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Advances in Conservation Agriculture Volume 2: Practice and Benefits

Edited by Professor Amir Kassam University of Reading, UK and Moderator, Global Conservation Agriculture Community of Practice (CA-COP), FAO, Rome, Italy

BURLEIGH DODDS SERIES IN AGRICULTURAL SCIENCE

E-CHAPTER FROM THIS BOOK

© Burleigh Dodds Science Publishing Limited, 2020. All rights reserved.

Biodiversity management practices and benefits in Conservation Agriculture systems 15

5 Case study: biodiversity management practices and bene its in CA systems in South-West Manitoba (Canada)

This section is written by Scott Day. In 1989 I began farming with myfamily and also working as a Provincial Government Extension AgronomistandthenaResearchFarmManagerinSouthwestManitoba.Myworktookmethroughout the Southwest corner of Manitoba and beyond to other parts of the World. In 2012, I left the Manitoba Government to help start afarmland investment and management company based in the USA. Weinvest in farmland across the US with a focus on soil conservation in oursubsequentmanagementoftheproperties.OurcompanyalsoinvestsinnewAgTechnology.However,Ineverstopped farming and I continue to farm with my family to this day. I spend the wintermonthsinSiliconValleyworkingoutofourheadoffice there and I spend the summer months back in Manitoba near the family farm during the growing and harvest season.

Our farm is located approximately in the middle of Southwest region of Manitoba:25kmsNorthof theNorthDakotaborderandabout60kmsEastfrom the Saskatchewan border. Our home farming region is located near the exact geographical centre of NorthAmerica,making this region one ofthe farthest on the continent from the moderating effects of any ocean. As a result, it is also a region that sees some of the most extreme weather. In our farming

Biodiversity management practices and benefits in Conservation Agriculture systems16


regionwecaneasilysee−40Candplus40C ina6-monthperiod.Wecansee40Ctemperaturechangesinafewdaysduringthespringandfall.Itcanfreezeonedayandbeplus30Cthenextday.Ournumber1causeofcropfailureisdrought,andournumber2isflooding,ournumber3istoomuchheatand our number 4 is too much cold. With these incredible variations it is hard tocompareoneyeartothenextandsomewhat impossibletodefinewhatanormal year represents.

Withour farm location in theEasternCanadianPrairieswegrowawidevariety of crops depending on weather, agronomy and market conditions. Over theyearsourfarmhasproducedsunflowers,flax,peas,drybeans,soybeans,barley, winter wheat, spring wheat, and all types of canola and rapeseed. Other crops that are common in my region now include grain corn, hemp, grass seed,alfalfa,lentils,oats,andrye.Themaincropsonourfarmgoingintothe2019 planting season are canola, hard red spring (HRS) wheat,malt barley,soybeans and dry beans. Our farm has seen virtually no widespread tillage for almost 30 years. All crops are seeded and fertilized in one pass with ammonia, with the other nutrients being applied as dry products with our air seeder. Theseedisplacedinaverynarrowbandgenerallyat2.5cmindepth,whilethe fertilizer is applied about 4 cm to the side and 4 cm below the seed in a separatenarrowband(generally1.25cmwide).MostseedingisnowdoneinasimilarfashiononourNorthernPlains.

Early in my career both as a farmer and as an Extension Agronomist, I was very fortunate to have been mentored by some of the pioneering no-till farmersinWesternCanadaandtheNorthernUSA.TheseincrediblevisionariesencouragedmetogetinvolvedintheManitoba-NorthDakotaNo-TillFarmersAssociationalongwithvariousotherConservationAgriculture initiatives.TheMan-DakNo-Tillgroupwasoneofthefirstformedintheearly1980sandgrewrapidlyinmembersandinfluenceintheearly1990s.Itwasagreatexperienceand one I feel incredibly fortunate to have been involved with at the time. I got tobeapartof thetremendouschangeinagricultureontheNorthernPlainswhere, in a relatively short period of time, most farmland switched from being tilled tono longerbeing tilled. Inmy school years upuntil the late1980’s Iremember when strong spring winds would often whip up dust storms by blowingtopsoilfrom100’sofkmaway,almostblockingoutthesunattimes.Sincetheadventofno-tillinthe1990’sIhaveneverseenanotheroneoftheselarge dust storms in my region.

