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一般研究成果リスト

Detail of Grant Awarded General Researches

Project

Research and Study for Restoring the Breeding Ground for the Tokyo Salamander in the Tama River Basin Satoyama

General
Research
No.212
Principal
Investigator
Noriko Hida
Affiliation Ome Frog Pond Project
Research
Summary
In FY2012, shelters for raccoon predation were developed and built, and then installed in the frog ponds. Automatic cameras with sensors were installed around the frog pond to collect image data of the animals using the frog pond.

Moreover, dredging of the frog pond (preservation and restoration of amphibian breeding environment) was implemented as a maintenance task, and a survey of Tokyo salamander egg sacs was implemented as a monitoring study.

Wolf urine, which is said to be an effective raccoon repellent, was set.

In FY2013, shelters for raccoon predation were improved and installed in the frog ponds; and, in continuation of FY2012, automatic cameras with sensors were installed around the frog pond to collect image data of the animals using the frog pond.

Furthermore, dredging of the frog pond (preservation and restoration of amphibian breeding environment) was implemented as a maintenance task, a survey of Tokyo salamander egg sacs was implemented as a monitoring study, and advice and evaluations for conservation measures were acquired from experts.

The number of Tokyo salamander egg sacs was 51 in 2012, 78 in 2013, about 1.5 times greater, and 166 in 2014, about 3 times greater, confirming the effect of dredging the frog pond (preservation, restoration and creation of amphibian breeding environment) and installing shelters.

From the images of the automatic cameras with sensors, it was observed that 10 species of mammals and four species of birds (raptores) used the frog pond.

Many of these images confirmed that raccoons entered the pond and preyed on frog larvae and adults and Tokyo salamander egg sacs by placing their front legs in the shelters. Accordingly, the number, design, and construction of the shelters must be reviewed.

By improving and increasing the number of shelters, we believe that the pressure due to raccoon predation can be reduced, but as a fundamental measure, raccoons should be captured and the rich regional ecosystem in which many native mammals live must be preserved and nurtured.
Collaborators Mamoru Kawamura Satoshi Sakuma
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