A Monthly Newsletter of Environmental Science and Policy · the Coon Creek basin for an intensive study of soil erosion that involved surveys throughout the basin, land use studies,

Environmental ReviewA Monthly Newsletter of Environmental Science and Policy

Volume Seven Number One January 2000

CONTENTS:

SOILCONSERVATION

AND SOIL EROSIONIN THE UPPER

MIDWEST:Stanley Trimble

CLIMATE CHANGEAND

EMERGING MARINEDISEASES:

Drew Harvell

A Long A Long A Long A Long A Long TTTTTerm Studerm Studerm Studerm Studerm Stud y ofy ofy ofy ofy ofSoil ErSoil ErSoil ErSoil ErSoil Er osionosionosionosionosion

Introduction:

Coon Creek in Northern Wiscon-sin drains about 360 square kilometersof rolling hills and bottomlands andempties into the Mississippi River nearLaCrosse, Wisconsin. In the 1930sduring the Depression and Dust Bowl,the Soil Conservation Service chosethe Coon Creek basin for an intensivestudy of soil erosion that involvedsurveys throughout the basin, land usestudies, and aerial photography.

In the 1970s and again in the1990s, Stanley Trimble and othersreturned to the Coon Creek basin tomeasure how the land had changed inthe intervening years. In many casessoils had moved from upland farms tobecome sediments in stream beds,stream channels had widened andmoved, terraces had become swamps,swamps had grown up into forest. Byrepeating and extending the 1930ssurveys they were able to estimate theamounts and rates of soil erosion thathad occurred in the basin during theprevious half century.

To extend their study further backin time, they dug down to markers ofthe first European settlements such asmill dams, house foundations, and oldroad beds; digging deeper, theylocated the original prairie soils datingto the 1850s when European farmersfirst settled the area.

Although farming started in theCoon Creek basin in the mid 19th

century, soil erosion was not serious

until around the turn of the century.After 1900 soil erosion increaseddramatically, peaking in the DustBowl of the 1930s. Soil erosiondecreased as farmers adapted soilconservation practices. Soil conserva-tion techniques have continued toimprove and recent rates of soilerosion in the basin are about 6percent of what they were during the1930s.

Trimble’s paper has generatedcontroversy within the academiccommunity, which is a sign of animportant contribution. ProfessorTrimble assured a warm receptionwhen he concluded his paper with a

mild challenge to the conventionalwisdom: “The processes occurring onCoon Creek are indicative of manyagriculturally disturbed basins in theU.S. and elsewhere.”

How far these results can beapplied to other watersheds is asubject of debate, but the extraordi-nary depth and breadth of this workshould provide a benchmark by whichother soil studies can be measured.

ER: Professor Trimble, what is yourtraining?

ST: As an undergraduate I had achemistry major with minors inphysics and math. I had intended to bean engineer, but the school I attendeddid not have an engineering programso I just finished in chemistry. In theensuing years of military service andtravel I realized that I was interestedin landscapes, especially in the humanelement of the landscape. I’d beenliving in Europe so I came back to thiscountry and did another bachelor’sdegree, this time in geography. Then Ienrolled in graduate school at theUniversity of Georgia, where I did aPh.D. in essentially human geography,interested particularly in humansettlement and population patterns. Itwas during graduate school that Irealized that I was more interested inhow humans had changed the physicallandscape.

ER: Almost an archeology kind ofapproach?

ST: Well, more of a demographicapproach you might say: looking at for

2

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Board of Directors:

Douglas Taylor, Ph.D. presidentScott Jamieson, O.D. vice presidentProfessor Estella Leopold, secretary

Carol Marquess, treasurerState Senator Ken Jacobsen

John MacdonaldThomas Geiger

example, how people settle the land,how they take up agriculture, how alandscape develops over time.

I had done a master’s thesislooking at soil erosion in the SouthernPiedmont, so when the time came todo a dissertation, I went back to that. Ihad to pick up a lot of agronomy,geology, and hydrology along theway. That dissertation was publishedby the Soil Conservation Society ofAmerica, and it elicited quite a lot ofattention.

ER: What is the southern Piedmont?

ST: The Piedmont is a foothills regionthat extends all the way from Alabamato Virginia. It’s a huge chunk of land,big as most states.

After graduate school I accepted aposition at the University of Wiscon-sin at Milwaukee. I had done mygraduate work in Georgia, and sothere I was in the upper Midwest, andI said, Well I’m here, I might as welllook for projects here.

Through a friend — StaffordHapp, a retired geologist — I foundout about a series of stream projectsthat were conducted back in the1930s, and one of those was on CoonCreek. I found out that Happ andothers had done a lot of work in thisgeneral region, the upper MississippiRiver hill country, more generallycalled the driftless area, it’s theunglaciated part of the upper Midwest.

So in 1973 I reconnoitered thearea and was taken with first of all,the possibilities of a study becausebased on my earlier work I could seethat there had been tremendouschanges in the landscape. I could findburied bridges and other indicators in

the landscape that showed me whatmassive erosion had occurred there.

So I went back to Stafford Happand got whatever information he hadat hand. But he said, Well look,there’s a lot more of this informationin the National Archives. He had seento it that a lot of that old informationhad been retrieved and put in variousrepositories.

So in 1973 I wrote a proposal tothe U.S. Geological Survey andbrought Happ into the grant; theyfunded us and we restarted the CoonCreek project in June of 1974. So forthe next five years I spent usuallythree months of every summerworking up there twelve hour days,seven days a week.

ER: What sort of information was inthe archives?

ST: The basic data consisted primarilyof, first of all, borings across thefloodplains. This had been done by anM.A. student at the University ofWisconsin by the name of VincentMcKelvey, later head of the U.S.Geological Survey. Working underthe direction of Happ he would boredown through the modern sediment,which was highly stratified andgenerally brown in color. When he hitthe original soil; that is, the originalprairie soil that was there at the timeof European settlement, it was usuallydark and more homogenous withmuch more organic material in it. Thatcontact was usually quite clear. So hedid all these borings and recorded itall.

Then right behind him came asurveying team. The surveyorsaccording to Happ, were the very best

they could find. Remember, this wasthe Depression and many very goodprofessionals were out of work. So thegovernment could just cruise the IvyLeague schools — Happ, for example,was a Ph.D. out of Columbia — andget the best people because thegovernment could offer living wages.So they had this crack survey crew.The chief surveyor was a man namedWitzgall and he apparently had eyeslike a hawk. He could survey andclose survey lines like no one I have

Volume Seven Number OneJanuary 2000

3


ever seen. I’ve looked at his notes, andthe guy was just beyond belief,particularly when you consider theprimitive equipment that he had to usecompared to what we have now. Heresurveyed all of that area. At thatpoint they had this wonderful data ofthe borings and they had the surveyprofiles on top of that. In many casesthey put monuments in to show wherethe profiles were installed, steel pipesset in concrete on either side of thebasin.

