Biodiversity Bill Update

Washington Watch Biodiversity bill update

n its second year before Congress, tions, and organizations to collect determining what constitutes a signif- the biological diversity bill has and coordinate information on the icant reduction include losses of more I gained additional cosponsors in distribution, status, and characteris- than 10% of the geographic popula- both the House and Senate and con- tics of US biota for use in conserva- tions within any state of native spe- tinues to wind its way through the tidri and management. Information cies that have been found to be rare, legislative process. At press time, HR on communities, species, and popula- of special concern, or in significant 1268, introduced by James H. tions that are in significant decline, of decline. (Separate bills reauthorizing Scheuer (D—NY), had advanced be- special concern, and of outstanding the CEQ also direct the council to yond its predecessor (BioScience 38: importance is to be compiled by the prepare guidelines for consideration 455) by winning the approval of the center and published by the Council of biodiversity in EISs.) House Science and Technology Com- on Environmental Quality (CEQ). Gores bill contains international mittee and was awaiting hearings be- The center would also support addi- and agricultural sections not included fore the Merchant Marine and Fish- tional biological survey work. in Scheuers bill for jurisdictional rea- eries Committee. The Senate version The federal biodiversity strategy is sons. Representatives from agencies was newly introduced by Albert Gore to be developed by a new interagency that work internationally are directed Jr. (D—TN). committee working together with a to coordinate their international ac- The nearly identical bills aim to new scientific advisory committee. It is tions with the federal biodiversity create a national policy to conserve to include conservation strategies on a strategy. Conservation-related trea- biological diversity. Specifically, they regional ecosystem level, an approach ties, conventions, and educational call for creation of a National Center now being implemented in the Yellow- programs should be given priority. for Biological Diversity and Conser- stone and southern Appalachian areas. The Secretary of Agriculture is di- vation Research, establishment of a Agencies involved would prepare, im- rected to research such areas as alter- federal strategy for maintaining and plement, and evaluate their own bio- native crops, integrated pest manage- restoring biodiversity, consideration diversity plans that would include re- ment, and native grasses. of biodiversity in environmental im- gional considerations. Prospects for next year in both the pact statements (EISs), and appropri- Both bills further authorize federal House and Senate are uncertain. The ation of $45 million during three agencies to provide partnership House Merchant Marine and Fisher- fiscal years. grants for research, management, ies Committee, which has written The proposed national center is to training, and education to implement much wildlife conservation legisla- "set research priorities and provide the strategy. The National Science tion, must be convinced that a new leadership and coordination for the Foundation, which is to be a member approach is necessary to enhance past understanding and promotion of of the interagency committee, is to actions. Scheuers bill has 135 co- knowledge of the biota." Amend- "provide support for research that sponsors, but does not yet have a ments added by Scheuers natural re- integrates fundamental and applied majority within that committee. Gore sources subcommittee designate that science toward the conservation of has also assembled a bipartisan group the center be established within the biological diversity." of cosponsors. Smithsonian Institution, to ensure its The sections dealing with EISs are HR 1268 has been endorsed by scientific integrity, and in cooperation the most controversial parts of the AIBS and most of the biological pro- with the Environmental Protection bills. Although witnesses before fessional societies. Many environ- Agency (EPA), to tie the findings of Scheuers subcommittee agreed that mental groups have announced their the center to policy, in particular with loss of biodiversity is an environmen- support, but they have done little the EIS process. The center is to be a tal impact, it was also stated that lobbying so far. The extractive indus- semiautonomous unit of the Smith- explict directions for consideration of tries have begun to pay attention to sonian and not subsumed by any ex- biodiversity are lacking. New amend- the Scheuer bill but have not been isting body such as the Museum of ments to HR 1268 direct that the EPA vocal in their opposition. ^ National History. administrator, who is required by ex- The center would establish a coop- isting law to review EISs, shall find an erative network of agencies, institu- action proposed under an EIS to be David E. Blockstein was the 1987-1988 unsatisfactory if the action "is likely Congressional Science Fellow of the to result in a significant reduction of American Institute of Biological Sciences by David E. Blockstein biological diversity." The criteria for and the American Society of Zoologists. Purchased by the Forest Service November 1989 U.S. Department of Agriculture, 677 for official use Interpreting the Yellowstone Fires of 1988 Ecosystem responses and management implications

Norman L. Christensen, James K. Agee, Peter F. Brussard, Jay Hughes, Dennis H. Knight, G. Wayne Minshall, James M. Peek, Stephen J. Pyne, Frederick J. Swanson, Jack Ward Thomas, Stephen Wells, Stephen E. Williams, and Henry A. Wright

he fires that burned over the sphere Reserve by the Man and the Greater Yellowstone Area Biosphere Program of UNESCO pro- T (GYA) during the summer of The unpredictable is vide an ideal setting for establishing a 1988 were remarkable for their inten- the essence of the program of long-term research re- sity and scale—the largest fire com- lated to these fires. plex ever recorded for that area, the wilderness experience The federal government inaugu- rated its fire protection on public Norman L. Christensen is a professor in wildlands when the US Cavalry as- the Department of Botany, Duke Univer- biggest in the Northern Rockies dur- sumed administration of Yellowstone sity, Durham, NC 27706. James K. Agee is ing the last half century, and one of a National Park in 1886. In 1963, the a professor in the College of Forest Re- score of large-scale burns that have Leopold Committee (Leopold et al. sources, University of Washington, Seattle, dominated the fire history of the 1963), empaneled to review wildlife WA 98195. Peter F. Brussard is a professor United States during the past century management issues in the GYA, rec- in and the chairman of the Biology Depart- (Pyne 1982). The Yellowstone fires ommended reformation of the policy ment, University of Nevada, Reno, NV were likewise distinctive for the inten- of total fire suppression. The Park 89557. Jay Hughes is a professor in and sity and scale of public and media Service modified its fire policies in dean of the College of Forestry and Na- attention given them, for the great 1968 so that naturally ignited (light- tional Resources, Colorado State Univer- sity, Fort Collins, CO 80523. Dennis H. costs of their attempted suppression, ning) fires, burning within pre- Knight is a professor in the Department of and for the timely test they provided scribed guidelines, could be incorpo- Botany, University of Wyoming, Laramie, for the management philosophies, rated into the overall agenda of WY 82071. G. Wayne Minshall is a pro- policies, and programs of parks and national park management. fessor in the Department of Biology, Idaho wilderness areas. Also, the GYA is the The natural-fire management plans State University, Pocatello, ID 83209. site of Americas first national park administered in GYA after 1972 were James M. Peek is a professor in the College (1872) and its earliest national forest based on past experience and histori- of Forest Resources, Wildlife, and Range (1891), giving this event special sig- cal data indicating that fuel condi- Science, University of Idaho, Moscow, ID nificance from the standpoint of wil- tions confined large fires to old- 83843. Stephen J. Pyne is a professor in the derness management. growth pine or aging spruce-fir Department of History, Arizona State Uni- versity, West Campus, Phoenix, AZ Several factors make the 1988 fires forests. The sheer size of the Yellow- 85017. Frederick J. Swanson is a senior particularly important for wildland stone wilderness system was assumed research scientist in the USDA Forest Ser- ecological study. In particular, the to be adequate to contain natural vice, Forestry Sciences Laboratory, Corval- scale and heterogeneity of these fires fires. The experience from 1972 to lis, OR 97331. Stephen Wells is a professor provide unprecedented opportunities 1988 indicated, unlikely as it now in the Department of Geology, University to address a variety of landscape-level may seem, that the Yellowstone land- of New Mexico, Albuquerque, NM questions. Furthermore, the history of scape was comparatively nonflam- 87131. Jack Ward Thomas is a senior research and accumulated long-term mable (Romme and Despain page researcher for the USDA Forest Service in data on various components of GYA 695 and Schullery page 686 this is- La Grande, OR 97850. Stephen E. Wil- terrestrial and aquatic ecosystems will sue). liams is a professor in the Department of Plant, Soil, and Insect Sciences, University facilitate meaningful pre- and post- In November 1988, the Greater of Wyoming, Laramie, WY 82071. Henry fire comparisons. Finally, the commit- Yellowstone Coordinating Commit- A. Wright is Horn Professor and the chair- ment of much of the GYA to the tee (a committee of representatives person of the Department of Range and National Wilderness Preservation from the six national forests and two Wildlife Management, Texas Tech Univer- System and the designation of Yel- national parks that comprise the sity, Lubbock, TX 97409. lowstone National Park as a Bio- GYA) assembled a panel of scientists

678 BioScience Vol. 39 No. 10 representing a wide range of ecological disciplines to consider the ecological consequences of the 1988 fires. Specifically, the panel was asked to evaluate the ecological impacts and implications of the fires in relation to watersheds, fisheries, wildlife, vegetation, soils, and biological diversity; consider the need for interventions such as reseeding (to prevent erosion), reforestation, and supplementary feeding of ungulates; make recom- mendations for short- and long-term research programs; and consider alternatives and options for future fire management plans. This article sum- marizes that panels final report.l

The fires The 1988 fires burned a total of 11% (570,000 ha) of the GYA; however, approximately 45% (400,000 ha) of Yellowstone National Park burned (Schullery page 686 this issue). The fires followed a scenario typical for the region: prolonged drought, a rash of ignitions from dry lightning storms and human sources, a steady increase in fire size and intensity through July, and a near-fire-storm climax in late August and early September. From a historical perspective, fires in fuels such as those that typify much of the GYA tend to be either small or very Fire mosaic on Bunsen Peak. Foreground area was also burned. View is south from large. Throughout the Northern Mammoth area, June 1989. Photo: Ken Spencer. Rockies, a few fires and a few years account for most of the burned acreage (Pyne 1982). Very large fires have than by fuels. Virtually all forest age Historical data indicate that large burned under climatic conditions less and fuel categories burned. Although fires follow the development of old- severe than those experienced in the precipitation was above normal in growth forests on a cycle of 200-300 GYA during 1988, whereas other May and April, there were dramatic years. The specific years in which portions of the Northern Rockies that deficits in June (approximately 20% there were outbreaks of large-scale suffered similar conditions in 1988 of normal), July (approximately fire probably coincided with episodic escaped with far less burning. In 79%), and August (approximately droughts (Romme and Despain page 1910, some 3.25 million acres north- 10%), and 1988 ended as the driest 695 this issue). west of the GYA burned according to year on record. The summer drought, Can the scale of the 1988 fires be a chronology that was remarkably moreover, followed several years of considered natural? That is, could similar to that observed in 1988 (Pyne below-average annual precipitation. such extensive burning have occurred 1982, Schullery page 686 this issue). Abnormally strong and persistent without the influence of human activ- The behavior and extent of the southwesterly winds in July and Au- ity? Romme and Despain (page 695 1988 fires appear to have been influ- gust further dried fuels and caused the this issue) present convincing evi- enced more by drought and wind fires to spread at astounding rates. dence that similarly extensive fires The size of the fires assured that they took place on the Yellowstone pla- could not be stopped by small teau in the early eighteenth century. 1 The complete report of the Greater Yellow- stone Ecological Assessment Panel, commis- changes in microclimate, landforms, These fires occurred before the area sioned by the Greater Yellowstone Coordinat- or fuel beds or by standard suppres- was settled by people of European ing Committee of the National Park Service sion techniques. Nevertheless, these descent and, although little is known and USDA Forest Service to evaluate the eco- factors did influence fire behavior on about the impact of Native Ameri- logical impacts of the 1988 Yellowstone Fires, is available from the Division of Research, P.O. small spatial scales and contributed cans, they are thought not to have Box 168, Yellowstone National Park, WY significantly to the resulting mosaic of increased substantially the area 82190. burn intensities. burned by fires. Both historically and

November 1989 679 Upper left. The Wolf Lake Fire burning at night near Norris Geyser Basin, 8 August 1988. NPS photo by Jeff Henry. Lower left. After the fires, Yellowstone blooms again. Here, in early June, glacier lilies emerge from burned forest floor. Photo: Ken Spencer. Above. Some lodgepole pine cones opened after fire. The pines require fire to release their seeds. Photo: W. H. .041111 Romme.

context of a wilderness preserve, the ;-; acceptability of events such as the 1988 fires should be judged less on the basis of their causes and more on their consequences. Ecological impacts—knowns and unknowns Few if any ecological processes were or will be unaffected by the 1988 fires. At least three factors will likely cause considerable variation in ecosystem responses across the GYA landscape. First, variations in fuels, winds, and terrain resulted in heterogeneous patterns of burning, causing a wide variation in patterns of plant mortality, ash deposition, and soil heating. Second, postfire climatic patterns may influence the trajectories of many ecosystem processes. Third, the prefire and postfire patterns of the landscape mosaic that affect such processes as seed rain and animal behavior may influence ecosystem responses at specific localities, indepen- recently, some of the fires ignited by accumulated during the century of dent of the direct impacts of fire at people have burned areas that would fire suppression before 1972 in- those locations. Thus, we can only otherwise have been burned by fires creased the overall size of the 1988 phrase ecological forecasts in terms of started by lightning. fire complex (Romme and Despain probabilities and possibilities. The Even if the scale of the fires is page 695 and Schullery page 686 this heterogeneity and spatial scale of the considered to be natural, human ac- issue). GYA fires provide a unique opportu- tivities altered the pattern, and prob- It may not be useful to worry nity to determine how features such ably the specific extent, of the 1988 whether or not the fires were natural. as site variables, vegetation, climate, fires. People ignited fires responsible Avoiding the influence of people may and landscape mosaic interact to pro- for much more than half the burned no longer be a realistic or desirable duce specific responses to distur- area. There is debate whether fuel wilderness management goal. In the bance.

680 BioScience Vol. 39 No. 10 Geomorphic and hydrologic responses. Fire effects on hydrology and geomorphology will be determined by spatial variations in topography, bedrock geology, soil conditions, and vegetation, as well as temporal factors, such as short- and long-term patterns of precipitation. Removal of vegetation by fire influences the relative amounts of water lost from watersheds by evapotranspiration and surface and subsurface flow (Knight et al. 1985, Knight and Wallace page 700 this issue, Swanson 1981). In- creased runoff in heavily burned watersheds may result in higher peak discharges and accelerated erosion and sedimentation. Depending on factors such as fire intensity, slope, and soil characteristics, erosional processes may vary from subtle sheet erosion to catastrophic debris flows. The maximal impact of these processes could occur in the first few years (White and Wells 1981) or during several decades (Laird and Harvey 1986). The extent, variety, and heterogeneity of the 1988 fires provide an unprecedented opportunity for a gradient analysis of watershed responses to the variety of disturbance impacts. A study of patterns of fluvial and lacustrine sedimentation in connec- tion with studies of past fire history in the GYA would contribute a great deal to understanding the relationships between geomorphic processes and large-scale disturbance events.

Soils and belowground processes. The potential range of fire effects on soil properties is large and depends on Top. Ashy aftermath of crown fire, burned August—September 1988. This photo was prefire soil status, fire behavior, and taken in October 1988 and shows gray ash under trees. Bottom. Same site as above, in July 1989. The ground is now covered with Epilobium spp., fireweed. Photos: W. H. postfire events. Soil heating was high Romme. (nearly complete combustion of soil litter and humus layers) only in very localized situations associated with der way in the GYA will provide an atures, altered water chemistry, and fire storms or areas of high fuel accu- excellent basis for studies of the fac- abrupt changes in food quality. De- mulation (Shovic 1988). At these tors that determine the wide range of layed impacts may include increased sites, loss of organic matter and de- variation in fire effects on soil pro- turbidity and sediment loading and pression of microbial activity may ac- cesses. Because nitrogen often is lim- stream channel movement. Once tur- celerate erosion and diminish fertility. iting in GYA ecosystems (Fahey et al. bidity diminishes, conditions in most However, soil heating was light to 1985), the dynamics and cycling of aquatic ecosystems will probably en- moderate at most locations, and ash- this element deserve special attention. hance production of algae, inverte- fall and enhanced microbial activity Little is known regarding the influ- brates, and fish (Minshall et al. page probably will increase soil nutrient ence of fire on factors affecting soil 707 this issue). Long-term responses availability in the years immediately water chemistry in the GYA. of Yellowstone aquatic ecosystems after the fire (Fahey et al. 1985, Rai- will likely be closely allied with suc- son 1979, Woodmansee and Wallach Aquatic ecosystems. The immediate cession of surrounding forests (Cum- 1981). effects of fire on aquatic ecosystems mins et al. 1983, Minshall et al. 1983, Soil mapping projects already un- may include increased water temper- 1985). For example, recovery of for-

November 1989 681 Aerial photos show a burn mosaic that is sometimes called a halo; patches of black, burned forest surrounded by brown, less burned areas, and by green, untouched areas. This mosaic is created by spotting (i.e., fire spread by windblown embers). See Knight and Wallace page 700 this issue for the impact of such fire on landscape ecology. Photos: Ken Spencer. est cover will result in increased shad- nous cones of lodgepole pine) testify several decades (Knight and Wallace ing of streams and ponds and in de- to the long-term role of fire as an page 700 this issue). creased input of water and nutrients. evolutionary force on the GYA land- Fire effects on aquatic ecosystems scape. Thus, in most locations, re- Biodiversity. The importance of nat- probably will be greatest in small, growth will be rapid. ural disturbance processes such as fire more severely burned watersheds The total number of possible per- in the maintenance of landscape di- where thermal dispersion and chemi- mutations of successional pathways versity in the GYA has been thor- cal dilution of the water will be low- on the Yellowstone landscape is large. oughly documented (Houston 1973, est. As larger and larger watersheds Successional change at any location Patten 1963, Romme 1982, Romme are considered, greater percentages of will depend on such factors as fire and Despain page 695 this issue). No the area will not have burned, and the intensity and size, seed availability, species is known to be threatened as a larger catchment will diminish the abundance of sprouting growth consequence of the 1988 events, al- effects of the fire. forms, topographic and soil charac- though the relative abundances of The scale and heterogeneity of the teristics, preburn vegetation struc- species will probably change. The in- 1988 fires provide unique opportuni- ture, and climatic conditions in the creased spatial variability in environ- ties to develop models of the relation- next few years (Knight and Wallace ment and varied patterns of postfire ships among physical, chemical, and page 700 this issue, Romme and recovery will likely enrich species di- biotic features of aquatic systems and Knight 1981, Stahelin 1943). Land- versity (Taylor 1973). Decreased ex- patterns of disturbance. Studies scape diversity could be enhanced panses of contiguous old-age forest should include evaluation of sediment where the mosaic of successional pat- may result in the diminished abun- and nutrient pulses in both fluvial and terns is superimposed on the burn dance of interior forest species. How- lentic ecosystems. Studies to measure mosaic and as the process of succes- ever, species favoring edges and those the extent to which riparian and wet- sional change continues in the forests requiring two or more habitat types land features buffer stream-water that were not burned in 1988. can be expected to increase in abun- chemistry or act as nutrient filters will The effects of the fires on Yellow- dance (Franklin and Forman 1987). provide an ideal opportunity to inves- stone plant communities of the next An unwanted increase in diversity tigate the coupling of aquatic and few decades are expected to include: a of alien species, especially noxious terrestrial ecosystems. larger area in meadows and young weeds, could occur in some locations forests; aspen forest over a larger (Weaver and Woods 1985). Patterns of plant succession. The im- area, though probably still a small The preservation and management portance of past fires in shaping veg- portion of the park; sagebrush, be- of large mammals have been impor- etation patterns in the GYA is clear cause of its inability to resprout after tant issues in the GYA for decades (Romme and Despain page 695 this fire, will be less abundant in some (Chase 1986, Leopold et al. 1963). issue). Certain adaptations to fire seen areas for a decade or more; and more The direct and indirect effects of the in many native plants (e.g., the seroti- luxuriant herbaceous vegetation for 1988 fires on ungulate populations

682 BioScience Vol. 39 No. 10 are described by Singer (page 716 this Where the potential impacts on non- to whether or not the lands are man- issue). Although the combination of wilderness ecosystems are great, arti- aged for wilderness values. In lands drought, reduction of winter range by ficial interventions may be required. dedicated to commercial forestry or fire, and the harsh winter immediately Nevertheless, interventions that di- adjacent to human developments, following the fires may reduce ungu- minish wilderness values should be there may be a case for reforestation late populations, improved forage pursued only if a threat to nonwilder- activities. But in acknowledging fire quantity and quality should enhance ness ecosystems is clear and only if it as an integral process of natural eco- survival, growth, and fecundity dur- is reasonably certain that such inter- systems, we must also accept the nat- ing the next several years (Boyce in ventions will achieve their intended ural processes of postfire ecosystem press, Houston 1982, Singer page 716 goals. change as an integral part of wilder- this issue). ness landscapes. Nearly all native spe- It is tempting to suggest that the Feeding. Artificial feeding programs cies in these ecosystems are adapted Yellowstone landscape has been re- are expensive, alter animal behavior, to or depend on fire in one way or stored to some state that existed hun- facilitate spread of disease, and often another. The specific patterns that dreds of years ago. However, the data do not work. Worse, such programs emerge will depend on such factors as are insufficient to support such an focus attention on single components prefire ecosystem structure and spe- assertion. We can state with confi- of ecosystems, especially the charis- cies composition, specific site envi- dence that events similar to those of matic megafauna (e.g., bison, elk, and ronments, local patterns of fire sever- 1988 have altered GYA ecosystems in bears), and reflect an unwillingness to ity, and unpredictable postfire events the past (Romme and Despain page recognize that natural processes in including year-to-year variations in 695 this issue). Still, the Yellowstone wilderness ecosystems often have re- climate. This combination of varia- of 2072 will not be the same as that of sults that in human terms appear to bles was responsible for much of the 1872, just as the landscape of 1872 be cruel. Wilderness preserves should variety of the Yellowstone landscape was unique compared with previous not be managed as either zoos or before the 1988 fires and will un- times. Even without human influences museums, item by item. Rather, the doubtedly contribute to the future (of which there have been many; goal is to preserve the complexity of heterogeneity of that landscape. It Haines 1977), Yellowstone land- dynamic interactions among the vari- would be difficult, if not impossible, scapes would continue to change if ous ecosystem components that are to devise a reforestation strategy that for no other reason than climatic essential to its functioning. could replicate this diversity. Further- changes and the continued evolution, more, artificial planting probably immigration, emigration, and even Soil stabilization. The erosion pro- would alter the distribution of tree possible extinction of plant and ani- cesses that shape wilderness land- genotypes. mal species. Big changes occurred in scapes do not operate at constant 1988, and it is safe to assume that rates, but rather they occur in epi- Research philosophy such changes will occur again in the sodes associated with natural distur- future. Indeed, such change is the sine bances such as fire. The 1988 fires If prudence argues against aggressive qua non of wilderness. probably will alter runoff and in- intervention, it also argues against a crease erosion in many locations on doctrinaire strategy of laissez-faire. It Postfire management the Yellowstone landscape. Within would be reckless and irresponsible to interventions the context of wilderness, such commit irrevocably to a particular changes are expected and in some management strategy when the scale Artificial feeding of ungulates (e.g., cases even desirable. The geomorpho- of the disturbance involves half the deer), seeding with short-lived alien logic and hydrologic consequences of park wilderness and the future path- herbs in areas subject to erosion, and the Yellowstone fires certainly are le- ways of landscape change are known artificial reforestation activities to gitimate concerns for nonwilderness only within broad parameters. If our speed ecosystem succession are among ecosystems downstream. However, state of knowledge argues against the postfire interventions thus far pro- the potential impacts currently do not emergency intervention, our state of posed by some groups. However, there appear to be sufficient to warrant an ignorance argues for a program of are compelling arguments for a light emergency soil stabilization program, aggressive data collection and evalua- hand in coping with the unique scene if indeed one were possible across tion. A monitoring network adequate created by the fires of 1988. such a large area. Remedial measures to gauge postfire changes simply must The borders of wilderness preserves such as seeding with alien species may be present to compare actual develop- have for the most part been defined temporarily stabilize soils, but in the ments with forecasts and thereby on the basis of political and economic long term they could actually acceler- make informed judgments. In order criteria, with little or no regard for ate erosion by interfering with estab- to thrive, a monitoring program must natural divides or ecological bound- lishment of native plants and encour- complement an active agenda of sci- aries that regulate natural processes. aging their replacement with noxious entific research. The consequences are reciprocal: an weeds. Because of the location and scale of event outside wilderness preserves the 1988 fires, tremendous public and can affect ecosystems within and Reforestation. Other proposed reme- scientific interest now centers on the events within wilderness ecosystems diations, notably artificial reforesta- GYA. The 1988 fires provide the op- can reach outside the preserves. tion, should be evaluated according portunity to study disturbance at the

