Yellowstone ScienceA quarterly publication devoted to the natural and cultural resources

Volume 4 Number 4

A Century of Managing FishExotics and EcosystemsInsect Vampires

Being autumn, change is in the air:change in the color of the aspen, cotton-wood, and alder leaves (yes, even here inYellowstone)as they float to theground...change in the waters of Yellow-stone Lake, where the lake trout come tothe shallows to spawn as the autumnwinds buffet the gillnetters seeking themout...change in the movements of thebighorn, elk, and bison as they movefrom summer ranges toward the winterranges before, during, and after theirmating seasons...each movement its ownkind of migration, be it from the tree tothe ground, the depths to the shallows,high elevation to low. Some of thesemigrations are natural to Yellowstone,

and some newly arrived, with or withoutthe assistance or planned forethought ofhumans. Change, it is said, is the only realconstant, and documenting it dominatesour research and management efforts. Inan interview with Yellowstone Science,distinguished conservation biologistMichael Soulé cautions against compla-cency in the face of exotic invasions andpreviously unexperienced rates of spe-cies’ extinctions and invasions on broadgeographic scales. On a more local scale,John Burger tells us in sometimes painfuldetail about the invasions of both exoticand native “bloodsuckers” ontoYellowstone’s wildlife—and under ourown sensitive skins. And Mary Ann

Franke documents the history of fisheriesmanagement in Yellowstone as the U.S.Fish and Wildlife Service departs thepark, leaving a legacy that spans the spec-trum—from the heyday of fish rearingand planting to full-bore efforts to eradi-cate exotics and restore natives. Our part-ners in fisheries management leave us asolid, long-term database on aquatic re-sources that’s the envy of many biolo-gists, and with many fond memories ofprofessional work, cheerfully done onbehalf of Yellowstone National Park.Their migration elsewhere leaves me sad-dened, and I wish them well.

SCM

Complacency and Change

A quarterly publication devoted to the natural and cultural resources

Yellowstone Science is published quarterly, and submissions are welcome from all investigatorsconducting formal research in the Yellowstone area. Editorial correspondence should be sent tothe Editor, Yellowstone Science, Yellowstone Center for Resources, P.O. Box 168, Yellowstone

National Park, WY 82190.

The opinions expressed in Yellowstone Science are the authors' and may not reflect eitherNational Park Service policy or the views of the Yellowstone Center for Resources.

Copyright © 1996, the Yellowstone Association for Natural Science, History & Education.

Support for Yellowstone Science is provided by the Yellowstone Association for NaturalScience, History & Education, a non-profit educational organization dedicated to serving the

park and its visitors. For more information about the Yellowstone Association, includingmembership, write to P.O. Box 117, Yellowstone National Park, WY 82190.

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13Editor

Sue Consolo-MurphyArt Director

Renée EvanoffAssociate Editor

Sarah Broadbent Assistant Editor

Mary Ann FrankeInterview Editor

Paul SchulleryPrinting

Artcraft Inc.Bozeman, Montana

On the cover: Ranger John Jaypacking fish to a remote lake inYellowstone in the summer of1938. Above: the park service“fish truck” used for stockingfish in more accessible locations.Photo taken in 1935. See therelated story on page 2. PhotosNPS archives.

A Grand ExperimentThe first half-century of fisheries research and management is filledwith a high degree of manipulation, as fish were hatched, stocked,and caught in dozens of park waters, all in attempts to “improveupon nature” and provide recreation to the masses.Part One of an article by Mary Ann Franke

Natives Versus ExoticsEcosystems, while never static, are experiencing rates of changethat alarm many ecologists. A distinguished conservation biologistshares his views on how Yellowstone is threatened by an influx ofexotic plants and animals.Interview with Michael Soulé

Yellowstone's Insect VampiresMore than you ever hoped to know about the many minisculethings that bite you and other animals for their own survival.by John Burger

News and NotesPresident announces settlement on New World Mine • Wolfpopulation continues to grow • Record fire season comparativelyquiet in Yellowstone • Fourth Biennial Science Conference to beheld in Yellowstone • Record year for grizzly bear cubs • Visitingscholar Todd Fuller works with wolf project

Table of ContentsVolume 4 Number 4 Fall 1996

Yellowstone Science

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Yellowstone Science

Park rangers planting fish in a Yellowstone lake, 1922.

Photos courtesy NPS Archives

A Grand Experiment100 Years of Fisheries Management in Yellowstone: Part I

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October 1996 marks another milestonein management of Yellowstone’s fisher-ies, as the U.S. Fish and Wildlife ServiceFisheries Assistance Office departs thepark after 35 years. The NPS, alreadyresponsible for fisheries managementpolicy-setting and enforcement, must pro-vide its own resident fisheries expertiseas it does for other natural and culturalresources. To mark this passage, and tosummarize for readers the long and com-plex history of Yellowstone’s fisheries,we present the first of a two-part featureby Mary Ann Franke. Part I covers theperiod from the park’s inception to the1950s; Part II, covering the changingtimes from the 1950s to the present, willbe featured in the January 1997 issue ofYellowstone Science. Franke is a free-lance writer who spent the summer of1996 researching this and other subjectsin Yellowstone. Her piscatory pursuitshave also led her to drop lines in Olympicand Virgin Islands national parks.

In prehistoric campsites by the Yel-lowstone River, notched stones have beenfound that are believed to have been usedto weight nets for catching cutthroat trout.If this was among the first human alter-ations of the Yellowstone landscape inpursuit of fish, it was but a tiny harbingerof the changes to come.

Only 17 of the more than 150 lakes inYellowtone National Park are believed tohave contained fish when the park wasestablished. About 40 percent of all thepark’s waters were fishless, including

almost the entire lengths of the Firehole,Gardner, Gibbon, Lewis, and Bechlerrivers. Yet the physical character ofYellowstone’s waters was found to begenerally favorable for fish habitat. Afield study in 1890 revealed the presenceof abundant insect and crustacean foodwell-suited for sustaining fish.

Where Geologic and Human HistoryCollide

Yellowstone’s relative scarcity of na-

“It would be an admirable thing if trout and grayling could be planted in thesebarren waters, but Commissioner McDonald looks at this subject from a broaderstandpoint, and sees the grand opportunity which the Park offers for experimentson the acclimatization of certain species of fish foreign to these waters. He hasexpressed himself as desirous of introducing into one of these river systems thebrown trout of Europe; the Eastern brook trout might be introduced in another,and the grayling in the third.”— Forest and Stream: A Weekly Journal of Rod andReel, 1889.

by Mary Ann Franke

Fall 1996

tive fish is a result of its geologic history.After the last period of glaciation some12,000-15,000 years ago, fish began toreestablish in those waters to which theirpassage was not blocked by waterfallsand cataracts. When the park was estab-lished in 1872, few fish lived above thefalls except in Yellowstone Lake andRiver. The cutthroat trout there are be-lieved to have used Altantic and Pacificcreeks on Two Ocean Plateau to cross theContinental Divide.

Yellowstone’s current abundance ofnon-native fish is a result of its morerecent history. Various combinations ofnative and exotic fish species now inhabitabout 40 of the park’s lakes and most ofits rivers and streams. By 1902 four non-native trout species (brook, brown, lake,and rainbow) that wouldw compete with12 species of native fish had already beenbrought in, and for decades afterwardsuch planting seemed a perfectly naturalhuman response to so-called “barren” orotherwise inadequately fish-stocked wa-ter. From a modern ecological perspec-tive it was as if, thinking the HaydenValley looked rather empty, park manag-ers had decided to bring in livestock, orrhinoceri.

How and why the park’s particular fishmenagerie came about, and what is beingdone about it now, is a story writ large ofwilderness management during the lasthundred years, with all of its blunders andrevelations. The chapters include subsis-tence use and commercial sale, import ofnew species and loss of original ones,catering to recreational interests, learn-ing ecological principles, regulation ofhumans to permit greater “natural” regu-lation, and attempts to restore native spe-cies.

The Experiment Begins

When the Yellowstone Park Act of1872 specified that the land be “set apartas a public park or pleasuring ground forthe benefit and enjoyment of the people,”the idea of a national park as a sanctuaryfor wildlife was still in the future. Hunt-ing and fishing were regarded as legiti-mate recreational activities and the onlypractical way to feed park visitors. Butthe decimation caused by commercialharvest of fish and game was so extensive

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Loch Levan troutfrom Scotland( o r i g i n a l l ytransplanted toYellowstone in1890) displayedby two MammothHotel bellhops in1930.

that by 1883 fishing was limited to hookand line and hunting was prohibited ex-cept for predators. In 1886 the U.S. Cal-vary was assigned to the park and eventu-ally proved to be adept at protecting thepark’s resources.

Early on, stocking park waters to im-prove angling opportunities seemed aworthy goal. In his Superintendent’s Re-port for 1889, Captain Frazier Boutelleenthused: “Besides the beautifulShoshone and other smaller lakes, thereare hundreds of miles of as fine streams asany in existence without a fish of anykind. I have written Col. MarshallMcDonald, U.S. Fish Commission, uponthe subject, and have received letters fromhim manifesting a great interest. I hopethrough him to see all of these waters sostocked that the pleasure-seeker in thePark can enjoy fine fishing within a fewrods of any hotel or camp.”

Colonel McDonald’s great interest inthis proposal arose from his fledglingorganization’s need for an outdoor labo-ratory in which to apply its new science.Yellowstone’s waters represented an op-portunity to broaden the FishCommission’s activities from concernabout the price of shad to the develop-ment of a sport fishery in what was thenthe only wildland under active federalmanagement. The Fish Commissionasked eminent scientist David Starr Jor-dan to catalogue the park’s fish, describetheir habitat, list the “barren” waters, andadvise as to which were suitable for stock-ing. Jordan’s report provided detailsabout Yellowstone’s native fish decadesbefore much was known about other parkwildlife.

Following Captain Boutelle’s recom-mendation, in 1889 the Fish Commissionbrought 7,000 yearling brook, brown,and rainbow trout from a Michigan hatch-ery to plant in the fishless upper waters ofthe Firehole, Gibbon, and Gardner rivers.The east fork of the Gardner above OspreyFalls also received 1,000 cutthroat troutfrom the Snake River in Idaho. In 1890,when fewer than 8,000 people entered thepark, more than 42,000 yearlings, includ-ing Loch Levan brown trout from Scot-land and Von Behr brown trout fromGermany, went into Lewis and Shoshonelakes, which had been fishless for per-haps 9,000 years. Mountain whitefishfrom Montana went into Twin Lakes andthe Yellowstone River below Yellow-stone Lake, to provide “food for the na-tive trout, which appear to be underfed,”as urged byForest and Stream in 1889.“If enough of these whitefish escape theirenemies to spawn, we are inclined to lookfor a marked alteration in the character ofthe trout of the Yellowstone Lake.” Thiswas but one of many fish lessons thatwould be learned by trial and error: themountain whitefish showed no aptitudefor life in the upper Yellowstone and thecutthroat of Yellowstone Lake haveshown little interest in eating other fish.

