Flora and Vegetation of the Saint David and Lewis Springs ... (post-monsoon photo taken in October...

USDA Forest Service Proceedings RMRS-P-67. 2013 71

In: Gottfried, Gerald J.; Ffolliott, Peter F.; Gebow, Brooke S.; Eskew, Lane G.; Collins, Loa C., comps. 2013. Merging science and management in a rapidly changing world: Biodiversity and management of the Madrean Archipelago III; 2012 May 1-5; Tucson, AZ. Proceedings. RMRS-P-67. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

Flora and Vegetation of the Saint David and Lewis Springs Cienegas, Cochise County, Arizona

Elizabeth Makings School of Life Sciences, Arizona State University, Tempe, Arizona

Abstract—In the Sky Island region, cienegas are rare marshlands amidst arid surroundings where ground-water perennially intersects the surface. Their unique physical properties give rise to a characteristic plant community dominated by wetland graminoids. Evaporation usually causes the water to be alkaline, and vegetation around a cienega commonly includes halophytes and other unusual species. Depending on their age and size, they may also harbor high levels of endemism. Cienegas are far from pristine, and like many wetlands and riparian areas, they have probably been exploited for millennia. In the American Southwest, these habitats are hypothesized to have been in severe decline over the past 150 years due to a variety of man-made factors. In light of their biological and cultural importance, it is important to learn as much as we can about their current condition and conservation potential.

Introduction Cienegas, described byHendrickson andMinckley (1985), aremid-elevationwetlands(3280-6560ft.)characterizedbypermanent,scarcelyfluctuatingwatersourcesamidaridsurroundings.Theaquiferdynamics,floral,andfaunalcharactersofcienegasareuniqueandvaryaccordingtoregionalgeomorphologicalandecologicalconstraints.Cienega-typemarshesandwetlands formwhere layersof rockorimperviousclayholdwateratthesurfaceorthroughthecontinuousupwellingofnumeroussmallspringsandseeps(USDI2012).Ciene-gascanbeverylargeandharborhighlevelsofendemism,suchasCuatroCienegasinCoahuila,Mexico,withanareaofapproximately208,000acres(325mi2);orsmallandcryptic<2acres(0.003mi2),suchastheLewisSpringsCienegainCochiseCounty,Arizona. Thesoilsofcienegasaretypicallyfinelytextured,andhighlyor-ganic.Moisture,salinity,andotherabioticfactorsarealsoimportantinfluencesonspeciescomposition.Theresultisacharacteristicsuiteofplantsspeciallyadaptedtotheseconditions,arareplantcommunitydominatedbywetlandgraminoids(monocots)inthreemainfamilies:grasses(Poaceae),rushes(Juncaceae),andsedges(Cyperaceae).

Saint David Cienega TheSanPedroNationalConservationArea(SPRNCA)isanarrowstripwithapproximately40milesofstreamrunningfromtheMexicanbordertothetownofSt.David,Arizona.Amongtheplantcommuni-tiesoftheSPRNCAaretwoseparatecienegahabitats:theSt.David

Cienegaatthenortherntipandalittleknown,muchsmallerwetlandnearthemiddleassociatedwiththeLewisSpringsandGovernmentDrawdrainages(fig.1). TheSt.DavidCienegaisamarshyflatofapproximately350acreswithaperimeterof2.3miles.Seasonalityisanimportantfactor,andcienegascanvarydramaticallydependingontimeofyear.Themainportionofthewetlandwithpermanentwaterisabout75acres(figs.2,3). Surrounding vegetation is a mixture of mesquite grasslands,bosques,andChihuahuandesertscrub.SaintDavidCienegawouldbecompletelyvegetatedwithnovisiblesurfacewater;however,thereiscurrentlyactivemanagement(vegetationremovalandearthmoving)inanorthwestportiontoprovideopenwaterfornativefishandfroghabitat(Simms,personalcommunication).Figure4isalandscapeschematicofthevegetationzonesoftheSt.DavidCienega.Speciesassociationsareinfluencedbyamoisturegradientfromperenniallysaturatedsoilsinthemiddle,wherethewaterintersectsthesurface,toaseasonallydryandincreasinglysalineperiphery.Schoenoplectus americanus (chairmaker’sbulrush) formsnearlyimpenetrablestandsthroughoutthemiddleportion,associatedwithLythrum californicum (Californialoosestrife), and Berula erecta (cutleafwaterparsnip).Thiszonehasankle-deepwaterthroughoutwithorganic,blacksoils(fig.5).Movingoutward,denseclumpsofCarex praegracilis(clusteredfieldsedge)dominatealongwithEleocharis rostellata(beakedspikerush)(fig.6).AmixofMuhlenbergia asperifolia (alkalimuhly),Distichlis spicata (saltgrass),andJuncus arcticus var. balticus (Balticrush)canbefoundinthe“Juncus-Distichlis”zone;transitioningintoanareaoftallgrassessuchasSporobolus wrightii (sacaton),Panicum obtusum (vinemesquite), andBothriochloa laguroidesssp.torreyana(silverbeardgrass).Mesquite(Prosopis velutina)andsacatonoutlinemuchoftheperimeterofSt.DavidCienega. Therearenaturallyvariousspeciesthatcanbepatchyandlocallyabundant,suchasAnemopsis californica(yerbamansa),Asclepias subverticillata (whorledmilkweed) and Helianthus annuus(commonsunflower).InthenorthwesternsectionofthecienegaTypha domingensis