They had two morecrews working, ahydrologic crew thatestablished two streamsediment measuringgauges in Coon Creekto measure the rainfalland to measure sedi-ment coming down thestream. Unfortunatelythat operation onlylasted six years. TheSecond World Warcame up and the workthey were doing herejust obviously had to bedropped.

Before theystopped they also did alot of documentation inthe region. They had acrew that camethrough, includingsome of the people likeHapp and McKelvey,and they made a tremendous numberof photographs. They also did detailedland use studies, which I have. I alsohave aerial photographs made in 1934.I have a collection of time lapsephotographs of that whole regionshowing how the landscape haschanged, particularly since the 1930s.

Some of these government peoplewould knock on doors and ask peopleif they had photographs going backearlier. I have photographs — there

are a couple of them in the USGSpaper — that go back to the turn of thecentury. So you can see landscapefeatures in good condition at the turnof the century; you can see them inhorrible condition in the 1930s; andthen my photographs of the last thirtyor so years show them in greatlyimproved states.

ER: How would you characterize theinformation from the borings and the

surveys and the hydrology and thepictures?

ST: That information has given ustime lapse snapshots of the riparianlandscape. [Riparian means stream-side. Ed.] Thirty years ago we werejust beginning to understand howcomplex the movement of sedimentwas, that it can remain in storage forlong periods of time and then feed out

again. This study has allowed us tolook at that process in detail.

ER: What happens to a soil particlethat is washed off a field?

ST: Say a particle of soil has erodedoff an upland field. Conventionalwisdom, at least among many, wasthat when it erodes it’s on its way tothe Gulf of Mexico. But that particleof soil can be deposited anywhere

from where itbegan. It maybe stoppedanywherebetween thefield and thestream, andeven if it makesit to the streamit can then beredeposited,either in thechannel or onthe floodplainanywhere downthe system.

So thatparticle of soilcan literallytake millions ofyears to get tothe Gulf ofMexico. That’snot to say thatevery particleof soil takes

that long. It’s conceivable that aparticle of soil eroded does go to theGulf of Mexico by the direct route, butthat is a very minor part. Most sedi-ment is going to be redeposited and isgoing to stay in storage for anywherefrom moments to millennia.

ER: What did your fieldwork involve?

ST: First of all, most of those oldprofiles were hard to find. Very few in

Map of Coon Creek basin, Wisconsin, showing researchlocations. More than one hundred transverse valley profileswere surveyed (indicated by lines across streams) in the1930s and again in the 1970s and 1990s.


4


Thirty years ago we were just beginning tounderstand how complex the movement ofsediment was, that it can remain in storagefor long periods of time and then feed out

again.

fact had the permanent markers that Imentioned, the pipes, and of those thathad them, many of the pipes had beendestroyed. They were put alongsideroads for the most part and, of course,with any road widening they would bedestroyed, or a farmer would find onein his field twenty years later, and hewould take his tractor and jerk it out.You don’t know how many times thathappened. So those pipes tended todisappear. Other markers were nails intrees. The profile was usually drawnon an aerial photograph, so thathelped, plus, of course, I had descrip-tions of the location from the surveynotes.

The first big job was finding theprofiles. That’s where Happ was sohelpful because he could remembersome of these things, and in othercases where he couldn’tremember, he was such aconsummate field personthat he could usually findthem from the old fieldnotes. He had an old armymine detector and he’dsniff around these treestrying to hunt for nails.Sometimes it’d be a 10-penny nail which by thattime would be several inches insidethe tree. This man was so patient, if hethought there would be a nail in thetree, he would sit there with this littlehatchet and he would chip awayliterally for hours. There have beendays where I said, We’ve got to get onwith this, and so we’d do somethingelse and we’d come back, it might bethe next day, and there would be a bigpile of chips and a gap cut out of thetree and right in the middle of it wouldbe this rusty nail, but it’d be shinywhere he had hit it with the ax. I don’tknow how many times that happened.

But in many cases we just could

not find many of our marks. Thirtyyears later directions changed becausethe change of magnetic north, andmany of the old compasses were off.So in some cases we had to run trialsurvey lines. In other words, we had tokeep doing surveys until we found thatwe were where our unaffectedtopography matched the old topogra-phy. But surveying those was reallydifficult because many of these surveylines were through almost impassibleswamps. These swamps were oldfloodplains now permanently floodedbecause the stream had built up fromall the sediment in it. Going acrossthem was like... well, let me give thebest example. The first year I went tothe field I had an older student justback from the Vietnam War, a combatveteran. He had spent two years overthere and he told me after the first

week, I’m going to say it far lesscolorfully than he did, but he said, Ididn’t see terrain this bad in Vietnam.

The mosquitoes were terrible andwe were always afraid of encephalitis,but the chiggers got him one day andhe wound up going to the emergencyroom. He was one of several studentsthat had to go to the emergency roomfrom insect bites. Deer flies wereanother problem. they didn’t botherme as much because I took antihista-mines anyway, but if people weresusceptible they swelled like a balloon.

One day it was 112 degrees outthere. Down in these swamps we’rewet up to our waist in water, the rest

of us is wet with sweat, and we’ve gotmosquitoes all over and around us. Idon’t mean to try to portray heroicshere because there were some easyprofiles and some cool, nice days, butsome days and particularly those longranges across the wider bottoms, werejust hell on Earth. I’d come home inthe afternoon and I’d be covered notjust with mud, but with this oldanaerobic muck out of those swampswith sulphur dioxide and all that stuff.Normally I’d come in and my wifewould hose me off out in the drive-way. It’d be dark anyway, so I’d justdrop all my clothes outside, which shewould then further hose off, and thengo inside wrapped in a towel andshower.

I normally tried to take the worstof it, but unfortunately students oftengot it too. It’s unavoidable because we

had to be out therewith the instrumentsand generally therewould be three of usdoing this. That wasjust running the surveylines.Remember, in the

1930s many of theseprofiles were run

across quite open fields. In fact, someof them were even pastures at thattime, so surveying those lines in 1938,’39, ’40 was not so big a problem.When we came back they were notonly grown up into swamps, but somehave grown up into woodlands whereyou can’t see ten feet ahead of you.It’s a real lesson in plant succession.So for 800, 1000, and in one case 2500feet, we had to cut a clear line of sight.Try cutting a half a mile throughwoodland with brush axes. Just cuttingthe line can take two days, and thenyou may find out you’ve got thewrong line. So for some of those older


5


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profiles we spent two weeks. The timerequired is what some people couldn’tunderstand. They would say, Yousurveyed 150 profiles and it took fiveyears?

ER: How do you measure a profile?

ST: You have an optical instrumentwhich is sitting perfectly level. That’syour level line. So you look along itand someone walks along a line with avertical rod demarked to 0.01 feet.You start from one side of the streamchannel or valley, and as you go out anumber of feet, you place this measur-ing rod down on the ground. Theperson reading the instrument knowshow high the level is from earliermarks, so the reading on the level rodshows how much lower that point ofground is than the level. From that youcan get the elevation of the ground atthat point.