But at the time, all things still seemedpossible when it came to man bendingnature to his will. At the end of 1890,Captain Boutelle reported that ColonelMcDonald “has now hatched and readyfor shipment, as soon as I telegraph himthat the mountains are passable, 150,000trout and salmon for the lakes and riversof the Park. It will probably be the great-est feat in moving large bodies of young

Yellowstone Science

Native Species

None

Longnose daceMottled sculpinArctic graylingCutthroatMountain Whitefish

Yellowstone cutthroatLongnose daceLongnose suckerMountain sucker

Yellowstone cutthroatLongnose daceMountain suckerMountain whitefishArctic Grayling

None

Yellowstone cutthroatLongnose daceLongnose sucker

Yellowstone cutthroatLongnose dace

Yellowstone cutthroatLongnose daceLongnose suckerMottled sculpinMountain suckerMountain whitefish

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Fish Past and Present: A Sample of Yellowstone Waters

Extant

Extinct or not viable

Park Location

Firehole River aboveFirehole Falls

Gibbon River

Lamar River andSoda Butte Creek

Madison River

Shoshone Lake

Slough Creek

Yellowstone Lake

Yellowstone Riverbelow Lower Falls

Introduced Species

Brook troutBrown troutRainbow troutYellowstone cutthroat

Brook troutBrown troutBlack bassRainbow trout

Rainbow trout

Brook troutBrown troutRainbow trout

Brook troutBrown troutLake troutRedside shinerUtah chub

Lake chubRainbow trout

Atlantic salmonMountain whitefishRainbow troutLake chubLake troutLongnose suckerRedside shiner

Brown troutBrook troutRainbow trout

fish ever attempted and will reflect aworld of credit upon Colonel McDonald...The streams are full of fishfood and therecan be no reasonable doubt of the successof the enterprise. Once stocked and pro-tected, it will be impossible in the shortseason the Park is accessible to fish themout.” Although Captain Boutelle’s ambi-tious goal for 1891 was not met, he hadset wheels in motion that would not grindto a halt until more than 60 years later,after 310 million fish had been planted inYellowstone waters and the possibility offishing out the native species had beensquarely faced.

“Improving on Nature”

Park personnel preparing to poisonperch in Goose Lake, 1938.

“Within a few years after experi-enced fish-culturists began to giveattention to needs of the park, thehitherto fishless waters began toproduce desirable game fish inabundance, and this has continuedup to the present time.”— HughSmith and William Kendall, TheFishes of Yellowstone, 1921.

“I believe that it would be better to haveYellowstone Lake stocked with land-locked salmon, which would in time eradi-cate the wormy trout,” SuperintendentYoung advised the Fish Commissioner in1908, referring to the native cutthroattrout, which is often infected by a para-sitic tapeworm that is harmless to humanswhen the fish has been cooked.

Fortunately, the Atlantic salmon, rain-bow trout, and mountain whitefish plantedin Yellowstone Lake failed to survive, asdid the black bass that were reportedly putin the Gibbon River and several lakes inthe Lower Geyser Basin in 1895. Yellow

Fall 1996 5

fish was initially introduced through anofficial stocking program, their increaseddistribution within the park was some-times unsanctioned, and some waterstherefore have fish of uncertain origin.The non-native lake chub may have ar-rived through either the authorized stock-ing of minnows or the dumping of bait byanglers. Outfitters and anglers took itupon themselves to stock for their ownuse some of the park’s smaller, little-known ponds—and apparently, in thecase of the lake trout, one large and verywell-known body of water.

Authorized or not, enough stockingheld to recast the fish populations in manywaters. The Gallatin and Madison rivers,where the upper Missouri form ofwestslope cutthroat once resided with theArctic grayling and the mountain white-fish, today contain almost exclusivelywhitefish and non-native brook, brown,and rainbow trout. The Snake River fine-spotted subspecies of cutthroat trout ap-pears to have vanished from the park, andthe westslope cutthroat remains in only ahybridized form, because Yellowstonecutthroat were planted in its native wa-ters. Although the Yellowstone cutthroathad its range within the park expanded, itis gone from most native areas wherebrook trout were introduced, and in somewaters it hybridized with introduced rain-bow trout. Distribution of the Arctic gray-ling, once abundant in the larger streamsof the Missouri River drainage aboveGreat Falls, Montana, has been reducedto less than 8 percent of its original range.Although grayling are occasionally still

“Trout have been planted in nearlyall streams in the park except thosethat are tributary to YellowstoneRiver, and the experiment has beenso successful that there are now butfew places in this country where bet-ter sport can be had by the fisher-man... In order that it may never benecessary to make any restrictions itis strongly urged that a small fishhatchery be established here. If thiscan be done the streams can be keptso full of trout that it will be impos-sible for the tourists to deplete them.”— Captain John Pitcher, ActingSuperintendent, 1901

perch were later found there, in Featherand Goose lakes, and it may be that theyhad been mistaken for black bass, or thatthe plant was contaminated with perch. Inany event, the perch survived in GooseLake until 1938, when they were poi-soned to keep them out of the FireholeRiver.

But many plantings of non-native fishthrived because of the lack of competi-tion from other species. The FishCommission’s intention had been to keepspecies separate by putting them in dif-ferent drainages: this failed due to theease with which fish passed downstreamover waterfalls that prevented fish fromgoing up. As a consequence, species werecombined that were either incompatiblein some way, competing with each otherfor food or spawning areas, or too com-patible in another— interbreeding to pro-duce hybrids or otherwise diluting thegenetic makeup of a native species.

The first decades of the twentieth cen-tury brought to Yellowstone both the firstprivate cars—helping push annual visita-tion from 20,000 in 1914 to 260,000 in1929—and the improved means by whichits waters could be kept stocked for thegrowing number of anglers. The methodsof transporting fish by pack stock wererefined, and the practice of planting eyedeggs instead of the more cumbersomefingerlings came into vogue. Conse-quently, many fishless headwaters andbackcountry lakes acquired fish, and someheavily fished waters began to receivealmost annual plantings.

Although each new species of game

One of the first fish hatcheries at Lake, 1928.

found in the Gibbon and Madison rivers,no viable populations exist in any parkwaters in which the species was native.Grayling are plentiful in three once-fishless lakes where they were introduced,but these lacustrine (lake-dwelling) popu-lations do not play the same role in theecosystem as their fluvial (river-dwell-ing) relatives.

As for Yellowstone Lake, “it is inter-esting to note that native or cutthroat troutare the only specie found anywhere in thelake,” the Salt Lake Tribune observed in1928 with more wishful thinking thanaccuracy. “It is considered the greatestnatural reservoir in the United States forcultivation of that specie and the govern-ment has no intention of spoiling it byimporting other varieties.” But by thattime Yellowstone Lake had already seenthe arrival of the longnose sucker (inabout 1923), and it would eventually alsoaccommodate the redside shiner (firstreported in 1957), the lake chub (firstreported in 1958), and the lake trout (of-ficially confirmed in 1994). The lakechub populations are believed to be in-consequential and, despite some overlapin diet, neither the longnose sucker orredside shiner appear to compete directlywith the cutthroat. Spatial separationwithin the lake and both temporal andspatial separation in spawning streamshave apparently led to a stable associa-tion of these fishes, with both the redsideshiner and the longnose sucker havingfilled previously vacant niches within theYellowstone Lake ecosystem.

But the lake trout will be a different

Yellowstone Science6

story. Cutthroat trout will have to com-pete with juvenile lake trout for the sameinvertebrate food sources, while adultlake trout eat cutthroat trout themselves.In no body of water do lake trout coexistnaturally with cutthroat trout, and theyhave reduced or eliminated native troutspecies in places such as Heart Lake inYellowstone and Jackson Lake in GrandTeton National Park. It has been esti-mated that they could reduce Yellow-stone Lake’s cutthroat population by atleast 50 percent during the next 20 years.And because they spend most of the yearin deep water, lake trout will not replacecutthroat trout for many of the 42 speciesof birds and mammals that feed on them,including bald eagles, white pelicans,ospreys, loons, otters, and bears. For moreinformation, see “Yellowstone Lake inChange,” Yellowstone Science 4(2):4-9.

While an increasing number of fishwere being disbursed throughout Yel-lowstone waters, even more fish wereleaving, not only on anglers’ hooks, butas eggs and fry. The rest of the UnitedStates was experiencing the same stock-ing fervor that filled Yellowstone’s wa-ters. Between 1903 and 1953, 818 mil-lion trout eggs were exported fromYellowtone, where they were strippedfrom cutthroat spawners and incubated inhatcheries to improve their survival be-fore shipment.

Eggs of the cutthroat or “black-spot-ted” trout, as it was then called, were firsttaken in 1901 from streams in the WestThumb and sent to a South Dakota hatch-ery, but the park soon built its own opera-

tion with four hatchery buildings and fishtraps on 14 of Yellowstone Lake’s largesttributaries. “Without hatching facilities,it has been necessary to ship out the eggsin a green state and ship back the young,causing rather heavy mortality and con-siderable extra expense,” explained theFisheries Service Bulletin in 1921, whena hatchery was constructed at Soda ButteCreek near Trout Lake. “It is expectedthat the new hatchery will serve a veryuseful purpose in keeping up the supplyof trout in one of the most interestingsections of the park.”

From Grebe Lake, a once fishless lakethat had been stocked with a Montanagrayling genotype, about 72 million eggswere collected from 1931 and 1956, andtoday most western grayling stocks canbe traced back there. Both Grebe Lakeand Trout Lake, the site of a rainbow trouthatchery, were closed to fishing until1944 because of their fish culture opera-tions. Today Trout Lake’s pure cutthroattrout are gone; it contains only cutthroatand rainbow trout hybrids.