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Makings Flora and Vegetation of the Saint David and Lewis Springs Cienegas, Cochise County, Arizona

Figure 1—St. David and Lewis Springs Cienegas within the San Pedro National Conservation Area.

Figure 2—St. David Cienega looking northwest; Whetstone Mountains in the background (photo taken July 2005).

Figure 3—Similar perspective of St. David Cienega (fig. 2) taken April 2012.

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Flora and Vegetation of the Saint David and Lewis Springs Cienegas, Cochise County, Arizona Makings

Figure 4—Schematic of St. David Cienega vegetation zones.

Figure 5—Nearly impenetrable stands of chairmaker’s bulrush (Schoeno-plectus americanus) in Middle portion of St. David Cienega.

Figure 6—Mats of clustered field sedge (Carex praegracilis) in the ‘Carex-Eleocharis’ zone of the St. David Cienega.

(southerncat-tail)replacesS. americanusasthedominantwetlandgraminoid. Cyclesofsaturationandevaporationtendtomakesoilsalkaline,andvegetationincienegasalmostalwaysincludeshalophytesandotherspecializedplants.TheSt.DavidCienegahasnumerousex-amplesofspecieswithhighfidelity tocienegas—theirvernacularoften indicating salt tolerance e.g.,Almutaster pauciflorus (alkalimarshaster),Distichlis spicata (saltgrass),Muhlenbergia asperifolia,Pluchea odorata (saltmarshfleabane),Symphyotrichum subulatum var. ligulatum (saltmarshaster), Suaeda moquinii (seablight),etc.

Afloristicinventorywasconductedduringtheearly2000’softheSPRNCAand625taxawerevoucheredfromthatstudy(Makings2006).Table1isalistof23ofthosefromtheSt.DavidandLewisSpringsCienegas thatwere foundnowhereelsebut in these twohabitats.Some,nodoubt,canbedismissedassimplyrareand/oroverlookedinthegreaterSPRNCA,butothersmightbeconsideredtruecienegaindicators.Forexample,inCochiseCounty,Almutaster pauciflorus,Ammannia coccinea,andMuhlenbergia asperifoliahaveonlybeencollectedfromcienegasoftheregion.Usingbiodiversityoccurrencedata accessed through the Southwest Environmental Information

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Makings Flora and Vegetation of the Saint David and Lewis Springs Cienegas, Cochise County, Arizona

Figure 7—Lewis Springs Cienega looking northeast. Most abundant spe-cies are Juncus arcticus var. balticus and Lythrum californicum (California loosestrife) (post-monsoon photo taken in October 2011). Grass along perimeter is mostly alkali sacaton (Sporobolus airoides).

Figure 8—Eryngium sparganophyllum (Arizona eryngo).

Network (SEINet 2012), this overlapping distribution pattern isconsistentwithmanyothertaxaintable1.InadditiontothecienegasoftheSanPedro,theyregionallytendtobefoundinsuchplacesasEmpireCienegainLasCienegasNationalConservationArea(PimaCounty),O’DonnellCienegaintheCaneloHills(SantaCruzCo.),SanRafaelStateNaturalArea(SantaCruzCounty),HookerCienega(CochiseCounty),andPipeSpringsCienegaintheSanBernardinoNationalWildlifeRefuge(CochiseCounty).