In some of those profiles we hadhundreds of measurements; every timewe set the rod down we had a mea-surement. If it’s relatively featurelesstopography like a plain, we might takereadings at every fifty feet; but ifwe’re in a complex valley or streamchannel we might take readings atfractions of feet.

ER: First you had to find the rightline.

ST: Right. Once we have found theline and cleared a line of sight, wethen resurvey along that marked line.We hope to be directly on top ofwhere they were fifty or sixty yearsago. The new survey shows what haschanged in that time.

At the downstream end of thebasin it would usually show

accretional material. We’d be standinganywhere from one to three feethigher than they were, maybe in somecases more than that. In some of thetributaries and middle valley, thestream channels may be two or threetimes as large as they used to be; inother words, channel erosion hadtaken place. In that case the stream isremoving soil. Usually it’s a mixture,in some places the stream has addedmaterial, in other places it’s lostmaterial. This survey gives us aninsight as to process. By looking atthese cross sections of the landscapeover time, we can deduce the pro-cesses that occur.

ER: What do you mean by equilib-rium in reference to soil erosion?

ST: Well, the general concept, even inthe science up to the early or midseventies was that stream sedimentyields were indicators of uplanderosion. The 50-cent word here isdenudation, the stripping away of theland; lowering of the land is anotherterm that’s sometimes used.

Several of us showed in the midseventies that was not necessarily thecase: sediment could either be storedover long periods, thus reducing theamount of material going out, or

conversely that material can come outof storage, increasing downstreamsediment yield.

ER: How does soil come out ofstorage?

ST: Normally it comes out fromchannel erosion. That can either bevertical cutting or horizontal cutting ora combination of both. We find mostlyhorizontal cutting: a stream is mean-dering across the floodplain cuttingaway material from one bank but it’snot putting as much back on the otherside. So over a period of time therecan be a significant loss of sedimentalong the stream channel.

Another thing we didn’t realizeuntil fairly recently is how manyplaces within a stream system that thiscould occur. Within the stream systemthere can be reaches that are losingsediment, there can be reaches that aregaining sediment, and figuring out thebalance can be very complex. There isprobably some sort of system to it, butwe don’t know fully what that systemis. We won’t know until we see thesesorts of things described more fully,and the only way to describe them isto get into the stream and measurethem for a long period of time.ER: The map of the site indicates you


6


There is an inexorable movement of sedimentThere is an inexorable movement of sedimentThere is an inexorable movement of sedimentThere is an inexorable movement of sedimentThere is an inexorable movement of sedimentdownstream, and it's clear it moves in fits anddownstream, and it's clear it moves in fits anddownstream, and it's clear it moves in fits anddownstream, and it's clear it moves in fits anddownstream, and it's clear it moves in fits and

starts.starts.starts.starts.starts.

have a large sample.

ST: It is. And since then I’ve addedmore profiles because I knew thatthere would be attrition of thesefeatures over the following years. So Iadded quite a few, particularly in areaswhere I thought the stream wasrelatively dynamic. For the middleregion of the basin, in particular, Iadded a lot of measurements becausethere’s so much variance there that Iknew we needed a larger sample. Iadded at least fifty new profiles andsure enough when I went back Icouldn’t find many of the profiles.That happens for many reasons.

ER: How would you characterize theresults of your survey?

ST: Well, there is an inexorablemovement of sedimentdownstream, of course,and it’s clear that it movesin fits and starts. Eventu-ally the stuff’s going towork its way downstreamand perhaps out of thebasin, but that may take, as I saidearlier, millennia. In other words therewere huge amounts of sedimentproduced by European-style agricul-ture and if you came back 1,000 yearsfrom now, maybe 2,000, there wouldstill be a lot of that sediment in thatbasin.

ER: How does that compare with thenatural condition?

ST: Well, certainly streams haveundergone changes of this magnitudeunder natural conditions when therehave been strong climatic changes.The presence of stream terraces theretells you that. A stream terrace is anold floodplain, a relict floodplain, andany time you see a terrace above the

present stream you know that thestream system was highly disturbed atone time. So yes, these sorts ofchanges can occur without humanintervention during strong environ-mental changes.

ER: Fire, earthquake, flood.

ST: Well, generally a fire won’t do it,or even prolonged fire won’t in mostareas. It has to be really a strongclimatic change of some kind. Fire ofcourse makes a huge difference insome California basins, but it wouldnever be of that magnitude here. Yes,tectonic changes can set these thingsoff too, you bet.

ER: But normally Coon Creekwouldn't have all this sedimentmoving around.

ST: That's right. Generally in thisregion streams at the time of Europeansettlement were quite stable. There areany number of observations of peoplestanding by streams and being able tocount the number of trout — brooktrout by the way — and being able todescribe bottom formations. I have theaccount written by a young Lieutenantin the Corps of Engineers namedRobert E. Lee, who was coming up theMississippi on a steamboat and hecould observe formations on thebottom of the river from the steam-boat. If you know the MississippiRiver anywhere now, to imagine thatit seems beyond belief, but the upperMississippi was fairly clear appar-ently. At least the tributaries feeding it

were clear.

ER: I’ve seen it on the lower reachesand it’s anything but clear.

ST: Yes. It’s anything but clear nowalmost anywhere. But again, I’m justtrying to tell you what it was like thenat the time of European settlement.

ER: When did serious erosion start inyour study area?

ST: The settlers moved into the areaand by roughly the turn of the centurythey had all the land taken up. By1900 the extent of agriculture in thedrainage was as great as it’s everbeen, but very little erosion hadhappened. The land had enoughnatural resilience to buffer manychanges. The soil was originally quite

fertile and deep, it had ahigh infiltration capacity anda lot of organic material. Sothese people came in andcultivated the soil and verylittle happened. But aftersome period of time you

reach the end of the rope, and that timehappened sometime after the turn ofthe century. By that time, number one,most of the land was in agriculture andmuch of it had been cultivated forforty or fifty years. So those great soilswith all that organic material hadbegun to deteriorate from prolongeduse. Additionally, they had a lot ofcattle on the uplands that were com-pacting the soils, again reducing thecapacity of the soil to infiltrate water.

So around the turn of the centurythe rates of erosion and the rates ofwater flowing off the land startedreaching noticeable proportions. Itwas a threshold situation where youpush a system to a point and it breakssuddenly. That period happenedshortly after the turn of the century.


7


Generally it wasidentified with the FirstWorld War, but that inpart is a coincidence,although during theFirst World Warfarmers pushed the landas hard as they could.

A Mr. Martiny hadbeen living inChaseburg, Wisconsinsince the place wassettled. In 1903 he feltconfident in building ahouse on a terrace just afew feet above thecreek.

Well, in 1907 thebiggest flood on recordcame through and itwas three feet to fourfeet above the founda-tion of the house. Theywere shocked by this. Italked to his son —when I first arrived inthe area many of theseold timers were stillaround — and theywere shocked by thisflood.

So they jacked thehouse up. They said,Surely it’ll never happen again, sowe’ll just jack the house up four feet,put more rock under it, and we mustbe above any flood that’s ever going tohappen.