November 1989 683 landscape scale, in an area that has to withdraw suppression practices not been heavily influenced by hu- and permit naturally ignited fires to mans and in a context that should We have learned burn freely. Since then, the philosoph- facilitate the establishment of long- enough to know ical issues have blurred and the oper- term studies. The challenge is to focus ational problems have multiplied. It is these resources on important research that wilderness not enough to withdraw aggressive issues and to organize a program that landscapes are suppression from wild areas. Rather, can follow through with long-term fire management must blend various observations that are essential to in- not predestined forms of suppression with various terpreting the ecosystem consequences forms of prescribed fire. of the fires. Success requires substan- to achieve a Fire programs must necessarily be tial and rapid agency commitment. particular structure predicated on a state of knowledge The three essential ingredients of a that is fallible and a capacity for research program for events such as environmental control that is imper- the GYA fires are an ecosystem ap- fect. It is unwise for fire agencies to proach to provide for conceptual in- sume more knowledge than is actually claim perfect knowledge, and it is tegration and operational coordina- available and policies assume consen- unfair for the public to demand it of tion of many research projects, a sus where there is conflict. them. It is not necessary that all spe- landscape or geographic context for Fires on the scale of those in Yel- cific outcomes of fire programs be individual projects, and provision for lowstone demand decisions, but they known in advance, only that a pro- long-term studies and monitoring of also distort and magnify inevitable gram be able to specify an acceptable key system characteristics and pro- flaws in protocols for making such range of outcomes and identify the cesses. The ecosystem approach will decisions. When fires of a magnitude means by which fire can ac sieve facilitate coordination of projects, such as those observed in 1988 occur them. which increases opportunity for ser- in a place (such as Yellowstone) that Fire management on public lands endipity and synergism and increases can attract major media attention, now operates under a pluralistic pol- the efficiency of investment in basic they take on the character of a celeb- icy that allows in principle for an environmental monitoring (e.g., cli- rity scandal. equilibrium between fire use and fire mate and streamflow) needed to sup- Humans often can intervene with control. Within the decision to support such studies. Understanding and fire in ways that they cannot intervene press fire, a number of responses are recognizing the geographic context of with volcanoes or hurricanes. We can possible. The Yellowstone fires do not research sites is necessary to extrapo- apply or withdraw ignition, and we so much challenge the wisdom of that late observations over larger areas can reshape the environment within policy as they demand the support based on information such as the which a fire may burn. Both fire sup- necessary to implement it. Fire man- burn severity maps. pression and prescription, however, agement plans must include, in the The 1988 fires will have ecological pivot on a paradox. The only way to context of detailed written prescrip- consequences that extend over a cen- eliminate wildland fire is to eliminate tions, guidelines for monitoring and tury or more. Therefore, it is impor- wildlands. To extirpate fire com- evaluating natural prescribed fires. tant to establish research programs pletely from a wildland ecosystem is Presuppression plans to guide major that deal with the long-term aspects to remove an essential component of fire-control operations are essential. of these processes. that wilderness. Similarly, to alter the Care must be taken that interagency fuels in a significant way is to change agreements to harmonize procedures Management implications the character of the wildlands that are for accepting fires along administra- being protected. The strategy has thus tive borders do not disguise different Federal wilderness preserves are ad- evolved to substitute various kinds of operational criteria for distinguishing ministered within a matrix of legisla- controlled or prescribed fire for wild- between prescribed and wildfires. tive mandates, agency directives and fire. Designating naturally ignited Also, the acceptability of naturally policies, and locally prescribed poli- fires as prescribed fires (or as confined ignited fires must be conditioned by cies and protocol. Elements of this suppression fires) belongs within this the constraints of preserve design and matrix both proscribe and prescribe spectrum of management options. size. Fires that might be considered certain actions, but they do not dic- When, following the Leopold Re- natural by various criteria will not tate a single, monolithic scheme in all port (1963) and the Wilderness Act necessarily be acceptable in the con- preserves. Management ambiguities (1964), the dilemma of fire protection text of such constraints. often result. Fire management pro- in wilderness and parks became an It is clear that the assortment of fire grams within individual wilderness object of intense scrutiny, many ob- management plans in the GYA was preserves do not follow as a syllogism servers believed that wilderness fire inadequate for the 1988 fires. How- from national policies and hand- management involved merely the res- ever, it is unlikely that any fire plan books. The need to allow for local toration of a natural process into a could have foreseen an event of this discretion and to accommodate local natural environment. The required magnitude or coped with a complex situations perpetuates rather than re- means were conceptual conviction of fires that, by the time the decision moves these ambiguities and uncer- and political will. In its purest expres- to suppress was made, was uncontrol- tainties. Yet too often guidelines as- sion, a wilderness fire program sought lable (Schullery page 686 this issue).

684 BioScience Vol. 39 No. 10 Once a fire becomes large, suppres- ideals into management objectives 32-35,61-63. and develop and install monitoring Minshall, G. W., J. T. Brock, and J. D. Varley. sion is often possible only when the 1989. Wildfires and Yellowstones stream weather changes. procedures adequate to measure ecosystems. BioScience 39: 707-715. Increasingly, wilderness manage- progress toward those objectives. Minshall, G. W., K. W. Cummins, R. C. Peter- ment has emphasized the preservation Most important, they must actively sen, C. E. Cushing, D. A. Bruns, J. R. Sedell, of natural processes rather than sim- support research programs that re- and R. L. Vannote. 1985. Developments in stream ecosystem theory. Can. J. Fish. ply the preservation of natural fea- duce the state of uncertainty regard- Aquat. Sci. 42: 1045-1055. tures, objects, or scenes. We now rec- ing the natural phenomena they are Minshall, G. W., R. C. Petersen, K. W. Cum- ognize the subversive consequences of charged with managing. mins, T. L. Bott, J. R. Sedell, C. E. Cushing, halting natural succession and the fu- While accepting that chance exists and R. L. Vannote. 1983. Interbiome com- in the natural world and that manage- parison of stream ecosystem dynamics. Ecol. tility of trying to recreate a former Monogr. 53: 1-25. scene over large areas. Even if knowl- ment is required even when knowledge Patten, D. T. 1963. Vegetational pattern in re- edge of former circumstances was is incomplete, managers must also rec- lation to environments in the Madison Range, perfect, which it is not, social, cli- ognize that it is possible to narrow the Montana. Ecol. Monogr. 33: 375-406. matic, and environmental conditions choice of purposes, to contract the Pyne, S. J. 1982. Fire in America: A Cultural History of Wildland and Rural Fire. Prince- have changed so much that an ideal range of ambiguity surrounding objec- ton University Press, Princeton, NJ. replication is unlikely. The landscape tives, and to shrink the domain of Raison, R. 1979. Modification of the soil envi- embodies chance as well as mecha- ignorance. Many unknowns can be ronment by vegetation fires, with particular nism; there are those who would ar- reduced to uncertainties, and uncer- reference to nitrogen transformations; a re- gue that chance is itself a value, that tainties to probabilities. view. Plant Soil 51: 73-108. Romme, W. H. 1982. Fire and landscape diver- the unpredictable is the essence of the sity in subalpine forests of Yellowstone Na- wilderness experience. References cited tional Park. Ecol. Monogr. 52: 199-221. Knowledge of the causes and con- Romme, W. H., and D. G. Despain. 1989. sequences of natural processes such as Boyce, M. S. In press. Effects of the 1988 fires Historical perspective on the Yellowstone fire is rudimentary, but we have on ungulates in Yellowstone National Park. fires of 1988. BioScience 39: 695-699. Proc. Tall Timbers Fire Ecol. Con/. Romme, W. H., and D. H. Knight. 1981. Fire learned enough to know that wilder- Chase, A. 1986. Playing God in Yellowstone: frequency and subalpine forest succession ness landscapes are not predestined to The Destruction of Americas First National along a topographic gradient in Wyoming. achieve some particular structure or Park. Atlantic Monthly Press, New York. Ecology 62: 319-326. configuration if we simply remove Cummins, K. W., J. R. Sedell, F. J. Swanson, Schullery, P. 1989. The fires and fire policy. human influences. A great variety of G. W. Minshall, S. G. Fisher, C. E. Cushing, BioScience 39: 686-694. R. C. Petersen, and R. L. Vannote. 1983. Shovic, H. F. 1988. Postfire soil research. Re- future natural landscape configura- Organic matter budgets for stream ecosys- port to the Greater Yellowstone Postfire Eco- tions is possible, although all config- tems: problems in their evaluation. Pages logical Assessment Workshop, Mammoth, urations are not equally likely nor 299-353 in J. R. Barnes and G. W. Minshall, Wyoming, 17 November 1988. eds. Stream Ecology: Application and Test- Singer, F. J., W. Schreier, J. Oppenheim, and equally desirable. Given the restricted ing of General Ecological Theory. Plenum size and arbitrarily defined bound- E. 0. Garten. 1989. Drought, fires, and large Press, New York. mammals. BioScience 39: 716-722. aries of most wilderness preserves, Fahey, T. J., J. B. Yavitt, J. A. Pearson, and Stahelin, P. 1943. Factors influencing the nat- some possible configurations may be D. H. Knight. 1985. The nitrogen cycle in ural restocking of high altitude burns by far less desirable than others. We can- lodgepole pine ecosystems. Biogeochemistry coniferous trees in the central Rocky Moun- 1: 257-275. tains. Ecology 24: 19-30. not escape the need to articulate Franklin, J. F., and R. T. T. Forman. 1987. clearly the range of landscape config- Swanson, F. J. 1981. Fire and geomorphic pro- Creating landscape patterns by forest cut- cesses. Pages 421-444 in H. A. Mooney, urations that is acceptable within the ting: ecological consequences and principles. T. M. Bonnicksen, N. L. Christensen, J. E. constraints of the design and intent of Landscape Ecol. 1: 5-18. Lotan, and W. A. Reiners, eds. Fire Regimes particular wilderness preserves. Haines, A. 1977. The Yellowstone Story. Col- and Ecosystem Properties. USDA Forest Ser- It is easy to promulgate objectives orado Associated Universities Press, Boulder. vice General Technology Report WO-26, Houston, D. B. 1973. Wildfires in northern Washington, DC. to protect and preserve a particular Yellowstone National Park. Ecology 54: Taylor, D. L. 1973. Some ecological implica- scene in wilderness preserves, but de- 1111-1117. tions of forest fire control in Yellowstone veloping analogous objectives to pre- 1982. The Northern Yellowstone Elk. National Park, Wyoming. Ecology 54: serve and protect particular natural Macmillan, New York. 1394-1396. processes have proven considerably Knight, D. H., T. J. Fahey, and S. W. Running. Weaver, T., and B. Woods. 1985. The exotic 1985. Water and nutrient outflow from con- flora of Glacier National Park: a preliminary more difficult. It is clear that, just as trasting lodgepole pine forests in Wyoming. atlas. MSU Biology Report No. 37. Montana human presence in and around wil- Ecol. Monogr. 55: 29-48. State University, Bozeman. derness landscapes is inescapable, hu- Knight, D. H., and L. L. Wallace. 1989. The White, W. D., and S. G. Wells. 1981. Geomor- man intervention and manipulation Yellowstone fires: issues in landscape ecol- phic effects of La Mesa fire. Pages 73-90 in will be necessary to preserve those ogy. BioScience 39: 700-706. La Mesa Fire Symposium. Los Alamos Na- Laird, J. R., and M. D. Harvey. 1986. Com- tional Laboratory LA-9236-NERP, Los processes. The questions that the next plex response of a chaparral drainage basin Alamos, CA. generation of natural area managers to fire. Pages 165-184 in Drainage Basin Woodmansee, R. G., and L. S. Wallach. 1981. must address are not whether manip- Sediment Delivery. International Association Effects of fire regimes on biogeochemical ulations is desirable, but what kind of of Hydrological Sciences Publication 159, cycles. Pages 379-400 in H. A. Mooney, manipulation is acceptable? By what Washington, DC. T. M. Bonnicksen, N. L. Christensen, J. E. Leopold, A. S., S. A. Cain, C. M. Cottam, I. N. Lotan, and W. A. Reiners, eds. Fire Regimes means? For what purposes? On what Gabrielson, and T. L. Kimball. 1963. The and Ecosystem Properties. USDA Forest Ser- scale? According to what social and Leopold Committee report: wildlife manage- vice General Technical Report WO-26, political processes? They must rewrite ment in the national parks. Am. For. 69: Washington, DC.

November 1989 685 The Fires and Fire Policy

The drama of the 1988 Yellowstone fires generated a review of national policy

Paul Schullery

he Greater Yellowstone Area For the NPS, allowing natural fires (GYA) fires of 1988 were, in to burn was only part of a broad T the words of National Park It is difficult to management redirection. The initial Service (NPS) publications, the most separate scientific impetus for redirection was the 1963 significant ecological event in the his- Leopold Report, named for A. tory of the national parks (NPS interest and aesthetic Starker Leopold, chairman of a com- 1988). Their political consequences wonder from mittee of ecologists appointed by the may be as far-reaching as their eco- secretary of the interior to consider logical consequences. consternation at the wildlife management issues in the The fires have been characterized in parks (Leopold et al. 1963). The com- many ways, from natural catastrophe political effects mittee proposed that the highest goal to ecological wonder and from policy of the parks was to maintain "biotic blunder to scientific bonanza. They associations" that were found in the have generated a national dialogue nities in most North American set- park area when first visited by Euro- that goes beyond the issue of fire in tings. Fire was a tool for land man- peans. Where such associations could national parks and forests to more agement among many early European not be maintained or recreated, a fundamental questions about the settlers as well, for clearing land and "reasonable illusion of primitive management of public lands. encouraging the growth of preferred America" could at least be kept in The term Yellowstone fires is an plants and animals (Pyne 1982, place. unfortunate oversimplification. The Wright and Bailey 1982). This charge, which became NPS fires occurred in the GYA, 4.8 million Early in this century, the course of policy in 1968, was fraught with ha of mostly public land in Wyoming, federal fire management was largely a complications. No national park is Montana, and Idaho. The GYA con- reaction to some huge and economi- ecologically isolated from its sur- sists of Yellowstone (YNP) and Grand cally disastrous forest fires. For exam- roundings; little is known about the Teton National Parks (GTNP), two ple, in 1910, fires burned 3 million precise ecological condition of any national wildlife refuges, and six na- acres in Idaho and Montana, mostly park at the time it was first visited by tional forests, as well as state and on government land, destroying sev- Europeans; maintaining biotic associ- privately owned land (GYCC 1987). eral towns and killing dozens of fire ations requires maintaining dynamic fighters. Therefore, fire management natural systems in which change is was regarded simply as fire suppres- Fire management history unavoidable, thus precluding the sion (Pyne 1982). In the 1940s, how- maintenance of any specific ecological Ecologists have long recognized that ever, the US Forest Service (USFS) state; natural systems cannot change fire was a major factor shaping land- began to use fire as a silvicultural tool without affecting the relative abun- scapes in prehistoric America. Fires in some southeastern forests (Kilgore dance of various elements of the bi- set by lightning or American Indians 1976). In the 1950s, the NPS started otic communities; and elements of the controlled plant and animal commu- experimenting with controlled burns pre-European setting, such as Ameri- in Everglades National Park. Similar can Indians, may no longer be pre- experimentation was conducted in Se- sent, nor may their effects be known Paul Schullery is a technical writer and quoia National Park in the early editor with the Research Division of the or replicable. The Leopold Commit- National Park Service in Yellowstone Na- 1960s, and by 1972 there were 12 tee and many subsequent observers tional Park, WY 82190. He specializes in NPS areas in which some lightning- recognized these complications, but natural resource and resource manage- ignited fires were allowed to burn respecting parks for their ecological ment topics. (Kilgore 1985, Parsons 1981). processes was widely recogized as a

686 BioScience Vol. 39 No. 10 useful ideal around which management policies have evolved (Houston 1971). YNP has been a pivotal and controversial testing ground for the Leopold Report, and the fires of 1988 may have provided the sternest test of the practicality of maintaining biotic associations. Of management agencies in the GYA, the NPS has recently pursued a natural fire policy most aggressively. From the establishment of the park in 1872 until 1971, all fires were fought as well as personnel and equipment permitted (Houston 1973, Taylor 1974). Fire suppression, however, was not consistently effective in the parks extensive forests until the arrival of aerial fire fighting technology after World War II (Romme and Despain page 695 this issue and Schullery and Despain 1989). In 1972, 15% of the acreage of YNP (136,000 ha), all in backcountry areas, were designated as natural fire zones. Any lightning- caused fires starting there were to be allowed to burn, if they did not threaten human life, property, cultural sites, or specific natural features of unusual value, such as threatened or endangered species (Despain and Sell- ers 1977, NPS 1987). Although the policy also allowed park managers to intentionally ignite fires, a procedure used freely in some other parks, it was not considered useful by Yellowstone managers because climate, rather than available ignition sources, seems to be the driving force behind fires effect on the Yellowstone landscape (Romme and Despain page 695 this issue). Dur- ing the next several years, most of the park was added to the natural fire zones (NPS 1987). GTNP initiated a similar plan in 1972. Scenes like this one were common on the TV evening news. The fire is part of a back The national forests surrounding burn set just inside the northeast corner of Yellowstone National Park as part of the fire Yellowstone Park also developed nat- suppression efforts on the Storm Creek Fire, Labor Day weekend, 1988. NPS photo by ural fire management plans, and coop- Jim Peaco. erative agreements that were in place by 1988 allowed managers in a park or forest to "accept" a fire that was Newcomers to the fire dialogues it is reclassified as a wildfire. But a approaching their boundary from an- may find the language puzzling. In fire wildfire is not necessarily one that is other unit (USDA/USDI 1988). There management, a prescribed fire is one out of control; it is merely a fire that were substantial differences in the that, whether it was set by humans or must be suppressed. Thus, almost plans of the parks and forests, espe- lightning, is burning within the pre- counterintuitively, a wildfire is often a cially in their arbitrarily prescribed scriptions set by managers for fires human-set fire and a prescribed fire is limits on the size to which a fire might that will be allowed to burn, some- generally caused by lightning. be allowed to grow; NPS plans acco- times for months. In YNP, virtually all In its first 16 years (1972-1987), modated large fires, whereas USFS prescribed fires are lightning-caused. A the Yellowstone Fire Management plans were more restrictive because wildfire is a fire that does not meet the Plan was widely considered a success those areas are being managed to meet agencys prescriptions. A prescribed within the agency and among conser- a different mandate. fire can behave in such a manner that vation groups. In that period, 235

November 1989 687 Left. What burned in the Greater Yellowstone Area. Key to map: red, crown fire in dense forest; green, mixed dense vegetation; orange, crown fire in medium-density forest; turquoise, mixed medium-density vegetation; yellow, crown fire in sparse forest; light green, mixed sparse vegetation; dark green, nontimber burn. Right. Major GYA fires by ignition source. Key to map: pink, human-caused; green, originating on US Forest Service land (natural); orange, originating on National Park Service land (natural); blue, lakes. a. Fan Fire. b. North Fork Fire. c. Hellroaring Fire. d. Storm Creek Fire. e. Human-caused burn, set as part of Storm Creek Fire control efforts. f. Clover Mist Fire. g. Mink Fire. h. Huck Fire. i. Snake River Complex Fire. Maps produced by the Geographic Information Systems Division, Yellowstone National Park. Data gathered and analyzed by Don Despain, NPS. fires were permitted to burn a total of Dendrochronological research sug- USDI 1988). The GYA climate is typ- 13,662 ha (NPS 1987). Only 15 of gested that the process by which Yel- ified by dry summers; most precipita- the fires exceeded 40 ha, and all the lowstones mosaic of vegetation types tion falls as snow (Dirks and Martner fires extinguished naturally. The larg- was maintained did not operate con- 1982). But in the period from 1982 to est single fire burned 2960 ha. Public sistently, year by year. Instead, GYA 1987, the GYA experienced an aver- education programs by the NPS forests appeared to alternate between age of about 200% of normal precip- stressed the values of restoring fire to short periods—a year or a few itation in July (NPS 1988). Although its place in wilderness processes, and years—of large fires and long inter- much of the west suffered a serious public acceptance of the program was vals (200 to 400 years) of relatively drought in those years, naturally perceived as high. small fires each year (Romme 1982). caused fires burned less than 400 ha The small size of most fires indicated By 1988, it was clear that the GYA in the park during those six years. that in a typical summer, though there had in the past experienced very large Fire managers began to anticipate the will be hundreds of lightning strikes, fires and also that extensive areas of continuation of wet summers, and few will result in fires of any size. The the park were entering their most April and May of 1988 seemed to lodgepole pine (Pinus contorta) forests burnable stage. Roughly one-third of herald yet another wet season. that dominate much of the GYA (and the parks forests were 250 to 350 But in the spring, a high-pressure constitute 77% of YNP forests) do not years old (Romme and Despain page zone formed and settled over the burn easily and have little undergrowth 695 this issue). The advanced age of northern Rockies as the jet stream until old age (Brown and Bevins 1986, many forests seems to have been a sent incoming storms north into Can- Romme and Despain page 695 this much more significant factor in the ada. Fuel grew progressively drier, issue). Only the oldest forests—those accumulated fuel loads than any ef- and frequent thunderstorms provided with substantial fuel in downed trees fects of human fire suppression since lightning but no rain. The summer and undergrowth—burn readily. Dur- the establishment of YNP in 1872 was the driest in the parks recorded ing 1972-1987, fires were regularly (Schullery and Despain 1989). history. In August and September, a observed to skip over, pass around, or series of six dry cold fronts crossed stop at the edge of young forests.1 The 1988 fire season the GYA, bringing winds that routinely gusted 60-100 km/hr (USDA/ Don Despain, 1989, personal communication. The GYA entered a mild drought late USDI 1988). Within this extraordi- Research Division, National Park Service, Yel- in 1987 and was considered to be in a nary climatic context, the GYA fires lowstone National Park, WY. severe drought by mid-May (USDA/ ignited and grew.

