Biodiversity Mini-Reviews
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Biodiversity
If put to a vote, most people would probably choose to protect biodiversity, although few of them could explain exactly what it is they hope to protect. The term biodiversity has been used so often, and so loosely, that it's meaning has become obscured. On the simplest level, it relates to the dizzying array of life forms, filling every conceivable niche on scales ranging from microbes to blue whales. Variety is not only the spice of life but the essence of life itself.This variety assumes many forms. First, there is the vast profusion of animal, plant and microbial species, roughly 1.4 million of which have been cataloged to date. Current estimates suggest the Earth may house at least 10 times that many species. At any given moment, there are roughly 100 trillion insects alive on this planet, mostly creatures yet to be identified. The fact is, no one can make a truly educated guess as to the total number of species, which shows how little we know about our biological heritage. In addition to the new species to be found, there are likely to be entirely new kingdoms of life yet to be discovered.
But biodiversity is more than just an immense, though untold, number of species. Perhaps equally important are the genetic variations within species– a product of evolution that allows populations to cope with changing environmental conditions. When populations drop below a critical threshold– owing to human encroachment, among other factors– a species may become so uniform it cannot adapt and survive.
On a grander scale, biodiversity is manifested in the different kinds of ecosystems– from wetland to desert, Arctic tundra to tropical rainforest and Alpine meadow to coral reef– where various species interact to form the working units of nature that sustain life every where.
Researchers trying to chart biodiversity are fighting the clock, with species disappearing at what may be an unprecedented clip– often slipping from our grasp before we have the chance to study them. Many experts believe the sixth major extinction in our planet's history is underway, this one with the distinction of being largely caused by humans. By some accounts, we're losing species 10,000 times faster than new ones are being generated through evolution. The threats come from many sources, including climate change, industrial and agricultural pollution, destructive hunting and fishing practices, deforestation and other activities leading to habitat fragmentation and destruction. Regardless of the exact causes, the net effect is the erosion of our natural legacy– a loss that is incalculable and, in many cases, irreversible.
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Ecosystem Resilience
Celebrated species such as the Northern right whale and spotted owl are hovering on the brink of extinction, but far more is at stake. The health of ecosystems themselves is in jeopardy, as a broad range of species– each having a sufficiently large population– is needed to maintain the critical services these natural realms provide. Research has shown, moreover, that biologically diverse systems are more productive, stable and resilient in the face of environmental change. That's important since change is, oddly enough, perhaps the one constant in nature: Animal populations in the wild invariably fluctuate, floodwaters rise and recede, tides ebb and flow, winds howl and subside, glaciers advance and retreat. Ecosystems endowed with an abundance of species have built-in buffers that help them absorb unexpected shocks.
"In some ways, an ecosystem behaves like a stock portfolio," explains David Tilman, a University of Minnesota ecologist who has studied several hundred experimental grassland plots exposed to insect outbreaks, drought, shifts in temperature and precipitation, and other climate variations. "A large portfolio is more diverse than a single stock and less volatile through time." Credible attempts to shore up the resilience of ecosystems must involve, if not focus on, preserving their biodiversity.
Resilience stems not only from having a wide range of species that perform different services, but also from having a number of different species that perform similar functions. In grasslands, for instance, one species might bear up well under drought, another might tolerate cold, a third might be fire resistant, and so forth. Having distinct, but functionally equivalent species that can substitute for each other provides the capacity to respond to a variety of environmental stresses.
Resilience is also generated by the presence of species that can respond to disturbances on different spatial and temporal scales– ranging from centimeters to thousands of kilometers and from hours to millennia. The periodic infestation of fir trees in Canada by the spruce budworm offers an example. At least 31 bird species prey upon the budworm, an adept defoliator that can wipe out large areas of forest. When budworms are scarce, only small birds feed on them. As the outbreak grows, larger birds move in over greater distances, introducing a powerful regulatory check. This kind of protective mechanism only works in large forested regions, rather than in small, isolated preserves, because budworm predators need ready access to the infested areas. Breaking up ecosystems into ever smaller parcels, a common practice today, can lead to the disappearance of species, thereby reducing both biodiversity and resilience.
