The threatened status of restricted‐range coral reef fish species

Abstract

Coral reefs are the most diverse ecosystem in the sea. Throughout the world they are being overfished, polluted and destroyed, placing biodiversity at risk. To date, much of the concern over biodiversity loss has centred on local losses and the possibility of global extinction has largely been discounted. However, recent research has shown that 24% of reef fish species have restricted ranges (< 800 000 km 2 ), with 9% highly restricted (< 50 000 km 2 ). Restricted-range species are thought to face a greater risk of extinction than more widespread species since local impacts could cause global loss. We searched for information on status in the wild and characteristics of 397 restricted-range reef fish species. Fish body size, habitat requirements and usefulness to people were compared with those of a taxonomically-matched sample of more widespread species. We found that on average species with restricted ranges were significantly smaller (mean total length 19.1 cm versus 24.4 cm), tended to have narrower habitat requirements and were less used by people. Greater habitat specificity will tend to increase extinction risk while, if real, more limited usefulness (equivalent to exploitation) may reduce risk. Fifty-eight percent of restricted-range species were considered common/abundant in the wild and 42% uncommon/rare. Population status and threats to 319 species for which data were available were assessed according to the categories and criteria of the IUCN red list of threatened animals. A number of species were found to be rare, were exploited and had highly restricted ranges overlapping areas where reef degradation is particularly severe, placing them at a high risk of extinction. Five species were listed as Critically Endangered, two of them possibly already extinct in the wild, one as Endangered and 172 as Vulnerable. A further 126 species fell into Lower Risk categories and 11 were considered Data Deficient. Given the intensity of impacts to reefs, the broad geographical areas affected and the large numbers of restricted-range species, global extinctions seem likely. Urgent management action is now crucial for the survival of several species of reef fishes.

Predicting IUCN Extinction Risk Categories for the World's Data Deficient Groupers (Teleostei: Epinephelidae)

“…Fishes capable of utilizing deep-reef habitats are considered to be at lower risk of local extinction than fishes confined to shallow habitats (Lindfield et al 2014). Third, species with large geographic range sizes are generally at less risk than those that occur in restricted ranges, as a broad distribution permits a large population size and/or a buffer against habitat loss, therefore, able to withstand local extirpation without risk of global extinction (Hawkins et al 2000). Fourth, species that form spawning aggregations are likely to be vulnerable to overfishing, as evidenced by the loss of aggregations of commercially important species in many locations due to unsustainable fishing (Sadovy de Mitcheson & Colin 2012).…”

‘Damsel in distress’‐ The tale of Miss Kerala, Puntius denisonii (Day), an endemic and endangered cyprinid of the Western Ghats biodiversity hotspot (South India)

“…Trends in declining populations were also observed at one study site (Chalipuzha), the details of which are discussed in the following section. It is known that endemic species that present very restricted distribution ranges and small populations are especially vulnerable to local extinctions (Hawkins et al, 2000). The low abundance, gregarious and aggregating nature, easy location of habitats and/or aggregating locations, together with an increasing market demand and popularity, make P. denisonii highly vulnerable to overfishing and possible endangerment.…”

Fundamentos ecológicos y biogeográficos de la rareza de la avifauna madrileña: Una propuesta de modificación del catálogo regional de especies amenazadas

“…Esto es, las preferencias de hábitat muy especializadas suelen asociarse con propensión a tener problemas de conservación (Hawkins et al, 2000;aunque ver Gage et al, 2004). Esto implica una menor oferta de espacio favorable para la especie en una región y, por tanto, mayor susceptibilidad a ser amenazadas en el caso de que las limitadas condiciones que favorecen su existencia cambien (Owens y Bennett 2000).…”

“…Si estas reducidas áreas de distribución están sujetas a impacto humano fuerte, entonces las poblaciones de esas especies pueden estar sometidas a amenaza (Manne et al 1999;Hawkins et al 2000;McKinney 2001;Gage et al 2004). Ahora bien, la rareza geográfica puede ser una mera consecuencia de patrones biogeográficos sin una clara vinculación con el grado de amenaza.…”