688 BioScience Vol. 39 No. 10 By the standards of the previous 16 years, the 1988 fire season began routinely. In late May and early June, 11 of 20 early season fires extinguished naturally, and the rest exhibited no unusual behavior. NPS and USFS fire specialists monitored the fires and a variety of recognized danger indices, including moisture content of fuels, lightning- and man-caused fire risks, energy release component (the heat given off by a fire dictates how it will be fought and what equipment must be on hand), and spread component (a computation of probable speed of a fires movement based on conditions). The first three weeks of July are the critical period in the early stages of the fire season. Managers watched fire conditions with growing concern, then alarm, even though the fires were not yet especially large. On 15 July, for example, only approximately 3440 ha had been burned in the entire GYA. On 21 July, when NPS personnel decided to declare all fires wildfires and suppress them, 6800 ha had burned. By then the fires were national news, and on 27 July the secretary of the interior visited the park and reaffirmed the decision to fight all current and new fires there (Figure 1). Satellite image of Wyoming-Montana-Idaho-Utah-Colorado area on 7 September 1988 But by then continued dry weather shows major smoke plumes from Greater Yellowstone Area fires spreading across and high winds had pushed the park Wyoming, while smaller fires burned in Montana, Idaho, and Utah. Photo: NASA/ across the threshhold for large fires. Ames Research Center. Within a week of the decision to suppress all fires, the perimeter acreage of YNP fires exceeded 40,000 ha. were human-caused wildfires fought fighters participated during the course By 15 August, the perimeter total was from the start (Figure 2). of the fire season, as many as 9500 at approximately 100,000 ha. By 1 Sep- The scale of the fires shocked many one time. On many occasions, there tember, the GYA total was 340,800 people. On the much-publicized were not enough fire fighters or ha, with 220,000 of that in the park. "Black Saturday," 20 August, wind- equipment to attack all fires fully. Fire These preliminary estimates were of- driven flames burned 64,000 ha. fighters from land management agen- ten based solely on helicopter over- Smoke and particles from the GYA cies were aided by personnel from the flights; detailed mapping of burn ar- fires traveled east across North Amer- Wyoming National Guard and the eas is still under way. All burn area ica, sometimes obscuring the sun for Air National Guard and the US figures that follow in this article are hundreds of kilometers. Some of the Army, Air Force, Marine Corps, and based on aerial mapping with a reso- fires deliberately set by fire fighters to Navy. More than 100 aircraft and lution of 80 ha; later-generation maps deprive an oncoming fire of fuel were 100 fire trucks from several states are expected to reduce most burn area larger than most natural fires of the also were used. The total cost was figures as the burn mosaics are plot- previous 16 years. approximately $120 million. ted more precisely. Fire behavior was characterized as There were 248 recorded fire starts Fighting the fires "unprecedented" by many sources, in the GYA in 1988, 31 of which were but it would be more precise to say allowed to burn as prescribed fires. On 23 July, GYA managers created that fire in the GYA had never been Twenty-eight of the 31 were in YNP. the Greater Yellowstone Area Com- experienced on such a grand scale. Seven fires were responsible for more mand, located in West Yellowstone, Previous fires in North America had than 95% of the area burned (Maps, Montana, to coordinate fire-fighting burned as much or more acreage and page 688). Five of those seven origi- operations in the GYA. As the fires had behaved as spectacularly, but not nated outside YNP, and three of those grew, resources from other agencies in the presence of what was probably five, including the largest fire of all and regions were drawn into the ef- the largest single fire suppression ef- (the North Fork Fire, 201,610 ha), fort. Approximately 25,000 fire fort in American history or in the face

November 1989 689 night as they often do; fire fighters bulldozer lines were also constructed. could make no more progress at night After September, precipitation qui- than in the day (USDA/USDI 1988). eted the fires, and fire crews worked Attempts to project maximal possible to minimize the effects of these distur- size of a given fire were repeatedly bances. However, the turning of the foiled.2 soil may result in increased erosion, Yellowstone attractions added un- heightened hospitality to nonnative usual hazards. All fire camps had to plants, or simply an enduring scar. be kept clean to avoid conflicts with Removal of trees creates an artificial grizzly bears (Ursos arctos) and other corridor that will remain apparent scavengers, and some fire fighters indefinitely (Figure 4). were injured when they inhaled fumes Fire-fighting activities can displace from burning mineral deposits near wildlife (as when a camp is built in a hot springs. Fire fighting focused meadow where animals graze) or at- most effectively on protection of detract it (as when food is brought into veloped areas. Although the fire- bear country). Collisions with fire- fighting effort may not have signifi- fighting vehicles killed 108 large cantly reduced the total acreage mammals, but such collision mortal- burned by the large fires, fire fighters ity is typical of YNP in other sum- were successful in protecting build- mers. Fire trucks and other vehicles ings. In a series of dramatic stands, often drove off roadways, some as far Satellite image of the North Fork fire several park developments and sur- as three miles; these scars may last 30 approaching the town of West Yellow- rounding communities were saved by or more years. Aircraft logged more stone, MT, on 2 September 1988 (top is north). Note numerous spot fires appear- such techniques as intensive fuel re- than 18,000 hours of flight time in ing along the leading edge of the west- duction along their edges and the YNP alone (Figure 6). The noise of bound fire. The river is the Madison, soaking of buildings with water and the aircraft, especially at helicopter which leaves the park just north of West fire retardant (Figure 3). landing strips, displaced animals, but Yellowstone and eventually becomes one The most famous episode was the no formal monitoring was under- of three rivers that join at Three Forks, Old Faithful fire storm of 7 Septem- taken due to the emergency situation. MT, to form the Missouri River. Notice ber, when the eastbound North Fork Approximately 5.3 million liters of that the west boundary of Yellowstone fire, driven by winds in excess of 100 fire retardant were dropped on fires in National Park is clearly delineated south km/hr, jumped over the entire 400- YNP. This retardant may have short- of West Yellowstone. Clearcuts in structure development, the Firehole term fertilizing effects on vegetation; Targhee National Forest show differences of land use directions among various ele- River, and the Upper Geyser Basin. but at least two small fish kills, ap- ments of the Greater Yellowstone Area. Twenty-two small buildings, mostly proximately 100 fish each, resulted Photo: NASA/Ames Research Center. cabins, were destroyed, and several from retardant drops in streams. others were damaged; these losses Thirty-eight million liters of water were considered light under the cir- were dipped or pumped from various of such advanced knowledge of fire cumstances. A total of 67 structures GYA streams and lakes for dumping behavior. were destroyed in the GYA, and an- on fires, drawing down some ponds Fires advanced as much as 16 km in other 12 were damaged. and disturbing natural processes in a day. Wind-driven flames routinely There were numerous, mostly mi- many others (Figure 5). jumped formidable barriers, such as nor, injuries to fire fighters. However, the Grand Canyon of the Yellowstone one fire fighter was killed by a falling Assessing ecological impacts River, park roads, and even the broad snag in October operations on the expanse of the Upper Geyser Basin. Clover-Mist fire in Shoshone Na- Aerial mapping of GYA fires was When winds carried embers ahead of tional Forest, and a pilot was killed completed in September 1989 (GYP- the fires front, spot fires were created when his light plane crashed near FRAC-BAST 1988). According to this as much as 2.5 km in advance of the Jackson, Wyoming. preliminary coarse-resolution map- main fire. These spot fires compli- ping, fires affected more than 560,000 cated efforts to fight fires head-on; fire Fire-suppression impact ha-395,570 ha of which were in fighters were in danger of becoming YNP (Table 1). Fires burned with trapped between the main fire and its The impact of the fire-suppression varying intensity and effect. In the outlying spot fires. efforts will be visible for many years. GYA, 61% of the burned area expe- Fast-moving fires were impossible Dozens of camps and helicopter land- rienced canopy burn (trunk, limbs, to stop with conventional hand- or ing sites were scattered through the and needles or leaves of trees burned), bulldozer-dug trenches (fire lines). GYA. Approximately 1071 km of and 34% experienced surface burn Fire jumped most of the hundreds of hand-dug fire lines and 220 km of (fire crept along the ground and did kilometers of fire lines that it ap- not burn the canopy, leaving many proached. Because of the extreme vol- 2Richard Rothermel, 1989, personal communi- trees partly or completely unburned). atility of fuels and low relative hu- cation. Intermountain Research Station, USDA An additional 32,000 ha of meadows midity, fires did not stop moving at Forest Service, Missoula, MT. and sage grasslands were burned

690 BioScience Vol. 39 No. 10 Figure 1. The North Fork Fires smoke was visible at Old Faithful on 25 July 1988. Photo: Jim Peaco, National Park Service.

(GYPFRAC-BAST 1988). prised those of us conditioned by Immediate effects on threatened The result of the varying burns is a Smokey the Bear and Bambi. Con- and endangered animals were light. mosaic of burned, unburned, and par- trary to "common knowledge" about No peregrine falcons (Falco peregri- tially burned areas. There is little uni- the destructiveness of fires, relatively nus), currently the subject of reintro- formity of pattern or scale across the few large mammals died (Singer et al. duction work in Yellowstone Park, mosaic; fires were influenced by many page 716 this issue). Most large- were known killed by the fires. Five factors, including wind, slope, fuel mammal mortality was the result of bald eagle (Haligeetus leucocephalus) availability and condition, and hu- smoke inhalation, though many of nests were destroyed, but no eagles midity, so that in some areas the the carcasses were burned afterward. were known lost (McEneaney 1989). mosaic is quite fine (with burned and Large mammals were frequently ob- Two grizzly bears are also thought to unburned patches only a few feet or served grazing or bedded down in have perished in the fires.3 yards across), whereas in other areas meadows near burning forests; actual it is coarse (with all the vegetation for flight was rare, and only necessary on dozens of square hectares uniformly days when fires made major runs 3R. Knight, 1989, personal communication. burned). (Singer et al. page 716 this issue, Interagency Grizzly Bear Study Team, Forestry The ability of Yellowstones large Singer and Schullery 1989, Mills Sciences Laboratory, Montana State Univer- mammals to survive the fires sur- 1989). sity, Bozeman, MT. Table 1. Greater Yellowstone areas burned by major fires (in ha). Grand Teton Yellowstone Bridger-Teton Custer Gallatin Shoshone Targhee Fire National Park National Park National Forest National Forest National Forest National Forest National Forest Total Clover-Mist 80,310 47,520 127,830 Fan 8360 8360 Hellroaring 7850 18,840 26,690 Huck 1080 10,250 33,150 44,480 Mink Creek 16,620 29,910 46,530 North Fork 196,090 1000 4520 201,610 Snake River 68,810 68,810 Storm Creek 7280 12,280 18,440 38,000 Total 1080 395,570 63,060 12,280 38,280 47,520 4520 562,310 All figures are preliminary, based on coarse resolution (finest unit of measurement 80 ha) aerial mapping. Figures from GYPFRAC-BAST 1988. A few minor and peripheral fires are not included in totals.

November 1989 691 Figure 2. The North Fork Fire moving along the Madison River in Yellowstone National Park in August 1988. Photo: Jeff Henry, National Park Service.

Many small animals died in the fire some animals, but there are rhetorical the course of the next 200-400 years, or attendant smoke (Mills 1989). The traps in such pronouncements. If the present various plants and animals fires will result in shifts of relative goal of the park is to protect biotic with opportunities that will never be abundance of various species of birds, associations and processes rather the same from year to year. A species mammals, and insects, but there is no than promote growth of favored ani- advantaged now may be disadvan- evidence to suggest that any individ- mals, then terms like "good" and taged in 40 years. Recent paleoeco- ual species will be in danger of extinc- "beneficial" are of limited value. The logical research indicates that very tion because of the fires.4 Predators parks ecological processes will, over nearly the same mammalian fauna took advantage of the loss of cover after the fires to harvest many small mammals. McEneaney (1989) observed more than 40 ferruginous hawks (Buteo regalis), a species un- common in YNP, hunting openly near Hayden Valley, and he proposed that they had followed smoke col- umns from outside the park to the good hunting grounds. The fortunes of wildlife in the fires exemplify the complications of public perspectives on the fires. Many observers have spoken reassuringly about the fires as "beneficial" to wildlife, and "good" for the forests and other plant communities. It is true that the fires will in some ways benefit

4R. Renkin, 1989, personal communication. Figure 3. Fire-retardant foam was used on buildings, in this case a residence at Research Division, National Park Service, Yel- Mammoth Hot Springs, 10 September 1988. Most buildings were adequately protected lowstone National Park, WY. by such techniques. Photo: Jim Peaco, National Park Service.

692 BioScience Vol. 39 No. 10 fires (USDAJUSDI 1989). Because this process could not be completed in time for the 1989 fire season, Secretary of the Interior Manuel Lujan and Secre- tary of Agriculture Clayton Yeutter directed their managers to suppress all fires in 1989. Ecological effects and research opportunities were also examined and projected (Christensen et al. page xxx this issue, Mills 1989, MSU 1988). The scientific community has recognized a unique opportunity to study the effects of ecosystem-wide fires in a relatively pristine setting, but funding problems may cause much of the opportunity to be lost. The public response will be hardest to measure. Although the principles behind NPS and USFS fire policies were and still may be fairly well re- Figure 4. Bulldozers were used to cut fire lines, in this case in Gallatin National Forest ceived in the specialized scientific and near the northeast entrance to Yellowstone National Park and to Cooke City, MT. Fire fighters are moving through a bulldozer-cleared area where all trees have been removed for a width of at least 8 bulldozer blades. Bulldozer lines proved no more effective than hand-dug lines at holding fast-moving fires and left scars that will remain indefinitely. Photo: Jim Peaco, National Park Service. occurred in Yellowstone 1700 years lished postfire procedures. These eval- ago as today,5 since which time the uations dealt with many aspects of GYA has probably experienced sev- each fires suppression effort, includ- eral major fire events. This continuity ing bureaucratic procedures, decision of species presence suggests that the making, and actual mechanical imple- 1988 fires should not significantly af- mentation of decisions. During the fect mammalian diversity. fire season, many controversial decisions were made, and the review pro- Responses to the fires cess brought out various operational shortcomings. In the long run, the The GYA fires may have closely rep- enduring legacy of these review teams licated a natural event (Christensen et may not be in their findings on any al. page 678 and Romme and Despain specific procedural issue but in the page 695 this issue), but they repli- broader view—the fires as a GYA cated it in a day when such natural phenomenon, needing improved co- events are extremely inconvenient for ordination on an ecosystem-wide society. They were, in many respects, level (GYCC 1989). a hardship to the people who live, On 28 September 1988, the secre- work, or visit the region, as well as to taries of agriculture and interior created the local commerce. They were the a Fire Management Policy Review source of considerable outrage and Team to evaluate the fire policies of the more than a little tragedy. It has NPS and the USFS wilderness areas. proven difficult for the public to sep- This interagency team included repre- arate the scientific interest and aes- sentatives of the NPS, the USFS, the US thetic wonder of their ecological ef- Fish and Wildlife Service, the Bureau of fects from the consternation of their Land Management, the Bureau of In- political and economic effects. dian Affairs, and the National Associa- The largest fires were subjected to tion of State Foresters. While reaf- Figure 5. Helicopters routinely dipped formal operational reviews by intera- firming the principles and fundamental water from Greater Yellowstone Area gency teams, in keeping with estab- importance of allowing fire a role in streams and ponds to use in fire fighting. these public lands, it recommended that Shown here is the North Fork fire along SE. Hadly, 1989, personal communication. Re- fire management plans of various parks the Madison River, Yellowstone National search Division, National Park Service, Yellow- and forests must be "strengthened" in Park, August 1988. Photo: Jeff Henry, stone National Park, WY. some ways aimed at better control of National Park Service.

November 1989 693 Leopold, A. S., S. A. Cain, C. M. Cottam, I. N. Gabrielson, and T. L. Kimball. 1963. Wild- life management in the national parks. Trans. N. Am. Wildl. Nat. Resour. Con/. 24: 28-45. McEneaney, T. 1989. The Yellowstone wildfires of 1988, what really happened to the bird life? Winging It 1: 1-2,7. Mills, S., ed. 1989. The Greater Yellowstone Postfire Assessment. Greater Yellowstone Coordinating Committee, Yellowstone Na- tional Park, WY. Montana State University (MSU). 1988. Greater Yellowstone Fire Impact and Recov- ery Research Workshop Report. 14-17 Oc- tober 1988. Montana State University, Boz- eman, MT. National Park Service (NPS). 1987. Wildland fire management plan for Yellowstone Na- tional Park. NPS, Yellowstone National Park, WY. 1988. Yellowstone fires: 1988. Special supplement to Yellowstone Today, Nov. 1988. Yellowstone Association, Yellowstone National Park, WY. Mountain ranges are blanketed by smoke from the Mink Creek fire in the Absaroka Parsons, D. J. 1981. The role of fire manage- Mountains, southern Greater Yellowstone Area, 19 August 1988. Photo: Jim Peaco, ment in maintaining natural ecosystems. National Park Service. Pages 469-488 in E. A. Mooney, T. M. Bonnickson, N. L. Christensen, J. E. Lotan and W. A. Reiners, eds. Fire Regimes and Ecosystem Properties. USDA/USFS General conservation communities, they were vegetative types in the Northern Rocky Technical Report No. WO-26, Washington, unknown to the public in the summer Mountains. Research Note INT-358. USDA/ DC. USFS Intermountain Research Station, Og- Pyne, S. J. 1982. Fire in America: A Cultural of 1988. Even President Reagan pro- den, UT. fessed ignorance of the policies. History of Wildland and Rural Fire. Prince- Christensen, N. L., J. K. Agee, P. F. Brussard, ton University Press, Princeton, NJ. Many GYA managers and residents J. Hughes, D. K. Knight, G. W. Minshall, J. Romme, W. H. 1982. Fire and landscape diver- feared that media coverage of the fires M. Peek, S. J. Pyne, F. J. Swanson, J. W. sity in subalpine forests of Yellowstone Na- gave a sensationalist view of the fires Thomas, S. Wells, S. E. Williams, and H. A. tional Park. Ecol. Monogr. 52: 199-221. Wright. 1989. Interpreting the Yellowstone Romme, W. H., and D. G. Despain. 1989. and convinced the public that YNP fires of 1988. BioScience 39: 678-685. was destroyed, and analysis of media Historical perspective on the Yellowstone Despain, D. G., and R. E. Sellers. 1977. Natu- fires of 1988. BioScience 39: 695-699. coverage of the fires has suggested that ral fires in Yellowstone National Park. West. Schullery, P., and D. G. Despain. 1989. Pre- reporters did misrepresent the situa- Wildlands 4: 20-24. scribed burning in Yellowstone National tion (Smith 1989a,b). The multiple Dirks, R. A., and B. E. Martner. 1982. The Park: a doubtful proposition. West. Wild- filters of agency public affairs offices, climate of Yellowstone and Grand Teton lands 15: 30-34. National Parks. USDI/NPS Occasional Paper Singer, F. J., and P. Schullery. 1989. Yellow- regional chambers of commerce, and No. 6, Washington, DC. stone wildlife: populations in process. West. print and electronic media seem in Greater Yellowstone Coordinating Committee Wildlands 15: 18-22. some cases to have stood between the (GYCC). 1987. An aggregation of national Singer, F. J., W. Schreier, J. Oppenheim, and public and an accurate picture of the park and national forest management plans. E. 0. Garten. 1989. Drought, fires, and large fires and their ecological significance. USDA/USDI, Billings, MT. mammals. BioScience 39: 716-722. . 1989. Coordination of management Smith, C. 1989a. Reporters, news sources, ac- The impact of the GYA fires on public review, 1988 Greater Yellowstone fire situa- curacy, and the Yellowstone forest fires. Pa- consciousness about wildland man- tion. USDA/USDI, Billings, MT. per presented at the annual meeting of the agement and the ecology of fire ap- Greater Yellowstone Post-Fire Resource As- International Communications Association, pears to be considerable, and thereby sessment Committee, Burned Area Survey San Francisco, May 1989. Team (GYPFRAC-BAST). 1988. Preliminary 19896. Flames, firefighters and moon- the 1988 fires may have continued scapes: network television pictures of the effects on the formulation of public burned area survey of Yellowstone National Park and adjoining national forests. NPS/ Yellowstone forest fires. Paper presented at land fire policies for many years. USFS/NASA/Montana State University, Yel- the third annual Visual Communications lowstone National Park, WY. Conference, Park City, UT, 26 June 1989. Taylor, D. L. 1974. Forest fires in Yellowstone Houston, D. B. 1971. Ecosystems of national Acknowledgments Science National Park. Journal of Forest History 18: parks. 172: 648-651. 69-77. Sandra Sloat and John D. Varley of 1973. Wildfires in northern Yellow- USDA/USDI. 1988. Greater Yellowstone Area stone National Park. Ecology 54: 1111- fires of 1988: phase II report. Interagency the Research Division of Yellowstone 1117. Task Force, USFS Region 2, Denver, CO and National Park provided helpful com- Kilgore, B. M. 1976. From fire control to fire NPS Rocky Mountain Region, Lakewood, ments on the manuscript. management: an ecological basis for policies. CO. Trans. N. Am. Wildl. Nat. Resour. Con/. 41: 1989. Final report of the Fire Manage- 477-493. ment Policy Review Team. USDA/USDI, References cited 1985. The role of fire in wilderness: a Washington, DC. state-of-knowledge review. Intermountain Wright, H. A., and A. W. Bailey. 1982. Fire Brown, J. K., and C. D. Bevins. 1986. Surface Research Station General Technical Report Ecology, United States and Southern Can- fuels loadings and predicted fire behavior for INT-182, Ogden, UT. ada. John Wiley Sons, New York.

694 BioScience Vol. 39 No. 10 Historical Perspective on the Yellowstone Fires of 1988 A reconstruction of prehistoric fire history reveals that comparable fires occurred in the early 1700s

William H. Romme and Don G. Despain

aintaining an ecosystem scarred trees were not present in shaped primarily by natu- many areas, we consider our esti- M ral geological and ecologi- The extensive fires of mated dates of fires during the last cal processes is a primary goal in 1988 should not be 300 years to be reliable only within Yellowstone National Park (YNP) one to three years. Therefore, we pre- (Houston 1971). Thus, one important viewed as an sent the amount of area burned in question about the fires of 1988 is 10-year intervals. whether they were really natural: Did abnormal event We also reconstructed the forest they behave as they would have if mosaics that probably covered our Europeans had never entered the study area at various times during the area? The park had a policy of com- of the park, lies at an elevation of last 250 years. First we classified the plete fire suppression from 1872 to 2400 m and contains dry, infertile stages of postfire succession after can- 1972, so past fire control may have habitats on rhyolite substrates as well opy fires on the Yellowstone Plateau led to abnormal fuel conditions and as more mesic and fertile habitats on by sampling a sequence of stands therefore to abnormal fire spread and andesite and lake-bottom substrates burned at various times during the behavior in 1988 (Dodge 1972, (Despain in press). last 400 years (Figure 2, bottom). We Kilgore and Taylor 1979). In this From color, low-level aerial photo- then drew a map showing the stand article, we compare the fires of 1988 graphs we constructed a map of forest age (number of years since the last with fires during the previous 350 patches. We then located in the field stand-replacing fire) and successional years. We use both information con- each patch that was more than 5 ha, stage in 1985 of each forest patch. tained in park files and results of our and we collected increment cores For each patch, we calculated its tree-ring research on the prehistoric (small, nondestructive samples of tree stand age in 1735 and estimated its fire history. rings from which tree age can be successional stage by using the ob- estimated) from 5 to 10 dominant Fire History lodgepole pine trees, as well as from cross sections from any fire-scarred We reconstructed the history of fires trees. Large patches (more than 100 in a 129,600-hectare study area lo- ha) were sampled in at least two cated on the subalpine plateaus in areas. south-central YNP (Figure 1). This In the lab, we determined the dates area, comprising approximately 15% of past fires from the fire-scarred sections using dendrochronological meth- William H. Romme is an associate profes- ods (Arno and Sneck 1977). Many sor of biology at Fort Lewis College, patches contained no fire-scarred Durango, CO 81301. His current work trees; in these patches we determined includes analysis of fire spread in relation the date of the last fire from the ages of to landscape heterogeneity and vegeta- the dominant lodgepole pine trees. tional responses to the 1988 Yellowstone fires. Don G. Despain is a research biolo- Finally, we used our map generated gist at Yellowstone National Park, WY from the aerial photographs to deter- 82190. He works on vegetation mapping, mine the areas burned (Arno and fire ecology, and plant-animal interac- Sneck 1977, Heinselman 1973). Be- tions. His current projects include inter- cause rings are extremely narrow in Figure 1. Subalpine study area in south- actions of aspen fire and elk browsing. most fire-scarred trees and fire- central Yellowstone National Park.

