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Notice: ©1978 Rosenstiel School of Marine and Atmospheric Science, University of Miami. This manuscript is available at http://www.rsmas.miami.edu/bms and may be cited as: Gore, R. H., Scotto, L. E., & Becker, L. J. (1978). Community composition, stability, and trophic partitioning in decapod crustaceans inhabiting some subtropical sabellariid worm reefs: Studies on decapod crustacea from the Indian River region of Florida, IV. Bulletin of Marine Science, 28(2), 221‐248. BULLETIN OF MARINE SCIENCE, 28(2): 221-248, 1978

COMMUNITY COMPOSITION: STABILITY, AND TROPHIC PARTITIONING IN DECAPOD CRUSTACEANS INHABITING SOME SUBTROPICAL SABELLARIID WORM REEFS STUDIES ON DECAPOD CRUSTACEA FROM THE INDIAN RIVER REGION OF FLORIDA. IV

Robert H. Gore, Liberta E. Scotto, and Linda J. Becker

ABSTRACT A 2-year study consisting of quantitative and qualitative collections, both day (1974) and night (1975), was made on the decapod and stomatopod crustaceans inhabiting, or associating peripherally with, some sabellariid worm reefs on the central eastern Florida coast. The reefs investigated all occurred in the surf zone or just inside dredged and maintained inlets of the Indian River region, from St. Lucie Inlet northward to Sebastian Inlet. Quantitative and qualitative sampling indicated that at least 96 species of decapod and stomatopod crustaceans, in 52 genera and 22 families, may occur within, or in habi- tats adjacent to, the sabellariid biotope. The Quantitative Survey obtained 51 species, lO- II of which comprised nearly 90% of all collected individuals, and were sufficiently recur- rent to be labelled common. These 10-11, plus the next 13 species in abundance (= 24) contained 97% of all collected individuals and were considered characteristic of the decapod and stomatopod fauna on central eastern Florida sabellariid reefs. The remaining 27 species accounted for approximately 3% of all collected individuals and were designated as uncommon. The sabellariid-inhabiting macrocrustacean community is dominated numerically by three species, the porcellanid crab Pachycheles l1lonilifer, and the xanthid and grapsid crabs, Menippe nodifrons and Pachygrapsus transversus, respectively. To- gether, these three species made up 65% of all collected individuals obtained during quantitative sampling. Three other species, the pistol shrimp Synalpl1eus jritzmuelleri, and the xanthid crabs Pilumnlls dasypodus and Panopeus bermudensis, accounted for another 15% of all individuals coltected from these reefs. Species composition and rela- tive abundance and occurrence of the numerically important decapod crustaceans on these reefs was similar over both years of the study. Nutritional modes among the first three species suggested that trophic partitioning occurs. Gut content analyses and predator- prey relationships among the six most numerous species indicated that all feed to some extent on the sabellariid worms which construct the substratum of the biotope. The sabellariid bioherm thus offers hard substratum, protection, and food for these decapod species allowing them to utilize the surf zone habitat, an area where they would not normally be found. Persistence of the sabellariid biotope, and predictability of decapod species composition may account in some measure for the observed stability in the decapod community on these reefs. Two of the three most abundant species, Pachycheles l1lonilifer and Menippe nodifrons, are zoogeographically limited in their northern range to the Indian River region of Florida, and neither of these species occurs in large numbers outside of the sabellariid biotope. Their distribution along the central eastern Florida coastline appears to follow that of the sabellariid worm itself.

Members of the polychaete worm family dwelling tubes which, as development and Sabellariidae have long been noted for the increased settlement continues, eventually ability to form extensive "reefs" or bioherms coalesce to form large colonies within and in shallow marine waters. Species in the just seaward to the surf zone on shores family utilize sand particles and a muco- exposed to the open sea. Such colonies proteinaceous cement to construct their often support large associated faunas com- 221 222 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978 posed principally of crustaceans and molluscs (Rivosecchi, 1961; Achary, 1971; Fausto- Filho and Furtado, 1970; Gruet, 1970, 1971, 1972a, 1972b, 1973; Wilson, 1971). Nearly all of these studies have been carried out on Sabel/aria alveolata (Linne), a tem- perate-water European species. In the New World, Phragmatopoma lapidosa Kinberg, 1867, is a widely distrib- uted species which occurs primarily in trop- 28° ical marine waters from the vicinity of Santa Catarina, Brazil to the area of Cape Canaveral, Florida (Kirtley, 1966; Kirtley and Tanner, 1968; Fanta, 1968). Although the worms can be found along the eastern coastline of Florida from Biscayne Bay to Cape Canaveral, studies on the species in 30' this area have been devoted mainly to geological aspects of the worm reefs (Multer and Milliman, 1967; Gram, 1968) and the species has received only limited attention from biologists. Eckelbarger (1976) has described the larval development of Phrag- 27° matopoma lapidosa from the Indian River region on the central eastern Florida coast- line, but the only ecological investigations on the species have been brief studies in Figure 1. Map of the Indian River region on the Brazil (N archi and Rodrigues, 1965; Fanta, central eastern Florida coast, with dots showing the location of sabellariid worm reef stations 1968; Fausto-Filho and Furtado, 1970). sampled during 1974-1975. The Canova Beach Kirtley (1974) summarized both biological station was not continuously sampled (see text). and geological studies on P. lapidosa and related genera and species in the family Sabellariidae. more, in press). The decapod and stoma to- pod crustaceans on these reefs form a Large, exposed colonies of Phragmat- particularly noticeable faunal component opoma lapidosa occur throughout the length of the Indian River region of Florida, from estimated to account for approximately 90r" of the associated macroinvertebrate fauna, just north of Jupiter Inlet to slightly south and thus comprise an assemblage which of Melbourne, Florida about 50 km (30 would appear to lend itself to community miles) south of Cape Canaveral. Many of analyses. these colonies consist of discrete, semiiso- This paper reports on the results of a lated units within the larger framework of 2-year survey, begun in January 1974, that the sabellariid biotope. Preliminary investi- was directed toward determining species gations revealed that such colonies sup- composition, abundance, richness and diver- ported a large and varied invertebrate faunal sity of the decapod and stomatopod fauna assemblage consisting primarily of crusta- either inhabiting, or found in proximity to ceans, molluscs, sponges, bryozoans, and these reefs. Predator-prey and trophic re- anthozoans. These colonies also provide lationships in selected decapod species food and cover for small populations of both within the sabellariid biotope in the Indian transient and permanent fish faunas (Gil- River region were also investigated. In this GORE ET AL.: COMMUN1TY STABILlTY IN WORM REEF CRUSTACEANS 223

Figure 2. General view of three sabellariid worm reef stations sampled in the Indian River region: (A) St. Lucie Inlet; (B) Walton Rocks; (C) Ft. Pierce Inlet. The Sebastian Inlet station is similar to that at Ft. Pierce Inlet. All stations photographed at low tide, facing south. The St. Lucie and Wal- ton Rocks stations typify exposed-shore worm reefs; the Ft. Pierce Inlet station illustrates a more pro- tected area. Note the numerous holes and crevices in the worm colonies at each station. 224 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

paper we consider species composition and the trophic relationships of the numerically .•.. o important decapod species In the com- ;>. munity. II) E •..> o ::l ~ '" METHODS Samples were gathered in the Indian River region along the central eastern Florida coast between latitudes 27° and 28°N. Four areas were selected in 1974 for daytime sampling, three of which were also chosen for nighttime sampling in 1975. All con- u o" tained extensive, viable worm reefs. Pro- gressing from south to north these were (1) ,,; Seminole Shores, a beachside residential o Z subdivision just north of S1. Lucie Inlet, Martin County (hereafter called S1. Lucie oo Inlet); (2) Walton Rocks, an exposed series of coquinoid limestone ledges of the Anas- ci. tasia geological formation, located on an en" isolated beach on Hutchinson Island, S1. t:: (':j II) Lucie County, opposite a large nuclear- <.) .::l NNN NNN fueled power plant; (3) inside the mouth '"::l•.. of F1. Pierce Inlet, S1. Lucie County, be- <.) .•.. NNN tween the enclosing granite rip-rap jetties; o and (4) inside Sebastian Inlet, Indian River County, both alongshore and in the channel itself (Figs. 1 and 2). The latter station was eliminated for night sampling in 1975 NNNN because of the extremely swift and danger- ous current which prevails in the Sebastian :;:;-N Inlet channel. The total geographical range r-- 0'1....• of the survey area encompassed approxi- •.. mately 80 km (50 miles) from S1. Lucie to ::lVJ •...• 01) Sebastian Inlets. ::l i The 2-year investigation was divided into ~ two parts: (1) quantitative collections made •..<.) (':j directly on the reef (Quantitative Faunal ~ c '-' .S Survey), and (2) non-quantitative collec- •.... " "C~ tions made concurrently both on the reef .S'" and in habitats adjacent to it (Qualitative .5 Faunal Survey). Our original intent in both

Table 2. Numbers of families, genera, species, and individuals of decapod and stoma to pod crustacea collected from sabellariid worm reefs in the Indian River region of Florida, 1974-1975 ------SI. Lucie Walton Rocks FI. Pierce Sebastian 1974 1975 1974 1975 1974 1975 1974* Families 12 6 7 6 6 10 3 Genera 23 12 15 11 12 17 5 Species 37 14 20 13 22 25 8 Total Genera 25 18 18 5 Total Species 39 23 31 8