Well, you look at the foundationnow and it’s totally buried. There’s nosign of it, except a water pipe thatsticks out. Mr Martiny’s son, who wasthen mayor of Chaseburg (1976-77),took us down to the site, showed usthe water pipe, and he said, dig here.Sure enough, a couple days later weget down to the rock. We hit rock atabout four feet but we kept diggingand then we could see the old soil onwhich the house was built.

So as late as 1903 Mr. Martinyfelt perfectly confident in building hishouse there. That house had to beabandoned in the early 1920s; and bythe time we came there in 1977 theplace was buried four feet down. Imention all that just to show you howfast this happened. Once the soilerosion started it was just gangbusters.They didn’t know what was happen-ing to them.

Another example on theWhitewater River is the village ofBeaver, Minnesota. These settlers hadcome from New England as a groupand had built a beautiful little New

England village complete with acommons out there; and the samething happened to them. About 1910-1915 floods started increasing, andthey were in a more vulnerableposition on a somewhat lower terrace.I have a picture showing Beaver in1880 in which you see the village withthe commons and the churches. I haveanother picture made in 1938, andthere’s one house left. So it went froma flourishing village in 1890 to oneremaining house in 1938, and then by1975 when I first visited the place, itwas just another wilderness. This placehad gone from wilderness to wilder-

Aerial photographs of a selected region of Coon Creek basin. Picture on right from1934 shows rectangular fields and gullies across fields from overland flow ofwater. Picture on left of the same area in 1967 planted in contour strips to reducesoil eroision. Images courtesy of S. Trimble


8


ness in 125 years.

ER: How long does it take for soils tostabilize?

ST: Soil recovery doesn’t happenimmediately either, there is a lagperiod. You may treat a particular fieldand do everything you can to it andyou would greatly reduce erosion inthe short run. Youwouldn’t elimi-nate it but youcould certainlyreduce it. Overtime the effective-ness of continuedsoil conservationmeasures becomegreater, and evenmore importantly,the movement ofwater off that fieldis improved. Thefirst year thecondition of thesoil is essentiallywhat it wasbefore, so it’sgoing to take timefor that soil toimprove. It’s gotto get moreorganic material,it’s got to improvestructure, and that may take a decadeor decades.

ER: Was the Dust Bowl era the lowpoint for this watershed?

ST: Yes. Much of American agricul-ture tended to be fairly exploitive, andI don’t want to make too much of thatbecause people in this case didn’tmean to exploit it. There were farmersparticularly in the Southeast, that usedland like they would a wagon: you use

it, wear it out and then buy a new one.But these people, Germans and

Scandinavians, were intelligent,educated people who generally had agood land ethic. They had never orrarely owned land in the Old Countrybut they came here with the idea thatland ownership was a big deal, andthey certainly did not intend to destroythis land. They did though, because

they simply did not have the technol-ogy to deal with it. And the technol-ogy had not been developed in partbecause there had never been ademand for it, again because of cheapland. You use it up and move on. Theterm “inexhaustible soil” appeared inthat era.

These Germans and Scandina-vians came over here and used thebest methods they knew. In the OldCountry, particularly in Sweden butalso in Germany, those methods hadworked just fine because the rainfall

intensities and amounts in Europe areso much less. What they could havedone in the Old Country with impunityfor centuries, wrought disaster withinhalf a century in this environment.Their techniques simply were notadequate to the situation.

These were people who for themost part were doing the very bestthey could. Now I’m sure in the minds

of many of themor some of themmaybe was theidea, Well, if itfolds up here wecan move overto Nebraska orother pointswest. But I don’tthink manypeople saw itthat way. Theyhad theircommunitiesand they had nointention for themost part, ofselling andmoving out, aswas often thecase farthersouth and in theeast. I say thatbecause myearlier work was

in areas where people pretty muchdestroyed the soil and then when theycould, moved.

ER: When did soil conservation getstarted in this country?

ST: We generally had not addressedsoil erosion in this country in anyorganized way before the 1930s. Atthat time it was being addressed by thesoil conservation movement in thiscountry which was very strong. It was

Running survey lines in the lower reaches of Coon Creek, August 1992.


9


headed by H. H. Bennett who laterwas head of the Soil ConservationService. Bennett was a North Carolinafarm boy who became a soil scientist,and he was an evangelist for soilconservation. He went around thecountry making speeches spreadingthe word. To him and his ilk we owe alot because they in fact turned thingsaround in the 1930s including the DustBowl. I don’t know if you’ve seenpictures of it but in the 1930s therewere clouds not once but many timesthat covered square miles. Livestockwould be asphyxiated; even people onoccasion. These dust clouds werecarried to the East Coast where theywould literally darken the sky.

ER: What did the farmers do to holdback the soil?

ST: Well the big things they did thenwere practices like contour plowing,contour strip cropping, and greatlyimproved rotations. The old Europeanthree-year rotation was one year ofcorn, one year of oats, and one year ofhay, then you’re back to corn. But inthe Upper Midwest you actually needabout three years of hay, and if you dothat you can make the soil more orless recover. One year of hay isn’tgoing to do that, and they didn’t knowthat, but later on they did. There are awhole host of treatments to reduceerosion. That’s what we might think ofas first generation soil conservationtechniques. Now we’re into minimumtill, no till, and so forth, which in arelative sense are as important as thoseearlier techniques. In other words, theimprovement the new methodsrepresent is almost as great as theimprovements they got by going fromthe old cropping up and down hill tocontour strip cropping and so forth.

ER: How do you generalize fromthese results in Coon Creek to other

watersheds, different climates, differ-ent soils?ST: With great care. But I’d say firstof all that Coon Creek, and even theupper Mississippi River is not the onlyplace I’ve seen. There is scatteredevidence from throughout the East thatthe model of Coon Creek is notinappropriate. The chronology, theabsolute numbers may be quitedifferent, but the general trend issimilar.

In the Southern Piedmont somesimilar things occurred. What wasdifferent there though is that much ofthat land simply reverted to forest.Rather than improvement of cropping,it was a great reduction of croppingand the lands reverted to forest or insome cases pasture, which was a farbetter land use. I don’t mean todownplay soil conservation measures,they were important. But the change inthe Coon Creek area was not changeof land use, it’s change of landtreatment. They’re still growing corn,they’re still growing soybeans, they’restill growing wheat and in almost thesame acreage, or close to it. It’s justthat they do it far differently.

The only generalization I wouldmake is that I think my work onlyaddresses in general the humid easternUnited States. However, I’m willing togo on record here saying that I thinkthere has been great improvement inalmost all regions of the United States.Not to say recovery, and probably notto the extent of the recovery that wesee in Coon Creek. Soil erosionremains a problem, but I think it’s nota crisis no matter how you define it.

Literature Cited:

1 Decreased Rates of AlluvialSediment Storage in the Coon CreekBasin, Wisconsin. SW Trimble 1999Science:285:1244-1246

EmerEmerEmerEmerEmerging Marineging Marineging Marineging Marineging MarineDiseasesDiseasesDiseasesDiseasesDiseases

Introduction:

In a recent article in Sciencemagazine Professor Drew Harvell andother biologists present an overviewof recent trends in marine ecology.Major groups of marine animals havesuffered disease outbreaks and massdie offs1. Reports of epidemics incorals and some marine mammalshave increased. A dramatic increase incoral bleaching around the worldoccurred in 1997-98 coinciding withincreased sea surface temperaturesdue to that year’s El Niño.