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Taking Stock
When it comes to biodiversity, our ignorance is staggering, given how much we depend on the innumerable organisms that make our world something more than a barren rock. So far, we've probably identified fewer than a tenth of the creatures on Earth, yet our country presently spends far more searching for life on other planets than on our own.
The All Species Project, an initiative started by 40 scientists in 2000, hopes to fill this knowledge gap. The goal is to create a list of every living species, including microbes, within 25 years. Fund-raising is already underway for this effort, which is expected to cost at least $20 billion. The proposition is, of course, absurdly ambitious. Countless numbers of unknown species are concealed from view in a biosphere whose full extent has never been mapped out. Assembling a comprehensive database will also be hampered by a shortage of skilled researchers and a maze of political and legal issues. Nevertheless, the idea of counting all the world's species by a specific deadline sets an inspiring target that could yield dividends even if outright success is unrealistic. To the extent that biodiversity is viewed as the totality of life forms on this planet, our conception of it will expand with every new discovery.
Of course, it's not enough simply to inventory as many different organisms as possible. We need to safeguard biodiversity, not just count species before they go extinct. Since habitat loss and fragmentation are the principal causes of species extinction, the best way to save biodiversity is to save natural habitats wherever possible. Yet many ecologists consider the $6 billion annually spent on the world's wildlife reserves an inadequate sum, given that ecosystems sustained by biodiversity provide tens of trillions of dollars worth of essential services each year, according to a 1997 analysis published in Nature. Viewed in this light, spending a few extra billion to support biodiversity would be a wise investment.
An international team of conservationists recently estimated it would cost $30 billion per year to establish an international reserve network covering 15 percent of each continent, thereby providing a more substantial cushion for global biodiversity. That's not a trivial sum, yet it is certainly within the grasp of the world's richest nations. In fact, a few of the world's wealthiest individuals, if they were so inclined, could pool their resources and, for a number of years, pay the sum out of their own pockets.
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Hotspots
If it makes sense to cordon off a portion of our land from the forces of development and destruction, how do we decide which areas to set aside? The concept of biologically rich "hotspots," homes for creatures found nowhere else in the world, was devised for this reason– to suggest an optimal way of focusing our conservation efforts so that the most species can be saved per dollar invested. This strategy is necessary, argues a group of ecologists headed by Norman Myers at Oxford University, because the number of species threatened with extinction greatly exceeds the conservation resources available for protecting them.
The team has identified 25 hotspots that cover just 1.44 percent of the Earth's land surface– roughly the size of Alaska and Texas combined– while serving as the exclusive home to a disproportionate number of plant and animal species. About 60 percent of the world's terrestrial plants and animals are confined to these zones, which include 17 tropical forest regions. They are located on every continent except Antarctica, plus islands like Madagascar, the Philippines, New Zealand, New Caledonia and Hawaii.
The hotspots were selected because of exceptional concentrations of "endemic" species unique to the region and because of extreme habitat loss, with nearly 90 percent of their original vegetation gone. Due to this special combination of factors, hotspot advocates believe these areas deserve the "lion's share" of our attention over the next decade or two. About $400 million has been invested since 1989 to support the cause but much more money is needed, say Myers and his colleagues. An average of $20 million per hotspot per year over the next five years would "go far towards safeguarding the hotspots and thus a large proportion of all species at risk." (The total, $500 million per year, is exactly what NASA plans to spend this decade on missions aimed at finding out whether there is life on Mars.)
These steps cannot come soon enough, according to Stuart Pimm of Columbia University and Peter Raven of the Missouri Botanical Garden. For even if remaining habitats within the hotspots are quickly protected, 18 percent of their species will still go extinct, they claim. Without prompt action, species loss will be twice as high.
Preserving hotspots is just the beginning. Unless we also protect the large stretches of tropical forests that lie outside these designated areas, note Pimm and Raven, the resultant species loss should exceed that in the hotspots within a few decades.
