httprovingRecoveryPlanningfor Species ThreatenedandEndangered Comparatiueanalysitof recoueryplanscan contributeto more effectiuerecoueryplanning Theodore C. Foin, SethP. D. Riley, Anitra L. Pawley,Debra R. Ayres,Tina M. Carlsen, PeterJ. Hodum, and PaulV. Switzer he E n d a n g e re d Sp e c i e s A c t ( E S A ) i s a rg u a b l y th e m o s t im por ta n t l e g i s l a ti o n p a s s e d by the United States Congress to protect speciesand their habitats (the us e of t he t erm " s p e c i e s " c o v e rs s p e c ies , s ubs pe c i e s ,a n d e v e n d i s ti n c t populat ions). T h e E SA h a s th re e m ajor pr ov i s i o n s (R o h l f 7 9 8 9 , S c hwalbe19 9 3 , Mu e l l e r 1 9 9 4 , N R C 1995, E as t e r-P i l c h e r1 9 9 6 l r.F i rs t, i t s t ipulat esa p ro c e s sfo r d e te rm i n i n g whet her or n o t a c a n d i d a te s o e c i e s s hould be liste d a s th re a te n e do r e n danger ed, ba s e d s o l e l y o n s c i e n ti fi c information and specifically excluding pot ent ial e c o n o m i c i m p a c t. S e c ond, it pr ov i d e s l i s te d s p e c i e sw i th legal protection to reduce the threat of ex t inc t ion . T h e p ri n c i p a l p ro te c (' 1 4 [s " -1 [x t i s , to t ions ar e lim i ts to t he des t r uc t i o n o f a l i s te d s o e c i e so r Theodore C. Foin (e-mail:tcfoin@ucdavis. edu) is a professor,SethP. D. Riley (e-mail:
[email protected])is a graduate student, and Anitra L. Pawley (e-mail: alpawley@ ucdavis.edu)is a postgraduateresearcher in the Division of Environmental Studies, Universityof California, Davis, CA 95616. Debra R. Ayres (e-mail:drayres@ucdavis. edu) is a postdoctoral fellow at the Bodega Marin e L ab or at or y , Bodega Bay , CA 94923.TinaM. Carlsen(e-mail:carlsenl@ llnl.gov) is an environmental scientistat the Lawrence Livermore Laboratory, Livermore, CA 94551. PeterJ. Hodum (e-mail:
[email protected])is a graduate student in the Department of Animal Science, Universityof California, Davis, CA 95616. Paul V. Switzer (e-mail:
[email protected])is an assistantprofessor in the Department of Zoo log y, Ea s t er n I llinois Univ er s it y , Charleston,lL 61920. A 1998 American In stitu teof Bio logic alSc ienc es .
March 1998
l ati on recovery. Thi s inf or m at ion is used to construct t he downlist ing Identifying patterns cri teri a, usual l y a sp ecif iedpopulati on si ze, but i t ma y include addiacrossspeciesand ti onal provi si ons.suc h as a m inim um number of viablepopulation segments environments may or a set of habitat conditions. After lead to more effective review and revision, the lead agency approvesand filesthe recoveryplan; it recovery plans subsequentlyservesas a guide to rehabilitating the speciesin question,until and endangered i t i s repl aced by a re visedplan. The val ue of recover y planning speciesmanagement has been undercut sever elyby lim ited data and uncertainty in the plans. i ts habi tat-as w el l as the potenti al V ery few speci essee mt o have r ecovto hal t devel opment proi ects that ered to the point of downlisting bemi ght i ncreasea l i sted speci es'ri sk cause of the E S A . Ref f alt ( 1988) o f exti ncri on. Thi rd, i t requi res a cl ai med that onl y five specieshad recovery plan, a detailedprogram for been recovered beca useof t he ESA; reducingthe threat of extinction of the more soeci eshave b een downlist ed listed speciesby meetingspecifiedcri- through apparent ext inct ion t han through any form of r ecover y. teria (i.e.,the downlisting criteria). ' W i l c ove ( 1994) est iRecovery planning is potentially McMi l l an and th e most i mportant part of the E S A . mated that seven so ecieswent exU n l i ke the other provi si ons, i t i s spe- tinct after listing and another 17 that cifically intended to promote an in- w ere candi date soec ieswent ext inct c r ease i n the popul ati ons of l i sted before they were linally acceptedfor s p eci es,rather than to j ust l i mi t thei r l i sti ng. A N ati onal Resear chCouncil fu rther decl i ne.The E S A requi res an report (N R C 1995) f ound t hat six a pproved recoverypl an for al l l i sted speci esw ere dow nl ist ed becauseof s p eci es.The l ead agency (U S Fi sh the di scovery of addit ional populaand Wildlife Service [F\fS] or Na- ti ons or becauseof t he banning of ti o nal Mari ne Fi sheri es S ervi ce D D T, nei ther of w hi ch is evidenceof INMFS I) appoi nts a team of bi ol o- effective recovery planning. Other gists familiar with the speciesto con- authors have cri ti ci zedt he inadeauastruct the recovery plan, which con- ci es i n the structure of t he . ecouer y ta i ns an esti mate of the current si ze pl anni ng process (Cook and Dixon a nd state of the popul ati on(s) of the 1987, C ul bert and B lair 1989, Dixon l i sted speci es,an anal ysi sof the con- and C ook 1.989, Te ar et al. 1. 993, ditions that causedits endangerment, 1994, S chemskeet al. 1994) . Recova nd a sti pul ati on of the acti vi ti es ery pl anni ng to date d oesnot seemt o that will be required to support popu- have been very successf ul.
