Technical ReportPDF Available

Petition to list the Venus flytrap (Dionaea muscipula Ellis) as Endangered under the 1973 Endangered Species Act

Authors:

Abstract and Figures

The Venus Flytrap (Dionaea muscipula Ellis) is a rare and localized species in the family Droseraceae endemic to wet coastal plain and sandhills habitats in North and South Carolina. Its dramatic specialized aerial snap trap makes it the most widely recognized carnivorous plant in the world. Its trap is a unique evolutionary adaptation shared with only one other species in the world. It is also evolutionarily unique as it is the only species in its genus and alone has an aerial snap trap. Wild populations of the Venus Flytrap are scattered, restricted in geography and suitable habitats, and declining quickly in number and size in response to illegal poaching, development pressures, and the ensuing loss of habitats with appropriate conditions including fire regimes. The Venus Flytrap is nearing extinction in the wild. Only 42 populations exceed a census population size of 500 individuals, and only some of these are fully viable over the longer-term. Together, these populations support less than 2% of this species' original population size. The Endangered Species Act (ESA) states that a species shall be determined to be endangered or threatened based on any of five factors (16 U.S.C. § 1533 (a)(1)). The Venus Flytrap is threatened by at least four of these factors, warranting federal protection. First, it is threatened with significant curtailment of habitat resulting from development, fire suppression, vegetation encroachment, altered hydrology from wetland drainage, and soon sea level rise from climate change. Second, it is threatened directly by overexploitation from poaching and seed collection. Third, existing regulatory mechanisms have failed to protect the species. No habitat supporting larger populations is dedicated specifically to protect flytrap populations. The Venus Flytrap is not formally classified or protected by any federal entity. The decision by the U.S. Fish and Wildlife Service not to list the Venus Flytrap as Threatened or Endangered in 1993 has led to continuing declines in its range and abundance since then. Despite the fact that the Venus Flytrap was listed as a species of Special Concern-Vulnerable in North Carolina in 2010 and that poaching of this species became a felony in 2014, it continues to suffer poaching and population declines. This species is also threatened by other factors including climate change, storm surges, rising sea levels, the loss of genetic variation, and inadequate habitat connectivity, threatening its ability to sustain viable metapopulation dynamics. The Venus Flytrap's geographically restricted range; limited population sizes; isolation of many of its habitats; lack of adequate habitat management in many occupied and potentially suitable habitats; continued losses to these habitats via woody plant encroachment, development, climate change, and rising sea levels; and continued poaching of plants from wild populations all threaten the persistence and viability of this plant species. The magnitude of these threats, their immediacy, and the taxonomic distinctiveness of the Venus Flytrap as the only species in its genus all argue for making the Venus Flytrap a priority for listing as Endangered under the Endangered Species Act.
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Before&the&Secretary&of&the&Interior&
&
Petition&to&list&the&Venus&flytrap&(Dionaea'muscipula&Ellis)&as&
Endangered&under&the&1973&Endangered&Species&Act&
October&21,&2016!
!
Figure&1.!!A!healthy!Venus!Flytrap!individual!growing!in!typically!sandy!soil!and!
open!conditions.!!Photo!courtesty!of!James!Fowler.!
!
Notice&of&Petition&to:&
!
Sally!Jewell,!Secretary!
U.S.!Department!of!the!Interior,!1849!C!Street!NW!Washington,!D.C.!20240!
exsec@ios.doi.gov!
!
Dan!Ashe,!Director!
U.S.!Fish!and!Wildlife!Service,!1849!C!Street!NW!Washington,!D.C.!20240!
Dan_Ashe@fws.gov!
!
Bridget!Fahey,!Chief,!Division!of!Conservation!and!Classification,!!
U.S.!Fish!and!Wildlife!Service,!Endangered!Species!Program,!5275!Leesburg!Pike!Falls!Church,!VA!
22041!
Bridget_Fahey@fws.gov!
!
Cindy!Dohner,!Regional!Director!(Region!4)!
U.S.!Fish!and!Wildlife!Service:!Southeast!Region,!1875!Century!Boulevard,!NE!Suite!400!
Atlanta,!GA!30345!
Cindy_Dohner@fws.gov!
Venus!Flytrap!p.!!
2!
Petitioners:!
James!Affolter!
Professor!of!Horticulture,!University!of!Georgia!
Chair,!Georgia!Plant!Conservation!Alliance!and!Board!of!Directors,!BGCI-US!
!
George!Briggs!
Executive!Director,!The!North!Carolina!Arboretum!
!!and!President,!The!North!Carolina!Arboretum!Society!
!
Kenneth!Cameron!
Professor!of!Botany,!University!of!Wisconsin-Madison,!!
!!and!Director,!Wisconsin!State!Herbarium!
!
Jennifer!Ceska!
Conservation!Coordinator,!State!Botanical!Garden!of!Georgia!
!!and!Georgia!Plant!Conservation!Alliance!
!
Sir!Peter!Crane,!Fellow!Royal!Society!
President,!Oak!Spring!Garden!Foundation,!Upperville,!VA!
Dean,!Yale!School!of!Forestry!&!Environmental!Sciences!(former)!
Director,!Royal!Botanical!Gardens!in!Kew,!London!(former)!
!
Jennifer!Cruse-Sanders!
Vice!President,!Science!&!Conservation,!Atlanta!Botanical!Garden!
!
Robert!Evans!
Natural!Areas!Protection!Manager,!Virginia!Natural!Heritage!Program!
!
Donald!A.!Falk!
Associate!Professor,!University!of!Arizona!
Co-Founder!and!former!Executive!Director,!Center!for!Plant!Conservation!
!
Thomas!Gibson!
205!Danbury!Court!2A,!DeForest,!Wisconsin!
!
Thomas!J.!Givnish!
Henry!Allan!Gleason!Professor!of!Botany,!University!of!Wisconsin-Madison!
!
Kayri!Havens!
Director,!Plant!Science!and!Conservation,!Chicago!Botanical!Garden!
!
Yari!B.!Johnson!
Assistant!Professor!&!Director,!Reclamation,!Environment!&!Conservation!program,!!
!!University!of!Wisconsin-Platteville!
!
Claudia!L.!Jolls!
Associate!Professor,!East!Carolina!University,!Greenville,!NC!!
!
Joyce!Maschinski!
Chief!of!Science,!Center!for!Plant!Conservation!
Venus!Flytrap!p.!!
3!
!!Senior!Scientist,!Institute!for!Conservation!Research,!San!Diego!Zoo!Global!
!
William!F.!Morris!
Professor!of!Biology,!Duke!University,!Durham,!NC!
!
Reed!Noss!
Distinguished!Research!Prof.,!Pegasus!Prof.,!and!Davis-Shine!Prof.!of!Conservation!Biology,!
University!of!Central!Florida!&!President,!Florida!Institute!for!Conservation!Science!
!
Robert!K.!Peet!
Professor!of!Biology,!University!of!North!Carolina,!Chapel!Hill,!NC!
Chair,!Carolina!Vegetation!Survey!
!
John!L.!Randall!
Director!of!Conservation!Programs,!North!Carolina!Botanical!Garden!
!UNC-Chapel!Hill,!Chapel!Hill!NC!27599!
!
Peter!Raven!
President!Emeritus,!Missouri!Botanical!Garden!
!
Kate!Sackman!
Executive!Director,!Botanic!Garden!Conservation!International!US!
!
Casey!Sclar!
Executive!Director,!American!Public!Gardens!Association!
!
John!W.!Terborgh!
James!B.!Duke!Professor!Emeritus,!Duke!University,!Durham,!NC!
!
Damon!Edward!Waitt!
Director,!North!Carolina!Botanical!Garden,!University!of!North!Carolina,!Chapel!Hill,!NC!
!
Donald!M.!Waller!
J.T.!Curtis!Professor!of!Botany!&!Environmental!Studies,!University!of!Wisconsin-Madison!
!
Alan!Weakley!
Director!UNC!Herbarium!and!Adjunct!Associate!Prof.!of!Biology,!!
!!University!of!North!Carolina,!Chapel!Hill,!NC!
!
Peter!S.!White!
Professor!of!Biology,!University!of!North!Carolina,!Chapel!Hill,!NC!
&
& &
Venus!Flytrap!p.!!
4!
Submitted&this&21st&day&of&October,&2016&
!
Pursuant!to!Section!4(b)!of!the!Endangered!Species!Act!(“ESA”),!16!U.S.C.!§!1533(b);!
Section!553(e)!of!the!Administrative!Procedure!Act,!5!U.S.C.!§!553(e);!and!50!C.F.R.!§!
424.14(a),!the!individuals!named!above!hereby!petition!the!Secretary!of!the!Interior,!
through!the!United!States!Fish!and!Wildlife!Service!(USFWS),!to!immediately!protect!the!
Venus!flytrap!(Dionaea'muscipula!Ellis)!as!a!recognized!Endangered!Species!and!to!quickly!
designate!critical!habitat!for!this!plant!species.!!The!USFWS!has!jurisdiction!over!this!
petition.!This!petition!sets!in!motion!a!specific!process,!placing!definite!response!
requirements!on!the!Service.!Specifically,!the!Service!must!issue!an!initial!finding!as!to!
whether!the!petition!“presents!substantial!scientific!or!commercial!information!indicating!
that!the!petitioned!action!may!be!warranted.”!16!U.S.C.!§!1533(b)(3)(A).!USFWS!must!make!
this!initial!finding!“[t]o!the!maximum!extent!practicable,!within!90!days!after!receiving!the!
petition.”!Id.!
!
!
On!behalf!of!the!petitioners,!
! !
Donald!M.!Waller!
!!!! J.T.!Curtis!Professor!of!Botany!&!Environmental!Studies!
! Department!of!Botany!
!University!of!Wisconsin-Madison!
!430!Lincoln!Drive!
!Madison,!WI!!53711!
!
!(608)!698!6495!
!dmwaller@wisc.edu! !
Venus!Flytrap!p.!!
5!
Table&of&Contents&
!
1. Executive!Summary!!!!!!!p.!6!
2. Introduction!!!!!!!!p.!7!
3. The!natural!history,!ecology,!and!genetics!of!Dionaea' ' !p.!8!
3.1. Taxonomy!and!varieties! ! ! !
3.2. Evolutionary!history!!!!!
3.3. Species!description! ! ! !
3.4. Soils!and!climate!!!!!!
3.5. Habitat!needs!and!ties!to!fire!disturbances! ! !
3.6. Reproductive!ecology!!!!!
3.7. Demography!!!!!!
3.8. Population!genetics!!!!!!
4. Geographic!range!and!population!status!!!!!p.!18!
4.1. The!shrinking!range!of!the!Venus!Flytrap!
4.2. Population!surveys!and!locations!
4.3. Record!of!population!declines!
5. Conservation!status!!!!!!!p.!22!
5.1. Past!conservation!actions!
5.2. Current!Regulatory!context!
5.3. Protecting!the!Venus!Flytrap!will!also!protect!other!rare!and!threatened!species!and!
habitat!types!
5.4. Critical!habitat!needs!
5.5. Other!urgent!recovery!actions!needed!
6. Threats!and!criteria!for!listing!!!!!!p.!27!
6.1. Losses!of!habitat!and!range!
6.2. Over-utilization!and!exploitation!
6.3. Disease!and!predation!
6.4. Inadequate!regulatory!protection!
6.5. Other!threats!to!Dionaea!survival!
7. Conclusion!!!!!!!!!p.!34!
8. Literature!cited!!!!!!!!p.!35!!
Venus!Flytrap!p.!!
6!
1.&&Executive&Summary&
The!Venus!Flytrap!(Dionaea'muscipula!Ellis)!is!a!rare!and!localized!species!in!the!family!
Droseraceae!endemic!to!wet!coastal!plain!and!sandhills!habitats!in!North!and!South!
Carolina.!!Its!dramatic!specialized!aerial!snap!trap!makes!it!the!most!widely!recognized!
carnivorous!plant!in!the!world.!Its!trap!is!a!unique!evolutionary!adaptation!shared!with!
only!one!other!species!in!the!world.!!It!is!also!evolutionarily!unique!as!it!is!the!only!species!
in!its!genus!and!alone!has!an!aerial!snap!trap.!!Wild!populations!of!the!Venus!Flytrap!are!
scattered,!restricted!in!geography!and!suitable!habitats,!and!declining!quickly!in!number!
and!size!in!response!to!illegal!poaching,!development!pressures,!and!the!ensuing!loss!of!
habitats!with!appropriate!conditions!including!fire!regimes.!!The!Venus!Flytrap!is!nearing!
extinction!in!the!wild.!!Only!42!populations!exceed!a!census!population!size!of!500!
individuals,!and!only!some!of!these!are!fully!viable!over!the!longer-term.!!Together,!these!
populations!support!less!than!2%!of!this!species'!original!population!size.!!!
!
The!Endangered!Species!Act!(ESA)!states!that!a!species!shall!be!determined!to!be!
endangered!or!threatened!based!on!any!of!five!factors!(16!U.S.C.!§!1533!(a)(1)).!The!Venus!
Flytrap!is!threatened!by!at!least!four&of!these!factors,!warranting!federal!protection.!!First,!
it!is!threatened!with!significant!curtailment&of&habitat!resulting!from!development,!fire!
suppression,!vegetation!encroachment,!altered!hydrology!from!wetland!drainage,!and!soon!
sea!level!rise!from!climate!change.!!Second,!it!is!threatened!directly!by!overexploitation!
from!poaching&and&seed&collection.!!Third,!existing!regulatory&mechanisms!have!failed!
to!protect!the!species.!!No!habitat!supporting!larger!populations!is!dedicated!specifically!to!
protect!flytrap!populations.!!The!Venus!Flytrap!is!not!formally!classified!or!protected!by!
any!federal!entity.!!The!decision!by!the!U.S.!Fish!and!Wildlife!Service!not!to!list!the!Venus!
Flytrap!as!Threatened!or!Endangered!in!1993!has!led!to!continuing!declines!in!its!range!
and!abundance!since!then.!!Despite!the!fact!that!the!Venus!Flytrap!was!listed!as!a!species!of!
Special!Concern-Vulnerable!in!North!Carolina!in!2010!and!that!poaching!of!this!species!
became!a!felony!in!2014,!it!continues!to!suffer!poaching!and!population!declines.!!This!
species!is!also!threatened!by!other&factors&including&climate!change,!storm!surges,!rising!
sea!levels,!the!loss!of!genetic!variation,!and!inadequate!habitat!connectivity,!threatening!its!
ability!to!sustain!viable!metapopulation!dynamics.!!!
!
The!Venus!Flytrap's!geographically!restricted!range;!limited!population!sizes;!isolation!of!
many!of!its!habitats;!lack!of!adequate!habitat!management!in!many!occupied!and!
potentially!suitable!habitats;!continued!losses!to!these!habitats!via!woody!plant!
encroachment,!development,!climate!change,!and!rising!sea!levels;!and!continued!poaching!
of!plants!from!wild!populations!all!threaten!the!persistence!and!viability!of!this!plant!
species.!!The!magnitude!of!these!threats,!their!immediacy,!and!the!taxonomic!
distinctiveness!of!the!Venus!Flytrap!as!the!only!species!in!its!genus!all!argue!for!making!the!
