Author(s): Masatoshi Denda
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Abstract: The conservation of wild middle mammal populations is important for river ecosystems in Japan. Despite this importance, only limited methods (e.g. observation and diving surveys) are used for surveying and evaluating the populations, which has limited the progress made by Japanese studies. Such studies have clarified the behavior of wild middle mammal during the day and in the short term, but they have not clarified behavior at night and in the long term. We therefore aimed to quantitatively evaluate and model the behavior of wild middle mammal at night and in the long term by using individual-based models (IBMs) (Grimm V. 2006). First, we developed an advanced telemetry system (ATS) that could continuously track the long-term behavior of a wild animal to which a radio transmitter was attached. We focused and research on weasel as a typical species of wild middle mammal in the Kita River which flow down through east part of the Kyusyu Island. We used the ATS to conduct a field survey and track the wild middle mammal’s behavior during the day and at night for one month. We analyzed basic characteristics such as home range and spatial preference. In the results, the mammal went around in 1km2 area and mainly used vegetation area. Second, we analyzed the basic spatial preferences of wild middle mammal. Vegetation cover and vegetation community were estimated by image analysis of aerial photograph. In the results, the mammal used mainly deep vegetation areas and used temporally non vegetation and open area. Behaviors of the mammal were similar for one month after release. These behavioral characteristics and spatial preferences have not been reported before. Finally, we used IBMs to model wild middle mammal behavior by inputting data from this study and our previous studies. The IBMs represented long-term behavioral characteristics. Our ATS data were essential for accurate behavioral representation by the IBMs. By using these approaches, we developed basic evaluation tools for species conservation (Denda et. al., 2010). Our results indicated that interactions between measurement and simulation are needed to develop IBMs for evaluation and prediction aimed at conserving wild middle mammal populations.
Year: 2012