November 1989 695 ▪

served relationship between age and this century (NPS 1988).1 main from previously fire-killed trees. stage. With this approach, we recon- The forest mosaic provided a fuels Crown fires propagate only in ex- structed mosaics of stand age and complex in which fires could burn tremely windy conditions. This suc- probable successional stage for our intensely over large areas under these cessional stage lasts from approxi- study area at 20-year intervals from weather conditions. Our reconstruc- mately 40 to 150 years postfire. 1735 to 1985. This work was an tions indicate that it may have been Even-aged closed canopies of extension of an earlier study (Romme nearly 300 years since the Yellow- lodgepole pines with a developing un- 1982, Romme and Knight 1982). stone landscape had been composed derstory of Engelmann spruce (Picea The 1988 fires burned more area of such a flammable mix of forest engelmannii) and subalpine fir (Abies than was burned in any previous 10- stands. Figure 2 (top) shows the per- lasiocarpa) are classified as LP2. This year period within our study area cent of our study area covered by stage lasts from approximately 150 to (Figure 2, bottom). The large extent different forest successional stages 300 years after a fire. Fuels on the of burn probably was due to weather (Figure 3) at various times during the forest floor are sparse to moderate, conditions in 1988; the structure of last 250 years. and flammability begins to increase in the forest mosaic in 1988, which was Lodgepole pine (Pinus contorta) is the later portions of this stage. Fi- a product of successional events dur- the most common tree in YNP, and nally, LP3 stands have pine, fir, and ing the last 250-300 years; and the Despain (in press) has characterized spruce of all ages. This stage persists effects of fire suppression in the twen- stands there by their age and state of until the next stand-replacing fire. tieth century. development. Recently burned for- Young spruce, fir, and dead fuels are The summer of 1988 was the driest ests, until the time of canopy closure dense enough to propagate crown since recordkeeping began in YNP in (approximately 40 years), are classi- fires under dry conditions even with- 1886. April and May had been wetter fied as LPO. In these forests, large logs out wind. than average, but precipitation in do not burn easily and live fuels are The earliest successional stages, June, July, and August was 20%, usually too green, and small dead (LPO, LP1, and the initial period of 79%, and 10% of normal, respec- fuels too sparse, to carry fire readily. LP2) which are comparatively less tively (NPS 1988). By late July, the Stands dominated by densely clus- flammable than the older stages (De- moisture content was as low as 2-3% tered, young, even-aged lodgepole spain in press, Despain and Sellers in dry herbs and dead twigs and 7% pines are classified as LP1. Fuels on 1977), were the most common suc- in larger dead woody fuels. These dry the forest floor are generally sparse, cessional stages in our study area fuels, combined with high tempera- although some large, rotten logs re- from the mid 1700s through the tures and extraordinary winds pro- 1800s. The more flammable older duced by a series of dry high-pressure 1 R. Rothermel, 1989, personal communica- stages have dominated since the early systems, created some of the most tion. Intermountain Research Station, USDA 1900s. severe burning conditions observed in Forest Service, Missoula, MT. Several extensive fires occurred in our study area between 1690 and 0 1710 and again between 1730 and 1750 (Figure 2, bottom). Although I Complete I Natural more recently some fires have oc- I Suppression I Fire curred in every decade, there were no 0 very large fires, comparable to those U IPolicy I Program of the early 1700s, until 1988. Note 0 that during most of this period there ro 0 ...... ...... LP2 were no Europeans in the region to 14 40 - ...... a Np. influence the fire regime. Native ffj 30 - Americans had a significant influence d . • 14 20 - LP1 on fire frequency in many parts of North America (Barrett 1980, Pyne io LP 0 1982), but, although their role in high-elevation forests of the Yellow- 20 stone region is not well understood, they probably had only a minor influ- 10 ence there. Existing data (Taylor 111-r-111-r 1964) suggest that Native Americans /4 20 40 60 80 1 20 40 60 80 1 20 40 60 80 used the warmer and more productive 1700 1800 1900 landscapes at lower elevations more extensively than the high plateaus. Figure 2. Top: Percent of the study area burned by stand-replacing fires in each decade Moreover, even if Indians were numerous in our subalpine study area, from 1690 to 1988. Bottom: Percent of the 129,600-hectare subalpine study area covered by each successional stage from 1735 to 1985. The area covered by meadows, their major effect on fire history prob- water, and other constant features of the landscape are not included in the figure ably was in igniting fires, and ignition (Romme 1982). The reconstructions extend back only to 1735 because extensive fires sources appear to be far less impor- around 1700 destroyed the evidence necessary to reconstruct earlier landscape mosaics. tant than weather and fuel conditions

696 BioScience Vol. 39 No. 10 in determining fire-return interval in hiked into an inaccessible area, the agement policies that permitted some this ecosystem. fire either had gone out or had grown lightning-caused fires to burn without to such a size that it could not be interference in backcountry areas Why fire activity had been low extinguished with the hand tools (Despain and Sellers 1977). There- available. fore, the period of consistent fire ex- We suggest that one important reason By the mid-1970s, Yellowstone, clusion in most of Yellowstone Na- for the low level of fire activity during Grand Teton National Park, and sev- tional Park, from the mid 1940s until the last 250 years was that the forest eral of the adjacent National Forest the mid-1970s, spanned approxi- mosaic was composed largely of early Wilderness Areas had new fire man- mately 30 years. Even during the to middle successional stages, so it had relatively low flammability. a b Lightning probably ignited fires every summer, but, due to unfavorable fuels complexes, fires were unable to spread over large areas. It is also possible that there simply were no years from 1735 to 1987 with weather conditions as dry and windy as 1988. We cannot tell, because tree rings indicate moisture and temperature conditions, but not wind. Fires as extensive as those of 1988 probably could have been supported by the vegetation in any year after approximately 1930 (Figure 2, top). We suggest that they did not occur until 1988 because of summer weather conditions and human fire control efforts. How important was suppression? Park records reveal that lightning ignitions have occurred every summer Even without suppression, most of C these ignitions fail to spread. They occur either in a fuels complex that cannot support fire spread or during a period of wet weather. From 1972 through 1987, 235 lightning-caused fires (an average of 15 per year) were allowed to burn without interference in Yellowstone National Park.2 All but 15 of these fires (94%) burned less than 40 ha and only 8 (3.4%) were larger than 400 ha. Moreover, only in 5 of these 16 years did the total area burned in the park equal more than 40 ha, and in only 2 years did it exceed 4000 ha. Organized fire suppression efforts in YNP began in 1886. These early efforts probably were fairly effective along roads and major trails, but they probably had little effect in remote areas on the high plateaus until after World War II, when new fire-fighting Figure 3. Forest successional stages in Yellowstone National Park (Despain 1989). See methods and technologies became Taylor (1969) for additional discussion on flammability. a. LPO: recently burned stands widely available. Written accounts in up to the time of canopy closure (0-40 years postfire). b. LP1: stands dominated by park records from before the 1940s dense, young, even-aged lodgepole pine (Pinus contorta var. latifolia) (40-150 years suggest that often by the time a crew postfire). c. LP2: even-aged, closed canopy of lodgepole pine stands with a developing understory of lodgepole pine, subalpine fir (Abies lasiocarpa), and Engelmann spruce 2Unpublished fire records on file at Yellow- (Picea engelmannii) (150-300 years postfire). d. LP3: all-aged stands of pine, fir, and stone National Park, WY. spruce, which persist until the next stand-replacing fire.

November 1989 697 effective suppression period, fires pole pine forests, covering thousands large fires would have created patches burned hundreds of hectares in some of hectares, that originated after past of less flammable early successional years-1946, 1949, 1953, 1960, fires (e.g., in 1703); such stands ap- stages, the more continuous landscape 1961, and 1966 (Taylor 1973). parently develop only after severe in turn may have allowed the fires in fires that kill all aboveground bio- 1988 to burn a larger total area than if The effect of fire suppression mass and consume much of the or- fires had burned without interference ganic matter of the forest floor, as during the effective suppression pe- How then did these 30 or so years of occurred in 1988. Second, the differ- riod. The actual effectiveness of such attempted fire exclusion influence fire ences in fire behavior in 1988 and in hypothetical fire barriers is difficult to behavior in 1988? Our data (Figure 2) uncontrolled lightning-caused fires in assess, however, because in August indicate that the principal effect of fire 1976, 1979, and 1981 were largely and September 1988 the fires were suppression was to delay the onset of a quantitative rather than qualitative. jumping over and burning through ar- major fire event, which probably was These earlier, uncontrolled fires were eas up to 1600 ha that had burned just inevitable given the nature of the fuels as intense or nearly so and spread 10-50 years earlier. Finally, our land- complex that had developed since the almost as rapidly as the 1988 fires, scape reconstructions (Figure 2, top) last extensive fires in the 1700s. Large but they maintained high intensities do not show an abrupt change in the fires might have burned during the six and rates of spread for much shorter landscape mosaic corresponding to the dry summers from 1946 to 1966 had times. Third, 30 years of fire exclu- onset of fire suppression; rather they all lightning-ignited fires not been sup- sion does not appear to be long show a continuation of successional pressed. However, these fires probably enough to create abnormal fuel con- dynamics that were initiated almost would not have been as extensive as ditions in these forests characterized 300 years earlier. the fires of 1988 because the weather by centuries-long intervals between We conclude, therefore, that the conditions were less severe. If some of fires. The accumulations of dead fires of 1988 should not be viewed as the area that burned in 1988 had woody fuels observed before the 1988 an abnormal event. Some of the fires burned in those previous years, the fires are typical of late successional were unnatural in terms of ignition 1988 fires might have been smaller. lodgepole pine stands (Brown 1975). source (three of the eight major fire From this perspective, the fires of Indeed, early explorers in Yellow- complexes were caused by people, the late twentieth century were com- stone described dense tangles of dead and these fires were responsible for parable, in total area burned, to the and fallen trees (e.g., Strong 1875, roughly half of the total area burned). fires of the late seventeenth and early Langford 1905), long before fire sup- However, numerous lightning igni- eighteenth centuries. Stand-replacing pression could have produced abnor- tions occurred in the vicinity of the fires burned 34% of our study area mal changes in fuels. human-caused fires in late July and during the 50-year period from 1690 Although the fuel conditions within August of 1988. If the human-caused to 1739, and 26% of our study area any individual stand probably were fires had been eliminated and these during the 49-year period from 1940 not abnormal, the extent and continu- lightning fires had been allowed to to 1988 (Figure 4). ity of flammable old-growth stands burn without interference, they might An important difference is that may have been greater in 1988 than have burned a comparable area, al- nearly all of the area burned in the they would have been with no previ- though the spatial distribution would most recent half-century was burned ous fire suppression. Because earlier have been different. in one year rather than being spread out over a few major fire years. What may be the ecological effects? In- Complete creased landscape homogeneity could 40 Suppression result if a large, single burn was uni- form (Turner 1988). However, in Policy 1886 - 1972 many areas, the 1988 burns were 30 - quite patchy due to spotting behavior Z and variation in fuel conditions and topography. This patchiness, combined with differential rates of succes- ga 20 sion, will maintain a considerable level of heterogeneity in most of our study area. 10 Were the 1988 fires abnormal? There are three indications that fire 1640- 1690- 1740- 1790- 1840- 1890- 1940- behavior, in terms of heat release, 1689 1739 1789 1839 1889 1939 1988 flame height, and rate of spread, was similar in 1988 and in the 1700s. Figure 4. Percent of the area within the study area that burned during each half-century First, we identified even-aged lodge- interval from 1640 to 1988.

698 BioScience Vol. 39 No. 10 In terms of total area burned and elk and bison of Yellowstone Na- parks. Science 172: 648-651. tional Park, whose trails facilitated Kilgore, B. M., and D. Taylor. 1979. Fire fire severity, the 1988 fires evidently history of a sequoia-mixed conifer forest. were similar to those around 1700. our travel in remote and otherwise Ecology 60: 129-142. Past human actions, mainly fire sup- inaccessible areas. Langford, N. P. 1905. The Discovery of Yel- pression, had some influence on the lowstone Park, 1870. J. E. Haynes, St. Paul, size and behavior of the fires in 1988, References cited MN. but these large fires were the result Pyne, S. J. 1982. Fire in America: A Cultural History of Wildland and Rural Fire. Prince- primarily of drought and wind condi- Arno, S. F., and K. M. Sneck. 1977. A method for determining fire history in coniferous ton University Press, Princeton, NJ. tions, as well as of normal succes- forests of the mountain west. US Forest National Park Service (NPS). 1988. The Yel- sional dynamics following the last Service General Technical Report INT-42, lowstone fires: a primer on the 1988 fire major fires approximately 280 years Ogden, UT. season. Unpublished report, Yellowstone ago. Barrett, S. W. 1980. Indian fires in the preset- National Park, WY. tlement forests of western Montana. Pages Romme, W. H. 1982. Fire and landscape diver- 35-41 in Proceedings of the Fire History sity in subalpine forests of Yellowstone Na- Acknowledgments Workshop, Tucson, AZ. USDA Forest Ser- tional Park. Ecol. Monogr. 52: 199-221. vice General Technical Report RM-81, Fort Romme, W. H., and D. H. Knight. 1982. This research was supported by NSF Collins, CO. Landscape diversity: the concept applied to Grant BSR 8408181 (RUI) and by Brown, J. K. 1975. Fire cycles and community Yellowstone Park. BioScience 32: 664-670. dynamics in lodgepole pine forests. Pages Strong, W. E. 1968. A trip to the Yellowstone grants from the University of Wyo- 429-456 in D. M. Baumgartner, ed. Man- National Park in July, August, and Septem- ming-National Park Service Research agement of Lodgepole Pine Ecosystems. ber, 1875. University of Oklahoma Press, Center. We thank the following peo- Symposium proceedings. Washington State Norman. ple, many of them students at Fort University Cooperative Extension Service, Taylor, D. C. 1964. Preliminary archaeological Lewis College, for their assistance in Pullman. investigations in Yellowstone National Park. Despain, D. G. In press. Yellowstones Vegeta- Unpublished report. Yellowstone National the field: G. Evans, B. Fedders, J. tion: The Consequences of History and En- Park Research Library, WY. Fedders, K. France, D. Frey, M. vironment. Roberts Rinehart, New York. Taylor, D. L. 1969. Biotic succession of lodge- Gregg, J. Hood, B. Le Maire, R. Lev- Despain, D. G., and R. E. Sellers. 1977. Natu- pole pine forest of fire origin in Yellowstone inson, D. McGuinn, J. OHara, M. ral fire in Yellowstone National Park. West. National Park. PhD dissertation, University OHara, A. Tanner, L. Van Dusen, K. Wildlands 4: 20-24. of Wyoming, Laramie. White, P. White, and J. Whipple. J. Dodge, M. 1972. Forest fuel accumulation-a 1973. Some ecological implications of growing problem. Science 177: 139-142. forest fire control in Yellowstone National OHara and J. Hood also helped with Heinselman, M. L. 1973. Fire in the virgin Park, Wyoming. Ecology 54: 1394-1396. laboratory analyses, and D. H. forests of the Boundary Waters Canoe Area, Turner, M. G., ed. 1987. Landscape Heteroge- Knight reviewed a draft of the maim- Minnesota. Quat. Res. 3: 329-382. neity and Disturbance. Springer-Verlag, Ber- script. Finally, we acknowledge the Houston, D. B. 1971. Ecosystems of national lin, FRG.

See the Great Yellowstone Fires and Help in their Recovery

A spectacular 24" X 36" full-color poster captures the Your poster, reference key, and educational guide will be drama of one of the greatest ecological events of our shipped in a heavy, protective tube. Please allow 6-8 weeks time. for delivery. For additional gift shipments, please note on a separate sheet and attach to your order. Photographed by satellite during the height of fire activity, this dynamic image allows you to identify the Quantity @ $12.95 each $ major fires and see almost 11/2 million acres consumed Postage and handling @ $2.00 per poster $ by their force. The poster was developed by the American Forestry NAME Association and EOSAT Corp. in cooperation with the ADDRESS USDA Forest Service. It includes a number-coded key of CITY STATE ZIP the fires and major landmarks, including Old Faithful. Payment method: And to help you learn more about the role of fire in the life cycle of a forest, a colorful fire ecology education Check, payable to The American Forestry Association guide is also included. This dramatic poster is available for just $12.95 plus Visa ^ Mastercard $2.00 postage and handling-the reference key and fire Card number Exp. date ecology education guide are free with your purchase. Profits from poster sales will be contributed to the Authorized signature Forest Services Greater Yellowstone Area Recovery Fund and used for fire recovery and rehabilitation. Return to: The American Forestry Association, P.O. Box 2000, Washington, DC 20013 The Yellowstone Fires: Issues in Landscape Ecology A landscape perspective is necessary in resolving the difficulties of natural area management

Dennis H. Knight and Linda L. Wallace

ire policy is only one of many have such disturbances as fires and controversies that have charac- insect outbreaks. F terized the management of Yel- New opportunities Some would argue that national lowstone National Park (YNP). Some exist in Yellowstone parks are too small, or too strongly people opposed establishment of the affected by humans, to allow distur- park in the first place, fearing that it to understand effects bances such as fire to occur uncon- would detract from economic devel- of disturbances tolled (Bonnicksen 1988, 1989). Al- opment. Later there were arguments though true for many natural areas, about whether or not predator con- Yellowstone is one of the largest US trol was necessary to increase the parks. If it is too small, the 1988 abundance of big game. Currently the of that, area."1 fires—the most significant distur- reintroduction of wolves (Canis lu- But how can the intended use of a bance event in YNP in over a centu- pus) is being debated, and there is wilderness area be objectively deter- ry—probably will cause the demise of considerable pressure to reduce the mined? Is it a matter to be decided by certain park features that managers, elk (Cervus elaphus) population. An- public opinion? What can science con- scientists, and the general public feel other controversy developed over tribute? In this article, we take a land- are important. Asserting with confi- whether the Greater Yellowstone scape perspective in synthesizing eco- dence that YNP is large enough for Area (GYA) is large enough to sup- logical information and concepts uncontrolled disturbances is not pos- port grizzly bears (Ursus arctos) with- relevant to the continuing challenge of sible with available information, but out supplemental food. Park manage- natural area management. We address after the fires, extensive tracts of un- ment policies continue to evolve as fire-caused temporal and spatial vari- burned forest remain and wildlife is new information is obtained. ability in vegetation patterns, plant- expected to recover (Christensen et al. The effects of fire suppression, animal relationships, and land-water page 678 this issue). predator control, and supplemental interactions in YNP. The pre-1988 Yellowstone land- feeding often have been difficult to scape consisted of a mosaic of mead- assess. To be sure, they have changed Temporal and spatial scales ows, aquatic ecosystems, unforested the character of Yellowstone. As Aldo in Yellowstone ridges and peaks, geyser basins with Leopold wrote about Glacier Na- little vegetation, and forests of dif- tional Park in 1927, "The balance of All landscape mosaics change ferent species composition and age nature in any strict sense has been through time, and it is unrealistic to (i.e., successional stages since previ- upset long ago . . . The only option expect that Yellowstone should not ous disturbances). This spatial mosaic we have is to create a new balance change as well. On a scale of millen- is a function of past disturbances su- objectively determined for each area nia, it has changed since the retreat of perimposed on environmental gradi- in accordance with the intended use the glaciers, and, on a scale of centu- ents, whether abrupt or gradual. The ries, it has changed since the large fires of 1988 burned unevenly across fires of the early 1700s (Romme and this sometimes patchy, sometimes ho- Dennis Knight is a professor in the De- Despain page 695 this issue). Shifts in partment of Botany at the University of mogeneous landscape. In some areas, Wyoming, Laramie, WY 82071, and climatic conditions have caused land- the patchiness was increased by the Linda Wallace is an associate professor in scape changes at both time scales, as fires; in others the fires appear to have the Department of Botany and Microbiol- caused more uniformity. In either ogy, University of Oklahoma, Norman, Letter from Aldo Leopold to Charles J. case, research is necessary to deter- OK 73019. © 1989 American Institute of Kraebel, Superintendent of Glacier National mine if the area and spatial variability Biological Sciences. Park, 18 January 1927. of the park are sufficient to maintain

700 BioScience Vol. 39 No. 10 the processes, biotic diversity, and Interestingly, not all lodgepole pine other features that make Yellowstone are serotinous. Muir and Lotan (1985a) unique. found that serotinous and nonserotinous trees usually coexist, with the Temporal and spatial patterns relative abundance of each dependent on the last disturbance. They observed in terrestrial vegetation that where the last major disturbance In general, the terrestrial vegetation was caused by factors other than fire of the Yellowstone region is charac- (e.g., insects or wind), more of the terized by extensive lodgepole pine lodgepole pine are nonserotinous. (Pinus contorta var. latifolia) forests, With the long time period between sporadic forests of Engelmann spruce fires in most subalpine coniferous for- (Picea engelmanii) and subalpine fir ests in the GYA, especially where fire (Abies lasiocarpa) at higher eleva- suppression was effective, there is a tions, Douglas fir (Pseudotsugu men- greater chance for nonserotinous trees ziesii) forests and woodlands at lower to be more common. The proportion elevations, scattered aspen (Populus of each reproductive strategy before tremuloides) groves, woodlands dom- 1988 is unknown, but it probably var- inated by limber pine (Pinus flexilis) ied considerably from place to place. and whitebark pine (Pinus albicaulis), The serotinous cones of lodgepole occasional sagebrush (Artemisia tri- pines are unique, but other plants are dentata) grasslands and mountain adapted to fire as well. Most of the meadows, and riparian vegetation grasses, forbs, and shrubs are capable comprised of sedge/grass meadows of sprouting, an adaptation that and willow (Salix spp.) thickets (De- surely must have evolved as a means spain 1973, Romme and Knight of surviving fire as well as grazing, 1982). Fire has played an important drought, and cold winters. Above- role in shaping vegetation distribu- ground parts of many plants may be tion patterns (Despain and Sellers charred or even completely burned, 1977, Gruell and Loop 1974, Hous- but much of the root system remains ton 1973, Loope and Gruell 1973, unharmed because soil temperatures Romme 1982, Romme and commonly are not elevated to lethal Despain page 695 this issue, Romme limits. Energy reserves in the surviv- and Knight 1982, Taylor 1969, 1973, ing root systems allow for the produc- 1974). Sharp transitions from young tion of new stems and leaves within a to old forest are readily apparent, year, and the increased availability of marking the boundaries of earlier sunlight, water, and nutrients allows fires. Fire-scarred trees are common, for increased seed production, which and charcoal is easy to find in the facilitates the establishment of new surface soil of forested areas. plants.

Plant adaptations. The plants are well Predicting regrowth. In the Yellow- adapted to fire. The serotinous stone area, ecosystem development (closed cone) feature of lodgepole after fire is easiest to predict where pine is mentioned often in this regard, sprouting growth forms were domi- and it is interpreted as an adaptation nant before the fires. For example, for taking advantage of the abundant burned aspen groves are expected to Figure 1. Burned forest two years after a water, nutrients, and space made respond quickly by root sprouting 1979 fire in Yellowstone National Park, showing high understory cover and many available for new plants immediately (Jones and DeByle 1985). Most of the standing dead trees. Some areas of this after a burn (Lotan 1975, Muir and understory plants will sprout also. burn have less understory cover than Lotan 1985a,b). Such cones allow for Although the physiognomy of the shown in this photo. the storage of large quantities of seed groves will be altered dramatically, during periods of many years, with with a high density of young sprouts the seed being dispersed when the instead of widely spaced older trees, physiognomic (Leege 1969). Brows- heat of a fire cracks the resin bonds on the species composition changes com- ing by herbivores may increase be- cone scales. Apparently few of the paratively little, and the aspen grow cause of the increased abundance of seeds are burned. Cone serotiny al- rapidly. more succulent and possibly more nu- lows for the development of the even- Much the same scenario is appro- tritious sprouts. As with the aspen aged stands (±2020 years or more) that priate for the riparian meadows and groves, scientists have the opportu- characterize much of the Rocky shrublands. Here, too, most of the nity to observe recovery in the pres- Mountains where fire is a frequent plants are expected to resprout vigor- ence of large ungulate populations disturbance. ously, and the changes will be mainly and to ascertain how well the plants

November 1989 701 are adapted to high levels of her- rotinous, or where spruce and subal- years after the fires). Such a wide bivory. pine fir were the dominants, tree seed- range of conditions rarely occurs in Grasslands with big sagebrush are lings and saplings may be sparse for wildlands that have been managed to common in some parts of the GYA one or more decades. Some areas a large extent for their educational and probably were altered more dra- could become meadows if conditions and scientific value. Also, YNP pro- matically than the riparian vegetation are marginal for tree growth, whether vides opportunities for long-term re- and aspen groves. Big sagebrush, of- due to intense competition from her- search. The results should be applica- ten the dominant plant, cannot baceous vegetation or environmental ble to resource interpretation and sprout, and thus it is greatly reduced conditions that prevent tree seedling management in the park and through- in abundance after fires. However, establishment (Stahelin 1943). out the region. surviving sagebrush plants produce Although the prospect of forest- Another opportunity for study is many seeds, which germinate readily. to-meadow conversions may be the invasion by introduced plants. Sprouting grasses and forbs are the alarming to some, this conversion There might appear to be little basis dominants until new sagebrush seed- probably has occurred before. Mead- for concern about damage by intro- lings become established and grow to ows can enhance wildlife habitat and duced plants, because weed popula- maturity, perhaps 15 to 30 years landscape diversity. tions in the park were low before the later. Big sagebrush can be an impor- However, conifers are likely to be- fires, with most species restricted to tant winter food, especially for mule come re-established in most of the road ditches and other areas of hu- deer (Odocoileus hemionus) and burned coniferous forests. Lodgepole man impact. Previous fires apparently pronghorn (Antilocarpa americana). pine or Engelmann spruce probably had not provided habitat for such The impact of this food loss remains will be the most common dominants plants. However, the last large fires to be seen, but only a small portion in the young forest, with Douglas fir occurred around 1700, when there (9%) of YNPs winter range was well represented at lower elevations. were no seed sources for exotic plants burned. These three species seem best adapted adjacent to the park. Now such plants During the next few decades, the for seedling establishment on mineral are abundant nearby. Furthermore, effects of the fires are expected to be soil in open areas (Alexander 1987). the extensive fires of 1988 created most easily seen in the coniferous Lodgepole pine (and some aspen) invasion corridors into the park (i.e., forests, as none of the conifers in seedlings were commonly observed in open habitats where nonsprouting co- Yellowstone have the ability to intensively burned forest in 1989. nifers were killed by fire and where sprout. Where aspen coexisted with Standing dead trees from the 1988 fire-fighting activities scarified the conifers, the forest will likely be con- fires are expected to be conspicuous soil). verted temporarily to aspen. How- for 20 years or more, but some will A third research opportunity per- ever, the spruce, fir, and pines are fall each year until the snags are a tains to the effects of fire suppression. expected to become dominant again minor feature of the landscape. The Despite confident pronouncements in most areas after a century or more successional sequences can vary con- about fire suppression causing the (Stahelin 1943, Peet 1988). siderably (Aplet et al. 1988, Brown large-scale 1988 fires, such effects un- Forest regeneration is expected to 1975, Despain 1983, Romme and doubtedly varied from place to place. be slower where aspen was absent. Knight 1981, Stahelin 1943, Veblen Houston (1982) showed clearly that Initially, the grasses, sedges, forbs, 1986, Whipple and Dix 1979), a fact fire suppression led to an increase in and shrubs may form a dense cover that contributed to the vegetation di- the density of Douglas fir and sage- under the standing trees killed by the versity that existed in Yellowstone brush at lower elevations in the north, fire (Figure 1). Species composition is before the 1988 fires and which is but other information suggests that expected to vary greatly, as is the expected to prevail again as the mo- fuel accumulation is slow on the amount of cover, and typically the saic of successional patterns becomes higher Yellowstone Plateau—so slow herbaceous plants appear unusually superimposed on the burn mosaic. Of that 40 years of effective fire suppres- green and lush—an indication of im- course, the forests that were not sion (since the mid-1940s) would proved water and nutrient availabil- burned in 1988 will continue to have had a minor effect (Romme and ity. In some areas, the growth of change as well. Despain page 695 this issue). During herbs and shrubs is expected to be the drought of 1988, young forests slow because the fire was unusually Research opportunities. YNP now with little fuel burned along with the hot, killing root systems and orga- provides unique opportunities for re- highly flammable old growth.2 nisms important for plant growth search on postfire succession because An interesting dimension to the fire (e:g., mycorrhizal fungi), because tree the fires created so many variations in suppression issue is the importance of density before the fires was high factors that influence community Indian fires before Europeans arrived. enough to preclude understory plants, change (topographic position, soil Some suggest that such fires kept the or because of severe environmental characteristics, burn intensity, pre- forests of Yellowstone more open and conditions. burn species composition, preburn less flammable, especially the north- Tree seedlings are expected to be- tree density, seed bank species com- ern Douglas fir forests at lower eleva- come obvious 5-10 years after the position, distance from unburned for- fires and could be dense where seroti- est, intensity of postfire herbivory, 2Richard Rothermel, 1989, personal communi- nous lodgepole pine dominated the patchiness of the burn mosaic, and cation. Intermountain Research Station, USDA forest. Where the pines were not se- climatic conditions in the first few Forest Service, Missoula, MT.