Venus!Flytrap!a!priority!for!listing!as!Endangered!under!the!Endangered!Species!Act.!!!
! !
Venus!Flytrap!p.!!
7!
"It!may!be!counter!intuitive!to!believe!that!a!plant!so!often!sold!in!grocery!
stores!could!be!in!trouble!but!the!Venus!flytrap!truly!is."!
In&Defense&of&Plants&–&http://www.indefenseofplants.com/blog/2015/10/6/the-
plight-of-the-venus-fly-trap&
&&&
2.&&Introduction&
The!Venus!Flytrap!(Dionaea!muscipula!Ellis)!is!probably!the!most!widely!recognized!
carnivorous!plant!in!the!world!(Luken!2005).!!This!iconic!plant!is!alone!in!its!genus,!like!its!
closest!relative,!Aldrovanda!vesiculosa!L.,!also!in!a!monotypic!genus.!!These!species!are!the!
only!descendant!from!a!unique!evolutionary!event!–!the!invention!of!an!active!snap!trap.!!
The!great!improbability!of!this!surprising!trait!has!captivated!the!curiosity!and!attention!of!
people!for!centuries.!!Charles!Darwin!devoted!considerable!attention!to!this!and!other!
carnivorous!plants!because!he!realized!that!showing!how!natural!selection!could!produce!
such!remarkable!and!intricate!adaptations!would!strongly!support!his!theory.!!So!many!are!
beguiled!by!this!plant!and!its!ability!to!suddenly!snap!shut!to!imprison!and!digest!its!prey!
that!this!American!plant!has!become!the!most!widely!recognized!plant!in!the!world.!!This!
popularity!has!also!led!to!great!demand!for!Venus!Flytraps.!!!Commercial!growers!now!
propagate,!distribute,!and!sell!these!plants.!!More!plants!exist!in!captivity!now!than!exist!in!
the!wild!(Evans!et!al.!2012).!!Most!plants!in!private!hands!derive!from!legitimate!sources!
via!propagation.!!However,!market!demand!for!this!species!and!the!lack!of!any!formal!
certification!program!has!also!led!many!to!poach!plants!from!the!wild!for!sale!as!house!or!
medicinal!plants.!!!
Despite!its!popularity,!few!know!that!Venus!Flytraps!are!highly!restricted!geographically.!!
They!only!occur!in!the!Carolina!coastal!plain!with!most!sites!within!90!km!of!Wilmington,!
NC,!from!Beaufort!County!NC!to!Charleston!County!SC!(Mellichamp!2015).!!Even!fewer!are!
aware!of!how!dependent!this!species!is!on!having!suitable!habitats!of!a!very!particular!kind!
available!to!it,!namely!wet!pine!savannas!or!pocosins!that!burn!regularly!or!areas!with!
similar!conditions.!!Many!of!its!populations!have!been!lost!to!habitat!development!or!
conversion,!shifts!in!habitat!conditions,!and!overexploitation!by!plant!collectors.!!Others!
have!been!eliminated!by!shade!and!competition!accompanying!the!loss!of!fire!from!many!
traditional!habitats.!!This!species!is!also!highly!sensitive!to!changes!in!water!levels!as!many!
populations!lie!only!2-4!m!above!sea!level.!!These!forces,!alone!and!collectively,!threaten!
the!continuing!viability!of!remaining!populations!and!thus!survival!of!this!species.!!!
Although!steps!have!been!taken!to!improve!protection!of!certain!habitats!and!populations!
and!to!limit!the!poaching!of!plants!from!wild!populations,!these!efforts!have!not!sufficed!to!
arrest!and!reverse!the!slide!of!this!species!toward!oblivion.!!This!species!therefore!needs!
and!deserves!protection!under!the!U.S.!Endangered!Species!Act!(ESA).!!Without!such!a!
listing,!efforts!to!protect,!sustain,!and!restore!critical!habitat!for!this!species!will!not!be!
systematic,!sustained,!and!comprehensive!enough!to!ensure!survival!of!the!Venus!Flytrap.!!!
Venus!Flytrap!p.!!
8!
In!this!Petition,!we!lay!out!what!is!known!about!this!species'!biology,!ecology,!
biogeography,!and!conservation!in!order!to!document!the!past,!present,!and!future!factors!
that!threaten!this!species.!!This!information!addresses!the!five!criteria!that!the!U.S.!Fish!and!
Wildlife!Service!uses!to!decide!whether!to!add!species!to!the!list!of!federally!threatened!
and!endangered!species.!!In!light!of!the!fact!that!the!Venus!Flytrap!meets!at!least!four!of!
these!five!criteria,!we!argue!that!federal!listing!and!protection!are!immediately!needed!to!
stem!the!strong!historical!declines!observed!in!this!species!and!to!address!the!threats!it!
faces.!!Without!this!listing!and!the!resources!listing!provides,!the!Venus!Flytrap!will!not!be!
protected!effectively!throughout!its!limited!range!on!the!diverse!land-ownership!it!
occupies.!!Because!this!species!faces!substantial!and!immediate!threats!and!represents!the!
unique!member!of!its!genus!and!only!one!of!two!species!in!the!world!equipped!with!the!
snap!trap!adaptation,!the!Venus!Flytrap!should!also!be!given!priority!for!listing!as!an!
endangered!species!under!the!Endangered!Species!Act.!!
Listing!the!Venus!Flytrap!as!federally!Endangered!is!necessary!in!order!to!provide!full!
protection&of&remaining&habitats,!resources!and!incentives!to!actively&manage&
remaining&habitats,!and!opportunities!and!incentives!to!actively!restore&additional&
habitats&and&populations!in!locations!that!are!suitable!for!this!species!but!currently!
unoccupied.!!In!particular,!ESA!listing!would!ensure!analyses!and!planning!to!promote!
adequate!habitat!and!suitable!conditions!to!sustain!and!restore!flytrap!populations!
throughout!its!former!range.!!It!would!also!allow!forward!planning!to!identify!potentially!
suitable!habitats!based!on!projections!of!how!the!range!of!the!Venus!Flytrap!will!likely!shift!
under!projected!future!changes!in!land!use,!water!levels,!and!climate.!
!
3. The&natural&history&and&ecology&of&Dionaea&
3.1. &Taxonomy&and&varieties&
Dionaea!muscipula!is!a!carnivorous!plant!endemic!to!the!U.S.!!Dionaea!is!a!monotypic!genus!
of!plant!nested!within!the!Droseraceae,!a!small!family!of!180!carnivorous!plants!located!in!
the!order!Caryophyllales!(Weakley!2015).!!The!Taxonomic!Serial!Number!for!Dionaea'
muscipula!is!22008.!!There!are!only!three!genera!in!the!Droseraceae:!!Drosera,!Dionaea!and!
Aldrovanda,!with!the!latter!two!being!monotypic!in!having!only!one!species!each.!!These!
two!genera!also!share!the!derived!trait!of!having!snap-traps,!representing!a!unique!
evolutionary!event!(Cameron!et!al.!2002).!!Aldrovandra!vesiculosa!(the!waterwheel!plant)!
shares!snap-traps!with!Dionaea,!but!its!traps!are!smaller!and!underwater,!being!an!aquatic!
plant.!!Droseraceae!are!sister!to!a!clade!consisting!almost!exclusively!of!other!carnivorous!
plants,!including!Drosophyllaceae!(monotypic!Drosophyllum,!a!fly-paper!plant!not!unlike!
Drosera!from!the!western!Mediterranean),!Nepenthaceae!(Nepenthes,!with!ca.!135!species,!
the!tropical!pitcher!plants!from!SE!Asia!to!Madagascar),!and!Dioncophyllaceae!(monotypic!
Triphyophyllum!from!West!Africa,!a!“part-time”!carnivorous!plant!that!has!sticky!leaves!
while!a!juvenile!rain-forest!vine,!plus!non-carnivorous!Dioncophyllum)!(Cameron!et!al.!
2002).!
Venus!Flytrap!p.!!
9!
The!common!name!of!Dionaea!refers!to!Venus,!the!Roman!goddess!of!love.!The!genus!
name,!Dionaea!("daughter!of!Dione"),!refers!to!the!Greek!goddess!Aphrodite,!while!the!
species!name,!muscipula,!is!Latin!for!"mousetrap",!reflecting!its!unique!snap-trap!
(Wikipedia!2016).!!In!2005,!the!Venus!Flytrap!was!adopted!as!the!official!State!Carnivorous!
Plant!of!North!Carolina!(http://ncpedia.org/symbols/carnivorousplant).!
There!are!28!registered!cultivars!of!Dionaea!(Schlauer!2016,!Carnivorous!Plant!Database;!
https://www.flytrapcare.com/venus-fly-trap-cultivated-variety-list).!!Many!of!these!
genetic!variants!are!propagated!vegetatively!(asexually)!via!offshoots!or!tissue!culture!for!
sale!as!houseplants.!!Many!vendors!now!offer!flytraps!from!a!variety!of!sources,!making!it!
difficult!to!trace!whether!these!are!legitimate!and!sustainable!or!derived!from!poached!
plants.!!!
3.2. &Evolutionary&history&
Although!plant!carnivory!exists!in!at!least!3!orders!of!higher!plants,!within!the!order!
Caryophyllales,!genetic!and!fossil!evidence!suggest!that!carnivory!evolved!from!one!
common!ancestor!(Cameron!et!al.!2002),!an!origin!currently!dated!at!76!million!years!ago!
(Zanne!et!al.!2013).!!(See!tree!at:!
http://www.onezoom.org/OneZoom/static/OZLegacy/vascularplants_tank2013nature.htm).!!The!
Venus!Flytrap!represents!an!independent!evolutionary!lineage!with!a!unique!adaptation!–!
active!snap!traps!–!that!make!it!the!most!famous!and!emblematic!carnivorous!plant!in!the!
world.!!DNA!sequence!data!confirm!that!Dionaea'and'Aldrovanda!are!sister!genera!that!
diverged!from!each!other!roughly!51!million!years!ago!(Zanne!et!al.!2013)!and!together!are!
the!closest!relatives!of!the!sundews!(Drosera)!in!the!family!Droseraceae!(Cameron!et!al.!
2002).!!This!confirms!that!snap!traps!only!evolved!once!in!the!history!of!plants!–!from!
flypaper-traps!like!those!in!present-day!Drosera,'Drosophyllum,!and!Triphyophyllum.!!Given!
contemporary!distributions,!ancestors!of!Dionaea!presumably!migrated!to!the!Americas!
but!then!diminished!in!range!over!time!to!only!occupy!the!Carolina!coastal!plain!and!
Sandhills.!!Both!genera!are!now!monotypic!with!just!one!surviving!species.!!Dionaea!is!thus!
taxonomically!distinct,!justifying!priority!consideration!for!listing.!
Among!terrestrial!plants,!Dionaea!is!unique!in!having!rapidly!closing!snap!traps.!!This!trait!
evolved!via!several!successive!steps!that!involved!evolving!sensitivity!to!the!presence!of!
prey,!rapid!nerve-like!signal!transmission,!curling!leaf!movements!to!encircle!and!digest!
prey!and!eventually!a!hinge!to!close!around!and!imprison!trapped!prey!(Gibson!&!Waller!
2009).!!These!adaptations!include!tentacles!(common!in!Drosera)!becoming!modified!into!
trigger!hairs!and!marginal!‘teeth’,!sticky!tentacles!being!lost,!digestive!glands!becoming!
depressed,!and!leaf!movements!evolving!to!become!rapid.!!The!snap!trap!itself!may!be!an!
adaptation!to!snare!larger!prey!that!might!otherwise!tear!away!from!sticky!leaves!and!
encapsulate!them!in!a!protected!chamber!from!which!few!nutrients!are!lost.!!Their!ability!
to!trap!larger!prey!and!digest!them!efficiently!for!nutrients!provides!an!advantage!in!terms!
of!growth!and!reproduction!in!their!wet,!open,!and!highly!nutrient!deficient!sandy!soil!
habitats.!!
Their!special!adaptations!have!made!Venus!Flytraps!of!great!interest!to!scientists!since!the!
days!of!Charles!Darwin.!!New!and!innovative!papers!continue!to!be!published!on!this!
Venus!Flytrap!p.!!
10!
species!on!their!evolutionary!history!and!relationships,!physiology,!leaf!mechanics,!and!the!
biochemical!mechanisms!that!allow!them!to!propagate!and!respond!to!bio-electric!signals!
so!rapidly.!!!
3.3. &Species&Description&
Several!descriptions!of!Dionaea'muscipula!exist!including!this!one!in!Godfrey!and!Wooten!
(1981):!
Perennial!carnivorous!herb!with!leaves!closely!set!on!a!short!stem,!the!petiolar!
bases!dilated!and!closely!overlapping!so!that!the!short!stem!appears!somewhat!
bulbous.!Leaf!blades!hinged!lengthwise!in!the!middle,!each!of!the!two!halves!nearly!
kidney-shaped,!the!margin!of!each!equipped!with!conspicuous!bristles!which!
interlock!when!the!leaf!is!closed;!petiole!usually!markedly!winged!and!expanded!
distally.!Inflorescence!scapose,!1-3!dm!tall,!umbeliform-cymose.!Sepals!5.!Petals!5,!
white,!spatulate,!about!12!mm!long.!Stamens!15!(10-20).!Ovary!superior,!1-locular,!
style!1,!stigma!with!numerous!elongate!papillae.!Capsule!ovoid.!Seeds!numerous,!
black!and!shiny,!obovoid,!tiny.!
and!this!one!based!on!Wikipedia's!description:!
The!Venus!flytrap!is!a!small!plant!whose!structure!consists!of!a!rosette!of!four!to!
seven!leaves!arising!from!a!short!subterranean!stem!that!is!actually!a!bulb-like!
object.!Each!stem!reaches!a!maximum!size!of!3-10!cm,!depending!on!the!time!of!year!
(Rice!2007);!longer!leaves!with!robust!traps!are!usually!formed!after!flowering.!
Flytraps!that!have!more!than!7!leaves!are!colonies!formed!by!rosettes!that!have!
divided!beneath!the!ground.!
