NATIONAL PARK SERVICE Research in the Parks NPS Symposium Series No. 1

Over the past ten thousand years, human activities have brought about widespread changes in the biosphere. Early influences were the effects of fire, grazing animals, forest cutting, and cultivation. More recently other types of disturbance have burgeoned, and certain contaminants (e.g., radionuclides and pesticide residues) have become nearly ubiquitous in the environment.

Among permanent changes that have taken place is the disappearance of certain living things that were scarce and specialized or particularly vulnerable and marketable. Many more species and ecotypes are now in jeopardy. Some persons point out in complacency that such disappearances have been occurring since the beginnings of life on this planet. Others warn that the disadvantage of insecure minority species is aggravated unnaturally as all available lands and waters are taken over by the human swarming and its technological demand.

In recent decades a particularly significant development has been the increasingly rapid distribution of people and things from one part of the earth to another. As a result of this mobility, indigenous biotic communities are being modified in additional ways that are, in a practical sense, irreversible. Where exotic plants and animals become naturalized outside their native ranges, the character of invaded ecosystems is altered and primitive adjustments obscured. The progressive homogenizing of fauna and flora is part of our creeping, worldwide loss of environmental diversity (Dasmann 1968; Allen 1970).

These accumulating changes bespeak the increasing difficulty of finding areas representative of truly aboriginal conditions. If this kind of "wilderness" is important to generations of today and tomorrow, its functions should be understood and its benefits secured while some of it still exists.

Realities of the present indicate that any currently valid definition of wilderness must be hedged with expedience. If we adopt a standard of strictly primordial conditions, then it is indeed questionable whether any biotic association of today can qualify. Therefore I use the term to describe ecosystems with relatively little permanent modification by man. Thus it includes used habitats where time and biotic succession will help restore essentially primitive conditions.

Wilderness must encompass the gamut of seral stages, these being the dependence of many living things. Such disturbances as fire, wind, animals, and other irregular influences are part of the age-old pattern. Time is one of the critical dimensions in which ecosystems operate. Actually, ecosystem is another of those terms that is difficult to define with complete satisfaction. I regard it as most useful in describing associations of living things that are extensive enough, old enough, and varied enough to be self-perpetuating under their given physical conditions of substrate and climate. The term, of course, includes this environment.

Public agencies administering wilderness are coping with the realities of disturbance communities and learning, we may hope, to draw a fine line between what is natural and what is not. Whatever their efforts and degrees of enlightenment, wilderness will be as good as we can do under conditions of the present and future.

CHALLENGES TO ECO-UNDERSTANDING

It is my position that our major urgency in preserving adequate samples of remaining ecosystems lies in the long-term possibilities for scientific study. We have only begun to investigate these life associations that embody, in their capacities for biological production and self-perpetuation, the trial and error of nearly unlimited geological time. There is a convincing rationale for regarding the infinitely organized adjustments among living things as the ultimate complexity in the universe as we know it. This is, literally, a limitless field for useful understanding, requiring long-term effort and new technical approaches.

Whatever continuing challenge these unknowns may pose, there is also an element of immediacy in our need for ecological knowledge. Looking backward to early origins, one might say that mankind has a generic history of 2-3 million years. Such a perspective is poor orientation for events in this fast-moving century. We find ourselves at a geo-instant when rapidly accelerating increases in population and resource impacts threaten a large-scale reduction of environmental quality, which is to say carrying capacity. The long-evolving human culture is confronting its ultimate test—that of making a durable ecosystem of the entire earth, which we now use or occupy. Adaptation on such a scale at the necessary rate is something new to the organic world. The technology that broadened the resource base and produced today's population and environmental problems is now the only hope of solving them.

If mankind is to survive on terms we may regard as respectable, it must be our great preoccupation in the century ahead to convert the present unplanned, worldwide disturbance condition into something orderly and durable. Our earthly support system must be renewed as it is used, and thus rendered capable of sustaining our species into the in definite future. Inevitably, this assumes a reduced and relatively stable population, which will continue to refine its level of living according to changing standards. It is a fact of life that we cannot and need not anticipate long-range specific problems and accomplishments.