Trying to evaluate the changes or the impact of no-till on biodiversityis difficult in such a variable environment as the region inwhich I farm, butI will share some observations from my almost 30 years of working with and promotingCAsystemsandpractices inmyregionofCentralNorthAmerica.However,beforeIbegin,IwanttoshareasectionfromtheFAOBook‘TheStateoftheWorld’sBiodiversityforFoodandAgriculture’(FAO,2019,p87):



‘Links between biodiversity, biodiversity loss and disease risk:An increasing number of emerging infectious diseases in humans, animals and

plants have been reported over recent decades (Anderson et al., 2004; Fisher et al., 2012; Jones et al., 2008). This has been linked to rapid habitat changes caused by urbanization and agriculture intensification (Hassell et al., 2017). Empirical studies show that high levels of biodiversity are associated with high levels of pathogen diversity (Morand and Lajaunie, 2017). However, increases in epidemics and the risk of disease emergence are associated with decreased biodiversity (ibid.), as deforestation and agricultural intensification increase contacts between wildlife, domestic animals and humans, favouring the spread of zoonotic diseases (Keesing et al., 2010). Empirical studies have also shown that species-rich host communities contribute to reducing the transmission of infectious diseases, a phenomenon known as the “dilution effect”. The effect has been observed in studies on several vector-borne and zoonotic diseases. A meta-analysis of 90 studies on various diseases that affect humans, wildlife, livestock or plants concluded that they provide broad support for a negative effect of diversity on disease transmission (Johnson et al., 2015). The magnitude of the effect, however, appears to be related to the structure of species communities and not only to species diversity per se (Civitello et al., 2015). Similar effects operate at the intraspecies (genetic) level. Species that have high genetic diversity may sustain a high diversity of pathogens, but with each pathogen showing low transmission and rarely causing an epidemic. In contrast, while species that have low genetic diversity may sustain fewer pathogens, these pathogens may have high transmissibility and the potential to cause dramatic epidemics (Heesterbeek et al., 2015; Karvonen et al., 2016; King and Lively, 2012).’

One of the issues that I remember clearly was the emergence of orange blossom wheatmidgeasasignificantprobleminspringwheatduringthemid-1990’sacross theNorthernPlains.This tiny, fragilemidgehasnomouthandsimplyexiststolayeggsonthefloweringheadsofcerealcrops–mainlyspringwheat.Thesemidgeeggshatch into larvae that feedon thegrowingkernels in thewheatheadcausingyieldreductionsandqualityproblems.Beforethewheatheads fully mature the well-fed larvae drop to the ground where they remain over winter, sometimes even for years, before they pupate in the summer into thetinymidgesthatflyupintothewheatcanopyagaintolaytheireggsandstart the cycle over again.

Many farmers and some scientists attributed its increased presence to the rise of no-till system at that time as they thought the undisturbed soil was a perfectharborforthemidgelarvae/eggs.Thoughthatwasjustananecdotalobservation, this assumed connection did gain considerable acceptance at the time. However, farmers spraying indiscriminately, regardless of the midge number threshold, seemed to need to spray the following year regardless of their tillage practice. However, farmers that did not spray indiscriminately oftendid not need to spray the following year.Tilledgrounddid not seemto make much difference in providing a less hospitable environment for the larvae to complete their life cycle. What some farmers found was that small



ground-based predators consumed the larvae much faster if the soil was not disturbedandthefieldhadnotbeensprayedbefore·

Dr. John Gavloski – Manitoba Agriculture’s Provincial Entomologist –provided me with the following comments when I asked him recently about this wheat midge issue:

‘I have never seen a peer-reviewed article linking increases in wheat midge levels to zero-till. So, this is anecdotal at best. There has been some research on ground-based predators feeding on wheat midge larvae. Ground beetles (Carabidae) prey on wheat midge larvae, and a study in Saskatchewan found 14 species of ground beetles feeding on wheat midge larvae (Floate et al., 1990. Environmental Entomology. 1503–1511). Four of these species were tested in lab studies with no alternate prey (just wheat midge larvae) and consumed 9, 15, 43, and 48 midge larvae per beetle per day respectively. I doubt they consume these levels in the field, where searching time and alternate prey would be factored in, but it does show that when wheat midge levels are high predation by ground beetles can certainly help reduce levels. The authors of this study estimated that daily predation in the field from all species of ground beetles combined ranged from < 1 to 86 midge larvae/m2. Most of this predation would occur during June and August.