Total Number of Individuals per Species, Both Years Combined 1. Paehyeheles mOllilifer 127 163 256 None 2. Mellippe lIodifrolls 98 216 107 22 3. SYllalpllells fritzmllelleri 54 64 42 None 4. Paehygrapsils trallsverSIlS 51 48 56 66 5. Pilllmllils dasypodlls 17 15 64 None 6. Pitho lhermillieri 14 4 None None 7. Mithrax coryphe 14 2 6 None 8. GOllodactY/lls bredilli II 4 None None 9. Pilllmlllls sayi 9 None 18 None LO. Petrolisthes galathillils 8 1 14 None 11. Alphells formoslIs 8 None 8 None 12. Pagllrtls earolillellsis 8 1 1 None 13. Xa/ltllO delltieillatlls 7 3 None None 14. GOllodactY/lis oerstedii 7 None None None 15. Me/lippe mereellaria 6 20 24 3 16. SY/lalphells sp. A 6 None 4 None 17. Epialtlls bitilberclllatlls 6 None 10 None 18. A lplzells IIIl1tingi 5 4 9 None 19. Mierophrys bieorlllltlis 4 None 4 None 20. Plagllsia depressa 3 2 1 1 21. Pallopells bermlldellsis 2 15 44 4 22. Alphells thomasi 2 4 2 None 23. SYllalphells millllS 2 None 7 None 24. SYllalphells /owlIse/ldi 2 2 3 None 25. Uhlias limbatlls 2 None None None 26. Proeessa fimbriata 2 None 1 None 27. Metalplzells rostratipes 1 2 None None 28. Lysmata illtermedia I None I None 29. Petrolistlzes armatlls 1 1 1 None 30. Alphells /lorman IIi 1 None None None 31. Epialtlls dilatatlls 1 None None None 32. Alplze/ls paraerinitlls I None None None 33. Megalobraelzillm soriatllm 1 None None None 34. Mithrax aC/ltieomis 1 None None None 35. Neopolltollides beallfortellsis I None None None 36. Mit/mIx plellracallt/lIIs 1 None None None 37. Upogebia affillis 1 None None None 38. Platyactaea setigera 1 None None None 39. Mierop(lIlope gralllllimalllls 1 None None None 40. Mithrax lzispidlls None 2 None None 41. A /phells armillatlls None 1 4 None 42. Periclimelles americallllS None 1 1 None 43. Ellrypallopells dissimilis None 1 None None 44. Lysmata wllrdemalllli None None 1 None 45. SYlla/phells brevicarplls None None 1 None 46. A/phells bOllvieri None None 1 1 47. Pagllristes tortllgae None None 1 None

• Sebastian Inlet station not sampled in 1975, see text. 226 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

Table 2. (Continued)

SI. Lucie Walton Rocks Ft. Pierce Sebastian 1974 ]975 1974 1975 1974 1975 1974· Families 12 6 7 6 6 10 3 Genera 23 12 15 11 12 17 5 Species 37 ]4 20 13 22 25 8 Total Genera 25 18 18 5 Total Species 39 23 31 8 ---- 48. Eurypanopeus abbreviatus None None 1 None 49. A/pheus heteroehae/is None None 1 None 50. Panopeus oeciden tatis None None None 5 51. Panopeus herbstii None None None 1 ---- -_._---~.

last of one month into the first of the next, Quantitative Faunal Survey as in October-November, 1974. Foul Discrete worm reef colonies of varying weather also interrupted the continuous sizes were selected by sight at each station. monthly sampling regimen. The final sam- To ensure complete collections of all con- 2 pling regimen, mean area sampled (cm ), tained decapod and stomatopod individuals and mean numbers of species and individu- only easily dislodged, isolated colonies, als for each geographical area is listed in termed "heads" were taken. Those which Table 1. Total species listings and numbers had become widely coalesced with others of individuals collected at each quantitative (Fig. 3) or which had grown together form- station are presented in Table 2. The total ing large "tables" or platforms were judged decapod and stomatopod fauna collected too large to adequately sample. Nearly all appears in Appendix 1. macroinvertebrates, especially the decapod

Figure 3. A sabellariid "table" colony formed by the coalescence of several large "heads" at Walton Rocks. The broken and exposed portion of the table in the foreground illustrates the typical cross-sec- tion and complexity of large sabellariid colonies. Note the many crevices in the surface, and the ex- tensive cave-like holes in the base of the table, which can form refuges for decapod and stomatopod crustaceans. The coquinoid limestone base plate upon which these reefs are constructed is easily seen as a series of laminated rock ledges. The proximity of such reefs to the surf zone is also evident. GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 227

and stomatopod crustaceans, on the worm cies were also utilized in gut-content studies, reefs are cryptic or slow moving species. as discussed in more detail below. The methodology of collecting the entire worm reef head thus allowed a complete Studies on Newly Formed Sabellariid census of the individuals associated with the Colonies worm colony. Each head was dislodged at its base with a geological hammer. and placed In March 1975 we observed a settlement into large plastic buckets for transport back of Phragmatopoma lapidosa larvae at the to the laboratory. The sample, and all as- Walton Rocks station. At that time we sociated debris, was removed from the buck- initiated a second sampling program using et, and placed base downward in a large the same quantitative methodology noted stainless steel sorting pan. Each colony was above. In this instance, "average-sized" measured for length, width, and height to worm reef heads were estimated by sight the nearest 0.1 cm, according to the original and then selected from the newly settled orientation of the head in nature. The head colonies. This resulted in collections in was then carefully broken apart until com- which the individual colony sampled gradu- pletely pulverized. All contained decapod ally increased in size over a 6-month period. and stomatopod individuals (hereafter Because the postlarvae and juvenile sabel- termed macrocrustaceans) were removed lariid worms grew rapidly, we collected two from this debris and preserved in 70% worm reef heads semi-monthly, during the ethanol. Each individual crustacean was lowest daylight tide. Sampling was ter- identified to species, its sex determined, and minated after 6 months because the remain- carapace length and width in the crabs (cl ing "average" colonies of the new settlement x cw), and rostral carapace length in the had grown to such proportions that they shrimp (rei) measured with dial calipers were indistinguishable from other older to the nearest 0.1 mm. colonies already present.

Qualitative Faunal Survey Gut Content Analysis of Selected Decapod Species A qualitative faunal survey of decapod and stomatopod crustaceans on, or in the Gut content examinations were performed vicinity of, worm reefs at each station was on the six most abundant species overall, maintained concurrently with the quantita- as determined by Quantitative Survey. As tive survey throughout 1974. It was stopped far as was feasible, adult and juvenile male in April 1975 when it appeared that nearly and female specimens collected during the all species being collected were previously Qualitative Survey were used. These in- recorded. Macrocrustaceans were collected cluded individuals collected during both the by hand, either from the adjacent sandy warm-wet (May-October) and cold-dry beaches, or in the surf zone sandy sub- (November-April) seasons in central Flori- stratum, as well as from large coalesced da. The entire stomach was excised and worm colonies at each station. The former examined under a binocular dissecting mi- provided species of decapods such as ghost croscope. Identifiable, large food particles crabs, sand crabs, or mole crabs, which are were catalogued according to their estimated found in proximity to, but do not actually percent of occurrence in the entire gut con- inhabit the worm reef heads. The latter tents. Microparticles were identified and provided a more complete inventory of spe- catalogued as above from smear slides ex- cies which either inhabit or may, from time amined under a higher powered compound to time, occur on the sabellariid reefs. Large microscope. The results are presented in adults of several worm-reef inhabiting spe- Table 3. 228 BULLETIN OF MARINE SCIENCE, YOLo 28, NO.2, 1978

•...8 o 9:

++++++ ++++++ --- '-' '-' '-' --... '-' '-' '-' '-" '-' '-' --- OIl O~ON""'OO " .§ ******Nt"f"I\Ot"--.,...... j~ 'E :B <':S E" ..c:: c .5 "

'0 o C. «l <.I <1) '0 .•... o

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z "'"00 <'> V) N ,...;I~ N 00 00 ,...;N V) liEl GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 229

Physical and Physiographic Parameters on Worm Reefs in the Study Area 30 39 All the reefs in our investigations were 37 located either in the shallow-water surf zone 35 directly off wide, sloping, sandy beaches 33 (St. Lucie Inlet, Walton Rocks), or just 14 31 inside the mouths of dredged and main- tained navigable inlets which connected the 30 39 Indian River lagoon with the Atlantic Ocean :" 26 U 37 (Ft. Pierce and Sebastian Inlets). As a -- 22 35~ ••• .-. consequence, all reefs were exposed to wave llI: 18 33~ action from the open sea, although reefs at :J :;: 14 31 Walton Rocks and 8t. Lucie Inlet probably Walton Rocks > llI: ... received more breaking surf because they ••• Z faced directly into the open sea. All the ~ 30 39 reefs in the geographical area of this study ~ 26 37~ Vl generally experienced a similar salinity and 22 35 temperature regimen as these parameters, 18 33 both on wave-exposed shores and in the 14 31 inlet mouths, underwent approximately the Fl. Pierce: Inlel same daily range of variation. The annual 30 39 salinity and temperature range (Fig. 4), ob- 26 , 37 tained from measurements made at each 22 , 35 ,, station during field collections, did not vary 18 33 significantly (one way ANOVA) when all \ 14 ~ ~~ 31 stations were considered, and were indicative .• Sebostlan Inlet IFMAMJ J ASOHDJfMAMI JASOHO of values of surf zone waters in the Indian 1974 1975 River area. Tidal variation both in am- plitude and time was nearly identical Figure 4. Annual fluctuation of temperature (CO, throughout the 80 km area from Sebastian solid line) and salinity (S%o, dashed line) on sab- ellariid worm reef stations. See text for further Inlet to $t. Lucie Inlet (mean values of discussion. variation HW = 0.2 ft, 4.6 min; LW = 0.0 ft, 6.8 min; for all stations). Both the substratum and sediments available for reef which occurred on selected worm reef heads. construction were similar over the geo- Relative abundance of species within a sta- graphic range of the study. The former was tion was expressed by dividing the number primarily semi-exposed coquinoid limestone of individuals of a species on each sampling ledges of the Anastasia geological formation; date by the total number of individuals of all the latter consisted of fine calcareous sand species from that station. Between-station (35-50%) and quartzite-silica sand (ca. relative abundance was calculated similarly, 40%), generally ranging between 125 and but using the total number of individuals 500 porn (Kirtley, 1966, unpubl.; and Multer from all stations; both methods gave a per- centage which allowed species to be ranked and Milliman, 1967). according to the number of contained indi- viduals of each species. For this study, spe- Mathematical Analysis of Community cies were ranked in abundance with other Structure species at a given station, in their overall The absolute numbers were taken of all abundance, and in their occurrence on all the decapod and stomatopod crustaceans worm reef heads sampled from a given sta- 230 BULLETIN OF MARINE SCIENCE, YOLo 28, NO.2, 1978

tion for either 1974 or 1975. These data Stbl:~ ,/ ~~ .'_ are presented in Table 4 (Figs. 5, 6, 8). to The actual number of species (S) and ~~,.~<' z --_-- .~_.- - .... -. individuals (N) at each station is itself an lfi WI1!Y_----...... /' ---... -- ...... •.-- . \ indication of species richness and diversity. ffitO~~~ \ We restrict our consideration to the concepts OJ _~--_:::::..~--}. __ . •• _ of Sand N, and to the relative abundances ~ n.riuci -\ /" ' ...., /".- '\ ....__ -...... , _ Z 1.0 as noted above. The previous concept of o --YL\,'v -~------./'.::..:.:..~--. g- .~ .l _._ ,,__ . species diversity, using the Shannon-Weaver, .J 1.5 SlUsH...... •• Brillouin or other indices has received much 1.0 .•...... \ /- ~~_.-.:.: N = Dashed line criticism 'of late (Hurlbert, 1971; Heip and 0.5 'Vi S 1:I Solid line J FMAMJJASONDJ FMAMJJASOND Engels, 1974; Dejong, 1975; Peet, 1975) 1974 1975 so they are not incorporated herein. Figure 5. The number (Log,.) of species (8) and number of individuals (N) collected from RESULTS each sabellariid worm reef station during 1974- 1975. Vertical scale identical for all four stations. Species Composition and Numbers of Sebastian Inlet not sampled in 1975 (see text). Decapod and Stomatopod Crustaceans

