Endangered Species Handbook

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Forest

New Zealand

     New Zealand was formed some 80 million years ago when it broke off from the tropical southern continent, Gondwana (Molloy 1994).  The land mass moved away with resident pterosaurs, sauropod and carnosaur dinosaurs, along with primitive frogs, lizards, land snails, spiders and other insects and invertebrates.  It is also possible that the ancestors of the flightless moas and kiwis were present on Gondwana (Heather and Robertson 1997). 
 
     Unlike South America, New Zealand remained uninhabited by humans until a thousand years ago, allowing an extraordinary fauna and flora to evolve.  Giant trees of many types, some almost as massive as sequoias and others rivaling American Coast Redwood in height, thrived in primeval rainforests and swamps.  The dinosaurs died off 65 million years ago simultaneous with their extinction elsewhere in the world.  Over the eons, as the land moved southward, the climate cooled.  Many tropical species, unable to adapt, died out, while others coexisted with immigrant species of plants, birds and insects that arrived by wind or ocean current.  Geological and climatic events--from earthquakes and mountain uplifts caused by movements in the Earth's plates, to the weathering of wind, sun and rain--produced great changes in the topography over the millennia.  The original land mass split into two main islands and many satellite islands, and snow-capped mountains rose on the southern island.  Ice Age glaciations occurred during the Pleistocene between 2.4 million years and 10,000 years ago (Molloy 1994).  These cold periods did not, however, eliminate the majority of ancient plant or animal species, another proof of their amazing adaptability.  
 
     When the Polynesian Maori people arrived about 1,000 A.D., temperate rainforests with understories of giant tree ferns grew throughout the island's swamps, lowlands and highlands, over 80 percent of the land.  The Maori must have been stunned to see thousands of flightless birds of various sizes roaming the island.  The moas had evolved from a single ancestor into some 11 species which grazed in herds or in small groups.  Following the extinctions of the dinosaurs, moas evolved in a wide range of species able to browse vegetation in forest, shrubland and grassland habitats (Molloy 1994).  The native plants developed thorns and other means of defense against the moas.  These plant adaptations persist today, long after the disappearance of the moas, remnants of a bizarre and fascinating ecosystem.  These emu-like birds ranged from chicken-sized to a species 10 feet or more in height, the tallest bird that ever lived.  With heads disproportionately small and necks long and gangly, these down-covered birds walked about on thick, scaly legs.  Also resident on the islands was a massive eagle, weighing up to 29 pounds (Molloy 1994).  This giant bird of prey was the largest eagle to have ever lived on Earth and may have preyed on moas or soared about in search of moa carrion.
 
     On the southern island, penguins lived on rocky coasts and in wet coastal rainforests; one species was a giant, standing more than 5 feet tall (Molloy 1994).  No mammals other than bats were native.  Lizards called tuataras, older than dinosaurs, lived in many habitats on the islands.  Primitive and unusual frogs of types long extinct elsewhere were abundant, especially in mossy rainforests.  Huge, cricket-like wetas, insects virtually unchanged for 200 million years, had evolved into 70 species.  Compared to grasshoppers, wetas have heavy bodies, weighing as much as 2.5 ounces.  Scurrying about at night, their diet and behavior are rodent-like.  They are considered by zoologists to be among the most interesting animals on the islands (Molloy 1994). 
 
     The forests were dominated by trees very little changed since the age of the dinosaurs.  Three major groups of trees, all evergreens, dominated New Zealand's forests, survivors of the Cretaceous Era 135 million years ago:  araucaria, podocarps and southern beeches.  All had close relatives in South America and other parts of the world.  
 
     A single species of the Araucaria family, to which the South American Monkey Puzzle Tree belongs, dominated forests on North Island.  The enormous Kauri (Agathis australis) has a massive, wide trunk that rises to great heights before branching in a wide canopy.  Its gray, grainy bark forms deep, vertical ridges that curve upward, wrapping around the tree as it rises hundreds of feet into the air.  Verdant tree ferns, with large, short trunks, and primitive club mosses form an understory beneath them. 
 
