100 Under 100

by Scott Leslie

  FABULOUS GREEN SPHINX OF KAUAI

  One of the largest insect groups with over 100,000 species, moths range in size from barely bigger than a pinhead to the giant Atlas moth of southeast Asia, whose wings can eclipse a good-sized dinner plate. Moths are everywhere—one glimpse at a streetlight on a warm summer night anywhere in the world attests to this. So though it might seem strange to utter the words “moth,” “rare,” and “endangered” in the same breath, it’s not for the whimsically named “fabulous green sphinx of Kauai,” a native Hawaiian moth hovering at extinction.

  First observed in 1895 on the island of Kauai (it has been found nowhere else in the world), this exquisite large moth, with its bright green wings and orange antennae, wasn’t seen again for another 66 years. After this second fleeting glimpse, a few more decades of absence was enough to convince scientists to list it as officially extinct in 1996. But species sometimes have a way of coming back from the dead and, during a search in 1998, a few fabulous green sphinx moths re-emerged Lazarus-like, moving it out of the gone-and-never-to-return category in 2003. Since then, only about a dozen of the moths have been seen, most of them drawn to powerful lights at a US Air Force tracking station that sits on a hill just above their habitat.

  The fabulous green sphinx has only ever been observed in mountain forest in Kauai’s Koke’e State Park, a cornucopia of rare plants and trees, many of which are found nowhere else. Degraded by introduced goats, pigs, and axis deer, this forest is one of the most endangered ecosystems in the world. Little is known about the green sphinx moth aside from where it lives. The species’ caterpillars have rarely been observed, and its host plant (the one it lays eggs on as adults and feeds on as caterpillars) is still a mystery. Moreover, the exact reason for the moth’s rarity is also unknown. Perhaps the introduced goats or invasive exotic plants have decimated the population of the moth’s as-yet-unknown host plant? Maybe the ferocious Argentine ant, another invasive pest, is taking its toll by attacking the caterpillars? Nobody is sure. Ironically, because so little is known about this mysterious insect, it is still not protected.

  Far to the south, across the vast Pacific Ocean, the future of a fellow six-legged creature looks just a little bit brighter.

  LORD HOWE ISLAND GIANT STICK INSECT

  If there is one group of creatures on this planet that we’d consider abundant, it is the insects. A thriving multi-billion-dollar pest extermination industry is testament to that. But you won’t be needing pest control for the Lord Howe Island giant stick insect anytime soon. In fact, so rare is this bizarre organism that it was thought to have completely disappeared by 1930, done in by stowaway rats from a ship wrecked earlier in the century on the shore of this remote Australian island, about 650 kilometres off the coast of New South Wales.

  Picture a typical stick insect, and a wispy, twiggy bug may come to mind—in fact, the largest, a species found in China, is practically all legs and 60 centimetres long! The Lord Howe species doesn’t quite fit that mould. Not that it isn’t strange with its chunky, cigar-shaped body (about 15 centimetres in length) and its short, stubby legs. It’s also a heavyweight among insects, tipping the scales at 30 grams—that’s heavier than many songbirds. A more fitting moniker for the big black insect is the “land sausage,” another of its nicknames.

  For decades nobody had seen the stick insect, until it was rediscovered in 2001 by Australian biologists. Oddly enough, it was found not on Lord Howe Island but 22 kilometres across the open Pacific Ocean on tiny Ball’s Pyramid, a jagged, uninhabited 600-metre-high fang of volcanic rock, the world’s tallest sea stack. According to geologists, Ball’s Pyramid was never attached to Lord Howe Island, and giant stick insects can’t swim. Nobody knows for sure how the insect got there. The best guess is that the first ones may have been accidentally carried in the nesting material of one of the thousands of seabirds that breed on the precipitous crag. Or maybe a female stick insect laden with eggs got washed into the sea during a storm and was lucky enough to drift over on some flotsam. However they got there, only about 20 individuals have survived on that desolate rock for the better part of a century. Even more remarkable is that all of the Lord Howe Island giant stick insects left on earth were discovered under a single bush growing in a cliff crevice a dizzying 90 metres above the crashing waves.

