Reprinted from THESOLTHWESI-ERY 'r\i ~TLRAL~SI Vol. 50, No. 3, September 2005 Made in U17ltedStates wmer~ca
INLAND OCCURRENCE OF THE STRAND PLANT IYOMOEA Ir'fiIY-(2~41'K4K (CONVOLVULA(~EAE,)AROUND LAKE: NICARAGUA
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I~IOP~OC'C"Ifiijs-ic//~lci~ (I,.) Koth (rr~iI1-0rt~ftilie. there arc n low w;ilitall and 'I tlarrotv sattclt Cctnvolt ulac eae) is a pantropic '11 pet-ci~ni~~l~C'IC~ \tit11 o~c~t\i~)rinl1,irge rocks. beach plnrrt tvitll 4110~11: pink. flo\zret \ nnd tt'tter- \Ye sttrcliecl I. fii;r-rn/lrci~on the \houe of 1,aL.e disperseel scects. The plant pos~1essesa self-in- Sicaragun f ollo.ct,ing the metliod\ of Det all anct compatibifit) r-ncchnnism, ;zltl~ortghit is a pio- Thien 1 1989). IZP placect 1.5 1-111' quadrats 3 111 neer- specie4 (llai-tin, 1970; L)e\;ill i~udThie~l, apart along a transect that parallelecl the 1989). Ij)o,nora pry-r ri/).rcrr~ f orrtls patches just bench, beginning nenr the front of the poprl- abotc the high-tide lirre on coastal beaches and lation (closc to the water). The exact location cirlrles thr-ougllrtrit tropical ;ttlcX s~rbtiopicalnr- of the first q~rnclt-atitloilg the trallsect was ran- ens of the \sorlcl. The si~eof' a patch vitries dc- clomly chosen b) draxving a n~~mlm-.TFVO other pending 011 tvhether the 13each is accretirlg or transects tvere locatccl pktrallel to the first, with eroding, the reccncv anel intensitti of stol-1115, .5 rn bettveerr each transect. Ipomo~crfl~c-cclj19nt~ and lrri11rali activitt7.Ifjotno~c~ fjrs-ccii))ncj i\ orre of sterns root adventitiorisly, and the extent of an the most widel\ distributed beach plnnts (Rid- inclividtial plant cannot he easily cleterrnined, so we cotuntecl sterns loirger ttian 30 c111 in ley, 1930) and is often a component of the strnncl {Austin and M7eise, 1972; Porter, 19'73; length to cletei-lrsitre cien\itv. MTithineach quacl- Wliitten et al, 1984; Moret~o-Casasolaand Es- rat, we corultecl flouers, fruits, and seecllings. Iil'e also collected I. pp~-trrp.rnpseecls at Malaca- pejel, ISHCi; De%tll, 1992). The prirnary polli- to~ia,stored tllerrl in plastic bags, nnd checkecl nators of I. ppc-cclj~rc~ra1 e bee$, ,~lthoughbut- for bruclrid (~LI~ge~irru~)beetle larrae. terflies, moths, flies, beetle\, wasps, 'rnd ant\ Thick mats of I. Prs-ic~f~mr,occur almost corr- also visit the flowers (Devall ancl Thien, 1989). tinuously from Ckanada to Malacatoya. The Seecis of I. ~)P~-c(L~IT-~~Poften arc pnrasitifed by plants grow fi-otn the upper boundary of the the beetle hl~gccc~rzicZ(~z~cor/jzlzic (Bi-uchiclae) 13eacl1 to the high tick line. Other species in (Tel-an aild Iiingsolvei-, 19'77). this 'rreil itlclude water hyacinth (Eichho?nin Ijttomoija ~")Ps-~~I~)T(EPoccui-s 011 the coastal crnsszjjp5 (Martins) Solins), pennywort (Hjciro- beaches of 5 continents alid most tropical is- totyZc. Doncirirnsi.r Lam.), ancl water lettuce (Prsticx lands, as well as on tvarirl temperate \bores (St. rftnfzod~cL,.). Beyond the beach are grasses. In John, 19'70). 