177
Tab le 1 . Dis t r ibut ion of t he 311 s pec iesw h o s e r e c o v e r y p l a n s w e a n a l y z e d .
Taxonomic group
Soecieslisted as if 3 June 1994
Amphibians Birds Clams crustaceans Fishes Insects Mammals Plants Reptiles Snails
9 73 40 4 63 I6 37 184 30 28
Total
484
Number of species covered by this analysis
Percentageof species covered by this analysis
7
13 29 82 24 28
78 85 75 00 51 B1 78 45 80 00
311
64
Under s ta n d i n g w h y th e p ro s p e c ts f or r ec ov e ry p l a n n i n g s e e m b l e a k i s eas y( T ea r e t a I. 1 .9 9 3 ,1 ,9 9 4 ).R e c o v er y t eams u s u a l l y w o rk u n d e r th e c ons t r ain ts o f l i ttl e m o n e y , c o n fl i c ting int er e s tg ro u p s , a n d l i ttl e ti m e i n whic h t o p ro d u c e a re c o v e ry p l a n . T hev m u s t a tte m D t to re h a b i l i ta te s pec ieson th e b ri n k o f e x ti n c ti o n b y the time they are listed. These problem s ar e e x a c e rb a te db y th e l i mi te d inf or m at i o n a v a i l a b l efo r mo s t l i s te d species (Schemskeet al. 1994). De' spite these difficulties, the effectivenes sof t h e E SA s h o u l d u l ti m a te l y b e m eas ur e d b y h o w m a n y s p e c i e sre c ov er t o th e p o i n t o f d e l i s ti n g b e l covc aus e of th e E SA . Su c c e s s fu re er y plan n i n g to p re s e rv e e x ta n t s pec iest,o p ro te c t th e w i l d a re a sth a t , n d to p ro v i d e s uppor t t h e s es p e c i e s a for the evolution of future diversity r epr es en tsa m a j o r c h a l l e n g efo r c o n s er v at ionb i o l o g i s tsa n d e c o l o g i s tsi n the coming decades.Even if improved r ec ov er y p l a n n i n g d o e s n o t d ra m a ti cally increasedownlisting in the short t er m , it g i v e s re s e a rc h e rsa n o p p o rtunity to gain data and insight into t he dy nami c s o f e n d a n g e re ds p e c i e s . Knowing how to achieve better r ec ov er y p l a n n i n g i s n o t s o e a s y . B ec aus e i t i s l i k e l y th a t a d e q u a te dat a will n e v e r b e a v a i l a b l e , n e w appr oach e s a re c o n s tra i n e d to u s e what data exist effectively. Patterns em er gingfro m c o m p a ra ti v e a n a l y s i s ot r ec ov e ry p l a n s s e e mm o s t p ro ml s ing. Flather et al. (1994) analyzed regional and environmental differenc es in th e d i s tri b u ti o n o f l i s te d speciesto identify the factors associat ed wit h th e i r l i s ti n g a n d u s e d th i s information to suggestthat regional differentiation in recovery planning is neede dto d e v e l o p a n d i mp l e m e n t r ec ov er y p l a n s m o re s u c c e s s fu l l y . 178
OL
30 4 .)z
One of thei r pri nci pal concl usi ons concerns the i mportance of al tered 'Western states surface water irrthe as a cause of threatenedexti ncti on. S i mi l arl y, D obson et al . (1997) have show n that comparati ve anal ysi s of recovery pl ans may reveal l argerscale patterns that may strengthen existing recovery plans and make new ones easi erto devel op. In this article, we analyze more than 300 recoverypl ans,concentrating on the causesof extinction and their taxonomic, habitat, and ecological correl ates.Our obi ecti vesw ere to detect broad-scalepatterns that can increasethe value of recovery planning and to evaluate the need for managementi nterventi on i n speci es recovery.