I agree that farmers can get themselves in a trap (where they actually inflate long-term pressure from wheat midge) by applying insecticides for wheat midge when not needed. Likely a large part of what is happening is that in addition to predators they are damaging populations of a natural egg-larval parasitoid of wheat midge called Macroglenes penetrans. Research in Saskatchewan found they controlled an average of 31.5% of wheat midge across Saskatchewan (Olfert et al., 2009). Research in North Dakota found parasitism rates averaged 22% and ranged from 0 to 100% over the 12-year period.

Entomologists in Alberta have noted high levels of Macroglenes penetrans when sweeping canola fields that were wheat the previous season. They would be emerging in the current year’s crop (in this case canola) and searching for wheat fields and wheat midge to parasitize. So unnecessary insecticide applications to canola could not only affect predators and parasitoids of the canola pests, but in this case (where there was wheat the previous year) may impact regional levels of Macroglenes penetrans. This is another example of why using economic thresholds and minimizing unnecessary insecticide applications can be the most economical strategy for a farmer in the long-term.’

It is my observation that we do not really know why orange blossom wheat midgebecamesuchasignificantproblem25yearsago.Itmayhavejustbeena coincidence that it happened at the same time no-till farming was taking off. However, it seems that once we got a few years into the no-till system there was enough biodiversity in the soil to help keep the insect pest in check. I personally have not sprayed for wheat midge in 24 years – but back then we sprayed4or5yearsinarow.Thereareareaswherewheatmidgecontinuesto remain a problem and there are now more effective genetic and chemical methods for control of the pest, but I believe maintaining undisturbed topsoil helpssignificantlyinthebio-controloftheinsectaswell.Thesenaturalcontrols



havehelpedkeepmidgeatoveralllevelswhicharemuchlesssignificantthanthey were 25 years ago.

At that same timeduring the adventof no-till on theCanadianPrairies,cruciferfleabeetleswerealreadyasignificantproblemincanola–thiswaseventhough very potent insecticides were being used at that time with the seed. TothisdayvirtuallynocanolaisseededonthePrairieswithoutaninsecticide,primarily because of this insect, but some of the most effective insecticides are nolongerinuse.Itismyobservationthatno-tillmayhavehelpedstabilizefleabeetle populations. It is unreasonable to say that no-till on its own will control fleabeetlesbecause that just isnot thecase.Onmy farmandothers in theregion the pest is still a serious concern despite many years without tillage, and applying insecticides while seeding is still very important. However, we have only needed to spray for the insect once in the 25 years since we stopped tilling theland,whilebeforethentheneedtospraywasaregularoccurrence.Thiscould be attributed to more effective seed treatments in recent years too but, regardlessoftheotherreasonsfortheinsect’scontrol,theeliminationoftillagein the farming systemcertainlydidnotmake the situationworse.This is theopposite of what many felt would happen 25 years ago when tillage was taken out of the seeding process. It was felt then that undisturbed soil would simply beabetterenvironmentforthefleabeetletoexistandproliferate.Thankfullythat does not seem to have been the situation:

The following are observations recently lifted directly from the CanolaCouncil’sOfficialwebsite:

‘Tillage: Flea beetles prefer bright relatively warm conditions. Direct seeding provides a microclimate that is less ideal for flea beetles than tillage before seeding. Planting into stubble may provide a microclimate that is cooler, moister and less favourable to flea beetles. Injury may be reduced due to the cooler microenvironment created by stubble shading on surface soil. Cooler temperatures at the soil surface slow flea beetle activity reducing damage. However, crop development can also be slowed by cooler temperatures, so frequent crop scouting is still essential to ensure damage thresholds are not exceeded.

In Alberta, zero till canola production can reduce flea beetle damage to levels equivalent to those found with the use of insecticidal seed treatments. This seeding method produces large plants early and may reduce the grower’s dependence on seed treatments and foliar insecticides, except under conditions of intense flea beetle pressure.’

With the indiscriminate spraying of insects, we are often upsetting a balance or equilibrium that we do not fully understand. This is different to theindiscriminate spraying to control weeds or disease where the main risk is simply eventual resistance of that plant or disease. It is vital to preserving a healthyandbiodiverseecosysteminyourfieldsthatyouonlysprayinsecticideswheneconomicpopulationthresholdshavebeenexceeded(Fig.5).



