Researchers: Aregmi Amigon, Samia Uddin, Lucy Royte ...… · Figure 2: Soil depth is posi/vely...

Introduc)onGreenroo'opsarepossiblesolu/onstomanyproblemsfacedbyurbanenvironments.Waterrunoff,poorairquality,andhightemperaturesareonlyafewoftheproblemsthatplagueNewYorkCity.Withdifficultgrowingcondi/onsonroofs,itisimportanttoensurethatgreenroofsareconstructedinawaythatwillpromoteplantsurvivorship.Theimportanceofsoildepthhasbeenshowntoimpactplanttypeandgreenroofeffec/venessinallevia/ngtheseenvironmentalproblems.Deepersoilallowsmoreroomforrootstogrow,thustallerplants,aswellasthecapacitytoretainwater,whichprovidesaccesstoplantsandreducesstormrunoff(Oberndorfer2007).Nitrogen-fixingplantshouserhizobium–anitrogen-fixingbacterium–andcanenrichthesoil,whichfacilitatesthegrowthofplants(Maron1996).Harshroo'opgrowingcondi/onsemphasizetheimportanceofnutrientrichsoil.Ourteamwasinterestedinhowsoildepthandthepresenceofnitrogen-fixersaffectspeciesrichnessandtotalcover.Withourresearchwehopetocontributetotheunderstandingofgreenrooftechnologyandimplementa/oninNewYorkCity.

MaterialsandMethods InMayof2010,tengreenroofswereconstructedonNYCParksDepartmentbuildingsthroughoutthecity.Westudiedandcollecteddatafromsevenroo'opslocatedinQueens,ManhaYan,StatenIsland,andtheBronx.Eachroofhad24splitplots,twelveeachofHempsteadPlainsandRockySummitplantassemblages.Sixoftheplotsoneachroofhadagrowingmediumof4inches,whereastheremainingsixhadadepthof6inches.

Acknowledgments#Trueroofs would like to thank the Wildlife Conservation Society and Prospect Park Zoo for the use of their facilities and wonderful staff member Kimesha Reid-Grant, who helped us network and provided us with indispensable wisdom. We would also like to thank Fordham University for the use of Ram Vans and the Rose Hill and Calder campuses. Generous support was also provided by the National Science Foundation. Many thanks to Matthew Iannone, Acer Van Wallendael, Megan Henriquez, and Jason Aloisio for their generosity, guidance, plant identification skills, and putting up with our shenanigans. Finally, a big thank you to the NYC Parks Department for the use of their recreation centers.

DiscussionOriginally,thegreenroofteamhypothesizedthatbedswithagreatersoildepthwouldhaveagreaterplantspeciesrichness.A'eranalysis,however,thedatacollecteddidnotfullysupportourhypothesis.Asshowninfigures1and2,plotswithgreatersoildepthhadaminimalcorrela/onwithspeciesrichness.Wealsohypothesizedthatbedsthatcontainatleast25%nitrogenfixerswouldhaveagreatertotalpercentcover.ThedatainFigure3supportsthistrend,althoughit’srela/velyskewedwithsomanyplotsat0%nitrogen-fixers.Despiteaweakcorrela/on,theRockySummitdidsupportouroriginalhypothesis,asshowninFigure4.Thelasthypothesiswassupported,despiteaweakcorrela/onbetweennitrogen-fixingplantsandthemeanswardheight,visibleinFigures5and6.Overall,thedatacollectedcouldnotfullysupportourhypothesisduetotherestricted/mealloYedoneachroof,limiteddata,andoutsidefactors.Withmore/meanddata,thetrendsthatweexpectedwouldmostlikelyhavebeensupported.

LiteraturecitedAloisio,J.M.“Roo'opPlant:CommunityandNutrientDynamicsof

NewYorkCityGreenRoofs.”UnpublishedDisserta1on(2016)Maron,J.L.&Connors,P.G.“Ana/venitrogen-fixingshrub

facilitatesweedinvasion”Oecologia(1996)105:302.doi:10.1007/BF00328732

Oberndorfer,Erica.“GreenRoofsasUrbanEcosystems:EcologicalStructures,Func/ons,andServices.”BioScience57,no.10(2007):823-33

Researchers:AregmiAmigon,SamiaUddin,LucyRoyte,MalcolmWansley,Mentors:Ma@hewIannone,AcerVanWallendael,KimeshaReid-Grant,andJasonAloisio

Hypotheses•  Subplotswithagreatersoildepthwillhavegreaterspecies

richness•  Subplotsthatcontainatleast25%nitrogenfixerswillhavea

greatertotalpercentcover•  Subplotswithatleast25%nitrogenfixerswillhaveagreater

averageswardheight

Results

Figure1:Soildepthisposi/velycorrelatedwithspeciesrichnessintheHempsteadPlainssubplots,butthecorrela/onisonlymarginallysignificant(r=0.195,p=0.088).

Figure2:Soildepthisposi/velycorrelatedwithspeciesrichnessintheRockySummitsubplots,butthecorrela/onisnotsignificant(r=0.072,p=0.530).

Figure3:Thepercentofnitrogen-fixingplantsisposi/velycorrelatedwiththepercentoftotallivingplantcoverintheHempsteadPlains,andthecorrela/onissignificant(r=0.235,p=0.041).

ConclusionsInconclusion,thedatasupportourhypotheses,butweobservedahighlevelofvaria/on.Inallofourcorrela/ons,thereisindica/onofatrend,butitislikelythatwehavenotaccountedforallvariables.Furthertes/ngwouldberequiredinordertohaveabeYerunderstandingonhownitrogenfixingplantsandsoildepthaffectgreenroofvegeta/on.

Figure4:Thepercentofnitrogen-fixingplantsisposi/velycorrelatedwiththepercentoftotallivingplantcoverintheRockySummit,butthecorrela/onisnotsignificant(r=0.075,p=0.515).

Figure5:Thepercentofnitrogen-fixingplantsisposi/velycorrelatedwiththemeanswardheightintheHempsteadPlains,butthecorrela/onisnotsignificant(r=0.063,p=0.582).

Figure6:Thepercentofnitrogen-fixingplantsisnega/velycorrelatedwiththemeanswardheightintheRockySummit,butthecorrela/onnotsignificant(r=-0.036,p=0.747).

MaterialsandMethods(Cont.)Weusedameters/cktomeasure45cmfromthecornerata45degreeangle.Wethenusedthemeters/cktoes/matetheplantheightatfivepointswithineachsubplot.Ateachpointweusedalargenailtomeasurethesoildepth(Aloisio2016).Weusedplantguidestoiden/fyHempsteadPlainsandRockySummitplants,aswellascolonizers.Wevisuallyes/matedtotalcover,speciescover,bareground,anddeadmaterialineachsubplot.

HP 6” RS 6” HP 4” RS 4”