Analysis of recovery plans W e anal yzed 64% of the recovery pl ans approved or avai l abl e i n draft form throughmid-1994. We included al l of the recovery pl ans for snai l s and crustaceansand at l east 7 57" of the plans for all other groups except pl ants and fi shes (Tabl e 1). E ach member of our group analyzed all the fi l es i n a gi ven taxonomi c groupi assignmentsof responsibility to taxonomi c groups w ere made accordi ng to expertise. For each recovery pl an, w e concentrated on finding information in the pl an beari ng on al l causes,past and present, that l ed to the speci es becomi ngthreatenedor endangered. B ecausetermi nol ogy vari es among authors of recoverypl ans, w e devel oped a l i st of causesfrom a prel i mi nary subset of recovery pl ans that w oul d permi t us to compare di fferent ol ans. Tabl e 2 contai ns a l i st of the terms we used, with examples
draw n from the r ecover y plans. Usi ng thi s i nformation, we t hen ident ifi ed the pri nci pal causeof endanger ment; i n somecas es,it was necessar y '$7here to designatemore than one. information was poor, we conditioned our concl usi ons.All r em ainingcauses cited in the recovery plan were designated as contributing causes. \7e emphasize thatdecisionsabout pri nci pal and cont r ibut ing causesof endangerment repr esent our indivi dual j udgments and not t hose of pl an authors, al t hough som e plans did contain thesejudgments.'$7egeneral l y gave grea t er weight t o contemporary than t o hist or ical causes becausecontemp or ar ycausesshould be more important to current endangerment and mo r e r esponslve t o management.w e also t r ied t o det er mi ne and gi ve pr ecedencet o ult imate rather than pr oxim at e causes w hen appl i cabl e .For exam ple,if we determi ned that f ir e or logging opened vegetati o n gaps r esult ing in the i nvasi on of exot ic species,t hen we would designatelogging or fire as the pri nci pal cau se r at her t han t he exotic species.Generally, extracting causes of endan ger m ent f r om t he pl ans and deter m ining a pr incipal cause w as strai g ht f or war d and did not requi re exte nsive independent i nterprerati on. Assigning a par t icul ar si tuati on to o ne of our gener al causeswas occasionallydifficult. For example, when livestock grazing affectsan endangeredplant, is the princi pal cause of en danger m entdir ect popul ati on reduct ion,habit at r educti on, or habi tat m odif icat ion? O ur interpretation depended on the detai l s of the parti cular case.
Management categories Our ul ti mate object ive was t o place each lis.ted species in one. of three categorresof man agem entlnt enslt y, rangi ng from l owest m anagem ent i ntensi ty (habi ta t pr eser vat ion) ,t o greater effort (h abit at r est or at ion) , to hi ghest i ntensit y ( act ive m anagement). These cat egor ies wer e also devel oped from a pr elim inar y assessmentof recover y plans. I n br ief , habi tat preservat ionwas t he choice w hen i t w as dee m ed t hat a species coul d recover t o downlist ing if enough habitat were protected.Habitat restoratton was indicat ed if a BioScienceVol. 48 No. 3
Table 2. Definitions and examples of causesof speciesendangerment used in this analysis. Cause
Definition
Examples
S u c c e s s i o na n d distu r b a n ce
Eco lo g ica l su cce s si oncreateshabi tat condi ti ons unfa vo r a b le fo r th e listed speci es.We use di sturbancei n a r e str icte d se n seto mean a natural di sturbancethat m a in ta in s in te r m edi ate seral stages.
Fi re-mai ntai nedpl ant communi ties i n the S an B runo chaparral . These pl ants ar e hos ts for the San Bruno elfin butterfly.
C o e r o l u r i o n a r y r e la tio n sh ip
A liste d sp e cie sh as an obl i gate coevol uti onary r e la tio n sh ip with another speci es;reducti on of one n e ce ssa r ilym e a n s reducti on of the other.
The val l ey el derberry l ong-horn b eetl erequi res the val l ey el derberry as habi tat i n ri pari an habi tats .