The!leaf!blade!is!divided!into!two!regions:!!a!flat,!heart-shaped!photosynthesis-
capable!petiole,!and!a!pair!of!terminal!lobes!hinged!at!the!midrib,!forming!the!trap!
which!is!the!true!leaf.!The!upper!surface!of!these!lobes!contains!red!
anthocyanin!pigments!and!its!edges!secrete!mucilage.!The!lobes!exhibit!rapid!plant!
movements,!snapping!shut!when!stimulated!by!prey.!The!trapping!mechanism!is!
tripped!when!prey!contacts!one!of!the!three!hair-like!trichomes!that!are!found!on!
the!upper!surface!of!each!of!the!lobes.!The!mechanism!is!so!highly!specialized!that!it!
can!distinguish!between!living!prey!and!non-prey!stimuli,!such!as!falling!raindrops;!
two!trigger!hairs!must!be!touched!in!succession!within!20!seconds!of!each!other!or!
one!hair!touched!twice!in!rapid!succession,!whereupon!the!lobes!of!the!trap!will!
snap!shut,!typically!in!about!one-tenth!of!a!second.!!The!edges!of!the!lobes!are!
fringed!by!stiff!hair-like!protrusions!or!cilia,!which!mesh!together!and!prevent!large!
prey!from!escaping.!These!protrusions,!and!the!trigger!hairs!(also!known!as!
sensitive!hairs)!are!likely!homologous!with!the!tentacles!found!in!this!plant’s!close!
relatives,!the!sundews.!Scientists!have!concluded!that!the!snap!trap!evolved!from!a!
fly-paper!trap!similar!to!that!of!Drosera!(Cameron!et!al.!2002).!
3.4. &Soils&and&climate&
Venus!Flytrap!p.!!
11!
Soils!–!The!Venus!Flytrap!only!occurs!in!nitrogen!and!phosphorus-poor!environments,!such!
as!bogs,!pocosins,!and!wet!savannas.!!It!is!restricted!to!wet!sandy!and!peaty!soils!–!
particular!conditions!that!maintain!both!hydration!and!nutrient!scarcity.!!Because!the!
lower!Coastal!Plain!of!the!Carolinas!is!flat,!losing!<1m!in!elevation!every!10!km,!it!has!an!
abundance!of!habitats!with!wet,!poorly!drained!soils.!!These!result!in!numerous!expanses!
of!wetlands!interspersed!with!ancient!beach!dunes!and!other!areas!of!sandy!soil.!!The!
resulting!soils!of!the!Coastal!Plain!are!often!sandy!or!mucky!perched!2+m!above!an!
impermeable!layer.!!!The!parent!material!here!is!generally!unconsolidated!coastal!plain!
sediment!deposited!in!the!last!80,000!years!(Daniels!et!al.1999;!Soil!Survey!Staff!2016).!!In!
addition,!excellent!Flytrap!habitats!exist!in!areas!of!slightly!higher!topography!(10-20m)!on!
the!coastal!plain!in!SE!North!Carolina!on!the!Lake!Wales!Ridge!(R.!Peet,!pers.!commun.).!
!
Typical!soil!series!in!the!middle!and!lower!Coastal!Plain!include!Baymeade!(Arenic!
Hapludults),!Blaney!(Arenic!Hapludults),!Foreston!(Aquic!Paleudults),!Grifton!(Typic!
Orchraqualfs),!Johnston!(Cumulic!Humaquepts),!Kureb!(Spodic!Quartzipsamments),!Leon!
(Aeric!Haplaquods),!Murville!(Typic!Haplaquods),!Onslow!(Spodic!Paleudults),!Pactolus!
(Aquic!Quartzipsamments),!and!Woodington!(Typic!Paleaquults).!!While!typical!soils!in!the!
upper!Coastal!Plain!include!Blaney!(Arenic!Hapludults),!Gilead!(Aquic!Hapludults),!Rains!
(Typic!Paleaquults)!and!Woodington!(Typic!Paleaquults).!!!
The!soils!that!support!Dionaea!are!typically!damp!to!wet!and!low!to!very!low!in!nutrients!
and!particularly!phosphorus.!!An!unresolved!question!concerns!the!degree!to!which!
aerially!deposited!nitrogen!compounds!(or!other!nutrients)!might!currently!threaten!
Dionaea!by!accelerating!the!growth!of!competing!non-carnivorous!plants,!allowing!them!to!
overtop!and!suppress!the!growth!of!Dionaea!(see!section!6.5).!!!This!potential!nutrient!
enrichment!effect!makes!maintaining!adequately!frequent!fires!(which!volatilize!nitrogen)!
even!more!important!(see!section!3.5).!!Fertilization!experiments,!however,!suggest!that!
Dionaea!responds!much!more!to!phosphorus!than!to!nitrogen!(R.!Peet,!pers.!commun.)!
Climate&–&The!Coastal!Plain!of!the!Carolinas!has!a!humid-subtropical!climate.!!Over!the!30-
year!period!from!1971!to!2000,!the!average!annual!temperature!varied!from!17.7°C!in!the!
lower!Coastal!Plain!to!16.2°C!in!the!upper!Coastal!Plain.!!Average!daily!maximum!
temperature!was!24.2°C!in!the!lower!Coastal!Plain!and!22.6°C!in!the!upper!Coastal!Plain,!
while!the!average!daily!minimum!temperature!was!11.1°C!and!9.9°C,!respectively.!!!The!
mean!annual!precipitation!ranges!from!1140–1650!mm!per!year,!with!less!precipitation!
falling!in!the!Sandhills!and!more!in!the!lower!Coastal!Plain!(State!Climate!Office!of!NC).!
3.5. Habitat&needs&and&ties&to&fire&disturbances&
The!Venus!Flytrap!is!a!habitat!specialist!adapted!to!highly!particular!habitat!conditions!that!
continue!to!lose!key!characteristics!in!many!areas!and!have!diminished!greatly!in!extent.!!
As!with!most!carnivorous!plants,!it!grows!in!habitats!that!are!sunny,!moist,!and!nutrient-
poor,!where!it!is!likely!to!have!a!growth!advantage!over!non-carnivores!(Givnish!et!al.!
1984;!Givnish!1989).!!The!Venus!Flytrap!inhabits!flat,!damp!to!wet,!and!open!to!semi-open!
habitats!in!the!coastal!plains!of!southeast!North!Carolina!and!a!small!area!in!northeastern!
South!Carolina,!usually!on!sandy!nutrient-poor!substrates!often!of!low!pH!(see!Soils!above).!!
In!the!lower!Coastal!Plain!of!North!Carolina,!most!plants!occur!in!wet!pine!savannas!or!wet!
Venus!Flytrap!p.!!
12!
pine!flatwoods,!typically!occurring!in!ecotonal!areas!midway!along!a!moisture!gradient!that!
spans!pocosin!shrublands!on!the!wetter!end!to!mesic!to!xeric!pine!savannas!on!the!drier!
end!(Roberts!and!Oosting!1958;!Thornhill!et!al.!2014).!!They!are!also!occasionally!found!at!
the!ecotone!between!Carolina!bays!and!adjacent!plant!communities.!!In!the!middle!and!
upper!Coastal!Plain!they!occur!on!the!narrow!ecotones!around!Carolina!Bays,!streamhead!
pocosins!(linear,!evergreen!shrub!bogs!along!small!creeks!and!their!headwaters!-!
NatureServe!2015),!and!sandhill!seeps.!!In!South!Carolina,!small!populations!of!the!species!
occur!primarily!at!the!ecotone!between!Carolina!bays!and!adjacent!plant!communities!in!
Horry!&!Georgetown!Counties!(Luken!2005).!!Because!these!communities!are!maintained!
by!regular!fires,!retaining!them!will!require!us!to!apply!regular!burning.!
The!habitat!specificity!of!the!Venus!Flytrap!also!reflects!its!association!with!particular!
micro-sites!and!transitional!environmental!conditions!(ecotones).!!The!ecotones!that!
flytraps!usually!occupy!can!be!quite!narrow.!!In!areas!near!Boiling!Spring!Lakes,!NC,!the!
elevation!can!change!dramatically!(up!to!2m)!over!short!distances!(<100!m)!from!xeric!
longleaf!pine-turkey!oak!savannas!to!lakes!surrounded!by!pocosin!shrubs.!!Here,!the!Venus!
Flytrap!occurs!across!a!narrow!4!m!band!where!the!most!suitable!moisture!regime!exists.!!
If!water!tables!shift,!e.g.,!in!response!to!drought,!fire,!or!increased!rainfall,!Venus!Flytrap!
populations!must!follow.!!For!example,!flytraps!often!die!at!drier!ends!of!soil!moister!
gradients,!restricting!their!distribution!to!pocosin!ecotones.!!The!pocosin!itself!is!usually!
too!thick!with!plants!to!support!flytraps,!but!occasional!flytraps!can!be!found!perched!on!
rotting,!sphagnum-covered!stumps!further!into!the!shrubs!where!wetter!conditions!
prevail.!!This!illustrates!the!importance!of!micro-topography!to!this!species!and!how!much!
it!depends!on!particular!moisture!conditions.!!In!another!area!(now!protected!as!a!
conservation!preserve),!30-year-old!tire!tracks!from!off-road!vehicles!created!microsites!
for!flytrap!habitat.!!Where!conditions!are!slightly!dryer,!flytraps!occur!in!the!ruts!where!
wetter!conditions!prevail!than!in!adjacent!soils.!!In!contrast,!in!wetter!conditions,!flytraps!
instead!occur!on!adjacent!soils!next!to,!but!not!in,!the!ruts.!!The!existence!of!local!
vegetation!continua!with!subtle!yet!crucial!shifts!in!structure!help!ensure!that!local!
conditions!suitable!for!the!Venus!Flytrap!remain!even!as!the!locations!of!patches!of!suitable!
habitat!shift!with!changing!precipitation,!temperature,!fire,!and!succession.!
Habitats!that!support!Dionaea!are!often!insular,!with!plants!restricted!to!narrow!ecotones!
that!burn!regularly.!!Kologiski!(1977)!quantified!the!microhabitat!of!the!flytrap!in!his!
classification!of!the!vegetation!types!of!the!Green!Swamp,!North!Carolina.!!He!found!that!
the!plant!is!restricted!to!community!types!that!are!both!wet!and!burn!frequently!(Kologiski!
Appendix!II).!!He!notes!that!flytraps!often!occur!at!0-1%!cover,!but!in!2!stands!(147!and!
148),!flytraps!occurred!at!1-10%!cover!suggesting!ideal!conditions.!!Although!Flytraps!
occur!in!11!of!~100!plant!community!types!(as!defined!by!the!U.S.!National!Vegetation!
Classification,!Carolina!Vegetation!Survey!data!-!http://cvs.bio.unc.edu/),!all!these!reflect!
these!same!moist,!infertile,!open,!and!fire-maintained!conditions!(R.!Peet,!pers.!commun.).!
Ecotone!habitats!suitable!for!Dionaea!were!once!(pre!1850)!common!in!wet!longleaf!pine!
savannas,!allowing!it!to!become!very!abundant!in!this!ecosystem!that!occurred!commonly!
in!southeastern!North!Carolina!and,!to!a!much!lesser!extent,!in!northeastern!South!
Carolina.!!This!is!reflected!in!several!quotes.!!In!1783,!Young!states!(Coker!1928,!p.!221):!“I!
found!this!in!great!abundance!in!North!Carolina!and!in!some!parts!of!South!Carolina!…”!!
Venus!Flytrap!p.!!
13!
Coker!(1928)!himself!wrote!that!“In!Hanover!and!Brunswick!Counties!.!.!!the!plants!are!so!
widely!distributed!and!so!abundant!that!they!remain!by!the!millions,!although!many!of!
their!stations!have!been!destroyed…”!!Even!in!the!1970s,!Kologiski!(1977,!p.!79)!wrote!that!
the!flytrap!“is!found!throughout!the!savannas!in!great!abundance.”!!The!loss!of!the!flytrap’s!
natural!ecotonal!habitats,!however,!has!increased!greatly!since!then.!!In!order!to!preserve!
the!matrix!of!wet!Longleaf!Pine!Savannas!where!flytraps!generally!occur,!these!habitats!
deserve!critical!habitat!designation.!
Plant!cover!in!Dionaea!zones!is!generally!sparse!with!some!grasses,!herbs,!and!sphagnum!
but!also!bare!patches!between!plants!(Roberts!&!Oosting!1958).!!This!generally!reflects!the!
effects!of!regular!burning.!!Dionaea!populations!appear!to!thrive!under!fire!regimes!where!
fires!recur!at!least!every!3-5!years!(Schnell!et!al.!2000;!Luken!2005;!Evans!et!al.!2012).!!
Longer!fire!intervals!are!associated!with!rapid!population!declines.!!Thus,!for!populations!
of!Dionaea!to!thrive!and!persist,!fires!must!recur!regularly!and!persistently.!!Sites!without!a!
long!history!of!frequent!fires!rarely!support!Dionaea.!!In!contrast,!local!plants!can!persist!a!
long!time!if!the!site!burns!frequently.!!In!the!Green!Swamp,!Dionaea!declined!greatly!after!
the!Nature!Conservancy!replaced!annual!burns!with!a!3-4!year!interval!between!burns!
(Palmquist!et!al.!2014).!!Frost!2000!concludes!that!Dionaea!is!"only!found!on!the!most!fire-
exposed!areas!of!the!landscape.”!
The'dependence!of!Dionaea!on!fire!reflects!two!key!facts.!!First,!this!plant!is!a!poor!
competitor!for!space!against!more!conventional!plants!in!crowded!circumstances!as!it!is!
short!and!its!leaves!are!arranged!in!a!flat!rosette.!!In!microsites!with!abundant!plant!cover,!
taller!species!overtop!and!outcompete!Dionaea!by!shading!it!and!burying!its!leaves!in!leaf!
litter.!!Taller!surrounding!plants!may!also!reduce!the!ability!of!flytraps!to!catch!larger!
insect!prey!(Schulze!et!al.!2001)!or!to!benefit!photosynthetically!from!the!nutrients!
obtained!from!such!prey!(Givnish!et!al.!1984).!!Fires!remove!most!of!these!competitors!and!
the!leaf!litter,!promoting!flytrap!growth,!flowering,!and!seed!production.!!Fires!also!provide!
the!bare!mineral!soil!conditions!that!promote!seedling!germination!and!establishment.!!
Second,!recurrent!fire!and!flooding!disturbances!regularly!kill!plants!and!may!eliminate!
populations.!!This!makes!Dionaea!reliant!on!seed!production!and!dispersal!to!suitable!safe!
sites!to!sustain!its!populations.!!Given!that!its!required!micro-habitat!patches!are!scattered!
and!often!small,!its!seeds!must!disperse!in!sufficient!numbers!to!regularly!colonize!and!
recolonize!these!patches.!!In!other!words,!this!species!necessarily!relies!on!meta-
population!dynamics!and!can!only!persist!in!areas!that!sustain!many!suitable!habitat!
patches!in!close!proximity!with!fires!frequent!enough!to!maintain!these!conditions!–!but!
not!so!prevalent!that!all!such!patches!are!burned!simultaneously.!!A!corollary!is!that!the!
persistence!of!Dionaea!sub-populations!requires!regular!and!adequate!seed!production!and!
dispersal!to!these!suitable,!but!evanescent,!habitat!patches.!
