“I tell my students, you’ve got to make
lemonade out of the lemons,” Stachowicz
says. Hughes kept monitoring the disaster zone. Eelgrass plots with more genetic
diversity tended to regrow to their former density faster, she and Stachowicz
reported in Proceedings of the National
Academy of Sciences in 2004.
But biodiversity doesn’t always show
a short-term effect. For eelgrass growing in the wild, only one of the two characteristics that Hughes and Stachowicz
measured, shoot density, correlated with
genetic diversity, and only in the winter.
That’s the time for goose attacks and
other miseries, so maybe that’s when
bounce-back power really matters,
Stachowicz and Hughes, now of Florida State University Coastal & Marine
Laboratory in St. Teresa, speculated in
May 2009 in Ecology. Likewise, biodiversity effects showed up in the long
run but not the short-term in work on
algal-species mixes, Stachowicz and colleagues reported in Ecology in 2008.
Regardless of the technical ecology
research, Miller says, preserving biodiversity is just common sense. He makes
what’s been called the “intelligent tinkerer” argument: When fiddling with
something complicated and not entirely
understood, it’s not smart to throw away
parts — especially when those systems
keep humanity alive on the planet. Miller
hands over a printout of a list he’s made
of some services: clean water, wild fish,
pollinators for crops, protection from
erosion, clean air…. Pulling pieces out of
ecosystems puts these services at risk.
Also, he points out, biodiversity has
aesthetic and spiritual values. Stewardship of the natural world stands as an
obligation of certain religious traditions.
And some deep urge in humankind, what
entomologist Edward O. Wilson of Harvard University has called “biophilia,”
may draw people to other living things.
Back among the insects, Miller pulls
out a drawer with row after row of ranks
of iridescent blue Morpho butterflies to
illustrate his point. Most people have at
one time or another admired portraits
of these beauties, but such images don’t
do justice even to museum specimens,
maintaining biodiversity by protecting wild or lightly inhabited land alone would
overlook the realities of this crowded century, says mark goddard of the Univer-
sity of leeds in england. Humankind’s footprints already cover a lot of space.
in 2008, for the first time, more than half the planet’s people lived in cities.
so bits of greenery in yards or urban parks need attention, goddard and his col-
leagues argue in the february Trends in Ecology and Evolution. surveys show that
remnants of nature in built-up environments can boast impressive populations of
some species. bumblebees of several kinds proved more abundant in san fran-
cisco’s urban parks than in two parks outside the city. in britain, the density of
one bumblebee species’s nests in suburban yards matched the density in hedge-
rows in the countryside. and the frog Rana temporaria declined in the english
countryside but thrived in towns. if biodiversity can be promoted in a city’s crazy
quilt of greenery, the areas could add up, goddard says.
conservationists are already experimenting with incentives, pledges and certi-
fication programs to coax private landowners to make the most of their yards. in
the United kingdom, the royal society for
the protection of birds has inspired more
than 25,000 people to improve their habi-
tats through the Homes for Wildlife plan.
and in the United states, the national
Wildlife federation’s certified Wildlife
Habitat program has reached more than
100,000 properties. yards and urban
parks do present harsh challenges, such
as bird-unfriendly cats. but early research
has started sorting out what factors might soften urbanization’s impacts.
even the most artificial of landscapes might be rendered at least a little friend-
lier to biodiversity, say two forest ecologists at the University of Quebec city in
montreal. tree plantations, usually created as rows of a single species destined
for harvest for timber or pulp, “have a bad reputation,” alain paquette says. in
the february Frontiers in Ecology and the Environment, he and christian messier
argue that plantations need not become biodiversity deserts. foresters might
leave patches of previous stands for animal habitat as the next stand grows,
or tighten up soil preparation to reduce erosion. one hefty change would be to
trade monocultures for polyculture plantations growing several tree species.
foresters have resisted the mix, in part because harvesting gets complicated. but paquette and messier report that planting fast-growing hybrid
poplar as nursemaid species to shelter slower-growing trees shows promising
early results. last year the researchers set out young trees in test plots of up
to a dozen species to find out what kinds grow well together. paquette says he
hopes that experiments that have predicted higher biomass in the presence
of greater species diversity will apply to practical forestry, too. — Susan Milius
which shimmer and glow as the angle
of view tilts. Next, Miller displays some-
thing less familiar: a drawer of adult
Heliodinidae moths, which are bigger
than rice grains but not by much. Bend-
ing close, he points out blazes of russets
and rich browns mixed with white on tiny
but lovely wings. There’s inspiration in
known diversity and in the variety that
has yet to be admired. And that is indeed
something to celebrate. s
iUcn: www.iucnredlist.org s
millennium ecosystem assessment: s
march 13, 2010 | SCIENCE NEWS | 25