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Madagascar
In the grand hierarchy of hotspots, Madagascar consistently rates among the "hottest of the hots." The world's fourth largest island, isolated from other land masses for more than 160 million years, Madagascar affords a rare window on evolution. Most of its plant and animal species evolved separately from the rest of the world's biota and are thus found nowhere else on Earth. It is a treasure trove of biodiversity– home to almost 10,000 unique plants, including the rosy periwinkle, the source of the anti-cancer drugs vincristine and vinblastine and dozens of other medicinal chemicals. More than half the known species of chameleons are native to Madagascar, as are a spectacular assortment of primitive primates and some of the largest earthworms seen anywhere.
But Madagascar is also one of the most threatened hotspots, with its plants and animals facing possible extinction due to slash-and-burn subsistence farming, rampant logging, illegal poaching, mining and other practices. More than 90 percent of the original primary vegetation is gone. Some of the island's most famous occupants are lemurs, its only non-human primates. While at least 49 lemur species roamed Madagascar a few thousand years ago, just 32 survive today, 23 of which are imperiled.
Environmentalists hoping to stem the devastation must confront the fact that Madagascar is one of the world's poorest countries, with an average per capita income of less than $250 per year. It's hard to worry about the health of the forest– or the fate of such rare creatures as the leaf-tailed gecko, red-ruffed lemur, and serpent eagle– when people are starving. To be effective, ecological strategies must offer some economic promise for a needy populace.
For example, lemur researcher Patricia Wright spent five years explaining the potential value of Ranomafana National Park to nearby families before the park was established a decade ago. Villagers now hold about 130 jobs in the park and receive half the entrance fees to the wilderness area, which is visited by 10,000 tourists each year. Owing to grants from the United States Agency for International Development and conservation groups, creation of the 108,000 acre rainforest preserve was accompanied by the construction of eight new schools, four health-care centers and rural libraries, as well as the renovation of 10 existing schools. Efforts like this have convinced conservationists that in poor nations, we can't just build a wall around biologically-rich regions and keep everyone out. Instead, people need to feel they have a stake in protecting the biodiversity around them.
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Life On The Edge
Rainforests cover just a tenth of the Earth's land surface yet provide a home for about half the known plant and animal species. Many of the hotspots identified to date contain tropical forests, not surprisingly, since hotspots are, by definition, species-rich regions. Although the greatest concentrations of life lie in the forest interior, recent studies have shown that the forest's edge or margin may be important for producing modifications within species, as well as spawning new species, that keep the forest's biodiversity pool from stagnating. In response, some biologists are now shifting their gaze from the rainforest core to "ecotones"– transition zones between environments that serve as breeding grounds for adaptive variations and new species.
Along the edge of the rainforest in Cameroon, Africa, for example, savanna species are continually adapting to forest environments and forest species are adapting to savanna (or grassland) environments. For the past 20 years, UCLA biologist Tom Smith has studied many species in the Cameroon ecotone, including the little greenbul, a common bird. Most ecotone-based greenbuls differ from their rainforest counterparts in both size and shape: They are heavier and have longer legs, longer wings, and deeper beaks– changes thought to confer advantages. The longer wings, for instance, make the birds better equipped to evade aerial predators in more open environments. In some cases, the morphological differences are bigger than those seen between different bird species living in the same habitat. Smith believes he and his colleagues are witnessing the early stages of species generation known as "speciation."
Bolstered by similar findings elsewhere in Africa, Australia and South America, the researchers argue that long neglected ecotones may warrant as much attention from conservationists as hotspots themselves. "We tend to ignore areas along the periphery, even though they might play a critical role in promoting biodiversity," Smith says. "If we're trying to conserve biodiversity, we need to conserve these transitional habitats as well."
Ecotones are being destroyed faster than rainforests because they are largely unprotected by law and are more accessible to humans. "Now we're seeing a sharp border rather than a large transition zone, as people build to the edge of the rainforest," Smith says. "That doesn't allow for the kind of adaptive processes we've observed." Protecting adaptive variation is crucial, he adds, because it allows populations to persist in the face of environmental change. "If we minimize variation as a result of losing transition zones, we might be in trouble from climate change since that's what shields populations from extinction."
