Summary
Guilds of crustose bryozoans exhibited a range of growth outlines, varying from circular to elongate, and the stones on which they grew contained a range of refuge types, varying in size from a few mm2 to a few hundred cm2. These refuges, if encountered by the growing colonies of competitively subordinate species such as Electra pilosa L., enabled the latter to avoid competitive exclusion due to overgrowth mortality. Computer simulations suggested that, although modular organisms which are elongate are, in general, more likely to encounter spatial refuges than those with a different shape through vegetative growth, shape is less important than the size of the organisms themselves or the size and density of the spatial refuges. Moreover significant interactions between these 4 variables showed that they should be considered together and not in isolation from one another. Examples are given of variable growth forms in continuous, modular organisms from different taxa, including plants, and the importance of these predictive studies to refuge location by modular organisms is discussed.
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References
Ayling AM (1983) Factors affecting the spatial distribution of thinly encrusting sponges from temperate waters. Oecologia (Berlin) 60:412–418
Buss LW (1979) Habitat selection, directional growth and spatial refuges: why colonial animals have more hiding places. In: Larwood GP, Rosen BR (eds) Biology and systematics of colonial organisms. Systematics Association Special vol 11, Academic Press, New York, pp 459–497
Buss LW (1981) Mechanisms of competition between Onychocella alula (Hastings) and Antropora tincta (Hastings) on an eastern Pacific rocky shoreline. In: Larwood GP, Nielsen C (eds) Recent and fossil Bryozoa, Olsen and Olsen, Fredensborg, pp 39–50
Buss LW, McFadden CS, Keene DR (1984) Biology of hydractiniid hydroids. 2. Histocompatibility of effector system/competitive mechanism mediated by nematocyst discharge. Biol Bull 167:139–158
Buss LW, Moore JL, Greene DR (1985) Autoreactivity and selftolerance in an invertebrate. Nature (London) 313:400–402
Clarke GM (1980) Statistics and experimental design. Edward Arnold, London
Grime JP (1979) Plant strategies and vegetation processes. John Wiley, Chichester.
Håkansson E, Thomsen E (1985) Clonal propagation in fossil cheilostomes. In: Nielsen C, Larwood GP (eds) Bryozoa: Ordovician to recent. Olsen and Olsen, Fredensborg, p 345
Harmelin J-G (1977) Bryozoaires des îles d'Hyères: cryptofaune bryozoologique des valves vides de Pinna nobilis rencontrées dans les herbiers de Posidonies. Trav Sci Parc Natl Port-Clos 3:89–120
Harper JL (1981) The concept of population in modular organisms. In: May RM (ed) Theoretical ecology, Blackwell Scientific Publications, Oxford, pp 53–77
Hondt J-L d' (1984) Bryozoaires épibiontes sur le brachiopod articulé Gryphus vitreus (Born 1778) en mer Méditerranée occidentale (Corse). Vie et Milieu 34:27–33
Jackson JBC (1977) Competition on marine hard substrata: the significance of solitary and colonial strategies. Am Nat 111:743–767
Jackson JBC (1979a) Morphological strategies of sessile animals. In: Larwood GP, Rosen BR (eds) Biology and systematics of colonial organisms. Systematics Association Special vol 11, Academic Press, New York, pp 499–555
Jackson JBC (1979b) Overgrowth competition between encrusting cheilostome ectoprocts in a Jamaican cryptic reef environment. J Anim Ecol 48:805–823
Jong TJ de, Klinkhamer PGL (1985) The negative effects of litter of parent plants of Cirsium vulgare on their offspring: autotoxicity or immobilization? Oecologia (Berlin) 65:153–160
Kay AM, Keough MJ (1981) Occupation of patches in the epifaunal communities on pier pilings and the bivalve Pinna bicolor at Edithburgh, South Australia. Oecologia (Berlin) 48:123–130
Keough MJ (1984) Effects of patch size on the abundance of sessile marine invertebrates. Ecology 65:423–437
King TJ (1977a) The plant ecology of ant-hills in calcareous grasslands. I. Patterns of species in relation to ant-hills in southern England. J Ecol 65:235–256
King TJ (1977b) The plant ecology of ant-hills in calcareous grasslands. II. Succession on the mounds. J Ecol 65:257–278
Liddell WD, Brett CE (1982) Skeletal overgrowth among epizoans from the Silurian (Wenlockian) Waldron Shale. Paleobiology 8:67–78
López Gappa JJ (1981) Sobre la presencia de Chorizopora brongniartii (Audouin, 1826) (Bryozoa, Cheilostomata) en la costa atlántica de America del Sur. Physis (Buenos Aires), Secc A 98:43–45
McFadden CS, McFarland MJ, Buss LW (1984) Biology of hydractiniid hydroids. 1. Colony ontogeny in Hydractinia echinata (Fleming). Biol Bull 166:54–67
Rubin JA (1982) The degree of intransitivity and its measurement in an assemblage of encrusting cheilostome Bryozoa. J Exp Mar Biol Ecol 60:119–128
Rubin JA (1985) Mortality and avoidance of competitive overgrowth in encrusting Bryozoa. Mar Ecol Prog Ser 23:291–299
Ryan TA, Joiner BL, Ryan BF (1976) MINITAB student handbook. Duxbury Press, North Scituate
Ryland JS, Stebbing ARD (1971) Settlement and orientated growth in epiphytic and epizoic bryozoans. In: Crisp DJ (ed) Proc 4th Europ Mar Biol Symp. Cambridge University Press, Cambridge, pp 105–123
Schaaf A (1974) Les modalités de la croissance chez quelques bryozoaires cheilostomes. Application a l'espèce Steginooporella rhodanica Buge et David, 1967. Trav Lab Géol Univ Lyon 60:1–82
Sebens KP (1982) Competition for space: growth rate, reproductive output and escape in size. Am Nat 120:189–197
Silén L (1982) Multizooidal budding in Parasmittina trispinosa (Johnston) (Bryozoa, Cheilostomata). Acta Zool (Stockholm) 63:25–32
Sokal RR, Rohlf FJ (1982) Biometry. Freeman, San Francisco
Winston JE (1976) Experimental culture of the estuarine ectoproct Conopeum tenuissimum from Chesapeake Bay. Biol Bull 150:318–335
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Rubin, J.A. Growth and refuge location in continuous, modular organisms: experimental and computer simulation studies. Oecologia 72, 46–51 (1987). https://doi.org/10.1007/BF00385043
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DOI: https://doi.org/10.1007/BF00385043