It is thought that environmentalstresses may compromise animals’resistance to disease and increase thefrequency of opportunistic diseases.Human-caused stresses includepollution and increasing sea surfacetemperatures as a result of globalwarming.

Disease outbreaks can occurwhen a disease causing organismchanges its host. For example, theHIV retrovirus that causes AIDS inhumans probably originated in apes,and flu often comes to us from birds.Disease can also move into newgeographic regions either when thedisease organism changes or theenvironment changes. Malaria forexample is expected to move intomore temperate regions in the futureas global climate warms. Thesepatterns of disease movement and hostshifting also occur in the oceans,however marine scientists have onlyrecently begun to study them system-atically. We spoke with ProfessorHarvell about marine diseases andwhat we need to do to understand


10


them better.

ER: Professor Harvell, what is yourtraining?

DH: I’ve been a professor at CornellUniversity since 1986. Before that Ireceived a Ph.D. from the Universityof Washington followed bypostdoctoral training at Friday HarborLabs in Washington and at WoodsHole Oceanographic Institute. Mygraduate work focused on the evolu-tionary ecology of marine invertebratedefenses against predators, workinglargely in temperate oceans.

After moving to Cornell I startedtropical work with defenses of gorgo-nian soft corals. I became interested inthis study system because soft coralsare well known for having interestingchemical defenses. I wanted to tietogether work that was being donewith plants and animals. Plant ecolo-gists were focussing on chemicaldefense and scientists working withinducible defenses of animals werefocussing onmorphologicaldefense. Sincecorals are colonialanimals and arelike plants inseveral respects Ithought this would be a good studysystem for evaluating the role ofsecondary chemicals in defense ofcolonial invertebrates.

For many years we worked on thepredator deterrent aspects of second-ary compounds, such as the chlori-nated briaranes and the hydroquinonesof several species of Caribbeangorgonian and that’s the project thatled me into the disease work. Througha collaboration with Bill Fenical andPaul Jensen at Scripps, and later KihoKim at Cornell, we surveyed thecommon Caribbean gorgonians forbiological activity and detected

significant anti-bacterial and anti-fungal activity in extracts of many ofthem. So to understand the puzzle ofthis diversity of interesting com-pounds, it became clear to me that wewere going to have to understand therole of pathogens.

We started working on a fungaldisease outbreak in sea fans. Most ofthe diseases of corals have not beenidentified; that is, we don’t know thecausative microbial organism. And thewonderful thing, at least from ourperspective, about the sea fan patho-gen is that it was a fungus that wasidentified by Garriet Smith and DaveGeisler, so we knew the causativeagent. It could be cultured in the lab,and that gave us the ability to assaythe chemistry of the sea fans againstthe living pathogen. As far as I knowthat’s never been done for any othercoral diseases.

ER: How often does a marine diseaseappear because it crosses to a newhost?

DH: My sense is that we don’t haveenough data to evaluate that very well.We gave a couple of examples in theScience paper. One example is thefungus that’s affecting our sea fan.We’re studying a sea fan that’simpacted by a fungal pathogen,Aspergillis sydowii. Prior to thisepidemic in the sea fans, this fungushad never been reported as a pathogenin the ocean. However a closelyrelated species, Aspergillis fumigatushas long been known as a humanpathogen and indeed a killer of cancerpatients.

The simplest hypothesis toexplain the outbreak of disease in thesea fan corals is that the Aspergillissydowii fungus was washed in fromterrestrial soil where it’s known tooccur naturally and, for whateverreason, the environment changed orthe genetics of sea fan changed andthe sea fan became a suitable host.That’s one possible example of a hostshift, in this case changing fromterrestrial to a marine environment.

One of the problems with thishypothesis of a new introductionthough, is that we know Aspergillissydowii has been in the ocean before.It’s been recorded from marinesediments. So even with this casewhich seems to some clear cut, we’restruggling to understand more pre-cisely the origin of this outbreak.

ER: What is the extent of the disease?

DH: It’s Caribbean wide. IvanNagelkerken , who’s been working in

Curaçao, first docu-mented that sea fansthroughout the Carib-bean were affected bythis epizootic. [Anepizoitic is an epi-demic in animals. Ed]Following that, Kiho

Kim (then a postdoc) and I initiatedmonitoring studies in Florida tounderstand the epidemiology of thedisease. So we’re asking questionslike, Were small individuals infectedor large individuals? What’s theprobability of the sea fan dying onceit’s infected? Kiho is trying to corre-late intensity of infection with envi-ronmental variables, such as turbidityof water, nitrogen level and chloro-phyll A.

At least at the sites where wehave permanent transects, the diseasehas had a significant impact on the

...many of these epidemics are like lightning strikes: they hitquickly, unexpectedly, they run through a population and then

they're gone.


11


Many of these marine organisms have chemicals that slow orinhibit bacterial or fungal or viral growth, as well as having

effects on predators or competitors.

populations. At some sites as many as20 percent of the fans have died.There were probably similar impactsthroughout the Caribbean although wedon’t have the data to know.

ER: Can you keep sea fans going, orat least samples of them going in thelab?

DH: Its possible tomaintain them in thelab, but it is not ourcurrent focus. All thesea fan work we do iseither in the field orin the lab directlyadjacent to the field.To work with host resistance it’simportant to have healthy hosts. Wedon’t want to be in a situation whereour hosts are stressed physiologically,so we’ve developed methods ofrunning experiments in the field sothat we’re sure we’re not adding labartifacts.

The fungus grows well in petridishes, allowing us to work comfort-ably with one half of the associationhere in New York and then the otherpart of the work we conduct in thefield.

ER: What about this idea of chemicaldefenses?

DH: There is a rich literature onnatural products chemistry of marineinvertebrates. In fact a large propor-tion of the so-called hits that theNational Cancer Institute finds forpotential anti-cancer drugs is frommarine organisms. There’s a growthindustry there, just to understand thechemistry and to isolate biologicallyactive compounds. Many of thecompounds that the National CancerInstitute is examining are interestingbecause they disrupt mitosis or haveother biological functions.

The novel chemicals chemists arefinding in marine organisms also havesome important ecological roles innature, and it’s the rich tradition ofnatural products chemistry that hasdriven the growth of chemical ecol-ogy. Many of these organisms havechemicals that slow or inhibit bacterialgrowth, slow or inhibit fungal growth,viral growth, as well as having effects

on predators or competitors. So nowthe real task in my mind is to under-stand what role those compounds playin nature.

Some of the groups of animalsthat have been the prime study targetsof the natural products chemists areorganisms like soft corals or sponges,which are sessile, and they seem tohave a high allocation to chemicaldefense in the same way that plantsdo.

ER: They don’t have the option ofrunning away.