In!summary,!lack!of!regular!fires!and!competition!from!taller!plants!are!the!two!and!
interrelated!major!factors!acting!to!limit!the!numbers!and!persistence!of!Dionaea!within!its!
wet!longleaf!pine!savanna!habitats!(though!hydrology!also!plays!a!role,!as!described!
below).!!The!persistence!of!Venus!Flytrap!populations!thus!depends!critically!on!having!
adequate!soil!moisture,!low!nutrient!conditions,!sparse!woody!plant!cover,!and!the!regular!
fires!that!reduce!taller!plant!cover,!oxidize!nitrogen,!and!expose!mineral!(sandy)!soils.!!In!
the!absence!of!these!effects,!competing!vegetation!grows!quickly!to!shade!and!suppress!
Venus!Flytrap!p.!!
14!
flytrap!individuals,!first!suppressing!flowering,!fruiting,!and!growth,!then!killing!the!plants.!!
It!is!thus!necessary!to!maintain!the!more!open,!high!light,!and!low-nutrient!conditions!that!
this!species!requires.!!Without!fires,!shrubs!quickly!overtake!the!narrow!ecotonal!bands!
where!Venus!Flytrap!thrives,!eliminating!its!habitats.!!!
3.6. Reproductive&ecology&
Flowering'and'Pollination!–!There!is!little!published!about!the!pollination!of!Venus!Flytraps!
and!no!documentation!on!what!insects!regularly!or!successfully!pollinate!this!plant!
(Randall!&!Kunz!2016).!!A!search!of!350+!articles!listed!in!Google!Scholar!revealed!none!
that!mentioned!which!species!pollinate!this!rare!plant.!!Roberts!and!Oosting!(1958)!did!
report!that!the!species!is!“entomophilous,!apparently!by!various!beetles,!small!flies!and!
possibly!spiders,!all!of!which!may!be!seen!in!the!flowers.”!!The!flowers!are!about!10-20!cm!
above!the!leaves!and!snap!traps!so!insects!pollinating!the!flowers!do!not!get!trapped.!Venus!
Flytrap!also!exhibits!temporal!separation!of!traps!and!flowers;!it!temporarily!suspends!
production!of!new!trap!leaves!during!flowering!(Roberts!&!Oosting!1958).!!
Seed'set!–!We!found!little!information!about!how!environmental!conditions,!plant!size,!or!
previous!reproductive!activity!affect!patterns!of!seed!set!in!Dionaea!(but!see!Section!3.7).!
We!also!could!not!find!information!on!the!regularity!of!seed!set.!!No!studies!we!are!aware!
of!document!how!far!seeds!disperse!or!the!rates!at!which!they!colonize!sites!and!
successfully!germinate!in!nature.!!Such!studies!are!not!simple!but!are!greatly!needed!if!we!
are!to!gauge!how!far!populations!can!be!from!each!other!and!still!allow!reciprocal!
recolonization!and!population!persistence.!!Given!that!the!frequency!of!such!colonization!
events!will!depend!on!the!seed!rain,!it!also!behooves!us!to!learn!more!about!how!variation!
in!seed!set!may!influence!local!colonization!dynamics.!
Seedling'establishment!–!Venus!Flytrap!seeds!are!reported!to!germinate!either!immediately!
after!dropping!from!the!fruits!with!no!apparent!dormancy!(W.!Morris,!Duke!University,!
pers.!commun.)!or!later!during!the!cool!season!(R.!Peet,!pers.!observ.).!!This!means!that!
good!years!for!seed!production!cannot!serve!to!sustain!recruitment!in!later!years!–!except!
by!allowing!more!plants!to!establish.!!Local!recruitment!and!population!persistence!thus!
depend!critically!on!maintaining!mature!reproductive!individuals.!Gibson!(2016)!further!
noted!situations!where!seedlings!establish!in!patches!of!bare!sand!being!invaded!by!
sphagnum!mosses!(also!see!Luken!2005).!!Larger!adult!plants!appear!to!grow!in!drier!sand!
without!much!sphagnum!moss.!!Their!local!distribution!may!result!from!high!seedling!
mortality!during!periods!of!drought.!!Adult!flytraps!appear!to!survive!such!periods!much!
better,!reflecting!their!deeper!roots!or!the!water!they!can!store!in!their!rhizomes.!
Further!work!is!clearly!needed!to!learn!more!about!how!patterns!of!flowering,!pollination,!
seed!set,!and!seedling!and!population!establishment!in!the!Venus!Flytrap!affect!local!and!
regional!population!dynamics.!!
3.7. &Demography&
It!is!surprising!to!realize!that!the!Venus!Flytrap,!a!plant!known!around!the!world!that!has!
been!studied!for!two!centuries,!lacks!any!comprehensive!demographic!study!of!natural!
populations.!!No!such!studies!have!been!published.!!Quantifying!the!fundamental!
Venus!Flytrap!p.!!
15!
demographic!processes!of!survival,!growth,!seed!production,!and!the!recruitment!of!new!
plants!is!clearly!necessary!if!we!are!to!understand!how!populations!persist!in!the!wild,!how!
particular!habitat!or!landscape!conditions!threaten!population!persistence,!and!how!best!to!
manage!those!threats.!!We!do!know!from!propagation!studies!that!growers!can!produce!
flowering!plants!in!three!years.!!Without!prey,!plants!would!need!longer!(e.g.,!five!years)!
!
Despite!the!lack!of!comprehensive!studies!of!Flytrap!demography,!a!few!studies!exist!that!
describe!key!demographic!processes!in!Venus!Flytrap!populations!and!how!these!appear!to!
relate!to!threats!such!as!fire!suppression!and!climate!change.!!For!example,!Roberts!and!
Oosting!(1958)!reported!the!results!of!a!field!experiment!in!which!they!translocated!plants!
into!uncleared!and!cleared!plots!to!which!ash!(a!potential!source!of!nutrients)!had!been!
added!(or!not).!!They!reported!that!removing!competitors!and!adding!ash!(both!
consequences!of!fires)!increased!the!probability!of!flowering.!!They!also!report!that!seeds!
rapidly!lose!viability!at!room!temperature!in!the!laboratory,!with!less!than!2%!of!seeds!
germinating!after!only!100!days!of!storage.!!Beyond!this!study,!we!know!of!no!published!
estimates!of!rates!of!fruit!production,!growth,!or!multi-year!survival!within!natural!
populations.!!Estimates!of!all!these!are!needed!to!understand!how!local!populations!persist.!!!
!
!
&
Figure&2.!!Photographs!and!description!of!the!demographic!monitoring!of!six!
Venus!Flytrap!populations!initiated!by!Dr.!W.!Morris!in!2015.!!Photos!by!Elsita!
Kiekebusch,!North!Carolina!State!University.!
!
Fortunately,!more!comprehensive!demographic!studies!are!now!underway.!!Starting!in!
2015,!the!laboratory!of!Dr.!William!Morris!at!Duke!University!(with!funding!from!the!
Demography+studies:+6+popula4ons+
across+range+(so+far)+
+
Also+monitoring:+
+-+soil+temperature+
+-+soil+moisture+
+-+all+soil+nutrients+
Venus!Flytrap!p.!!
16!
Strategic!Environmental!Research!and!Development!Program!at!the!Department!of!
Defense)!began!a!demographic!study!of!six!populations!of!Venus!Flytrap!in!North!Carolina!
(Fig.!2).!!Two!of!these!are!in!the!Croatan!National!Forest,!two!are!at!Camp!Lejeune!Marine!
Base,!and!two!at!the!Ft.!Bragg!Army!Base.!The!first!annual!re-census!of!these!populations!
took!place!in!2016.!!All!demographic!rates!(survival!of!individuals!by!size,!growth!in!size!
from!year!to!year,!seed!production,!and!recruitment!of!new!individuals!from!seeds)!are!
now!being!quantified!for!each!population.!!This!study!is!also!measuring!environmental!
variables!that!may!affect!these!rates!in!every!population.!!These!include!soil!temperature,!
soil!moisture,!and!soil!nutrient!levels.!!The!populations!being!monitored!were!chosen!to!
span!a!range!of!time!since!the!last!fire!with!two!of!the!populations!experiencing!fires!since!
the!study!began.!!This!study!will!also!complement!and!extend!the!clearing!and!ash-addition!
experiment!of!Roberts!and!Oosting!(1958)!by!repeating!their!experiment!at!two!sites!and!
tracking!the!ensuing!demographic!responses!(of!all!rates,!not!just!flowering!probability).!!
Finally,!these!investigators!are!also!planning!experimental!burns!at!Ft.!Bragg,!as!well!as!
greenhouse!experiments!to!quantify!the!impacts!of!changes!in!soil!moisture,!soil!nutrients,!
and!prey!availability!on!flytrap!growth.!!!
!
As!these!studies!were!initiated!just!over!a!year!ago,!no!results!have!yet!been!published.!!
Nevertheless,!these!studies!complement!this!Petition!and!should!be!of!great!value!to!the!
U.S.!Fish!&!Wildlife!Service!in!providing!key!data!to!assess!population!growth!and!viability!
and!the!effects!of!management!activities!on!local!population!dynamics!and!resilience.!!The!
data!they!generate!can!eventually!be!used!to!parameterize!population!models!that!will!
allow!us!to!understand!and!predict!how!climate!change!and!changes!in!fire!frequency!will!
affect!flytrap!populations!into!the!future.!!These!models!will!provide!a!useful!summary!of!
population!dynamics.!!They!will!also!help!guide!management,!e.g.,!by!allowing!us!to!
determine!optimal!fire!frequencies.!!These!results!should!be!of!great!use!to!the!USFWS!for!
efficiently!crafting!an!effective!Recovery!Plan!once!the!species!is!listed!under!ESA.!!!
!
!
!
Venus!Flytrap!p.!!
17!
Figure&3.!!Distributions!of!plant!sizes!and!the!relationship!between!plant!size!
and!fruit!production!as!observed!in!the!six!populations!in!North!Carolina!
whose!demographic!behavior!is!being!tracked!(W.!Morris,!unpublished!data).!!
!
Size!distributions!in!many!populations!follow!the!classic!J-shape!expected!in!populations!
experiencing!high!attrition!as!seedlings!mature!to!larger!size!classes!(top!row,!Fig.!3).!!
However,!we!also!see!individual!populations!at!both!Fort!Bragg!and!Camp!LeJeune!that!
show!substantially!higher!rates!of!apparent!recruitment!to!larger!plant!sizes!(assuming!we!
can!interpret!this!static!pattern!as!reflecting!a!dynamic!pattern!through!time).!!Over!time,!
this!study!should!allow!us!to!determine!the!conditions!that!may!be!favoring!this!higher!
recruitment.!In!the!lower!row!of!Figure!3,!we!see!the!relationship!between!size!and!fruit!
production!from!the!2015!census!of!the!six!populations.!!Again,!we!see!variation!among!
populations!in!their!size-dependent!fruit!production.!!This!further!suggests!that!differences!
among!sites!in!environmental!conditions!are!having!demographic!effects.!!While!plants!
must!reach!a!minimum!size!in!order!to!fruit,!fruit!production!appears!not!to!increase!with!
size!once!that!size!threshold!for!fruiting!has!been!reached.!!Two!of!the!size!histograms!
show!an!under-representation!of!small!plants!(where!the!histogram!is!unimodal);!these!are!
long-unburned!sites!where!competition!is!intense,!fruit!production!is!relatively!low,!and!
recruitment!of!new,!small!plants!into!the!populations!is!correspondingly!depressed.!
!
At!a!broader!geographic!scale,!we!expect!individual!local!Venus!Flytrap!populations!to!exist!
within!the!context!of!meta-population!dynamics.!!As!noted!above,!the!microhabitat!patches!
that!Venus!Flytrap!plants!require!are!scattered,!sometimes!small,!and!regularly!affected!by!
fluctuations!in!the!water!table!and!the!time!since!fire!(limiting!the!growth!of!taller!plants).!!
This!requires!that!Flytrap!seeds!disperse!in!sufficient!numbers!to!effectively!colonize!and!
recolonize!newly!available!patches!of!suitable!habitat.!!Thus,!for!populations!of!this!species!
to!persist!in!a!given!habitat,!it!must!grow!large!enough!to!flower!in!a!relatively!short!period!
of!time,!flower,!produce!seeds!from!those!flowers,!and!disperse!those!seeds!to!other!
suitable!microsites!–!all!before!local!plants!lose!adequate!water!or!are!overtopped!by!
competing!plants.!!The!Venus!Flytrap!is!thus,!per!force,!a!species!that!depends!on!viable!
metapopulation!dynamics.!!If!populations!are!not!regularly!establishing!at!a!rate!sufficient!
to!balance!those!being!continuously!lost,!the!species!will!not!persist!in!that!habitat.!!Both!
water!and!fire!play!key!roles!in!maintaining!the!conditions!that!support!this!balance.!!
Although!it!is!usually!difficult!to!estimate!rates!of!population!establishment!and!loss!and!to!
track!which!source!populations!donate!seeds!to!colonize!new!habitats,!the!genetic!tools!we!
turn!to!next!provide!some!hope!that!we!may!eventually!be!able!to!estimate!these!as!well.!!
!
3.8. Population&genetics&
Given!that!small!and!dispersed!populations!now!represent!most!of!the!total!population!of!
the!Venus!Flytrap!with!few!large!populations!persisting!in!the!wild,!it!behooves!us!to!learn!
all!we!can!about!what!population!genetic!variation!exists!in!this!species!and!how!it!is!
distributed!within!and!among!populations.!!Given!that!this!species!appears!to!rely!on!seed!
dispersal!to!colonize!new!sites,!it!may!be!subject!to!regular!population!bottlenecks!that!
could!restrict!levels!of!population!genetic!variation.!!Likewise,!the!loss!of!many!populations!
Venus!Flytrap!p.!!
18!
noted!above!and!in!Fig.!4!may!reflect!depletion!of!adaptive!genetic!variation!and!possibly!
locally!adapted!ecotypes.!!Population!genetic!variation!can!be!very!low!in!other!rare!
species!subject!to!similar!meta-population!dynamics!tied!to!disturbance,!e.g.,!Furbish's!
Lousewort!(Waller!et!al.!1988).!!!
!
As!the!Venus!Flytrap!is!a!species!that!is!declining!in!the!number!of!occupied!sites!and!in!
population!size!within!many!sites,!we!should!seek!to!learn!all!we!can!about!the!amount!and!
structure!of!the!genetic!variation!its!remaining!populations!maintain.!!Population!genetic!
surveys!are!needed!to!assess!overall!levels!of!genetic!variability!(affecting!long-term!
adaptability!and!survival),!any!geographic!variation!that!may!be!present!(suggesting!local!
ecotypes!and/or!the!presence!of!unique!genetic!variants),!and!levels!of!inbreeding!within!
individual!populations.!!The!amount!and!distribution!of!genetic!variation!affects!a!species'!
ability!to!adapt!to!local!changes!in!environmental!conditions.!!In!addition,!small!
populations!are!subject!to!genetic!drift,!the!accumulation!of!deleterious!mutations,!fixation!
of!the!genetic!load,!and!inbreeding!depression!reflecting!the!expression!of!deleterious!
mutations!in!homozygous!combination!(Keller!and!Waller!2002).!
