Priority maps for protecting the habitats of threatened freshwater fishes in urban areas: a case study of five rivers in the Fukuoka Plain, northern Kyushu Island, Japan

Onikura, Norio; Nakajima, Jun; Inui, Ryutei; Kaneto, Jun

doi:10.1007/s10228-015-0504-5

Cited by 8 publications

(4 citation statements)

References 22 publications

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“…Distributional information on threatened species is often used for the complementary selection of conservation and restoration sites (Caro & O'Doherty, 1999; Lawler et al, 2003), and the same procedure is also applied in Japan (e.g. Inui et al, 2016; Naoe et al, 2015; Onikura, 2015; Onikura, Nakajima, Inui, & Kaneto, 2016; Yoshioka, Akasaka, & Kadoya, 2014). The distribution data of threatened and near‐threatened species listed by the Ministry of the Environment (2017, 2018) were extracted for our dataset.…”

Section: Methodsmentioning

confidence: 99%

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Differences in conservation candidate tidal rivers by cross‐taxon analysis in the Japanese temperate zone

Inui

Kanno

Eguchi

et al. 2020

Aquatic Conservation

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1. For effective biodiversity conservation, verifying the correspondence of conservation sites among taxa and identifying the environmental characteristics of these sites are essential; however, only a few such studies have been performed in estuaries. The aim of the present study was to verify the surrogacy of estuarine gobies and crabs, to identify tidal rivers of high conservation priority, and to describe their environmental characteristics. 2. Distribution data for gobies and crabs were collected from 158 tidal rivers in the Kyushu region, Japan. Three conservation scenarios were analysed based on the distribution data of gobies alone, of crabs alone, and of both taxa, in order to assess the correspondence of the conservation candidates (i.e. tidal rivers) between taxa. 3. The degree of correspondence was poor for the candidates selected on the basis of the distribution data of gobies or crabs separately. More efficient candidates were selected based on the data for both taxa. The environmental characteristics of tidal rivers with high irreplaceability for conservation differed between the taxa. Tidal rivers forming and maintaining large tidal flats covered with fine sediment might have high irreplaceability for goby conservation, whereas rivers with saltmarshes connected to supratidal and intertidal zones might have high irreplaceability for crab conservation. 4. Tidal rivers with a high priority for conservation were identified by overlapping the candidates for three scenarios. These tidal rivers are not necessarily large, but have steep basins with river mouths that are less exposed to ocean waves. Moreover, the percentage of artificial areas in these rivers was low, suggesting that these rivers have not been exposed to excessive anthropogenic disturbance that leads to loss of estuarine habitat. 5. These results show that gobies and crabs are not surrogates for one another.

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Section: Methodsmentioning

confidence: 99%

“…There are two methods for selecting conservation areas: based on actual distribution data (e.g. Inui et al, 2016; Onikura et al, 2016) or on potential distribution data estimated by species distribution models (e.g. Carvalho, Brito, Crespo, & Possingham, 2011; Naoe et al, 2015).…”

Section: Methodsmentioning

confidence: 99%

Differences in conservation candidate tidal rivers by cross‐taxon analysis in the Japanese temperate zone

Inui

Kanno

Eguchi

et al. 2020

Aquatic Conservation

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“…Japan is a mountainous, wet, and forested country with a rich freshwater fauna and a high proportion of endemic species (Yoshimura et al, 2005). However, people are concentrated in densely populated urban areas along the coast and on alluvial plains, and recent urbanisation has destroyed and degraded natural freshwater habitats, and now most unionid species are endangered (Kondo, 2008;Negishi et al, 2008;Onikura et al, 2006Onikura et al, , 2016. Due to coextinctions, 15 of the native 16 species/subspecies of bitterling fishes are also endangered and are listed on the Japanese Red List (Ministry of the Environment, Japan, 2013).…”

Section: Introductionmentioning

confidence: 99%

Decline of unionid mussels enhances hybridisation of native and introduced bitterling fish species through competition for breeding substrate