Lewis Springs Cienega TheLewisSpringsCienegaisapproximately1300ft.eastoftheSanPedroRiverandjustsouthof theLewisSprings/GovernmentDrawdrainage.Itisanunlikelywetlandsituatedonthesideofasmallslope,probablymaintainedbygravity-drivensubterraneanflowfromsurroundinguplands.Themarginsofthewetlandareabruptandthecontrastofdesertvs.wetlandvegetationisespeciallyevidentinthedryermonths(fig.7). TheLewisSpringsCienegaisa little less than2acres,buthasyieldedseveralspeciesofinterest,includingonesthatappeartobelimitedtothistinywetland.Forexample,Lobelia cardinalis(car-dinalflower),anobligatewetlandspecies,isonlyknownfromthisisolatedpopulationatLewisSprings, andnowhereelsealong theSPRNCAfloodplain.Alsonotable,isAndropogon glomeratus(bushybluestem),atallperennialgrassthatisrareregionally,butabundanthere.‘Cienegaindicators’suchasAlmutaster pauciflorus, Anemopsis californica, Lythrum californicum, Mentha spicata (spearmint), and Muhlenbergia asperifolia arealsoonlypresenthereorintheSt.DavidCienega,andnotinthegreaterSPRNCA.

Table 1—Species found only in cienega habitats within SPRNCA.Species Cienega locationAlmutaster pauciflorusa St. David / Lewis SpringsAmmannia coccineaa St. DavidAnemopsis californicaa St. David / Lewis SpringsBerula erectaa St. DavidCalystegia sepiuma,b St. DavidCarex praegracilisa St. DavidChamaesyce prostrata St. DavidCirsium vulgare St. DavidCyperus spectabilis St. DavidDistichlis spicataa St. DavidEleocharis rostellataa St. DavidElymus trachycaulusa St. DavidEpilobium ciliatuma St. DavidEryngium sparganophylluma Lewis SpringsLeptochloa fusca ssp. fascicularisa St. DavidLobelia cardinalis Lewis SpringsLythrum californicuma St. David / Lewis SpringsMentha spicataa St. David / Lewis SpringsMuhlenbergia asperifoliaa St. David / Lewis SpringsPluchea odorataa St. DavidPluchea sericea St. DavidSamolus valerandi ssp. parviflorus St. DavidSisyrinchium demissum St. DavidaHigh fidelity to cienegas and similar wetlands.bState record.

Themost noteworthy species in the Lewis Springs Cienega isEryngium sparganophyllum (Arizonaeryngo),anunusualdicotintheApiaceae.Eryngium sparganophyllumisaperennialherbwithabasalrosetteoflong,parallel-veinedleaves.Theflowersarecreamandclustered indenseheadsat theendof thebranching,scaposeinflorescences(fig.8).Eryngium sparganophyllumisarare,regionalendemicthatoccursinmarshesandotherriparianhabitats.SEINetdata shows only 15 collections of vouchered material from theregion—InArizona,fromPimaandCochiseCounties;InMexico,one locality each from Sonora, Coahuila, and south to Durango(fig.9).OtherbiodiversitydatasuchasNatureServe(2012)reporttheglobalrangetoincludeZacatecasandJalisco,whichwouldbeslightlyfarthersouth,butregardlessofitsdistributionallimits,thescantnumberofcollectionssuggestsararelifehistorystrategyforthisspecies.Eryngium sparganophyllumcanreachaheightof>5ft.andisconspicuouswhenflowering,andtherefore, it ishardtoimaginethatthisplantisoverlookedinthefield.Infact,thereare