A total of 105 worm reef heads were 1975, all represented by a single individual. analysed during 1974-75 for the Quantita- This suggests that a fairly complete survey tive Survey. These samples yielded 1861 of the macrocrustacean fauna inhabiting specimens of juvenile and adult decapod these worm reef heads was accomplished. and stoma topod crustaceans consisting of 51 We shall consider as common (i.e. more species in 28 genera and 13 families. The than 20 individuals collected over a 2-year concurrent Qualitative Survey provided an- period) only 10-11 of the 51 species taken other 2556 specimens, both juvenile and during the Quantitative Survey. These 10-11 adult, comprising 85 species in 48 genera species comprised about 90% of all the and 21 families. The combined data indi- individuals considered (Fig. 6). The next cated that at least 96 species of decapod 9-13 most abundant species (included as and stomatopod crustaceans in 52 genera "other", Fig. 6) accounted for 4-7% of the and 22 families, may either inhabit or live total relative abundance of all species col- in proximity to, sabellariid worm reefs in lected during 1974-75, bringing the total to the Indian River area (Appendix 1). 97%. These 20-24 species (= the first 24 The numbers of individuals and species listed for St. Lucie Inlet, Table 2) were (N, S) which occurred at each quantitative more or less characteristic of the macro- station during each month were quite vari- crustacean community on these reefs. The able (Fig. 5). More species occurred at the remaining 27 species (also included as St. Lucie and Ft. Pierce Inlet stations than "other") made up another 3% of quantita- at Walton Rocks and Sebastian Inlet (Table tively sampled individuals, and we con- 2). St. Lucie Inlet, the southernmost station sidered these uncommon. Forty species sampled, produced a total of 37 species in represented less than 10% of the quantita- 23 genera and 12 families in 1974, whereas tively sampled fauna, and 24 of these were Sebastian Inlet, the northernmost station known from three or fewer individuals over sampled, produced only eight species in five the 2-year collecting period. These 24 genera and three families during the same might be considered rare forms and six were period. Subsequent sampling in 1975 added classified as occasional associates. The 24 only a few more species at all stations. A rare forms were numerically more important total of 45 species was collected in 1974 at Ft. Pierce and St. Lucie Inlets, but never and only six more species were recorded in comprised a major part of the fauna at these GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 231

stations. Of the 17 species represented by PERC£NT TOTAL ABUNDANCE 1974·75 a single individual, 10 occurred at St. Lucie __.~2_0_..,.-_4_0_~~_60 80 100 Inlet, five at Ft. Pierce Inlet, and one each at Walton Rocks and Sebastian Inlets. Four were designated as occasional associates. ..5 Three crab species, pachycheles monilifer % ..<6 (Porcellanidae), Menippe nodifrons (Xan- ",7 ~8 thidae), and Pachygrapsus transversus U ~ 9 "'+'·~l~~~:••, (Grapsidae) composed 65% of the total "'10 ,..11 •••••••• ,"". quantitatively sampled fauna. The next three. 11 species, the alpheid pistol shrimp Synalpheus 12-51 fritzmuelleri, and the xanthid crabs Pilumnus Figure 6. Species rank and percent relative abun- dasypodus and Panopeus bermudensis, were dance of 11 common species, based on all in- also numerically important comprising an- dividuals collected during the Quantitative Survey, other 15% of the total sabellariid-inhabiting ]974-1975. "Other" refers to the remaining 40 species which collectively comprised 10% or less macrocrustacean fauna. The importance of of the total number of individuals collected. these species will be discussed in later sec- tions. A total of 76 species were taken during The total number of occasionally associated the Qualitative Survey in 1974, 40 of which species recorded from all surveys over both (53 %) had also been recorded during the years totalled 26 species, or 27% of all Quantitative Survey for that year. These in- recorded species (denoted by an asterisk, cluded 24 characteristic, 12 uncommon and Appendix 1). We suspect that, barring 4 associated species. Of the remaining 36 major change in the biotope, continued species (47 % ), 21 were classified worm reef sampling might add one or two previously inhabitants (28%). All but Calcinus tibicen unrecorded species each year. were represented by five or fewer individu- als in 1974. The 15 remaining species Distributional and Reproductive Seasonality (20%) were considered to be occasional in Sabellariid-Inhabiting Decapoda associates, using the following criteria: On the average, about 60% of the 24 eight (11 %) occurred predominantly in the characteristic decapod species could be col- lagoonal grassbeds; three (ca. 4%) were lected during any given month; 80% during usually found offshore (Penaeus sp., May, July, or August of either year, 60% to Sicyonia dorsalis, Portunus gibbesi); three 75% in January, February, June, October, were sandy beach intertidal species (Arena- and December. It is reasonable to assume, eus cribrarius, Emerita talpoida, Lepidopa therefore, that the more abundant members henedicti); and one was a sandy beach of the macrocrustacean community inhabit supralittoral species (Ocypode quadrata). Indian River worm reefs more or less The Qualitative Survey in 1975 yielded throughout the year, including the coldest only nine species previously uncollected in winter months of December through Feb- any survey. Five of these were worm reef in- ruary when ocean temperatures may drop habitants (Alpheus peasei, Cronius ruber, to 18°C, and lagoonal waters to 14°C. Macrocoeloma subparallelum, Micropros- Data from our Faunal Surveys, and pre- thema semilaeve, and Synalpheus d. cura- vious collections made on Indian River caoensis), each represented by one or two worm reefs, indicate that three of the most specimens. The remaining taxa included abundant species, Pachycheles monilifer, three offshore species (Metapenaeopsis Pachygrapsus transversus, and Synalpheus goodei, M. smithi, Panulirus argus) and the fritzmuelleri, breed year around. Pilumnus terrestrial land crab Gecarcinus lateralis. sayi and Petrolisthes galathinus breed from 232 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

through August. If winter temperature 30 minima are affecting egg production, it is 28 not readily apparent in at least 10 of the 26 (f) characteristic species, nor in four of the 10 UJ 24 most abundant decapod crustaceans on &J22 central Florida worm reefs. 8po 018 Similarity in Macrocrustacean Species ~ 16 Composition among Stations « 14 I (f) 12 While similarity in species composition

~ 10 among the quantitative stations implies ll:: 8 similarity in habitat (excluding latitudinal gradients from consideration at this time), III 6 ._._.~~~c:-.!~!!1!!...lcl~.!. / ~ 4 ,/ the antithesis is not necessarily true, as our :J /~ - -'- Z 2 data reveal. St. Lucie Inlet was the most species rich 2 4 8 12 16 20 24 28 CUMULATIVE SPECIES NUMBER station (Table 2), so the numbers of species collected during quantitative sampling here Figure 7. Comparisonof the cumulativenumber were plotted cumulatively by rank, and then of speciesand number of speciesshared, among the sabellariid worm reef stations during 1974- co-occurring species shared by the three 1975. The St. Lucie station,with the most species, more northerly stations were compared with was held constant and the cumulativelyco-occur- St. Lucie species, as each was recorded ring speciesfrom the remainingthree stations to (Fig. 7). At Ft. Pierce Inlet, more species the north were plotted againstthe St. Lucie Inlet Hnorm.H occurred in common with St. Lucie Inlet (22 of 39 species, or 56%) than occurred at Walton Rocks (19 of 39 species, or January to at least August. Ovigerous fe- 49% ). showing that the two more southerly males of both Menippe nodifrons and Pilum- inlet stations were more alike both in spe- nus dasypodus occur from May through cies composition and in the numbers of August, and Panopeus bermudensis spawns co-occurring forms than was Walton Rocks from at least May through October on these station, located between them. The species reefs. Data are incomplete for Mithrax not shared among these stations, four at coryphe, and Menippe mercenaria occurred Walton Rocks and eight at Ft. Pierce Inlet, only as juveniles on the reefs. Thus, at were numerically unimportant forms (= least 50% of the most common species can "rare species") comprising approximately be ovigerous during the coldest months of 1% or less of the total number of individuals the year in the Indian River area (Decem- recorded from quantitative sampling at each ber-February). Winter breeding data for of these stations. other species include Alpheus nuttingi Sebastian Inlet reef, physiographically (November-August), Alpheus formosus similar to the southern reefs, was the most (J anuary-J uly), Synalpheus townsendi (J an- depauperate area quantitatively, and shared uary-August), Epialtus bituberculatus (Jan- only five species of the 39, or 13% (Fig. 7). uary-August), and Alpheus thomasi This station also supported only four of the (J anuary probably through August). Fur- 20-24 characteristic species of Quantitative ther collections may prove these species to Survey, and exhibited an unusual abundance be year round breeders too. Limited data of one common species, Pachygrapsus trans- on Pagurus carolinensis, Calcinus tibicen, versus, followed by a lesser abundance of and Plagusia depressa, indicate breeding at Menippe nodifrons (Table 2; Fig. 8). Two least through the summer months of May of the remaining four species collected GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 233