Ifwelookspecificallyattheeconomicbenefitsofnothavingtosprayforthose insects because they are already being controlled to some degree by the biodiversity found within the soil, we can assume the following savings: TotalcostsforwheatmidgeorfleabeetlecontrolaregenerallyCanadian$8per acre for the product and $9 for the application cost which equals about $17 an acre for treatment. There are often 45million acres of wheat andcanolaplantedinCanadaeachyearso,withoutthebiologicalreductionofthesetwo insects (andother insectsaswell) fromthebiodiversity inPrairiesoils, there would be hundreds of millions of dollars in extra production costs requiredtogrowthesecropseachyear.Thisextrasprayingwouldalsolikelycome with unintended negative impacts to the general insect community. Keep inmind that thissimpleandsingularexample is just forCanada; theimplications worldwide for these crops would likely be in the billions$ of extra costs not to mention the environmental impacts of that excessive need for insecticides!

InthenorthernRegionsofNorthAmerica,thelastglacierwasonly8000–10000yearsago.AlmosttheentireNorthernPlainswascoveredinasheetoficeupto2kmthick.Thisglacieressentiallykilledwhateverearthwormswereinthe soil at the time. It has been determined that most of the earthworms we see inahandfuloftopsoilinWesternCanadacanbenowattributedtoearthwormeggsbeingdistributedacrossthePlainsontherootsoftreesbeingprovidedfor new farm yard shelterbelts. Much of the seed stock for these shelterbelt trees came from Eastern Europe over 100 years ago and that is probably where mostofourcurrentearthwormshaveoriginated.Therearecountlessarticles

Figure 5 FleaBeetledamagetocanolaseedlings.



thattalkabouttheimportanceofearthwormsinahealthyno-tillCAsystemandhowCAcontributestotheincreaseinearthwormnumbersinthesoil.

I can say with certainty that earthworm numbers have increased dramatically sincewestoppedtillingthelandonourfarm.Therearetimeswhenearthwormnumbersaresohigh,theyappeartobenow‘dripping’offtheseedingopenersof our air seeder whenever we lift the unit out of the ground. In my youth when wetilledourfieldstheonlyplaceyouwouldfindmanyearthwormsonourfarmwas in the garden in the spring. Earthworms improve the internal drainage of the soil, they improve the nutrient cycling within the soil, they contribute to the organicmatter,theyconsumecropresidues,andthelistgoeson.Tillageistheenemy of the earthworm and like many other farms we have seen their increase since we stopped tilling.

I would like to mention we have also used exclusively anhydrous ammonia (NH3) asournitrogen sourceonour farmover thepast 40 years.TheNH3is banded 4 cm to the side and 4 cm below the seed row while seeding and the seeding rows are spaced 25 cm apart. While the soil biota will be disrupted in thatnarrowbandofNH3 every 25cm – there is obviously plenty of unaffected soil between the seed rows that allow the soil to return to equilibrium quickly and the high earthworm population to remain relatively stable. Seeding with NH3isverycommoninmylocalregionbutisnotcommonacrossallthePrairies.ThelackoflocalinfrastructureforsupportingtheNH3 is part of the reason it is nolongerusedextensively(Figs.6and7).

The Northern Plains of North America are sometimes called the ‘DuckFactory’of thecontinent.Migratingwaterfowlofall typesreturntothis largeregion after overwintering in the South to nest amongst and near the millions ofpotholesand temporarywetlands thatdot thePrairie landscapeafter the

Figure 6 Earthwormshavebecomeabundantinourno-tillfields.



snow melts each spring. The advent of no-till has provided a much betterhabitat for thesegroundnestingbirds compared towhenfieldswere tilled.This improvement inhabitatwithno-tillhasmotivatedDucksUnlimited (DU)– the waterfowl conservation company – to focus much of its activity on the promotion andperfection of no-till farming systems.DU, alongwith severalgovernment and farmer initiatives focusing on no-till research and extension, wasinstrumentalintheadoptionofno-tillonthePrairiesgoingbackover30years.Therearemanystudiesdoneby thebiologists thatworkwithDUthatsupports their work in no-till promotion as an excellent tool in their goals of improving the habitat and increasing the populations of Prairie waterfowl,upland birds and shore birds.