DH: That’s right. Which is a little bitof a tip-off that some of that activity innature has an important defensive role.For example, with the gorgonians —they’re a group of soft corals, andthere about forty species in theCaribbean — we’ve assayed theantibacterial activity of these speciesin collaboration with Bill Fenical andPaul Jensen at Scripps, and found thata fair number of them have some kindof antibacterial activity. As an under-graduate honors thesis, Paul Kim didthe same with antifungal activity on asubset of those gorgonians and wesubmitted the paper this week docu-

menting that a fair number of themhave some sort of antifungal chemis-try.

ER: Are these novel agents?

DH: Yes, in some cases they likelyare. Melissa Wagenaar working in JonClardy’s lab at Cornell has identifiedsome new antifungal components

from our extracts.We haven’t evenstarted in onextracts fromspecies other thanseafans. So therecertainly is bio-medical potential

for some of these chemicals.

ER: Do they attack the bugs in adifferent way than other drugs?

DH: That’s the goal of course: to findnot only new compounds as potentialdrugs but also new mechanisms ofactivity. In the case with the sea fans itwould be useful if we found a novelantifungal agent against Aspergillissydowii because it might have clinicalrelevance against the human pathgoenAspergillis fumigatus.

The reality however, in terms ofthe clinical applications for these newcompounds, is that many of them aretoo toxic to be used directly as drugs,but they can certainly yield importantleads to biomedical researchers.

There is one compound from aCaribbean gorgonian, pseudopteresin,an anti-inflammatory compounddiscovered in Fenical’s lab that’s inclinical trials as an arthritis drug. Infact Estee Lauder working with BillFenical at Scripps developed anantiinflammatory skin care productthat’s based on the extract.

ER: How does environmental changeinfluence diseases in the ocean?


12


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There haven't been many cases where a new pathogenThere haven't been many cases where a new pathogenThere haven't been many cases where a new pathogenThere haven't been many cases where a new pathogenThere haven't been many cases where a new pathogenemerges that's never before been a pathogen. Thereemerges that's never before been a pathogen. Thereemerges that's never before been a pathogen. Thereemerges that's never before been a pathogen. Thereemerges that's never before been a pathogen. Thereare more cases where a pathogen has undergone aare more cases where a pathogen has undergone aare more cases where a pathogen has undergone aare more cases where a pathogen has undergone aare more cases where a pathogen has undergone a

range shift or a host shift.range shift or a host shift.range shift or a host shift.range shift or a host shift.range shift or a host shift.

DH: Certainly a focus on understand-ing how increased temperature affectsdisease is a priority. Alisa Alker aspart of an honors thesis showed within vitro culture experiments that theoptimal temperature for the Aspergillispathogen is at 30 degrees Celsius, nearthe peak of summertime temperaturesin the Keys. Thus we would predictthat warming temperatures would givethe pathogen a growth advantage. Thiskind of experiment is only possible forpathogens that we can maintain inculture. Another challenge is simply todescribe environmental change. I justspent the last hour in the GeologyDepartment here talking with BruceMonger and Jen Whiteis about theirremote sensing project to try to workout a way of describing temperaturechanges that have occurred in theCaribbean over the last ten years toprovide the environmental backdropfor assessing apparent increases indisease and bleaching.

What is striking is the lack ofdisease monitoring data to go with thisenvironmental information. We haveways of getting at the environmentaldata, and now it seems to me anenormous priority to put some diseaseand coral bleachingmonitoring pro-grams in place. Ithink they areforming, but hardlyfast enough to dealwith this issue.

ER: Isn't there a monitoring study inthe Florida Keys?

DH: The Florida Keys is a differentsituation: there have been good coralmonitoring programs there for the lastten years. Jim Porter, Esther Peters,Debby Santavy, Erich Mueller andothers have been running a coraldisease monitoring project, a collabo-

ration between ecologists and microbi-ologists to assess in hundreds of sitesthroughout the Keys how the levels ofcoral disease are increasing anddeclining, waning and waxing.

The other thing that’s innovativeabout work in the Florida Keys is thatthere’s been good environmentalmonitoring in place for the last five toten years also. The Southeast RegionalWater Quality Program monitorstemperature, chlorophyll-A, nutrients,all the relevant water chemistryparameters at hundreds of sitesmonthly throughout the Keys.

Our addition to this is we’reworking with sea fans trying tocorrelate changes in the prevalence ofthe disease - the percentage of indi-viduals that have a disease, and theamount of damage from disease - withthese various water quality parametersthey are measuring. Kiho Kim hasmonitored seafans for three years atnine sites spanning the length of theFlorida Keys, and is now attempting tocorrelate the disease and environmen-tal data.

One strength of our program isthat since we’re only monitoring onespecies we are able to measure

parameters in more detail: we knowhow sick individual sea fans are andhow that varies with fan size and site,and most of the other monitoringprograms measure only whetherthere’s any disease present at a siteand can’t take data from individualcorals, but they’re monitoring diseasesof fifty species.

It’s a hard thing to come up withthe good data to nail down correla-

tions between a disease and changes inthe environment. It seems an obvioushypothesis that disease outbreaks maybe related to declining environmentalconditions, but there are very fewgood data to show that association.The question that I’m asked over andover again is, Are there more new

diseases now? And you can’tanswer that question withouta good historical baseline,which at this point we don’thave for marine diseases.

ER: It seems like commonsense: if you see a lot of

pollution and you see dead corals,there’s a connection.

DH: Yes, but it’s important to havethe right kind of replication to be ableto establish cause and effect. Or in thecase of trying to detect a correlationbetween environmental parametersand the disease, again, there needs tobe enough variation. You need sites


13


These coral reefs (in the Caribbean) are near thenorthern extent of reef growth. They're

experiencing some of the highest summertimetemperatures and some of the lowest of the

wintertime temperatures for the Caribbean, soit's difficult to pick out the causative agents in

some of the declines.

where there’s high levels of thepollutants and a lot of damage fromthe disease, and then a range to siteswith different levels of disease andstressors because there are a lot ofother factors — and realisticallymultiple stressors — that couldcontribute to the mortality associatedwith disease. To tease apart what isthe causative agent of this requiresgood data sets that span large spatialscales and fairly long temporal scales,and that’s missing in most cases.

It’s not enough to say: this seemsto be a polluted site and these coralsare dead. You need somethig morelike five polluted sites and five controlsites to demonstrate that the coralsdied at all the polluted sites and theydid not die at any of thecontrol sites.

ER: You could useKoch’s rules: give thebug to them and see ifthey get sick; take it awayand see if they get better.

DH: There’s been verylittle experimental workwith disease in marine organisms. Tofulfill Koch’s postulate requires threesteps: 1) isolating a micoorganismfrom diseased individuals, 2) estab-lishing it in pure culture and 3)successfully reinoculating healthyhosts and producing disease symp-toms. The failure oftentimes to fulfillKoch’s postulate illustrates theproblem with marine diseases becausemany of the pathogens aren’t easilycultured. It’s an enormous victorywhen even a single pathogen isidentified and Koch’s postulate isfulfilled, and there are only three orfour species of coral diseases forwhich that’s the case, balanced againsta list of about fifteen symptoms whichdistinsguish other coral diseases:

white pox, porites ulcerative whitepox, white band, white plague, oryellow blotch, where the causativeagent is not known and we’re simplyrelying on the symptoms.