  Once the biologists returned to the mainland, they got to work devising a recovery plan. The idea was to take a few individuals from Ball’s Pyramid and captive-breed them into a population large enough to ensure the survival of the species in the wild.

  Despite the precariousness of the tiny population, the biologists had to fight with bureaucracy to get permission to revisit the island and capture the animals. Two full years passed before their return in February 2003. That’s a long time in the life of a species with just a handful of members left, so the scientists had no idea whether the beleaguered bugs still existed on Ball’s Pyramid. They did. Two male and two female giant stick insects were collected for captive breeding back on the mainland.

  Since then, the number of Lord Howe Island giant stick insects in the breeding program at the Melbourne, Australia, zoo has topped several hundred. Smaller numbers have also been bred at other zoos. Recently, 10 males and 10 females from Melbourne were returned to Lord Howe Island to live in a special enclosure. It is hoped that a full reintroduction can be made some time after 2011, once a rat eradication program is completed.

  It isn’t known exactly how many of the giant insects survive today on Ball’s Pyramid, but the population is thought to be very, very small—likely fewer than 20.

  LOST FROM THE FOREST:

  TREES AND OTHER PLANTS

  When we think of endangered species, it’s easy to forget about the plants. Of course, they are every bit as alive as animals and are born, grow, reproduce, and die just like us, but their individual lives are generally thought to be less important. Nothing could be farther from the truth, really. Plants are primary producers, which means they can do something animals can’t. Using photosynthesis, they trap the power of the sun, mix it with a little water and a few minerals, and create themselves. It’s about as close as you can come to getting something from nothing. Good thing, too, since we in the animal kingdom ultimately depend on them for our food and would not exist without them. The key to photosynthesis is chlorophyll, life’s magic green potion. Blood and chlorophyll have virtually the same chemical makeup, except for one important difference: at the hub of every haemoglobin molecule is an atom of iron, whereas in chlorophyll, it’s magnesium.

  Photosynthesis is fundamental to what is in effect a kind of planetary respiration, an elegant global symbiosis between the kingdoms of life. Plants breathe out the oxygen that we breathe in, and they breathe in the carbon dioxide that we breathe out. What’s more, they help make the weather, are the foundation of our food web, and are important sources of medicine and building materials. From plant’s ancient fossils comes our petroleum. Without them we would perish by asphyxiation, starvation, dehydration, prostration. And, oh yes, they are beautiful to look at. To this last point, I could do no better than to add the words of naturalist Donald Culross Peattie: “True that a plant may not think; neither will the profoundest of men ever put forth a flower.”10

  The actual populations of plants and particularly trees is deceptive, however. As ubiquitous as they are overall, many individual species require very specific growing conditions and survive in quite small numbers; because of this, some have a very limited range, making them vulnerable to extinction. Nearly 1,600, or about half of all the critically endangered species on the IUCN Red List, are plants.

  WOLLEMI PINE

  For scientific accuracy, the landscape in the movie Jurassic Park might be clothed in forests of Wollemi pines. Fossil evidence suggests that 200 million years ago this wispy evergreen, with its knobby bark and fern-like spray of branches, was a dominant tree on the Gondwana supercontinent of the southern hemisphere and was eaten by many types of dinosaurs.<
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  Until recently, Wollemi pines were thought to be extinct. Then, in 1994, while hiking in a remote gorge in Wollemi National Park north of Sydney, Australia wilderness explorer David Noble noted an unusual tree growing on a canyon ledge. Botanists soon returned to the site to confirm the identity of the tree. A species thought to be long gone wasn’t. Unfortunately, there were fewer than 100 trees left, the last descendants of dinosaur-age precursors. The Wollemi pine was a living fossil hanging on by a thread.