quantitatively at this station, Panopeus as the quantitative study suggests, although herbstii and P. occidentalis, did not occur in relative abundance, and to some extent elsewhere during our Quantitative Survey. compositionally, it differs from southern These two species are apparently estuarine stations. However, it should be remembered immigrants onto the worm colonies at Se- that Qualitative Faunal Survey data in- bastian Inlet. Both species of Panopeus are creased species-richness at the more south- extremely common in the grassbeds and erly stations too. Quantitatively, Sebastian oyster bars inside the Indian River lagoon, Inlet is still less species-rich than these sta- directly to the west of the inlet (Gore, un- tions, as the mean values for numbers of pubI. data), and neither species is common species and individuals collected there elsewhere in the Indian River area except in (Table 1), and the total number of species the estuarine habitats of the lagoon. obtained (Table 2) attest. During the Qualitative Faunal Survey, 34 species of decapods were collected from the Relative Abundance and Occurrence of Sebastian Inlet area, but only 20 of these Macrocrustaceans among Stations were found on worm colonies. All 20 were Relative numerical abundance of a species previously taken from southerly quantitative may be a possible indicator of ecological stations and were properly designated worm dominance by that species in a community. reef inhabitants. However, 16 of these 20 Seven of the common species were recurrent species were known from 10 specimens or when ranked according to their relative fewer, and 10 species were represented by abundance at all stations; Panopeus ber- only one or two individuals, so all were mudensis and Pilumnus sayi assumed dif- relatively less abundant here. The first and ferent rank order between 1974 and 1975 second most abundant species in our Quali- (Table 4). However, only the three most tative samples were Pachygraspsus trans- abundant species, Pachycheles monilifer, verSl/S and Menippe nodifrons, respectively, Menippe nodifrons, and Pachygrapsus trans- the same two species ranked as such in the versus retained the same order of rank Quantitative Survey for this station. Only during the 2-year study. Moreover, the per- three specimens of Pachycheles monilifer, two males and a female, were taken here centages for all species were similar for both years, and in the three most common varied during the entire Qualitative Survey, and by only 2-3%. none were collected during the Quantitative The seven recurrent species were numeri- Survey. These data will be reconsidered in cally important both within, and between, the section on trophic relationships. their respective stations, although the order Of the remaining 14 species classified as of numerical dominance was not consistent occasional associates at Sebastian Inlet, 11 from 1974 to 1975 (Fig. 8). For example, belong to the lagoonal estuary (including within the St. Lucie Inlet station the ranked two rocky shore species, Mithrax forceps relative dominance of Menippe nodifrons and M. verrucosus), one to the sandy beach changed from first in 1974 (22% of all in- sublittoral (Emerita talpoida), and two to dividuals collected at this station belonged the offshore continental shelf (Sicyonia to this species), to third in 1975 (17% of dorsalis, Portunus gibbesii). Ten species were all individuals were this species). Similar represented by six or fewer specimens. variation in abundances were seen in other Excluding the mole crab Emerita, which species, but the role of the three most com- forms large assemblages in the surf zone, mon is again evident. the two most abundant occasional associates The seven species were ranked according were the xanthids Panopeus herbstii and P. to the percentage of worm colonies on which occidentalis. they occurred at each station, and on the Sebastian Inlet is thus not as depauperate percentage of total worm colonies sampled 234 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

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St. Lucie Walton Rocks Ft. Pierce Sebast ian

1974 (DAY)

.Pachycheles monilifer DMenippe nodifrons 1975 IIIlPachygrapsus transversus (HIGHT) DSynalpheus fritzmuelleri .Pilumnus dasypodus IIIMenippe mercenaria miliPanopeus bermudensis

Figure 8. The percent relative abundance based on the total number of individuals of seven recurrent species collected from each station during 1974-1975. Numbers inside the circles indicate the percent of the total fauna within each station that the individuals of seven recurrent species comprised. Sebastian Inlet station eliminated during 1975 (see text). in each year. The three most common spe- be seen, but no between year comparisons cies again assumed importance (Table 4). on species occurrence can otherwise be Menippe nodi/rons was found on a higher made. percentage of colonies both within-station The data presented on relative abundance and overall than was any other species. and occurrence indicate that seven species Pachycheles monili/er ranked second (1974) are numerically dominant in the macro- and third (1975) in overall occurrence even crustacean community. These species, which though it was numerically the most abun- make up the majority of individuals on the dant species, ranking first in numbers of reefs (up to 88% of all quantitatively col- individuals in both years. Pachygrapsus lected specimens), are thus an important transversus increased slightly in occurrence faunal component in the sabellariid biotope. on colonies within-station from 1974 to Similarity in rank order both for relative 1975, but its overall occurrence on all numerical abundance and percent occurrence colonies did not change significantly during on worm colonies in 1974-1975 indicates the 2 years (one way ANOYA). The most that little change took place either in relative notable change in rank order for within- species distribution or relative abundance station occurrence took place at Ft. Pierce during these 2 years. The observed con- Inlet in 1975, where Pilumnus dasypodus, sistency in species composition, relative although numerically less abundant than P. abundance, percent occurrence, and the monilifer, was nevertheless found to occur numerical dominance of the recurrent spe- on the same percentage of worm colonies cies, if applicable to the remaining macro- at this station. Panopeus bermudensis also crustacean assemblage, implies that the showed a higher occurrence than in the pre- community as a whole possesses a marked vious year. The overall numerical rank, stability on the sabellariid bioherm. based on the percent occurrence of these The numerical dominance of Pachycheles species on all worm heads remained stable monilifer, Menippe nodifrons, and Pachy- for both 1974 and 1975. The depauperate grapsus transversus suggests that they might nature of the Sebastian Inlet station can also also be ecologically dominant among the 236 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978 sabellariid macrocrustacean fauna. We can however, are predominantly lagoonal species consider these three species as a species in the Indian River estuary and are rarely "hierarchy" in the sense that they represent collected on the sabellariid biotope. More- the most numerically dominant forms in a over, M. nodijrons is only rarely collected graded series. in the Indian River lagoon, so that the two species, while sympatric, are biotopically ex- Species Composition, Relative Abundance clusive as adults. All of the other common and Occurrence of Decapoda on New species so far discussed are found in the Sabellariid Colonies sabellariid biotope both as juveniles and adults and, with the exception of Pachy- The three species in the hierarchy were grapsus transverslls, are quite uncommon in found on the newly settled sabellariid the lagoonal estuary. colonies studied from March to August 1975. No decapods were found on the Gut Content Analysis in Six Species of newest settlement in March. The total sur- Decapod Crustaceans (Table 3) face area of this small flattened colony was only 54.6 cm2 and no crevices were yet The numerically most abundant decapod present. Decapod colonization on increas- species in the sabellariid biotope, Pachy- ingly larger, topographically more complex cheles monilijer, is a suspension feeder. A worm reef heads was initiated in April by small crab (in our study maximum cl = Menippe nodijrons, followed in May by 10 mm), it feeds by using specially modified Pachycheles monilijer and Synalpheus third maxillipeds as food nets, to sweep the jritzmuelleri, and in July by Pachygrapsus suspended material and plankton which is transversus. All initially colonizing decapods found in the surf zone water column. Its were juveniles from 1.4 to 3.9 mm cl. trophic level is therefore similar to that of Menippe nodijrons occurred on 60'1'0 of all the polychaete constructor of its substratum, the sampled newly settled colonies during although food particle size may be different. March to August, while P. monilijer and Identifiable gut contents in the crab con- P. transversus were found on 50'fo and 30'fo sisted primarily of microcrustacean setae of these colonies, respectively (Table 4). and antennae, some Phragmatopoma palae The early colonization of what, in effect, and uncinae, as well as diatoms and sponge are sterile islands, was thus accomplished spicules. Sand accounted for 20-50'fo of by the same three or four species of decapod gut contents and undoubtedly reflects the crustaceans that proved to be numerically turbulent conditions of the surf zone. and distributionally abundant on the more The second most abundant species, mature worm colonies. Menippe nodijrons, grows quite large (cl A second species of Menippe, M. mer- max. = 88 mm) and, like other members of cenaria, assumed some relative importance by the Xanthidae, is a predator. This species occurring on a higher percentage of the de- feeds on Phragmatopoma lapidosa (Kirtley, veloping worm reef heads which were 1966, unpubl.) as well as on other members sampled than did Pachygrapsus transversus, of the sabellariid biotope fauna, including although the former species always remained molluscs, amphipods, isopods, and sponges. numerically less abundant than the latter Several larger individuals contained large, during this period of the survey. Our field undigested fragments of Pachycheles moni- data indicate that both juvenile and adult lijer, suggesting that the latter species is Menippe nodijrons are found on sabellariid important in the diet of Menippe nodijrons. reefs, whereas M. mercenaria occurs thereon Pachygrapsus transversus, the third most primarily as juveniles, rarely exceeding abundant species, is a small (cl max. = 20-mm cl. The adults of M. mercenaria, 15 mm), omnivorous, grapsid crab which, GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 237

MENIPPE _~ NODI FRONS _15'- - 2/2f !

PACHYGRAPSUS TRANSVERSUS 16,;' ~ Pilumnus 17 "/ dasypodus ~ 19 II Synalpheus 39 ?? 6#' fritzmuelleri Phytoplankton 27~Panopeus " bermudens~\ ~ PHRAGMATOPOM,A; ~ 16 [ Zoopl.oktoo ~.tAPIDOSA",,?

