Biodiversity crucial for ecosystems

'Happy families' formed when complementary species grow together


Wildlife variety is the spice of life — we know it, and now scientists have confirmed it. Biodiversity is crucial for ecosystems to work properly, according to a French-British study published in Nature this week.

Conservation groups have long campaigned to preserve the environment, arguing that we have a moral and ethical responsibility to protect other living things.

But without having a hard scientific argument for conservation, their efforts have often fallen on deaf political ears. Now the results of a massive, three-year ecological experiment show that the specialization of different plant species to different roles fundamentally affects the way that ecosystems work.

Andy Hector of Imperial College in London, a coauthor of the report, said, “There is now another reason to preserve diversity — it plays a critical role in determining the way the environment works.”

Hector and Michel Loreau of the Ecole Normale Superieure in Paris analyzed the results of harvests from experimental grasslands at eight sites across Europe, from Sweden to Greece. The “mini-meadows” varied in plant diversity to mimic the gradual loss of species seen throughout Europe.

The results show that plants grow better when they consist of teams of species that are complementary to one another. Moreover, harvest yields were higher when a range of plant species was grown together.

In the real world, this could mean that the amount of sunlight converted into plant life — the “productivity” of an ecosystem — also declines when species are missing. Lose enough species and, like losing rivets from an airplane, eventually the whole thing falls apart.

Conservationists have thus received a powerful new economic and scientific argument for preserving biodiversity.