On May 1, a study published in the journal Science concluded that “extinction rates will accelerate with future global temperatures, threatening up to one in six species under current policies.” The solution proposed by the author is one that has been heard lately too many times to ignore: Limit climate change or more species will become extinct.
Given a temperature increase of three degrees Celsius, the extinction rate rises to 8.5 per cent, while a 4.3 degrees temperature increase will bring the percentage to 16, which means that one in six species could disappear.
The repercussions of any species disappearing is more complex than just switching it to a different list. Nothing exists on its own, and the ecosystem functions as a complex symbiotic machine where every species contributes to life as we know it.
The regions most threatened, the study points out, are South America, Australia and New Zealand, and the least threatened Europe and North America. Species most at risk, according to the same study, are reptiles and amphibians. It is not the first time these species, yet another example of unlikely canaries, have been mentioned by researchers in an effort to bring the extinction subject to the general public.
For anyone doubting that the situation is indeed becoming dire, there is more evidence to support the same scenario, only from a different angle and featuring the disappearance of much larger species whose role in their natural habitat is inestimable.
In a report published Friday in the journal Science Advances, scientists report that many species are disappearing (as much as 60 percent of certain species) and it is humans who are causing it.
Large herbivorous species such as hippos, rhinoceros, gorillas and elephants, are severely threatened by excessive hunting, poaching, loss of habitat due to deforestation, high density of livestock and climate change.
The big issue, the study emphasized, is that when these big animals go, they’ll initiate a cascade of unwanted events that will affect other species and the very habitats they occupy.
Big herbivores do more than just eat vegetation, the study explains. Their role is as complex as can be: they spread seeds, interact with smaller species, shape the distribution of wildfires across a landscape and the distribution of various species of plants throughout entire areas. Also, by constantly eating and defecating large amounts of plant biomass, they provide a unique nutrient cycling process that cannot be performed by small herbivores.
Big predators and scavengers who depend on them, many of whom are already threatened by overhunting and habitat loss, will see their numbers decline due to loss of their primary source of food.
The most important factor in the decline of the largest terrestrial herbivores was revealed to be, surprisingly enough, excessive hunting, more so than human encroachment and habitat loss. Animals in protected areas are no longer safe, the study points out, as most of these areas suffer from a reduced management budget to begin with.
It is estimated that approximately one billion of people rely on wild meat as their source of protein. With large herbivores disappearing at alarming rates, people in the affected areas will not only suffer the direct consequences of extinction as their food supplies will dwindle, but they will also lose the economic boom brought by ecotourism.
The authors urge for many issues to be addressed and soon. Among them, directed research that will shed more light into the ecology of various herbivores in South-East Asia, Africa and South America, lowering human birth rates in rapidly growing regions where large herbivores are threatened, focusing conservation efforts and addressing poaching all the way to those who demand it, managing protected areas as well as areas with high density of livestock, and last but not least, addressing climate change.
It is a tall and complex order, yet compared to what we all stand to lose should the present trend continue, it is more than worth the cost.