     Seventeen species of podocarp trees survive in New Zealand, some of which reach great heights.  New Zealand's tallest tree is the Kahikatea (Dacrycarpus dacrydioides), or New Zealand Cedar, a type of podocarp which is nearly as tall as Coast Redwoods but with a slimmer trunk, often covered in epiphytic plants (Molloy 1994).  Podocarp forests were once very widespread throughout both North and South Islands, each species in a slightly different habitat (Molloy 1994).  At the other extreme is the world's smallest conifer, the ankle-high Pygmy Pine (Lepidothamnus laxifolius), a podocarp growing at high altitudes in a beautiful area known as the Southern Alps on South Island (Molloy 1994).  Another podocarp type, the Celery Pines (Phyllocladus spp), are small trees whose leaves are actually flattened stems.  One podocarp, Halocarpus kirkii, is listed as Threatened by the International Union for the Conservation of Nature (IUCN) (Walter and Gillett 1998), and all have declined dramatically in range.
 
     Southern beeches of Nothofagus, the same genus as those in South America, once blanketed South Island in dense, canopied forests, often without an understory of plants other than low ferns (Molloy 1994).  Today some forests remain, growing in association with broadleafed trees and hardwoods that arrived in New Zealand at a more recent time (Molloy 1994). 
 
     Some extremely primitive plants have also survived in New Zealand.  The largest moss in the world (Dawsonia superba), giant liverworts, clubmosses and horsetails are among these (Molloy 1994).  Tmesipteris, an epiphyte, is a relict of the earliest vascular plants, which evolved some 400 million years ago.  This rootless plant clings to the branches of trees and hangs in vine-like, leafy strings.  New Zealand's forest floor plants, a micro-world of species, most of which are less than an inch high, are beautifully photographed and described in The Forest Carpet by Bill and Nancy Malcolm (1989), a book devoted to New Zealand's mosses and related plants. 
 
     Other survivors from Gondwana include an extremely ancient family of spiders, Archaeidae.  First described from a specimen frozen in amber several million years old, seven species have been found on Madagascar, also a part of Gondwana:  one in South Africa, three in Australia, five in New Zealand and one at the tip of South America (Preston-Mafham 1991).  The Archaeidae spiders have strange, grotesquely shaped bodies, visible only through a microscope since they are only 0.14 inches long; they live among leaf litter on the ground (Preston-Mafham 1991).
 
     The beauty and primitive auras of many of the Kauri, beech, podocarp forests and pristine forest swamps evoke a "bygone era when dinosaurs still roamed the Earth" (Molloy 1994).* Beech and podocarpus forests cover South Island's Fiordland, a region along the southeastern coast resembling Norway's fiords, with inlets penetrating deep inland, lined by misty forests.  The trees are buffeted by fierce winds from the west that bring rainfall of up to 20 feet a year.  In this rugged wilderness, mosses and huge tree ferns thrive in the dampness.
 
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*Many of the primitive landscapes that survive in New Zealand were captured in Gerald Cubitt's photos in Wild New Zealand, accompanied by natural history information in the text by Les Molloy (1994).  Also, two films, “Land of the Kiwi” and “Mountains of Water,” described in the Video section, display these vistas.
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     The moas, which must have been very tame and unafraid, were hunted by the Maoris, who lived on their meat and eggs for centuries.  The last of the moas, all smaller species, are said by some authorities to have survived until the 18th and 19th centuries (Greenway 1967), although this is disputed by others who assert that the moas were killed off well before the 15th century (BI 2000).  Some Europeans claimed to have seen living moas, but no account was ever confirmed.  Millions of their bones and eggs, and a few examples of skin, are all that now remain of these birds.  The giant penguin, giant eagle and many flightless birds were also wiped out, apparently by hunting.  European settlers eliminated many more species when they cleared forests and imported animals, such as dogs, cats, the weasel-like stoat that preyed on native animals, and livestock that eliminated their habitats.  Apart from the moas, nine birds, one reptile and one mammal are known to have become extinct in New Zealand since 1500.  One of the birds, a beautiful forest songbird, the Huia (Heteralocha acutirostris), was truly unique: the male and female had different sized and shaped bills.  Hunted for its plumes, and with its habitat destroyed, the Huia was last seen in the late 19th century.  Others, including  a flightless owl; a quail; two wrens, one of which was the only known flightless songbird; a bittern; a thrush; a storm-petrel; a flightless rail; and another songbird became extinct.  A gecko and a native bat also disappeared (see Appendix for a chronological list of these species).
 