ER: It seems like the Florida Keysmay give you the best information.

DH: The problem with the Keys formaking simple conclusions is that it’sa very complex ecosystem. There is asubstantial anthropogenic influencethere, but it’s overlaying an alreadyfairly stressed, variable ecosystem.Those coral reefs are near the northernextent of reef growth. They’re experi-encing some of the highest of sum-mertime temperatures and some of the

lowest of the wintertime temperaturesfor the Caribbean, and so it’s difficultto pick out what are the causativeagents in some of the declines we seefrom that area. For example, there’s alot of fresh water input and in manycases we know the quality of thatwater coming out of the Evergladesand Florida Bay is not always good,but its challenging to pinpoint thisrather than other environmentalchange as a causative agent of coraldecline.

ER: Where are new diseases comingfrom?

DH: There haven’t been many caseswhere a new pathogen emerges that’snever before been a pathogen. It

seems there are more cases where thepathogens that are found have under-gone a range shift or a host shift: fromone organism to another. One exampleof a host shift is that of themorbillivirus of seals and other marinemammals, which is interesting be-cause it’s virtually identical to thecanine distemper virus.Molecular studies suggest there islikely a terrestrial link with somestrains of morbillivirus and scientiststhink the seal morbillivirus originatedin a terrestrial canid. Among the betterstudied bivalve diseases we also seehost shifting. In oysters and clamsthere’s a whole group of Perkinsis thatappear to have host shifted amongvarious bivalve taxa. This host

shifting might be a commonmotif of a new diseaseappearing and is an issue thaturgently needs good quanti-tative data.

ER: One thing that we knowfrom human epidemiology isthat there seems to a mini-mum population size for thehost species to keep the

disease going. Is that an issue inmarine systems?

DH: I think those are starting to besome of the ecologically and evolu-tionarily exciting questions thatecologists can ask about these sys-tems. Certainly it is a vital issue forconservation biologists to understandwhat’s a critical host size for mainte-nance of an epidemic.

There’s been some beautiful workdone by Bryan Grenfell and col-leagues with the seal morbillivirus thatsuggests that the population size of theseals is such that the morbillivirus willeventually always die out. That’s theonly case I know of where there’sbeen that kind of an epidemiologicalanalysis in a marine organism. There


14


may be examples with oyster too. Butfor most natural populations, in thefirst case, we don’t know what thecausative agents are, and so it’s hardto study the epidemiology. In thesecond place, we don’t know enoughabout resistance to understand what’sa viable host and what isn’t. And inthe third case, there just hasn’t beenthe kind of work done in marinesystems to quantitatively study thedynamics of the epidemic. I hope thiswill change because those are criticalquestions.

The sea fan disease has been afairly extended epidemic, and we’vebeen able to study it for several yearsand actuallydevelop a prettygood data baseand a profile ofhow thatepidemic hasaffected itspopulation.

But many of these epidemics arelike lightning strikes: they hit quickly,unexpectedly, they run through apopulation and then they’re gone. Wedocumented one last year in theFlorida Keys at the height of the ElNiño high temperatures in a gorgoniansoft coral, Briareum asbestinum: over60 percent of the individuals werekilled within 3 months and then allsymptoms of the survivors disap-peared. You couldn’t do an epidemio-logical analysis of something that wasso virulent and that ephemeral.

ER: We may need an emergencyresponse plan for ecosystems.

DH: We have talked about needingCenters for Disease Control forenvironmental disease and marinediseases certainly — a critical need isto identify the causative agents fornew outbreaks. This requires the kindof rapid response capability and

instrumentation that we associate withthe CDC for human disease. Both theurchin disease that virtually eradicatedthe dominant urchin from the Carib-bean and the frog viral and fungaldiseases on land underscore thepotential danger that emergentdiseases can pose to biodiversity. It isimportant to have a rapid responsecapability so we can at least identifythe causative micro-organisms asthese outbreaks occur.

That’s where I hope this interviewwill be useful: to help people under-stand that there’s a real need forputting funds into understandingdisease processes in natural ecosys-

tems in the ocean. It’s a wholedifferent ball game in ocean systemsthan on land. We know very littleabout transmission biology of diseasesin the ocean, and yet oceans aretraditionally thought of as being opensystems where water masses freelymix.

In such an open system we wouldpredict that disease propagules couldget readily from one geographicregion to another and spread veryrapidly. And yet, despite the hypoth-esis that disease transmission might bemuch faster and greater in the ocean,there are no quantitative data to assessthe hypothesis. Transmission ofdisease is very well understood interrestrial ecosystems because of theeconomic importance of human andagricultural disease and concernsabout endangered wildlife. Ourunderstanding of the rates of diseasetransmission and the role of hostresistance is far behind for marineorganisms.

There are some classic cases likechestnut blight and Dutch elm diseasethat spread and caused enormousmortality over short periods andchanged the face of terrestrial forestedecosystems within ten or twenty years.We don’t have examples like thatfrom the ocean, and I would guess thatis because we’ve missed many ofthem, they’ve probably happened andwere never recorded.

We saw the example of theDiadema antillarum, which is a seaurchin in the Caribbean that wasvirtually eradicated by a mid-eightiesepidemic. That was a spectacularepidemic that was well recorded, and

scientists were able towatch the urchins fallapart throughout anisland within a spaceof several days, andthen a week later it hitthe next island. So

there did seem to be a waterborneagent that spread Caribbean wide inthat case. As far as I know, that’s theonly situation where there were anyestimates made of transmission rates.

ER: These problems cross a lot aacademic boundaries.

DH: That’s why we wrote the Sciencepaper, because evaluating the causesof recent increased reports of diseasesin the ocean is a complex topic and itneeded to be a whole paper to describethe magnitude of the problem, and thatit wasn’t just affecting corals, itwasn’t just affecting seals, and not justoysters, but organisms in manyregions were affected.

When we have processes that wedon’t understand causing major shiftsin the composition of communities inthe ocean, I think it’s a cause of someconcern. The impacts of disease forlong-lived organisms could be farreaching. In the case of corals, some

One example of a host shift: the morbillivirus of seals is virtuallyOne example of a host shift: the morbillivirus of seals is virtuallyOne example of a host shift: the morbillivirus of seals is virtuallyOne example of a host shift: the morbillivirus of seals is virtuallyOne example of a host shift: the morbillivirus of seals is virtuallyidentical to the canine distemper virus... scientists think the sealidentical to the canine distemper virus... scientists think the sealidentical to the canine distemper virus... scientists think the sealidentical to the canine distemper virus... scientists think the sealidentical to the canine distemper virus... scientists think the sealmorbillivirus originated in a terrestrial canid (dog).morbillivirus originated in a terrestrial canid (dog).morbillivirus originated in a terrestrial canid (dog).morbillivirus originated in a terrestrial canid (dog).morbillivirus originated in a terrestrial canid (dog).