Altogether, more than 50 federal, state,and private hatcheries received eggs fromYellowstone. The annual take increasedto about 20 million eggs in 1911 andpeaked at 43 million in 1940, making theYellowstone cutthroat the most com-monly introduced cutthroat trout in theworld. Only later did it become apparentthat the species is suited only to alpine orsubalpine lakes that have few or no com-peting fish. The Yellowstone cutthroathas survived in seven western states andtwo Canadian provinces in which it was

A park ranger harvesting early “blackspotted” spawners at PelicanCreek in May of 1936. Right: Taking eggs for transplantation, 1930.

planted, but in only 15 percent of itsoriginal range in the Yellowstone andSnake river drainages.

The streams in which cutthroat troutspawn are usually swollen at the time ofthe run. Some cutthroat go far upstreamfrom the lake and deposit their spawnduring high water in places that later maybecome exposed to the air, resulting inhigh mortality. Streams that are ragingtorrents in spring and early summer mayby July and August become almost dry,cut off from the lake and reduced todisconnected pools, where the young fishwill perish.

The purpose of the hatcheries was toincrease the eggs’ survival rate by col-lecting them before they encountered allthese perils. To do that, the upstreammigrating fish were trapped in weirs andheld until their eggs ripened; after theeggs had been taken, the fish were re-turned to the stream. The hatcheries andtraps were supervised by the Rocky Moun-tain District of the U.S. Bureau of Fisher-ies under the loose and sometimes con-tentious guidance of park administrators.Fish culturists were recruited from fed-eral and state hatcheries to assemble inthe park during spawning season; eachstate receiving eggs generally providedone man for 60 days. But the egg collec-tion process posed its own risks. Thetraps’ fishy smell attracted bears, forwhom the presence of barbed wire, elec-tric fences, and guard dogs posed littledeterrence, and constant vigilance of the

Fall 1996 7

traps was required until the eggs werepicked up by the transport crew.

Recreation vs. Preservation

In retrospect, one might ask where werethe advocates of wilderness preservationwhile all of this fish stocking and egghatching was going on? The prudence ofputting some limits on fishing was evi-dent almost from the beginning. A mini-mum size for keepers recommended byActing Superintendent Captain GeorgeAnderson was formally adopted in the“Instructions to Persons TravelingThrough Yellowtone National Park” of1897: “All fish less than six inches inlength should at once be returned to thewater with the least damage possible tothe fish. No fish should be caught inexcess of the number needed for food.”Glen Creek was temporarily closed toangling in 1896, and again in 1907 alongwith Sportsman Lake when evidence ofexcessive fish catches was found.

By the first decade of the twentiethcentury, some park managers were be-ginning to rethink the policy of indis-criminate fish stocking. The first recordeddefense of native fish occurred in 1907when a fisheries employee was repri-manded for trying to plant rainbow troutin Yellowstone Lake. In 1908, the parkrefused the proposal of the Fish Commis-sioner to stock smelt in Shoshone andYellowstone lakes, as it also resisted sug-gestions to introduce other wildlife, in-cluding reindeer, mountain goats, andvarious game birds. But park managersdid not yet realize the extent to whichintroduced species could be harmful tonative species, nor did they stop the spreadof nonnative fish already present in Yel-lowstone to additional park waters.

For most of their early history, nationalparks treated wildlife as an enticementfor visitors and felt little compunctionabout meddling with it to enhance visitorsatisfaction. From 1896 to 1908, bison,elk, and mountain sheep were put on DotIsland for the viewing pleasure of theYellowstone Boat Company’s passen-gers. The superintendent at Sequoia rec-ommended complete elimination of bearsfrom that park, and noisy woodpeckersnear hotels in Yosemite were shot if guestscomplained. Even after passage of the

National Park Service Act in 1916, whichcalled for the conservation of wild ani-mals “by such means as will leave themunimpaired for the enjoyment of futuregenerations,” predators that were not anobvious part of the enjoyment continuedto be killed. These unwanted predatorsincluded the pelicans which ate tons oftrout from Yellowstone Lake, competingwith people who also did so.

Fishing had become an important partof the national park experience, and mostof the concern was about the quality ofthe angling, not the quality of the re-source. The growing number of anglers,the large take of eggs, and the high creellimit (20 fish/day from 1908 to 1920)were having an impact. Nonetheless,Superintendent Albright optimisticallyreported in 1919 that, as a result of plantsmade in recent years, the trout in Yellow-stone Lake seemed to be returning to their“former abundance before the depreda-tions of the pelicans, gulls, etcetera hadmade inroads on the stock”—as if it werethose pesky birds that had been respon-sible for the decline.

By the 1920s, some wildlife ecologistswere alarmed by the damage that hadbeen done to national parks as a result ofmisinformation and misguided manage-ment. The Ecological Society of Americaand the American Association for theAdvancement of Science announced theiropposition to the introduction of any morenew plants or animals to national parks.But although Yellowstone fishing wasnot as good as it had been, it became morefamous as park visitation increased. Evenwith the reduction of the daily limit to 10fish in 1921, Yellowstone offered bettersport fishng than many places.

Limited understanding of fish ecology,pressure to maintain Yellowstone’s sportfishery, and bureaucratic stalemate com-bined to continue fish culture operations.While the National Park Service (NPS)was awakening to the need to preservenative fish species, the U.S. Fish andWildlife Service (descendant of the U.S.Fish Commission) continued to mass pro-duce trout. No written agreement existedbetween the two agencies until 1939,when a Memorandum of Understandingwas drawn up that described in generalterms the extent of fish culture operationsin the park. Although often mutually ben-

eficial, the relationship between the twofederal agencies was occasionallystrained, and on several occasions Yel-lowstone officials tried to force the fishculturists out altogether.

“The National Park Service wildlifepolicy is consistent with the generaltheme of national park administra-tion, i.e., that the areas will be main-tained unimpaired for the benefit offuture generations... In view of thefact that fishing is permitted in cer-tain national park waters, a modifi-cation of the general wildlife policyis necessary... In waters where na-tive and exotic species now exist,the native species shall be definitelyencouraged, unless exotic speciesare better suited to the environmentand have proven of higher value forfishing purposes than native spe-cies.”— General Policies of theNational Park Service GoverningFish Planting and Distribution,1941.

Concern about both Yellowstone’snative fish and the quality of its sportfishing did lead to the establishment of aformal NPS stocking policy in 1936 whichprohibited planting exotics in waterswhere only native fish resided. It alsosuggested that, “It might be advisable toleave barren waters as such,” but it didnot entirely ban stocking. At the time, anycurtailment of fish stocking was consid-ered a radical idea, as was the reduction inthe daily limit from 10 to 5 fish in 1949.Thus the new policy did not change the“put-grow-and-take” maintenance of fishin many roadside waters, nor did it end“put-and-take” stocking of immediatelycatchable size, hatchery-raised rainbowtrout to increase the likelihood that an-glers would leave the park satisfied. ❧

A typical days catch of the 1920s.

Yellowstone Science8

Yellowstone Science Interview: Michael Soulé

Natives Versus ExoticsComing to Terms With Non-native Species Invasions and Rates of Change

➟

➟

Michael Soulé was the founder andfirst president of the Society for Conser-vation Biology. He is a fellow of theAmerican Association for the Advance-ment of Science, serves on the NationalResearch Council, and is a founding mem-ber of the Wildlands Project. His re-search interests include morphologicaland genetic variation in natural popula-tions of animals, island biogeography,population viability, consequences ofhabitat fragmentation, and the analysisof policy conflicts. His field work hastaken him to Africa, Samoa, Australia,Yugoslavia, Mexico, and the West Indies.He recently retired as Chair and Profes-sor Emeritus of Environmental Studies atthe University of California, Santa Cruz.

Soulé has published on a wide range oftopics and is well known for his editedbooks, Conservation and Evolution, Con-servation Biology: The Science of Scar-city and Diversity, Viable Populationsfor Conservation, and Reinventing Na-ture: Responses to PostmodernDeconstruction. He has defined conser-vation biology as a crisis discipline, say-

ing that “its relation to biology, particu-larly to ecology, is analogous to that ofsurgery to physiology... In crisis disci-plines, one must act before knowing allthe facts; crisis disciplines are thus amixture of science and art, their pursuitrequires intuition as well as informa-tion.”

Yellowstone was delighted to have Dr.Soulé visit in September 1995, when hewas invited to speak at the symposium“Carnivores and Ecosystems” followingthe park’s third biennial science confer-ence. Paul Schullery and John Varleyconducted this interview at that time.

YS: One of the things that the NationalPark Service (NPS) wrestles with con-stantly in many of its areas is the problemof exotic species. Over the course of thepast three-quarters of a century, we havebuilt up a powerful institutional compul-sion to fight exotic invasions as hard aswe can. But when we take the long view,we have to wonder if we’re just tempo-rarily holding off the inevitable. We knowthat new species have been colonizingYellowstone for 10,000 years and wecan’t prevent that. That isn’t to say thatthe accelerated rate of invasion by exot-ics that humans have caused here is some-how “natural,” but it is to suggest thatinvasions are truly unpreventable. Whatwith the high cost of running parks andthe decreasing budgets, we are forced to

Renée Evanoff John Laundré

Fall 1996 9

wonder if we can afford this kind of work.MS: Lots of things are inevitable. Deathand corruption come to mind. So, yes,invasions are inevitable. The question is,how aggressive should we be in combat-ting them so they don’t become lethal.Like diseases, some invasions are moreserious than others.YS: Why has this become such an urgentproblem in recent times?MS: We’ve seen an extraordinary in-crease in the numbers of invasions overthe last century. It has to do with theincrease in human population and themodern technology of travel and trans-portation. For example, the first time Iwent to Europe I went on a boat. Nobodygoes to Europe by boat anymore. But ifyou cross the ocean by ship, you havetime to wash your clothes and get theseeds out of them. If you’re traveling byplane, however, you can bring insectsand seeds across the ocean or from Mexicoto Colorado.YS: You said that some invasions aremore serious than others. How does onego about judging such things?MS: You can’t. You never know whichspecies will become invasive. It’s gettingto the point where you need some kind ofa triage system in places like Yellow-stone. One approach is to develop a list ofall exotics in the park and decide whichyou can live with and which you can’t,and then spend your money on those thatare unacceptable.

What is a “Native” Species?

