern Mongolia is widespread. The taiga forest as a whole is under similar threat; this is a serious global issue, the Siberian forest represents 20% of the forestry resources of the World. It is a major carbon “sink” for the whole Northern Hemisphere. Managing this phenomenon is crucial because the forest grows on permafrost soils that are being degraded by climate warming. Permafrost soils are high in humus content; loss of permafrost and warming of soils increases the rate of decomposition of humus, increasing the rate of release of carbon dioxide and methane, further increasing greenhouse gas levels in the atmosphere.
At Hatgal, preliminary studies indicate that the active zone depth has increased by 0.2-0.3 m, and permafrost temperature has increased by 0.1 to 0.2o C in the last 20 years (Tumurbaatar 1999).
The Mongolian Academy is planning to begin monitoring forest and steppe habitats, permafrost, soil conditions, and vegetation at the Lake beginning in 2000-2001. Nine watersheds with different human impacts will be selected as study sites in the summer of 2000-01, and monitoring and experimental studies will begin in 2001.