Too close for comfort: spatial patterns in acorn barnacle populations

Hooper, Rebecca C.; Eichhorn, Markus P.

Abstract

Spatial patterns in aggregations form as a result of the interplay between costs and benefits experienced by individuals. Such self-organisation of aggregations can be explained using a zonal model in which a short-range zone of repulsion and longer-range zone of attraction surrounding individuals leads to emergent pattern properties. The signal of these processes can be detected using spatial pattern analyses. Furthermore, in sessile organisms, post-settlement mortality reveals the relative costs and benefits of positions within the aggregation. Acorn barnacles are known to require contact with conspecifics for reproduction and are therefore believed to aggregate for this purpose; isolated individuals may also be more susceptible to abiotic stress and predation. At short distances, however, competition for space and resources is likely to occur. In this study spatial patterns of barnacles (Semibalanus balanoides L.) were analysed using pair-correlation functions. Individuals were dispersed at distances below 0.30 cm, but peak relative density occurred at a distance of 0.36 cm from conspecifics. This is much closer than required for reproductive access, implying a strong aggregative drive, up to the point of physical contact with neighbours. Nevertheless, analysis of dead barnacles illustrated that such proximity carries a cost as barnacles with many neighbours were more likely to have died. The inferences obtained from these patterns are that barnacles aggregate as closely as they can, and that local neighbourhood competition is a powerful determinant of mortality. These processes give rise to the observed pattern properties.

Citation

Hooper, R. C., & Eichhorn, M. P. (2016). Too close for comfort: spatial patterns in acorn barnacle populations. Population Ecology, 58(2), 231-239. https://doi.org/10.1007/s10144-016-0542-5

• Journal Article Type: Article
• Acceptance Date: Feb 15, 2016
• Online Publication Date: Mar 3, 2016
• Publication Date: Apr 1, 2016
• Deposit Date: Mar 18, 2016
• Publicly Available Date: Mar 18, 2016
• Journal: Population Ecology
• Print ISSN: 1438-3896
• Electronic ISSN: 1438-3896
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 58
• Issue: 2
• Pages: 231-239
• DOI: https://doi.org/10.1007/s10144-016-0542-5
• Keywords: Intertidal ; Pair correlation function ; Self-organisation ; Semibalanus balanoides ; Spatial point patterns ; Zone of interaction
• Public URL: https://nottingham-repository.worktribe.com/output/777758
• Publisher URL: http://link.springer.com/article/10.1007/s10144-016-0542-5/fulltext.html
• Additional Information: The final publication is available at Springer via http://dx.doi.org/10.1007/s10144-016-0542-5