     Although the Maoris cut and burned portions of the Kauri forests, not until the Europeans arrived in the 18th century did clearcut logging begin.  Captain James Cook, the first European to visit New Zealand, noted some very tall trees that were probably Kauris while reconnoitering for lumber on his visit to New Zealand on November 21, 1769:  "I judged that there was 356 solid feet of timber in this tree clear of branches."  Millions of these great trees were felled for lumber or to clear land, leaving only fragments of the original forests.  On the Coromandel Peninsula on North Island, isolated patches of mature Kauri forest are protected in several sanctuaries where old tramways, constructed to remove the logs, still scar the landscape (Molloy 1994).
 
     Overall, approximately 75 percent of native forests in New Zealand have been cleared for agriculture and grazing land for 60 million sheep and other livestock.  Fortunately, the Government of New Zealand has set aside many large parks and reserves to preserve landscapes, forests, endemic plants and animals.  Thirty percent of the islands are protected, one of the highest rates of preservation in the world.  In the majority of western Europe, for example, less than 5 percent of the land is protected, and villages and residences are allowed in many national parks.  Not all New Zealand's ancient forests are safe from logging, however.  A controlling interest in one of the last sizeable expanses of forest, 193,000 acres on the northern end of South Island owned by Fletcher Challenge Ltd., a logging company, was sold in 1997 to the US lumber company, Weyerhauser. 
 
     Many native animals of New Zealand's forests have been pushed to the edge of extinction by a combination of loss of habitat and the introduction of exotic species.  Even the weta insects are in decline.  Nine weta species are listed on the 1996 IUCN Red List Animals (Baillie and Groombridge 1996).  All four species of kiwis in New Zealand are rapidly approaching extinction, listed as Vulnerable or Endangered by Threatened Birds of the World (BI 2000).  Authorities now recognize four, rather than three kinds of kiwi, and one, the Brown Kiwi (Apteryx mantelli), is endangered, its population having declined 90 percent since 1900 (BI 2000).  Among the most ancient of bird species and possessing many unique physical and behavioral characteristics, their loss would represent as important a biological tragedy as the extinction of the moas.  They have been placed in their own family, Apterygidae, an indication of their uniqueness.  These flightless birds, which weigh from about 2 to 10 pounds, have small, stunted wings with claws on the end that are hidden beneath a cloak of shaggy, brown, hair-like plumage, giving them a mammalian appearance.  Their long, pointed, ivory-colored bills are used to probe the leaf litter on the forest floor for earthworms and other invertebrates at night, and they can be heard snuffling as they forage.  They have short, strong legs, and long, sharp claws on their toes, used for digging and fighting (Heather and Robertson 1997).  Their food supply is ample:  200 species of earthworms live in New Zealand, with the largest species measuring an amazing 40 inches in length and 4 inches in diameter (Molloy 1994). 
 
