According to all past experience, current ecological theory and fact, Kridler is speaking the uncomfortable truth. If the Leewards were exposed to what is sometimes called civilization, the wildlife that currently finds sanctuary there would be devastated within a matter of years. A few military landing exercises, an airstrip, a marina, even regular visits by such sensitive parties as bird watchers, photographers and skin divers would create havoc.
Island life has fascinated natural historians ever since they began to take a clinical look at biological dynamics. The whole theory of evolution might well have come to us in a different form, at a different time and from a different agent had not Charles Darwin sailed on the Beagle and been exposed to and pondered on the wildlife of the Galapagos. On island habitats the principal evolutionary forces—mutation and natural selection—seem to work with great rapidity, and their effects are more observable than on continents, where more complex pressures operate. One well-documented phenomenon of island life is its fragility. Subtly adapted, intricately specialized to the peculiar conditions of their isolated habitat, island species have far fewer options than mainland creatures if their environment is suddenly changed or new environmental factors are introduced. The natural history of Hawaii during the past century serves as a classic illustration of this vulnerability.
Originally there were two mammals, the monk seal and the bat, no reptiles and only two insignificant predators, a small owl and a hawk, on the main Hawaiian islands. The vertebrate population was made up largely of a number of gentle woodland and water birds living in a kind of biological Eden. Western man (and to a lesser extent, because he had less energy at his disposal, Polynesian man) came on these delicate creatures like a panzer division on an open Balkan village. The basic environment was drastically altered by new agricultural, commercial and domestic uses. Forests were reduced, swamps drained and water and land contaminated in a variety of ways. All of this happened in much the same manner in the continental United States, of course, but with less noticeable and immediate effects on wildlife. When a forest was cut or the land plowed, it disrupted the habitat and lifestyle of, say, a wood thrush but often there were odd, overlooked corners into which the bird could retreat and make do after a fashion. However, when the relatively few acres of woodland habitat in which the Lanai akiola of Hawaii had become a specialized resident were destroyed, there was no place for this species to flee, no alternative to extinction.
Even more dramatically, invading men brought with them, intentionally and unintentionally, a host of hostile camp followers—various weed plants that choked out native species; mosquitoes carrying new strains of avian malaria; rats, mice, cats, dogs, pigs and, perhaps most unfortunately of all, the mongoose. Beautifully adapted to their tiny microenvironments, the specialized island natives could not cope with these new life-bending forces. Without immunity to the introduced diseases, innocent of normal predatory relationships, having no space in which to fall back, no time in which to develop the necessary defenses, the Hawaiian birds succumbed quickly. During the past century 24 species of birds, found no place in the world but Hawaii, became extinct. By way of comparison, in all the rest of the U.S. in 3� centuries only six species of birds are known to have become extinct.
The situation on the islands continues to deteriorate. Of the 50 species of birds in the United States judged to be endangered, whose chance of survival is regarded as slim, over half of them are natives of the Hawaiian Islands. The names of many of these creatures—io, koloa, oo aa, Maui nukupuu—are exotic and totally unfamiliar. Many of the species are small rain-forest creatures. In point of fact, quite a number of these birds may be as improbable as their names. It has been so long since some of them have been reported, or the reports are so vague and unsatisfactory, that possibly half a dozen or more of the species are already extinct and all that now can be done for them is to write their ornithological obituaries. A good many students believe that by the end of this century none of these endangered species and very few native species of any sort will survive on the main Hawaiian islands. Even if these dire predictions do not prove to be completely true, there is no disputing the fact that during the past 70 years the land of aloha has been the most lethal in the world for wildlife.
It was against this background of disaster, at a time when it appeared that the happenings on the main islands would be repeated on the Leewards, that the national refuge was established. In the first few years of this century hunters found the monk seals in the western islands of the archipelago, eliminated the animals from some islands and reduced them to the status of a rare creature everywhere. At the same time, merchant and fishing ships were visiting the islands and filling the vacant space in their holds with sea turtles. Turned on their backs, helpless, the big reptiles would stay alive and provide fresh meat for months. On Laysan Island the manager of the guano digging operations set up a permanent residence for himself and his family and brought in a few hutches of domestic rabbits, again to provide fresh meat. When the family abandoned the island, the rabbits were turned loose and left behind. Within half a dozen years the multiplying rabbits had stripped most of the foliage from the island, and in doing so, eliminated three species of terrestrial birds, the Laysan rail, apapane and miller-bird. With the disappearance of the restraining vegetation, sandstorms began to sweep the island at frequent intervals, and thousands of nesting sea-birds were pinned down, buried and destroyed. Finally, having literally eaten themselves out of house and home, the rabbits themselves died.
It is for such reasons that the Bureau of Sport Fisheries and Wildlife now treats the sanctuary as one might an incubator infant, trying to isolate it from the world. However, the sources of biological contamination are so varied and subtle that despite their best efforts, the plague already may have been introduced. Several years ago an unidentified military commander is said to have decided Laysan Island would be a good place for his troops to spend a day practicing landing tactics. The immediate, obvious effect of this illegal entry was negligible but the long-range consequences were terrible. Apparently a few mustard seeds were lodged in the tracks of one of the landing vehicles. At least, that is the theory, for the next season mustard was thriving on Laysan, and since then the tough, aggressive weed has continued to spread, altering the nesting habitat and possibilities for a number of birds. Not wanting to use herbicides and able to visit the island only infrequently, Kridler and Olsen have attempted to weed out the mustard by hand, but it is apparent they are fighting a losing battle.
In the winter of 1971 a Japanese fishing boat ran aground and was abandoned on the reef of Laysan, which seems to be the hard-luck island of the archipelago. "When we heard about it," says Kridler, "the first thing we thought of was rats. We got in touch with the captain and asked if he had any rats on the ship. He said, 'Of course not, I keep a clean ship.' Later we got out there and looked over the wreck. We found rat poison, which was suspicious, like a trout in the milk. However, we've combed the island carefully and as yet haven't found any rats. They could appear in the next year or two, but maybe we got lucky this time.
"There are any number of things that might be fatal on the islands, and most of them are hard to detect. A few plant seeds, an insect or insect eggs clinging to gear, fungus spores, bacteria, virus, to say nothing of big things like rats—any of them could do it. If we opened the refuge to any more use than now, no matter how careful and good-hearted the users might be, there is a strong probability one or a combination of these accidents would occur. It is my feeling that if we permitted general or unrestricted use, we would in a few years lose the four endangered species of birds and possibly the seals and turtles, and that the seabird colonies would be greatly reduced. Just knowing what we do now, I don't see how we can take the chance. We have too much to lose."
There is not an evolutionist, ecologist or conservationist who would substantively disagree with Kridler's estimate. As near as anything can be a biological fact, it is one that if the Hawaiian Islands National Wildlife Refuge were opened to only moderate use by the public that owns it, most of the creatures who use it as a refuge would not be able to survive there for any length of time. Granting all of this, the second formidable horn of the dilemma remains—what is the use of a thing or place that cannot be used?