YS: The national parks have been deal-ing with that decision-making processfor a long time, and it has led us in someunusual directions. In the 1970s, therewas a movement to institutionalize therecognition that we couldn’t get rid ofsome exotics, especially sport fish thathad been introduced in a lot of parks backbefore we knew better. It was proposedthat we declare brown, rainbow, and east-ern brook trout “naturalized.”MS: Honorary natives.YS: Right. That was hotly debated for awhile, and the people who opposed itwon out at the time. There seemed no realneed to do it, and there seemed a risk ofgiving managers an easy way out of toughmanagement situations that shouldn’t be

susceptible to resolutionby surrender. Are youproposing anything likethat? Can we arbitrarilydecide what is native?MS: I wouldn’t go thatfar. Aquatic systems arethe most susceptible toinvasion, and they arealso the ecosystemswhere invaders are likelyto be the most popular; alot of people like rainbow trout, even ifthey cause the local extirpation of nativeamphibians. And of course a lot of sports-men don’t know or don’t care about thedifference. Nowadays, commerce is in-troducing a new set of aquatic invaders.Zebra mussels are a good example of thecomplexities of these invasions. Theyoriginated in warm seas like the Caspianand Yellow seas. But as the climatewarms, species that we thought couldn’tsurvive in colder regions might becomeinvasive. So climate warming and inva-sions are inseparable processes that areboth caused by humans, and are com-plexly interrelated.YS: One objection that we hear to all thisconcern over invasions is that they havealways happened; they’re just happeningfaster now, so what’s the big deal?MS: That is, indeed, a common re-sponse. I refer to it as the “Rush Limbaughresponse” because it overlooks some-thing very important—differences inrates. When rates undergo a large in-crease, we need to pay attention. Ex-amples include the increases in humandeath rates attributable to smoking anddrunk driving. As a society we can’tafford to dismiss these large increases inrates just because death is nothing new.

The Increasing Rate of Invasion

YS: Yes, it appears to reveal an extraor-dinary anthropocentrism to say “so what?”in the face of the ecological changes thatare now occurring. One doesn’t have tobe an alarmist to sense that something iswildly out of control.MS: I agree. Civilization is runningamok, and ecosystems are victims. Bythe way, another example of the “RushLimbaugh fallacy” is the claim that “ex-tinctions of species have always occurred,

so what is all the shouting about.” Again,those who make this claim want to glossover the huge increase in the rate ofextinction. The rate is thought to be ap-proaching 1000 times the normal back-ground rate in the world. And unless yourdefinition of “natural” is distorted, thisamazing rise in the rate of extinction isn’tnatural. I think that there have been, per-haps, one or two natural extinctions ofvertebrate species in the last several hun-dred years, but during the same periodthere have been hundreds of human-caused extinctions.

Returning to the subject of invasivespecies: as plants, animals, and diseasesare moved with increasing rapidity be-tween continents, mankind is reversingmore than 100 million years of continen-tal isolation. Some are calling this periodthe “Homogocene.” I prefer the“Catastrophozoic.” The practical prob-lem is that a lot of these alien species arequite aggressive, and are significantlydegrading the invaded ecosystems, theway that cheatgrass is changing the GreatBasin and affecting its productivity fornative species as well as for cattle.YS: Are these changes uniform across alandscape? Are some parts of a continentmore vulnerable than others?MS: Indeed, some kinds of ecosystemsappear to be more vulnerable than others,though we are still trying to understandthe reasons. In terrestrial ecosystems,those habitats that are subject to soil dis-turbance and that lack a canopy of treesappear to be the most easily invaded.High-elevation habitats appear to be lessvulnerable, possibly because of the se-verity of the climate and lower probabil-ity of aliens arriving from colder regionsof Eurasia and South America. The ex-ception, of course, is fresh water. Riversand lakes appear to be the most vulner-

As plants, animals, and diseases aremoved with increasing rapidity betweencontinents, humans are reversing morethan 100 million years of continentalisolation. Some are calling this periodthe “Homogocene.” I prefer the“Catastrophozic.”

Yellowstone Science10

able regardless of latitude, and I note thatsome of the most serious alien problemsin Yellowstone, such as lake trout, areaquatic.

By the way, the natural dynamics of aninvasion can lull us into complacency.For example, a new colonist may doubleits population size and the area it occu-pies each year, but this kind of growthmay appear to be negligible in the firstfew years as the alien expands, say, from1 meter of land to 2, then 4, then 8, then16, 32, 64, and so on. But if this contin-ues, during the twentieth year the alienwill gobble up a square kilometer of ter-ritory, and people will think that it hasundergone a sudden increase in growthrate when in fact they are witnessing anormal geometric expansion.YS: So the key is to find these invasionsites as early as possible?MS: Yes. I don’t know what NPS policyis on this, but if I were in charge, I woulddevelop four or five regional exotic teams,each of which was familiar with a par-ticular ecosystem. Maybe twice a seasonthose teams would patrol the roads in thecamp areas and pulloffs, find new sites ofinfection of particular exotic plants oranimals, and put a lot of effort into gettingrid of them before they spread, and thentrain local personnel in their manage-ment.

Potential Impact on Yellowstone

YS: One interesting twist on the Yellow-stone situation, at least with terrestrialplants, is that science has never shownthat the exotic plants are actually replac-ing native plants. And so the argumentgoes, what’s the big deal? Of course, thisdoesn’t apply to areas where the nativevegetation and soil have already beendisturbed by human activity; we have anumber of sites near the park and in thepark that were massively altered, say bya feedlot, where exotics take over andessentially create monocultures.MS: While it may be true that there is noevidence that a species has gone extinctin Yellowstone because of an alien intro-duction or colonization, there is no ques-tion that it’s happening in other places,and I think eventually it will happen here.Also, don’t forget that many new dis-eases are exotic species. And if a disease

is affecting a native tree that is an impor-tant source of food mast for the ungulatesor the carnivores, then the lower produc-tivity or abundance of that species as aresult of the disease can have a profoundeffect on the ecosystem even withoutcausing herbivores to go extinct. Thedemise of the American chestnut due tochestnut blight was such an event. So,local extinction of native species is notthe only criterion by which you shouldjudge whether an exotic species is havinga significant impact. I understand thatyou have a tree species that is beingaffected by a disease.YS: Right. The whitebark pine is suffer-ing to some extent from an exotic disease,blister rust. So far we don’t seem to be ashard hit as areas farther north of here witha different climate. Glacier National Park,in northern Montana, is apparently goingto lose virtually all of that species of treeover time. But you’re absolutely rightabout the effects of an exotic disease,because several of our fauna includinggrizzly bears, red squirrels, and Clark’snutcrackers are ecologically tied up withthe fate of the whitebark pine.

But there is another side to the exoticquestion. Say that an exotic grass invadedthe park, one that animals like to eat.Over time, it might fill in places betweennative plants, or even to some extentreplace the natives. It may have increasedthe nutritional potential of a range. Theresult could be that the animals “benefit”by having more food, but at the same timethe system has been altered, and of coursethe greater number of animals could haveeffects on other plants or other parts of thesystem. Philosophically, even if the planthas some short-term effects that don’tseem harmful, we must be very carefulhow we define such things as “harm” and“benefit.”MS: I think what the argument boilsdown to is the difference of opinion onwhat’s an acceptable rate in change. Theecological system in Yellowstone hasnever been a stable equilibrium system;it’s only been in existence a few thousandyears, which is no time at all biologicallyand ecologically. So the system is alwaysin flux. Besides, ecologists no longeraccept the paradigm of ecosystems ashomeostatic. And in the face of globalwarming, ozone thinning, and other

Blister-rust on the trunk of ayoung white pine.

changes such as the return of the wolf,there will continue to be an increase in therate of change.

So we are selecting among possiblescenarios. Where we have control, weshould probably exercise that control byeliminating the invading factors that causea grievous effect to the system. We don’thave the resources to eliminate every-thing that we may not like. So someexotic species might out of necessity betolerated, including a species that comesin but does not displace any native spe-cies, or does not have significant effectson the system’s productivity, or doesn’tserve as host for a more noxious species.We might even decide we can tolerate anexotic species that increases productiv-ity. But again, each time it’s a judgmentcall; it’s a matter of degree.

Alien Disease Organisms

YS: Most of us were raised on the “bal-ance of nature” concept. But as you

Fall 1996 11

us; an alternative approach in this era ofmassive biotic invasions from continentto continent is to look at the problemecologically. My personal litmus test fordetermining whether an alien should bedealt with or ignored is based on whetherit’s likely to cause the endangerment orextinction of native species that were partof the pre-European fauna of NorthAmerica. But it always comes down todifficult management decisions, and no-body is going to provide the NPS or anyother land management agency withsimple guide-lines or rules of thumb abouthow to deal with these problems.YS: Actually, there is a whole world ofposition takers and opinion holders outthere who are trying to do precisely that.There is an extraordinarily large group ofpeople who are certain they know what todo, and equally certain that science willback them up. The trouble is, from amanager’s perspective, none of them arepersuasive enough to win the debate.Perhaps that is what saves parks fromhaving too narrow a view of their mis-sion.MS: In these situations, your best hope isto gather together the best minds and sit

down and say, “Okay, we have a prob-lem. This group says this, another groupsays that, the public is saying this, themanagers are saying that. What shouldwe do?” Somebody is going to have tomake a decision and it’s never going to beclear-cut.

National Parks as Preserves for ExoticAnimals

YS: Another interesting idea that pops upnow and then, and not always out on thelunatic fringe, is that national parks aregood places for stockpiling species, evenif those species are not native to the park

pointed out, ecologists have abandonedthat simplistic view of how natural sys-tems work. The extent to which wildecosystems change without any obviouscause or direction is largely unknown tothe public—which still implicitly expectsthese places to be managed to arrest thechanges that have always been character-istic of wild systems. Look how workedup people got over the fires. But we’d liketo return to the issue of introduced dis-ease organisms, and get your impressionof what Yellowstone has to face in thatregard.MS: Look at it this way. Suppose wecould pick Yellowstone up and drop itinto Asia or Manchuria or Southern Af-rica. The result would be thousands ofinvasions. That is obviously farcical, butthe point of thinking about it is that Asiaand Africa are coming here, in the form ofmany species of plants, many species ofanimals, and many, many diseases. Andas the climate changes, in particular if theclimate warms as nearly all climatolo-gists predict it will, the rate of movementof pests and pathogens, including animalpathogens and parasites, will be greaterthan it is now. Already in the warmerparts of the United States we’re seeingincreasing populations of tropical mos-quitoes and other insects that harbor avariety of diseases, some of which willpose very serious human health threatssuch as malaria, yellow fever, and chagasdisease in the future.

This is not to say that we’re going to beseeing bananas and oranges growing inYellowstone in the next ten to twentyyears, but it will become warmer. Thatmeans that organisms that live in moremoderate climates will have a higher prob-ability of showing up here. Besides that,with the importation of exotic wildlife toNorth America for the enjoyment of hunt-ers and game ranching, there is alwaysthe possibility of increasing the move-ment of African and Asian diseases tothis continent, affecting our native fishes,waterfowl, and ungulates. So, I’m veryconcerned for the well-being of our wild-life.

