| Between April 2006 and January 2007, we surveyed 20 islands for birds and 40 islands for lizards in the Thousand Island Lake region by line-transect sampling. Combined with the plant richness from surveyed data, species life-history traits of birds and lizards (including body length, geographical range size, habitat specificity and area of minimal distributed island) from the references, and the landscape parameters from GIS analysis, we analyzed and compared the nestedness of the two faunas and the factors affecting their patterns by using the software "BINMATNEST (binary matrix nestedness temperature calculator)" and the Spearman rank correlation analysis. We evaluated the influence of the habitat characteristics including island area, isolation, plant richness, and the species life-history traits on forming the nested patterns. Furthermore, we compared the nested structure and its cause between the birds and lizards, between the Passeriformes birds and non-Passeriformes birds.The results showed that the birds had significant nested pattern on the islands and its nested ranking were significantly correlated with the island area and plant richness. In the species life-history traits, body length and the area of the smallest island occupied by a species were highly correlated as well. The Passeriformes birds had higher nestedness and stronger correlation with habitat characteristics than non-Passeriformes birds. Moreover, the comparing analysis of species-area relationship curve between mainland and islands suggusted that Selective Extinction did happened in birds on the islands.For the lizard, the significant nested pattern was also found on the islands. Butonly two variables, the island area and the area of the smallest island occupied by aspecies, were significantly correlated with its nested pattern.Comparing the nested pattern between birds and lizards, we found that the lizards had higher nestedness as birds had stronger dispersal ability, a facor related negatively to selective extinction. It meant that the dispersal ability and spacial scale might be the major factors to determine the difference of nestedness of birds and lizards. In addition, we also found that the accompanying relationship of variables between the habitat characteristics and the species life-history traits exited in the nested patterns of the birds and lizards respectively, which suggested that both the habitat characteristics and the species life-history traits had important contributions to nested patterns in birds and lizards on the islands in the Thousand Island Lake region.For conservation applications, we thought that the large islands with high plant richness, the species with large range size requirement, and birds with high habitat specificity should be payed more attentions on when making conservation action plans in our study area. Moreover, some composed islands with low isolation should also be protected effectively as the composed islands are particularly important for the non-Passeriformes birds to persist on the isolated small islands. |