!
The!North!Carolina!Botanical!Garden!and!Carolina!Center!for!Genome!Sciences!recently!
initiated!a!new!project!to!sample!Dionaea!populations!across!its!range!for!both!tissue!and!
seed!germplasm!(Randall!!&!Kunz!2016).!!This!broad!survey!will!also!apply!a!genomic!
approach!("Next!Gen"!RAD-seq)!to!evaluate!DNA!sequence!variation!within!and!among!50!
Flytrap!populations.!!The!goals!of!this!work!include!testing!for!isolation!by!distance,!
detecting!sub-specific!variation,!and!searching!for!evidence!of!reduced!genetic!variation!
and!population!bottlenecks,!particularly!in!peripheral!populations.!!!
!
4. Geographic&range&and&population&status&
4.1. The&shrinking&range&of&the&Venus&Flytrap&
The!Venus!Flytrap!has!been!found!to!occur!naturally!only!in!the!Coastal!Plain!of!
southeastern!North!Carolina!and!far!northeastern!South!Carolina!(Fig.!4;!Coker!1928;!NC!
Natural!Heritage!Program!Database!2014).!!Here,!it!is!specifically!native!only!to!suitable!
habitats!within!a!130!km!radius!of!Wilmington,!North!Carolina.!!These!habitats!used!to!
cover!thousands!of!square!miles!of!the!lower!coastal!plain!of!North!Carolina!(Kerr!1875).!!
Most!of!the!vegetation!most!critical!to!Dionaea!has!now!been!clear-cut,!drained,!and/or!
converted!to!agriculture!or!pine!plantations!(Kologiski!1977)!resulting!in!the!decline!and!
disappearance!of!many!populations!(Figs.!4!&!5).!
Herbarium!specimens!and!historical!records!indicate!Dionaea'muscipula'originally!
occurred!at!259&sites!in!21!counties!across!North!and!South!Carolina!(Radford!et!al.!1968;!
NC!Natural!Heritage!Program!Database!2014).!!More!recent!observations!suggest!that!the!
plant!survives!now!as!only!179&populations!in!12!counties!(11!in!NC!and!1!in!SC),!with!a!
notable!collapse!at!the!edges!of!the!species’!natural!range!(Figs.!4!&!5;!NC!Natural!Heritage!
Program!Database!2014;!SC!Heritage!Trust!Database!2016).!!Much!of!this!collapse!has!
occurred!in!inland!populations!close!to!development!and!population!pressures.!!The!loss!of!
so!many!populations!has!had!the!consequence!of!increasing!the!isolation!among!remaining!
Venus!Flytrap!p.!!
19!
populations.!!Reductions!in!many!local!populations!is!likely!to!have!concomitantly!reduced!
the!reproductive!potential!of!these!populations!as!remaining!stands!have!become!
increasingly!isolated!from!one!another,!limiting!opportunities!for!pollination!and!
increasing!the!likelihood!for!inbreeding!and!the!loss!of!genetic!variation!(see!sections!3.8!
and!6.5).!!For!example,!the!Sandhills!populations,!located!on!the!Fort!Bragg!U.S.!Army!
military!installation,!are!now!separated!by!more!than!80!km!from!all!other!Dionaea'
muscipula'sites!(Fig.!4).!!
!
!
Figure&4.&Current!and!historical!range!based!on!North!Carolina!Natural!Heritage!
Program!database!from!2014!(credit:'Yari!Johnson).!!Data!for!South!Carolina!were!
unavailable!despite!several!requests.!!
!
4.2. Population&surveys&and&locations&
Populations!of!the!Venus!Flytrap!originally!ranged!from!Pamlico!County,!North!Carolina,!
south!to!Charleston!County,!South!Carolina!(an!historic!population!only;!Pittman!pers.!
comm.).!!Among!the!remaining!populations,!40%!are!very!small!containing!only!10-100!
individuals!(North!Carolina!Natural!Heritage!Program,!Fig.!5).!!Two!exotic!populations!also!
exist,!one!in!New!Jersey!and!another!in!Florida!(NatureServe!2015).!!These!populations,!
however,!are!small!and!solitary.!!They!are!also!useful,!however,!in!that!tracking!any!
expansion!in!these!populations!may!allow!us!to!infer!dispersal!distances!and!perhaps!other!
useful!population!parameters.!!Dr.!Tom!Smith!at!Florida!State!University!is!tracking!the!
Florida!population!for!just!these!reasons.!Nevertheless,!NatureServe!(2015)&concludes,!
Venus!Flytrap!p.!!
20!
“These!extra-limital!transplants!are!considered!inconsequential!to!the!conservation!of!the!
species.”!!
Although!most!plants!remaining!in!the!wild!are!found!on!“protected”!lands,!only!16%&of&
the&total&populations&are&considered&to&have&minimum&viable&populations!(North!
Carolina!Plant!Conservation!Program,!unpublished!data).!!This!leaves!the!majority!of!
populations!at!risk!of!extinction!for!stochastic!reasons.!!Of!the!four!main!clusters!of!flytrap!
populations!(Croatan!National!Forest,!Marine!Corps!Base!Camp!Lejeune,!Holly!Shelter!
Game!Land,!and!the!Boiling!Spring!Lakes!Preserve),!only!the!Boiling!Spring!Lakes!Preserve!
is!managed!for!this!plant!species.!!Many!of!these!populations!occur!in!low-lying!areas,!
making!them!vulnerable!to!storm!surges!and!rises!in!sea!level!(see!Section!6.5).!
!
!
Figure&5.!!Current!map!showing!the!status!of!populations!of!Dionaea'muscipula.!!The!
map!shows!extant,!historical,!and!known!extirpated!populations!across!the!
geographic!range!of!Dionaea.!!Note!the!loss!of!many!populations!(including!its!
largest),!the!many!small!populations!(ranks!C,!D,!and!E)!and!the!scarcity!and!
circumscribed!range!of!healthy!populations!(ranks!A!and!B).!!Source:!!Randall!&!
Kunz!2016.!!!
!
4.3. Record&of&population&declines&
Venus!Flytrap!p.!!
21!
Since!the!first!range-wide!inventory!in!1958,!half!the!known!Venus!Flytrap!populations&
have&disappeared!(Randall!&!Kunz!2016),!including&all&those&from&14+&counties.!!Venus!
Flytrap!populations!continue!to!disappear!at!a!non-sustainable!rate,!with!a!23%!decline!in!
sub-populations!occurring!during!a!single!recent!ten-year!interval!that!post-dates!the!US!
Fish!and!Wildlife!Service's!1993!decision!not!to!list!this!species!(1992!–!2002,!Randall!&!
Kunz!2016).!!Populations!continue!to!decline!and!disappear.!!In!2005,!more!than!100!
flytrap!population!sites!were!identified!in!Southeastern!North!Carolina.!!By!2013,!another!
1/3!of!extant!populations!had!been!lost,!slipping!to!just!67!(North!Carolina!Natural!
Heritage!Program).!!Of!these!67!populations,!only!42!populations!exceed!a!minimally!viable!
population!census!size!of!N!=!500!individuals!(Fig.!5;!see!also!Fig.!88!in!Evans!et!al.!2012).!!
Of!these!42,!only!nine!(9)!populations!are!judged!to!have!"excellent!viability"!according!to!
botanists!with!North!Carolina's!Natural!Heritage!Program.!!None!of!these!populations!are!
designated!specifically!for!flytrap!protection.!!Collectively!these!support!less!than!2%!of!its!
original!population!size!(Evans!et!al.!2012).!!
!
It!is!also!of!great!concern!that!populations!continue!to!disappear!even!from!public!lands!
and!in!areas!where!botanists!have!carefully!delineated!populations!and!warned!others!
about!exactly!where!these!populations!are.!!In!fact,!there!was!even!destruction!of!plants!
and!whole!populations!on!federal!lands!due!to!construction!activities!in!2016.!!!
!
Figure&6.!!Declines!in!the!total!wild!Venus!Flytrap!(Dionaea'muscipula)!population!
from!1979!to!2012!based!on!estimated!sales!(1979)!and!population!counts!(1982,!
1992,!2002,!2012)!from!the!North!Carolina!Plant!Conservation!Program.!!a)!!Linear!
scale,!points!connected!by!lines;!!b)!!Log!scale,!line!showing!smoothing!spline!fit!
(lamba!=!100,!r2!=!0.9).!!Declines!over!the!past!20!years!have!averaged!1.8%!per!
year.!!Data!used!with!permission!from!Evans!et!al.!(2012).!
As!the!number!and!extent!of!the!remaining!populations!have!declined!(Fig.!5),!so!has!the!
estimated!total!population!size!of!the!Venus!Flytrap!(Fig.!6).!By!2015,!according!to!
Scientific!American,!fewer!than!35,000!flytraps!remained!in!the!wild.!!As!with!declines!in!
the!number!of!extant!populations,!these!declines!in!total!population!size!are!serious!and!
a)!
b)!
5
6
7
Log N
1980
1990
2000
2010
Year
Venus!Flytrap!p.!!
22!
sustained.!!Plotting!these!declines!on!both!linear!and!log!scales!reveals!both!the!overall!
dramatic!decline!in!total!population!size!(Fig.!6a)!and!the!fact!that!high!rates!of!total!
population!decline!continue!through!recent!censuses!(Fig.!6b).!!!The!rate!at!which!this!
species'!population!is!declining!appeared!to!diminish!in!the!late!1980s,!just!before!the!
decision!by!the!USFWS!not!to!list!this!plant!in!1993.!!However,!the!total!population!has!
continued!to!decline!at!an!average!rate!of!1.8%&per&year!(average!lambda!population!
multiplier!=!0.9818).!!This!rate!of!decline!corresponds!to!a!half-life!for!the!species!of!38&
years,!assuming!that!population!and!individual!losses!do!not!accelerate.!!Such!a!high!rate!of!
continuing!decline!in!population!numbers!clearly!signal!that!the!persistence!of!this!species!
is!now!threatened!throughout!its!range.!!!
!
5. Conservation&status&
5.1. Past&conservation&actions&
Previously!in!1993,!the!Venus!Flytrap!was!considered!for!protection!under!the!US!
Endangered!Species!Act.!!However,!the!US!Fish!and!Wildlife!Service!determined!that!it!was!
a!“Potential!candidate!without!sufficient!data!on!vulnerability,”!as!published!in!Federal!
Register!Volume!58,!Number!188,!Pages!51144!-!51190,!September!30,!1993.!!!Since!then,!
considerably!more!data!have!been!collected!including!the!detailed!data!on!population!
losses!and!population!trends!presented!in!Sections!3!and!4.!!These!results!strongly!support!
this!Petition.!!The!additional!demographic!and!genetic!surveys!now!underway!(see!Sections!
3.7!and!3.8)!will!fill!additional!gaps!and!would!complement!any!U.S.!Fish!&!Wildlife!Service!
activities!associated!with!listing!this!species,!delineating!critical!habitats,!and!other!steps!to!
protect!and!manage!its!remaining!habitats.!
The!U.S.!National!Wildlife!Federation!(2016)!classifies!the!species!as!"vulnerable."!!
Internationally,!Dionaea'muscipula!was!among!250!rare!and!threatened!plants!selected!for!
inclusion!in!the!first!IUCN!Plant!Red!Data!Book!published!in!1978!(Kew!2016).!!Dionaea'
muscipula!is!rated!as!Vulnerable!(VU)!(A1acd,!B1+2c)!according!to!IUCN!Red!List!criteria!
and!considered!Vulnerable!(G3)!under!NatureServe!criteria!(Schnell!et!al.!2000,!2006).!!It'
was!listed!on!Appendix&II&of&CITES!(Convention!on!International!Trade!in!Endangered!
Species!of!Wild!Fauna!and!Flora)!at!the!15th!meeting!of!the!Conference!of!the!Parties!
(Doha,!2010).!!This!group!regulates!international!trade!in!threatened!species.!!!
Today!Venus!Flytraps!only!survive!on!sites!that!are!owned!and!formally!protected!by!The!
Nature!Conservancy,!the!North!Carolina!government,!or!the!U.S.!military!(Fig.!7).!!
Nevertheless,!losses!continue!from!these!sites!(see!p.!19!and!below).!
Venus!Flytrap!p.!!
23!
&
Figure&7.&Current!and!historical!range!based!on!North!Carolina!Natural!Heritage!
Program!database!from!2014!with!non-Department!of!Defense!federally!managed!
lands.!Most!populations!do!not!occur!on!federal!lands!and!populations!on!federal!
lands!continue!to!disappear.!(credit:'Yari!Johnson)&
5.2. Current&regulatory&context&
Historically,!poaching!has!been!a!significant!threat!to!many!populations,!including!some!of!
those!that!were!thriving!the!best!and/or!occurring!on!public!lands!(e.g.,!the!Green!Swamp).!!
Many!poachers,!adept!at!avoiding!detection,!routinely!robbed!sites!of!1000!plants!or!more!
(Platt!2015).!!Even!when!poachers!were!caught,!penalties!until!recently!were!minor!(e.g.,!a!
$50!fine)!as!the!crime!was!only!a!misdemeanor.!!That!is,!collecting!Dionaea'muscipula'from!
publicly!or!privately!owned!land!without!permission!from!the!landowner!was!previously!a!
misdemeanor!in!both!North!and!South!Carolina.!Violators!in!South!Carolina!faced!a!
maximum!fine!of!$200!and!up!to!30!days!in!jail!(SC!ST!SEC!16-11-590),!while!violators!in!
North!Carolina!could!receive!a!maximum!penalty!of!sixty!days!in!jail!and!a!$1,000!fine.!!A!
civil!penalty!of!$2000!could!also!be!assessed!for!repeat!offenders!(NC!GS!§!106-202.19).!!!
!
In!2013,!a!thief!stole!>1000!plants!from!a!public!park!in!Wilmington,!NC.!!In!2014!another!
frequent!thief!was!sentenced!to!5.5!months!in!prison!for!stealing!almost!300!plants!from!a!
National!Park.!!Another!man!was!sentenced!to!80!days!and!a!$1,000!fine!(The!Guardian,!27!
July,!2016).!!Starting!December!1,!2014,!the!penalty!for!poaching!Venus!Flytraps!from!
public!or!private!lands!in!Brunswick,!New!Hanover,!Onslow,!and!Pender!counties!in!NC!was!
increased!to!become!a!Class!H!felony!(NC!GS!§!14-129.3).!!This!new!law!was!exercised!for!
the!first!(and!to!date!only)!time!in!2015!when!four!men!were!arrested!and!charged!with!
Venus!Flytrap!p.!!
24!
poaching!970!Flytraps!from!the!Holly!Shelter!Game!Land!preserve!in!North!Carolina!(Platt!