There should be nothing disconcerting about this, for in the face of unmanageable complexities, the ecologist frequently finds himself dealing in trends and influences. Unquestionably, the development of new knowledge and finding ways to apply it are the hope for lasting human benefits and security. The constructive outlook is for continuing improvements in managing the vegetation and animal life that constitute our production mechanisms in the biosphere. The intensity of land and water use ranges from totally unstable crop monocultures on the one hand to self-maintaining forests, grasslands, watersheds, and scenic spaces on the other. The monocultures must be observed over time for a full evaluation. The renewable systems need experimental management to determine their best use for human benefits. In all situations there are applications for what we know of the primitive order, its internal controls, its preservation of site, and its flexibility under change. It should be evident in today's society that those who do not recognize the natural order are having great difficulty recognizing unnatural disorder. In wilderness there is much to be learned of such things.

The above social incentives to preserve and study wilderness are not widely understood. They tend to be abstract and of low priority relative to the immediate concerns of individual citizens. They are poorly supported, as might be expected where a cause seems to require costs in the present and promises benefits in the future. There appear to be few aggressive exponents of what is everybody's business. In any event, our budgetary processes being what they are, it is likely that natural areas would seldom be set aside and they would be little studied simply on the basis of incentives I have just described.

Fortunately, there is a much more effective justification for research on natural areas. The agencies administering land have a pressing concern with management, which demands a factual foundation. Storey (1968) has listed a broad array of research needs that pertain especially to the multiple-use responsibilities of the U.S. Forest Service and the Bureau of Land Management, although the results of such work have much wider applications on public and private lands. Obviously, much of the research on renewable resources will not be carried out on wilderness areas, but the primitive ecosystem or its facsimile furnishes indispensable baselines and check points for comparisons that must be made.

The National Park Service was the first public agency to be given specific responsibilities in wilderness preservation, via the now-famous wording of the act of 1916, which declared that the newly established Service would manage its lands ". . . to conserve the scenery and the natural and historic objects and the wildlife therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."

These ideas were largely repeated in the Wilderness Act of 1964, which asserted the intent of Congress ". . . to secure for the American people of present and future generations the benefits of an enduring resource of wilderness." It was provided that the federal areas so designated ". . . shall be administered for the use and enjoyment of the American people in such manner as will leave them unimpaired for future use and enjoyment as wilderness . . ."

We may be thankful for the high-minded idealism that went into the rhetoric of some of our land-use directives. However, individual national parks are seldom established in an ecological frame of reference. Boundaries have been decided primarily as a result of land ownership and political considerations. The consequent management problems were pointed out by the Advisory Board on Wildlife Management in the National Parks in its report to Secretary Udall (Leopold et al. 1963). The board noted that "Few of the world's parks are large enough to be in fact self-regulatory ecological units; rather, most are ecological islands subject to direct or indirect modification by activities and conditions in the surrounding areas. These influences involve such factors as immigration and/or emigration of animal and plant life, changes in the fire regime, and alterations in the surface or subsurface water." Accordingly, as pointed out by Houston (1971), management that must draw upon research in the parks frequently is directed toward ". . . preventing or compensating for man's altering of natural ecological relations."

THE RECREATION VALUE

Government acts and documents pertaining to wilderness consistently reflect the view that the principal justification for setting aside such areas is "recreation." This concept ranges all the way from a sometimes-heard generalization that "if people can't get there, what good is it?" to a sensitive assumption that the human being has an innate need for intervals of isolation privacy, spiritual refreshment, self-accompaniment, and even darkness and silence. There appears to be a growing recognition that under too much public use a wilderness habitat ceases to be wilderness and that in some degree this kind of recreation is self-defeating. A notable statement of the Outdoor Recreation Resources Review Commission (1962) was that "In theory, the validity of wilderness areas and other so-called 'natural areas' as ecological controls is inversely proportional to the intensity of recreational impact on them." The ORRRC group was particularly impressed with the esthetic contribution of natural scenes to the total landscape.

