O’ahu is a Hawaiian island that has been studied for its unique insight into the future of ecosystems on Earth. Due to the remote location of Hawaii, existing about 3200 km from its closest neighbour, native species evolved with very little influence or interference from the outside world. This led to the evolution of unique species not found anywhere else in the world, such as the moa-nalo, a 2ft tall, flightless bird.
However, the arrival of humans caused change for the ecosystems. Forests were cleared and new, non-native species were introduced, many in the last century or two. This includes various plants, dogs, rats, and even mosquitos that spread avian malaria. Of the 142 native bird species found uniquely on Hawaii, only 47 now remain. The lowland forests of O’ahu are nearly completely missing the plants and animals that evolved there, and are instead a collection of non-native species from around the world.
Despite all these species being thrown together, they have developed a level of organization typically present in stable ecosystems that have evolved together for millennia. This is referred to as a novel ecosystem, or a “freakosystem” as named by Eric Higgs’ daughter. Higgs is a professor of ecology at Canada’s University of Victoria. In this BBC article, he says that the hallmark of a novel ecosystem is “practical unrestorability”, or the idea that it is impossible to return the ecosystem to its pre-human state. These ecosystems are a direct result of human influence, but have then grown to become self-sustaining and do not rely on human management. Many of the non-native species have become deeply integrated into the ecosystems, with some even evolving traits to better fit the area that they invaded.
Novel ecosystems have forced ecologists and conservationists to reevaluate strategies for preserving native species and restoring ecosystems.These systems have been found around the world, and the non-native species in them are often found to play important roles in the functioning of the system. On O’ahu, non-native birds help spread the seeds of native plants as well as non-native ones. In Australia, introduced species have actually made drylands more similar to what they were like in the past, and in the Sonoran Desert, feral donkeys dig water holes that support over 50 other species.
As with many things in nature, there is no hard line we can draw to identify novel ecosystems, and there is no clear method for appropriate conservation. Since these systems are not going anywhere, continued research is needed to determine what the best action plan is for protecting the adapting natural world.