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Going To Extremes
In addition to the 25 officially recognized hotspots, there are countless literal hotspots– scalding hot to be exact– that give rise to exotic life forms. Hydrothermal vents, geysers on the ocean floor first spotted in 1977, are host to complex ecosystems inhabited by red tube worms, giant clams and other strange creatures. Some investigators believe life on earth may have originated in these undersea cauldrons. At the earth's surface, microorganisms found in hot springs at Yellowstone National Park can thrive in boiling hot water. One microbe discovered in a Yellowstone spring produces an enzyme which is now used for polymerase chain reactions (PCR)– a gene-copying technique that is central to genetic research and engineering. Other enzymes identified at the park are used in laundry detergents and for removing paint from old airplanes.
While some researchers are exploring the extremes of hot, others are thinking cold– Antarctic cold. More than 70 lakes have been identified beneath the Antarctic ice sheet. The biggest of them, Lake Vostok, lies four kilometers below the surface, yet many biologists believe living creatures will be found there, once techniques are developed for sampling the lake without contaminating it. Strong evidence of microbial life has already been detected in what is thought to be refrozen lake water.
Caves hold an allure for other explorers who have uncovered hundreds of bacterial strains never seen before. For example, creatures that evolved in New Mexico's Lechuguilla Cave, the deepest cave in America, may have been isolated from other ecosystems for millions of years. Biologists have sampled pools in the cave just a hundred or so feet apart that contain almost completely different sets of organisms.
An obvious lesson to be drawn from this far-ranging research is that biology is much more tenacious and widespread than previously thought. It's clear that in our attempt to catalog life in its various guises, we've barely scratched the surface. A single gram of soil may hold 10,000 unidentified species. Whereas scientists once thought the habitable zone constituted a thin strip near the surface, new species of bacteria have since been found encased in rock nearly three kilometers underground.
The ocean sediments are similarly rich: One gram may contain a billion organisms, the vast majority of which have never been classified. A host of unknown microbial organisms has been found a kilometer below the sea floor. No one has determined the temperature and pressure thresholds beyond which life cannot survive. Researchers continue to dig deeper, probing the biosphere's borders, but no limits have yet been found.
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Search For Solutions
Given the complex array of threats to biodiversity, it is hard to imagine a single, or simple, solution to the problem. At a minimum, profound changes in patterns of consumption and development will be needed, requiring coordinated action among public and private institutions. As is the case with many environmental dilemmas, a common ground must be found between economic interests and the desire to safeguard nature.
Habitat preservation is considered the single most effective way of protecting species, and the costs need not be prohibitive. The Nature Conservancy, for example, purchased a stretch of Bolivian rainforest as big as Yellowstone National Park for just $1.5 million– the cost of a home in some U. S. neighborhoods. But money, alone, is not the answer. Local people have to embrace conservation initiatives– "community-based stewardship," as it's sometimes called– for such efforts to have a chance of success.
Two American ecologists, Dan Janzen and Winnie Hallwachs, raised $28 million to acquire more than 320,000 acres in Costa Rica that are now part of the Guanacaste Conservation Area, which is owned and managed by area residents. Forests are being restored on abandoned ranches and additional land is being sought, one parcel at a time, offering a hopeful model for how biodiversity might be saved throughout the world.
Of course, it's not enough to set aside land, call it a nature preserve, and leave it at that. People accustomed to using the resources of an area for generations won't automatically stop just because it's been designated a national park. Illegal cutting of timber had been widespread in a rainforest preserve established on the slopes of the Philippines' Mount Isarog until villagers enlisted as guards to prevent logging. Part of the motivation was to prevent landslides like the one that occurred a decade ago on a nearby mountain, killing 7,000 people. But the villagers have broader concerns now that they've become full partners with conservation groups in deciding how to manage the forest.
