Article ID: 23-00013
Understanding the historical processes of biodiversity degradation is essential for establishing goals and objectives for ecosystem restoration. In this study, records of local extinction of freshwater fish were collected from national and prefectural Red Data Books (RDBs), and the processes of biodiversity loss in Japanese local regions were investigated, taking into account the ecological and sociological backgrounds of inland water ecosystems specifically before the 1970s. The descriptions in RDBs were scrutinized, and information that directly or strongly indicated local extinction was extracted for each species or taxon. Additionally, causes and timings of local extinction were collected, if available, and compiled by decade. A total of 162 cases indicating local extinction were collected, and timing of local extinction was determined for 84.0％ of all cases, with 55.9％ of these last records occurring before the 1970s. Habitat degradation was the largest cause of local extinction (46.5％), followed by competition with and/or predation by exotic alien species (12.7％) and fragmentation from the sea (7.9％). Habitat degradation accounted for most of the causes of local extinction before the 1930s, fragmentation from the sea was 25.0％ in 1940, and competition and/or hybridization with closely-related alien species was 23.1％ in the 1950s. The causes of local extinction diversified after the 1960s. The use of pesticides and intensive catch for ornamental use increased from the 1960s to the 1970s and from the 1960s to the 2000s, respectively. Local extinction due to the invasion of exotic alien species increased after the 1960s and accounted for 21.9％ of the total cases from 1990 and later. The number of cases of local extinction peaked in the 1970s during Japanʼs high economic growth period, indicating explicit biodiversity losses of freshwater fish in this period. Although the rate of local extinction seems to have slowed after the 1980s, new concerns for biodiversity continue to arise. Therefore, implementing intensive measures for the maintenance and restoration of biodiversity is an urgent issue for achieving sustainability.
