Research press release


Scientific Reports

Conservation: Feral cats pushing critically endangered marsupial further towards extinction

マウスほどの大きさの小型有袋類のエートケン・スミントプシス(Sminthopsis aitkeni)は、絶滅寸前種とされ、南オーストラリア沖のカンガルー島でしか見られない。今回、エートケン・スミントプシスが野良猫による捕食によって絶滅の危機に瀕していることを明らかにした論文が、Scientific Reports に掲載される。この論文では、特に林野火災などの自然災害の後に、脆弱な生物種を野良猫の捕食から保護することが緊急に必要なことが強調されている。


今回、Louis Lignereuxは、カンガルー島の特別に指定された保護区で2020年2〜8月に捕獲された86匹の野良猫の胃内容物と消化管を調べ、野良猫による捕食の影響を調べた。全ての野良猫は、オーストラリアの野良猫駆除プログラムの一環として捕獲され、南オーストラリア州の動物福祉法に従って安楽死させられた。Lignereuxたちは、野良猫7個体(サンプル総数の8.1%)の消化器系から8匹のエートケン・スミントプシスの遺骸を発見した。


Predation by feral cats is putting the critically endangered Kangaroo Island dunnart – a small, mouse-sized marsupial found only on the Kangaroo Island off South Australia – to the brink of extinction. The study, published in Scientific Reports, highlights the urgent need to protect vulnerable species from feral cat predation, particularly following natural disasters such as bushfires.

There are estimated to be only around 500 Kangaroo Island dunnarts (Sminthopsis aitkeni) left on Kangaroo Island, which is located off the South Australia coast. The island suffered significant damage during the 2019-20 bushfires and 98% of the dunnart’s habitat was severely burnt. Feral cat predation poses a significant risk to many native Australian species, but it has not yet been confirmed whether cats are a threat to Kangaroo Island dunnarts.

Louis Lignereux and colleagues investigated the impact of feral cat predation on Kangaroo Island dunnarts by assessing the stomach contents and digestive tracts of 86 feral cats that were captured between February and August 2020 in specially designated conservation areas on the island. All cats were captured as part of the national feral cat control programme, and were euthanised in accordance with South Australia animal welfare laws. The authors identified the remains of eight individual Kangaroo Island dunnarts in the digestive systems of seven different cats (8.1% of sampled cats).

These findings represent the first confirmation that feral cats do prey on Kangaroo Island dunnarts, and suggests they are efficient hunters of this species given the small numbers of dunnarts that remain following the bushfires. The combined pressures of a small, isolated population, natural disasters like bushfires, and predation from introduced predators such as feral cats could lead to the extinction of this vulnerable species, according to the authors. They highlight the need to maintain control of feral cat populations in areas home to threatened species.

doi: 10.1038/s41598-022-11383-6


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