The Public Land Law Review Commission (1970) was little concerned with the wilderness idea, but it too acknowledged the problem of preservation in the face of increasing recreational use: "The values for which national parks and wilderness areas have been set aside should not be destroyed by an over-use for intensive outdoor recreation purposes." The report saw the possibility that population growth and increasing recreational demand could "overwhelm" such areas, and it recommended the immediate setting of use limits by a rationing system. This undoubtedly will be the way of the future, the real question being whether we will anticipate and avoid the heavy damage that is possible.

A critical parameter, and one commonly neglected in appraisals of the recreational value of wilderness, is the time dimension. Logically, over unlimited time, a protected wilderness can sustain the use of unlimited numbers of people. In the short run, it cannot be overloaded without going out of business as a wilderness. Thus the concept of wilderness as a recreational resource is sound only if we concede that mass benefits must accumulate slowly. If we insist on anything more, we are consuming our resource capital rather than collecting the interest.

In view of all the above considerations, it seems valid to conclude that both the scientific and recreational values of natural areas are long-term human benefits, and that any attempt to force them into a different pattern will inevitably be unsuccessful. This exemplifies the conservation outlook that resource use must be a planned cultural continuum rather than an episode of consumption perpetrated by a self-interested generation of men.

THE ISLE ROYALE ECOSYSTEM

With this background. it should be instructive to examine the connotations and applications of 13 years of biological research in Isle Royale National Park. I refer specifically to our Purdue University studies of several mammalian species, most notably the wolf (Canis lupus) and its prey, moose (Alces alces) and beaver (Castor canadensis). This work began in June 1958. and here I draw upon results of three doctoral dissertations (Mech 1962; Shelton 1966; Johnson 1969) and two post doctoral programs of 3 years each (Peter A. Jordan, 1963-66; Michael L. Wolfe, 1967-70). In winter most of our observations have been made from a light, ski-equipped aircraft from late January to mid-March. Summer work on roadless Isle Royale has involved extensive use of the hiking trails. The research has been supported principally by grants from the National Science Foundation and the National Park Service.

This Michigan island of 644 km² (210 miles²) lies in northern Lake Superior, at different points 24-29 km (15-18 miles) from the Ontario shore. Its ancient basaltic and conglomerate bedrocks are covered by shallow, largely organic soil and an interspersion of two vegetational climaxes: the boreal spruce-fir forest and the northern Lake States hardwoods, the latter characterized by hard maple and yellow birch (Linn 1957). The fauna is distinctly limited as compared with the adjacent mainland (Mech 1966), the most influential mammalian herbivores being moose, beaver, snowshoe hare, red squirrel, and one species of mouse. The principal carnivores are wolf and red fox. Notably absent from this list are the white-tailed deer, porcupine, raccoon, skunk, and black bear. In winter few avian predators are present, and small bird populations are highly variable from one winter to the next. The island harbors only one species of grouse (a remnant population of sharptails) and only two species of snakes.

The significance of research findings will be discussed relative to some of the questions or problems to which they apply. Supporting details may usually be found in the references cited, including investigations previous to our own. However, the most recent work is unpublished and will be referred to in only general terms. My present purpose is to illustrate the pertinence of wilderness research in adding to our fundament of biological knowledge and to the factual base of management in the National Park Service.

THE QUESTION OF STABILITY

It probably can be regarded as an ecological tenet that "old" biotic communities that integrate many species are more stable than what are usually more recent associations composed of relatively few kinds of living things. Thus, with greater complexity and long-standing adjustments, there are more governing mechanisms to counter the effects of changing conditions or variations in the status of individual species (MacArthur 1955).

Since the recession of glacial ice, Isle Royale has had about 9000 years to accumulate its present fauna. The limited diversity of vertebrate life and the fact that the island range is relatively small as a habitat for the larger species of mammals suggest that it should offer an outstanding example of biotic instability. The record is not entirely clear in this respect, and a longer period of observation may be necessary for reliable interpretation. There have been major fluctuations, but at least some of the faunal changes on the island probably are related directly to historic events on lands north of Lake Superior.

Early in the century, logging and burning were converting the north-shore country from a woodland caribou habitat of forests and muskegs into brush and early tree successions favorable to moose. Moose colonized Isle Royale (probably by swimming) before 1910, and the caribou that had been residents or migrant visitors disappeared in the twenties (Mech 1966). At that time there was no effective big game predator on the island. Moose built up rapidly to a level of heavy overpopulation and practically wiped out the available browse. A moose herd that may have numbered 3000 or more was drastically reduced in the early thirties by malnutrition and disease (Murie 1934; Hickie 1936).