~ Worm Larvae /;ff? ?~ ~ & Fragments ~, ~ // A OIl Fecal matter ••.••./ mphipoda,lsopoda % / ~~c~-~c=?-~-~- ~ Mollusca,Porifera loetritus /--== ----

Figure 9. The trophic sub web postulated for the six most abundant species of decapod crustaceans on central Floridan sabellariid worm reefs. The numbers on the lines indicate the percent of observed prey material noted in the gut contents from all combined individuals of a species. Trophic lines without numbers, or with question marks, are interpolated from our field observations or from records in the literature. Dashed lines indicate production from Pliragmatopoma lapidosa.

on the sabellariid reefs, seems to be pri- nus dasypodus is more of an herbivore than marily a scavenger, eating diatoms, algae, the other two species, showing preference Phragmatopoma operculae, body fragments, for diatoms and algae (Table 3). setae and palae, as well as microcrustaceans Because the six species considered here such as amphipods, isopods, and on occasion are all carnivorous to some extent, com- other Pachygrapsus. petition for food might be expected. How- The next three species in relative abun- ever, the three most abundant species appear dance, the pistol shrimp Synalpheus fritz- to avoid competition by a restriction in muelleri, and the xanthid crabs Pilumnus trophic levels; viz. suspension feeding, dasypodus and Panopeus bermudensis, are benthic directed predation, and by omniv- also small species (cl max. = 8, 9, and orous scavenging, respectively. The postu- 5 mm, respectively), which appear to be lated food subweb is illustrated in Figure 9. omnivores and facultative predators or scav- Our data also show that all six species engers. All feed to some extent on are able to utilize the sabellariid worm as a Phragmatopoma lapidosa, and on members food item (Table 3). In most cases, they of the biotope fauna, including amphipods, feed directly on the polychaete or, as seen isopods, small molluscs and sponges. Pilum- in Pachycheles monilifer, on body parts 238 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

suspended in the water column. Feeding on islands, found stabilization of species num- sabellariid larvae, postlarvae, and even fecal bers and an implied trend toward constant material may also be important to these species composition although in her investi- species, especially P. monilifer, although we gation the species were numerically coded could not distinguish these items in our gut rather than named. content analyses. However, Gruet (1973) Paine (1969) has succinctly defined noted that some members of the decapod stability as the integrity of the community fauna associated with reefs formed by Sabel- and its unaltered persistence through time. laria alveolata (L.) , a European species, In the following discussion we postulate that were capable of feeding in this manner. the sabellariid associated macrocrustacean Obtaining food would not seem to be a community consists of a compositionally problem, then, for the six species of decapod similar species assemblage able to persist crustaceans, and possibly for others, on over at least a 2-year period without major healthy Floridan sabellariid worm reefs. change occurring. This persistence stability Nutrition can be obtained above the biotope may be due to several factors, each of which (suspension feeding), within the biotope will be considered below. These are (1) (interspecific predation) or on the biotope persistence of the sabellariid biotope, and (feeding on the worms themselves). the relative consistency (but not constancy) of environmental conditions associated with DISCUSSION it; (2) trophic partitioning among the most common species; (3) a possible predator- The concept of community stability has prey relationship between two of the top been expressed in several different ways three species; and, (4) a correlation between (MacArthur, 1955; Margalef, 1968; Holling, the zoogeographic ranges of the two most 1973; Peterson, 1975) and differentiation abundant decapod species and that of the has been made between persistence stability, sabellariid worm itself. In addition, a brief and adjustment or resilience stability. The comparison between species composition and latter two concepts measure a given com- relative abundance of decapod crustaceans munity's ability to adjust to, or withstand from other sabellariid worm reefs, with those perturbation (either man-induced or natu- studied in this report, demonstrates simi- ral) which produces changes in species com- larities between these biotopes. position or abundances, and to return to the original state of the community. Persistence Persistence in the Sabellariid Biotope and stability, on the other hand, measures the the Macrocrustacean Community constancy of a given community over a period of time, although such constancy it- The sabellariid reefs, like coral reefs, arc self may be the result of the ability of the a complex biotope forming a living, more or community to adjust to or resist environ- less uniform, substratum. The sabellariid mental change (Peterson, 1975). Among worm reefs in the Indian River region of the requisites which have been used in the Florida have an additional importance for consideration of persistence stability are they form a hard, quasi-permanent, sub- consistency of numbers of individuals per stratum that allows a typical associated fauna given area, and constancy in numbers of to occur in a high energy surf zone without species. Lie and Evans (1973) also em- having to contend with a constantly shifting phasized the importance of constant species sandy sea floor. Moreover, these reefs form composition in a study on long-term vari- an edible and usually replenishable sub- ability of benthic communities in Puget stratum in themselves. Sound. Amy Schoener (1974) in an experi- All the reefs in this study were constructed mental study using artificial sponges as by the same species of worm, Phragma- GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 239

topoma lapidosa. All were identical in over- the repetitious warm-wet, cold-dry sea- all construction, exhibited approximately the sonality may be the more influential param- same morphological form, and grew in a eter for the macrocrustacean species on the similar manner (i.e. by lengthening of tubes reefs. through accretion of sand particles by the Our field observations over 2 years have worms at the surface of the colony). The indicated that the sabellariid biotope, in species composition of the macrocrustacean general, is well able to withstand the re- fauna on these reefs is therefore probably current, seasonal (i.e. long term, slow) due in some measure to the observed simi- variations which occur. The persistence of larity in reef physiography, as well as in the the biotope would 'thus allow stability in the overall physical environment to which the associated communities to develop, especially species are exposed. Other faunal associates if the community consists of species whose notwithstanding, the fact that at least 51 distributional occurrence and reproduc- species of decapods and stomatopods were tive seasonality either seem unaffected by found in quantitative collections from a the environment, or are able to tolerate habitat, the surf zone, where they would not short-term variations in either the biotope normally OCcur except for the presence of or the surrounding environment (as would hard, relatively secure substrata, dramati- seem more likely) . cally emphasizes the importance of the The general biology of the sabellariid sabellariid reefs for these species. More- worm may also have an indirect influence over, as our gut content analysis showed, at on community development and stability. least six of these crustaceans feed directly Studies by Ecklebarger (1976) on the worm on the sabellariid worms, and on the as- reefs at St. Lucie and Walton Rocks have sociated cryptic microflora and fauna as indicated that the larval development of well. They thus utilize a readily available Phragmatopoma lapidosa may be as short food source in what would normally be, to as 14 days, and that sexual maturity may all but suspension-feeding invertebrates, a follow metamorphosis in as little as 6 weeks. food-poor environment. Eckelbarger suggested that on these reefs Physiographic and physical conditions on spawning may be a year round event, a all worm reefs in the 80 km geographical situation we had noted in some species of range encompassed by this study were decapod crustaceans found there. Major nearly identical. Tidal variation and weather- settlements of larvae could occur at least induced wave action may also be considered three times a year. These newly metamor- similar for each area. The climate of the phosed larvae can settle on older, or dead, Indian River region is subtropical with a worm colonies, thereby increasing the size distinct warm-wet season (May to October) and topographical complexity of the biotope. alternating with a cold-dry season (Novem- They may also settle on plain coquinioid ber-April). Regionally heavy rainfall with limestone plates, as did those we studied resultant salinity depressions occur during the warm-wet season; these conditions are from March to August 1975, with the same most notable at inlet stations, behind each of end result, i.e. increased topographical com- which on the western bank of the lagoon plexity of the biotope. exist rivers or large flood control canals The sabellariid worms are also able to (Figs. 1 and 4). Salinity and temperature quickly repair damage to their colonies. curves show distinct minima; the former in Abrasion by shell particles, destruction by July 1974, and June-July 1975, the latter drifting logs, minor erosional-induced col- in December 1974 and February 1975. lapse, and even damage due to human foot- Variation in important marine parameters prints (Kirtley, 1966, unpubl.) or vandal- of salinity and temperature is apparent, but ism, may be indiscernible on these reefs a 240 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