Exotic species
Successfulinvasion or deliberate introduction of the exotic is responsible for the endangerment of the liste d sp e cie s.
The predatory snatl Euglandina rosedhas el i mi nated Oahu tree snai l sw herev er the tw o speci esare sympatri c.
Hybridization
Cr o ss- b r e e d in gb etw een the l i sted speci es(usual l y a su b sp e cie so r co n gener)w i th a more cofi Imon rel ati ve threatens its identity.
A rare form of V i rgi ni a round-l e af bi rc h i s bei ng genetically swamped by its more common congener.
O t h e r b i o t i c i n t e r a ctio n s
Co m p e titio n , p r e dati on, or other i nteracti onsbetw een n a tive sp e cie sh a s reduced the popul ati on of the liste d sp e cie s.
Roseate terns are less competitive than the gulls w i th w hi ch they compete for ner r ri tes .
S p e c i a l i z e do r r elict h ch ir a r
T h e h a b ita t r e q u ired by the l i sted speci esi s ei ther h ig h ly sp e cia lize d(and usual l y natural l y rare and scatte r e d ) o r a r e lict of a formerl y more common habi tat ( th e r e d u ctio n o f habi tat bei ng due to natural causes).
The desert sl endersal amanderi s l i mi ted to seepagesthrough broken l i mestones l abs i n a srngl ecanyon i n C al i forni a.
Habitat reduction
Ha b ita t is r e d u ce d or destroyedbecauseof human activity.
D rai nage of many pool s i nhabi ted by des ertpupfi sh i s the root causeof endange rment.
H a b i t a t m o d i f i ca tio n
Ha b ita t su ita b ility i s reduced or destroyedas a resul t o f h u m a n a ctivity .
Disturbance of caves occupied by listed bats, such as the Ozark bi g-earedbat. A l though the cavesare i ntact, vi si tor use can h arm c ri ti c al life history stages.
P o p u l e r i o n r e d ucr io n ( h a r ve st)
The speciesis endangered by direct human harvest.
H unti ng, nest robbi ng, and acci dentalc atc h has harmed sea turtl es.
s pec iesc ould re c o v e r to d o w n l i s ti n g t hr ough a pr o g ra m o f h a b i ta t p re s e rv at ion s uppl e me n te db y h a b i ta t re s toration. All speciesnot meetingthese conditions were placed in the active m anagem en tg ro u p . (In th i s c o n te x t, m anagem en t re fe rs to h a b i ta t a n d ec ologic alpro c e s sma n a g e me n t,n o t s pec ies pop u l a ti o n ma n a g e me n t, s uc h as c apti v e b re e d i n g o r re l o c a t ion. ) T hes e c ri te ri a a re e x p l a i n e d i n more detail in the definitions for eac h m anag e m e n t g ro u p . Habitat preservation.In this category of m anagem e n t, a s u ffi c i e n t a re a o f habit at is s e t a s i d e fo r th e s p e c i e si n question,relying on natural processes to facilitate population recovery.This s t r at egyas s u me sth a t i t i s p o s s i b l eto protect sufficient habitat for the spec ies ,t hat t he s p e c i e sp re s e n tl y e x i s ts in at leas t p a rt o f th e h a b i ta t, a n d that the species is effectively prot ec t ed in t ha t h a b i ta t. A n y u n o c c u pied habit at w o u l d b e c o l o n i z e d b y nat ur al dis p e rs a l o r, i n s o m e c a s e s . by ac t iv e r elo c a ti o n .If th e s ea s s u m p Marcb 1998
tions are fulfilled for a given species, th en no other management shoul d b e requi red to recover the speci es, b e yond moni tori ng both the speci es a n d i ts habi tat to ensure that the a pproach i s w orki ng. Most of the speci esthat w e cl assi fied as likely to benefit from habitat preservation were threatened bY a singular and easily identified threat. F or exampl e, the R ocky Mountai n gray wolf (Canis lupus irremotus) has sufficient prey and habitat. This s u bspeci eshas recentl y beenrei ntrod uced i n parts of i ts hi stori c range. A s l ong as di rect ki l l i ng of w ol ves i s p revented,the subspeci esshoul d rec o ver w i thout di rect mani pul ati on of the habitat, prey species,or other e col ogi cal processes.S i mi l arl y, the l i sted speci esof the E ureka V al l ey dunesecosystemof Nevada and Californi a requi re l i ttl e more than protecti on from off-road vehi cl es; ade quate protecti on shoul d l ead to spontaneousrecovery of speciessuch as eveningprimrose (Oenothera auita eurel
