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Oecologia

, Volume 137, Issue 1, pp 97–103 | Cite as

Negative effects overpower the positive of kelp to exclude invertebrates from the understorey community

  • Sean D. ConnellEmail author
Community Ecology

Abstract

Marine macroalgal forests are one of the most widespread and studied habitats on subtidal coasts, but there remain challenges in understanding why many sessile invertebrates are anomalously absent from understorey communities. In a series of experiments on recruitment of invertebrates, I partitioned the habitat-modifying effects of kelp into their positive and negative effects. Experiments revealed that a reduction of light intensity and removal of sediment by canopies acted to facilitate recruitment, but physical abrasion by the canopy acted as a negative force to overpower these positive effects. Understorey assemblages, therefore, represent biased subsets of taxa from a local pool capable of colonization. On balance, negative effects acted to exclude invertebrates from the understorey community. The asymmetric strength of negative effects not only explains the enigma of exclusion but also indicates that, when it exists, understorey coexistence with canopy plants must reflect a more even match between positive and negative effects.

Keywords

Canopy Disturbance Facilitation Sedimentation Subtidal 

Notes

Acknowledgements

This manuscript was improved by the comments of Bronwyn Gillanders, Tim Glasby, Jason Tanner and two anonymous referees. Many hours of capable diving assistance were provided by B. Gillanders, M. Fowler-Walker, A. Irving and A. Melville. This research was financed by an Australian Research Council grant.

References

  1. Aide TM (1987) Limbfalls: a major cause of sapling mortality for tropical forest plants. Biotropica 19:284–285Google Scholar
  2. Airoldi L, Virgilio M (1998) Responses of turf-forming algae to spatial variations in the deposition of sediments. Marine Ecology Progress Series 165:271–282Google Scholar
  3. Bertness MD, Leonard GH, Levine J, Schmidt P, Ingraham A (1999) Testing the relative contribution of positive and negative interactions in rocky intertidal communities. Ecology 80:2711–2726Google Scholar
  4. Bruno J, Stachowicz J, Bertness MD (2003) Inclusion of facilitation into ecological theory. Trends Ecol Evol (in press)Google Scholar
  5. Callaway RM, et al (2002) Positive interactions among alpine plants increase with stress. Nature 417:844–848CrossRefPubMedGoogle Scholar
  6. Clark DB, Clark DA (1989) The role of physical damage in the seedling mortality regime of a neotropical rain forest. Oikos 55:225–230Google Scholar
  7. Connell JH, Keough MJ (1985) Disturbance and patch dynamics of subtidal marine animals on hard substrata. In: Pickett STA, White PS (eds) The ecology of natural disturbance and patch dynamics. Academic Press, New York, pp 101–124Google Scholar
  8. Connell SD (2003) The monopolization of understorey habitat by subtidal encrusting coralline algae: a test of the combined effects of canopy-mediated light and sedimentation. Mar Biol 142:1065–1071Google Scholar
  9. Connell SD, Glasby TM (1999) Do urban structures influence local abundance and diversity of subtidal epibiota? A case study from Sydney Harbour. Mar Environ Res 47:373–387CrossRefGoogle Scholar
  10. Dayton PK (1971) Competition, predation, and community organisation: the provision and subsequent utilization of space in a rocky intertidal community. Ecol Monogr 41:351–389Google Scholar
  11. Dayton PK (1975) Experimental studies of algal canopy interactions in a sea otter-dominated kelp community at Amchitika Island, Alaska. Fish Bull 73:230–237Google Scholar
  12. Eckman JE (1983) Hydrodynamic processes affecting epibenthic recruitment. Limnol Oceanogr 28:241–257Google Scholar
  13. Fowler-Walker MJ, Connell SD (2002) Opposing states of subtidal habitat across temperate Australia: consistency and predictability in kelp canopy—understorey associations. Mar Ecol Prog Ser 240:49–56Google Scholar
  14. Glasby TM (1999) Effects of shading on subtidal epibiotic assemblages. J Exp Mar Biol Ecol 234:275–290CrossRefGoogle Scholar
  15. Irving AD, Connell SD (2002a) Sedimentation and light penetration interact to maintain heterogeneity of subtidal habitats: algal vs invertebrate dominated assemblages. Mar Ecol Prog Ser 245:83–91Google Scholar
  16. Irving AD, Connell SD (2002b) Interactive effects of sedimentation and microtopography on the abundance of subtidal turfing algae. Phycologia 41:517–522Google Scholar
  17. James PL, Larkum AWD (1996) Photosynthetic inorganic carbon acquisition of Posidonia australis. Aquat Bot 55:149–157CrossRefGoogle Scholar
  18. Keddy P (1992) Assembly and response rules: two goals for predictive community ecology. J Veg Sci 3:157–164Google Scholar
  19. Kendrick GA (1991) Recruitment of coralline crusts and filamentous turf algae in the Galapagos archipelago: effect of sediment scour, erosion and accretion. J Exp Mar Biol Ecol 147:47–63Google Scholar
  20. Kennelly SJ (1989) Effects of kelp canopies on understorey species due to shade and scour. J Exp Mar Biol Ecol 168:35–58Google Scholar
  21. Kennelly SJ (1991) Caging experiments to examine the effects of fishes on understorey species in a sublittoral kelp community. J Exp Mar Biol Ecol 147:207–230Google Scholar
  22. Meese RJ, Tomich PA (1992) Dots on the rocks: a comparison of percent cover estimation methods. J Exp Mar Biol Ecol 165:59–73Google Scholar
  23. Melville AJ, Connell SD (2001) Experimental effects of kelp canopies on subtidal coralline algae. Aust Ecol 26:102–108CrossRefGoogle Scholar
  24. Sebens KP (1986) Spatial relationships among encrusting marine organisms in the New England subtidal zone. Ecol Monogr 56:73–96Google Scholar
  25. Shepherd SA, Womersley HBS (1970) The sublittoral ecology of West Island, South Australia. 1. Environmental features and algal ecology. Trans R Soc South Aust 94:105–137Google Scholar
  26. Steneck RS (1986) The ecology of coralline algal crusts: convergent patterns and adaptive strategies. Annu Rev Ecol Syst 17:273–303Google Scholar
  27. Thorson G (1964) Light as an ecological factor in the dispersal and settlement of larvae of marine bottom invertebrates. Ophelia 1:167–208Google Scholar
  28. Underwood AJ (1997) Experiments in ecology. Their logical design and interpretation using analysis of variance. Cambridge University Press, CambridgeGoogle Scholar
  29. Velimirov B, Griffiths CL (1979) Wave-induced kelp movement and its importance for community structure. Bot Mar 22:169–172Google Scholar
  30. Witman JD, Dayton PK (2001) Rocky subtidal communities. In: Bertness MD, Gaines SD, Hay ME (eds) Marine community ecology. Sinauer Associates, Sunderland, pp 339–366Google Scholar
  31. Wootton JT (2001) Local interactions predict large-scale pattern in empirically derived cellular automata. Nature 413:841–844CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Southern Seas Ecology Laboratories, School of Earth and Environmental SciencesThe University of AdelaideAustralia

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