Comparative analysis of vegetation in the habitat of bonobos and chimpanzees using Landsat image.

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By using the landsat data and enumerating census of trees, we could distinguish several types of vegetation, including primary forest, secondary forest, and swamp forest. This information was useful for the analysis of vegetation use of chimpanzees and bonobos. The comparison between the landsat data and tree census enabled to estimate the vegetation type of the part of the home range for which we could not carry out the tree census. Thus this method appeared to be useful for the analysis of habitat use of the species whose home range is too large to cover by the actual vegetation census. We also developed an improved method of nest count for the estimation of density of chimpanzees. By this method, we could estimate accurate density of chimpanzees and the seasonal changes of their habitat use in a shorter period of research. Using these methods, we analyzed the habitat use by chimpanzees in the Kalinzu Forest, Uganda, Ugala area and Lukwa area in Tanzania, and bonobos in Wamba area and Hongo area in Democratic Republic of Congo. We found that the density of chimpanzees and bonobos are much different between the areas with different vegetation types, and that these animals largely shift their home ranges in different seasons. We also found that the combination of different vegetation types in a home range increases the density of chimpanzees and bonobos. Based on these information, we can identify some important factors influencing the habitat use by chimpanzees and bonobos, and can examine the inter and intra-specific differences in their habitat use in future studies. In this study project, we focused on the area where we actually visited and carried out the survey. However, this study using the landsat data opened a way to estimate the density of chimpanzees and bonobos in the wider area without the actual vegetation census.