Education is an important component of such partnerships. In large forested "buffer zones" that surround the recently-established Masoala National Park in Madagascar, villagers are taught how to use the land in a sustainable manner, both for farming and tree-cutting. They're instructed, for instance, on how many trees can be safely cut and how many need to be planted in their stead to insure future harvests. As citizens gain proficiency in sustainable practices, they will be better equipped to protect one of their region's great treasures– biodiversity.
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Banking For The Future
Whenever possible, the first option for safeguarding biodiversity ought to be preventing the degradation of natural habitats. That's just common sense: Why mess with finely-tuned systems, honed by evolution over the course of millennia? Unfortunately, that approach is not an option in cases where ecosystem damage is too great. A backup strategy is to preserve endangered species through zoos, botanical gardens, and seed banks, with the hope of eventually reintroducing plants and animals to their former habitats. Given that animals are expensive to maintain, and often breed poorly in captivity, there is little prospect of saving thousands of endangered species in zoos. The largest seeds banks, which hold close to half a million samples, can save far greater numbers of species.
The Switzerland-based World Conservation Union has placed 34,000 plant species on its global list of imperiled organisms. The threats to plants are of concern for several reasons. On the most basic level, the world's biodiversity depends to a large extent on maintaining a broad range of plant species. As plants disappear from the land, a number of living organisms will be jeopardized too.
We have, of course, a more immediate interest in plants as food sources. Throughout history, about 10,000 plant species have been used in agriculture, but 120 species now account for 90 percent of the food supplied from plants. The increased reliance on comparatively few species, coupled with the steady loss of wild strains, leaves us vulnerable to widespread crop failure and famine. This was amply demonstrated in the 1840s when the potato blight ravaged Ireland's staple crop, causing two million people to starve and millions more to emigrate.
Preserving a genetic resource base enables plant breeders to boost resistance by infusing hardy genes, derived from wild strains, into commercial crops. That's the premise behind the National Seed Storage Laboratory in Fort Collins, Colorado, which contains about 450,000 seed samples, and a similar, though somewhat smaller, facility in Canada. The Kew's Millennium Seed Bank, established at Britain's Royal Botanic Gardens, hopes to obtain and store seeds from 10 percent of the world's flora by 2010. In addition to saving genetic diversity for food crops, part of the motivation for this $130 million undertaking is medicinal: About 25 percent of modern pharmaceuticals are derived from plants. Although seed banks have limitations– as seeds lose viability over time and cannot always be regenerated– they still constitute a last line of defense in the campaign to save biodiversity.
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What Lies Ahead
Indians of the Colombian Amazon learn their place in the world as children by studying a map of their homeland that is closely tied to legend. Names and spirits are ascribed to key features in the environment, be it an animal, tree, brook or marsh. Indians are taught to see the different aspects of nature as entities with whom they have vital relationships. If the environment comes to ruin, so do they.
This perspective is missing in industrial societies and is sadly starting to seep away from the indigenous peoples of the Amazon as their contact with "civilized man" increases. Influenced by Western ways, some Indians are coming to view the environment from an outsider's perspective, not something of which they are an integral part. The riches of nature, from this vantage point, are resources to be exploited. Trees are potential sources of lumber, rather than creatures with whom they share an intimate history.
It is distressing to see indigenous cultures unravel in the face of intrusions from afar and witness the environmental repercussions. For those of us living in urban centers, it is harder to realize that our destinies, too, are tied up with the environment. If ecosystems collapse, as species go extinct, humans will inevitably suffer. Much of the blame should fall on the shoulders of Westerners whose demand for goods– obtained through logging, hunting and mining in remote, ecologically sensitive zones– often seems boundless.
Viewing the threats to biodiversity on strictly utilitarian grounds, it's apparent that if plants and animals continue to vanish at present rates, humans will miss out on valuable foods, drugs and chemicals without knowing what we're losing. Crop yields will suffer from the disappearance of unknown pollinators and from the susceptibility of uniform strains to disease and pests.