I don’t know what we can do to plan forthese eventualities, but quarantine is cer-tainly an issue that we are concernedabout in the conservation and wildlifecommunity. I’m one of the most vocal

supporters of the concept of linking upour wilderness areas and national parksand roadless areas through the use ofinterconnecting wildlife corridors, so thatthe populations of wildlife will be viable.But the other side of the coin is that ifeverything is highly connected, patho-gens will move more easily too. Perhapswe need to have choke points within ourwildlife corridors.

Deciding Which Alien Species to Fight

YS: The NPS is struggling with a lot ofquestions relating to nativeness. Olym-pic National Park has gone through thepolitical and emotional equivalent ofWorld War III over their desire to get ridof non-native mountain goats that wereintroduced years ago. Olympic’s manag-ers weren’t just concerned about philo-sophical purity; those goats have tremen-dous impacts on native vegetation. Andother parks have big problems, like theferal burro populations in the Southwest.Here in Yellowstone, we’re being in-vaded by populations of mountain goatsthat were artificially established on pub-lic lands outside the park and are nowmoving onto parklands.MS: Those are im-portant issues, but ifthere were a simpleanswer to this, itwould have beenthought of a long timeago. Nativeness is oneof those concepts thatis always open to de-bate. By various defi-nitions, there are countless degrees ofnativeness or pristineness and, as yousuggest, the definition depends on whereyou draw your line, and the line is alwayssomewhat arbitrary. For instance, I couldargue that everything that was here priorto the arrival of Columbus is native, andeverything that came later is not. Or Icould say that everything that was herebefore humans arrived from Asia 10,000or 12,000 years ago, is native. All defini-tions are arbitrary to some extent, but thatdoesn’t make them less necessary forsome purposes.

I sometimes think that the issue ofnativeness is a red herring that distracts

My personal litmus test for determiningwhether an alien should be dealt with orignored is based on whether it’s likely tocause the endangerment or extinction ofnative species that were part of the pre-European fauna of North America.

Yellowstone Science12

in question. At its most reasonable (whichis giving more credit than it usually de-serves), this position would say, for ex-ample, that we would have a better chanceof saving the giant panda if we estab-lished “wild” populations in Great SmokyMountains National Park. Pandas areexotic, but if it were shown that theycould thrive there, maybe it would beworth the compromise of park values tosave this species.MS: Well, I don’t think that nationalparks should be botanic gardens or out-door zoos for exotic species. There areother agencies and other organizationsthat should provide those services. Na-tional parks should not be all things to allpeople. When an agency or a facility triesto do that, then they don’t do anythingwell. Besides, it is impossible to predictall the consequences of introductions.

I think it’s important that the adminis-tration and Congress and other policy-makers within the NPS bite the bullet andsay that this is our mission and thosethings are outside of our mission; some-body else must take care of them. Let’ssay that some temperate species of ungu-lates in southern Africa has become en-dangered. Maybe they could survive inYellowstone. But they might also carrydiseases, and their presence could have alot of other unknown consequences forthe carnivores and herbivores in the sys-tem. Stockpiling exotics opens aPandora’s box.YS: But you can understand how tempt-ing it must sound to some people, espe-cially those whom we describe as havingan especially strong husbandry gene.Let’s say, for example, that we couldeasily gather up all the different strainsand species of endangered pupfish thatlive in tiny isolated warmwater pondsand springs in the desert southwest. Wehave hundreds of warm pools here wherewe could give them additional homes,broadening their population bases andimproving their odds of survival if adisaster destroyed one pond.MS: But you know there are alwaysunpredictable ecological consequencesof doing things like that. By establishingnew populations of these fish, you wouldthen provide a new food source for somespecies of birds that specialize in feedingon small fish and prawns, but which don’t

exist here now. Suddenly an entirely newsuite of bird species might over-winter,bringing new diseases or parasites thatcould infect other birds. They could alsobring in seeds and spores of aquatic plantsthat don’t exist in the park. You neverknow what can happen. That is why therule of thumb is that no exotic speciesshould ever be consciously introduced.

What Distinguishes Yellowstone

YS: But we’d like you take a broader lookat Yellowstone. In the world of conserva-tion, we have the impression that Yellow-stone serves many purposes. A lot oftheory gets tested here, and a lot of newmanagement ideas are tried out, criti-cized, revised, and tested again. We al-ways have about half a dozen big contro-versies simmering along, and a lot ofsmaller ones, about the best way to man-age Yellowstone. From your global per-spective, what is it that distinguishesYellowstone as a site of conservation inaction?MS: One thing that distinguishes Yel-lowstone is that it contains virtually acomplete array of its native carnivoresand herbivores. The completeness of thissystem, and its scale, can’t be found inany other place in the lower 48 states.The sense of wilderness and wildnesshere is incomparable. If you’re walkinginto a forest and you know that there

might be mountain lions, grizzlies, orwolves nearby, it makes you that muchmore aware of your surroundings. You’remore alive and alert than you are in al-most any other kind of environment. Tosuddenly realize that one is a prey specieshelps us to appreciate our lives, particu-larly if a helicopter isn’t hovering over-head. In other words, wilderness teachesus lessons of humility and self-reliance.

Unfortunately, though, we’re comingto the end of the era when you were onyour own as soon as you left your car atthe trailhead. Soon most hikers in thewoods will carry a cellular or satellitephone. Such postmodern, backcountryecotourists will be able to down-load theWall Street Journal, phone their babysitter, or call in a helicopter rescue if theirGore-tex boots get damp. I’m saying thatcommunications technology means theend of the wilderness experience of itsusers. In a real sense, it means the end ofwilderness, period. Who wants to hear aphone ringing from the other side of thelake in a so-called wilderness?YS: So maybe we should ban cellularphones in the wilderness?MS: Indeed, but the government liabilitylawyers won’t permit it. They’re alreadyissuing phones to climbers in Denali.The best we can hope for is that grizzliesor wolves develop an irresistible fond-ness for the taste of these evil instru-ments. ❧

The wooly mullein (verbascum thapsus) a bienniel that is exotic toYellowstone.

NPS Photo

Fall 1996 13

Yellowstone’s Insect Vampires

insect nets as they fed from animals andhumans, or reared the insects from thedroppings of host animals.

My detailed field notes on insect activ-ity during this period were supplementedby observations and daily activity logskept during 1959-1961 and from 1990 tothe present. Most of my observationswere of large ungulates in the northernhalf of the park. Additional and oftenvivid comments were provided by parkpersonnel on the blood-feeding insectsthat made their lives more than a littleuncomfortable. Little or no informationseems to be available on the effects ofblood-feeding insects on other park ani-mals such as bears, coyotes, pronghornantelope, and bighorn sheep.

All of the flying insects in Yellowstonethat feed on the blood of vertebrates aretrue flies (order Diptera). In mosquitoes,buffalo gnats, biting midges, horse and

Biting to Survive

by John Burger

Yellowstone’s varied habitatsprovide a suitable environment for agreat diversity of insects and otherarthropods that depend on the blood ofbirds and mammals for their survival andreproduction. While often regarded aspests, these organisms are important com-ponents of their ecosystems. As larvae,they contribute to nutrient cycling inaquatic and semi-aquatic habitats, and asboth larvae and adults they provide foodfor a variety of predators and parasites.

This article summarizes the biologyand habits of each group of blood-feedingflies and ticks that inhabits the park, whereit is possible to study populations thathave not been affected by large-scale pestcontrol projects and habitat alteration.Much of the general information on bit-ing flies was gathered during the sum-mers of 1966 and 1967, while I wasstudying the association between insectsand bison, elk, and moose at the LamarRanger Station. I made direct observa-tions of these host animals and of horseskept at Lamar for backcountry work, col-lected insect specimens with standard

deer flies, and snipe flies, onlythe females feed on blood; males,

which feed on plant sugars for flightenergy, are short-lived and die soon aftermating. In horn flies, stable flies, andmoose flies, both sexes feed on blood.For most blood-feeding flies, blood isneeded for egg development. A few spe-cies can complete the first ovarian (orgonotrophic) cycle using nutrients storedfrom the larval stage, but subsequentcycles require a blood meal for egg matu-ration.

Mosquitoes

Of all Yellowstone’s blood-feeding in-sects, mosquitoes (family Culicidae) arethe most diverse and familiar to visitors.Most of the 33 species recorded in thepark are in the genus Aedes; species in thepark’s other three mosquito genera areinfrequently seen. The informa tion inthis article focuses on the 12 species ofAedes that are responsible for most of theannoyance to humans and other animalsin the park.

Yellowstone Science14

Life cycle. The females deposit theireggs in soil depressions where water willcollect during the spring and summer.The eggs remain dormant until they areflooded by water during snow melt orflooding in spring. The larvae, whichhatch in ground pools, feed on suspendedparticulate organic matter that they sweepinto their mouths with specialized mouthbrushes. They pass through four molts(instars), followed by an active pupalstage from which the adults emerge. Thelength of this part of the life cycle de-pends on water temperature, but usuallytakes about 4-6 weeks. After adult emer-gence, both males and females feed onplant sugars for flight energy, and matingsoon occurs.

After mating, females search for avail-able hosts, primarily large mammals.They are attracted by movement, CO

2,

heat, moisture, and volatile compoundson a host animal’s skin surface. Follow-ing a blood meal, the eggs mature in theovaries and are deposited in a suitablehabitat. Aedes produce only one genera-tion per year, and overwintering occurs inthe egg stage. The other three genera ofmosquitoes occurring in Yellowstoneoverwinter as larvae or adults.

Feeding. Although the onset of bitingactivity may vary by up to two weeksdepending on weather, it usually beginsduring the first week of June at lowerelevations. Generalizations about bitingactivity duration are difficult to make,partly because species tend to be typicalof either open sagebrush-grasslands(Aedes idahoensis) or forested areas(Aedes communis). In opensagebrush-grasslands in the northern partof the park, biting peaks during the lasthalf of June and in early July, while inforested areas and at higher elevationswhere larvae can be found in mid-July orlater, biting may not commence until lateJuly and may continue until early Sep-tember.

