Nature

Ba Be National Park lies in the Tropical Southern China area of the Indo-Malayan Realm. This region is characterised by steep limestone mountains, interspersed by lowland non-limestone areas. The underlying geology of the national park is limestone with topography being strongly separated and comprising many high mountain peaks, steep hill slopes, caves, valleys, streams and rivers. Ba Be Lake, which the national park is centred upon and after which it is named lies at 150m above sea level and the surrounding mountains rise up to 1,098m above sea level. The lake is mainly fed by the Ta Han, Cho Leng rivers and Bo Lu rivers.

Vegetation coverage mainly includes two types of forests: limestone and evergreen forests. Limestone forests are distributed on steep mountainsides where the soil is thin and cover most of the park area. Evergreen forests are distributed on low earthen hills covered with a thicker soil layer. The species diversity of the lowland evergreen forests is usually more diverse than those found on limestone mountains. The dominant limestone species include the threatened Burretiodendron hsienmu, Streblus tonkinensis among which climbing bamboo (Ampelocalamus sp) is endemic to the region and often found on hill slopes that lie adjacent to the lakeside.

The forests play an important role in watershed protection. Without this mosaic of plants, the land could likely be eroded due to intensive water flows and water restoration of the lake could therefore be weakened in the flood season. This would cause drought and flood every year, which threaten the lives of local communities in downstream of the Nang river.

Of the fauna in the national park, the most important mammal species for conservation are the Francois’ langur (Trachypithecus francoisi) and Owston’s Banded Civet (Hemigulus ownstoni). The Francois' Langur was first found in 1995 along the second bank of Ba Be Lake and, in 2001 rediscovered nearby along the Nang River.

The Vietnamese Salamander (Paramesotriton deloustali) was recently discovered in streams in the buffer zone of the national park. These were the first records for this endemic species outside of Tam Dao National Park and considerably extended its range.

The national park is also notable for its considerable butterfly diversity, for which to date over 300 species have been recorded.

Without doubt, the national park plays an important role in wetland biodiversity and habitats conservation, in particular for freshwater fish, including several species listed in the Red Data Book of Vietnam.

Ba Be Lake

Ba Be Lake is Vietnam’s largest and highest, natural freshwater lake, situated at about 150m above sea level. Ba Be actually means ‘three lakes’ (‘Slam Pe’) in the local Tay language, the ‘lakes’ being Pe Leng, Pe lu and Pe Lam. This is an ancient name that refers to the way that the lake comprises three relatively wider sections. Ba Be is however a continuous body of water with numerous small inlets and islets, stretching for nearly 8 kilometres north to south. Due to this rugged splendour Ba Be is sometimes referred to as the ‘Ha Long Bay of the mountains’. The depth of the lake is between 17 and 23m on average, with the deepest point about 35m deep. The surface area of the lake fluctuates between 300 and 500 ha depending upon the season and unlike most lakes in karst limestone landscapes, Ba Be Lake remains full all year round.

Hydrology

The lake is fed by the Ta Han, Bo Lu and Leng Rivers from the south and west, then drains into the Nang River in the north. During high floods in the wet season, water from the Nang River also flows into the lake. In this way, the lake also plays an important role in regulating flooding. The tectonic movements that lead to the formation of the shallow Nang River, caused it to form a dam leading to the formation of the lake. Due to this constant in-flow and out-flow, the water in Ba Be Lake is always in motion, therefore never becoming stagnant and remaining clean.

Lake biodiversity

* Fish

Ba Be Lake can be considered to be one of the richest natural lakes for fish biodiversity in Vietnam. To date 106 species of fish have been recorded in Ba Be Lake, belonging to 61 genera, 17 families and 5 orders. Twenty species have not recorded since the 1970s and can be considered extinct from the lake.

The lake's fisheries are an important part of the diet for local people. Almost every day people can be seen fishing the lake from the traditional dugout ‘Doc Moc’ canoes. Long nets are suspended a few metres below the surface of the lake from floats made of sections of bamboo. Sections of bamboo seen floating on the lake are also being used for this purpose.
Threats to fish diversity

Recent fishing practices have threatened the fisheries and probably caused the decline in fish diversity. Dynamite and electric fishing kill fish indiscriminately and to a greater extent than is necessary. These practices are illegal throughout Viet Nam and have been curtailed in Ba Be Lake by greater surveillance and by severing socio-economic assistance provided in exchange for activities that help protect the biodiversity. The use of lift nets has also been prohibited.

Local fishermen have also been given training on more sustainable fishing techniques and the value of the biodiversity in the lake. Sometimes a small piece of knowledge can have a big effect. Increasing the mesh size of nets allows young fish to remain free to grow into adults and reproduce, while the fishermen can still catch the more valuable adults. Most significantly the formation of a Lake Management Cooperative comprising fisherman from local communities and the national park has led to greater cooperation to sucessfully address these issues.

* Algae

Until now, 179 species of phytoplankton belonging to Chorophyta, Cyanophyta, Bacillariophyta, Euglenophyta, Pyrrophyta and Chrysophyta have been recorded in Ba Be Lake. Chlorophyta being the dominant family with 71 species. A remarkable number of Bacillariophyta have also been recorded, reflecting the fact that Ba Be Lake is located in a mountainous region. The presence of the freshwater red algae Batrachoprmum sp. belonging to Rhodophyta is very important and under certain conditions gives the lake water a red colour.

Ethnologie

Ba Be National Park is home to over 3,000 people from five different ethnic groups. For over 2,000 years, Ba Be has been inhabited by Tay people, who make up the majority. Nung and Dao people may have arrived about 100 years ago and Kinh and Mong are relatively recent arrivals.

There are 13 villages in the national park, some of which are almost exclusively inhabited by one ethnic group as shown in a map of villages around Ba Be National Park. Usually, Tay villages are situated in low-lying areas, Dao villages at mid-elevations and Mong villages in the uplands.