It appears that the use of no-till along with fall seeded crops provides the best nesting environments in crop production agriculture for many of these migratingbirds.DUbiologistsinSouthernAlbertahaveseenthatevenfinickyshore birds like the long-billed curlew have been nesting in no-till winter wheat crops at levels similar to their native prairie nesting densities. It is the practice of combining winter crops such as winter wheat, fall rye and winter triticale with a no-till farming system that provides the best habitat for ground nesting birds. This isprimarilybecause there isbasicallynoactivityon that fieldwhen thebirds are nesting in the spring because the crop is already growing. With spring seededno-tillfieldsthequalityofthenestinghabitatisalmostasgoodbuttheseeding process itself will often destroy many of the nests.

Incultivatedfieldsthenestingofbirdsisoftennotassuccessfulbecausewith so little residue left on the soil surface it is hard to disguise their nest

Figure 7 OurairseederwithNH3.



frompredators.Also,thecolor,lookandfeelofacultivatedfieldissoforeignto these birds compared to the native grasslands where they once nested. Winter crops planted in a no-till system is the closest they are going to get toanativegrasslandenvironmentbutstillbenestingonfieldsthatproducecrops and food. Winter crops used in a conjunction with a spring seeded crops provideexcellentdiversity to thePrairie cropping system. It is likehavingacover crop that you get to harvest for income as well. However, the value and poor economics of those winter crops at this time have made them much less attractive than they were even 5 or 6 years ago. Hopefully that cycle will rebound, and winter cereal crops will once again be popular in Western Canada(Fig.8).

A few years ago, while seeding canola into thick and tall undisturbed wheat stubble, I came across this nest of the ground nesting ‘marsh hawk’(alsoknownas the ‘northernharrier’).This issomething Ihadneverseenoncultivated land before as these hawks generally only nest in tall grass near marshesandswamps.Theirpresenceisappreciatedbyfarmersandothersfortheircontroloffieldrodentsandevengrasshoppersandotherpests.Icarefully

Figure 8 MallardDucknestinbarleystubblethathasbeenseededtocanola–ourfarmyard is in the background.



seeded around this nest, so it was left undisturbed and hopefully those chicks arenowadultsfeedingonvariousvermininmyfieldswhentheyreturneachspring.Thisisanexampleofabeneficialbirdthatwouldnothavenestedinatilledfield(Fig.9).

Inadditiontoducksandhawkswealsofindamyriadofotherprairiebirdsnestinginno-tillfields.Someofthemostcommonarekilldeer,sandpipers,andplovers. Once again, their nesting densities and successes seem to be much higheronourno-tillfieldscomparedtowhenweusedtotill theland.Otherfarmers in my region have observed these same results.

Alongwith the birds, earthworms, beneficial ground beetles andmanyother soilorganisms that seem tonowbeflourishing inourno-till fields theother phenomenon I have observed in recent years is the return of many large mammalstoourlandscape.Thiscannotbeattributedtono-tillonitsown,butour reduction or elimination of tillage that started 25 years ago certainly has not deterredwildlifebecomingmoreprevalentontheCanadianPrairielandscape.

On our farm virtually all the trees have been planted by my family or other humans.Whenourfamilyfirsttookoverthefarminthemid-1930s,youcouldnot see a tree on the farm as it was simply some farm building sticking out amongstavastseaofgrass.DespitethefewtreesandthelargeswathsofopenPrairie,Ihaveseenoverthepastfewyearsmanyanimalsonornearourfarmthat one would associate with more forested areas: moose, elk, whitetail deer, coyotes, foxes, wolves, and even black bears and mountain lions have been observed(andcausingproblems)onlyafewkilometersfromourfarm.

Figure 9 MarshHawknest.