Host-seeking mosquitoes tend to bemost active in the evening and on cool,cloudy days, and less active during themiddle of the day or during warm, dry, orwindy weather. Activity tends to be stimu-lated after wet weather. The habits ofeach species are quite distinct. Some for-est species are very elusive, approachinga host cautiously and flying off quickly in

response to any sudden movement. Thesemosquitoes, while persistent, are hard tocatch. In contrast, species inhabiting thenorthern sagebrush-grasslands tend to bevery aggressive.

Distribution. Mosquito populationscan be relatively local or more generallydistri buted. Although biting populationscan be very large almost anywhere inYellowstone at a particular time, someareas such as the Lamar Valley, SodaButte Creek, and Slough Creek are noto-rious for mosquitoes because of exten-sive breeding habitat, especially in lowspots where water accumulates after snowmelt and spring flooding. Biting popula-tions can be so dense that they driveanglers and hikers indoors or to the ref-uge of their vehicles. In early July, Aedesidahoensis can attack in dense clouds inLamar and near Soda Butte. On one earlyevening, dark horses being loaded at theSoda Butte trailhead appeared gray be-cause of the light reflecting from thewings of feeding mosquitoes. In springand early summer, Bechler Meadows haslarge flooded areas where mosquitoescan become pestiferous until the wet spotsdry up in August. Spring flooding alongthe Yellowstone River in the Thorofarearea also produces large mosquito popu-lations.

Effect on Animals. Deer, elk, bison,and other large mammals are suitablehosts for many mosquito species, butlittle is known about whether these ani-mals’ behavior or health is seriously af-fected. Mosquitoes probably remove sig-nificant quantities of blood, but animalsmay avoid the most severe attacks bymoving to areas where mosquitoes areless abundant. Dense pelage on bisonmay limit mosquito attacks to areas of thebody where hair is short, sparse or absent.Mosquitoes are known to transmit avianhaematozoa (blood parasites) to birds andprobably do so to at least some extent inYellowstone. One species of Culex knownto occur in Yellowstone feeds exclusivelyon frogs.

Horse Flies andDeer Flies

After mosquitoes,horse flies and deerflies (family Tabanidae) are the most

diverse and conspicuous biting flies inYellowstone. Of the 31 species recordedin six genera in the park, the most abun-dant and widespread are in the genusChrysops (deer flies) and the genusHybomitra (horse flies). Deer flies aresmaller (6-8 mm long), and in Yellow-stone are either black or yellow and black.All deer flies have a conspicuous darkcrossband on the wing. They often areconfused with snipe flies, which are gray,brown, or black and have unpatternedwings. Horse flies are larger,heavy-bodied flies (12-18 mm long) thatare gray, reddish brown, or black.

Life Cycle. Masses of 100-400 horsefly and deer fly eggs are laid on emergentvegetation near the edges of ponds andother areas of standing water such asmarshes and sloughs. When the eggs hatchin 3-4 days, the larvae drop into the water,burrowing into the soil beneath it. Thelarvae pass through 6-8 molts beforemoving to drier adjacent soil to pupate.The larval stages of deer flies last about ayear, while those of larger horse flies maylast one to three years, depending on foodavailability. Both horse fly and deer flylarvae prey on soft-bodied organisms,and will generally consume any organ-ism they can overpower, including eachother. The pupal stage lasts about 8-14days, followed by adult emergence. Over-wintering always occurs in the larval stage.

Studies have shown that only about 40percent of the deer flies that survive topupation emerge as adults; the remainderare killed by parasites or pathogens suchas viruses, bacteria, microsporidia, andfungi. Adult emergence usually beginsthe last week of June, but may be ad-vanced or delayed by a week or moredepending on the weather. The flies rap-idly become more abundant and peak inmany areas of the park by the third weekof July, starting at lower elevations. Al-though the flies may remain locally abun-dant at higher elevations, activity gradu-ally begins decreasing by mid-August,and usually ceases by the first half ofSeptember, depending on weather condi-tions.

Deer flies appear to alternate annuallybetween high and low populations inYellowstone, perhaps because predatorsor parasites are favored by particular en-vironmental conditions, or because deer

Fall 1996 15

fly pathogens are more common in someyears.

Feeding. Horse flies and deer flies aremost active on warm, sunny days be-tween 10 a.m. and 4 p.m. and less activeon cloudy or cool days or during rainyperiods. These flies are strongly visuallyoriented, and usually depend on hostmovement for long-distance attraction,and on host odors, color, and CO

2 for

close attraction. Their blade-like mouth-parts for piercing and cutting throughskin can produce very painful bites. Deerflies tend to be most common in mead-ows or along trails, where they perch onvegetation and fly out and around objectsmoving on the trail. They usually circleonce or twice while determining whetherto land and attempt to feed. Horse fliesalso rest in vegetation and fly out aftermoving objects, particularly in open ar-eas. Trails and large meadows are primelocations for Chrysops ful vaster, a vi-cious biting deer fly that is extremelyabundant in large meadows and near somethermal areas.

Effect on Animals. Little is knownabout the effect of horse flies and deerflies on Yellowstone’s wildlife popula-tions. Although the fierce bite of Tabunuspunctifer, which has a large black bodywith a gray thorax, can cause horses tospook, the species is not common in thepark. Deer fly bites have been known tooccasionally transmit tularemia to hu-mans, and horse fly bites have transmit-ted anaplasmosis to Wyoming mule deer.In the Southwest, horse flies transmitelaeophorosis, a serious filarial wormdisease of elk, but it has not been reportedin Yellowstone.

Horse flies can cause significant bloodloss in livestock, resulting in a reductionin weight gain of up to a kilogram a day,and this probably occurs in park ungu-lates as well. If not “fly doped” severaltimes a day or kept in the barn, horsescorralled at Lamar Ranger Station hadblood oozing from multiple bites, whichattracted other flies that feed on blood.Bison may use dust wallows to reduceattacks of biting flies, but this is probablysecondary to other reasons for wallowuse. Elk will sometimes bunch togetherwith heads pointing inward, or line upwith heads facing in opposite directionsin what appears to be a kind of collective

response to attacks of horse flies, but thiscould also be to avoid parasitic nasal botflies. Yellowstone’s large mammals un-doubtedly experience considerable an-noyance during the horse fly season whichcan be mitigated by moving to a higherelevation or seeking shelter in dense for-ested areas during the day.

Snipe Flies

Biting snipe flies(family Rhagionidae)are slender-bodied, gray, brown, or blackflies with long, unpatterned wings andshort piercing mouthparts. All the bitingspecies in Yellowstone belong to the ge-nus Symphoromyia. Their attack behav-ior is similar to that of deer flies, withwhich they are often confused, and theyare sometimes referred to as “deer flies”or “buffalo flies.” The most commonspecies inhabit either open sagebrush-grassland areas (Symphoromyiaflavipalpis) or forested areas(Symphoromyia pachyceras).

Feeding. Snipe flies are not as gener-ally distributed or as consistently abun-dant in the park as horse flies, deer flies,and mosquitoes, and they tend to be ex-tremely local in distribution. They aremost common in northern Yellowstoneand in large, open expanses such as Hay-den Valley. They may be abundant in aparticular small area for only a few days.The factors governing the occurrence ofthese flies and their abundance duringoutbreak years are not known. Whenvery abundant, snipe flies can be severelyannoying to humans, attacking in largenumbers around the head and arms, witha particular predilection for wrists andfingers, resulting in painful bites. In cer-tain years, such as 1994, adults have beenextremely abundant, with 25 or moreflies attacking simultaneously. They at-tack silently, often going unnoticed untila sharp stab heralds their penetration ofthe skin.

Effect on Animals. When especiallyabundant, snipe flies may cause largeanimals to move. Snipe flies that areactive in open areas tend not to move intoforested locations, and forest species donot often attack in large meadows, soanimals can avoid the most severe attacksby moving to areas where the flies are less

active. The extent to which snipe fliesmay transmit diseases or parasites to wild-life is not known.

(For a more detailed account of snipeflies in Yellowstone, see Yellowstone Sci-ence Spring 1995 3(2):2-5.)

Buffalo Gnats or Black Flies

Buffalo gnats (familySimuliidae) are small,heavy-bodied flies with piercing mouth-parts similar to those of horse flies andbiting snipe flies. “Buffalo gnat,” whichis the name used commonly in the West,refers to the humped appearance of thethorax. Many species are predominantlyblack with some paler markings. Exten-sive surveys of buffalo gnats in the parkduring the past four years have recorded30 species in four genera, mostly in thegenera Prosimulium and Simulium. Ex-cept for those originating in thermal ar-eas, every stream examined in Yellow-stone has been found to support at least afew species.

Life Cycle. Females deposit their eggssingly or in groups in running water,either by scattering eggs over the watersurface or attaching them to vegetation orrocks in a stream. Species of Prosimuliummay overwinter as larvae or eggs, whileSimulium species overwinter only as eggs.The elongate larvae, which attach to rocksor vegetation in streams, have head “fans”that filter particulate organic matter fromthe water column. Pupation occurs on thesame substrates that are inhabited by thelarvae. Emerging adults ride a bubble ofair to the water surface and fly to shore.Mating usually occurs near the larvalhabitat.

Adults begin emerging in late June andrapidly increase in abundance throughJuly and early August. Because somespecies may have several generations peryear, large populations can be found evenin early September. A CO

2-baited canopy

trap in the upper pasture at Lamar col-lected thousands of female Simuliumarcticum on September 6-9, 1966. Fortu-nately for humans, buffalo gnat popula-tions in the park tend to be quite local.Some species inhabit large rivers such asthe Yellowstone and the Lamar, whileothers live in cold springs and tiny watertrickles running down hillsides. Some

Yellowstone Science

Biting Midges

Biting midges( f a m i l yCeratopogonidae),commonly called punkies or no-see-ums,are minute flies whose painful bites arewildly disproportional to their size. Theygenerally have dark-colored chunky bod-ies and faintly mottled wings with palespots. The genus Culicoides is respon-sible for most biting activity in Yellow-stone. These are the least studied ofYellowstone’s blood-feeding insects, andlittle is known about the number of spe-cies present or their life cycle. The larvae,which are slender and elongate with awell-developed head capsule, occur inwet or damp soil, usually where muddyareas persist for considerable periods.Larvae are carnivorous as far as is known.The mouthparts of the adults are similarto those of buffalo gnats, horse flies, andsnipe flies.

