How Biodiversity Keeps Earth Alive

[xchrom]

http://www.scientificamerican.com/article.cfm?id=how-biodiversity-keeps-earth-alive


BIODIVERSITY: Native wildflowers add diversity to this prairie-like California grassland.
Image: © David Hooper

In 1994 biologists seeded patches of grassland in Cedar Creek, Minn. Some plots got as many as 16 species of grasses and other plants—and some as few as one. In the first few years plots with eight or more species fared about as well as those with fewer species, suggesting that a complex mix of species—what is known as biodiversity—didn't affect the amount of a plot's leaf, blade, stem and root (or biomass, as scientists call it). But when measured over a longer span—more than a decade—those plots with the most species produced the greatest abundance of plant life.

"Different species differ in how, when and where they acquire water, nutrients and carbon, and maintain them in the ecosystem. Thus, when many species grow together, they have a wider set of traits that allow them to gain the resources needed," explains ecologist Peter Reich of the University of Minnesota, who led this research to be published in Science on May 4. This result suggests "no level of diversity loss can occur without adverse effects on ecosystem functioning." That is the reverse of what numerous studies had previously found, largely because those studies only looked at short-term outcomes.

The planet as a whole is on the cusp of what some researchers have termed the sixth mass extinction event in the planet's history: the wiping out of plants, animals and all other forms of life due to human activity. The global impact of such biodiversity loss is detailed in a meta-analysis led by biologist David Hooper of Western Washington University. His team examined 192 studies that looked at species richness and its effect on ecosystems. "The primary drivers of biodiversity loss are, in rough order of impact to date: habitat loss, overharvesting, invasive species, pollution and climate change," Hooper explains. Perhaps unsurprisingly, "biodiversity loss in the 21st century could rank among the major drivers of ecosystem change," Hooper and his colleagues wrote in Nature on May 3. (Scientific American is part of Nature Publishing Group.)

[Botany]

1. Thanx for posting!

n/t

[tabatha]

3. Thank you.

I have encountered spots where a variety of wildflowers grow - some flowering and seeding before others start, and many at the same time.