2015).!!This!was!roughly!3%!of!the!entire!wild!population!left!of!Dionaea.!!Two!of!these!
defendants!received!sentences!of!probation!while!23-year-old!Paul!Simmons!Jr.!was!found!
guilty!and!sentenced!to!6-17!months!in!prison!(with!the!fourth!awaiting!trial!–!The!
Guardian,!27!July,!2016).!!!
!
As!noted!above,'Dionaea'muscipula'is!listed!as!a!Species!of!Concern!-!Vulnerable!by!the!
North!Carolina!Plant!Conservation!Program!and!"Vulnerable"!by!the!IUCN.!!Horticultural!
nurseries!in!North!Carolina!are!thus!required!to!obtain!a!permit!before!collecting!
propagation!stock!or!offering!propagated!plants!for!sale.!!Permit!applicants!must!meet!the!
following!criteria!(Evans!et!al.!2012):!
!
1. Identify!the!source!of!the!initial!stock!of!plants!used!for!propagation;!
2. Demonstrate!that!all!protected!plants!to!be!offered!have!been!nursery!propagated!
and!grown!horticulturally;!
3. Allow!for!a!yearly!inspection!of!site!and!facilities!where!protected!plants!are!grown!
or!stored!for!offer;!
4. The!person!or!persons!offering!protected!plants!shall!maintain!records!of!all!
acquisitions!for!the!length!of!time!these!plants!are!in!his!possession.!Such!records!
shall!be!available!for!inspection!by!the!Department!and!recorded!on!the!permits!or!
certificates!of!origin.!
!
The!US!Fish!and!Wildlife!Service!lists!Venus!Flytrap!as!a!Federal&Species&of&Concern!
(FSC).!!This!is!an!informal&term!and!not!defined!in!the!federal!Endangered!Species!Act.!!In!
North!Carolina,!the!Asheville!and!Raleigh!Field!Offices!of!the!US!Fish!and!Wildlife!Service!
define!Federal!Species!of!Concern!as!those!species!that!appear!to!be!in!decline!or!
otherwise!in!need!of!conservation!and!are!under!consideration!for!listing!or!for!which!
there!is!insufficient!information!to!support!listing!at!this!time.!!Subsumed!under!the!term!
"FSC"!are!all!species!petitioned!by!outside!parties!and!other!selected!focal!species!
identified!in!Service!strategic!plans,!State!Wildlife!Action!Plans,!or!Natural!Heritage!
Program!Lists.!!On!the!state!level,!the!Venus!Flytrap!is!a!candidate!for!state-listing!through!
the!North!Carolina!Plant!Conservation!Program!(Randall!&!Kunz!2016).!
The'above'designations'have'conspicuously'failed'to'ensure'sufficient'protection'for'
the'Venus'Flytrap'to'sustain'healthy'and'unmolested'local'populations.'!The!persistence!
of!the!species!is!now!threatened.!!To!address!these!threats,!the!U.S.!Fish!&!Wildlife!Service!
should!move!immediately!to!list!Dionaea!as!federally!Endangered.!!Doing!so!would!
immediately!expand!protection!for!this!species!to!the!federal!level!under!the!1973!
Endangered!Species!Act,!allow!the!designation!and!protection!of!critical!habitat!for!this!
species,!increase!penalties!and!enforcement!against!poaching,!and!ensure!more!
comprehensive!and!coordinated!planning!to!protect!and!manage!these!populations!and!the!
habitats!that!support!them.!
Venus!Flytrap!p.!!
25!
5.3. Protecting&the&Venus&Flytrap&will&also&protect&other&rare&and&threatened&
species&and&habitat&types&
The!Venus!Flytrap!occurs!in!particular!habitats!(Sections!3.4!&!3.5)!that!also!support!many!
other!rare!and/or!threatened!species.!!This!means!that!protecting!the!habitats!that!support!
the!Venus!Flytrap!would!also!automatically!serve!to!protect!many!other!species!that!
depend!on!these!habitat!conditions!and!that!may!be!at!corresponding!risk!of!sustained!
population!declines!and!extinction.!!Quick!action!to!strongly!protect!the!Venus!Flytrap!and!
its!habitats!under!the!Endangered!Species!Act!(ESA)!could!therefore!serve!to!avoid!
endangering!other!species!and!having!to!separately!consider!listing!them!as!Threatened!or!
Endangered!under!the!ESA.!!!
No!better!icon!symbolizes!the!beauty!and!exceptional!floristic!diversity!associated!with!the!
Coastal!Plain!than!the!Venus!Flytrap,!“one!of!the!most!wonderful![plants]!in!the!world”!
(Darwin!1875).!!This!plant!evolved!unique!tactics!to!survive!in!wet,!nutrient!poor!soils!in!
areas!that!experience!frequent!fires.!!Venus!Flytrap!habitat!represents!a!unique!hotspot!for!
biodiversity!along!the!East!Coast!based!on!the!Rarity-Weighted!Richness!model!for!
Critically!Imperiled!and!Imperiled!(G1!or!G2)!Species!in!the!United!States!(NatureServe!
2015).!!Annually!burned!wet!pine!savannas,!which!Dionaea!favors!and!serves!as!a!
characteristic!component,!support!the!most!floristically!rich!plant!communities!at!small!
spatial!scales!documented!in!North!America!(Walker!&!Peet!1983;!Peet!et!al.!2014).!
The!habitats!occupied!by!Venus!Flytraps!support!a!broad!diversity!of!other!carnivorous!
plant!species,!native!orchids,!lilies,!and!other!rare!plants!and!several!rare!and/or!endemic!
animals,!including!the!Pine!Barrens!tree!frog!(Hyla'andersonii).!!This!diversity!was!recently!
formally!recognized!when!the!SE!coastal!plain!was!declared!the!newest!biodiversity!
hotspot!(#36)!supporting!>1800!endemic!plant!species!(Noss!2016).!This!further!
highlights!the!need!to!preserve!this!habitat!type!and!the!many!other!plant!and!animal!
species!that!depend!on!it,!many!of!which!are!in!decline!and!vulnerable!to!extinction.!!Thus,!
protecting!Venus!Flytrap!habitats!could!reduce!the!need!to!list!these!species!as!Threatened!
or!Endangered!in!the!future.!!!
5.4. Critical&habitat&needs&
The!petitioners!urge!the!Service!to!designate!critical!habitat!for!Dionaea'muscipula!
concurrently!with!listing!this!species!as!federally!Endangered.!!Critical!habitat!as!defined!
by!Section!3!of!the!ESA!is:!(i)!the!specific!areas!within!the!geographical!area!occupied!by!a!
species,!at!the!time!it!is!listed!in!accordance!with!the!provisions!of!section!1533!of!this!title,!
on!which!are!found!those!physical!or!biological!features!(I)!essential!to!the!conservation!of!
the!species!and!(II)!which!may!require!special!management!considerations!or!protection;!
and!(ii)!the!specific!areas!outside!the!geographical!area!occupied!by!the!species!at!the!time!
it!is!listed!in!accordance!with!the!provisions!of!section!1533!of!this!title,!upon!a!
determination!by!the!Secretary!that!such!areas!are!essential!for!the!conservation!of!the!
species.!16!U.S.C.!§!1532(5).!
Congress!recognized!that!the!protection!of!habitat!is!essential!to!the!recovery!and/or!
survival!of!listed!species,!stating!that:!classifying!a!species!as!endangered!or!threatened!is!
Venus!Flytrap!p.!!
26!
only!the!first!step!in!insuring!its!survival.!Of!equal!or!more!importance!is!the!determination!
of!the!habitat!necessary!for!that!species’!continued!existence…!If!the!protection!of!
endangered!and!threatened!species!depends!in!large!measure!on!the!preservation!of!the!
species’!habitat,!then!the!ultimate!effectiveness!of!the!Endangered!Species!Act!will!depend!
on!the!designation!of!critical!habitat.!H.!Rep.!No.!94-887!at!3!(1976).!
Critical!habitat!is!an!effective!and!important!component!of!the!ESA,!without!which!the!
Venus!Flytrap’s!chance!for!survival!diminishes.!!The!need!to!designate!critical!habitat!for!
this!rare!plant!is!magnified!by!great!declines!in!its!range!and!number!of!populations!(Figs.!
4!and!5),!its!perilously!low!population!size!(Fig.!6),!and!the!number!and!significance!of!the!
imminent!threats!it!now!faces!(Section!6).!Petitioners!thus!request!that!the!Service!propose!
critical!habitat!for!this!rare!plant!concurrently!with!its!proposed!listing.!!Some!Venus!
Flytrap!populations!already!exist!on!federally!managed!lands!including!the!Croatan!
National!Forest!and!military!bases.!!Several!Venus!Flytrap!populations!occur!on!non-
Department!of!Defense!federal!lands!(Fig.!7).!
!
5.5. Other&urgent&recovery&actions&needed&
Priority&Category&1:&&Tasks&needed&to&avoid&imminent&species&extinction&
1. Protection!of!all!remaining!extant!populations!as!an!Endangered!species!under!the!
ESA!including!full!federal!enforcement!of!statutes!that!preclude!harm!or!damage!to!
wild!plants!on!public!lands,!poaching,!and!all!activities!that!could!threaten!the!
extent!or!suitable!conditions!of!habitats!that!support!this!species.!!
2. Directives!to!all!federal!agencies!to!protect,!sustain,!and!actively!manage!Dionaea!
populations!residing!on!federal!lands.!!These!directives!should!include!provisions!to!
monitor!population!sizes!and!habitat!conditions!to!ensure!continuing!population!
viability!and!to!guide!adaptive!management!of!these!habitats.!
3. Support!to!state!and!local!levels!of!government!to!protect!and!monitor!plants!and!
populations!on!non-federal!lands,!promote!public!knowledge!about!these!plants,!
and!enforce!all!laws!that!serve!to!protect!these!plants!and!habitats.!!!
&
Priority&Category&2:&Tasks&needed&to&maintain&viable&populations!
1. Support!scientific!surveys!and!studies!of!remaining!wild!populations!in!order!to!
better!understand!its!life!history,!demography,!reproductive!biology,!population!
dynamics,!and!dependence!on!particular!habitat!conditions!and!disturbance!
regimes.!!!
2. Use!this!information!to!design!and!implement!active!management!activities!on!lands!
that!support!Venus!Flytrap!populations!and,!on!an!experimental!basis,!
reintroductions!or!plantings!onto!other!lands!not!currently!occupied!but!judged!to!
provide!suitable!habitat!conditions.!
3. Support!scientific!surveys!and!studies!of!the!amount!and!distribution!of!genetic!
variation!within!and!among!populations.!!Use!this!information!to!assess!the!nature!
Venus!Flytrap!p.!!
27!
and!extent!of!genetic!threats!to!individual!populations!and!possibly!the!species!as!a!
whole!and!the!corresponding!advisability!of!efforts!to!"genetically!rescue"!
populations!deemed!at!risk!of!inbreeding!or!inviability!and/or!exchange!genetic!
material!more!broadly!among!populations!to!ensure!gene!flow!and!adequate!levels!
of!genetic!variability.!!!
4. Support!a!public!education!campaign!to!alert!citizens!to!the!threats!to!this!species!
and!its!habitats.!!Cooperate!with!and!encourage!botanical!gardens!and!other!public!
and!private!entities!to!promote!conservation!of!this!species!by!means!of!education,!
research,!and!efforts!to!actively!conserve!more!habitats!(e.g.,!via!a!surcharge!on!
propagated!horticultural!plants!to!support!in'situ!conservation).!!!
!
6. Threats&and&criteria&for&listing&
6.1. &Losses&of&habitat&and&range&
As!noted!above,!the!Venus!Flytrap!is!a!geographically!restricted!endemic!species!with!a!
limited!range!(Fig.!4).!!Within!this!range,!the!Flytrap!has!suffered!extensive!levels!of!
habitat&destruction&and&modification!that!have!eliminated!many!populations!and!greatly!
curtailed&its&available&habitat&and&range!(Figs.!4!&!5).!!These!losses!threaten!its!
worldwide!distribution!and!persistence,!particularly!in!light!of!the!additional!threats!
enumerated!above.!!!
Its!endemism!makes!the!Venus!Flytrap!critically!dependent!on!sustaining!particular!wet&
pine&savanna&and&pocosin&habitat&conditions!within!its!limited&range!on!the!Carolina!
coastal!plains.!!Here,!low-nutrient!wet!soil!conditions!and!recurring!fires!serve!to!maintain!
the!open,!sun-lit,!damp!conditions!that!allow!Flytraps!to!thrive.!!Sandhill!Seep!communities!
are!found!on!wet!sands!underlain!by!clays!on!slopes!in!sand!ridges!or!sandhill!areas!
primarily!in!the!Sandhills!region,!but!are!also!present!in!scarps!and!sand!ridges!in!the!
Coastal!Plain!(Schafale!and!Weakley!1990).!!Declines!in!Flytrap!range!and!these!suitable!
habitat!conditions!have!contributed!directly!to!the!conspicuous!population!declines!
observed!in!this!species.!!These!dependencies!make!it!critical!to!sustain!hydrologic!
conditions!and!fire!regimes!similar!to!those!that!have!sustained!this!species!in!the!past.!!!
Many!wet,!open!habitats!required!by!the!Venus!Flytrap!have!been!encroached!upon!by!
shrubs!and!trees!growing!in!response!to!fire&suppression.!!Various!authors!(Frost!2000;!
Gray!et!al.!2003;!Luken!2005)!report!that!Dionaea!populations!thrive!under!frequent!fire!
regimes!and!there!are!indications!that!with!fire!return!intervals!greater!than!5!years,!Venus!
Flytrap!populations!crash!(NatureServe!2015).!!For!this!highly!fire-dependent!species,!even!
fire!return!intervals!greater!than!2!years!can!result!in!population!crashes!after!a!period!of!
approximately!5!years!(Frost!pers.!Comm.).!!On!Sandhills!Seeps,!Schafale!(2012)!notes:!
“These!ecotonal!communities!are!particularly!subject!to!shrub!invasion!with!
inadequate!fire,!and!are!largely!lost!amid!the!expanding!shrubs!of!adjacent!
Streamhead!Pocosins!in!most!places.!It!is!somewhat!unclear!how!extensive!
Venus!Flytrap!p.!!
28!
well-developed!ecotonal!seeps!would!be!with!a!more!natural!fire!frequency,!
but!they!would!be!much!more!abundant!than!they!have!become!at!present.”!
Community!structure!is!strongly!controlled!by!fire!regime,!and!with!fire!these!areas!are!
open!and!herb!dominated!and!somewhat!resemble!Pine!Savannas!but!can!quickly!shift!to!
shrub-dominated!understory!in!the!absence!of!fire!(Schafale!and!Weakley!1990).!Like!other!
small!natural!communities!in!sandhill!areas,!nutrients!mobilized!by!fire!may!be!available!to!
