The scientists found that some species are more critical than others in preserving the functions of ecosystems and that these species tend to be those that are genetically unique. Therefore, they are looking to evolutionary history for guidance in conservation efforts and in understanding the potential impacts of species loss.
Recent studies show that ecological systems with fewer species generally produce less biomass than those with more species. Less plant biomass means that less carbon dioxide is absorbed from the atmosphere and less oxygen is produced. So, as the biomass of plants plummets around the globe, the composition of gasses in the atmosphere that support life could be profoundly affected. Additionally, there are fewer plants for herbivorous animals to eat. Entire food chains can be disrupted, which can impact the production of crops and fisheries.
The loss of species that are not closely related to other species in the ecosystem reduces productivity more than the loss of species with close relatives. And the more genetically distinct a species is, the more impact it has on the amount of biomass in an ecosystem.
"Losing a very unique species may be worse than losing one with a close relative in the community," said Oakley. "The more evolutionary history that is represented in a plant community, the more productive it is."
Cadotte explained that the buttercup is a very unique species, evolutionarily. Losing the buttercup, where it occurs in grasslands, would have a much bigger impact on the system than losing a daisy or a sunflower, for example. The latter species are closely related. Each could therefore help fill the niche of the other, if one were to be lost. The daisy and sunflower also have a more similar genetic make-up.
"These 40 studies are showing the same thing for all p
|Contact: Gail Gallessich|
University of California - Santa Barbara