PHYSICAL GEOGRAPHY AND HYDROLOGY

PHYSICAL GEOGRAPHY AND HYDROLOGY

The Bat Dai Son Mountain area is identified in current assessment as the region of properly the Bat Dai Son Mountains with hilly and mountainous territories allied to these Mountains from the west and the south. The administratively assessed area belongs to Quan Ba District (Bat Dai Son, Can Ty, Cao Ma Po, Ta Van, Thai An, Thanh Van, and Tung Vai communes) of Ha Giang Province. Geographically it occupies the northernmost angle of northern Vietnam allied to the Chinese border (Fig. 1) and belongs to the northern part of the Northeast region according to the state governmental classification (Northeast – Vietnam. Wikipedia, 2020). The total square of Quan Ba District is 550 км2. The district capital is Tam Son Town. The district population (General Statistics..., 2020) was estimated as 44506 for 2009 (39821 in 2003). Following straight extrapolation, the present population is over 60000, but most probably is a bit higher. About 80–90% of people in the Bat Dai Son Mountain area belong to H'Mong, Tay, Dao, Nung, and Lo, and some other ethnic minorities still holding their true identity. The Kinh (true Vietnamese) people present the rest population. Quan Ba is a rural district, and traditionally, the vast majority of people’s economic activity here revolved around agriculture and forestry (Ha Giang Province. Wikipedia, 2020). Agricultural and deforested areas in Quan Ba District were considerably expanded during the last years and occupy at present approximately 40–50% of overall district territory (Fig. 2).

According to the data of the Department of Nature Conservation Vietnam Administration of Forestry (Ministry of Agriculture and Rural Development of Vietnam) total area of the Bat Dai Son Nature Reserve at present is 55.34 km2 (Protected Planet, 2020). The territory of the nature reserve extends in the form of an elongate polygon from the Chinese border in SE direction along the right side of the Song Mien River to about 12 km. Its broadest part is about 5 km wide at the middle (Fig. 3, 4).

Various orography, mosaic composition of parental rocks, and many kinds of landforms are very typical for the studied area (Fig. 2). In broad sense, the Bat Dai Son Mountains and allied areas represent integral biogeographic territory, which lies in the watershed of Song Lo and Song Mien rivers (Fig. 3A). These are the largest rivers of Ha Giang Province flowing into Vietnam from China. Hydrological net between these rivers is well developed and includes many of their tributaries in a form of many small rivers and streams. In karstic limestone fields, they form a series of specific habitats with unique azonal plant and animal communities.

Soure: Averyanov L.V., K.S. Nguyen, T.H. Tran, A.L. Averyanova, T.V. Maisak, H.T. Nguyen. – Plant diversity, flora and vegetation of Bat Dai Son Mountain area, northern Vietnam –– Saint-Petersburg, STRATA, 2020 — 561 p