Great whites and whale sharks are among the species at risk of extinction over the next century, a new study has found.
Pimiento is the lead author of a study published in Science Advances that looks at how the extinction of large marine species would impact the ecological roles of ocean ecosystems. "The extinction crisis challenges scientists to better measure biodiversity: how will the total variety of life on Earth be affected as human activities lead to the losses of more and more species?" they said. In the oceans, the biggest animals are thought to play crucial ecological roles, and are also facing high levels of threat from human activities such as fisheries and climate change.
The team was looking to move beyond traditional species extinctions, to find out more about the functional diversity, the range of roles that these species perform, and how biodiversity might respond under different extinction scenarios (预测). They ran two different extinction scenarios. In one, researchers looked at extinction probability based on their current IUCN (International Union for Conservation of Nature) status. In the second, they assumed all species listed as threatened, around 40 percent, had gone extinct.
Sharks were found to be one of the worst affected groups. "We already knew that sharks are one of the most threatened groups in the ocean," they said. "They are also very vulnerable due to their large size and low reproductive rate. Our results show that future extinctions would be selective against the most functionally unique and specialized shark species, resulting in greater projected losses." They also said the biggest threats to marine megafauna （大型哺乳动物群） are fishing, either through accidentally getting caught up or directly targeted, and climate change. Mitigating these threats could be the best way to protect these species.
The good news is that the study identifies key species that can be targeted and protected. Sometimes ocean conservation can be a triage game. The science helps us know which species really need our help and which species we really cannot afford to lose.