Furbearers were heavily trapped on Isle Royale during the century previous to establishment of the national park, in 1940. The once-plentiful martens disappeared about the time moose were becoming established. Lynx lasted about 20 years longer and were not seen after the early thirties. At that time, the heavy destruction of ground cover by moose browsing may have been involved with a reported scarcity of hares, which in turn could have affected the welfare of the lynx, but this is entirely speculative. Beavers were increasing, coyotes probably were building up, and some foxes were present. The two canids undoubtedly scavenged on moose as a primary food supply.

In the drought of 1936 a fire removed forest cover from about a quarter of the island (Aldous and Krefting 1946). This large burn supported a regrowth of browse as moose built up again in the forties. The island appeared headed for further cycles of browse depletion and moose die-off. Krefting (1951) reported a substantial loss of moose and a decline of the herd in 1948-49. At this time a major reduction of beaver began—probably extending to the mid-fifties—which Shelton (1966) associated with an epizootic of tularemia that decimated beavers widely in the northern Lake States. Krefting (1969) found that coyote scats of this period contained moose, beaver, and hare, in the order named.

A breeding pack of wolves evidently reached Isle Royale in the winter of 1948-49, although individuals may have been there or visited the island previously. They found feeding conditions on moose and beaver (almost exclusively their foods in this range) quite favorable. In the fifties they increased as coyotes declined. In 1957 James E. Cole of the National Park Service recorded the last coyote track. It appears that an intolerable food-niche overlap and/or behavioral conflict led to the disappearance of the smaller canid. Since that time, at least, the red fox has prospered on Isle Royale, as a winter scavenger on wolf-killed moose and as a predator on snowshoe hares (Johnson 1969). Wolves on the move (i.e., hunting) kill an occasional fox, but at a moose kill when full-fed, they commonly pay little attention to the foxes that frequent such environs.

Intensive work on the wolves began in the winter of 1959, and for the next 5 years the total population was relatively stable at minimum levels of 20-22 animals. The one large pack on the island numbered 15-17, with groups from one to three comprising the remainder. From 1964 to 1966 there were increases accounted for by pup survival to midwinter, and total numbers probably were 25-28, with the large pack showing one count of 22 in 1964. This pack usually numbered 11 or 12 in 1966, after which the dominant male (who was disabled) evidently was killed (Jordan et al. 1967). This marked a signal change in the pack structure of island wolves; packs numbering six to eight were the large groups for 2 years. A pack of seven, containing four melanistic individuals, crossed the ice from Canada in 1967, bringing the island count to a probable 30 in that winter. In 1968 a pack of six probably left the island via the same route, leaving a group of seven as the largest aggregation and a total population of 17-20. For the following 3 years, this pack continued to be the single breeding pack on the island, showing a maximum count of 10 in 1971. During the same period, the total population was 17-19.

Wolf numbers have been relatively stable, with a low rate of recruitment, the greatest changes occurring as a result of an uncommon exchange of packs with the Ontario mainland. The wolves evidently have brought a high degree of stability to the moose herd, which has numbered about 1000 animals as of midwinter in recent years (Jordan et al. 1971). Although vegetation studies have not been part of this investigation, it is evident that browse species on the island have made a substantial regrowth since the advent of wolves at the end of the forties. In the large burn of 1936, aspens and other food trees have grown beyond the point of high productivity.

On Isle Royale there is a long-term trend of forest maturation that will reduce food supplies for the moose and, in turn, for the wolves. Support of a moose herd at the present level will require recurring fires to induce a patchwork of early successions. As of midwinter the island has about one wolf per 50 moose, which seems to be a maintainable ratio. Beavers evidently contribute about 15% of the annual diet.