15


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Blood Lead Levels in American Children:Blood Lead Levels in American Children:Blood Lead Levels in American Children:Blood Lead Levels in American Children:Blood Lead Levels in American Children:Bruce LanphearWhat’s Causing the Extinction of TopWhat’s Causing the Extinction of TopWhat’s Causing the Extinction of TopWhat’s Causing the Extinction of TopWhat’s Causing the Extinction of TopPredators? Predators? Predators? Predators? Predators? Joshua Ginsberg and RosieWoodroffe

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Are Fish Farms Sustainable?Are Fish Farms Sustainable?Are Fish Farms Sustainable?Are Fish Farms Sustainable?Are Fish Farms Sustainable?Rebecca GoldburgHow Do Tropical Forests Recover fromHow Do Tropical Forests Recover fromHow Do Tropical Forests Recover fromHow Do Tropical Forests Recover fromHow Do Tropical Forests Recover fromLogging? Logging? Logging? Logging? Logging? Preston Aldrich

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A New Threat to the Monarch ButterflyA New Threat to the Monarch ButterflyA New Threat to the Monarch ButterflyA New Threat to the Monarch ButterflyA New Threat to the Monarch ButterflyMigration: Migration: Migration: Migration: Migration: O.R. TaylorTracking Migratory Birds in the Neotropics:Tracking Migratory Birds in the Neotropics:Tracking Migratory Birds in the Neotropics:Tracking Migratory Birds in the Neotropics:Tracking Migratory Birds in the Neotropics:Peter Marra

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Using Tree Rings to Reconstruct ClimateUsing Tree Rings to Reconstruct ClimateUsing Tree Rings to Reconstruct ClimateUsing Tree Rings to Reconstruct ClimateUsing Tree Rings to Reconstruct ClimateHistory: History: History: History: History: David StahleMeasuring Greenland’s Ice Sheet:Measuring Greenland’s Ice Sheet:Measuring Greenland’s Ice Sheet:Measuring Greenland’s Ice Sheet:Measuring Greenland’s Ice Sheet: William KrabillPrairie Chicken Conservation: Prairie Chicken Conservation: Prairie Chicken Conservation: Prairie Chicken Conservation: Prairie Chicken Conservation: Jeffrey Brawn

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The Long Reach of El Niño:The Long Reach of El Niño:The Long Reach of El Niño:The Long Reach of El Niño:The Long Reach of El Niño:Michael McPhadenEffects of Increased Atmospheric CarbonEffects of Increased Atmospheric CarbonEffects of Increased Atmospheric CarbonEffects of Increased Atmospheric CarbonEffects of Increased Atmospheric CarbonDioxide on Coral Reefs: Dioxide on Coral Reefs: Dioxide on Coral Reefs: Dioxide on Coral Reefs: Dioxide on Coral Reefs: Joan KleypasBenefits of Marine Reserves: Benefits of Marine Reserves: Benefits of Marine Reserves: Benefits of Marine Reserves: Benefits of Marine Reserves: Craig Dahlgren

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Does One Exotic Pest Deserve Another?Does One Exotic Pest Deserve Another?Does One Exotic Pest Deserve Another?Does One Exotic Pest Deserve Another?Does One Exotic Pest Deserve Another?Robert OhmartTrading Air Pollution Permits: Trading Air Pollution Permits: Trading Air Pollution Permits: Trading Air Pollution Permits: Trading Air Pollution Permits: Jay CogginsFire Hits the Tropical Forestry Initiative: Fire Hits the Tropical Forestry Initiative: Fire Hits the Tropical Forestry Initiative: Fire Hits the Tropical Forestry Initiative: Fire Hits the Tropical Forestry Initiative: CarlLeopold

OctoberOctoberOctoberOctoberOctober

Drug Resistant Tuberculosis: Drug Resistant Tuberculosis: Drug Resistant Tuberculosis: Drug Resistant Tuberculosis: Drug Resistant Tuberculosis: Jeffrey StarkeForest Responses to Greenhouse Gases:Forest Responses to Greenhouse Gases:Forest Responses to Greenhouse Gases:Forest Responses to Greenhouse Gases:Forest Responses to Greenhouse Gases:Evan DeLuciaJobs Versus the Environment?Jobs Versus the Environment?Jobs Versus the Environment?Jobs Versus the Environment?Jobs Versus the Environment?Eban Goodstein

NovemberNovemberNovemberNovemberNovember

Does It Matter What We Do to the World’sDoes It Matter What We Do to the World’sDoes It Matter What We Do to the World’sDoes It Matter What We Do to the World’sDoes It Matter What We Do to the World’sOceans?Oceans?Oceans?Oceans?Oceans?An Address to the Ecological Society ofAn Address to the Ecological Society ofAn Address to the Ecological Society ofAn Address to the Ecological Society ofAn Address to the Ecological Society ofAmerica: America: America: America: America: Sylvia Earle

DecemberDecemberDecemberDecemberDecember

Fire History of Southern California:Fire History of Southern California:Fire History of Southern California:Fire History of Southern California:Fire History of Southern California:Jon KeeleySeven Steps to a Healthier Planet: Seven Steps to a Healthier Planet: Seven Steps to a Healthier Planet: Seven Steps to a Healthier Planet: Seven Steps to a Healthier Planet: John RyanBenefits of Marine Reserves Revisited:Benefits of Marine Reserves Revisited:Benefits of Marine Reserves Revisited:Benefits of Marine Reserves Revisited:Benefits of Marine Reserves Revisited: Alan Hastings


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NEXT MONTH

GREEN URBANISM:Timothy Beatley

OZONE LOSS ANDINCREASED UV

RADIATIONWilliam Randel

of these hard corals may be 700-year-old individuals and they are dyingover a space of a month or two. I don’twant to over inflate the urgency; as anecologist I also know that disease haslikely long been an important andnatural agent structuring marinecommunities. Our problem today isseparating natural and human facili-tated impacts of diseases. Clearlyscientists have agreed it’s an importantissue. That’s why it was important togather thirteen scientists from differ-ent disciplines together to write aconsensus statement to identify whichparts of this problem we agree on andthat disease is having large negativeimpacts on biodiversity. The worri-some part is that we don’t understandthe ecological and evolutionarydisease processes very well, and ontop of that it’s possible that theenvironment is changing throughincreased seasurface temperatures.

In my view part of the solution isto be sure that at least starting now wehave an historical baseline for pro-cesses that are important in thesemarine communities and try todevelop the right kind of monitoring

studies so that twenty years from nowwe can answer the questions aboutwhether the intensity of disease ischanging.

Literature Cited:

1 Emerging Marine Diseases -Climate Links and AnthropogenicFactors. CD Harvell et al 1999Science 285:1505-1510


Documents

A Monthly Newsletter of Environmental Science and Policy · the Coon Creek basin for an intensive study of soil erosion that involved surveys throughout the basin, land use studies,