111 spite of its \vide cli\tribtition, Jrrne "L002, I. IPS-icrf,mrcolonies occurred on only rare occru1-rcnces of I. /!rr-cnjhct~in itllarld the t~eachat the village of Sapoii, in distrrrbed habitats II~LV~been cXocurnenteci (Guppy, 1906; areas, and at Cardenas and ColOn on the sorrth St. .Jot~n.1970; Arxstin, 1982; X~tstiir:inti Cay- shore of the lake, in patches at the high tide alcante, 1952). Here we report on ;In extensile line. The species isas present along the rocky poptllation oi I. jjrr-cc~fjt-ci~gt o~ri~ig011 the shores of some small islands in the lake near shore, of Lake Nicaragua in the interior of Nic- C;ran>tda, \vi th abunclan t water hvacinth srir- aragua, also listed in (1963) arrd Austin ronnding the shores, nrld on San Ferrrai~do (200 1 ) . and small islai1cls in the Solelrtinarne archipel- Lake Nicaragua is 8,000 kms in area, wit11 a ago. Ifjo,,om J~P~-/C~~)FCI~;iilso grew at the ferrv rlieall elevation of 2-5 ID, ;tnd 11a\ a totill dis- 1;ir~cliny:nt Snrl Jorge near Rins and in the \ol\ecl solid content of 0.07%'/(1,1r1ostly sodium town of hlo\ogalplr or1 the large i\lancl of Oirre- bicarhot~atc(xtx7101*, 1963). Sairrlt~beache\ are tepe. COIT~IXI~II011 the irestei-11 and tlorthei-11 \Ilol-e hlean stet11 clcn\itr):of the I. j)~s-cc~f)m~patch of the lake, ancl the sotttl~el-nshore is r-ockv. ;tt kIalacatova TI '15 16.6/111' (=tl>le 1) . h143ecrtr Jjre s'trrlplecl the heacl~along 1,ake Nicnrirgua floivcr derisit? was 3/m5 ar~clmean fruit clen- l-teai-the town of 12lalacato!a (Fig. I) in Sovenl- \it! \&as4.31'~'. So seedlings -were obsertecl in her 1997 and October 1998 nnd in the city of the qrraclrats. il1rgc1cc.t zr c /PU~OT~)?~~LSparasitifed C;ran,zcta in October 2000. The sandy beach 9.9% of I. ;fir$-cc1j)rrrrseeds (n = 344). There near hl\llalncitto\a is approxirnatel\ 15 111 \ride were fe~ersterns, floft~ers,and fruits irr qtuad- and slopes clo\vir toxvard the Isatel-. 111 C;rr-ulacta, rats along trmsec ts at C;rariada, but a fetu seed- FK,. I-Zl'tp of U~c,lr,tgrr,i \llowit~g1,'lL.e Nic,trilgr~,i,tllc
Ti131 1 I-,lftati (2 $1)) stern, i10tzc.t. I1 uit, nnti \cc,cIlirig cttt~sit\iilrtrnbc.~ pel rri" (of Ij~ciiriciijnyr r-ccqrcir on t llrc 1101 rlltr n shot t of I.,\ht Sic,tr agtl,r. I)nt,r uc.~c. c o1lcc tcct [Ioill 33 1-111<~tlitd~rlt\ J edc 11 Ioc iitio~l)'it 31'1- l,tc,lto\,t ill O( tobet of I!)C)R ,tlicI Iton1 (;rnir,ttl,r 111 0ctobc.r oi 2000. Flo\\tr d,tt,t f~ot~l.~~orrtitl tltc (;lrll of \ltxrco ,~ftc>ll)t\all (li?S7);stern, fr tiit. nl~tlscccilitlg cIetlirt\
- Ont stc~ilil~gItas snnlplect. September 2005 NOTES 383
lings tvere noted (Table 1).The stem densities 1990). Mann et al. (1990) considered it a Qua- of I, pes-caprae at hiIalacatoya and Granada were ternary structural depression that subsided as greater than that at 5 coastal locations around an asymmetric half graben along boundary the Gulf of Mexico (Devall and Thien, 1989), faults on its southwestern side. It seems that where the mean stem density ranged frorn 0.6 the lakes were never connected to the Pacific. to 5.8/m2 (Table 1). We suggest the density of For about 100 years after its founding in c I. pes-caprae stems was greater around Lake hTic- 1524, Granada Mias a thriving seaport for ships aragua because the plants were more protect- of up to 120 tons that traveled up the Sa11Juan ed from storms and hurricanes than are coast- River, which connects Lake Nicaragua with the al populations. Herbivory of I. pes-caprae in Caribbean. After that time, changes in the riv- populations around the Gulf of Mexico is erbed, as well as Dutch and English pirates, slight, and the species tolerates human distur- made the passage of large ships impossible, but bance (Devall, 1987). Fruit density was also small vessels continued to use the river to greater at Malacatoya (4.3/m2) compared to reach Granada (Carr, 1953). 