Great Britain's ecosystems have become less resilient to the effects of environmental change over the past 40 years, finds a study in Nature Communications. This suggests that these ecosystems could be in danger of losing key functions that can only be performed by certain groups of species.
Different species within an ecosystem may play vital roles in ensuring that specific key functions are performed - for example, insects pollinating flowers or earthworms decomposing organic matter. Several species may overlap in their ability to provide these different functions, thereby providing some degree of insurance, or redundancy, in the ecosystem, should one of the other species be lost.
Tom Oliver and colleagues analyse trends in the abundance of more than 4,400 species of birds, mammals, invertebrates and plants in Great Britain over the past 40 years, and identify which ecosystem functions are being performed by each species. They find that there have been significant declines in the groups of species able to perform key functions such as pollination and pest control, whereas the groups that perform tasks related to carbon sequestration (such as vascular plants) and decomposition have been more stable over time.
By separating out which species within these groups were already present in Great Britain before 1970 from those that have arrived since then, the authors discover that the new arrivals have mostly been composed of species fulfilling functions such as carbon sequestration and decomposition, allowing these roles to remain stable over time. In contrast, fewer pollinator and pest control species have arrived into Great Britain during this time interval, suggesting that species vital to agriculture and food production may be less resilient to environmental change, and are being eroded rapidly.