  Growing up to 40 metres tall and with a trunk diameter of about a metre, this majestic tree is not actually a pine but a member of the ancient Araucariaceae family, which also includes the monkey puzzle tree of South America, the klinki tree of New Guinea, and the kauri of New Zealand. The famous stone logs of Arizona’s petrified forest are eons-old members of the same family.

  The exact location of the wild trees has been kept secret to protect them from the inevitably quick extinction that would result if collectors knew their whereabouts. Wollemi pines have also been propagated in greenhouses from the root cuttings of wild trees. These were made commercially available to the public through selected botanical gardens beginning in 2006. Proceeds from the sale of the cultivated trees help fund their conservation in the wild. It’s also hoped this accessible, legal supply will reduce the value of the wild trees on the black market.

  Almost all of the remaining wild trees are clones of each other (they have an identical genetic code), suggesting they passed through a population bottleneck at some point in the past when perhaps only a few individuals survived a close brush with extinction. So why is a tree that outlasted continental drift, dinosaurs, and ice ages barely hanging on now? One possibility is that because the species evolved at a time when carbon dioxide levels in the atmosphere were much higher than they are today (remember, trees need CO2 like we need oxygen), they are now simply gasping for breath, so to speak, unable to adapt well enough to thrive in the present atmosphere. But who knows? If we continue to burn fossil fuels with abandon, maybe one day there will be enough carbon dioxide in the atmosphere for the Wollemi pine to thrive once again.

  SICILIAN FIR

  The Mediterranean region is a global centre of botanical diversity.

  It’s home to about 24,000, or 10 percent, of all vascular plant species, even though it covers less than 2 percent of the planet’s surface. Half of these are endemic and are found nowhere else. Even tropical Africa, four times the size, is hard-pressed to surpass the Mediterranean’s plant diversity. And a cooler region like Canada has only one-fifth as many plant species, despite being five times as big.

  A 10,000-year history of human settlement and the development that entails, such as logging and agriculture, have resulted in many Mediterranean plants becoming endangered. An icon for the threatened botanical riches of the region is the endemic Sicilian fir tree. This 15-metre-tall Christmas tree–shaped species is considered the rarest tree in Europe. Just a handful survive.

  At 200 people per square kilometre, the Mediterranean’s largest island is densely packed with people. It’s been that way for a long time. Sitting in the middle of the Mediterranean Sea, Sicily has been on important trade routes between Europe, North Africa, and Arabia for thousands of years. Few places have experienced as tumultuous a history. Greeks, Romans, Vandals, Byzantines, Arabs, Normans, Germans, French, Spanish, and Italians each ruled the island at some point over the last 3,000 years. Nature has played rough with the island, too. Earthquakes, volcanoes (Sicily’s Mount Etna, Europe’s largest and most active volcano, violently exploded in 1669, burying many villages under hot lava), and the bubonic plague are all part of its violent past.

  When the Greeks colonized Sicily around 750 BC, they wrote that the mountains of the northwest were covered by firs. That would all change as the island’s population and economy grew. After Arabs had taken control of the island in the early Middle Ages, Sicily experienced a population boom and many of its forests were cut for lumber to build houses. Later, rampant harvesting of timber for both naval and merchant shipbuilding not only depleted its forests but also resulted in severe erosion on the steep slopes of the island’s mountains. It’s hard for trees to grow when the soil has been washed away. Centuries of goat grazing only added to the problem. Not surprisingly, the Sicilian fir was becoming very rare. By 1900, it was thought to be extinct.

  It was rediscovered in 1957, when a few trees were found in rocky soil on the slopes of the Madonie Mountains in north-central Sicily, in what today is a large regional park. Although surrounded by a 40,000-hectare protected area, a paltry 30 mature trees confined to a 100-hectare area are all that remain of the Sicilian fir in the wild.