few days after it occurs. Persistence of the corollary to the presence of "large" numbers biotope is still further enhanced. of species may therefore not be as important In summary, distributional and reproduc- when it can also be shown that at least tive data, as well as that from relative some of the numerically most abundant taxa, abundance and occurrence, seem to support besides being able to feed on each other, the hypothesis of persistence stability in the have an alternate and usually available food 20-24 characteristic species, representing source. In this case the food source is the 90-97% of all collected individuals in the sabellariid bioherm itself. There may be less decapod community. Predictability, indicated need for resource partitioning and perhaps a by recurrence in species and similar relative greater need for trophic restrictions, as we abundance, was more evident in seven of will discuss next. the 10-11 common species, while the most consistent numerical dominance was ex- Trophic Partitioning and Biotope hibited by the first three species, the hier- Specialization by the Macrocrustacean archy. The remaining 27 species may also Community have exhibited persistence, but because so Resource partitioning has been defined as few numbers were collected we can make no the different ways that species in the same conclusions concerning them. Whatever ex- community utilize resources (T. Schoener, tinction or immigrative colonization of 1974). The most common category is macrocrustacea that is occurring is probably habitat-food type partitioning, which refers taking place in these 27 species which con- to the manner by which different competing tain 4% or less of the total numbers of species, usually (but not always) in the collected individuals in the community but same genus, and occupying the same habitat, comprise more than 50% of the total species utilize available food items. composition. We could not demonstrate habitat-food MacArthur (1955) pointed out that type partitioning in the common macro- stability in a community can be achieved crustaceans. The three most abundant crab either through large numbers of species species on the worm reefs belong to three which are restricted in their diets, or con- different genera, utilize three different modes trarily, by a smaller number of species in of nutrition, to obtain three generally dif- which each eats a variety of the other spe- ferent types of food. The next three species, cies present. The terms "large" and "small" an alpheid shrimp and two xanthid crabs, are, of course, purposely vague and imply were more generalized in their nutritional relative numbers. The 51 species collected during the Quantitative Survey, most of modes. The essential activity occurring in the first three crab species is not, therefore, which inhabited the more southerly reefs, direct competition with each other for the are a large number of species when com- pared with the two decapod species found in same food resources, but rather a partition- the adjacent sandy beach supralittoral on ing of nutritional modes in the habitat by the one hand, and the four decapod species restriction in trophic levels. We will use of the nearshore sandy sublittoral benthos the term "trophic partitioning" to describe on the other. Whether these large numbers this activity. of species are restricted in their diets is Adaptation to substrate is also important another matter, as our gut content analyses in determining the composition of decapod has shown. It would appear that many of species in a biotope as Abele (1974) has these species are more likely to feed on each shown. Numerically dominant taxa are other or the cryptic worm reef fauna, thus usually specialized morphologically in some sharing food resources among each other. way to aspects of their environment. Sandy MacArthur's restriction of diet as a necessary beach species may possess specialized GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 241 mouthparts for suspension-feeding; rocky Synalpheus, Pilumnus and Panopeus con- shore species may have modified append- sisted primarily of microcrustacean body ages such as spoon-shaped chelipeds for parts, polychaete worm fragments, plant scraping algae, and so forth. Abele also material and detritus (Table 3). Predation noted that marine decapod crustaceans use by these species on larger forms would substrates in three major ways: (1) for seem to be excluded, although the decapods shelter; (2) as a feeding site; and (3) as a themselves may become prey to larger spe- source of nutrition. cies such as Menippe nodifrons. The ninth Data obtained during this study are in and tenth ranked species, also small forms agreement with Abele's findings. The 51 (10-20 mm cl), are an herbivore and sus- species taken during quantitative collections pension-feeder, respectively. utilize the worm reefs as a hard substratum. It seems obvious that these species may also Postulated Predator-Prey Relationships use the sabellariid reefs for shelter. Data among the Hierarchy Species from gut content analyses indicate that at least six of these species may use the worm The most species-rich families on the reefs as a feeding site (for predation, sus- worm reefs were the xanthid and majid pension feeding, or grazing), and as a source crabs. The former family accounted for five of nutrition as well, by feeding on the of the most numerous species and 36% of sabellariid worms themselves. While limited all collected individuals in the quantitative partitioning of food resources may occur in study. The majids comprised only two of the alpheid shrimp and two xanthid crabs the common species and 6% of the total which appear to be generalized omnivores, number of individuals. The Xanthidae may the three most abundant species avoid com- thus be disproportionately important eco- petition by trophic partitioning. Thus, logically as predators, although individually (except Menippe nodifrons) they were not Pachycheles monilifer seeks shelter from predation in worm reef crevices, uses the as numerically important as some other worm reef as a feeding site, and feeds, specIes. albeit indirectly, on sabellariid worm parts suspended in the water column by wave Menippe nodifrons as a Predator in the action. Menippe nodifrons can excavate Sabellariid Biotope large burrows in the friable worm reef sub- Menippe nodifrons is the largest decapod stratum, and forages over the reef feeding crustacean actually inhabiting the central either on the associated fauna or the worms Floridan worm reefs. The species is a forag- themselves. Pachygrapsus transversus hides ing predator able to excavate large holes or in crevices on the reef, ranges freely over "caves" in the sabellariid reef as a result of the biotope and feeds on a variety of plant feeding activities either directly on the poly- and animal material, as well as on the chaete worm or on the cryptic associated sabellariid worms (Table 3). These three species have different nutritional modes, i.e., fauna of the reefs (Kirtley, 1966, unpubl.). suspension-feeding, benthic-directed carniv- Because of its excavatory ability there would ory, and benthic-directed omnivory, re- appear to be no real sanctuary for the slower, spectively. Each seems to be mutually cryptic fauna inhabiting the crevices of the exclusive among the three species involved. worm colonies. The large size of adult M. It may be significant that the species ranked nodifrons, and the relative numerical domi- fourth to eighth, all of which appear to be nance of the species make it seem unlikely omnivores and facultative predators, are all that any other decapod predator would con- small forms of approximately equal size stitute a major threat to the species. None (ca. 5-15 mm cl). Gut contents in of the five other macrocrustaceans investi- 242 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978 gated for gut contents gave evidence of collected on these reefs. Fifth, Pan ope liS predation on Menippe nodifrons juveniles. bermlldensis and Menippe mercenaria oc- Pachycheles monilifer and Pachygrapsus curred in some relative abundance. Adults transversus do not form burrows so both of the former are approximately the same species might be susceptible to predation by size as juvenile M. nodifrons and M. mer- M. nodifrons. Both are somewhat cryptic cenaria. It would thus seem that Pachy- species, but Pachycheles is slow-moving and grapslls transversus has attained a greater much less agile than Pachygrapsus. The measure of ecological success at Sebastian latter may be found inside Menippe excava- Inlet by being less restricted in its diet, per- tions along with Pachycheles moniZifer, but haps being in less competition for the same the grapsid crab is more commonly collected food items as the xanthid crabs, and by as it wanders over the surface of the worm being better adapted in speed, agility, and colonies. Because of its speed and agility it size to avoid predation by the xanthids. The is probably less important as a prey item presence of only a few, large, carnivorous (if at all) for M. nodifrons than the slower immigrant decapods, plus the low relative P. monUifer. The presence of the latter spe- abundance of an otherwise successful worm cies in gut contents supports this idea. reef species (M. nodifrons) at Sebastian Pachygrapsus transversus appeared as a food Inlet, suggests that Paine's (1966) concept item only in the gut of another P. trans- may provide at least one explanation for the versus, never in any M. nodifrons that we abundance of Pachygrapslls transversus. examined. In summary, the data obtained from gut content analyses, relative numerical abun- Pachygrapsus transversus as an Omnivore dance, percent occurrence on collected worm in the Sabellariid Biotope colonies, and within station abundance, all indicate that Menippe nodifrons is the domi- We suspect that the relatively large nant carnivorous decapod crustacean on all abundance of P. transversus on all the reefs, Indian River sabellariid reefs except Sebas- and especially at Sebastian Inlet, is due in tian Inlet. There, the omnivorous Pachy- part to its omnivorous mode of nutrition. grapsus transversus is dominant. Menippe Omnivory implies less restrictions and nodifrons may also be the most important greater diversity of food items in a diet (see invertebrate predator on the numerically Table 3). In addition, Paine (1966) has most abundant species on these reefs, Pachy- suggested that an ecosystem may not be able cheles moniZifer. No other macrocrustaceans to support carnivores when the rate of were ever observed feeding on P. monilifer energy transfer to their (higher) levels is in our two years of sampling, and during insufficient. Several reasons suggest that numerous previous side trips to these reefs. such a situation obtains at Sebastian Inlet. Nor did we find evidence of P. monilifer in First, the only station where P. transversus the gut contents of four other co-occurring, was considerably more abundant than M. carnivorous/ omnivorous decapod species. nodifrons was at Sebastian Inlet. Second, only three specimens of Pachycheles moni- lifer were collected there, reflecting a nearly Zoogeographical Considerations of the Sabellariid- Inhabiting Macrocrustacea total lack of a food item seemingly im- portant in the diet of M. nodifrons. Third, The polychaete worm Phragmatopoma the predatory, lagoonal-estuarine xanthid lapidosa is a tropical species not known to crabs Panopeus herbstii and P. occidentalis occur farther north than Cape Canaveral, occurred on the worm reefs there; both are near the northern terminus of the Indian Riv- similar in size to M. nodifrons. Fourth, no er region. The strictly tropical decapod crus- adult M. nodifrons was ever observed or taceans, consisting of those species whose GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 243 most northerly continental distribution is Only Pachygrapsus transversus, Menippe the marine waters in the vicinity of Cape nodifrons, and Panopeus bermudensis were Canaveral, comprised about 43% of the collected in any numbers on worm reefs at species collected quantitatively. These in- Sebastian Inlet, the most northern area con- cluded both the common and uncommon tinuously sampled in 1974. These three species, all of which belong to the West species comprised 64'10, 21%, and 4%, re- Indian faunal component. The remaining spectively, of all collected individuals and species (57'70) have ranges which extend at ranked first, second and fourth at the sta- least to Cape Hatteras, North Carolina; tion (Fig. 8). Limited observations on a two of these species are more or less cos- small, degraded worm reef at Canova Beach, mopolitan in range. just north of Melbourne, some 50 km (30 The two most common species, Pachy- miles) north of Sebastian Inlet (Fig. 1), cheles moniLifer and Menippe nodifrons, both showed that only Pachygrapsus transversus, members of the tropical West Indian fauna, Plagusia depressa (both cosmopolitan spe- reach their general northern limit of dis- cies), and two juveniles each of Menippe tribution in the Indian River area, and have mercenaria and M. nodifrons, were present. been collected in this region almost ex- The majority of tropical species are thus not clusively on the sabellariid reefs. Their being replaced by warm-temperate forms general occurrence and distribution along on the worm reefs as one proceeds north- the central eastern Florida coastline seem~ ward. to follow that of the polychaete worm itself. These data, in conjunction with those Other common species are not as re- presented earlier on predator-prey relation- stricted. Pachygrapsus transversus, the third ships, indicate that at least two of the most most common species, is considered to be a common species appear to be both eco- cosmopolitan crab. It has been collected in logically and zoogeographically reliant on a variety of habitats and substrata through- the sabellariid worm reefs in the Indian out the Indian River area. Two other River region. As noted, the biotope pro- numerically abundant species, Synalpheus vides a seemingly required environmental fritzmuelleri and Pilumnus dasypodus, also base from which these two species (and occur throughout this region in habitats many of the others) gain both food and other than worm reefs. The latter two spe- protection. They are also able to occupy a cies arc primarily, but not restrictively, habitat capable of being exploited otherwise tropical and range northward into the warm- by only a few sandy beach supralittoral or temperate Carolinian faunal subprovince. sublittoral decapod species. They arc thus members of what Briggs (1974) calls the "eurythermic tropical" Comparison of Macrocrustacean component of the Antillean faunal province. Communities on Other Sabellariid Reefs A sixth species, Panopeus bermudensis, ap- How similar is the decapod community pears to be another strictly tropical West just considered with those seen on other Indian crab, with the Indian River region sabellariid worm reefs? The more impor- of Florida as its northernmost continental tant studies of sabellariid reefs, where it was distribution. It has so far been collected in possible to rank species, have been sum- this region only on sabellariid reefs. As its marized in Table 5. specific name indicates, this little xanthid is On a reef constructed by Sabellaria also found farther north in the Bermudas. nanella in Brazil (Fausto-Filho and Fur- These islands, situated in the axis of the tado, 1970) the four most important species Gulf Stream, are noted for their distinctly include Pachygrapsus transversus and Men- tropical but depauperate fauna (Briggs, ippe nodifrons, whose trophic relationships 1974 ). have been previously discussed; Pachycheles 244 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

Table 5. Species ran kings for decapod crustaceans inhabiting sabellariid worm reefs in other areas of the world