702 BioScience Vol. 39 No. 10 Lions (Barrett and Arno 1982). Else- not just a matter of physiognomic after fires. Nutrient availability for where, however, the journals of early discontinuities, with food and cover the plants in such sites is enhanced by explorers in Yellowstone suggest in close proximity. Burned patches reduced competition from trees, but dense forests. For example, General usually are fringed by a halo of trees also because of nutrient accumulation W. E. Strong wrote after his 1875 trip with brown needles, the result of through urine and feces. Also, her- into Yellowstone (Strong 1968), "The singeing where fire intensity was in- bivory is known to affect the rate trees have been falling here for centu- adequate for complete combustion. and direction of nutrient movement ries, and such a network of limbs, Some of these trees die because the (Merrill 1978, Ruess and McNaugh- trunks, and stumps has been formed, proportion of singed needles is too ton 1988, Schimel et al. 1986). Fur- that to face it with a horse . . . is high or because too much of the cam- thermore, the postfire forage often enough to appall the stoutest heart bium of the thin-barked lodgepole is more nutritious (McNaughton . . . The woods are fearful to travel pine has been burned. However, oth- 1979, Wood 1988) and the ratio of through, covered with . . . pine . . . so ers survive. Fire-scarred trees dating green tissue to dead or supportive thick and close that our horses could, back to 1988 are expected to delin- tissue is higher than elsewhere, two at times, barely squeeze through. . . ." eate the fire mosaic long after it is no factors contributing to foraging effi- longer conspicuous. ciency. Shifting animal Furthermore, trees scarred by fire After fires, ungulates can establish could serve as epicenters for out- new movement corridors linking wa- distribution patterns breaks of insects such as mountain ter, bedding grounds, calving areas, Approximately 25-30% of YNP (and pine beetles (Dendroetonus pondero- and summer and winter ranges. Ani- a smaller percentage of the GYA) was sae; Gara et al. 1985, Geiszler et al. mals can influence rates of productiv- affected in 1988 by canopy fires, 1980). Insect outbreaks could con- ity and vegetation development, and which greatly modified forest physi- tribute to the development of a fuel thereby they could affect the land- ognomy. Abundant dead and dying complex that makes fires more prob- scape mosaic that develops. Yellow- trees now stand in these areas, creat- able in future drought years (Knight stone now provides excellent oppor- ing habitat very different from the 1987). In this way, disturbances of tunities for studies on the interaction unburned forest. Herbaceous or one kind have an influence on the of fire, free-roaming ungulates, and shrubby vegetation accounts for most spread of disturbances of other vegetation recovery across a variable of the photosynthesis in areas sub- kinds—a primary theme in landscape landscape that is comparatively free jected to canopy fires; berries and ecology (Turner 1987). from logging activity and roads. other fleshy fruits will become more Insect outbreaks in the singed-tree common. The habitat is more open, halos may, however, be kept in check Land-water-nutrient and an edge (between burned and by insectivorous birds. Woodpeckers interactions unburned forest) favorable for some are known to be more common in wildlife has been created in some ar- burned areas (Taylor and Barmore Disturbances to terrestrial ecosystems eas. Prey animals such as small ro- 1980), and they undoubtedly will invariably lead to changes in aquatic dents are more visible and, not feed among the weakened trees on the ecosystems (Minshall et al. page 707 surprisingly, raptors and some insec- edge as well, where some insects this issue). Leaf-area reduction in co- tivorous birds are attracted to the could be more common. The edge niferous forests, whether due to fire burned forests (Taylor and Barmore created by a burn is more complex or insects, reduces evapotranspiration 1980). In general, within a few years than the edge created by timber har- and increases subsequent streamflow. after fires, species diversity of plants vesting, and the great diversity of With reduced canopy cover and nu- and animals is higher (Taylor 1973, complex edges created in Yellowstone trient uptake after fires, there is in- Taylor and Barmore 1980). provides excellent opportunities for creased potential for erosion and nu- research on predator-prey relation- trient losses from the upland (Knight Edges. Aerial views of the Yellow- ships. et al. 1985). In addition to flooding, stone landscape suggest that more there is the potential for declines in edge has been created by some fires Ungulates. The population sizes and soil fertility that affect subsequent than others (see page 682). However, foraging areas of large mammals also successional patterns and increases in data must be collected to verify this are expected to be affected by the sedimentation and nutrient inputs observation, as some fires burned fire-caused changes in vegetation that affect stream and lake productiv- across edges between young and old (Singer et al. page 716 this issue). ity. Predicting the outcome in Yellow- forest during the unusual drought These changes could have significant stone is still a challenge. conditions of 1988. Observations effects on nutrient transfer and the thus far suggest that the early summer productivity of different parts of the Flooding. Flooding that could have burns were more patchy, thereby cre- mosaic. In general, some ungulates adverse effects on downstream settle- ating more edge, whereas burning use the forest edge, commonly select- ments is a distinct possibility. How- later in the summer was more uni- ing habitats with forage and cover in ever, it did not occur in 1989, even form and more likely to cross edges close proximity. New edges could be though snowpack water equivalents when fuels were drier and winds more attractive than old edges be- were average or slightly above (99- stronger. cause of the vigorous growth of her- 120% of a 30-year average), because The edges created by the fires are baceous plants that typically occurs climactic conditions were conducive

November 1989 703 tions in 1989 indicate that erosion after rainstorms was greater than during snowmelt. The riparian zones, as elsewhere, experienced different intensities of burning. In the most severely burned areas, sedge peat was burned down to mineral soil, killing the rhizomes and root systems. In other riparian areas, sprouting is vigorous. The rapid regrowth and accompanying nutrient uptake of lightly burned areas could actually increase filtering capacity, whereas the severely burned areas will have reduced filtering capacities. The fires provide exceptional opportunities for research on the effects of disturbances at the terrestrial-aquatic interface.

Nutrient losses. Even without erosion, there is the potential for nutrient losses from the burned forest soils, with the loss of limiting elements such as nitrogen being of special interest. Figure 2. A broad riparian zone typical of some rivers in the Yellowstone area. Some nitrogen is volatilized during Elsewhere the riparian zone may be more narrow, providing little filtering capacity for fires, but this loss probably is minor sediments and nutrients originating on the upland. compared to losses via leaching as water percolates down through the soil profile. Nitrification typically ac- to slow snowmelt.3 Also, the lack of should not create flooding problems celerates after disturbances in conifer- dramatically increased streamflow in for downstream settlements, unless ous forests, converting the relatively 1989 can be partially attributed to precipitation is abnormally high. In immobile ammonium cation to the high soil storage capacity due to the fact, the additional streamflow could highly leachable nitrate (Fisher and 1988 drought. With reduced evapo- be a welcome addition to currently Gosz 1986, Hart et al. 1981, Vi- transpiration in 1989 due to less leaf low water levels in downstream reser- tousek and Mellilo 1979). As a result, area in burned areas, the soil is ex- voirs. the nitrogen pool in the soil may pected to have less storage capacity in decline for a period of time (Fahey et 1990 and the potential for flooding Erosion. Although erosion can deal. 1985, Fahey and Knight 1986). could be considerably higher. After grade soil fertility or water quality, However, the loss of nitrogen after lumber operations, increased stream- the occasional episodes of erosion in fire probably is not a problem, be- flow has been observed in some areas the GYA probably are tolerable because the nitrogen requirements of for 25 years or more—the time re- cause background levels are so low. the early postfire vegetation are small quired for the restoration of the orig- Some bottom sediments from lakes and the nitrogen lost by volatilization inal amounts of leaf area and canopy have layers with charcoal fragments, and leaching is replaced by continued cover (Troendle 1983). suggesting that erosion after fires has atmospheric deposition, fixation, and Concerned about the potential for occurred in the past (Mehringer decomposition of soil organic matter flooding, the Soil Conservation Service 1985). In 1989, rivers were some- (the largest pool of nitrogen in the used a regression model for predicting times black with sediments after forest ecosystem; Fahey et al. 1985). the effects of fires on streamflow in the heavy rains. A portion of postfire nutrient losses GYA (Fames and Hartman 1989). Yellowstone streams and rivers are from upland areas becomes a gain of Their model incorporated data on re- often fringed by riparian meadows nutrients for aquatic ecosystems. duced forest cover due to canopy fires. and shrublands that filter sediments Limnologists are now challenged with Assuming typical climatic conditions, during some periods of erosion (Fig- determining if and for how long spring streamflow was predicted to ure 2), thereby minimizing the amount stream and lake productivity increase increase by no more than 2-13%, of sediments entering the water. In as a result of the 1988 fires (Minshall depending on watershed characteris- other areas, however, surface runoff et al. page 707 this issue). tics. Increases of this magnitude from adjacent uplands could be chan- nelized before it reaches the riparian Variation. From a landscape perspec- 3P. E. Fames, 1989, personal communica- zone, with the result that little riparian tive, the effects of fires on water quan- tion. Soil Conservation Service, Bozeman, filtration is possible and the sediment tity and quality will vary greatly from MT. load is added to the stream. Observa- one watershed to another. Streams

704 BioScience Vol. 39 No. 10 draining watersheds that have been • terest and highlighted the difficulties completely burned and that have a Patchiness of Burn Mosaic of natural area management. narrow riparian zone (low filtering c0 Aldo Leopold called for objectively capacity) will be affected more dra- 0 determined goals in natural area man- matically, with the effect diminishing :5. agement. If such goals are possible, as the size of the riparian zone in- a they must reflect the results of past creases or as the extent of burning research. They also must be flexible, decreases. A promising parameter to a as there is much that is not known E compare with various water-quality Proportion of Watershed in Riparian Ecosystems about the ecological phenomena that characteristics is the ratio between the we seek to protect. proportion of the upland that was Additional opportunities now exist burned to the proportion of the wa- in Yellowstone to better understand tershed that is riparian (burned or the effects of disturbances on interac- unburned; Figure 3). Such ratios tions within and between the patches could be usefully integrated with in- of specific community types that com- formation on burn intensity, the de- prise the landscape mosaic and how gree of burn patchiness, and slope % Watershed Burned by Canopy Fire changes in the mosaic affect animal steepness. populations, aquatic ecosystems, and the spread of future disturbances. Be- Determining the quantitative rela- Figure 3. Hypothetical relationships be- tionships between landscape varia- tween changes in streamflow or water cause of its large size, the park now bles, water quality, and stream or quality, percent of watershed burned, more than ever can provide a basis for lake productivity has been proposed patchiness of the burned landscape (top), refining land management policies in by others (e.g., Lee and Gosselink and the proportion of the burned water- the GYA and beyond. An unusually 1988) and seems especially feasible in shed in riparian ecosystems (burned or large segment of the public will be Yellowstone, again because such a unburned) that could filter nutrients and interested in the results. wide range of conditions could be sediments (bottom). examined. Rather than the traditional Acknowledgments comparisons of burned and unburned watersheds, a gradient analysis of as a result of the 1988 fires. Change Helpful comments on the manuscript burn effects is possible. A significant continues in ways that influence nat- were provided by Mark S. Boyce, advantage of conducting such studies ural selection. Like acid precipitation, Norman L. Christensen, Phillip E. in YNP is that the effects of roads and atmospheric carbon dioxide enrich- Fames, George P. Jones, Bruce P. Mc- other human influences would be ment, the spread of toxins, and vari- Clure, Mary Meagher, Evelyn H. minimized. ous issues in wildlife management, Merrill, Patricia S. Muir, William the Yellowstone fires have challenged F. J. Parsons, William A. Reiners, and ecologists to extend their data and Paul Schullery. Our research in Yel- Conclusions research to the scale of landscapes lowstone has been supported by the In general, the effects of the 1988 fires and the biosphere. In all cases, there National Park Service, the University on terrestrial vegetation are expected are many uncertainties due to the of Wyoming/National Park Service to be more vigorous herbaceous veg- complexity of the interactions and the Research Center, and the National etation for several decades; a larger diverse mosaic. Learning the far- Science Foundation (DEB 81-13546, portion of YNP in young forests or reaching effects of changing (or static) BSR-8805983). nonforested area; aspen forests over a landscape mosaics is perhaps the larger area, though still a small por- greatest challenge. References cited tion of the park; less sagebrush in The 1988 fires stimulated new in- Alexander, R. R. 1987. Ecology, silviculture, some areas for a decade or more; and terest in the management of natural and management of the Engelmann spruce- a larger area of open woodlands or areas. The inevitability and impor- subalpine fir type in the Central and South- savannas, especially at lower eleva- tance of disturbances are widely rec- ern Rocky Mountains. USDA Forest Service tions where mature, thick-barked ognized (Loucks 1970, Pickett and Agriculture Handbook 659, Washington, DC. Douglas fir predominated and the White 1985, Wright 1974), but some Aplet, G. H., R. D. Lavin, and F. W. Smith. fires were less intense. Concomitant scientists and politicians alike had not 1988. Patterns of community dynamics in changes can be expected in animal thought enough about the historical Colorado Engelmann spruce-subalpine fir population sizes, animal distribution, evidence suggesting that truly large forests. Ecology 69: 312-319. fires occur at intervals of two or more Barrett, S. W., and S. F. Arno. 1982. Indian and some predator-prey relation- fires as an ecological influence in the north- ships. Sediment and nutrient addi- centuries. Others thought that gener- ern Rockies. J. For. 80: 647-651. tions to aquatic ecosystems will vary alizations were possible over large Bonnicksen, T. M. 1988. Restoration ecology: with the extent, patchiness, and inten- areas such as YNP, or that somehow philosophy, goals, and ethics. Enivron. Prof. sity of fires and with the filtering the park would never (or should 10: 25-35. never) change in any significant way. 1989. Fire gods and federal policy. capacity of the riparian zone. Am. For. 95: 14-16,66-68. Research suggests that most plants The debates that developed, though Brown, J. K. 1975. Fire cycles and community are well adapted to fire and that biotic often ill-conceived from a scientific dynamics in lodgepole pine forests. Pages diversity in the GYA will not decline viewpoint, stimulated great public in- 429-456 in D. M. Baumgartner, ed. Man-

November 1989 705 agement of Lodgepole Pine Ecosystems. Fort Collins, CO. torical perspective on the Yellowstone fires Washington State University Cooperative Knight, D. H. 1987. Parasites, lightning, and of 1988. BioScience 39: 695-699. Extension Service, Pullman. the vegetation mosaic in wilderness land- Romme, W. H., and D. H. Knight. 1981. Fire Christensen, N. L., J. K. Agee, P. F. Brussard, scapes. Pages 59-83 in M. G. Turner, ed. frequency and subalpine forest succession J. Hughes, D. K. Knight, G. W. Minshall, Landscape Heterogeneity and Disturbance. along a topographic gradient in Wyoming. J. M. Peek, S. J. Pyne, F. J. Swanson, J. W. Springer-Verlag, New York. Ecology 62: 319-326. Thomas, S. Wells, S. E. Williams, and H. A. Knight, D. H., T. J. Fahey, and S. W. Running. 1982. Landscape diversity: the con- Wright. 1989. Interpreting the Yellowstone 1985. Water and nutrient outflow from concept applied to Yellowstone Park. BioScience fires of 1988. BioScience 39: 678-685. trasting lodgepole pine forests in Wyoming. 32: 664-670. Despain, D. G. 1973. Major vegetation zones Ecol. Monogr. 55: 29-48. Ruess, R. W., and S. J. McNaughton. 1988. of Yellowstone National Park. Yellowstone Lee, L. C., and J. G. Gosselink. 1988. Cumula- Ammonia volatilization and the effects of National Park Information Paper 19, Yel- tive impacts on wetlands: linking scientific large grazing mammals on nutrient loss from lowstone, WY. assessments and regulatory alternatives. East African grasslands. Oecologia 77: 382- . 1983. Nonpyrogenous climax lodge- Enivron. Manag. 12: 591-602. 386. pole pine communities in Yellowstone Na- Leege, T. A. 1969. Burning seral brush ranges Schimel, D. S., W. J. Parton, F. J. Adamsen, tional Park. Ecology 64: 231-234. for big game in northern Idaho. Trans. N. R. G. Woodmansee, R. L. Senft, and M. A. Despain, D. G., and R. E. Sellers. 1977. Natu- Am. Wildl. Nat. Resour. Conf. 34: 429-438. Stillwell. 1986. The role of cattle in the ral fires in Yellowstone National Park. West. Loope, L. L., and G. E. Gruell. 1973. The volatile loss of nitrogen from a shortgrass Wildlands 4: 20-24. ecological role of fire in the Jackson Hole prairie. Biogeochemistry 2: 39-52. Fahey, T. J., and D. H. Knight. 1986. Lodge- area, northwestern Wyoming. Quat. Res. 3: Singer, F. J., W. Schreier, J. Oppenheim, and pole pine ecosystems. BioScience 36: 610- 425-443. E. 0. Garten. 1989. Drought, fires, and large 617. Lotan, J. E. 1975. The role of cone serotiny in mammals. BioScience 39: 716-722. Fahey, T. J., J. B. Yavitt, J. A. Pearson, and lodgepole pine forests. Pages 471-495 in Stahelin, P. 1943. Factors influencing the nat- D. H. Knight. 1985. The nitrogen cycle in D. M. Baumgartner, ed. Management of ural restocking of high altitude burns by lodgepole pine forest, southeastern Wyo- Lodgepole Pine Ecosystems. Symposium coniferous trees in the central Rocky Moun- ming. Biogeochemistry 1: 257-275. proceedings. Washington State University tains. Ecology 24: 19-30. Fames, P. E., and R. K. Hartman. 1989. Esti- Cooperative Extension Service, Pullman. Strong, W. E. 1968. A trip to the Yellowstone mating the effects of wildfire on water sup- Loucks, 0. L. 1970. Evolution of diversity, National Park in July, August, and Septem- plies in the northern Rocky Mountains. Pa- efficiency, and community stability. Am. ber, 1875. University of Oklahoma Press, per presented at the 57th Western Snow Zoo!. 10: 17-25. Norman. Conference, Fort Collins, CO. 18-20 April McNaughton, S. J. 1979. Grassland-herbivore Taylor, D. L. 1969. Biotic succession of lodge- 1989. dynamics. Pages 46-81 in A. R. E. Sinclair pole pine forests of fire origin in Yellowstone Fisher, F. M., and J. R. Gosz. 1986. Effects of and M. Norton-Griffiths, eds. Serengeti: Dy- National Park. Ph.D. dissertation, University trenching on soil processes and properties in namics of an Ecosystem. University of Chi- of Wyoming, Laramie. a New Mexico mixed-conifer forest. Biol. cago Press, Chicago. 1973. Some ecological implications of Fertil. Soils 2: 35-42. Mehringer, P. J. Jr. 1985. Late-Quaternary pol- forest fire control in Yellowstone National Gara, R. I., W. R. Littke, J. K. Agee, D. R. len records from the interior Pacific North- Park, Wyoming. Ecology 54: 1394-1396. Geiszler, J. D. Stuart, and C. H. Driver. west and northern Great Basin of the United 1974. Forest fires in Yellowstone Na- 1985. Influence of fires, fungi, and mountain States. Pages 167-189 in F. M. Bryant Jr. tional Park. Forest History 18: 69-77. pine beetles on development of a lodgepole and R. G. Holloway, eds. Pollen Records of Taylor, D. L., and W. J. Barmore Jr. 1980. pine forest in south-central Oregon. Pages Late-Quaternary North American Sedi- Post-fire succession of avifauna in coniferous 153-162 in D. M. Baumgartner, R. G. Kre- ments. American Association of Strati- forests of Yellowstone and Grand Teton bill, J. T. Arnott, and G. F. Weetman, eds. graphic Palynologists, Dallas, TX. National Parks, Wyoming. Pages 130-145 in Lodgepole Pine: The Species and Its Man- Merrill, E. H. 1978. Nutrient cycling in an R. M. DeGraff, ed. Proceedings of the Work- agement. Washington State University Coop- ungulate-vegetation complex, Selway River, shop on Management of Western Forests and erative Extension Service, Pullman. Idaho. Ph.D. dissertation, University of Grasslands for Non-game Birds. US Forest Geiszler, D. R., R. I. Gara, C. H. Driver, V. F. Idaho, Moscow. Service General Technical Report INT-86, Gallucci, and R. E. Martin. 1980. Fire, fungi, Minshall, G. W., J. T. Brock, and J. D. Varley. Ogden, UT. and beetle influences on a lodgepole pine 1989. Wildfires and Yellowstones stream Troendle, C. A. 1983. The potential for water ecosystem in south-central Oregon. Oecolo- ecosystems. BioScience 39: 707-715. yield augmentation from forest management gia 46: 239-243. Muir, P. S., and J. E. Lotan. 1985a. Distur- in the Rocky Mountain region. Water Re- sour. Bull. Gruell, G. E., and L. L. Loope. 1974. Relation- bance history and serotiny of Pinus contorta 19: 359-373. ships among aspen, fire and ungulate brows- in western Montana. Ecology 66: 1658- Turner, M. G., ed. 1987. Landscape Heteroge- 1668. neity and Disturbance. Springer-Verlag, Ber- ing in Jackson Hole, Wyoming. US Forest lin, FRG. Service Special Publication, Jackson, WY. . 19856. Serotiny and life history of Veblen, T. T. 1986. Treefalls and the coexist- Hart, G. E., N. V. DeByle, and R. W. Hennes. Pinus contorta var latifolia. Can. J. Bot. 63: 938-945. ence of conifers in subalpine forests of the 1981. Slash treatment after clearcutting central Rockies. Ecology 67: 644-649. lodgepole pine affects nutrients in soil water. Peet, R. K. 1988. Forests of the Rocky Moun- J. For. Vitousek, P. M., and J. M. Mellilo. 1979. Ni- 79: 446-450. tains. Pages 64-101 in M. G. Barbour and trate losses from disturbed forests: patterns Houston, D. B. 1973. Wildfires in northern W. D. Billings, eds. North American Terres- and mechanisms. For. Sci. 25: 605-619. Yellowstone National Park. Ecology 54: trial Vegetation. Cambridge University Press, Whipple, S. A., and R. L. Dix. 1979. Age struc- 1111-1117. New York. ture and successional dynamics of a Colo- 1982. The Northern Yellowstone Elk: Pickett, S. T. A., and P. S. White, eds. 1985. rado subalpine forest. Am. Midl. Nat. 101: Ecology and Management. Macmillan, New The Ecology of Natural Disturbance and 142-158. York. Patch Dynamics. Academic Press, New Wood, G. W. 1988. Effects of prescribed fire Jones, J. R., and N. V. DeByle. 1985. Fire. York. on deer forage and nutrients. Wildl. Soc. Pages 77-81 in N. V. DeByle and R. P. Romme, W. H. 1982. Fire and landscape diver- Bull. 16: 180-186. Winokur, eds. Aspen: Ecology and Manage- sity in subalpine forests of Yellowstone Na- Wright, H. E. Jr. 1974. Landscape development in the Western United States. US Forest tional Park. Ecol. Monogr. 52: 199-221. ment, forest fires, and wilderness manage- Service General Technical Report RM-119, Romme, W. H., and D. G. Despain. 1989. His- ment. Science 186: 487-495.