     At the end of the kiwis' bills are nasal openings for their highly developed sense of smell, which aid them in detecting their prey.  An acute sense of smell is a highly unusual trait in a bird.  Kiwis also have sharp hearing but poor eyesight.  Such characteristics are more common in mammals than birds (Hoyo et al., 1992).  Kiwis possess other mammal-like traits, such as two functionally alternating ovaries rather than one in the female (Feduccia 1996).  In an interesting evolutionary phenomenon, where land mammals are absent, animals totally unrelated to them often develop mammal-like traits.  Kiwis mate for life and live in large burrows.  The single egg laid by the female is enormous in proportion to her size, weighing 20 to 25 percent of her weight.  It is the largest egg, proportionally, of any bird and four times the size that would be expected for a bird her size (Hoyo et al. 1992).  By comparison, a human mother weighing 125 pounds would have to bear a 25- to 30-pound baby.  The hatching process is long and arduous, taking two to three days from the time the chick begins to break out; because the chick lacks an egg tooth, it must kick its way out of the shell with its feet (Hoyo et al. 1992).  Many chicks die during this process.  When the chick emerges at last with damp feathers, its yolk sack is still connected and nourishes it for several days.  A miniature version of its parents, it is able to follow them on their nocturnal feeding trips within a few days (Hoyo et al. 1992).  (Rare footage of incubation and hatching of a kiwi in the wild can be seen in “Birds of Paradox.”  See Video section F, Birds.) 
 
     Kiwis are totally unable to protect themselves against predators, such as dogs, cats, stoats and introduced Australian Brush-tailed Possums (Trichosurus vulpecula), who kill them or prey on their eggs (BI 2000).  At least 94 percent of kiwis die before adulthood as a result of this predation (BI 2000). The possums also destroy rainforest vegetation by browsing on canopy leaves, epiphytic and ground plants; they have exterminated a native mistletoe (Molloy 1994).  Non-indigenous animals have effectively eliminated kiwis from all but a few remote parts of their original ranges.  At least one reserve, the 290-square-mile Coromandel Forest Park, has erected a fence within the Kauri forest to keep out possums, protecting kiwis and other native birds (Molloy 1994).  Elsewhere, kiwis are being killed by predators; official government protection since 1908 has not stopped their continued decline.  Feral dogs killed 500 Brown Kiwis in a population of 900 in less than two months in the early 1990s (Hoyo et al. 1992).  Another cause of mortality has been steel-jaw leghold traps and poison set out to capture Brush-tailed Possums, although recently the use of traps has been regulated to prohibit any possible capture of kiwis (Hoyo et al. 1992).  Dependence on humid rainforest habitat has also been a major factor in their disappearance, as this habitat has been destroyed by logging, fire and agriculture (Hoyo et al. 1992).  Many kiwis are burned to death in the intentionally set fires that follow logging operations, as their shallow burrows do not protect them from the smoke, heat and flames.  Often they are afield when fires are set and die in the fires.  Those not killed lose their habitat when the humus and leaf litter essential for their feeding is consumed in the fires.
 
     The Little Spotted Kiwi (Apteryx ownii) is the smallest and rarest kiwi, numbering only about 1,100 birds (BI 2000).  A population of about 950 birds inhabits the 20-square-kilometer Kapiti Island off the southwest coast of North Island (Collar et al. 1994), where it was introduced from the mainland.  Another introduced population on Tiritiri Matangi Island, a sanctuary of 543 acres off the northern coast of North Island, has adapted well (Molloy 1994).  At one time, this kiwi was found throughout the main islands (Hoyo et al. 1992).  In the summer of 2000, Little Spotted Kiwis were returned to a reserve on the mainland, a step toward their recovery.  The Great Spotted Kiwi (Apteryx haastii), the largest species, is confined to forests in extreme northwestern South Island in the southern Alps (Heather and Robertson 1997).  Although its habitat here is protected, its numbers are still declining from predation (Collar et al. 1994).  At present, no Great Spotted Kiwis are living on a predator-free out-island (Heather and Robertson 1997), and only one small population is protected by controlling predators (BI 2000). 
 
