Bird Life Tieng Anh-01.qxd - Birdlife International in Indochina

and Sonobe and Usui (1993). Additional information on threats to biodiversity was obtained through
interviews with local people, border soldiers, district officials and site managers.
2.3 Vegetation surveys
Vegetation-type boundaries were plotted for each site and survey transects defined to sample all
major types. Surveys were carried out by boat or on foot and methods included direct observation
and sampling of plant communities, and interviews with local people. Photographs were taken of
each vegetation type, and notes taken on plant composition and density at each location.
Plant lists were compiled using data from a 1996 survey (Pedersen and Nguyen Huy Thang 1996).
Some species were identified and marked in the field, others were photographed and dry specimens
brought to Hanoi for identification by morphological comparision with literature sources (Lecomte
(eds.) 1907–1937, Humbert (ed.) 1948–1950, Anon. 1972–1976, and Pham Hoang Ho 1999–2000).
2.4 Site mapping methodology
2.4.1. Materials and software
1:50,000 Topographic maps.
MapInfo version 6.0, Microsoft version 4.3. Garmin GPS 12Xl.
Landsat TM7 Satellite Image, 2003.
2.4.2. Image classification
Landsat TM7 Satellite Images from 2003 were visualised and classified with each polygon coded.
Habitat maps were constructed using the coded polygons and ground truthed using transects and
survey points. Datasheets were used to collect information in the field, and digital photographs were
used to help construct the maps. Information on previous and changing land-uses in the area was
obtained by interviewing local people.
2.4.3. GIS methods
A Geographical Information System (GIS) was used to combine textual and spatial data. Final
habitat maps were constructed using the overlay and thematic mapping functions of MapInfo version
6.0 and six maps were generated, covering sites between An Hai, Hai Phong city and Nghia Hung,
Nam Dinh province.
3. Results
3.1 Literature review
The most comprehensive biodiversity study on the coastal wetlands of the Red River Delta was
conducted in 1996 by the BirdLife International Vietnam Programme in collaboration with the
Forest Inventory and Planning Institute (FIPI). Results were presented in Technical Report No. 8
of BirdLife Vietnam, entitled The conservation of key coastal wetland sites in the Red River Delta
(Pedersen and Nguyen Huy Thang 1996). The report identified seven key wetland sites for
biodiversity conservation in the Delta; Thuy Nguyen District, Van Uc Estuary, Thai Binh Estuary
(Tien Lang District), Thai Binh Estuary (Thai Thuy District), Tien Hai Nature Reserve, Xuan Thuy
Nature Reserve (now a National Park) and Nghia Hung District.
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