Planning an ecological network using the predicted movement paths of urban birds

In this study, we propose a new method for planning ecological networks in Gangdong-gu, Seoul, Korea. The basic idea of this method is that, in urban areas where the price of land is high, it is most cost-effective to protect linear green areas that act as ecological corridors for potential movement paths (PMPs) of wild animals. PMPs were identified by a path-finding algorithm (PFA) that selected the optimum routes with minimum travel costs between pairs of locations where individuals of the indicator species-great tits (Parus major)-were found during field surveys. The PFA created an imaginary line segment network that connects nodes separated by 30 m across the entire study area, and estimated the total travel cost of a route from one P. major location to another by summing the travel costs associated with all of the segments comprising that route. We assumed that the travel cost of each segment is the average of the inverses of the bird densities at the two end nodes. For each node, the bird density was estimated from the linear relationship between percentage vegetation cover and bird density, as observed during field surveys. The predicted PMPs showed a pattern that was highly concentrated on patches with relatively high vegetation cover. The preference of P. major for a few specific routes allowed us to easily identify ecological corridors in the study area. An ecological network plan that protects and/or restores areas along ecological corridors would greatly improve the ecological connectivity of fragmented habitats in highly urbanized areas.