Feeding. Biting female midges areactive from early July to early Septem-ber. Large populations tend to be ratherlocal, and adults probably do not dispersefar from their breeding sites. The midgesare most active at dusk, and large num-bers may suddenly attack when decreas-ing light intensity reaches a critical levelfor activity, causing considerable annoy-ance. Biting activity usually lasts untilabout 9 p.m., when the air temperaturebegins to drop rapidly. I have observed150-200 midges attacking horses whenpastured in or near wet areas in tall grassat dusk. Feeding midges, which appearas dark or pale grayish specks on the skin,are not capable of penetrating clothingbut pass readily through screened win-dows. One of the most common bitingspecies in Yellowstone is Culicoidescockerelli.

Effects on Animals. Serological evi-dence suggests biting midges transmitbluetongue virus, a serious disease ofdomestic sheep, to elk, mule deer, andpronghorn in Wyoming. They also trans-mit epidemic haemorrhagic disease,which has been recorded in white-taileddeer and pronghorn antelope. Some spe-cies are known to transmit filarial wormparasites to large mammals.

16

species occur in dense populations whileothers are widely scattered over largeareas of stream bottom. The most favoredareas for adults seem to be in tall grassadjacent to streams; they are rarely abun-dant in upland areas away from streams.

Feeding. After mating, females searchfor suitable hosts. Particular species tendto feed on either birds or mammals, butnot on both. The females usually crawl onthe host before biting. When attackinghumans, they often burrow beneath trou-ser legs, socks, and shirt cuffs, or bite atthe back of the neck at the hair line.Host-seeking females are most active oncool, humid days during late morning andlate afternoon to early evening; bitingactivity increases during and just afterwet weather. Some species have rela-tively painful bites, while others produceno initial reaction at all. Often a spot ofblood remains where a fly has pierced theskin. Bites can cause severe allergic reac-tions in some people, but this is unusual.

Effect on Animals. Buffalo gnats canbe serious pests of humans and largemammals, especially in northern areasand in the mountains of the West. Somespecies known from Alberta andSaskatchewan, Canada, can cause severeallergic reactions in cattle, which may diefrom a large number of bites. Observa-tions of horses at Lamar in the 1960sshowed that adults of Simulium arcticum,one of the park’s most abundant species,burrow under the hair of the animal, par-ticularly on the neck, chest, and betweenthe front legs. Running a hand over thechest of a horse can cause a hundred ormore feeding buffalo gnats to drop out ofthe hair. The insect bites form large bloodywelts that turn into swollen scabbypatches. Although horses do not seem totry to avoid them, possibly because of thegnats’ small size and quiet approach,some horses are known to be especiallysensitive to them. Large mammals arepresumably heavily exposed to bitingbuffalo gnats where species such as Simu-lium arcticum are abundant, but effectson the health and behavior of the hostanimals are not known. Buffalo gnats cantransmit a blood parasite (Leucocytozoon)to waterfowl, but the presence of thisparasite in Yellowstone is undetermined.

Biting Muscoid Flies

Although theseflies belong to thesame family (Mus-cidae) as the housefly, their mouthpartsare modified for piercing and feeding onblood. Yellowstone has three species ofbiting muscoid flies (subfamilyStomoxyinae): the horn fly (Haematobiairritans), the stable fly (Stomoxyscalcitrans), and the moose fly(Haematobosca alcis). The horn fly andthe moose fly are host-specific to bisonand moose, respectively, in Yellowstonewhile the stable fly is a generalist, feed-ing on many large mammals.

Horn Fly. This blood-feeding fly fromthe Old World spread rapidly throughoutmost of North America after its introduc-tion here around 1885. Dark brown andabout half the size of a house fly, adulthorn flies have a slender, elongate pierc-ing proboscis. This fly and its relatives inEurasia and Africa feed on Bovidae suchas cattle and buffalo. The name horn flywas given to this species because of themistaken impression that they clusteraround the horns of cattle.

Adult horn flies live on Yellowstonebison, primarily on the animals’ backs,where they feed on blood frequently. Ifdisturbed from the bison, they immedi-ately fly back to it. Up to 200-300 fliescan be found on a single domestic animal,but whether they reach this density onwild bison is not known. As soon as abison defecates, the females fly onto thedropping, each stabbing 5-10 eggs be-neath the surface. After five minutes whenthe dung is no longer attractive to thefemales, they return to the host. Larvaedevelop in the droppings for about 2-3weeks, then migrate to the soil to pupate.When adults emerge, they search for asuitable host or wait until the animalsvisit the area.

Adult horn flies are of considerableeconomic significance to ranchers be-cause they lessen weight gain in cattle.They may occasionally feed on a horse orland on other animals, including humans,but they rarely attempt to feed on unsuit-able hosts. Their numbers gradually in-crease starting in late June, and probably

Stable fly

Fall 1996

be apt to pick up more questing ticks fromvegetation.

The winter tick is not known to trans-mit any diseases to wildlife, but its largenumbers on elk, antelope, deer, and otherlarge mammals that are physically stressedin winter would undoubtedly contributeto their mortality.

Rocky Mountain Wood Tick. As a“three-host” tick, the Rocky Mountainwood tick has a very different life cycle.After hatching, the larva feeds on a smallmammal such as a ground squirrel, thendrops off and molts to the nymph stage.The nymph feeds on another small mam-mal the following year, then leaves thathost and molts to the adult stage. Thefollowing year, it seeks a large mammal,which could be a human, although suchticks seem to be relatively rarely encoun-tered. After feeding, the female lays up toseveral thousand eggs and then dies. InYellowstone, adults are active frommid-April to mid-May and are most preva-lent in large meadows and insagebrush-grasslands.

The Rocky Mountain wood tick trans-mits several dis-eases, including tu-laremia and RockyMountain spottedfever, which wasonce common inFlathead Valleyand the BitterrootMountains of Mon-tana but is now much less so because ofchanges in land use and a shift in thepathogen’s virulence. The Rocky Moun-tain wood tick has been implicated in thebiological transmission of anaplasmosisto mule deer in Wyoming. Brucella or-ganisms have been detected in ticks, butno evidence of transmission to animalshas been demonstrated. This wood tickcan cause a slow-spreading paralysis thatis a reaction to the saliva of a feeding tickwhen it bites on the scalp or back of theneck; the paralysis disappears when thetick is removed.

Lyme Disease. Currently the most se-rious tick-borne human disease in NorthAmerica, Lyme disease has not yet beenreported in Montana. Thirty cases havebeen reported in Wyoming since 1989,but the presumed western vector (Ixodespacificus) has not, raising the possibility

peak in late August or early September.Stable Fly. This biting fly, which has

relatives in Asia and Africa, was prob-ably introduced into North America some-time after the arrival of European immi-grants. It is sometimes called the “bitinghouse fly” because it resembles the housefly except for its slender, elongate pro-boscis. Immature stages live in moistdecaying vegetable debris, including matsof dead grass or animal droppings mixedwith vegetable debris. The larval stageslast 2-4 weeks, depending on tempera-ture. Mature larvae move to drier sub-strates for pupation. After emergence,adults mate and then search for a suitablehost.

Stable flies tend to attack the lower partof the body, especially the legs and anklesof horses and other large mammals. Be-cause their approach is silent, stable fliesoften remain undetected until they pen-etrate the skin. Close observation revealsthe black proboscis searching for a likelyfeeding spot. The elongate mouthpartscan readily penetrate clothing. The bitesare quite painful, and animals react bystamping their feet. As with the horn fly,stable fly populations gradually increaseduring the summer months and are mostabundant in August and early September.Adults are active during daylight hoursuntil dusk.

Moose Fly. I conducted the only de-finitive study of this fly in Yellowstone inthe 1960s. This fly is similar in manyrespects to the horn fly, except it is nativeto North America. It depends on a singleanimal species for its entire life cycle,which is unusual for a blood-feeding fly.While its Eurasian relatives are associ-ated primarily with cattle and their rela-tives, in North America it occurs wher-ever moose are found. Adults remain onthe moose’s hindquarters, feeding fre-quently except when females leave to laytheir eggs. When a moose crosses a stream,the flies hover over the animal until itemerges from the water, then they imme-diately land on it again.

When a moose defecates, the femalesimmediately leave the animal and walkacross the dung surface, stabbing eggsinto crevices. About 5-10 flies will lay50-75 eggs on a dropping. The flies re-turn to the moose to resume feeding after2-3 minutes, as other dung-inhabiting

insects begin arriving at relatively spe-cific intervals, thus partitioning access tothe resource. Moose flies may completeup to three generations a year under fa-vorable environmental conditions, butonly the softer droppings characteristicof late spring and summer will supporttheir development. The larvae pupate af-ter about 3-4 weeks. Adult flies emergefrom the pupa about 4-5 weeks after theeggs have been deposited and then rest invegetation until moose move into thearea. Larvae present in September pupateand remain dormant until the adultsemerge the following June and early July.

I have not noticed any adverse effectson moose, which do not seem to be espe-cially bothered by the flies, even with200-300 flies per animal in mid-summer,although blood loss must be considerablein such cases. I have occasionally col-lected adult moose flies on horses, andonce a male bit me on the arm, producinga sensation like a mild pinprick. Theseflies were probably seeking a suitablehost animal and were attracted by move-ment.

Ticks

The two mostcommonly encoun-tered species of ticks(family Ixodidae)are the winter tick( D e r m a c e n t o ralbipictus) and the Rocky Mountain woodtick (Dermacentor andersoni) althoughother species likely appear in the park.

Winter Tick. Active during winter andearly spring, the winter tick is a “one-host”tick, remaining on its host as it developsfrom larva to nymph to adult. It occurs onmany large mammals, including elk, deer,moose, bison, and antelope, but not onhumans. Unlike most ticks, the wintertick can occur in very large numbers on ahost. Some hosts that carry hundreds oreven thousands of ticks are almost invari-ably in poor condition and are likely todie during the winter. Although the rela-tionship between the physical conditionof the host animal and the number ofwinter ticks present has been observedfor many years, no explanation has beendocumented. Because animals in poorcondition are more sedentary, they may

winter tick Rocky Mountain tick

17

Yellowstone Science

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18

Fall 1996

➤

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may also have had greater access to theordinarily isolated pools in which mos-quitoes breed in large numbers, this wouldnot be the case for mosquitoes in isolatedsnowmelt pools in forested areas that arenot as subject to flooding and other dis-turbances. Very wet soil conditions mayhave reduced the survival of horse fliesand snipe flies in some areas. Buffalognats breeding in the Yellowstone Riverhatched much later than usual and grewvery slowly, possibly reducing the adultpopulation and the number of genera-tions emerging this year. The respite fromthe annual onslaught of blood-feedinginsects, while welcome to most of us, isprobably temporary, and we can lookforward to healthy populations of theseinsects in future years.

