|
||||||||||||||||||
|
|
|||||||||||||||||
|
Mediterranean HabitatsMediterranean habitats represent just 2.2 percent of the Earth’s land, but contain 20 percent of all known vascular plant species, packed into five narrow swaths of coastline:
Go DeeperGlobal Mediterranean Action Network Mediterranean Habitats: Lovely, Rare — and Endangered Mediterranean Habitats: FAQ Saving Mediterranean Habitats Worldwide Minding the Gap
Subscribe to Nature Conservancy Magazine |
By Danielle S. Furlich
Each day, motorists on U.S. Highway 101 near San Jose, California, speed unknowingly past some of the rarest and most imperiled habitats on the planet. But don’t accuse the drivers of haste or ignorance. Until recently, even the world’s ecological experts didn’t fully appreciate just how globally imperiled such lands are.
For only a few short months during winter rains do the native grasslands and oak woodlands that wrap around Mount Hamilton in the central Diablo Range look like the globally significant habitats they are. A chorus of greenery and wildflowers erupts on the hillsides. Then May arrives, and with it the famous California sunshine: six months of blue skies and no rain. The hills turn to gold again.
“Think what [the plants] have to adapt to,” says Lisa Van Cleef, a Nature Conservancy spokesperson and a 10-year volunteer at San Francisco’s Botanical Garden. “For six months you get rain, then it just stops. It’s basically a desert here for six months. The pendulum swings so rapidly.”
Hardship like that breeds plants and animals that can survive the stress. And just east of San Jose, the 700,000-acre Mount Hamilton range, wedged between Highway 101 and Interstate 5, harbors myriad such species. Here, tule elk, mountain lions and San Joaquin kit foxes roam across miles of open rangeland, gently sloped foothills, wetlands and rare oak woodlands.
Knowing that the Mount Hamilton landscape represents some of the last of “Old California” and its iconic ranchlands, state residents celebrated in January 2008 when the Conservancy announced that the Hewlett and Packard families had donated a conservation easement on their 28,359-acre San Felipe Ranch. Almost the size of San Francisco, the ranch sits like a puzzle piece between two county parks and a state park in the heart of the Mount Hamilton area. Its protection filled in the missing link in a corridor of protected lands that stretches 70 miles, from Pacheco Pass to Livermore Valley.
Rebecca Shaw, who directs the Conservancy’s conservation programs in the state, declared the easement a huge victory — for the entire world.
“The San Felipe Ranch harbors some of the most-biodiverse, most-threatened and least-protected habitat on the planet,” she told reporters. In other words, it has some of those rarest of rarities: intact Mediterranean habitats.
Overlooked and Underappreciated
Ultimately, it took scores of scientists and massive sets of biological data to uncover just how at-risk Mediterranean habitats like the San Felipe Ranch are.
Characterized by arid grasslands, shrublands and woodlands, Mediterranean habitats get their name from the largest of the five regions that harbor them — the basin surrounding the Mediterranean Sea. The other regions—coastal California and northern Baja California, southern Australia, the western cape of South Africa, and central and northern Chile — are the only other places on Earth that have a similar climate and vegetation.
All share the classic Mediterranean climate of mild, wet winters and hot, dry summers. These habitats harbor a full 20 percent of all known vascular plant species — so-called higher plants, with roots, stems and leaves — yet they take up just 2.2 percent of Earth’s land surface.
“Mediterranean habitats cover about 800 million acres,” says Robin Cox, a vegetation ecologist and associate director of conservation science for the Conservancy in California, “Which is nothing in the global scheme. They are tiny, tiny compared to other major habitat types.”
These places share another characteristic: People love them. Mediterranean habitats have blissfully sunny weather. They tend to have fertile soils suited to ranching and farming. Indeed, most of the world’s premier wine-producing regions occur here. Olives, citrus, avocados — all thrive on the warm slopes of Mediterranean habitats.
Experts from opposite sides of the globe cite similar pervasive threats that face these regions: expanding agriculture, increasing urban development, unsustainable tourism development and invasive species, including many that were imported from other Mediterranean regions.
The human impact on Mediterranean regions became clear in 2005, when scientists from the Conservancy and WWF published a study in the journal Ecology Letters revealing that Mediterranean habitats were significantly more imperiled than almost any other major type of terrestrial habitat — including tropical rainforests (see “Minding the Gap,” Nature Conservancy, winter 2006).
When researchers compared the amount of land converted to farmland, cities and the like against the amount of land protected, they found the ratio in Mediterranean habitats worldwide was 8 to 1. For every eight acres lost, only one has been protected. For tropical rainforests, the ratio is 2 to 1.
Put another way, approximately 40 percent of Mediterranean habitats have already been converted to human uses. About 5 percent have been protected in their natural state.
Since 2006, Cox and other Conservancy scientists have analyzed detailed information from each of the five Mediterranean regions. Their resulting maps reveal that things might be even worse than they seem: The existing protected lands in Mediterranean regions tend to miss the most biologically significant places.
“What tends to be set aside are the remote, steep, leftover lands,” says Cox. More useful — and species-rich—lands, such as wooded foothills and lowland areas, tend to be converted to agriculture, homes and other uses. Places like San Felipe Ranch, with its gently sloped woodlands and undeveloped valleys, are rare treasures indeed.
The Race is On
The Conservancy and its partners are now rallying to conserve 10 percent of intact Mediterranean habitats before it’s too late — an ambitious goal, given the many threats these areas face.
Yet the small size of the habitats overall and their commonalities may give conservationists an edge, says ecologist Jeff Parrish, director of the Conservancy’s new Global Mediterranean Habitat Conservation Program. Parrish and his team are helping Conservancy priority projects in Australia, Chile, California and Baja California protect key natural areas and slow the conversion of others. Central to that effort is connecting people in each of these places, while helping them learn from and collaborate with partners in South Africa and the Mediterranean Basin.
“No one else has approached the entirety of Mediterranean habitats as a global priority,” says Parrish. “The Conservancy has an opportunity to tap the collective smarts of everyone and design strategies to combat threats in all five regions.
“The other thing we can do is to raise awareness. So many millions find [Mediterranean habitats] to be desirable places to live, vacation or conduct business, but very few see the value of these arid lands as natural habitat. In the end, conservation is 1 percent science and 99 percent people. If society understands the need for conservation, and if we connect the champions working to conserve these habitats around the world, we can get the job done.”
California and Baja California | Australia | Mediterranean Basin | South Africa | Chile
Mediterranean Habitats: Lovely, Rare — and Endangered »
Nature picture credits: Photo © Ian Shive (Miniature lupine); Map © XNR Productions; Photo © Ian Shive (Mt. Hamilton, California); Photo © David Noton/naturepl.com (Tuscany, Italy)
Join The Nature Conservancy on