GIS analysis of the distribution dynamics of rare birds in Beijing.

In order to figure out the status of biodiversity restoration and distribution characteristics, we applied ArcGIS 9.3 software system to establish a GIS database for the ecological distribution of 66 species of birds under state key protection belonging to nine orders, and analyzed the distribution trend at different periods. The results showed that the overall distribution of the rare birds was concentrated around original forests with high quality vegetation, reservoirs and big rivers in mountainous areas, city parks and woodlands with less human disturbance in plain areas; however, there was no distribution in farmland areas. Comparing the ecological distribution sites of birds under State Key Protection Class I before and after the 1990s, it was found that the distribution was sparse, but three new species appeared after the 1990s, namely Chinese merganser (Mergus squamatus), brown eared pheasant (Crossoptilon mantchuricum) and relict gull (Larus relictus). Furthermore, the distribution sites of previous three orders expanded. The birds under State Key Protection Class II also had an expansion trend in distribution with two new species of the hazel grouse (Bonasa bonasia) and demoiselle crane (Grus virgo); however, the black tern (Chlidonias niger) and black-faced spoonbill (Platalea minor) could not be found. The above results revealed that there is a positive recover for the overall distribution of the rare birds with the restoration of forests and wetlands in Beijing. The fact that some species disappeared recently indicated that protection of the habitat of wildlife is still a long-term process of constructing ecological environment. The GIS database lays the groundwork for building the management platform of rare wild animal distributions in Beijing, and possesses the important applicable value for the measures of protecting the wild animal populations and their habitats at landscape level.