  Despite vigorous conservation efforts since the trees were discovered over five decades ago, the recovery of the population has been hampered by poor soil and rapid erosion where they grow and by the destruction of seedlings by grazing animals. To remedy this, protective stone walls have been built around individual trees to stabilize the soil, and each has been fenced to exclude grazing animals.

  The number of naturally occurring seedlings produced by the firs has increased slowly in recent years, and the low genetic diversity (not unusual for such a small population) has been improved through the cross-pollination of mature trees. To determine the best locations for a future reintroduction program in the wild, nursery-grown seedlings were planted in various protected experimental plots by scientists from the University of Palermo. As well, thousands of locally produced nursery seedlings are now available to the public. Once mature, these trees will be a living seed bank to ensure the long-term survival of the species. Nurseries and botanical gardens outside Sicily have also produced inventories of seedlings.

  The biggest potential threat to the Sicilian fir is global warming. Today, Sicily is facing desertification caused by hotter, drier weather and a badly eroded landscape. What’s worse, the frequency of devastating wildfires on the island has been on the rise, so protecting the 30 mature firs against this menace has become an immediate priority.

  VIRGINIA ROUND-LEAF BIRCH

  Unlike the rocky, arid environment of the Sicilian fir’s Madonie Mountains and its sparse vegetation, the moist ecosystem of the southern Appalachians of the United States boasts some of the highest tree diversity of any temperate region. This is where the first tree ever protected under the US Endangered Species Act is found.

  Rediscovered in 1975 after an absence of nearly 60 years, the Virginia round-leaf birch is found along one minor creek in the southwestern corner of Virginia. A relatively small tree at about 12 metres in height, its round leaves and aromatic dark bark are unusual for a birch. It’s also somewhat of an evolutionary mystery: scientists aren’t sure whether it’s a newly evolving species that had recently split off from a grove of similar sweet birch living nearby or the last survivor of a once-widespread species.

  In 1975, there were 41 round-leaf birch, but by the early 21st century only 8 of the original wild ones remained, brought to the brink by illegal plant collecting, vandalism, cattle grazing, and competition from other vegetation. There has been a concerted effort by the US Forest Service, the state of Virginia, and independent conservationists to recover the population since it was listed as endangered in 1978. The goal was to have 500 to 1,000 trees in each of 10 self-sustaining populations. By 2003, there were close to 1,000 nursery-raised round-leaf birch saplings transplanted alongside the original 8 wild trees. On paper this looks good; however, none of the transplants has reproduced. And the last time one of the original wild trees reproduced was almost 30 years ago.

  Very specific conditions must be met for the round-leaf birch to procreate in nature: the right size openings in the forest canopy above the trees (basically determining how much light they receive) must be present during the years they produce abundant seeds, which is only infrequently. In 1981–82, the planets had aligned for one particular tree and it produced 81 tiny seedlings. Things were looking up. That is, until vandals destroyed all of
them.

  Nevertheless, the Virginia round-leaf birch is better off today than it was a decade ago. Those hundreds of artificially grown trees that have been transplanted into the species’ original habitat have reduced the threat of imminent extinction. This fact was recognized when it was up-listed from Endangered to the less serious Threatened category in 1994. But unless any of the last eight wild trees, or at least some of the nursery-grown saplings, can successfully reproduce, the round-leaf birch will remain rare.

  On a desert island on the other side of the country, another tree lives by virtue of the US Endangered Species Act, this one with an even more precarious grip on survival.

  CATALINA MAHOGANY

  It appears this tree has always been rare. When naturalist Blanche Trask first discovered it in 1897 growing in a single gully on Catalina Island, just 35 kilometres off the California coast from Los Angeles, she found only about 40 or 50 trees. The species grew nowhere else on the island. Over a century later, the mahogany’s fortunes haven’t improved. It is still found only in Wild Boar Gully, only now its population is in the single digits. What is remarkable is that just one new tree has been added (for a total of seven) to the population of six that existed when the species was first protected under the US Endangered Species Act in 1997.