706 BioScience Vol. 39 No. 10 Wildfires and Yellowstones Stream Ecosystems A temporal perspective shows that aquatic recovery parallels forest succession

G. Wayne Minshall, James T. Brock, and John D. Varley

ew studies have examined the Fire and landscape effect of fire on the aquatic Effects of the fires are heterogeneity F biota, and none has adequately addressed major aspects of aquatic ec- likely to be most The heterogeneous nature of the land- osystem function. Most of the research scape, due in part to the varying ex- has examined the effects of fire on pronounced in tents of patchiness of the 1988 fires water chemistry (Schindler et al. 1980, headwaters (Figure 1), has important implications Tiedemann et al. 1979). Nevertheless, for the fire impact on GYA stream it is possible to develop a set of predic- ecosystems, The intensity of each fire tions regarding the immediate, near- varied from hot canopy fires (61% of term, and long-term consequences of 94% of the parks water area, had the burned area), to cooler ground the 1988 fires in the Greater Yellow- significant portions of their drainages fires, to unburned patches of less than stone Area (GYA) by supplementing burned (Figure 1). Twenty-eight per- 50 ha. Although the percentage of the existing information base on fire cent of the Yellowstone Lake water- each burn type was remarkably simi- response and general ecological behav- shed, 8% of the Shoshone Lake drain- lar among the six major fires, the ior of aquatic ecosystems with knowl- age, 33% of the Lewis Lake drainage, extent of patchiness varied consider- edge of the response of aquatic sys- and 50% of the Heart Lake water- ably. Fires early in the summer, when tems to logging and to physical shed were affected by fire to some fuel-moisture levels were higher, gen- disturbances within the channel. degree. erally were patchier than those that Of the 0.57 million ha of the GYA In general, loss of vegetation is ex- burned later. After July 21, fires fre- that burned (Burned Area Survey pected to increase water runoff, but quently were driven by 65-95 km/hr Team 1988), most (95%) of the area not beyond the normal variability of winds and tended to include wide was forest, and the remainder was the hydrologic systems. Due to differ- swathes of continuous canopy burn meadow, grassland, and sagebrush ences in landscape morphology and in with spotting by secondary fires to the scrubland. Twenty separate river ba- the nature of the fires, streams in the sides and in front. sins or major subbasins were affected Madison, Upper Yellowstone (above Fire impact on different streams is by the fires to various degrees (Figure Yellowstone Lake), and Snake river expected to vary proportionally with 1). Within Yellowstone National drainages are less likely to be affected the intensity and extent of burning of Park (YNP), approximately 32% by the 1988 fires than the other main a watershed and the vegetation for- (1380 km2) of the stream system was river systems in the GYA. merly present. Responses are most influenced by the fires. In addition, The major effects are expected to likely to be seen in watersheds where the four large oligotrophic lakes (Yel- parallel the forest recovery and, dur- the upper portions were heavily for- lowstone, Shoshone, Lewis, and ing the next 300 years, gradually re- ested and were extensively burned Heart lakes), which together make up turn the aquatic ecosystem to the pre- (e.g., Lava, Tower, and Blacktail Deer fire state. The fires are expected to creeks). alter buildup of woody debris, sedi- The impact also is expected to vary G. Wayne Minshall is a professor of ecol- ment suspension, nutrient cycling, along a given stream system. The ogy and zoology and James T. Brock is a leaf litter input, and the types of greatest impacts of fire probably will research associate in the Department of Biological Sciences, Idaho State Univer- aquatic organisms present. These ef- be seen in smaller (headwater) sity, Pocatello, ID 83209. John D. Varley fects are expected to be more pro- streams, and the effects will progres- is the chief of research at the National nounced in headwater streams, and sively dissipate downstream, except Park Service, Yellowstone National Park, they are likely to diminish with in- in reaches where fire-perturbed small WY 82190. creased stream size. tributaries enter a large mainstem

November 1989 707 greatest in the upper subdrainages of Lamar River, Crandall Creek, and North Fork Shoshone River. These subdrainages are characterized by steep slopes (greater than 45%), shal- low soils, unstable geology, and intense summer thunderstorms (Hy- drology Assessment Team 1988). In the Madison, upper Yellow- stone, and Snake river systems, slopes generally are less steep, valley bottoms wider, and stream gradients lower. Also, the proportion of burned area on steep slopes is smaller. The result is that, even with some increases in water yield due to the reduction of vegetation by fire, the time of concentration of streamflow is lengthened by basin morphology, flood peaks are better regulated, and flooding is less likely (Hydrology As- sessment Team 1988). -f-vfese Temporal responses of stream ecosystems to fire Stream ecosystem responses are closely linked to terrestrial plant conditions in the surrounding watershed (Hynes 1975, Minshall et al. 1985, Vannote et al. 1980). Therefore, changes in the structure and composition of terrestrial vegetation after wildfire (Arno et al. 1985, Lyon 1984, Romme 1982) may be expected to influence the adjacent streams. Be- cause forest regeneration after wildfire is a long-term process, with a cycle of approximately 300 years, stream ecosystems are likely to respond similarly and shift in concert The Shoshone fire, later reclassified as part of the Snake River complex, seen from with temporal changes in plant com- Yellowstone Lake shore in late August. Photo: Jeff Henry, National Park Service. munity structure. Current understanding of stream ecosystem dynamics provides a rich river. The watersheds with small Gibbon, Lower Lamar, Madison, and base from which to postulate specific streams (first and second order) 1 com- Yellowstone rivers) are larger than changes in stream ecosystems as a monly burned entirely, whereas wa- fourth order, and thus they were af- result of forest changes after wildfire. tersheds with larger streams (fourth fected little by the fires in their lower Paramount to such understanding is order or larger) rarely did so. Cache reaches. the recognition of the crucial link Creek and Hellroaring Creek are the The impact of the fire in each drain- between the food available and the only watersheds in which the portions age also is regulated by factors af- feeding characteristics of the fauna in greater than third order received sub- fecting runoff and erosion. These fac- streams (Cummins 1974, Molles stantial burning. Most of the GYA tors include the physical make-up of 1982). It is also important to recog- streams that support a major sport the area (slope, aspect, elevation, gra- nize the influence of stream size as a fishery (Firehole, Gallatin, Gardner, dient, geology, and soil depth) and modifier of land-water interactions climatic variables (temperature, pre- (Minshall et al. 1985, Vannote et al. cipitation, insolation, and storm in- 1980). 1In stream terminology, the smallest un- tensity and frequency; Hydrology As- The effects of fire on aquatic eco- branched tributaries are first order. Two first- order streams join to form a second-order sessment Team 1988, Minshall and systems can be partitioned into imme- stream. The worlds largest rivers (e.g., Ama- Brock in press). Increases in flood diate effects that arise directly from zon or Mississippi) are tenth to twelth order. potential and sediment yield are the fire (e.g., increased temperature,

708 BioScience Vol. 39 No. 10 altered water chemistry, and abrupt change in food quality) and delayed impacts. Some of these delayed effects are primarily physical disturbances associated with increased runoff. These effects are likely to exert their maximal impact within the first one to four years after a fire. In addition, there are likely to be longer-term al- terations associated with the removal and eventual successional replacement of the riparian and terrestrial vegetative cover (Figure 2) and conse- quent alteration of food resources and retention capacity in the stream (Likens and Bilby 1982, Molles 1982).

Immediate effects. Except in small water bodies (first-order streams and small seeps), the high specific heat of water and replenishment from cool groundwater sources are likely to have prevented the heat from the Yel- lowstone fires from seriously damag- ing the aquatic biota. Cushing and Olson (1963) recorded a 10° C increase in temperature for a short time in a small, slow-moving stream after the burning of weeds that covered the stream and its banks. Trout (Onco- rhynchus mykiss, formerly Salmo gairdneri) in wire-mesh cages showed marked distress but did not die. Heat fracturing of the surfaces of rocks in first-order streams and incineration or scorching of exposed and shal- lowly submerged aquatic plants have been observed in GYA. 2 However, in most cases the fires are thought to have heated the water at most a few degrees (Albin 1979, Ice 1980). In larger streams, such as the Pirehole River, shading by dense clouds of smoke actually may have reduced water temperatures compared to those on a clear day (Ice 1980).3 Data from previous fire experience indicate that few, if any, adverse effects of the Yellowstone fires on water chemistry are to be expected (Johnson and Needham 1966, Schindler et at. 1980, Tiedemann et al. 1978, Wright 1976). Instead, algal growth may be temporarily stimulated to levels considered beneficial (Albin 1979, McColl and Grigal 1975). However,

2G. W. Minshall, 1988, unpublished observation. 3E. D. Koch, 1988, personal communication. Figure 1. a. Extent of 1988 GYA fires by drainage basin. b. Names of lakes and streams. Idaho State University, Pocatello. Data from Burned Area Survey Team 1988.

November 1989 709 Fire dead fish were observed in some sec- energy, can be expected to shift to Suspended ond- and third-order streams in sediments autotrophy until riparian communi- Yellowstone,4 which may have been kg/ho ties develop sufficiently to provide due to increases in certain ions from EQ/ha shade and adequate litter for a return ash entering the water (Cushing and to dependence on allochthonous (ter- Olson 1963). In these areas, the fire watts restrially derived) organic material may have burned more intensely and (Cummins 1974, Minshall 1978). thoroughly than did those fires previ- gC/m2 ously studied (Schindler et al. 1980). Long-term effects. Most of the long- In addition, increased pH may act gC/m2 term responses of Yellowstone directly on aquatic organisms or may aquatic ecosystems to the 1988 fires enhance the toxicity of certain sub- #/m2 (Figure 2) are likely to be closely stances, such as ammonia. In some allied with the recovery of the forest cases (e.g., Little Firehole River), sig- #/rn2 and understory vegetation (Figure 3; nificant fish mortality resulted from #/m2 Hynes 1975, Likens and Bilby 1982, accidental drops of ammonium phos- F W S S F W S S 2 5 10 50 100 300 Minshall et al. 1985, Molles 1982, phate, a fire retardant, into aquatic Normal Post fire Years after fire Vannote et al. 1980). Eventually, re- habitats.5 year year covery of the forest cover should result in increased shading of streams Midterm effects. The secondary con- Figure 2. Projected stream ecosystem re- and decreased runoff and input of sequences of fire on aquatic ecosys- sponses to a wildfire. These hypothetical nutrients, returning conditions in tems in GYA may be separated into trajectories illustrate anticipated changes these habitats to prefire levels. Even midterm and long-term effects. Mid- in key physical and biotic factors. Imme- within a region the size of the GYA, term effects are those exerting their diate and long-term effects are illustrated factors that regulate forest succession, maximal impact within the first few by using a logarithmic scale on the ab- scissa after the first postfire year. Actual such as elevation and climate, may years after a fire. Most of the adverse values depend on watershed size and cause streams to differ in their long- midterm delayed effects are likely to edaphic influences such as watershed as- term responses to disturbance from be due to increased sediment levels pect, slope, bedrock geology, severity of wildfire. and turbidity and erosion of stream fire damage (intensity and areal extent), channels (Minshall and Brock in and climatic factors such as precipitation ORGANIC DEBRIS DAMS. Dams of press). Delayed detrimental influences and temperature. organic debris, incorporating pieces on water chemistry generally are pre- of large wood, serve to retard the vented by chemicals becoming di- due to removal of overstory vegeta- downstream movement of particulate luted, being taken up by plants, and tion, and it gradually diminishes as organic matter and inorganic sedi- binding to soil, roots, and debris. this vegetation recovers (Figure 2). ments (Bilby 1981, Likens and Bilby Although moderately burned wa- Increased solar radiation reaching the 1982, Megahan 1982, Megahan and tersheds may show little or no change water after a fire can elevate summer Nowlin 1976). Consideration of the in stream chemistry, the combustion stream temperatures as much as 8- fate of wood in streams of forested of living and detrital plant biomass 10° C (Brown 1971, Burton and Lik- watersheds after large-scale distur- disrupts nutrient cycling, and the wa- ens 1973, Helvey 1973). These in- bances (wildfire or intensive logging) tershed can lose nutrients via stream creases may have a detrimental effect indicates that the diameter and mass runoff. Several studies report in- if they exceed critical threshold levels of woody debris, and hence its ability creased nutrient runoff after wildfires for resident invertebrate or fish pop- to help retain particulate organic mat- or logging and slash burning (Brown ulations. However, it is more likely ter, should increase progressively et al. 1973, McColl and Grigal 1975). that the slight (2-4° C) increases ex- with successional development of the Other researchers suggest that micro- pected in most cases (Albin 1979), forest (Likens and Bilby 1982, Molles bial uptake and absorption on soil coupled with the increases in light 1982). particles prevents nutrients from en- and nutrients, will increase primary Large amounts of woody debris tering aquatic systems (Johnson and and secondary production, including accumulate in old-growth forest Needham 1966). We expect that for growth of algae, invertebrates, and streams. Because of its high moisture several years after the Yellowstone fish (Murphy et al. 1986, Noel et al. content, most of this material remains fires, nutrient output (Figure 2) will 1986, Wallace and Gurtz 1986). The intact even after hot fires and is rap- increase, because terrestrial plant up- algae (and subsequent fauna) are ex- idly augmented by branches and take will be reduced and there will be pected to retard the downstream trunks brought down by the fire (Fig- increased mineralization and leaching movement of nutrients. ure 4). This material remains in place of elements accumulated in the water- These after-fire conditions in se- unless sufficiently high discharges shed. verely burned watersheds may result flush out all but the most stable Incident solar radiation initially in- in enhanced production of algae for pieces. creases sharply as a result of the fire two to six years, particularly in head- Although fallen fire-killed snags water streams. Low-order streams, continue to accumulate in streams for 4See footnote 1. which were formerly dependent on 20-25 years after a fire, the new sSee footnote 2. exogenous sources for their organic growth (through early to middle im-

710 BioScience Vol. 39 No. 10 mature forest; Figure 3) in the ripar- Old Growth Forest ian forest contributes little woody debris (Lyon 1984). Work by Golladay Mature Seral Forest and Webster (1988) suggests that in- a creased stream nitrogen levels, greater Immature Forest invertebrate abundance on woody rR substrates, and greater stream chan- Sapling nel instability may break down woody debris faster in the first few Herb/ ) years after a fire than at other times. Shrub As the forest matures and natural thinning occurs, additional woody material, increasing in diameter and 0 50 100 150 200 250 300 mass, accumulates in streams. This process accelerates as old-growth for- Years est conditions are attained, and stand- Figure 3. Succession in lodgepole pine (Pinus contorta) forest after wildfire (after Arno ing stocks of wood in the stream et al. 1985, Romme 1982). return to prefire levels. Retention of woody debris is a di- revegetates and erosion diminishes in 1973) are expected to contribute to rect function of the size of the material the years after a fire, the deposited the decline in autochthonous (within relative to the width and depth of the fine sediments in mountain streams the stream) production. stream. Smaller streams begin to re- are expected to be progressively Although the effect of enhanced cover to prefire levels of wood debris transported downriver by spring light levels in increasing primary pro- sooner than larger streams, and the runoff. This sequence was observed duction should persist 10-20 years frequency of debris dams decreases for the south fork of the Salmon River (Hansmann and Phinney 1973, Hawk- with increasing stream size (Likens in Idaho after cessation of logging ins et al. 1983, Murphy et al. 1986, and Bilby 1982). In the GYA, the activities (Megahan 1975, Megahan Newbold et al. 1980, Noel et al. pattern shown in Figure 4 is most et al. 1980). 1986), low nutrients may override the appropriate for headwater through stimulatory effect of increased light. third-order streams; significant woody NUTRIENT CYCLING. The initial nu- For example, in Carnation Creek, log- debris accumulations are absent in trient pulse is expected to be followed ging increased the amount of light most streams greater than fourth or- by a gradual decrease in nutrient loss reaching the water, but primary and der. from the watershed, concomitant secondary production remained lim- with high recovery of net photosyn- ited by low phosphorus (Culp and SUSPENDED SEDIMENTS. Suspend- thetic rates of terrestrial vegetation Davies 1983, Shortreed and Stockner ed-sediment yield (Figure 2) is nor- (Bormann and Likens 1979). Low nu- 1982). During later forest succession, mally positively correlated with water trient concentrations in the stream we expect nutrient export levels to discharge, and in the Rocky Moun- 5-10 years after the fire (Brown et al. drop below prefire levels as competi- tain region sediment yield follows the general pattern of snowmelt runoff (Bjornn et al. 1977). Mass movement (movement of a portion of the land Fire Woody Debris In Stream Channel surface, as in creep, landslide, or slip), wind, and rain are expected to produce an increase in sediment concentration in the months immediately after a fire. Snowmelt runoff is expected to carry abnormally high suspended-sediment loads, which decrease annually as the watershed becomes revegetated (Megahan et al. 1980). Unusually high spring runoff or intense summer thunderstorms after the first year could cause short- term departures from this decreasing trend. Increased sediment erosion into streams draining burned watersheds, FWSS FWSS 1 2 20 50 100 300 as well as the elevated suspended- Normal Post-fire sediment levels, invariably result in Year Years After Fire increased sedimentation in downriver Year depositional areas. As the burn site Figure 4. Postulated response of woody debris in lodgepole pine forest after wildfire.

November 1989 711 tion among plants for nutrients inten- nitrogen entering GYA streams from onstrated ability to distinguish be- sifies and nutrients accumulate in plant the watershed will be taken up rap- tween closely related aquatic and ter- biomass (Bormann and Likens 1979). idly and retained tightly by the system restrial plants, it seems quite feasible The changing nutrient and light re- (Grimm 1987, Newbold et al. 1983). that changes in secondary compounds gimes are expected to shift tempo- It also is likely that nitrogen will in terrestrial vegetation in response to rarily the benthic flora from diatoms markedly influence the rate of litter fire could result in changes in the and moss to green algae, with brief decomposition (Meyer and Johnson quality of allochthonous leaf litter (2- to 5-year) development of fila- 1983). The nitrogen effects on both entering streams, which would affect mentous algal mats (e.g., Cla- primary producers and litter decom- its use by aquatic detritivores. Be- dophora). Albin (1979) found no dif- position can control secondary pro- cause allochthonous detritus is a pri- ference between attached algae duction in streams (Grimm 1988). mary determinant of energy and or- accumulations in unburned sites and Measurements from Cache Creek ganic-matter dynamics in streams those burned 36 and 45 years previ- in YNP shortly after the 1988 fire (Hynes 1975), any significant changes ously, thus supporting the pattern indicate a progressive decline in nitro- in its quality or quantity are likely to shown for recovery of primary pro- gen concentration with distance exert profound effects throughout the duction in Figure 2. downstream6 (Figure 5). The greatest stream ecosystem. Streams should be efficient at re- change (sixfold) occurred between taining nutrients after fires, and the first- and second-order sites, and then STREAM FAUNA. Responses of the degree of response depends on stream a twofold decrease was observed at benthic invertebrates to the aftermath order (Grimm 1987, Meyer 1980, each of the subsequent shifts in of the Yellowstone fires are expected Meyer and Likens 1979, Minshall et stream order, continuing through the to vary depending on the degree of al. 1983b, 1985, Newbold et al. confluence of Cache Creek with the sedimentation (Hawkins et al. 1983) 1982, 1983, Vannote et al. 1980). Lamar River. These results indicate and streambed movement that oc- With increasing stream order, the ri- substantial and differential uptake of curs. Increased flows, streambed ero- parian canopy is likely to have a nitrogen along the course of the sion, and high suspended-sediment progressively declining effect on in- stream, even though October is a pe- concentrations for major snowmelt or stream ecosystem dynamics (Vannote riod of declining light and tempera- rainfall runoff pulses in the first year et al. 1980). Most nutrient uptake ture. The most significant variation in after the fire may bring about massive and growth of algae and other orga- this downstream pattern should occur invertebrate drift out of streams nisms is expected to occur in first- and as a result of the entrance of tributar- draining the burned areas. Deposition second-order streams, and little effect ies draining burned watersheds. We of fine sediments also may cause di- of wildfires will be seen with respect expect the lower-order, nutrient- minished invertebrate standing crops to light and nutrient dynamics in laden tributaries to stimulate biotic in those habitats affected. For exam- streams larger than approximately production in the receiving streams ple, heavy accumulations of fine sed- fourth order. A major exception to for some distance downstream of iments will eliminate the mixed grav- this generalization may be the influx their confluence. This biostimulatory el-cobble substrate preferred by of nutrients from tributaries into response should significantly retard endemic species, causing recovery to streams that are fourth order or larger the downstream flush of nitrogen. be delayed until sediments are eroded (Minshall et al. 1985). However, severely decreased light lev- and the benthos is recolonized. The two major factors affecting the els, due to suspended sediments dur- Recolonization of these depopu- pattern of dissolved nutrient concen- ing storm runoff, could counteract lated areas will depend on the extent trations in streams are water-borne this nutrient enrichment effect. of fire-induced disruption of upstream transport and biotic uptake and re- headwater areas, which will serve as lease (Minshall et al. 1983b, New- ORGANIC LITTER INPUT. Organic seed sources. From previous work bold et al. 1982). Biotic processes litter input to the land and stream, conducted on the Teton River in Idaho appear to be more important in regu- including export to and retention by (Minshall et al. 1983a), we predict lating phosphorus, nitrogen, and po- the flood plain adjacent to the stream that recovery may take three years or tassium, whereas discharge (volume during runoff, will be elevated during more, depending on the severity and of water per unit time) and related the first year after the fire, but then it extent of scouring due to runoff. geologic processes are thought to ex- will decline as the forest community Benthic invertebrates can be di- ert the dominant regulatory force on returns (Figure 2). There is experi- vided into groups on the basis of their calcium, magnesium, and sodium mental evidence (Otto and Svensson feeding behaviors. These categories ions (Henderson et al. 1978). In 1981) that aquatic herbivores may be are called functional feeding groups GYA, physical transport is most im- sensitive to differences in secondary and are expected to respond differ- portant during spring runoff and spo- compounds in vascular plants. Thus ently to the effects of fire. They in- radic summer rain storms, and biotic far, the topic has been examined only clude shredders, which consume uptake peaks at midsummer. from the perspective of the coevolu- streamside, riparian litter after it en- In streams in the western United tion of aquatic grazing invertebrates ters the stream; collectors, which use States, the most important nutrient versus aquatic and riparian plants. small particles of organic matter in regulating the primary producers of- Given the aquatic invertebrates dem- the water; and grazers (scrapers), ten is nitrogen (Grimm and Fisher which eat attached organic matter, 1986). Therefore, it is expected that 6See footnote 2. especially algae.