Sandhill!Seeps!even!if!they!do!not!themselves!burn!(Schafale!and!Weakley!1990).!Many!of!
these!Sandhill!Seep!areas!are!becoming!overgrown!with!shrubs!due!to!declining!fire!
frequency:!
“Although!collection!and!trade!as!a!novelty!item!have!contributed!to!the!
decline!of!Dionaea,!its!more!fundamental!problem!is!that!faced!by!the!great!
majority!of!Coastal!Plain!species!in!our!area!–!destruction!of!habitat!and!fire!
suppression.!In!the!fall-line!Sandhills,!Dionaea!is!now!restricted!to!a!very!few!
sites!on!Fort!Bragg;!in!the!central!Coastal!Plain,!it!is!also!nearly!extirpated.!
Substantial!populations!remain!only!in!the!Outer!Coastal!Plain,!primarily!in!
Brunswick,!Pender,!and!Onslow!counties.”!(Weakley!2015).!
Development!directly!drives!declines!in!Venus!Flytrap!populations!by!converting!suitable!
habitats!to!parking!lots,!golf!courses,!and!strip!malls!(Tucker!2010).!!Rates!of!development!
in!the!coastal!plain!of!the!Carolinas!are!high,!increasing!land!values!and!the!profits!to!be!
made!from!development.!!The!recent!loss!of!five!additional!Flytrap!populations!on!federal!
lands!occurring!after!reconnaissance!and!the!explicit!delineation!of!their!locations!(see!
Section!4.3)!provides!clear!prima!facie!evidence!that!existing!mechanisms!to!protect!
populations!of!this!species!are!inadequate!to!prevent!continuing!erosion!of!populations!to!
development.!
Increases!in!roads,!housing,!and!developed!lands!also!threaten!Venus!Flytrap!populations!
via!a!variety!of!indirect!mechanisms.!!Most!obviously,!development!acts!to!fragment!and!
isolate!remaining!patches!of!natural!habitat.!!Such!regions!then!lose!biological!integrity!and!
connectivity,!limiting!their!ability!to!sustain!Venus!Flytrap!populations.!!In!particular,!such!
regions!become!less!able!to!sustain!historically!dominant!fire!regimes!and!correspondingly!
suitable!conditions!for!the!seed!production!(via!successful!pollination),!dispersal!(along!
corridors!of!suitable!habitat),!and!colonization!events!that!sustain!metapopulation!
dynamics!in!this!species.!!As!populations!become!more!isolated!from!each!other,!ecological!
"rescue!effects"!occur!less!often!and!gene!flow!is!disrupted,!increasing!the!likelihood!of!
eroding!genetic!variation!and!inbreeding!within!these!populations.!
Another!indirect!effect!of!development!is!that!it!restricts!our!ability!to!sustain!suitable!
habitat!conditions!for!remaining!flytrap!populations.!!This!occurs!as!natural!hydrologic!
conditions!are!often!disrupted!as!more!impervious!surfaces!appear!in!the!form!of!roads,!
parking!lots,!and!buildings.!!Other!lands!may!be!drained!for!development.!!The!construction!
of!storm-water!ditches!and!infrastructure!further!alters!hydrology.!!Finally,!land!managers!
lose!their!freedom!to!conduct!prescribed!burns!frequently!and!at!suitable!times!as!they!
Venus!Flytrap!p.!!
29!
seek!to!avoid!generating!in!smoke!in!smoke-sensitive!semi-urban!areas.!!Habitats!
surrounded!by!more!development!are!difficult!to!manage!using!fire!(Evans!et!al.!2012).!!
Thus!even!formally!protected!habitats!become!at!risk!of!losing!flytrap!populations!as!
development!curtails!management!flexibility.!
6.2. Over-utilization&and&exploitation&
As!already!noted,!carnivorous!plants!are!of!great!interest!to!many!collectors!and!
aficionados.!!The!Venus!Flytrap!is!the!most!popular!of!all!and!is!sold!widely,!mainly!by!
commercial!propagators!and!sellers.!!Some!of!these!plants!are!propagated!in!captivity,!
usually!asexually!via!tissue!culture!or!more!conventional!vegetative!propagation.!!Such!
propagation!requires!adequate!facilities,!skill,!and!time.!!This!market!is!large,!but!most!of!
the!flytraps!sold!to!amateurs!last!only!a!few!weeks!or!months!before!dying!because!few!
have!the!resources,!patience,!and!skill!to!keep!these!finicky!plants!alive.!!This!sustains!a!
steady!demand!for!more!flytraps,!which!maintains!prices!and!thus!pressure!to!poach!plants!
from!wild!populations.!!More!formal!protection!and!regulation!of!what!plants!can!be!sold!
on!the!market!could!do!much!to!reduce!this!over-exploitation!of!the!dwindling!number!of!
wild!plants!and!populations.!!!!
From!the!early!1990s!to!the!present,!North!Carolina!allowed!a!relatively!constant!number!
of!commercial!Dionaea'muscipula!sellers!to!collect!plants.!!These!nine!documented!
nurseries!do!most!of!the!business!in!propagating!and!selling!Flytraps!(Evans!et!al.!2012).!
Frantz!(1991)!estimated!export!totals!of!approximately!1,000,000&Venus&Flytrap&plants!
per!year.!!At!that!time,!it!is!likely!that!many!or!most!of!these!plants!were!of!wild!origin.!!!
The!continuing!demand!for!this!species!encourages!poaching!and!even!theft!from!
nurseries.!!In!May!2013,!almost!90!percent!of!the!Venus!Flytraps!in!Wilmington’s!Alderman!
Park!were!stolen!(~1000!plants).!!Also!in!2013,!10,000!Venus!Flytraps!worth!$65,000!were!
taken!during!a!burglary!at!the!Fly!Trap!Farm!in!Supply,!NC.!!These!and!the!recent!theft!
associated!with!a!felony!conviction!represent!destruction!of!appreciable!fractions!of!the!
total!wild!population!of!this!species!(Section!5.2).!
Evans!et!al.!(2012)!note!the!strong!negative!impacts!that!poaching!has!caused.!!They!state!
that!it!“…is!still!widespread!and!rampant!and!it!is!unclear!if!this!problem!can!ever!be!
completely!removed.”!!Poachers!impose!particularly!strong!mortality!on!the!largest!plants!
(Luken!2005,!Evans!pers.!observ.).!!These!large!plants!have!many!more!flowers!and!fruits!
than!smaller!plants!and!thus!contribute!the!most!to!the!colonizations!and!metapopulation!
dynamics!that!sustain!this!species.!!When!such!size-selective!harvesting!is!maintained!over!
successive!generations,!we!expect!genetic!changes!to!occur!favoring!flowering!at!smaller!
sizes!instead!of!sustained!vegetative!growth.!!This!could!curtail!demographic!resilience!as!
smaller!plants!with!fewer!flowers!set!fewer!seeds.!!Such!selective!effects!have!been!
explored!in!populations!of!another!exploited!plant,!American!Ginseng!(Mooney!and!
McGraw!2007).!!
Because!the!Venus!Flytrap!can!be!readily!propagated,!the!commercial!propagation!
techniques!and!facilities!that!already!exist!for!this!species!could!be!readily!turned!to!the!job!
Venus!Flytrap!p.!!
30!
of!generating!plants!for!out-planting!to!augment!existing!populations!or!establish!new!ones!
in!patches!of!suitable!but!unoccupied!habitat.!!However,!without!a!formal!Recovery!Plan,!
there!is!little!incentive!or!leadership!to!pursue!this!important!work!of!actively!re-
introducing!plants!to!restore!existing!populations!and!establish!new!populations.!!!With!
formal!listing!and!such!programs,!however,!it!should!prove!possible!to!quickly!pursue!
active!restoration!and!population!supplementation!in!a!way!that!could!allow!Flytrap!
populations!to!quickly!rebound!and!recover.!!Thus,!given!what!is!known!already!about!this!
plant!and!its!habitat!requirements,!the!U.S.!Fish!&!Wildlife!Service!has!the!opportunity!to!
move!swiftly!here!to!obtain!a!conservation!success!with!this!species.!!
6.3. Disease&and&predation&
A!thorough!search!of!the!literature!reveals!no!information!on!the!incidence!of!diseases!on!
the!Venus!Flytrap,!their!consequences,!or!whether!they!represent!any!threat!to!population!
persistence.!!Similarly,!we!could!find!no!information!on!the!frequency,!severity,!or!
consequences!of!any!herbivory!on!this!species.!!This!is!to!say!simply!that!these!potential!
impacts!have!not!yet!been!examined!or!documented.!!The!absence!of!evidence!here!should!
not!be!taken!as!evidence!that!such!effects!do!not!exist!or!are!unimportant.!!Rather,!further!
studies!are!needed!to!confirm!their!possible!importance!and!how!these!threats!may!vary!
among!populations!and!areas!of!its!range.!
6.4. Inadequate&regulatory&protection&
Existing!regulations!and!efforts!to!protect!the!Venus!Flytrap!have!failed!to!halt!sustained!
declines!in!populations!of!this!species!in!recent!decades!(Figs.!2,!3,!and!6;!Evans!et!al.!
2012).!!The!population!declines!and!losses!documented!in!Sections!4.1!–!4.3!as!well!as!
recent!poaching!events!and!the!2016!loss!of!five!more!populations!on!federal!land!make!
clear!that!existing!regulations!and!enforcement!activities!fail!to!address!the!full!scope!of!
forces!threatening!the!persistence!of!this!species.!!We!have!documented!the!several!direct!
threats!Dionaea!faces!as!well!as!an!even!larger!set!of!indirect!threats.!!The!number,!
complexity,!and!compounding!and!interacting!nature!of!these!threats!demand!an!organized!
and!comprehensive!response!of!a!kind!that!only!the!federal!government!can!provide.!!!
!
We!also!wish!to!stress,!however,!that!the!states!of!North!and!South!Carolina!have!clearly!
demonstrated!their!commitment!to!protecting!the!Venus!Flytrap!and!its!habitats.!!Their!
many,!substantial,!and!increasingly!effective!efforts!at!protection!doubtless!played!an!
important!role!in!slowing!the!rate!of!population!decline!(Fig.!6b).!!Working!with!other!
organizations!like!the!North!Carolina!Botanical!Garden,!NatureServe,!and!state!Natural!
Heritage!Programs,!they!have!also!raised!public!awareness!about!the!plant!and!the!need!to!
conserve!its!habitats!and!stem!poaching.!!Increasing!legal!penalties!for!the!poaching!of!
flytraps!and!re-classifying!this!crime!from!a!misdemeanor!to!a!felony!in!North!Carolina!are!
likely!deterring!criminal!trafficking!in!this!species.!!More!highly!publicized!cases!could!
increase!the!effectiveness!of!this!deterrent.!!Nevertheless,!the!evidence!we!have!in!our!
hands!also!plainly!indicates!that!local!efforts!to!stem!poaching!and!protect!populations!
have!failed!to!address!all!the!causes!of!population!decline!or!stem!these!declines!enough!to!
prevent!extinction.!!The!number!and!scale!of!the!efforts!needed!to!protect,!manage,!and!
Venus!Flytrap!p.!!
31!
restore!wild!populations!of!the!Flytrap!simply!appear!to!exceed!the!immediate!capacities!of!
local!governments!to!adequately!provide!these.!!!
!
Thus,!existing&regulatory&mechanisms!are!inadequate!to!protect!this!species!and!the!
habitats!it!depends!on.!!Only!the!federal!government!has!the!comprehensive!mandate!and!
resources!to!swiftly!stem!the!decline!of!Venus!Flytrap!populations!and!thus!avert!
extinction!of!this!species.!!Insufficient!resources!and!mechanisms!exist!at!local!levels!to!
ensure!systematic,!inclusive,!and!sustained!efforts!to!protect!this!species.!!It!is!thus!
incumbent!on!the!federal!government!to!meet!these!challenges!and!its!obligations!under!
the!ESA!by!listing!the!Venus!Flytrap!as!federally!Endangered.!!!
!
(Note:!!Listing!under!the!ESA!would!activate!the!Lacey!Act!Amendment!for!plants.!This!
would!forbid!the!inter-state!trade!of!endangered!plant!species.!!While!this!might!appear!to!
threaten!the!substantial!horticultural!trade!in!legitimately!propagated!Venus!Flytraps,!
there!are!provisions!of!the!Act!that!would!allow!this!trade!to!continue!in!a!regulated!
fashion.!!!In!particular,!the!horticultural!industry!could!continue!to!sell!Flytraps!as!a!listed!
species!with!an!interstate!commerce!permit.!!Commerce!in!several!endangered!plant!
species!continues!under!this!provision.)!
!
6.5. &Other&threats&to&Dionaea&survival&
Climate&change&and&rising&sea&levels&represent!additional!immediate!threats!to!
remaining!populations!of!the!Venus!Flytrap.!!That!is,!these!factors!could,!alone!and!
particularly!in!combination,!further!threaten!to!reduce!or!destroy!populations!or!reduce!
the!suitability!of!the!Flytrap's!remaining!coastal!plain!savanna!habitats,!particularly!in!low-
lying!areas.!!Recent!climate!extremes!are!associated!with!recent!increases!in!plant!
mortality!and!losses!of!habitat.!!Thus,!it!is!susceptible!to!current!and!future!climate!change!
impacts.!For!example,!the!projected!0.5m!rise!in!sea-levels!in!the!21st!century!represents!a!
direct!threat!to!Carolina!Beach!State!Park!and!other!remaining!populations.!!As!sea-levels!
continue!to!rise!through!the!21st!century,!low-lying!coastal!plain!wet!savanna!habitats!for!
the!Venus!Flytrap!will!be!particularly!vulnerable!to!flooding!and!to!saline!intrusion!(Fig.!8).!!
!
We!have!recent!very!concrete!evidence!for!the!impacts!that!rising!sea!levels,!increasingly!
severe!storms,!and!the!risks!that!storm!surges!pose!for!the!Venus!Flytrap!in!the!form!of!
Hurricane!Matthew!(see:!!https://www.washingtonpost.com/news/capital-weather-
gang/wp/2016/10/11/horrific-rains-and-ocean-surge-hurricane-matthew-by-the-
numbers/).!!In!this!storm,!the!rain!that!fell!in!the!Southeast!was!equivalent!to!13.6!trillion!
gallons!of!water,!a!volume!equal!to!75!percent!of!Chesapeake!Bay!(Fig.!9).!The!Lumber!
River!in!North!Carolina!reached!a!record!24!feet!above!its!usual!level,!while!the!Tar!River!at!
Rocky!Mount!crested!seven!feet!above!flood!stage.!!Storm!surges!broke!records!along!the!
Carolina!coasts!with!seven!tide!gages!in!the!Southeast!setting!records!including!Hatteras!
and!Wilmington,!NC.!!The!highest!recorded!storm!surge!was!7.8!feet!above!the!ground!in!
Fort!Pulaski,!Ga.,!near!Savannah.!!!