If wolves had not reached Isle Royale, it is reasonable to suppose that the fluctuating moose herd would have greatly reduced annual browse production. Eventually, they probably would have achieved a relative stability at a low level of numbers, with the heaviest mortality brought about by malnutrition in the most severe winters. This condition has been described by Houston (1971) for moose in Jackson Hole, elk in certain Yellowstone herds, and elk and mule deer in Glacier National Park. Adjustments since the coming of the wolf to Isle Royale promise, by analogy, somewhat different habitat relationships for the north Yellowstone elk herd if wolves build up there and become a major limiting factor. In that case vegetation would be protected at a higher level of productivity, and a larger turnover of elk would be available to feed the wolves. This might well be a closer approximation of primitive conditions than what has developed since the early period when wolves and mountain lions were extirpated (or nearly so) in the Yellowstone region.

It is evident that this brief faunal history of Isle Royale is pertinent to certain basic management problems of the National Park Service. In particular, it supports the realistic policy that recognizes fires as a part of wilderness dynamics, and it emphasizes what might be expected from achieving a predator-prey balance in such areas. It has other implications which will be discussed.

PREDATION BIOLOGY

The relationships of predators to their prey have come under increasing study, and our biological understanding has been substantially improved in the past decade. The subject cannot be reviewed here, but certain features of the Isle Royale findings will be pointed out. The most nearly comparable published work is that of Murie (1944) on the wolf and Dall sheep in Mount McKinley National Park.

Thirteen years of continuous work have permitted us to examine the remains of more than 600 moose that died naturally on Isle Royale, by far the majority of which were wolf kills. Moose were "aged" originally by tooth wear, but more recently by cementum annulations (Wolfe 1969). Selective killing by the wolves has been evident since the first winter (Mech 1966).

Calves are under-represented in this sample because their remains are highly perishable and often almost totally consumed. But calves sustain the highest predation rate of any single year class. In most winters about 25% of animals killed by the wolves are calves, a rate that may more than double in the presence of exceptionally deep snow. Under these conditions also, the killing rate increases and carcasses show a lesser degree of immediate utilization.

From age 1 through 5, few moose are killed, after which vulnerability increases to the greatest known age (three specimens) which is 17+ years. Advancing age and the incidence of killing by the wolves are correlated with more frequent evidence of several kinds of pathology, including peridontal disease, arthritis and bone deformations, and heavy infections of the hydatid tapeworm (Echinococcus granulosus). Michael Wolfe is preparing for publication a life table and mortality and survivorship curves for this moose herd based on 374 specimens accumulated through 1968. The great significance of this information is that it portrays something close to the natural age structure of a moose herd under the culling of its principal predator, the wolf. Only in a protected wilderness, where both moose and wolf are free from man-caused mortality, would such research be possible. Vital statistics show that the wolf "manages" its prey by removing poorly protected calves at one end of the life cycle and the least healthy adults at the other, leaving the more vigorous segment of the population to utilize available browse in producing more generations of moose.

This is a view of an ancient biological mechanism that has helped preserve this type of ecosystem. The highly selective pattern of wolf predation has had its evolutionary effect on the moose. The gun obviously has a different kind of effect. Thus, where big game herds are limited primarily by the annual hunting kill, it can be expected that, over time, speciation will be directed along unnatural lines. This suggests the inadvisability of attempting to manage any animal immune from the attentions of its natural enemies. Questions of this kind must likewise be raised relative to those big game herds in parks that are stabilized at low level by the deficiencies of a long depleted range.

WOLF SOCIOLOGY

When wolves were first known to be on Isle Royale, a major question was, how numerous would they become? In the region it was popularly assumed that they would undergo a build-up to be limited only by disappearance of the moose. Actual densities achieved have fluctuated around a mean of about a wolf per 16 km² (10 miles²). Pimlott (1967) regarded this as the maximum density for most ranges. Population control has been effected by an extremely low recruitment rate brought about by a severe limitation on the number of females that breed, plus a low survival of young. Only for short periods has more than one breeding group been present on the island. Usually sexual activity is seen in only one pack, the largest at the time, which may be considered "dominant" in having territorial rights to at least half the island.

