Spatial pattern of nest-site of Grus japonensis in Zhalong National Nature Reserve

Zhalong National Nature Reserve locates in the western part of Northeast China, the western part of the Songnen Plain, the downstream of the Wuyuer River, has 210 000 ha area of wetlands that provide habitats for the Grus japonensis and many other waterbirds. Spatial pattern characteristics of Grus japonensis nest - site in Zhalong National Nature Reserve was focused on in the paper. On the basis data of Grus japonensis nest - site distribution in Zhalong National Nature Reserve in 1996 and from 2003 to 2007, centroid distribution and spatial discrete degree of nest - site, and the relationship between nest - site and reed swamps based on the elevation and slope, were studied. The result showed that the centroid of nest - site of Grus japonensis in Zhalong National Nature Reserve mainly distributed in the core area without the serious interference; centroid deviation each year mostly occurred on the inside of the core area. But the nest - sites centroid of Grus japonensis almost moved out of the core area in 2005 because of the inference of fire. Before 2005, the distance between the nest - sites of Grus japonensis reduced year by year, and increased after 2005. 92.03% Grus japonensis nest-site distributed the elevation range from 142 m to 148 m, and 82.04% reed swamps distributed the same range; 90.93% Grus japonensis nest-site distributed the slope of smaller than 0.25, and 87. 31% reed swamps distributed that slope range. The distribution of reed swamps and Grus japonensis nest - sites had a strong correlation on elevation and slope, it indicates that reed swamps was important habitat of Grus japonensis.