2020

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1. Bitterling fishes (Subfamily: Acheilognathinae) spawn in the gills of living freshwater mussels and obligately depend on the mussels for reproduction. On the Matsuyama Plain, Japan, populations of unionid mussels-Pronodularia japanensis, Nodularia douglasiae, and Sinanodonta lauta-have decreased rapidly over the past 30 years. Simultaneously, the population of a native bitterling fish, Tanakia lanceolata, which depends on the three unionids as a breeding substrate, has decreased. Furthermore, a congeneric bitterling, Tanakia limbata, has been artificially introduced, and hybridisation and genetic introgression occur between them. Here, we hypothesised that decline of the unionids has enhanced this invasive hybridisation through competition for the breeding substrate. 2. Three study sites were set in three streams on the Matsuyama Plain. We collected adult bitterling fishes (native T. lanceolata, introduced T. limbata, and foreign Rhodeus ocellatus ocellatus) once a week from April to October 2013 to measure their densities in streams and to examine seasonal differences in female ovipositor length, which elongates in the breeding season. Simultaneously, we set quadrats and captured unionids and measured environmental conditions. Each unionid individual was kept separately in its own aquarium to collect ejected bitterling eggs/ larvae. Tanakia eggs and larvae were genotyped using six microsatellite markers and the mitochondrial cytochrome b gene. 3. Introduced T. limbata was more abundant, had a longer breeding period, and produced more juveniles than native T. lanceolata. Hybrids between the two species occurred at all sites, and in total 101 of the 837 juveniles genotyped were hybrids. The density of P. japanensis was low, at most 0.42 individuals/m 2. Nodularia douglasiae and S. lauta have nearly or totally disappeared from these sites. Hybrid clutches of Tanakia species occurred more frequently where the local density of P. japanensis was low. Mussels were apparently overused and used simultaneously by three species of bitterlings. 4. Decline of freshwater unionid populations has enhanced hybridisation of native and invasive bitterling fishes through increasing competition for breeding substrate. We showed that rapid decline of host mussel species and introduction of

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“…Bitterling fishes of the family Cyprinidae inhabit rivers, agricultural ditches, and small ponds, and breed by depositing eggs in the gills of freshwater bivalves [7,8]. In Japan, 15 of the 16 native bitterling species and subspecies are listed on the Japanese Red List, facing extinction crises due to multiple stresses, the most critical of which are habitat loss from urbanization, river improvement, and the consequent decline of unionid bivalve populations [9,10,11,12]. The introduction of alien species is another factor negatively impacting native species.…”

Section: Introductionmentioning

confidence: 99%

Hybridization between an endangered freshwater fish and an introduced congeneric species and consequent genetic introgression

et al. 2019

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Artificial transplantation of organisms and consequent invasive hybridization can lead to the extinction of native species. In Matsuyama, Japan, a native bitterling fish, Tanakia lanceolata , is known to form hybrids with another bitterling species, T . limbata , which was recently introduced from western Kyushu, Japan. These bitterlings spawn in the gills of two freshwater unionid species, Pronodularia japanensis and Nodularia douglasiae nipponensis , which have rapidly declined on the Matsuyama Plain in the past 30 years. To gauge the effect of invasive hybridization, we determined the genetic introgression between T . lanceolata and T . limbata and analyzed the morphology of these species and their hybrids to infer their niche overlap. We collected adult individuals of Tanakia spp. and genotyped them based on six microsatellite loci and mitochondrial cytochrome b sequences. We analyzed their meristic characters and body shapes by geometric morphometrics. We found that 10.9% of all individuals collected were hybrids. Whereas T . lanceolata were more densely distributed downstream and T . limbata were distributed upstream, their hybrids were widely distributed, covering the entire range of native T . lanceolata . The body height and anal fin length of T . limbata were greater than those of T . lanceolata , but their hybrids were highly morphologically variable, covering both parental morphs, and were widely distributed in the habitats of both parental species. Hybridization has occurred in both directions, but introduced T . limbata females and native T . lanceolata males are more likely to have crossed. This study shows that invasive hybridization with the introduced T . limbata is a potential threat to the native population of T . lanceolata via genetic introgression and replacement of its niche in streams.

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Priority maps for protecting the habitats of threatened freshwater fishes in urban areas: a case study of five rivers in the Fukuoka Plain, northern Kyushu Island, Japan

Cited by 8 publications

References 22 publications

Differences in conservation candidate tidal rivers by cross‐taxon analysis in the Japanese temperate zone

Differences in conservation candidate tidal rivers by cross‐taxon analysis in the Japanese temperate zone

Decline of unionid mussels enhances hybridisation of native and introduced bitterling fish species through competition for breeding substrate

Hybridization between an endangered freshwater fish and an introduced congeneric species and consequent genetic introgression

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