0-3.5/m2 around the Gulf of Mexico. No seed- A shark (Carcharhinus leucas), as well as saw- lings were found at Malacatoya or at 4 of 5 locations around the Gulf of Mexico (Devall fish and tarpon (all marine species), occur in and Thien, 1989); in contrast, a few seedlings the freshwater of Lake Nicaragua and the San (0.2/m" were present at Granada. Megacerus Juan River. Thorson (1971) demonstrated that leucospilus were found in 0.5-1696 of seeds the sharks swim back and forth from the Ca- around the Gulf of Mexico, with more south- ribbean to the lake along the river. The river, erly populations exhibiting greater percentag- however, flows from the lake to the Caribbean es of parasitized seeds; the rate was 9.9% at (approximately 175 km), drops about 393 rn, Malacatoya. and contains several sections with named rap- The occurrence of this large inland popu- ids. Because I; pes-caprae seeds did not float up lation of I. pes-caprae is unusual. Ipomoea pes-ca- the river, we suggest that the seeds were inad- prae is a widely distributed colonizing strand vertently carried up the river on ships traveling species on tropical beaches throughout the to Granada, perhaps as early as the 1500s, or world (Sauer, 1959, 1967; St. John, 1970; Aus- were carried inland even earlier, given that the tin and Cavalcante, 1982; Fang and Staples, plant has been used medicinally for thousands 1995; Austin, 2001). It has reached nearly all of years. Water hyacinth, pennywort, and water the locations at which it occurs by drifting of lettuce are all non-natives and known "hitch- its seeds in the sea (Ridley, 1930). The species hikers", but all 3 are medicinal, so purposef~il also occurs on the back margins of beaches, introductions around Lake Nicaragua cannot along coastal roads (Wilson, 1977), and in be excluded. We have not observed birds eat- coastal villages, where it is dispersed by trans- ing I. pes-caprae seeds, which contain ergot al- portation of sand. It does not naturally invade kaloids (Jirawongse et al., 19'79), but this inland habitats (St. John, 19'70). Ridley (1930) would not preclude birds frorn eating them if stated that I. pes-caprae is never found inland, unless temporarily, after the seeds have been the birds did not break the seed coats. It is carried in sand. The landward extent of the possible that seeds were carried on the feet or species is limited by dispersal, competition, feathers of birds that were wet or muddy. Me- and shading by plants beyond the strand (De- gacerus leucospilus could have arrived in parasit- vall, 1992) . ized seeds along with viable seeds. The exten- It was formerly thought that Lake Nicaragua sive spread of the plant around the lake indi- and Lake Managua were formed when a large cates that it has been present for some time. bay was cut off frorn the Pacific Ocean by vol- canic activity (Hayes, 1899). Today it is thought We thank A. Rigarner and V. Rico-Gray for helpftil that the Nicaraguan depression, iticludi~~gthe reviews of the manuscript, and we thank J. Kingsol- 2 lakes, is a graben formed by subsidence dur- ver for insect identification. We appreciate infor- ing the late Tertiary and Quaternary (Thorson mation about birds from P. Hamel. We obtained the et al., 1966) or during the late Miocene map of Nicaragua from Enchanted Learning and (McBirney and Williams, 1965; Morris et al., added names of sites where I. pes-cupr~occurs. 384 7 hr Jo?~tlzzu~ctrm,Yatu~ni~st 101. 50, no. 3
patihilip in the Convolvulaceae. Botanical Ga- zette 131: 139-133. Acsrrs, D. F. 1982. Cont-olvnlaceae. 113: Z. Luces de kScB~trul.:\~,,4. R., AND H. WII.I.IAZ?S.1965. \;olcanic Febres and J. A. Steyermark, editors. Flora de Ve- history of Nicaragua. University