There is a strong scientific consensus that both our actions – which contribute to the exacerbation of climate change – and the effects of climate change itself will likely result in the extinction of numerous species. We are already seeing this beginning with a surge in extinctions and endangered species in the present day. Recently, a study by the University of Southampton found that if we continue with business as usual, the number of species affected could be double what has been estimated over the next century.

The current projections for species extinction consider extinction to occur on an “ecologically random” basis. This study, instead, considers the ecological strategies of mammalian and avian species, to see which species are likely to have strategies that will allow them to survive the effects of an extinction event such as climate change. 

The study found that, while there are about twice as many birds as there are mammals, the diversity of ecological strategies is about a third less with birds than that of mammals. In other words, mammals have a greater array of species with different strategies, some of which may be successful in the face of potential external threats. On the other hand, the study determined that birds, as an overall group, have many of their ecological strategies in one basket, decreasing their chance of having a strategy that will allow them to survive in the face of potential threats like climate change. 

Interestingly enough, the study determined that the most optimal ecological strategy of the future is likely to be a species that is smaller, more fecund (has more sex, and produces more babies), has a shorter lifespan, is more generalist, and is more invertivorous (eats invertebrates). Highlighting this, data shows that mammals have generally reduced their size by 14% since the last extinction event, and the study predicts a further reduction in size, 25%, over the next century.

The study goes further to note that, when species that do not have the optimal ecological strategy for survival become extinct, there are further unintended consequences to ecosystems. For instance, vultures are the only vertebrate scavenger currently on record, and they face monumental challenges to survival. Not only are they an endangered species that is threatened by our actions to their environment, but they are also quite the opposite of the species of the next century referred to earlier. They are a large, less fecund, long lifespan, specialist, vertebrate species, but they also scavenge on a plethora of prey that carry disease. If vultures become extinct, all species within their ecosystem face the consequences of diseases run amok. 

The authors of the study point to the promise of conservation efforts such as habitat restoration and population management, and a need to prioritize these efforts in order to prevent an exacerbation of extinct species. We have not yet seen the breadth of unintended consequences from extinct and endangered species. Therefore, it seems to be in our best interest to invest in conservation efforts in order to prevent us from finding out what further consequences there could be.