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Flora and Vegetation of the Saint David and Lewis Springs Cienegas, Cochise County, Arizona Makings

anecdotalcommentsonseverallabelsnotingitslocalizedabundance(e.g.,Yatskievychin1982:“dominantinmarshymeadow”;Reinain2003:“verycommonherbaceousperennial”;Wiensin2008:“locallycommonherbaceousperennial…”Thelimiteddistribution,coupledwithsuchnarrowecologicalparameters,alsomakeE. sparganophyl-lum especiallysusceptibletolocalextinction,earningitsstatusas“criticallyimperiled”inArizona,and“possiblyextirpated”inNewMexico(NatureServe2012).Indeed,WootonandStandley,intheirtreatmentoftheNewMexicoflorain1915,notetheonlycollectionofE. sparganophyllum,aCharlesWrighttypespecimenfrom“LasPlayasSprings,neartheSierradelasAnimas,NewMexico,”probablythepresentdayPlayasValleyeastoftheAnimasMountainsintheNewMexico“Bootheel”(WootonandStandley1915).Inadditiontothispopulation,probablymanyothershavebeenextirpatedduetodewateringofwetlandsintheregion.

Discussion Cienegasandtheirenvironshavebeeninhabitedformillenniaandhavegreatarchaeologicalandbiologicalvalue.However,thefutureofcienegasisuncertain,havingbeengreatlyreducedoverthelast150yearsmainlyduetotheinfluencesofhumans.CienegasmaybeoneofthemostendangeredhabitatsintheAmericanSouthwestandnorthwesternMexico,manyonlyremnantsoftheirhistoricalcondition.

HendricksonandMinckley(1985)estimatehabitatlossofcienegastobeupwardsof95%,makingthemaquaticislandsinanaridmatrix.FrankCrosswhite,editorofDesertPlantsatthetime,noted,“Cienegasiteswerethefirsttobeusurpedbyland-hungryHispanicsandAnglosalikewhodevelopedlargeherdsofcattletodevourthevegetationanddrinkthewater.Overgrazingmadethecienegalocationsamongthemostmistreatedsitesonearth.Avarietyofmisfortunes,broughtabouteitherknowinglyorunconsciouslybyman,haveresultedindrain-age,arroyocutting,andgeneraldestructionoftheseuniquehabitats”(Crosswhite1985).Cattlegrazing,development,andassociatedwaterextraction(groundwaterpumping,draining,diverting,impounding,etc.)continuetobeproblemsandhaveincreasinglyplacedpressuresontheecologicalintegrityofmanycienegas,includingthosealongtheSanPedroRivervalley. Cienegasarerelativelysmallecosystemswithimportantrolesonthelandscape,yetironically,poorlyunderstood.Inordertoassesstheirimportanceandconservationpotential,betterknowledgeregardingproperfunctioningofthesesitesiscritical,includinginvestigationoftheirextent,ecology,andabioticparameters,aswellasmonitoringtheirtrends.ThesurvivaloftheSt.DavidCienega,LewisSpringsCienega,andotherrarewetlandsoftheregionwillultimatelydependon(1)ademandforthoughtfulchoicesaboutwhereandhowmuchgroundwaterispumped,(2)greateremphasisonresearch,and(3)oursupportofeffortstoprotectandrestorethem.

Figure 9—Distribution of Eryngium sparganophyllum with locality (collector and date).

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ReferencesCrosswhite,F.S.1985.Editorial.DesertPlants6(3):130.Hendrickson,D.A.andW.L.Minckley.1985.Cienegas—vanishingclimaxcommunitiesoftheAmericanSouthwest.Desert Plants6:130-175.

Makings,E.2006.FloraoftheSanPedroRiparianNationalConservationArea.DesertPlants22(2):104p.

NatureServe.2010.NatureServeExplorer:Anonlineencyclopediaof life.Version 7.1. Arlington, Virginia. http://www.natureserve.org/explorer[April-June2012].

The content of this paper reflects the views of the authors, who are responsible for the facts and accuracy of the information presented herein.

SEINet. 2012. Southwest Environmental Information Network,http//:swbiodiversity.org/seinet/index.php[April–June2012].

Simms, J.2012.Personal communication.FisheryBiologist,UnitedStateBureauofLandManagement,Tucson,Arizona.

Wooton,E.O.andP.C.Standley.1915.FloraofNewMexico.ContributionsfromtheUnitedStatesNationalHerbariumVolume19.Washington,DC.794p.

U.SDepartmentoftheInterior.2012.LandCorral/St.DavidCienegaTrail.Washington,DC:U.S.DepartmentoftheInterior,BureauofLandMan-agement.Online:http://www.blm.gov/az/st/en/prog/recreation/hiking/stdavid.html[June2012].