------~------~ "------Species and Rank Percent Decapoda Family Mode of Nutrition BRAZIL.-Fortaleza, Ceara (Fausto-Filho and Furtado, 1970) Sabellariid: Sabellaria nane/la Chamberlin, 1919 Duration of study: July 1967 to June 1968 1. Pachygrapsus transversus 74% Grapsidae Omnivore* 2. Eriphia gonagra 7% Xanthidae Carnivorett Pachycheles rUsei 7% Porcellanidae Suspension feedert§ 3. Menippe nodifrons 5';70 Xanthidae Carnivore * 4. Alpheus bouvieri 2% Alpheidae Probable omnivore Plagusia depressa 2% Grapsidae Probable omnivoretll Panopeus sp. 2% Xanthidae Omnivore/ carnivoret Panulirus laevicauda 2% Palinuridae Carnivore/omnivoret# Decapod Crustaceans = 27% of Ihe total fauna collected on these reefs ITALY.-Lavinio (Rivosecchi, 1961) Sabellariid: Sabellaria alveolata (L.) Duration of study: October 1957 to September 1958 1. Clibanarius misanthropus 23% Diogenidae Omnivore/herbivoret 2. Pilumnus hirtellus 16% Xanthidae Omnivore/carnivore~ 3. Pilumnus villosus 12% Xanthidae Omnivore/carnivoret 4. Porcellana platycheles 11+% Porcellanidae Suspension feeder* * 5. Athanas nitescens 11% Alpheidae Probable omnivore 6. Brachynotus sexdentatus 8% Grapsidae Probable omnivore 7. Eriphia spinifrons 6% Xanthidae Probable carnivoret 8. Pachygrapsus marmoratus 4+% Grapsidae Probable omnivoret 9. Alpheus dentipes 4% Alpheidae Probable omnivoret 10. Pisidia longicornis 3% Porcellanidae Suspension feedertt 11. Xantho couchi 2% Xanthidae Omnivore/carnivore? 12. Maja squinado 1% Majidae Omnivore/herbivore? Decapod Crustaceans = 30% of the total fauna collected from these reefs FRANCE.-Baie du Mont St. Michel (Gruet, 1970) Sabellariid: Sabellaria alveolata (L.) Duration of study: Not given 1. Porcellana platycheleJ 50% Porcellanidae Suspension feeder * * 2. Pilumnus hirtellus 37% Xanthidae Omnivore/ carnivore~ 3. Carcinus maenas 11% Portunidae Carnivore~ PagllYUs bernhardlls 11% Paguridae Carni vore/ omnivore tt Decapod Crustaceans = 4% of the total fauna collected from these reefs FRANCE.-Bernerie-en-retz (Gruet, 1971) Sabellariid: Sabellaria alveolata (L.) Duration of study: November 1966 to January 1968 1. Porcellana platyclzeles 73% Porcellanidae Suspension feeder *~, 2. Carcinlls maenas 23% Portunidae Carnivore~ 3. Dynomene bidentata 2% Dynomenidae Probable omnivore 4. Pagllrus bernhardus 1+% Paguridae Carnivore/omnivorett 5. Pisidia longicornis 1% Porcellanidae Suspension feedertt 6. Pilllmnus hirtellus 1% Xanthidae Omnivore/carnivore~ Axills stirhyncllUs 1% Axiidae Probable omnivore? Crangon crangon 1 individual Crangonidae Carni vore/ omnivore:l::l: Palaemon serratus 1 individual Palaemonidae Probable omnivoret Pandalina brevirostris 1 individual Pandalidae Probable omnivoret ------• This study; t By implication with other species in the genus for which nutritional mode is known; :l:fide Crane, ]947; § Kaestner, 1970; II fide Bacon, 1971; Griffin, 1971; # fide Crawford and de Smidt, 1922; U Gruel, 1973; •• Nicol, 1932; tt OrIon, 1927; Samuelson, 1970; and :t:l: Lloyd and Yonge, 1947. GORE ET AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 245 riisei, a suspension-feeding porcellanid crab; composition on the European and Brazilian and Eriphia gonagra, a predatory xanthid worm reefs suggests that the potential for crab similar in size to M. nodifrons. Mem- relatively stable macrocrustacean communi- bers of the genus Eriphia are carnivores on ties may also exist. Detailed studies which molluscs, decapod crustaceans, amphipods, would clarify many of these points, how- and polychaetes, but are also known to eat ever, remain to be made. some algae (Crane, 1947). Studies on a European worm, Sabellaria ACKNOWLEDGMENTS aLveoLata, show that in Italy (Rivosecchi, We thank our colleagues at the Smithsonian 1961) CLibanarillS misanthropus was the Institution, Ft. Pierce Bureau (SIFP) and the most abundant species. This hermit crab, Harbor Branch Foundation Science Laboratory like others in the genus (Provenzano, 1959), (HBFL) for the many times they provided aid. possesses spoon-shaped chelipeds, suggesting In particular, we thank Dr. K. Eckelbarger and that it is an omnivore able to scrape the Mrs. P. Lindley (HBFL) for their cooperation in a joint coIlecting program, and Dr. D. W. Kirtley, benthos for food. Two xanthids, Pilumnlls Palaeontological Research Institute, Ithaca, New hirteLlus and P. villosus, occur on Italian York, for providing information on the sabeIlariid reefs and are omnivores which can feed on worms. Dr. J. S. Garth, Allan Hancock Founda- the sabellariid worms (Gruet, 1973), and tion, Los Angeles, California, confirmed our identification of some of the species. Messrs. so are classified as omnivore/ carnivore in R. G. Gilmore (HBFL) and G. Ku1czycki (SIFP) Table 5 to reflect the order of preference. provided data from their own field survey of the Porcellana pLatycheles, another important associated ichthyofauna on the worm reefs. Drs. species on Italian reefs, is a suspension L. G. Abele, Florida State University, Talla- feeder (Nicol, 1932). hassee, D. K. Young, M. K. Youngbluth, and Mr. R. Gibson (HBFL) provided advice and The same species of worm in France comments on earlier drafts of the manuscript. (Gruet, 1970) supports a similar fauna on Scientific Contribution No. 93, Smithsonian its reefs. Carcinus maenas is a predatory Institution-Harbor Branch Foundation Scientific portunid swimming crab which is known Consortium, Link Port, Ft. Pierce, Florida 33450. to feed on sabellariid worms (Gruet, 1973), whereas the equal ranked hermit crab, LITERATURE CITED Pagllrlls bernhardlls, is a carnivorous omni- Abele, L. G. 1974. Species diversity of deca- vore feeding on polychaete worms, small pod crustaceans in marine habitats. Ecology molluscs, crustaceans, and some algae 55: 156-161, 4 figs. (Orton, 1927; Samuelson, 1970). In an- Achary, G. P. K. 1971. Sabellariids as associ- ates of other invertebrates and their role in other study in France (Gruet, 1971) the the formation of benthic animal communi- suspension-feeding Porcellana platycheles ties. J. Mar. BioI. Ass. India, 1969. 1: 198- ranked first in numerical abundance, fol- 202, fig. 1. lowed by the carnivore Carcinus maenas, Bacon, M. R. 1971. Zonation and habits of the and the carnivorous omnivores Pagurus grapsid crabs Plagusia capensis and Lepta- grapslls variegatus. Tane (1971) 17: 123- bernhardlls and Dynomene bidentata. 127, figs. 1-3. Each of the communities just discussed Briggs, J. C. 1974. Marine Zoogeography. Mc- consists of a porcellanid crab suspension Graw Hill Book Co., New York. ix + 475 feeder, a carnivore (usually a xanthid crab) pp., 65 text-figs. and either a grapsid or pagurid crab omni- Crane, J. 1947. Eastern Pacific Expedition of the New York Zoological Society 38. Inter- vore among the three or four most common tidal brachygnathous crabs from the west species. This suggests that trophic partition- coast of tropical America with special refer- ing and other ecological relationships similar ence to ecology. Zoologica (New York) 32: to those described for decapod communities 69-95, figs. 1-3. Crawford, D. R., and W. J. J. DeSmidt. 1922. on Floridan worm reefs may occur on The spiny lobster, Panutirus argus, of south- European worm reefs as well. The species ern Florida: its natural history and utiliza- 246 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

tion. Bull. U.S. Bur. Fish. 38 (for 1921-22): figs. ill R. F. Johnston, P. W. Frank, & C. D. 283-310, figs. 260-273. Michener, eds. Annual Review of Ecology & Dejong, T. M. 1975. A comparison of three Systematics, Annual Reviews Inc., Palo Alto, diversity indices based on their components Calif. of richness and evenness. Oikos 26: 222- Hurlbert, S. H. 1971. The nonconcept of spe- 227, figs. 1-5. cies diversity: A critique and alternative Eckelbarger, K. E. 1976. Larval development parameters. Ecology 52: 577-586. and population aspects of the reef-building Kaestner, A. 1970. Invertebrate zoology. Crus- polychaete, Phragmatopoma lapidosa from tacea, Volume III. Interscience Publishers, the east coast of Florida. Bull. Mar. Sci. 26: John Wiley & Sons, New York. xi + 523 pp. 117-132, figs. 1-13. Kirtley, D. W. 1966. Intertidal reefs of Sabel- Fanta, E. S. 1968. Sobre a biologia e ecologia lariidae (Annelida Polychaeta) along the de Phragmatopoma lapidosa (Sabellariidae, coasts of Florida. Unpubl. Master's Thesis, Polychaeta). Ciencia e Cultura, Sao Paulo Florida State University, Tallahassee, Florida, 20: 459-460. vii + 86 pp., 44 figs. Fausto-Filho, 1., and E. Furtado. 1970. Nota 1974. Geological significance of the pre]iminar sobre a fauna das colonies de polychaetous annelid family Sabellariidae. Sabel1ariidae do litoral do Estado do Ceara Unpubl. Dissert., Florida State Univ., ix + (Annelida, Sedentaria). Rev. Brasil. Biol. 270 pp., Appendix A, 142 figs. 30: 285-289, 1 fig. ---, and W. F. Tanner. 1968. Sabellariid Gilmore, R. G. In press. A regional description worms: Builders of a major reef type. J. and checklist of fishes of the Indian River Sediment. Petrol. 38: 73-78, figs. 1-5. lagoon and associated waters, Florida. Bull. Lie, U., and R. A. Evans. 1973. Long-term Fla. St. Mus. variability in the structure of subtidal benthic Gram, R. 1968. A Florida Sabellariidae reef communities in Puget Sound, Washington, and its effect on sediment distribution. J. USA. Mar. BioI. 21: 122-126, 1 fig. Sedm. Petrol. 38: 863-868, figs. 1-3. Lloyd, A. J., and C. M. Yonge. 1947. The biol- Griffin, D. J. G. 1971. The ecological distribu- ogy of Crallgoll vulgaris L. in the Bristol tion of grapsid and ocypodid shore crabs Channel and Severn Estuary. J. Mar. bioI. (Crustacea: Brachyura) in Tasmania. J. Ass. U.K. 26: 626-661. Anim. Ecol. 40: 597-62], figs. 1-5. MacArthur, R. H. 1955. Fluctuations of ani- Gruet, Y. 1970. Faune associee des "recifs" mal populations, and a measure of commu- edifies par l'Annelide Sahellaria alveolala nity stability. Ecology 36: 533-536, figs. (Linne) en baie de Mont Saint-Michel: banc 1-3. des Hermelles. Mem. Soc. Sc. de Cherbourg Margalef, R. 1968. Perspectives in ecological 54 (\969-1970): 1-21, figs. 1-3. theory. Univ. Chicago Press. 111 pp. ---. 1971. Morphologie, croissance et faune Multer, H. G., and 1. D. Milliman. 1967. associee des recifs de Sahellaria alveolala Geologic aspects of sabellarian reefs, south- (Linne) de la Bernerie-En-Retz (Loire At- eastern Florida. Bull. Mar. Sci. 17: 257-267, lantique). Tethys 3: 321-380, figs. 1-13. figs. 1-4. 1972a. Aspects morphologiques et dy- Narchi, W., and S. A. Rodrigues. 1965. Ob- namiques de constructions de I'Annelide servacoes ecol6gicas sobre Phragmalopoma Po]ychete Sahellaria alveolata (Linne). Rev. lapidosa Kinberg. Cicncia e ClIltllra, Sao Trav. Inst. Peches Marit. 36: 131-161, figs. Paulo 17: 228-229. 1-3, pIs. 1-10. Nicol, E. A. T. 1932. Feeding habits of Ga]a- 1972b. Faune associee de "recifs" d' theidea. 1. Mar. bioI. Ass. U.K. 18: 87- Hermelles Po]ychete Sabellariide: Sahellaria 106. alveolata (Linne): cas de recifs morts It Orton, J. H. 1927. On the mode of feeding of Creve-Coeur (La Bernerie, Loire Atlan- the hermit crab Ellpagllrtls bernhardlls and tique). Bu]l. Soc. Scient. Bretagne 47: 69- some other Decapoda. J. Mar. bioI. Ass. 80, figs. 1-5. U.K. 14: 909-921. 1973. Productivite biologique et sta- Paine, R. T. 1966. Food web complexity and bilisation des sediments par les recifs d'Her- species diversity. Amer. Naturalist 100: 65- melles. Bull. Soc. Sciences Nat. Ouest 75. France, 61: 1-10, 4 unnumbered plates. 1969. A note on trophic complexity Heip, C., and P. Engels. 1974. Comparing spe- and community stability. Amer. Naturalist cies diversity and evenness indices. J. Mar. 103: 91-93. Biol. Ass. U.K. 54: 559-563. Peet, R. K. 1975. Relative diversity indices. Holling, C. S. 1973. Resilience and stability of Ecology 56: 496-498. ecological systems. Vol. 4, pages 1-23, 4 Peterson, C. H. 1975. Stability of species and GORE £T AL.: COMMUNITY STABILITY IN WORM REEF CRUSTACEANS 247