     Another highly endangered bird, and a species almost as bizarre as the kiwi, is the Kakapo or Owl Parrot (Strigops habroptilus).  The world's heaviest parrot, it weighs up to 3.5 kilograms and is the only living flightless member of the parrot family.  It is also one of the rarest birds in the world.  Once native to all but the highest mountain altitudes on North, South and Stewart Islands, Kakapos probably numbered in the tens of thousands (Collar et al. 1994, Forshaw 1989).  They may have flown to the islands at a very early date, long before the land split into North and South Islands, and gradually lost their ability to fly.  These 2-foot-long parrots have dull green plumage, mottled with brown, that blends into the vegetation of their rainforest habitat.  Known as the Owl Parrot because of large eye discs and nocturnal habits, the Kakapo has another distinction in being the only member of the parrot family to gather in male groups near a bare area where "lek" displays are performed for females during breeding season.  Males call females to the lek with loud, low-frequency, booming sounds emanating from their thoracic air sacs.  These calls are audible to humans from as far as 3 miles away (Molloy 1994).  They perform these booming calls for six to eight hours a night throughout the three- to five-month breeding season, which takes place only every three to five years under normal conditions (Heather and Robertson 1997).  Very placid and slow-moving, they are unable to defend themselves against the rats, cats, stoats and dogs that Europeans brought to the main islands.
 
     The range of the Kakapo began shrinking with the arrival of Maoris and their domestic animals, but in 1800 they were still common in central North Island and parts of South Island where their habitats had not been destroyed (Heather and Robertson 1997).  The European Stoat, introduced to the islands in the 1880s, proved an efficient predator of these parrots, eliminating them entirely from North Island and all but remote parts of South Island.  In 1970, a survey revealed that only 18 Kakapos remained--all males--in Fiordland, South Island, and these last birds were gone by the early 1990s (Heather and Robertson 1997). 
 
     Fortunately, a previously unknown population of 100 birds was discovered in 1977 on Stewart Island, a fairly large island due south of South Island, but these birds were under attack from feral cats (Heather and Robertson 1997).  After a decade of decline, all the remaining 61 Kakapos were transferred from Stewart Island by the New Zealand wildlife department to predator-free islets located off North and South Islands (Heather and Robertson 1997).  In 1997, a lone female was discovered on Stewart Island and was removed (BI 2000).  This rendered the species extinct throughout its original range.  Unfortunately, many of the parrots starved to death in their new environments because these islets lacked sufficient food.  Their natural diet of fruits, berries, nuts, fern fronds, roots, tubers, moss and fungi was abundant in the temperate rainforests and tussock grasslands of the main islands.  A 1983 BBC documentary, “Birds of Paradox” (see Video section), filmed a Kakapo chick being fed by its mother, who walked over steep terrain 3 miles each night to obtain seeds and other food for her offspring.  Kakapos can live for as long as 70 years, and this longevity has prevented their extinction, since many years pass without any successful breeding.  New Zealand wildlife officials finally provided supplemental feeding, which immediately resulted in the first surviving chicks in a decade in 1991.  A population of 62 birds survived in 1999, of which 26 were females and 36 males, including six chicks (WC 2000).  Although their numbers are slowly growing, many of the males appear to be sterile, and others have been filmed calling alone, rather than in male groups; some seem to be calling in vain, with no females responding (Hynum 1999).  An Internet website has been established to monitor these extraordinary birds: www.kakapo.net
 
     Many other native songbirds, shorebirds, reptiles and amphibians are threatened in New Zealand, and some survive only on offshore islets where predators are absent or have been eliminated.  New Zealand has had success in eliminating cats and possums from several sizeable islands off the main islands, but on North and South Islands, rats, cats and stoats, as well as European deer and goats, are uncontrolled (Molloy 1994).  Some 70 million Brush-tailed Possums live throughout both islands, and they are now endangering forest birds by preying on eggs and chicks (Molloy 1994).  Exotic plants have also invaded forests, smothering native plants and choking lakes (Molloy 1994).  There is, however, a remarkable awareness in New Zealand of these conservation problems and its extraordinary natural heritage.  Moreover, the government agencies dealing with wildlife and the environment, TV New Zealand Natural History (which makes superb wildlife films), and scientist-writers such as Les Molloy (1994) are educating the public about this natural legacy, much of which has endured for hundreds of millions of years.  Contributions of funds and expertise from many nations and organizations might aid New Zealanders in their conservation work.


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