However, the really exciting recent observations for me are the open Prairiemammals thathavereturnedtoour farm:pronghornantelope (whichhavenotbeenofficiallyseeninourregionfor130years)andmuledeer(notofficially seen inour region for60years)havenowbeenonour farm in thepast few years. If you were to come to our small community, outside of winter, I could almost guarantee I would be able to show you many of the animals I havementioned(exceptthebearandmountainlion)withina24-hourperiod.ThereisnowamoreconcertedefforttoprovideproperhabitatandtherearemanyprogrammesthatarehelpingtosupportwildlifeonthePrairiessuchasthe recent initiative fromDucksUnlimited.However,another reasonwemaybe seeing this upswing in wildlife is because no-till has been implemented at the same timewe have simply less people living on the land. Farms aremuchlargernowandmanyfarmyardshavebecomeabandoned.Thesesmalldiverse woodlands where farm families once lived can provide excellent habitat for some of these larger animals. In addition to these old yards we now havelargestretchesofrelativelyundisturbed(no-till)farmlandinbetweenallthesepocketsofwoodedhabitat.Theseuncultivatedfieldsprovidepredatorswithabetterchanceoffindingsmallmammalslikemice,gophersandthosenesting birds and eggs that have been already mentioned. You essentially have,withno-tillCAlandscape,abettersourceoffoodinbetweenthepatchesofprotectivehabitatcomparedtowhenfieldswerealwaystilled.Whenfieldsare left untilled it is like having more restaurants on the route between your destinations(Figs. 10–13).

Tillagedoesnotexistinnature.Therefore,itstandstoreasonthatnaturehas evolved to appreciate/thrive in a soil that is left as undisturbed as possible. These undisturbed conditions provide the best possible environment forbiodiversity to reach its full potential in any cropping system. Adding diversity tothatno-tillCAcroppingsystemwithwinterandsummercrops,usingdifferentcrop species, utilizing cover cropping where appropriate, and including forages and grazing where possible greatly enhances this environment for the soil biology and the overall biology of a region. However, it is the elimination of tillage that is key to getting this all started and providing the base to build a biologically diverse farming system above and below the soil surface.

ThefollowingsectionisfromtheFAOpublication‘TheStateoftheWorld’sBiodiversityforFoodandAgriculture’(FAO,2019,p448):

‘Diversification and management practices at production level:The use of a number of diversification strategies in food and agricultural

production systems seems to be increasing. Evidence indicates that agroforestry is becoming more widespread in all regions of the world. Priorities in terms of strengthening the contributions of agroforestry to sustainable development include addressing problems in germplasm supply, improving the provision of marketing advice and developing a better understanding of gender-related implications. Home



gardens are major reservoirs of biodiversity for food and agriculture (BFA) in many parts of the world. However, knowledge of the status and trends of these systems is limited. In the case of diversification in aquaculture, while traditional extensive diversified systems are tending to decline as a consequence of resource constraints, innovative polyculture approaches are creating opportunities to increase efficiency

Figure 10 MooseinmyCanola.

Figure 11 Coyoterunningacrossno-tillwheatstubbleafterhuntingformice.

BDS_Ch9_Cons_V2_CED_docbook_new_indd.indd 26 27-12-2019 10:14:15



and tackle problems related to fish health and effluent discharge. Integrated crop–livestock systems remain widespread globally. There is need for research into how complementarities between crop and livestock production can be enhanced in the context of limited availability of land and other resources, including research into the significance of within-species genetic diversity. The use of many management practices believed to help promote the conservation of BFA, or that utilize BFA in a sustainable way, is reportedly increasing, as is awareness of the benefits of such practices among consumers, producers, governments and international agencies. This appears to be the case, for example, for organic agriculture, low external input agriculture, management practices implemented with the aim of preserving

Figure 12 Pronghornonourfarm.

Figure 13 Mooseinmywheat.

BDS_Ch9_Cons_V2_CED_docbook_new_indd.indd 27 27-12-2019 10:14:16



and enhancing soil biodiversity, conservation agriculture, integrated plant nutrient management, integrated pest management, pollination management and sustainable forest management practices. Nevertheless, the availability of global data on the levels of implementation of many of these practices remains limited, and knowledge of their impacts on BFA and the supply of ecosystem services needs to be improved. Biodiversity-based and biodiversity-friendly management practices generally require detailed knowledge of local production systems and ecosystems and are often relatively labour intensive. Consequently, their implementation tends to require the active participation of producers and their organizations, as well as the presence of effective extension services. Management interventions often need to extend beyond farm boundaries into the broader landscape or seascape. Attention needs to be paid to maintaining or restoring ecosystems that deliver services to food and agriculture and conserving the species and genetic diversity that will allow adaptation to changing conditions’.

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