2023 Volume 17 Pages 1-15
About 40% of hundreds of reservoirs in Nagano City, Nagano Prefecture, which are habitat for the endangered Pseudorasbora pumila, have been abandoned and are predicted to rapidly deteriorate in the future. In a survey lasting from 1996–2010, 36 ponds were assessed using eight variables to determine the habitat status of each pond. Of the 36 ponds, 33 were determined to meet the habitat requirements by P. pumila. A total of 29 ponds were confirmed to be inhabited by P. pumila. Presence of P. pumila were reconfirmed in twenty-seven ponds and were newly discovered in two ponds. Ponds where P. pumila could not be captured were found to be significantly deteriorated due to abandonment. Local extinctions of P. pumila are a concern as more ponds with P. pumila habitat are abandoned. In order to efficiently conserve a large number of P. pumila habitat ponds, we established a conservation priority using eight variables. By using these eight variables, we evaluated the importance of each population and the urgency of each pond's management status. With this we devised a conservation priority ranking system from 1st to 9th. Using this conservation priority ranking system can help to efficiently allocate management costs such as the frequency of monitoring surveys and the maintenance and repair of abandoned reservoirs. Because it will be increasingly difficult to resolve the conservation of rare species within the region it is important to build a new pond management system from a long-term perspective. While using the new pond management system, it is important to share knowledge about the relationship between farming and conservation of rare species to a wide range of stakeholders, including not only local residents but also urban dwellers.