Reducing Annoyance byBlood-Feeding Insects

Three strategies can be used to mini-mize exposure to blood-feeding insects:using protective clothing, using repel-lents, and avoiding places when and wherepesky insects are active. Avoidance iseasiest for snipe flies, deer flies, andbuffalo gnats, which tend to be locally

that these cases were contracted else-where. The species of ticks known tooccur in Yellowstone have not been im-plicated in Lyme disease transmission.

The Peculiar 1996 Season

The summer of 1996 proved to be anextremely unusual one for blood-feedinginsects in Yellowstone, when heavy snow-pack and rains in late winter and springproduced record water levels and floods.Mosquitoes in the Lamar and SloughCreek drainages were exceptionallyscarce, less than 1 percent of “normal”nuisance populations, and this apparentlyoccurred in other areas as well. Snipeflies were absent from all investigatedareas, including those where they areusually moderately to extremely abun-dant, and horse flies and deer flies ap-peared to be much reduced. Trail crews inthe Lamar backcountry reported anear-absence of the usual plague of bitingflies that can make their work so uncom-fortable.

In the case of mosquitoes, it seemslikely that high water may have flushedout their usual breeding sites near riversand larger streams. Although predators

abundant during certain times of the year.For insects that are more generally dis-tributed, protective clothing and repel-lents are more effective, keeping in mindthat snipe flies, deer flies, and horse fliesare most active during dry periods, andon warm, sunny days during daylighthours, while buffalo gnats, mosquitoes,and biting midges are most active duringlate afternoon and evening hours and oncool, cloudy, or humid days.

Protective clothing, which works bestagainst mosquitoes, buffalo gnats, andbiting midges, includes shirts with longsleeves, broad-brimmed hats, long pants,and heavy socks. A bandanna behind thehead tucked into a hat will keep buffalognats and deer flies from attacking aroundthe head and neck.

Commercially available repellents canbe used to eliminate or reduce attacks byblood-feeding flies. A bewildering arrayof these products claim to work, but dif-ferent formulations and concentrationsof a particular repellent can vary widelyin their effectiveness. Length of protec-tion is related to the concentration of theactive ingredient in the product. Whileconvenient and useful for treating cloth-ing, sprays are generally not as persistentas lotions. Repellents containing “DEET”(diethyltoluamide) are effective againstmosquitoes, biting midges, and to someextent, buffalo gnats, but not against horseflies, deer flies, and snipe flies; for these,repellents containing citronella seem towork better but must be applied morefrequently.

It is well to remember that despite theirunpleasant traits for humans,Yellowstone’s insect vampires were herelong before humans arrived and are likelyto still be here long after humans havepassed from the scene. Perhaps one can atleast appreciate their role in nature, if nottheir predilection for blood.

Dr. John Burger is professor of zoologyat the University of New Hampshire,where he specializes in blood-feedingflies. Since 1990 he has been document-ing the growth and succession of post-firevegetation and selected insect popula-tions at sites in northern Yellowstone,sacrificing much blood in his quest forknowledge.

The developmental stages of the tick.

19

Yellowstone Science

&notesNEWS

President Announces Settlement onNew World Mine

With a backdrop of Barronette Peak inYellowstone, on Monday, August 12,President Bill Clinton announced anagreement between Crown Butte Mines,environmental groups, and federal agen-cies that would stop a massive gold, sil-ver, and copper mine just outside parkboundaries. Leaders of conservationgroups and agencies battling the pro-posed New World Mine hailed the settle-ment as a major victory for the environ-ment and a way to forever protect Yel-lowstone from mining pollution in thisarea. President Clinton gave his speechto nearly 300 persons saying that theagreement “proves that everyone canagree that Yellowstone is more preciousthan gold. We are all protected fromyears of and years of expensive and bitterlitigation. And while there is still work todo, and work in which members of thegeneral public must and will be involved,we are going to move forward. And thissigning today means that it will come theway so many of you have worked for, forso many years. I also want to say that theway this was done should become a modelfor America’s challenges, not only in theenvironment but in other areas as well.”

Environmental groups that had suedCrown Butte over pollution draining fromthe companies mining lands agreed todrop their lawsuit, while federal and stateagencies will suspend work on an envi-ronmental impact statement assessing theeffects of the mine, and Crown Buttemust cease all exploration and other min-ing activity. Crown Butte will also place$22.5 million into a special account thatwill pay for the company’s continuingcleanup of historical mine waste on itsholdings. In turn, federal agencies willgive Crown Butte $65 million worth ofproperty yet to be identified through aprocess which will include public com-ment. The agreement was designed tocompensate shareholders for their invest-ments, provide strict protection for parkresources and, in doing so, respect bothprivate property rights and the sanctity ofYellowstone National Park.

Wolf Population Continues to Grow

On August 29, three female pups andone male pup from the Sawtooth wolfpack near Augusta, Montana, were trans-ferred to and temporarily penned in thepark. On September 8, six more pupswere captured and joined their siblings atthe Rose Creek pen. Adults from thispack had killed livestock and were theremoved according to wolf managementguidelines for the Rocky Mountain Frontarea. The pups were placed with the twoNez Perce yearlings being held in theRose Creek pen. It is hoped that theyearlings and pups will form a new pack.Plans currently call for these wolves to beheld for the winter and released in spring.

Two wolves penned temporarily at NezPerce were released on September 17when a yearling female began to frequentthe area outside the pen, possibly forminga bond with the older male inside. Thepenned wolves, a young adult male origi-nally of the Soda Butte pack and a malepup from the Nez Perce pack, had beencaptured and relocated from private prop-erty near Nye, Montana. Neither wolfhad preyed on livestock, but it was be-

lieved that relocation to the park wouldprovide the wolves better habitat. Unfor-tunately, the younger male was founddead on September 21, apparently theresult of a roadkill.

The wolf pair originally penned at NezPerce separated upon their release inspring, and never reunited. The alphafemale settled north of the park with fivepups born this spring and, when she be-gan preying on livestock, repeated at-tempts were made to capture her. Thoughthese efforts were unsuccessful and wereterminated in August, one of her malepups was injured during capture opera-tions. The pup subsequently had a legamputated and was placed into captivityat the Wildlife Science Center in ForestLake, Minnesota.

The Soda Butte pack has been pennedall summer due to concerns about poten-tial livestock predation on private landswhere they had denned this spring. OnSeptember 3, one of this year’s pups wasfound dead by biologists during a sched-uled feed; the cause of death is yet to bedetermined. The five remaining wolveswere penned at Trail Creek south of Yel-lowstone Lake from August until Octo-ber 7, when sections of their pen wereremoved to permit their release.

Wolves in the Druid Peak, Leopold,Chief Joseph, Rose Creek, and CrystalBench packs continue to roam in andoutside park boundaries, and have pickedup some new wolves from other packs,while two sets of wolves who ranged asloners during summer have newly pairedand at last report were in the Thorofarearea. Free-ranging wolf packs and lonershave not been involved in any livestockdepredations and continue to provide oc-casional opportunities for visitors to seeor hear them.

Record Year for Grizzly Bear Cubs

Grizzly bear reproduction, as evidencedby annual counts of unduplicated femalesseen with cubs across the greater Yellow-stone ecosystem, was at record levels in1996. Through October 1, biologists hadobserved a total of 33 sows with 70cubs-of-the-year (average 2.1 cubs perlitter). The highest number of grizzlybear sows with cubs previously counted

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NPS photo

News & Notes

Fall 1996

&notesNEWS

was 25 in 1986. The highest number ofcubs of the year previously counted was57 in 1990. Whitebark pine nuts werevery abundant in most areas of the eco-system this year, holding bears at higherelevations away from most human activ-ity and developments. There was onlyone grizzly bear-human conflict reportedin the park in 1996 and no bears have hadto be trapped and translocated within orremoved from the park.

Record Fire Season in WestComparatively Quiet in Yellowstone

Wildfire activity throughout the west-ern United States was reported to haveburned more acreage in 1996 than even inthe record year of 1924 (1988 being a

PEOPLE AND PLACE:THE HUMAN EXPERIENCE IN GREATER YELLOWSTONE

Fourth Biennial Scientific Conference on the Greater Yellowstone EcosystemSeptember 28-30, 1997

Mammoth Hot Springs Hotel, Yellowstone National Park

“No place is a place until things that have happened in it are remembered inhistory, ballads, yarns, legends, or monuments.” —Wallace Stegner

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he next in a series of conferences to feature the presentation of research on the region’s cultural and naturalresources will be held on September 28-30, 1997 in Mammoth Hot Springs. People and Place: The HumanExperience in Greater Yellowstone invites proposals for papers and panel sessions from the disciplines of

American studies, anthropology, archeology, cultural and historical geography, economics, ethnography, history,literary and art criticism, philosophy, political science, and sociology on topics related to greater Yellowstone.

One-page abstracts (hard copy and disk) and requests for more information should be submitted to JoyPerius, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190.

Or look for the World Wide Web site at http://www.nps.gov/yell/ycr.htm.

T

record for Yellowstone National Park),but Yellowstone experienced only 13 pre-scribed natural fires that burned a total of3,264 acres, and 10 wildfires that weresuppressed and burned a total of 3 acres.The largest single fire in Yellowstonewas the Coyote Fire, which started June26 in the northern part of the park. Jointlymanaged by the National Park Serviceand the Forest Service, the fire was al-lowed to burn across agency boundaries,and as of September 17 had burned 1,169acres inside the park and 2,594 acres inthe adjacent Gallatin National Forest. ThePelican Fire burned 1,570 acres and pro-vided good viewing opportunities for visi-tors driving along the East Entrance Roadand those hiking around or boating onYellowstone Lake. By late September, afew fires were still smoldering, but cold

weather and precipitation had reducedthe fires to minimal activity.

Visiting Scholar Todd Fuller Workswith Wolf Project

Dr. Todd Fuller of the University ofMassachusetts arrived in Yellowstone inSeptember to spend six weeks as a Vis-iting Scholar. Fuller is at the forefront ofresearch on wolf population dynamics,and during several decades of wildliferesearch has also had the opportunity tostudy carnivores in Africa and SouthAmerica. Biologists are honored to haveDr. Fuller in the park collaborating andassisting with the wolf project, and healso presented several talks for park staffon carnivore conservation in other eco-systems of the world.

BULK RATEPOSTAGE & FEES PAID

National Park ServiceDept of Interior

Permit No. G-83

Yellowstone ScienceYellowstone Center for ResourcesP.O. Box 168Yellowstone National Park, WY 82190

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stone’s Insect Vampires

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