We have two records of a wolf being killed by its own kind. One such case has been referred to—elimination of the ailing dominant male of the large pack in 1966. The second occurred in 1969, when it appeared that the (then) major pack encountered a lesser group at or near the territorial boundary. Two, or perhaps three, cases of wolf injury through fighting were recorded when the immigrant pack of seven arrived on the island in 1967. These episodes might be regarded as incident to disruptions in the commonly existing social order, but they are part of the wolf's population dynamics. Ordinarily, the social hierarchy and its inherent behaviorisms are a peace-keeping type of organization designed to enhance genetic superiority and the cause of racial survival.

Since only a few individual wolves can be recognized in our surveillance from the air, the significance of many behavioral observations is questionable. However, dominant animals (alphas or betas) can be identified frequently, and subordinates often leave no question of their status. Pups of the year may reveal themselves by a combination of behavior and appearance.

It is logical to expect that a dominant carnivore be self-limiting in numbers. The wolf on Isle Royale fulfills this expectation by mechanisms that are by no means explained fully. For example, we know nothing of socio-economic relationships that might be critical during the denning season. By whatever means, it appears that the wolf has achieved the maximum density that is socially tolerable under these conditions. If this is true. then numbers of the moose have been controlled secondarily through some realistic relationship between supply and demand. This relationship is not a constant, for moose vulnerability is not absolute in terms of physical condition. In winter it varies with weather and ground conditions and may, in turn, involve the adequacy of local food supplies. Probably there are logical reasons why some sites on the island are more heavily browsed than others.

These studies of the wolf and its prey have furnished convincing examples of the close linkage of behavioral and physical requirements in determining ecological status. The wolf defines its place in the community not only through its structure and physiology but also by acting like a wolf.

PROTECTION AND RESEARCH

As has been suggested, these investigations of the predation phenomenon would not have been possible in an area where the age structure of the moose herd was being altered by hunting or where the wolf was subject to attrition by man. In fact, it is quite likely that this wilderness national park is the only place in the world where adequate records of the kind necessary to our purpose could have been gathered.

The importance of the protection factor on Isle Royale has been emphasized by the fact that it has not been complete. In the first two winters of this work, Mech found that the large pack of wolves ignored the aircraft even at the closest possible working range—sometimes less than 100 feet. In the third winter it was noticed that the animals were using evasion tactics. During the following winters of 1962 and 1963, members of this pack were so obviously frightened by the aircraft that they frequently took refuge in heavy cover when approached within a quarter-mile. In March 1963, Shelton and pilot Donald E. Murray intercepted a strange plane in the park and reported it to FAA. It was found to be unlicensed and on that basis was grounded. In subsequent years wolves showed much greater tolerance, but we believe subjectively that they have never returned to the condition of nearly total unconcern that permitted such profitable observations in 1959-60. In 1971 another plane was observed at close range in the park as two groups of wolves were "buzzed" and scattered on the open ice.

For 2 years during Shelton's study, close observations of the large pack were almost impossible, evidently because the animals had been harassed and possibly shot at. This was costly to the research, and it also indicates the incompatibility of such activities as hunting with aesthetic utilization, including photography, in natural areas. Neither scientific nor recreational values of wilderness can be realized fully without effective protection against unnatural disruptions. These considerations are obviously applicable in the recurring controversy over ill-advised proposals to open national parks to hunting.

CONCLUSIONS

Isle Royale National Park exemplifies the scientific values of nearly any primitive area, and it has its own unique advantages as an outdoor research laboratory: The striking limitations of its biota represent a measure of simplification over what is commonly found elsewhere. As an island, it offers relatively "confined" populations of animals, which can be inventoried somewhat more easily than is possible on study plots in more extensive habitats. This ecosystem is sufficiently far north in latitude so that its extremes of summer and winter weather help reveal relationships that would be more obscure in areas farther south. The latter point was illustrated in the winter of 1971 when we recorded five cases in which moose attacked or confronted by the wolves went over precipices. Observed for the first time in the 13th winter, this also emphasizes the need for long-continued work. Considering the total complexity of what we are studying and have only begun to understand, it is evident that the end of profitable learning is not in sight. I believe strongly in my reply to a skeptical correspondent who inquired when we would be "satisfied" with our results and terminate our work: "If there are wolves and moose on Isle Royale in a century hence, I hope someone will be studying them."

REFERENCES

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