712 BioScience Vol. 39 No. 10 During recovery from a fire, shred- 25 due primarily to the size of the water- der populations (Figure 2) are ex- (a) shed burned and the intensity of the pected to be almost entirely absent due 20 fire. However, the chance occurrence to the destruction of quality leaf litter 15 of intense summer storms, common sources by the fire. Grazer density z0 in the Yellowstone area, also is a should increase after fire, following a 05 10 factor. pattern similar to that of primary pro- In Figure 6, some potential reduction, on which they directly feed z0 sponses to different degrees of distur- (Murphy et al. 1986, Noel et al. 1986, bance resulting from fire are illus-

Wallace and Gurtz 1986). 1st 2nd South 3rd 4th Lamar trated for biotic features such as Once a productive autotrophic Cache Creek abundance and richness. Three alter- community becomes established, native trajectories are illustrated: amounts of high-quality benthic organic matter will be elevated, thereby 50 Those streams that because of the enhancing collector populations, al- (b) smaller fire-affected catchments, though some species may be elimi- 40 greater water retention by the sur- nated due to the higher summer tem- 30 rounding watershed, or sheer peratures. Higher levels of transported rn chance avoid high intensity, scour- organic material from both terrestrial z 20 ing discharges, will begin the recov- (rapidly growing herbaceous and ery process relatively quickly. In shrubby plants) and in-stream sources 10 such cases, the stream ecosystems (sloughed periphyton and invertebrate are expected to return relatively feces) will bring about increased den- 1st 2nd South 3rd 4th Lamar rapidly to prefire conditions. sities of filter feeders (a subcategory of Cache Creek In those streams in which the wa- collectors), most notably caddisflies tershed becomes heavily eroded and (Hydropsychidae, Brachycentridae) Figure 5. Nitrogen concentrations (mg/1) the bed severely scoured, recovery and blackflies (Simuliidae). Collector in Cache Creek, YNP, approximately two weeks after its watershed burned in 1988. will be delayed and may ultimately densities consequently will exceed pre- a. Nitrite plus nitrate. b. Total dissolved follow a different trajectory alto- fire levels during the intermediate post- inorganic nitrogen. gether. fire years due to elevated levels of In severe cases, such as when re- endogenous organic material. peated disturbances of the stream As postfire plant regrowth occurs detritus standing crop in the conifer channel occur over a long time, and the canopy closes, we expect to streams to this difference in retention new, lower levels for abundance see a shift in the predominant food capacity. Likewise, Rounick and and richness may be established. from algae to terrestrial leaves and Winterbourn (1983) found that en- needles (Figure 2). High quality (fast hanced physical stability of the Research needs decomposition) herbaceous litter, stream bed resulted in increased re- consumed first by shredders and then tention of allochthonous inputs and and opportunities by collectors, should gradually be re- standing crops of shredders and ele- Although we can speculate on the placed by lower quality (slow decom- vated rates of leaf breakdown. Thus, effects of fires on aquatic ecosystems, position) deciduous leaves, which in as algal production declines due to insufficient specific information is turn will be supplanted by even lower reduced light and nutrient availability available to reliably predict their ef- quality conifer needles and twigs (Fig- and as detrital standing crops increase fects over the array of conditions ure 3). For example, Molles (1982) with increasing litter and deadfall ac- found in GYA. Conditions in aquatic postulated that, during postfire forest cumulations, a shift from low to high habitats during or immediately after a succession, the recovery of Tri- shredder:grazer ratios is to be ex- fire have been documented in only a choptera shredders would parallel the pected (Molles 1982). few cases. Little is known of the fac- accumulation of conifer wood and tors responsible for the observed fish forest litter in streams. Over time, the Potential responses to different mortalities, the extent of that mortal- shredder populations are expected to ity, or whether other groups of orga- recover, whereas those of the grazers degrees of disturbance nisms also were affected. will decline to prefire levels. Fires of a magnitude such as burned Previous studies often differ mark- Further, we expect that the number during 1988 in GYA can have sweep- edly in climatic and topographic con- of debris dams will increase progres- ing effects on the ecology of streams. ditions from those found in GYA and sively during the first 25 years (Figure The extent of the near-term effects of the other large national parks and 4), resulting in increased retention fire on stream ecosystems and the wilderness areas of the northern capacity for allochthonous food re- rates of return to prefire conditions Rockies. Reports of "no adverse ef- sources. For example, Molles (1982) are dependent largely on the degree of fect" in previous studies commonly found five times the number of logs in disruption of the watershed and are clouded by an inadequate data- conifer forest streams as compared to stream channel in the first few years base or by unsatisfactory sampling, aspen forest streams and attributed after fire. The difference (for a given which may have begun after the dis- the order of magnitude difference in environmental region) appears to be appearance of organisms killed by the

November 1989 713 fire. Likewise, the effect of fire retar- Fire Culp, J. M., and R. W. Davies. 1983. An as- dants on aquatic habitats, the down- Pref ire sessment of the effects of stream bank clearcutting on macroinvertebrate communities in stream extent of the effect, and even a managed watershed. Can. Tech. Rep. Fish. the extent of the problem are poorly 7 Aquat. Sci. 1208. known. Cummins, K. W. 1974. Structure and function The near-term effects of fire are of stream ecosystems. BioScience 24: 631- 0 Ar 641. probably the best described, but these Cushing, C. E., and P. A. Olson. 1963. Effects studies have concentrated on chemi- of weed burning on stream conditions. ii i cal conditions in the water. Informa- 1 2 3 10 1()01 300 Trans. Am. Fish. Soc. 92: 303-305. tion on the effects of fires of different Time (log years) Golladay, S. W., and J. R. Webster. 1988. Ef- fects of clear-cut logging on wood break- degrees of severity on the composi- down in Appalachian mountain streams. tion and productivity of algae, inver- Figure 6. Expected changes in total abun- Am. Midl. Nat. 119: 143-155. tebrates, and fish are largely undocu- dance (numbers or biomass) or species Grimm, N. B. 1987. Nitrogen dynamics during Ecology 68: mented. Little also is known of the richness after wildfire (from Minshall and succession in a desert stream. internal functional responses of 1157-1170. Brock in press). Three possible recovery . 1988. Role of macroinvertebrates in aquatic ecosystems to fire. For exam- trajectories are shown: circles and dashed nitrogen dynamics of a desert stream. Ecol- ple, there is considerable evidence lines represent moderate impact and rapid ogy 69: 1884-1893. that biological processing and physi- return to prefire conditions; triangles rep- Grimm, N. B., and S. G. Fisher. 1986. Nitro- cal retention may serve to retard the resent relatively severe impact, eventually gen limitation in a Sonoran desert stream. J. downstream movement of nutrients returning to prefire levels (dashed lines) or North Am. Benthol. Soc. 5: 2-15. attaining a new (lower) equilibrium level Hansmann, E. W., and H. K. Phinney. 1973. and their loss from a watershed and Effects of logging on periphyton in coastal that these processes may vary with (broken horizontal line). The actual pattern of recovery will be determined largely streams of Oregon. Ecology 54: 194-198. stream size (e.g., Grimm 1987, Min- Hawkins, C. P., M. L. Murphy, N. H. Ander- by the extent of disturbance of the water- son, and M. A. Wilzbach. 1983. Density of shall et al. 1983b, Newbold et al. shed and stream channel from runoff in 1982, 1983), but these ideas have not fish and salamanders in relation to riparian the first few years after the fire. canopy and physical habitat in streams of the been tested. northwestern United States. Can. J. Fish The lack of information concerning Aquat. Sci. 40: 1173-1185. the effects of fire on aquatic ecosys- Fish Game 65: 216-238. Helvey, J. D. 1973. Watershed behavior after tems is especially important for large- Arno, S. F., D. G. Simmerman, and R. E. forest fire in Washington. Pages 403-422 in Keane. 1985. Forest succession on four hab- Proceedings of the Irrigation and Drainage scale and long-term situations. Yel- itat types in western Montana. US Forest Division Specialty Conference. American So- lowstone offers some especially Service Intermountain Forest Range Experi- ciety of Civil Engineers, Washington, DC. exciting opportunities for such re- ment Station, General Technical Report Henderson, G. S., W. T. Swank, J. B. Waide, search. For example, virtually noth- INT-177, Ogden, UT. and G. C. Grier. 1978. Nutrient budgets of ing is known of the sequence of events Bilby, R. E. 1981. Role of organic debris dams Appalachian and Cascade region water- in regulating the export of dissolved and sheds: a comparison. For. Sci. 24: 385-397. that may occur in aquatic ecosystems particulate matter from a forested water- Hydrology Assessment Team. 1988. Water re- after the first year or two after a fire, shed. Ecology 62: 1234-1243. source assessment. Greater Yellowstone whether these sequences may differ Bjornn, T. C., M. A. Brusven, M. P. Molnau, Post-fire Resource Assessment and Recovery from one situation to another, or and J. H. Milligan. 1977. Transport of gra- Program. US Park Service and US Forest what factors would be responsible for nitic sediment in streams and its effects on Service, Yellowstone, WY. insects and fish. Office of Water Research Hynes, H. B. N. 1975. The stream and its such differences. and Technology Research, Technical Com- valley. Verhandlungen Internationalen Rarely in the history of modern pletion Report Project B-036-IDA, Moscow, Vereinigung Limnologie 19: 1-15. ecology has the opportunity been ID. Ice, G. G. 1980. Immediate stream temperature available to examine the effects of fire Bormann, F. H., and G. E. Likens. 1979. Pat- response to a prescribed burn. National Coun- on stream habitats in watersheds tern and Process in a Forested Ecosystem. cil of the Paper Industry for Air and Stream Springer-Verlag, New York. Improvement Special Report, New York. larger than third order or to compare Brown, G. W. 1971. Water temperature in Johnson, C. M., and P. R. Needham. 1966. responses of stream ecosystems to small streams as influenced by environmental Ionic composition of Sagehen Creek, Califor- mosaic burns versus nearly complete, factors. Pages 175-181 in J. T. Krygier and nia, following an adjacent fire. Ecology 47: intense burns. Because of the scale of J. D. Hall, eds. Forest Land Uses and Stream 636-639. the 1988 fires and the variety of Environment. Oregon State University, Cor- Likens, G. E., and R. E. Bilby. 1982. Develop- vallis. ment, maintenance, and role of organic- stream types and conditions repre- Brown, G. W., A. R. Gahler, and R. B. Mar- debris dams in New England streams. Pages sented, GYA could serve as an excel- ston. 1973. Nutrient losses after clear-cut 122-128 in F. J. Swanson, R. J. Janda, T. lent natural laboratory for testing logging and slash burning in the Oregon Dunne, and D. N. Swanston, eds. Sediment ideas and for supplying much-needed coast range. Water Resour. Res. 9: 1450- Budgets and Routing in Forested Drainage information for evaluating current 1453. Basins. US Forest Service Pacific Northwest Burned Area Survey Team. 1988. Preliminary Forest Range Experiment Station, General fire management policies, predicting burned area survey of Yellowstone National Technical Report PNW-141, Portland, OR. the effects of fire, and planning re- Park and adjoining forests. Greater Yellow- Lyon, L. J. 1984. The Sleeping Child burn: 21 source management strategies for stone Post-fire Resource Assessment and Re- years of postfire change. US Forest Service stream ecosystems. covery Program, US Park Service and US Research Paper INT-330, Washington, DC. Forest Service, Yellowstone, WY. McColl, J. G., and D. F. Grigal. 1975. Forest Burton, T. M., and G. E. Likens. 1973. The fire: effects on phosphorus movement to References cited effect of strip-cutting on stream temperatures lakes. Science 185: 1109-1111. Albin, D. P. 1979. Fire and stream ecology in in the Hubbard Brook Experimental Forest, Megahan, W. F. 1975. Sedimentation in rela- some Yellowstone Lake tributaries. Calif.- New Hampshire. BioScience 23: 433-435. tion to logging activities in the mountains of

714 BioScience Vol. 39 No. 10

central Idaho. US Agric. Res. Serv. ARS-S Minshall, G. W., and J. T. Brock. In press. macrophytes growing in or close to water 40: 74-82. Anticipated effects of forest fire on Yellow- reduce their consumption by aquatic herbi- 1982. Channel sediment storage be- stones stream ecosystems. In B. Keiter and vores? Hydrobiologia 78: 107-112. hind obstructions in forested drainage basins M. Boyce, eds. Greater Yellowstones Fu- Romme, W. H. 1982. Fire and landscape diver- draining the granitic bedrock of the Idaho ture: Man and Nature in Conflict? University sity in subalpine forests of Yellowstone Na- Batholith. Pages 114-121 in F. J. Swanson, of Arizona Press, Tucson. tional Park. Ecol. Monogr. 52: 199-221. R. J. Janda, T. Dunne, and D. N. Swanston, Minshall, G. W., K. W. Cummins, R. C. Peter- Rounick, J. S., and M. J. Winterbourn. 1983. eds. Sediment Budgets and Routing in For- sen, C. E. Cushing, D. A. Bruns, J. R. Sedell, Leaf processing in two contrasting beech ested Drainage Basins. US Forest Service and R. L. Vannote. 1985. Developments in forest streams: effects of physical and biotic Pacific Northwest Forest Range Experiment stream ecosystem theory. Can. J. Fish. factors on litter breakdown. Arch. Hydro- Station, General Technical Report PNIX/- Aquat. Sci. 42: 1045-1055. biol. 96: 448-474. 141, Portland, OR: Minshall, G. W., R. C. Petersen, K. W. Cum- Schindler, D. W., R. W. Newbury, K. G. Beaty, Megahan, W. F., and R. A. Nowlin. 1976. Sed- mins, T. L. Bott, J. R. Sedell, C. E. Cushing, J. Prokopowich, T. Ruscznski, and J. A. Dal- iment storage in channels draining small and R. L. Vannote. 1983b. Interbiome com- ton. 1980. Effects of a windstorm and forest forested watersheds in the mountains of cen- parison of stream ecosystem dynamics. Ecol. fire on chemical losses from forested water- tral Idaho. Paper presented at the third Fed- Monogr. 52: 1-25. sheds and on the quality of receiving streams. eral Inter-agency Sedimentation Conference, Molles, M. C. Jr. 1982. Trichopteran commu- Can. J. Fish. Aquat. Sci. 37: 328-334. Denver, Colorado, 22-25 March 1976. Sed- nities of streams associated with aspen and Shortreed, K. S., and J. G. Stockner. 1982. The imentation Committee, Water Resources conifer forests: long-term structural change. impact of logging on periphyton biomass Council, Washington, DC. Ecology 63: 1-6. and species composition in Carnation Creek: Megahan, W. F., W. S. Platts, and B. Kuleszna. Murphy, M. L., J. Heifetz, S. W. Johnson, a coastal rain forest stream on Vancouver 1980. Riverbed improves over time: South K. V. Koski, and J. F. Thedinga. 1986. Ef- Island, British Columbia. Pages 197-209 in Fork Salmon River. Pages 380-395 in Pro- fects of clear-cut logging with and without G. F. Hartman, ed. Proceedings of the Car- ceedings for Symposium on Watershed Man- buffer strips on juvenile salmonids in Alas- nation Creek Workshop: A Ten Year Re- agement 1980. vol. 1. American Society of kan streams. Can. J. Fish. Aquat. Sci. 43: view. Pacific Biological Station, Nanaimo, Civil Engineers, Washington, DC. 1521-1533. British Columbia, Canada. Meyer, J. L. 1980. Dynamics of phosphorus Newbold, J. D., J. W. Elwood, M. S. Schulze, Tiedemann, A. R. C. E. Conrad, J. H. Dieter- and organic matter during leaf decomposi- R. W. Stark, and J. C. Barmeir. 1983. Con- ich, J. W. Hornbeck, W. F. Megahan, L. A. tion in a forest stream. Oikos 34: 44-53. tinuous ammonium enrichment of a wood- Viereck, and D. D. Wade. 1979. Effects of Meyer, J. L., and C. Johnson. 1983. The influ- land stream: uptake kinetics, leaf decompo- fire on water: a state-of-knowledge review. ence of elevated nitrate concentration on rate sition, and nitrification. Freshwater Biol. 13: US Forest Service General Technical Report of leaf decomposition in a stream. Freshwa- 193-204. WO-10, Washington, DC. ter Biol. 13: 177-183. Newbold, J. D., D. C. Erman, and K. B. Roby. Tiedemann, A. R., J. D. Helvey, and T. D. An- Meyer, J. L., and G. E. Likens. 1979. Trans- 1980. Effects of logging on macroinverte- derson. 1978. Stream chemistry and water- brates in streams with and without buffer shed nutrient economy following wildfire port and transformation of phosphorus in a and fertilization in eastern Washington. J. forest stream ecosysytem. Ecology 60: strips. Can. J. Fish. Aquat. Sci. 37: 1076- 1085. Environ. Qual. 7: 580-588. 1255-1269. Vannote, R. L., G. W. Minshall, K. W. Cum- Minshall, G. W. 1978. Autotrophy in stream Newbold, J. D., R. V. ONeill, J. W. Elwood, mins, J. R. Sedell, and C. E. Cushing. 1980. ecosystems. BioScience 28: 767-771. and W. VanWinkle. 1982. Nutrient spiral- The river continuum concept. Can. J. Fish. Minshall, G. W., D. A. Andrews, and C. Y. ling in streams: implications for nutrient Aquat. Sci. 37: 130-137. Manuel-Faler. 1983a. Application of island limitation and invertebrate activity. Am. Nat. Wallace, J. B., and M. E. Gurtz. 1986. Re- biogeographic theory to streams: macroin- 120: 628-652. sponse of Baetis mayflies (Ephemeroptera) to vertebrate recolonization of the Teton River, Noel, D. S., C. W. Martin, and C. A. Federer. catchment logging. Am. Midl. Nat. 115: Idaho. Pages 279-297 in J. R. Barnes and 1986. Effects of forest clearcutting in New 25-41. G. W. Minshall, eds. Stream Ecology: Appli- England on stream macroinvertebrates and Wright, R. F. 1976. The impact of forest fire on cation and Testing of General Ecological periphyton. Environ. Manage. 10: 661-670. the nutrient influxes to small lakes in north- Theory. Plenum Press, New York. Otto, C., and B. S. Svensson. 1981. How do eastern Minnesota. Ecology 57: 649-663.

November 1989 715 Drought, Fires, and Large Mammals Evaluating the 1988 severe drought and large-scale fires

Francis J. Singer, William Schreier, Jill Oppenheim, and Edward 0. Garton

ellowstone National Park is premise that, over a period of years, renowned for its fauna of di- native ungulate populations would y verse and numerous large Fires directly killed few regulate their own birth and death mammals. There are hundreds of elk, but the fires and rates in relation to available winter black and grizzly bears (Ursus ameri- food and population size. A natural canus and Ursus arctos) that roam the drought increased the regulation experiment has continued area, and coyotes (Canis latrans) and next winters die-off for the park elk and bison herds from mountain lions (Felis concolor) as 1968 to the present. Cayot et al. well, but ungulates far outnumber (1979), Despain et al. (1986), and Houston (1982) reported the experi- them. five times as many elk as all other Approximately 2500 bison (Bison ment to be largely successful, al- types of ungulates combined. though Beetle (1974) and Chase bison) inhabit the park in three herds Since the designation of Yellow- (Meagher 1973, 1988). There are also (1986) have argued that elk numbers stone National Park (YNP) in 1871, are still increasing and the elk are approximately 2500 mule deer elk management there has been con- (Odocoileus hemionus), 400-500 diminishing the vegetation. troversial. Early park managers held At the time of the 1988 drought pronghorn antelope (Antilocapra an almost agricultural philosophy for americana), 250-400 bighorn sheep and fires in Yellowstone, studies of ungulate management, which in- the northern range were reevaluating (Ovis canadensis), and 200 moose cluded artificial feeding of elk, bison, (Alces alces) on Yellowstones north- the success of the natural regulation and pronghorn antelope; elimination experiment. Extensive burning in ern winter range. of wolves (Canis lupus); and near In winter, four herds of elk (Cervus 1988 occurred on five out of the seven elimination of mountain lions (Weav- elk summer ranges. All four of the elk elaphus), approximately 22,500 indi- er 1978). viduals in 1988, inhabit the park and winter ranges had from 2-50% of By 1911, some concern was ex- their areas burned. No previously adjacent areas that are part of the pressed about the increasing number northern winter range (Figure 1). Elk published study has documented of elk. This concern grew after a large burning effects on such a large scale from five other herds migrate into the winterkill of elk in the park in 1919- park each summer, increasing the across the entire year-round ranges of 1920 (Cahalane 1941, Skinner 1928) several large elk herds. population to approximately and intensified further during the se- 31,000. 1 This article focuses on elk, vere drought of 1919-1936. 2 Artifi- because they are overwhelmingly the cial reductions of park elk, bison, and Drought effects dominant park ungulate both in num- pronghorn were then conducted; on grasslands ber and total mass. In early 1988 on however, the killings were terminated the northern winter range, there were Summer weather conditions in 1988 in 1968 after a public outcry and significantly reduced grassland pro- congressional hearings. ductivity, although earlier in the year Francis J. Singer is a research ecologist, Cole (1971) and Houston (1976) there was no water shortage. We William Schreier is a resource manage- proposed experimental management counted and measured height of veg- ment park ranger, and Jill Oppenheim is a of the elk and bison based on the etative leaves and reproductive stalks biological technician with the National for three key elk forages: bluebunch Park Service, Yellowstone National Park, 1F. J. Singer, 1989, manuscript submitted. (Agropyron spicatum), WY 82190. Edward 0. Garton is a pro- wheatgrass 2M. Coughenour and F. J. Singer, 1989, manu- (Koeleria cristata), fessor of wildlife resources at the College script submitted. Colorado State University, prairie junegrass of Forestry, Wildlife and Range Science, Fort Collins, and Yellowstone National Park, and Idaho fescue (Festuca idahoen- University of Idaho, Moscow, ID 83843. WY. sis). Measurements were taken on all

716 BioScience Vol. 39 No. 10 Table 1. Effects of the 1988 drought on grasses on Yellowstones northern range. The warmer-site grasses were reduced more than grasses growing in the Lamar Valley, which is located at the cooler, upper reaches of the winter range. Percent change over 1986 and 1987 Leaf Flower Tallest Tallest Grass species number number leaf flower Warm-site grasses Agropyron spicatum —24 —12 —28 —25 Koeleria cristata —48 —54 +23 —6 Lamar Valley Agropyron smithii +74 —23 —12 Festuca idahoensis +100 +18 +25 Poa spp. +77 —7 the grass clumps within ten randomly where wide, fast-moving fire fronts located one-meter-square plots. This occurred (Figure 2). Helicopters were data was compared to similar mea- used to survey transects 0.4 to 0.6 km surements gathered in 1986 and apart, and in six of the burned areas 1987. an additional 694 km were surveyed The low winter snowpack during by foot and horseback. Trachea and the winter of 1987-1988 set the stage muscle samples were collected to de- for dryer than normal conditions in termine whether the animals had died early 1988 (Table 1). Precipitation of smoke inhalation. during the winter of 1987-1988 was A total of 261 large mammals were only 31% of normal. However, April found dead in the areas of four of the and May 1988 precipitation was 1988 fires within Yellowstone Na- 168% of normal, and as a result grass tional Park: 246 elk, 2 moose, 4 mule growth in the cooler Lamar Valley deer, and 9 bison. This count repre- was at least as good as in 1986 or sents approximately 1% of the 1987 (Table 1). 31,000 elk summering within YNP The months of June, July, and Au- and an even lower fraction of the gust were among the driest on record other animals. None of 68 radiocol- for the Yellowstone area (averaging lared park elk died in the fires. Two 36% of normal precipitation). Tem- radiocollared grizzly bears in the park peratures were also elevated. (June are believed to have been killed by the temperatures were 5° C above nor- fires (Blanchard and Knight in press); mal, and July was 0.5° C above nor- the proportion of the grizzly bear mal.) Above-average winds also con- population possibly killed is esti- tributed to the dryness. Warm-site mated at 0.5-1%. An additional 137 grasses were significantly reduced by large mammals were killed just out- the 1988 drought (Table 1). Summer side of the park (89 elk, 10 moose, 6 range grassland production values black bear, and 32 mule deer).4 were reduced more than 50%. 3 Typ- We suspect the count includes all ically elk still find green forbs and the large groups of carcasses in the grasses in forest stands in September, park. The more than 10,000 fire and frequently late rains stimulate fall fighters, who accumulated 18,000 greening in the open grasslands. Au- flight hours and more than 1000 km gust and September of 1988, how- of foot travel, reported carcasses. In ever, were so dry that elk ate primar- addition, the large carcass piles were ily dried grasses. especially noticeable as they were visited by hundreds of scavenger birds Fire mortality and animals. Small groups of one to three carcasses may have gone unde- Immediately after the fires began to tected. subside, we surveyed fire-caused large There is almost no published docu- mammal deaths in 15 burned areas mentation of large mammals dying in

3E. Merrill and L. Wallace, 1989, personal 4T. Kilough, G. Roby, D. Tyers, 1988, personal communication. University of Wyoming, communication. Wyoming Game and Fish De- Elk (top) grazing in a burned forest. Elk Laramie, and University of Oklahoma, Nor- partment, Cody and Jackson, WY, and US (center) and bison (bottom) carcasses man. Forest Service, Gardiner, MT. found after the fire.

