When rhodoliths do not roll: Invertebrate community responses to environmental stability and natural disturbance
Authors: Hinojosa-Arango, G., Maggs, C.A., Johnson, M.P. and Riosmena-Rodríguez, R.
Pages: 131-151
Abstract:Rhodolith beds are aggregations of free-living, non-geniculated coralline algae with a worldwide occurrence. Their distribution and survivorship is regulated by many factors, from which light, temperature, and sedimentation are considered as main restrainers of growth and structure. Rhodoliths are bioengineers and provide a three-dimensional habitat for associated species. Distinctive faunal and floral assemblages of high diversity are harbored by rhodolith thalli by virtue of their branching and interlocking nature. Rhodolith communities are of ecological and economical importance around the world and subject to periodical events disturbance. Periodic rotation is necessary, but does not need to be frequent, to prevent sedimentation and to allow light reaching all surfaces of the thalli. This rotation is a natural disturbance, stochastic phenomena recognized as an important determinant of presence and abundance of associated species. After a disturbance event the associated community with any substratum starts a recovery process that might eventually return it to what it used to be. This process can take from days up to years. In this chapter, the role of disturbance in structuring the invertebrate assemblages associated with two rhodolith beds was studied. We artificially stabilized rhodolith thalli for periods of 6 months to analyze the response of the associated invertebrate community to stability and disturbance. Samples from untied thalli (natural) were compared to artificially stabilized rhodoliths. Results demonstrated that the influence of disturbance on invertebrate assemblages is not simple and will strongly depend on the characteristics of the disturbance as well as the physiological, morphological and behavioral capabilities of the species present at any given time. Factors such as the time of the year when disturbance events happen can modify the recovery patterns of the assemblage diversity. The patterns of the species associated with natural and artificially stabilized rhodoliths emerge at three scales: a) between stability periods (two, four and six months), b) between levels of stability (natural and stabilized thalli), and c) among assemblages in experiments started on different dates. The value of rhodoliths as a unique biotope is under threat by different kinds of human activities around the world. The lack of regulation on small and large scale trawling, reduction of water quality, modification of water circulation, ocean acidification, and any other activities that affect rhodolith stability and disturbance are of special concern. Invertebrate assemblages on rhodolith beds provide recruits for many commercial fisheries around the world. It is necessary to take into consideration the response of these assemblages to both natural and artificial disturbance in the development and implementation of coastal management plans around the world. © 2013 by Nova Science Publishers, Inc. All rights reserved.
Source: Scopus