Identification of potential habitats of gray-faced buzzard in Yatsu landscapes by using digital elevation model and digitized vegetation data

Potential habitats of gray-faced buzzard (Butastur indicus), one of the umbrella species in agro-forested landscape in Japan, were identified in this study based on a precise landscape classification of small valleys called Yatsu, using 50 m-grid digital elevation model and digitized vegetation data. This study mainly consists of two phases: the first is to identify and classify the landscape structure of small valleys, and the second is to identify potential habitats of gray-faced buzzards, one of the umbrella species in this landscape. In the first phase, landscape types around Yatsu valleys in the study area were classified into four types based on the land-use patterns in the cross-sectional direction of valleys. Traditional landscape pattern of rice paddies in the valley floor with wooded slopes are now very scarce at under 10%, over 60% of the valleys in the study area are now without rice paddies in valley floor. Rice paddies on the valley floor and the juxtaposition of paddies and woods are known to be an important habitat for many species based on previous field studies. In the second phase, the characteristics of gray-faced buzzard habitat were identified as follows: (1) narrow valley floor, (2) rich accumulation of edge environments between rice paddies and woods, (3) rich accumulation of landscape pattern with rice paddies in valley floor, and with woods on both slopes in the cross-sectional direction of valleys. Based on the identified characteristics of Yatsu landscape, the potential habitats of the buzzard were identified in the study area.