!
Venus!Flytrap!p.!!
32!
!
Figure&8.!!Elevation!map!of!North!Carolina's!coastal!plain!where!many!Dionaea!
populations!may!be!threatened!by!storm!surges!and!rising!sea!levels.!
!
!
!
Figure&9.!!Rainfall!associated!with!Hurricane!Matthew,!October!2016.!!In!addition!to!
these!extraordinary!rainfall!levels,!coastal!areas!were!exposed!to!high!storm!surges!
that!broke!records!in!tidal!regions!along!this!entire!section!of!coast.!!Venus!Flytraps!
mostly!occur!<90!km!from!Wilmington,!NC.!!Source:!!
Venus!Flytrap!p.!!
33!
https://www.washingtonpost.com/news/capital-weather-
gang/wp/2016/10/11/horrific-rains-and-ocean-surge-hurricane-matthew-by-the-
numbers/!
!
It!is!too!soon!to!evaluate!the!impacts!these!recent!storms!have!had!on!Venus!Flytrap!
populations,!but!they!could!be!substantial!if!flooding!associated!with!these!record!rains!
washed!away!individuals!or!even!whole!populations.!!Saltwater!intrusion!accompanying!
the!storm!surge!may!also!have!salinized!some!flytrap!habitats,!making!them!unsuitable!for!
sustaining!flytrap!populations.!
!
Atmospheric!nitrogen&deposition!represents!another!potential!threat!to!the!persistence!of!
Venus!Flytrap!populations.!!Nationally,!an!estimated!78!federally!listed!species!are!affected!
by!nitrogen!pollution!(Hernández!et!al.!2016).!!Carnivorous!plants!are!strongly!adapted!to!
growing!in!open!conditions!on!soils!that!are!highly!nutrient!deficient,!e.g.,!the!sandy!soils!
that!support!Venus!Flytrap!populations!(see!section!3.4).!Because!they!are!short!and!light-
demanding,!Venus!Flytrap!plants!are!highly!vulnerable!to!being!overtopped!by!faster!
growing!and/or!denser!populations!of!more!competitive!plants!wherever!higher!even!
slightly!higher!nutrient!levels!support!such!growth.!!Plants!adapted!to!growing!at!low!
nutrient!conditions!are!thus!most!susceptible!to!nutrient!additions!as!can!occur!via!
atmospheric!nitrogen!deposition!(Stevens!2004;!Giordani!et!al.!2014).!!These!effects!are!
associated!with!declines!in!nutrient-sensitive!species!and!overall!plant!diversity!in!low!
nutrient!habitats!like!chalk!grasslands.!!Nitrogen!deposition!is!already!occurring!at!levels!
high!enough!to!reduce!plant!diversity!across!much!of!North!America!(Simkin!et!al.!2016).!!
Rare!species!appear!to!be!particularly!susceptible!to!nitrogen!deposition.!!Suding!et!al.!
(2005)!estimated!the!risk!of!species!loss!due!to!fertilization!as!>60%!for!the!rarest!species.!
Such!"terrestrial!eutrophication"!likely!poses!an!immediate!threat!to!Dionaea!populations!
in!any!areas!where!nitrogen!deposition!exceeds!even!8!kg/ha/year!from!local!(e.g.,!
agricultural)!and!regional!(e.g.,!industrial)!sources.!!No!one!has!yet!tested!for!these!effects,!
however.!!Threats!to!the!Venus!Flytrap!would!be!compounded!if!ground-!or!surface!waters!
are!also!becoming!richer!in!nutrients.!!If!such!threats!are!affecting!Flytrap!habitats,!it!will!
be!even!more!important!to!use!controlled!burns!in!these!habitats!to!limit!competitive!
growth!and!reduce!nitrogen!levels.!!!!
!
Finally,!the!Venus!Flytrap!may!also!be!threatened!by!genetic&factors.!!For!example,!if!
individual!populations!of!the!Venus!Flytrap!are!highly!adapted!to!very!local!conditions,!
changes!in!those!conditions!may!result!in!declining!levels!of!genetic!adaptation!that!could!
impair!individual!and!population!viability.!!More!generally,!the!ability!of!this!species!to!
adapt!to!changing!conditions!may!depend!on!the!levels!of!genetic!variability!it!can!sustain.!!
For!this!species!to!survive,!it!must!sustain!genetic!variation,!adapt!genetically,!and!be!able!
to!disperse!to!additional!suitable!habitats.!!Restricted!population!sizes,!particularly!in!
combination!with!limited!levels!of!gene!flow!via!pollen!and/or!seeds,!will!act!to!increase!
the!rates!at!which!genetic!variation!is!lost!via!drift!and!individuals!and!populations!
inbreed.!!Inbreeding,!in!turns,!acts!overwhelmingly!to!reduce!individual!and!population!
fitness!as!deleterious!mutations!are!exposed!in!homozygous!individuals!–!the!phenomenon!
known!as!inbreeding!depression.!!!
!
Venus!Flytrap!p.!!
34!
Because!we!have!no!knowledge!of!levels!of!genetic!variation,!inbreeding,!or!inbreeding!
depression,!we!cannot!provide!any!quantitative!estimate!of!these!risks.!!Nevertheless,!we!
do!know!that!small!population!sizes,!uncertain!reproduction,!inadequate!habitat!
management,!and!fragmentation!and!isolation!of!its!habitats!all!act,!individually!and!
particularly!in!combination,!to!increase!these!risks!by!constraining!local!levels!of!genetic!
diversity!and!adaptability!and!by!increasing!levels!of!fixation!within!populations,!
homozygosity,!and!inbreeding!depression.!!These!genetic!effects,!in!turn,!likely!impair!
individual!fitness,!population!demographic!resilience,!and!the!ability!of!local!populations!to!
colonize!new!habitats.!!Thus,!genetic!factors!pose!additional!potentially!significant!threats!
to!this!species.!!
!
7. Conclusion&and&summary&
Despite!being!widely!known,!popular,!and!widely!cultivated!in!captivity,!wild!populations!
of!the!Venus!Flytrap!are!geographically!highly!restricted!and!have!declined!steeply!in!
extent!and!numbers!in!response!to!illegal!poaching,!development!pressures,!and!the!loss!of!
habitats!experiencing!suitable!fire!regimes.!!Given!these!declines!and!immediate!threats,!
we!petition!the!U.S.!Fish!and!Wildlife!Service!to!list!this!species!as!Endangered!under!the!
Endangered!Species!Act.!!To!support!this!petition,!we!emphasize!that:!
&
Ø The!Venus!Flytrap!is!a!highly!localized!plant!with!a!specialized!and!taxonomically!
distinct!evolutionary!history.!!!
Ø The!Venus!Flytrap!has!lost!>95%!of!its!original!total!abundance!by!losing!many!of!its!
populations!and!having!many!others!decline!in!size!and!viability.!!This!has!shrunk!
its!range,!isolated!populations,!leaving!only!42!populations!>500!individuals!and!9!
fully!viable.!!Few!of!these!most!critical!populations!are!adequately!protected.!!
Ø Although!the!Venus!Flytrap!has!been!listed!as!"Vulnerable"!(IUCN),!a!"Species!of!
Concern",!etc.,!these!designations!do!not!provide!protection!under!the!Endangered!
Species!Act!and!have!failed!to!protect!this!species!from!continuing!declines!in!
population!number,!extent,!and!viability!since!the!USFWS!considered!this!species!
for!listing!in!1993.!!Existing!regulatory!mechanisms!have!failed!to!protect!this!
species!and!the!habitats!it!depends!on.!
Ø The!Flytrap's!unique!adaptation!–!aerial!snap!traps!–!have!made!it!a!widely!
celebrated!carnivorous!plant.!!This!has!added!to!the!threats!it!faces!by!making!it!
vulnerable!to!poaching!and!overexploitation.!Without!a!program!to!certify!seedlings!
as!coming!from!legitimate!sources!and!regulations!on!trading!this!species,!economic!
pressures!to!poach!wild!populations!continue.!Listing!the!Venus!Flytrap!as!federally!
Endangered!or!Threatened!would!enhance!efforts!to!restrict!this!illegal!poaching!
and!trade!in!illegally!collected!Venus!Flytraps.!!
Ø The!Venus!Flytrap!is!losing!habitats!and!habitat!conditions!critical!to!sustaining!its!
populations.!Rapid!economic!development,!shifts!in!hydric!and!fire!regimes,!and!
insufficient!active!management!of!its!habitats!all!threaten!to!reduce!or!eliminate!
remaining!populations.!Listing!the!Venus!Flytrap!as!federally!Endangered!would!
protect!remaining!extant!populations!from!development!and!ensure!suitable!active!
management!to!sustain!their!viability.&&Actively!managing!remaining!habitats!and!
Venus!Flytrap!p.!!
35!
working!to!protect!and!restore!additional!unoccupied!habitats!would!protect!both!
the!flytrap!and!other!rare!species!that!depend!on!these!habitat!conditions.!
Ø Climate!change!and!rising!sea!levels!further!threaten!Venus!Flytrap!populations!by!
modifying!or!removing!otherwise!suitable!coastal!plain!savanna!habitats!
particularly!in!low-lying!areas.!!Populations!may!also!be!vulnerable!to!genetic!
threats!that!have!not!yet!been!assessed.!
Ø Listing!the!Venus!Flytrap!as!Endangered!would!strengthen!efforts!by!scientific!and!
conservation!organizations!and!many!individuals!to!conserve!Venus!Flytrap!
populations.!
!
Because!of!the!perilous!status!of!the!plant’s!populations!and!the!drastic!decline!in!recent!
years,!we!ask!that!the!Service!protect!the!Venus!Flytrap!on!an!emergency&basis!while!
undertaking!its!status!review.!
!
!
8. Literature&cited&
Cameron,!K.M.,!K.J.!Wurdack,!R.W.!Jobson.!2002.!Molecular!evidence!for!the!common!origin!of!snap-
traps!among!carnivorous!plants.!American'Journal'of'Botany.!89!(9):!15031509.!!
doi:10.3732/ajb.89.9.1503!
Coker!WC.!1928.!The!distribution!of!Dionaea'muscipula.!Jour.!Elisha!Mitchell!Sci.!Soc.!43:221-229.!
Daniels!RB,!Buol!SW,!Kleiss!HJ,!Ditzler!CA.!1999.!Soil!systems!in!North!Carolina.!Technical!Bulletin!
314,!North!Carolina!State!University,!Soils!Science!Dept.,!Raleigh,!NC.!
Darwin!C.!1875.!Insectivorous!plants.!London:!John!Murray.!!Online!at:!!http://darwin-
online.org.uk/EditorialIntroductions/Freeman_InsectivorousPlants.html!
Evans!R,!Gibson!T,!Johnson!YB.!2012.!Conservation!Status!of!Venus!Flytraps.!!In!Tim!Bailey!and!
Stewart!McPherson,!editors.!Dionaea:!The!Venus’s!Flytrap.!Dorset!(England):!Redfern!
Natural!History!Productions.!p!127-141.!
Frost,!C.C.,!2000.!Studies!in!landscape!fire!ecology!and!presettlement!vegetation!of!the!southeastern!
United!States.!Ph.D.!dissertation.!University!of!North!Carolina,!Chapel!Hill,!NC.!
Gibson!TC,!Waller!DM.!2009.!Evolving!Darwin's!'most!wonderful'!plant:!ecological!steps!to!a!snap-
trap.!New!Phytologist!183(3):575587.!doi:10.1111/j.1469-8137.2009.02935.x!
Givnish!TJ.!1989.!Ecology!and!evolution!of!carnivorous!plants.!Pp.!243-290!in!Abrahamson!WG!(ed),!
Plant-animal'interactions.!!McGraw-Hill,!New!York,!NY.!
Givnish!TJ,!Burkhardt!EL,!Happel!RE,!Weintraub!JW.!!1984.!!Carnivory!in!the!bromeliad!Brocchinia'
reducta,!with!a!cost/benefit!model!for!the!general!restriction!of!carnivorous!plants!to!sunny,!
moist,!nutrient-poor!habitats.!!American!Naturalist!124:!479-497.!
Giordani,!P.,!V.!Calatayud,!S.!Stofer,!W.!Seidling,!O.!Granke,!and!R.!Fischer.!2014.!Detecting!the!
nitrogen!critical!loads!on!European!forests!by!means!of!epiphytic!lichens.!A!signal-to-noise!
evaluation.!Forest!Ecology!and!Management!311:29-40.!
Venus!Flytrap!p.!!
36!
Godfrey!RK,!Wooten!JW.!1981.!Aquatic!and!wetland!plants!of!southeastern!United!States:!
Dicotyledons.!Univ.!Georgia!Press,!Athens.!933!pp.!
Gray,!J.B.,!T.R.!Wentworth,!and!C.!Brownie,!2003.!"Extinction,!colonization,!and!persistence!of!rare!
vascular!flora!in!the!longleaf!pine!wiregrass!ecosystem.!Responses!to!fire!frequency!and!
population!size.",!Natural!Areas!Journal!23:210-219.!
Hernández,!D.!L.,!D.!M.!Vallano,!E.!S.!Zavaleta,!Z.!Tzankova,!and!J.!A.!E.!R.!Pasari.!2016.!Nitrogen!
pollution!is!linked!to!US!listed!species!declines.!BioScience!66:!213222.!
doi:!10.1093/biosci/biw003!
Keller,!L.!and!D.M.!Waller.!2002.!!Inbreeding!effects!in!wild!populations.!!Trends!in!Ecology!&!
Evolution!17:!230-241.!!!
Kerr,!W.C.!!1875.!!Physical!geography,!resume,!economical!geology,!Vol.!1.!!Geological!Survey!of!
North!Carolina.!!Raleigh.!!120!pp.!
Kew.!!2016.!!Kew!Science,!Kew!Gardens!(UK)!!http://www.kew.org/science-conservation/plants-
fungi/dionaea-muscipula-venus-flytrap!&
Kologiski,!R.L.!!1977.!!The!phytosociology!of!the!Green!Swamp,!North!Carolina.!!PhD!thesis,!
Department!of!Botany,!North!Carolina!State!University,!Raleigh,!NC.!!169!pp.!
Luken!JO.!2005.!Habitats!of!Dionaea'muscipula!(Venus'!Fly!Trap),!Droseraceae,!associated!with!
Carolina!Bays.!Southeastern!Naturalist!4(4):573-584.!
Mellichamp!TL.!2015.!Droseraceae.!Flora!North!America,!vol.!6.!!!Online!at:!!
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... The species is now cultivated in many countries for research, education, and horticultural trade, but its native range is restricted to a small area of North Carolina and South Carolina, where it is threatened by habitat loss, fire suppression, and poaching. The International Union for Conservation of Nature and the North Carolina Plant Conservation Program list the species as vulnerable, and it has been petitioned for listing under the US Endangered Species Act (Schnell et al. 2000;Robinson and Finnegan 2016;Waller et al. 2016). ...
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