Abstract
The Skylark Alauda arvensis is one of the most common grassland bird species in Japan. However, several reports suggest a decline in A. arvensis populations due to habitat loss, especially in urban areas. Therefore, factors affecting species distribution in relation to habitat preference in conservation planning must be evaluated. We did this by constructing habitat models to predict suitable breeding habitats for Skylarks in Tokyo using observation records collected in the 1970s and 1990s. The model predicted breeding occurrence in the 1970s and viability from the 1970s to 1990s using a GLM. Nine vegetation types and their combinations were used as predictor variables, along with a neighborhood effect. Our results showed that variables of aggregated 6 grassland types and the neighborhood effect significantly affected breeding occurrence in the 1970s. Viability was significantly affected by wet and dry grasslands in the 1990s. Since both models were relatively accurate, we applied the models to a map and revealed that 1) Skylarks were potentially widespread in Tokyo in the 1970s, and 2) grassland habitats along the rivers and coastline served as refuges in the 1990s due to the decrease in grassland habitat resulting from urbanization. Thus, conservation and restoration along the waterfront are imperative for Skylark viability in Tokyo.