of community for the benthos of two la- 15. A. peasei (Armstrong, 1940) goons. Ecology 56: 958-965. 16. A. lllOmasi Hendrix and Gore, 1973 Provenzano, A. J. Jr. 1959. The shallow-water 17. A. viridari (Armstrong, 1949) hermit crabs of Florida. Bull. Mar. Sci. Gulf 18. Metalpheus rostratipes (Pocock, 1890) 19. Synalphells brevicarpus (Herrick, 1891) Caribb. 9: 350-420, figs. 1-21. 20. S. cf. curacaoensis Schmitt, 1924 Rivosecchi, E. T. 1961. Osservazioni sulle bio- 21. S. frilzmuelleri Coutiere, 1909 cenosi del banco a Sabel/aria di Lavinio. 22. S. minus (Say, 1818) Estr. Rend. Accad. Nazionale XL, serie 4, 23. S. townsendi Coutiere, 1909 12: L-ll, 1 fig. 24. Synalphells sp. A Samuelson, T. 1970. The biology of six species of Anomura (Crustacea Decapoda) from H1PPOL YTlDAE Raunefjorden, Western Norway. Sarsia 45: 25. Lysmata intermedia (Kingsley, 1878) 25-52, figs. 1-17. 26. L. wllrdemanni (Gibbes, 1850) Schoener, A. 1974. Experimental zoogeog- raphy: colonization of marine mini-islands. PROCESSIDAE Amer. Naturalist 108: 715-738, figs. 1-4. 27. Processa filllbriata Manning and Chace, 1971 Schoener, T. W. 1974. Resource partitioning in ecological communities. Science 185: 27-39, STENOPODIDAE figs. 1-5. 28. Microproslhema semi/al'vl' (Von Martens, Wilson, D. P.1971. Sabel/aria colonies at 1872) Duckpool, North Cornwall, 1961-1970. J. Mar. bioI. Ass. U.K. 51: 509-580, figs. 1-8, PALINU RIDAE pIs. 1-24. 29. Panulims argus* (Latreille, 1804) DATE ACCEPTED: March 21, 1977. UPOGEBHDAE 30. Upogebia affinis (Say, 1818) ADDRESSES: (R. H. G. and L. E. S.) Smithsonian /I/slill/tiol/, Ft. Pierce BI/reau, Ft. Pierce, Florida PORCELLANIDAE 33450; (L. J. B.) ROllle 2, Box 965, Palalke, 31. Megalobrachillm poeyi (Guerin, 1855) Florida 32007. 32. M. soriatum (Say, 1818) 33. Pachycheles monilifer (Dana, 1852) 34. Petrolistlles armatlls (Gibbes, 1850) 35. P. galatl/inus (Bose, 1801)

DIOGENIDAE APPENDIX 1 36. Calcilllls tibicen (Herbst, 1791) 37. Clibanarills antillensis Stimpson, 1862 DECAPOD AND STOMATOPOD CRUSTA- 38. C. sclopetarius* (Herbst, 1791) CEANS INHABITING, OR ASSOCIATED 39. C. tricolor (Gibbes, 1850) WITH SABELLARIID WORM REEFS IN THE 40. C. vittatus* (Bose, 1802) INDIAN RIVER REGION OF THE CENTRAL 41. Paguristes tortI/gal' Schmitt, 1933 EASTERN FLORIDA COASTLINE 42. Pelrochims diogenes (Linnaeus, 1758)

PENAElDAE PAGURIDAE 1. Melapel/aeopsis goodei* (Smith, 1885) 43. Pagu/'/ls carolinensis McLaughlin, 1975 2. M. smithi~' (Schmitt, 1924) 44. P. pollicaris* Say, 1817 3. Pe//{U'I/s sp. * 4. Sicyonia dorsalis* Kingsley, 1878 ALBUNEIDAE 45. Lepidopa benedicti* Schmitt, 1935 PALAEMONIDAE 5. Neopontonides beallfortensis (Borradaile, H1PPIDAE 1920) 46. Emerila lalpoida* (Say, 1817) 6. Periclilllenes americanus* (Kingsley, 1878) LEUCOSHDAE ALPHEIDAE 47. Uhlias limbatus Stimpson, 1871 7. A/phel/s arlllillatus H. Milne Edwards, 1837 8. A. hOl/vieri* A. Milne Edwards, 1878 9. A. forlllosus Gibbes, 1850 PORTUNIDAE 10. A. heleroc!we/is';' Say, 1818 48. Arenaeus cribrarius* (Lamarck, 1818) 11. A. lIIallealor Dana, 1852 49. Callinectes omatus* Ordway, 1863 12. A. normanni Kingsley, 1878 50. C. similis'~ Williams, 1966 13. A. /I/Ittingi (Schmitt, 1924) 51. Cronius ruber (Lamarck, 1818) 14. A. paracrinilus Miers, 1881 52. Porlunus gibbesii* (Stimpson, 1859) 248 BULLETIN OF MARINE SCIENCE, VOL. 28, NO.2, 1978

XANTHIDAE OCYPODIDAE 53. Platyactaea setigera (H. Milne Edwards, 74. Ocypode quadrata* (Fabricius, 1787) 1834) 54. Cataleptodius floridanus* (Gibbes, 1850) MAJIDAE 55. Eriphia gonagra (Fabricius, 1781) 75. Acanthonyx petivcrii H. Milne Edwards, 1834 56. Eurypanopeus abbreviatus* (Stimpson, 1860) 76. Chorinus heros (Herbst, 1790) 57. E. depressus* (Smith, 1869) 77. Epialtus bituberculatus H. Milne Edwards, 58. E. dissimilis* (Benedict and Rathbun, 1891) 1834 78. E. dilatatus A. Milne Edwards, 1878 59. Hexapanopeus angustifrons (Benedict and 79. Macrocoeloma subparallelum (Stimpson, Rathbun, 1891) 1860) 60. H. paulensis Rathbun, 1930 80. Microphrys bicomutus (Latreille, 1825) 61. Menippe mercenaria (Say, 1818) 81. M. antillensis Rathbun, 1920 62. M. nodifrons Stimpson, 1859 82. Mithrax aCllticomis Stimpson, 1870 63. Micropanope granulimanus (Stimpson, 1871) 83. M. coryphe (Herbst, 1785) 64. Panopeus bermudensis Benedict and Rathbun, 84. M. forceps (A. Milne Edwards, 1875) 1891 85. M. hispidlls (Herbst, 1790) 65. P. herbstii* H. Milne Edwards, 1834 86. M. pleuracanthus Stimpson, 1871 66. P. occidellta/is* Saussure, 1857 87. M. ruber (Stimpson, 1871) 67. Pilumnus dasypodus Kingsley, 1879 88. M. verrucosus* H. Milne Edwards, 1832 68. P. lacteus Stimpson, 1871 89. Pelia mutica (Gibbes, 1850) 69. P. sayi Rathbun, 1897 90. Pitho lherminieri (Schramm, 1867) 70. XantllO denticulatus (White, 1847) 91. Podochela riisei Stimpson, 1860 92. P. sidneyi Rathbun, 1924 93. Stenorhynchus seticornis (Herbst, 1788) GRAPSIDAE 71. Pachygrapsus transversus (Gibbes, 1850) GONODACTYLIDAE 72. Plagusia depressa (Fabricius, 1775) 94. GOllodactyllls bredini Manning, 1969 95. G. oerstedii Hansen, 1895 96. G. spil1uloslls Schmitt, 1924 GECARCINIDAE • Associated with but not actually living on or within the 73. Gecarcinus latera/is* (Fremin ville, 1835) reef itself.