Biodiversity helps sustain human life, scientists say
New report in the journal Nature attempts to measure the impact biodiversity has on human health and well-being.
WASHINGTON — Experts worldwide have long talked about the importance of preserving the diversity of life for the sake of beauty and wonder, or in the hopes of new medical discoveries, or for moral reasons.
A group of scientists is reporting that biodiversity also helps sustain human life.
"There are direct measurable impacts on human prosperity and human well-being," said Bradley Cardinale of the University of Michigan, lead author of a team of 17 ecologists who reviewed hundreds of experiments done in the past 20 years. "That places conservation in a whole other ballpark."
The report cited a number of ways in which biodiversity — the variety of species, genes and traits — has practical value.
For example, genetic diversity within a species can increase the yield of commercial crops. Diversity of tree species increases production on timber plantations. More fish species means more stable yields for fishermen.
Diversity in the types of plants that grow together also can make the plants more resistant to disease and invasive species, and in some cases make them pull more carbon dioxide out of the atmosphere.
The first Earth Summit, in Rio de Janeiro, Brazil, in 1992, warned that human actions were destroying habitats and reducing biodiversity at an alarming rate. New evidence has shown that biodiversity loss is continuing, often at increasing rates, the report said. At this pace, scientists estimate that one-third to one-half of all species could be lost permanently in about 100 years.
Cardinale said the report was meant as a warning. The journal Nature published it this week in advance of an international conference on sustainable development, known as Rio+20, this month.
"The rate of extinction for organisms we've been able to document is about 1,000 times faster than what occurs in the fossil record," Cardinale said.
"Our paper is basically saying, 'Look, if those hundreds of thousands of species go extinct, you're going to feel it in your pocketbook. It's going to affect food production, it's going to affect climate — all those things we care about,' " he said. "And there's overwhelming scientific evidence to support it."
David Hooper of Western Washington University, another one of the authors, said he hoped it would influence world leaders.
"Where I live, around Puget Sound in Washington state, it's one of the most beautiful areas in the world — and, in fact, that natural beauty is a source of local pride, tourism dollars, and natural resources, such as clean water and fisheries. Even so, we have at least 25 species threatened with extinction, ranging from small wildflowers to chinook salmon and Orca whales," Hooper wrote in an email.
Many other species are declining as a result of habitat loss, overharvesting and environmental degradation caused by humans, he added. "While some of those species might disappear with barely a whisper, others are hugely important ecologically, economically and culturally."