[Breeding habitat characteristics of red-crowned crane at Zhalong of Northeast China: a multi-scale approach based on TM and ASAR image data].

Based on the Landsat TM and Envisat ASAR HH/HV imagery data and by using the GPS data of red-crowned crane nesting sites (n = 28) at Zhalong National Nature Reserve of Northeast China, the models of the breeding habitat selection of red-crowned crane at the Reserve were established by binary Logistic regression to identify the key variables for the habitat selection at eight spatial scales (30-240 m). The relative performance of the two models based on the Landsat TM and Envisat ASAR HH/HV databases was compared, and the prediction capacity of the models across the eight scales was approached. The overall precisions of the two models were satisfactory (> or = 69.0%). At scale 30 m, only variable TCA_2 entered with negative value into the model based on Landsat TM database, which indicated that the crane at this scale avoided selecting higher density reed marshes. At scales 60-120 m, the variable PCA_2 entered with positive value into the two models, indicating that the crane at these scales had higher demand of high density reed marshes to improve its concealment. At scale 90 m, the variable HV backward scatting coefficient also entered into the combined model, which indicated that water condition was the important factor for the habitat selection of the crane at this scale. At scales > 120 m, the texture information of the two satellite sensors started to be involved into the two models, indicating that at larger scales, the crane had decreasing demand on the vegetation features for its breeding habitat selection but increasing sensitivity to the anthropogenic disturbance factors. The introduction of ASAR variables into the models increased the prediction accuracy of the models markedly at all scales.

[Spatiotemporal dynamics and landscape pattern of alien species Spartina alterniflora in Yancheng coastal wetlands of Jiangsu Province, China].

Based on the 1992-2007 remote sensing images and field survey data, and by using the landscape ecology theories and the method of conversion matrix, the spatiotemporal dynamics and landscape pattern of Spartina alterniflora in Yancheng coastal wetlands were analyzed by GIS. The results showed that the total area of S. alterniflora along the whole coastal beaches of Yancheng increased from 3561 hm2 in 1992 to 14491 hm2 in 2007, with a growth rate of 306.94%. In 1992-2007, the total area of S. alterniflora conversion-in and conversion-out was 26291 hm2 and 15361 hm2, respectively, and the S. alterniflora community in the core area of Yancheng National Nature Reserve expanded from 597 hm2 to 2814 hm2, with an annual growth rate of 24.74%. The S. alterniflora community transformed from scattered patches in estuarine regions into continuous belt pattern mainly distributed in the periphery of coastal wetlands from Sheyang River to Liangduo River. Its centroid moved to the southeast, with a distance of 2.92 km. The average area of patches increased from 1992 to 2002, and then decreased from 2002 to 2007. The largest patch index and area-weighted contiguity index increased year by year, and the shape of patches tended to be more regular.

[Impact of habitat evolvement and human disturbance on wintering water birds in Shengjin Lake of Anhui Province, China].

From October 2002 to April 2003, investigations were made at six monitoring sites with different degrees of human disturbance and habitat quality in Shengjin Lake to understand the impact of human disturbance and habitat evolvement on the distribution patterns of wintering water birds. The results showed that in the same wintering period, the species richness and population size of water birds at different sites had no significant correlation with habitat quality but significantly negatively correlated with human disturbance degree, while in different years, these two parameters were strongly correlated to habitat quality. The major threats to the water birds in Shengjin Lake were habitat loss, human disturbance and biocides, in light of which, corresponding protection measure were put forward.