Beyond the economic rationale for preserving biodiversity, there is– or at least ought to be– a moral imperative. Ultimately, our goal should be to defend the fruits of evolution– a process that has taken billions of years to unfold and may not be repeated on a human time scale. The fact that species extinction is a consequence of evolution and an important part of the natural order does not excuse reckless human activities that inflict undo harm on the biosphere. Representatives of the Homo sapiens species ought to live up to a name that suggests a modicum of wisdom. We need to exercise restraint, while striking a balance between our short-term gratification, long-term needs and the interests of life in general.
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Rethinking The Future
This is a personal note related to our catalog's theme of biodiversity.
As a biologist first and a businessman second, I am very concerned about the vast loss of biodiversity that will occur this century. For 200 years, Homo sapiens has altered the Earth to such an extent that the world's forests, fresh water and marine ecosystems are threatened. Many biologists consider the present appropriation of the Earth's resources the beginning of the greatest extinction of living organisms ever. It seems strange that we are willing to spend hundreds of millions of dollars to look for life on Mars while ignoring what's happening here on Earth.
So what are the reasons and how can we change this situation? In his book, The Future of Life, E.O. Wilson suggests that overpopulation and wasteful consumption are primary causes for this impending disaster. I will add a third-economic growth.
The current addition of 200,000 new humans each day translates to a population of almost 9 billion by the middle of this century; many of us question whether this is sustainable. However, developed countries are already heading towards zero population growth. With greater emphasis on education and the empowerment of women, developing countries may soon follow.
Wasteful consumption has been out of control in many countries, especially ours; a major social attitude change is necessary. And it's starting. Recycling, increased industrial efficiencies, smart growth and global conservation are on the books.
But what about economic growth? With an expanding population using 50% of the Earth's land area for primary production by mid-century, can we still preach that economic growth means human betterment? Preserving biodiversity will require a solid change in economic idealism. Perhaps a Nobel Prize is waiting for an economist that can design a system with no net growth that still produces meaningful technological advances. In the meantime, let's learn to live well on less and remember that small is beautiful. We all need to recognize that the Earth's biodiversity is our future.
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NEB Nature Conservancy
For over 25 years, the NEB Catalog has been a resource for scientists around the world. Now, we dedicate some of its pages to raise awareness about the impact of biodiversity on the well-being of our planet. As part of this effort, New England Biolabs will offer support to IDEA WILD, a group dedicated to helping preserve the Earth's biodiversity.
IDEA WILD was founded in 1991 to minimize the loss of biodiversity by empowering people who work on the front lines of conservation efforts in developing countries. In eleven years, IDEA WILD has provided binoculars, mist nets, telemetry equipment, climbing equipment, software, computers, printers, global positioning systems, boats, motors, slide projectors, video and 35mm cameras and other equipment, directly to more than 600 conservation projects in 30 countries. IDEA WILD encourages equipment transfer from one project to another when the first is completed. On average, the equipment cycles through at least three projects. Consequently, over 1800 projects have used, or are currently using, equipment provided by IDEA WILD.
Hundreds of theses, management plans, technical reports, scientific papers, videos and educational materials have been created with the enormous amount of data collected with these equipment donations. Professors, graduate and undergraduate students, non-profit staff and other nationals have all gained experience and skills using donated equipment. Equipment recipients have filled positions in national parks, eco-tourism operations, zoos, universities, non-profit organizations and government agencies with individuals experienced in biodiversity conservation. Recipients create new reserves and parks, manage and monitor already existing nature reserves, study threatened and endangered species, promote sustainable harvest of natural resources and conduct public education. Ultimately each individual helps to minimize the loss of biodiversity.
IDEA WILD has also created mutually beneficial relationships with numerous equipment suppliers, resulting in discounted equipment and enabling more projects to be funded per donation dollar. IDEA WILD receives funding from direct mail appeals, slide presentations, merchandising, benefit auctions, individuals, corporations and private foundations. Funding has increased every year since 1991...IDEA WILD is just getting warmed up! If you are interested in conserving biodiversity, become a member of the IDEA WILD team by donating equipment or funds, transporting equipment or by providing funding opportunities within your company or institution.
IDEA WILD
420 Riddle Drive
Fort Collins, CO 80521
970-482-6748
ideawild@ideawild.org
www.ideawild.org