November 1989 717 cooler, mature forests on north and east slopes (Geist 1982) where fires burned faster, and perhaps the soli- CUSTER tary nature of mature bull elk in sum- NATIONAL FOREST mer, may have made bulls more vulnerable than cow-calf-yearling bull GALUITIN NATIONAL groups. FOREST 4 Trachea evidence suggests smoke in- rooke City • GSTdIner halation killed all or nearly all the fire-killed elk before they were burned by the flames. Twenty-five of 30 tra- 0 cheae examined contained caked soot below the level of the vocal cords (Moylan 1980, Walker et al. 1981). Hebgen Lake 14 Four tracheae were completely burned, precluding examination, and / • in another specimen, the trachea lining was absents Dense, low-lying smoke -14):9- • 0 )1 West Nellowstoneg was observed in front of several fires at the approximate time of the elk SHOSHONE NATIONAL deaths.6 One group of elk south of the r// FOREST park was killed when caught between

Old Faithful the Mink fire and a man-started back TARGHEE burn. Flames burned or singed most NATIONAL FOREST of the elk carcasses, especially ears,

Shoshone hooves, teeth, hides, and shattered ant- o lers. The bodies of some suffocated elk in small wet sites, however, were un- Lewis L. 0 burned. Topography and aspect signifi- I YELLOWSTONE cantly influenced the distribution of o 4 0 lus Itsmosat 4f4 fire-killed elk (Kolmogorov-Smirnov / W 1/Y Scala ••• / /HY MOW ./.W7 /Zr/./ l/ • test, p = 0.03, 0.04; Figures 3 and 4), REFERENCE MOP RIDGES-TETON but slope did not (p = 0.42; Figure 5). NATIONAL FOREST Sixteen (41%) fire-burned elk groups, GRAND TEbN , NATIONAL PARK L.., and 47% of the elk carcasses, were on ••■ Northern Herd mountain sides or ridgetops, 10 (26%) were on level or rolling terrain, and 13 (33%) were in creek bottoms. Most of the dead elk in the creek Figure 1. Winter range for the northern Yellowstone elk herd. bottoms were lying in water or were only 2-3 m from the water, suggest- either wildfires or prescribed burns in tral harem bull and several competing ing they sought the water or the low- North America (Bendell 1974, Buck- large bulls in satellite positions. The est local point, where the smoke ley 1958, Howard et al. 1959, Leege only exception was a large group of would have been less thick. 1968), although large mammals, in- 146 elk, found clustered in a 20-meter The only known injured survivors cluding elephants (Loxondonta afri- circle, which we speculate consisted of the fires, a mature bull elk and cana) and antelopes have occasionally of several harem groups that had bison, sought refuge in the Lava been observed to be killed by fires in bunched together in panic. Creek bottom. The bison died the day Africa (Komarek 1969). Chew et al. Sex and age ratios of the fire-killed after the fire, but the bull elk survived (1958) reported a fire-killed black- elk were 36 calves, 11 yearling bulls, for 42 days before it was found and tailed deer (Odocoileus hemionus) in and 63 adult bulls per 100 cows. The disposed of humanely. The bull elk California. In general, elk and other calf and yearling bull-to-cow ratios had severely burned hide on the hips large, mammals have proved adept at did not depart significantly from the and lower legs, and its hooves were avoiding flames and moving around herd ratios as a whole; however, fire fronts. more adult bulls died in the fires than Groups of carcasses contained 1 to expected based on the herd ratio (chi- 5S. P. French, 1989, personal communication. 146 dead elk. Generally the sizes, sex square test, X2 = 25.63, p < 0.002). Yellowstone Grizzly Foundation, Evanston, Cow-calf groups tend to use open WY. and age composition, and locations of 6R. Barr, 1988, personal communication. Yel- dead elk were suggestive of typical habitats more than bulls do (Geist lowstone National Park, WY. rutting group aggregations of cows, 1982, Lieb and Marcum 1979). G. Roby, 1988, personal communication. Wy- calves, and yearling bulls, with a cen- Therefore, the greater preference for oming Game and Fish Department, Jackson.

718 BioScience Vol. 39 No. 10 Storm Creek

TAISTSR NATIONAL Hellroaring FOREST

GALLATIN NATIONAL FOREST Gardiner Cooke City /49/eSWASSeakWAY/49449.4PSW 40/A/17 ■-•nn • • • • • • •

Cover types

Ilebgen lake Figure 4. Cover types where fire-killed elk carcasses were located during 1988. Won. Lake • O il We: the estimated rates of fire spread were Nellowstone 4.1-6.9 km/hr. 8 No large-mammal

SHOSHONE • mortality was observed in fires where NATIONAL FOREST slower rates of fire spread were esti-

‘4. mated and the animals could move • • Old Faithful TARCIREE.. out of the way. Fire fronts exceeding NATIONAL FOREST. 2 km in width and total fire runs of 6-21 km in a day were characteristic Shoshone La of the sites where large-mammal mortality occurred. f.rwir la Snake River Scavenging activity on the fire- • • artlake killed carcasses was extensive, and YELLOWSTONE nearly all the carrion was consumed lfdtdoei Paul by 1 December 1988 (Figure 6), 82 4:401VASY4.9400f4ekkikkbril7Str/, ,45971419//7/17///21,1//iY/1Y/YAY days after the last known fire mortal- :FEN (it gp ity. At least 600 ravens (Corvus co- BRIOGER•TETON : Huck NATIONAL PONAST rax), 30 bald eagles (Haliaeetus leu- --- GRAND T cocephalus), and a large number of NATIONAL PARK L. grizzly and black bears and coyotes (Canis latrans) used the carcasses. Ej 1988 Fire Fronts The ungulate contribution to the grizzly bear diet increased to 27% in 1988 from an average 8% in 1979- Figure 2. Major fronts of fire complexes in Yellowstone National Park in 1988. 1987 (Blanchard and Knight in press). Raven activity was observed at 54% of the carcasses, coyote activity partially burned off. It had not moved Seven of the fire-killed groups of at 29%, grizzly bear activity at 27%, more than 30 m since the fire and was elk (18%), and 30% of the elk car- surviving on greening streamside casses, were found in open grass- sedges (Carex spp.). lands, usually on the edge of a forest 8P. Perkins, 1989, personal communication. (Figure 5). The remaining 33 groups Yellowstone National Park, WY. (82%) were in conifer forest, including 10 in whitebark pine stands (Pi- 14- a VA nus albicaulis), 8 in mature lodgepole 2 12 pine stands (P. contorta), 7 in mid- 10 - co - co aged lodgepole, 3 in young lodgepole 2 8- forests, 3 in spruce-fir forests (Picea 3 6 - spp. and Abies lasiocarpa), and 2 in 0 Douglas fir (Pseudotsuga menziesii) 4 E 2 Bench Creek Lamm Noutain- RAO» Ridge Varied stands (Figure 5). 044 heterogeneous 0 Topography The dead large mammals were all None 1-6 7-11 - 12-24 25.45 found in sites where sustained wind Degree of slope Figure 3. Percentage of elk carcasses killed speeds of 10-20 kilometers per hour by the 1988 fires in various topographic (kph) with gusts to 60 kph were doc- Figure 5. Slopes where fire-killed elk car- sites. umented during the fires and where casses were located during 1988.

November 1989 719 (28) black bear activity at 7%, and eagle sions that did not burn, and sedges 100 (33) that became green again after the fires 9° (146) activity at 7%. More than one species t 80 of scavenger used many of the car- from sites that did burn. But as snows_ 70 deepened, these limited forages be- 60 casses (Figure 7). a 50 came much less accessible. 40 Proportionally fewer mature bull 30 (60) Elk distributions 20 elk than cows left the mostly burned, (23) 10 (99) Elk numbers and winter distributions or partially burned, study areas im- S D. 0 9); Sept. 16 Sept. 23 Oet 30 Nov. Dee. have been assessed each year since mediately after the fires (Figure Date, 1988 1985 by two or three aerial surveys of the unburned study area is located in the entire northern winter range. the upper portions of the winter range Figure 6. Consumption of fire-killed elk Monthly monitoring was conducted where snow is deepest. Because they carcasses by scavengers during 1988. during the winter of 1988-1989 on remained in greater numbers in these three watershed study areas: un- areas, bulls died at higher rates than burned (Rose Creek), approximately cows; by late winter, bull ratios in the 100 northern herd were only 18 bulls per 90 half burned in a mosaic pattern (Am- 80 ethyst Creek), and mostly burned 100 cows compared to a typical ratio (Blacktail Deer Creek). A sightability of 30 per 100 (1986-1988; Figure 9° so correction factor was based on sight- 10). ; 40 ings of 34 radiocollared elk (Samuel McCullough (1969) argued that et al. 1987). A step-wise logistic re- bull elk are subjected to a higher 3°20 10 gression analysis equation was used mortality rate than cows due to en- 0 to evaluate the effect of the following ergy depletion and injuries associated 0 1 2 3 4 Number of scavenger species using carcass factors on observability of elk groups: with the rut and also due to greater percent tree cover, group size, and movement rates. Our observation Figure 7. Number of scavenger species observer. 9 that older bulls are less likely to mi- known to use fire-killed elk on the basis of Elk moved to winter ranges four to grate from burned winter ranges is signs at the carcasses. six weeks early in 1988, apparently in contrary to this argument and the response to both the drought and the proposals of Mitchell et al. (1977), fires. Elk also migrated from the park who along with Geist (1982) hypoth- 2000 esized that bull elk are less loyal to 1750 in larger numbers than in recent 1500 -•-- Burned years. An estimated 54% of the established home ranges than were - Partially burned 1250 •ito northern herd migrated across park cows. Flook (1970) observed bulls to —0-- Unburned O 1000 boundaries, where approximately colonize new habitat before cows did, 750 18% of the winter range exists but suggesting that bulls are less loyal. 500 -6. Calf elk are also more vulnerable to 250 where no fires burned. This large mi- 0----o 0 gration was probably related to the winterkill than are cows (Figure 10). 86-87 87-88 t8ept. SO Nov. 88 Jan. 89 Feb- 89 April 89 Dates drought effects on forage abundance, By late winter, only 7 calves per 100 tr. the burning of winter ranges, and a cows were left alive, compared to a heavy snowpack. The winter of typical late winter ratio of 20 calves Figure 8. Numbers of elk observed in 1988-1989 was only the third time per 100 cows. burned, partially burned, and unburned since 1916 that more than one-half study areas on Yellowstones northern the herd migrated from the park Winterkill in 1988-1989 range after the fires of 1988. (Houston 1982). One of these winters, 1919-1920, also followed a Carcasses of winterkilled elk were summer of severe drought. counted using a helicopter on a set of 60- In November 1988, normal num- random sites comprising one-third of 50- bers of elk occupied the unburned and C partially burned study areas, but only 50 8 40- Calves Bulls 8 45% as many occupied the burned 40 7 30- study area (Figure 8). Proportionately i 20- more animals left the burned and par- m 10_ tially burned study areas as the winter 0 progressed. Even in burned areas, elk 1987-88 Sept 88 Nov. 88 Dec. 88 Apil 89 in early winter were able to find alter- Dates +. nate forages such as the bark from 0 Early Late Early Late Winters Early Late LL sn. downed, burned, but still-green aspen wInter winter winter winter 85-87 winter winter 85-87 8947 88-89 88-89 88-89 8849 trees (Populus tremuloides), unburned Dates Figure 9. Ratios of bull to cow elk on grasses and sedges from mesic depres- burned, partially burned, and unburned Figure 10. Calves and bulls per 100 cows study areas during the winter after the 9F. J. Singer and E. 0. Garton, 1989, unpub- in Yellowstones northern elk herd after fires of 1988. lished data. the fires of 1988.

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Table 2. Ungulate population responses to the fires of 1988 and the 1988-1989 winter, Yellowstone National Park, WY. Percent of winter range burned Spring Estimated Dry Wet All Early Corrected 1989 Corrected % Herd Known Carcasses number of Ungulate population grassland meadow Forest types count estimate count estimate reduction harvest counted carcasses Elk Upper Yellowstone- Thorofare 0 55 26 50 461 57 Migrated Madison-Firehole 15 27 38 41 — 199 tr 330 469-66- 7 Northern 8 1 11 34 10,908 17,207- 8739 11,801- 38-43 2773 1004 3021- 19,059t 13,137t 5757#

Mule deer 0 0 0 0 2217 1796 19 — Pronghorn 0 0 0 0 4735 372 27 49 — Estimate based on a helicopter count and correction factor for half of the winter range; 264 dead elk were directly counted in the other half of the winter range by ground crews of the Interagency Grizzly Bear Study Team. tSightability estimates following Samuel et al. (1987). Estimate based on a helicopter count of one-third of the area (in 22 count units randomly selected from 66). The helicopter count was corrected by a simple ratio estimator (5.46 ± 1.7) calculated by comparing helicopter to ground counts (representing nearly total counts) on 13 small study plots of 3-12 km2. 5D. Scott, 1989, unpublished data. Yellowstone National Park, WY. the entire northern range. A correction burned and their population changes Increased body size and improved factor for the efficiency of the helicop- during the winter of 1988-1989 more condition of adults and increased calf ter surveys was established through in- directly reflect a response to the drought survival are predicted for 1990. Al- tensive ground survey of 13 sample and the winter conditions. Mule deer though the positive effects of the fires plots of 5-14 km2. Similar ground and counts declined 19%, and pronghorn on grasses and herbs may be short- helicopter surveys were conducted in counts declined 29% (Table 2). lived (Hobbs and Spowart 1984, the Madison-Firehole winter range. Wood 1988), lasting perhaps only A group of elk from the North Fork Projections two to three years, the structural and Shoshone herd, which typically win- successional changes to lodgepole for- ters in what was the most severely The elk remaining likely lost signifi- ests on the parks higher plateaus are burned winter range in the upper Yel- cant amounts of body weight, which expected to create additional elk sum- lowstone-Thorofare area, apparently could not be recovered by the time of mer range for as many as 30 years. migrated to the east. An early winter calving. Therefore, we predicted calf These changes are expected to include count conducted in the burned winter weights and survival would be re- more sunlight reaching the forest range was 461, but only 57 elk were duced (Thorne et al. 1976). In 1989, floor, creation of small meadow counted in January 1989 (Table 2). we found that calf weights were re- openings, a greatly increased herba- Elk winterkill in the Madison-Fire- duced 1.7 kg (17%), and the initial ceous and shrub layer, and higher hole winter range, where fire had (first six weeks) calf mortality rate palatability of forages. Elk diets will affected 41% of the area, was ap- was twice that of previous years.10 likely be more diverse due to the proximately 50%. The northern Yel- Herbaceous and shrub production projected increases in deciduous lowstone elk herd declined 38-43% will likely increase in the burned areas browse available to elk. Summer during the winter of 1988-1989, of (Lyon and Stickney et al. 1976). Protein home ranges of elk and movements in which 14-16% were harvested by hu- content and palatability also will likely burned or mosaic-burned areas are mans and another 24-27% were increase in the forages returning on likely to be smaller than before burn- killed by natural forces. During the burned areas (Spalinger 1986). Most ing, as a result of the increased plant mild winters of 1986-1987 and 1987- forages will recover almost immedi- productivity. We predict that the size 1988, elk mortality was less than 5%. ately, because root sources are still alive of the parks elk herds will likely Houston (1982) reported that in the in most cases beneath 2.5 cm of soil. increase as a result of the 1988 fires, severe winter of 1974-1975, 10% of Elk in Yellowstone have been ob- depending on the severity of winter the northern herd died. He made no served to consume many forages in conditions during the next few years. correction for carcasses not seen and burned areas that were ignored before therefore may have underestimated burning, apparently due to increased the winterkill. Park staff reported that palatability. Leege (1968) and Keay Research opportunities 60% of the northern herd died in the and Peak (1980) have observed that The fires of 1988 have provided a severe winter of 1919-1920, which less palatable shrubs received in- unique opportunity to observe the followed the drought of 1919. Hous- creased use by elk and mule deer after responses of extensive populations of ton (1982) later questioned the accu- fires.11 large mammals to large-scale fire, in- racy of their estimates, but we believe cluding the ranges of several large a large winterkill occurred. herds, and to test several research and 10F. Singer and A. Harting, 1989, unpublished Mule deer and pronghorn antelope data. Yellowstone National Park, WY. management hypotheses. The fires di- were less affected by the fires of 1988, 11D. Despain, 1988, personal communication. rectly killed only 1% of the elk, but because none of their winter range Yellowstone National Park, WY. the combined effect of drought and

November 1989 721 fire was a large die-off during the osystem, from microbes to large mam- of prescribed fire on nutrition and mountain following winter. The hypothesis that mals. It is important to set up research sheep and mule deer during winter and spring. J. Wildl. Manage. 48: 551-560. the fires greatly enhanced the future programs immediately to follow long- Houston, D. B. 1973. Wildfires in northern range carrying capacity for the north- term aspects of the recovery process. Yellowstone National Park. Ecology 54: ern herd may now be tested. Aspen 1111-1117. and willow communities have existed . 1976. The status of research on ungu- Acknowledgments lates in northern Yellowstone Park. Pages largely in the absence of fires since the 11-27 in Research in the Parks. Transac- mid-1800s (Houston 1973). We can We are grateful to Chief Ranger Dan tions of the National Parks Centennial Sym- now see what effect fire has on the Sholly, Chief of Research John Varley, posium, American Association for the Ad- vigor and heights of sprouts and to and many other members of the Yellow- vancement of Science. US Department of the see if fire-stimulated sprouts escape stone National Park staff for aircraft Interior, National Park Service Series No. 1. 1982. The Northern Yellowstone Elk: the height of elk browsing. and administrative support. Steven P. Ecology and Management. Macmillan, New Houston (1982) has hypothesized French of the Yellowstone Grizzly York. that precipitation influences grassland Foundation analyzed the trachea sam- Howard, W. E., R. L. Fenner, and H. E. Childs dynamics on the northern range more ples from elk. Gerald R. Green, Dave Jr. 1959. Wildlife survival in brush burns. J. Range Manage. 12: 230-234. than do elk numbers. Grassland data Mattson, and Jeff Henry of the Inter- Komarek, E. V. Sr. 1969. Fire and animal from 1989 can provide a test of this agency Grizzly Bear Study Team pro- behavior. Proc. Tall Timbers Fire Ecol. hypothesis, because wet conditions vided ground tallies of winterkilled elk. Conf. 9: 160-207. (24% above normal precipitation James Reardon, Yellowstone National Leege, T. A. 1968. Prescribed burning for elk in January-June) followed severe Park, assisted in the analysis of the data. northern Idaho. Proc. Tall Timbers Fire Ecol. Conf. 8: 235-254. drought and the intense grazing pres- Lieb, J. W., and C. L. Marcum. 1979. Biotele- sure that peak elk numbers exerted on References cited metric monitoring of heart rate and activity the ranges in winter 1988-1989. in elk. Pages 21-32 in F. M. Long, ed. Pro- The fires of 1988 also have pro- Baker, D. L., and N. T. Hobbs. 1982. Compo- ceedings of the Second International Confer- sition and quality of elk summer diets in ence on Wildlife Telemetry. University of vided the opportunity to observe the Colorado. J. Wildl. Manage. 46: 694-703. Wyoming, Laramie. effects of fall burning on forage abun- Beetle, A. A. 1974. The zootic disclimax con- Lyon, L. J., and P. F. Stickney. 1976. Early dance, forage quality, and nutrient cept. J. Range Manage. 27: 30-32. vegetal succession following large northern flows on a large ecosystem scale. The Bendel!, J. F. 1974. Effects of fire on birds and Rocky Mountain wildfires. Proc. Tall Tim- fires may enhance the spatial and mammals. Pages 73-138 in T. T. Kozlowski bers Fire Ecol. Conf. 16: 355-375. landscape relationships of water, and C. E. Ahlgren, eds. Fire and Ecosystems. McCullough, D. R. 1969. The Tule elk: its Academic Press, New York. history, behavior and ecology. Univ. Calif. cover, and forage areas. An alterna- Blanchard, B. M., and R. R. Knight. In press. Publ. Zool. 88: 1-209. tive hypothesis is that the quality and Reactions of Yellowstone grizzly bears to Mitchell, B. B., W. Staines, and D. Welch. quantity of summer range was not wildfire. Nature. 1977. Ecology of Red Deer: A Research limiting before the fires and the effects Buckley, J. L. 1958. Effects of fire on Alaskan Review Relevant to Their Management in wildlife. Pages 123-126 in A. B. Meyer, ed. Scotland. Institute of Terrestrial Ecology, of the fires will be relatively minor. Proceedings of the Meeting of the Society of Banchory, Scotland. Elk selectively forage for high- American Foresters. Society of American Moylan, J. A. 1980. Smoke inhalation and quality diets even in variable environ- Foresters, Washington, DC. burn injury. Surg. Clin. North Am. 60: ments (Baker and Hobbs 1982). For Cahalane, V. H. 1941. Wildlife surpluses in the 1533-1540. example, Rowland et al. (1983) found National Parks. Trans. N. Am. Wildl. Nat. Rowland, M. M., A. W. Allredge, J. E. Ellis, Resour. Conf. 6: 355-361. B. J. Weber, and G. C. White. 1983. Com- no difference in quality of winter diets Canon, S. K., P. J. Urness, and N. V. DeByle. parative winter diets of elk in New Mexico. of elk between burned and unburned 1987. Habitat selection, foraging behavior, J. Wildl. Manage. 47: 924-932. Ponderosa pine (Pinus ponderosa)- and dietary nutrition of elk in burned aspen Samuel, M. D., E. 0. Garten, M. W. Schlegel, bunchgrass types in New Mexico, and forest. J. Range Manage. 40: 433-438. and R. G. Carson. 1987. Visibility bias dur- Canon et al. (1987) also found no diet Chase, A. 1986. Playing God in Yellowstone: ing aerial surveys of elk in north-central The Destruction of Americas First National Idaho. J. Wildl. Manage. 51: 622-630. quality or species composition differ- Park. Atlantic Monthly Press, Boston. Skinner, M. P. 1928. The elk situation. J. ence in elk diets between burned and Chew, R. W., B. B. Butterworth, and R. Grech- Mammal. 9: 309-317. unburned aspen types in Wyoming. mann. 1958. The effect of fire on small Spalinger, D. E., C. T. Robbins, and T. A. Han- Canon and his colleagues, however, mammal population of chaparral. J. Mam- ley. 1986. The assessment of handling time in did conclude that elk forage efficiency mal. 40: 253. ruminants: the effect of plant chemical and Cole, G. F. 1971. An ecological rationale for physical structure on the rate of breakdown was greater in the burned areas as the natural or artificial regulation of native of plant particles in the rumen of mule deer measured by bites per minute, average ungulates in parks. Trans. N. Am. Wildl. and elk. Can. J. Zool. 64: 312-321. bite size, and travel time while forag- Nat. Resour. Conf. 36: 417-425. Thorne, E. T., R. E. Dean, and W. G. Hep- ing. The fires of 1988 will also pro- Despain, D., D. Houston, M. Meagher, and P. worth. 1976. Nutrition during gestation in vide the opportunity to see if Yellow- Schullery. 1986. Wildlife in Transition: Man relation to successful reproduction in elk. J. and Nature on Yellowstones Northern Wildl. Manage. 40: 330-335. stones largely unhunted northern elk Range. Roberts Rinehart, Boulder, CO. Walker, H. L., C. G. McLeod, and W. L. Mc- herd will naturally regulate its num- Flook, D. R. 1970. A study of sex differential in Manus. 1981. Experimental inhalation in- bers if there is, as hypothesized, rapid the survival of wapiti. Can. Wildl. Serv. Rep. jury in the goat. J. Trauma. 21: 962-964. population growth after the fires. Ser. 11. Weaver, J. 1978. The wolves of Yellowstone. The Yellowstone fires offer unique Geist, V. 1982. Adaptive behavioral strategies. National Park Service Natural Resources Re- Pages 219-277 in Elk of North America: port No. 14, Washington, DC. opportunities to address important re- Ecology and Management. Stackpole Books, Wood, G. W. 1988. Effects of prescribed fire search questions. We can observe the Harrisburg, PA. on deer forage and nutrients. Wild!. Soc. consequences of fire throughout the ec- Hobbs, N. T., and R. A. Spowart. 1984. Effects Bull. 16: 180-186.

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