Intertidal Flats: Ecosystem Functioning of Soft Sediment Systems

he terminology of ecology has been steadily evolving over the years since Eugenius Warming arguably first established the discipline in 1895 (Goodland, 1975). Early ecological work was largely descriptive of species and habitats, often concerned with changes in plant communities over time. This work formed the classical study of the successional progression of assemblages toward a putative vegetative climax. Therefore, ecological concepts and terms suitable for the scales and temporal variation of terrestrial habitats were initially developed. The abiotic component of the habitat was considered to provide the overarching framework within which species might compete and be successful, leading to Clement’s original monoclimax theory of successional change (Townsend et al., 2008). The physical environment was therefore the stage upon which the biotic actors played their roles. This paradigm is now largely rejected as too simplistic since it is now widely recognized that the organisms inhabiting an ecosystem have a range ofeffects on the physical structure and dynamics of the system and contribute as architects of their own habitat (Hansell, 2005). This is particularly true of aquatic depositional systems where organisms burrow, restructure, and process the material of their surroundings in a process known as bioturbation (Reise, 2002). However, ecological paradigms are still generally being developed for terrestrial habitats, and there is a clear lag in the application of these theories to aquatic systems (Raffaelli et al., 2005). However, there is a new urgency in addressing coastal ecology (Duarte et al., 2008), which is being driven by the challenge of managing marine systems under scenarios of global climate change. One of the strongest intellectual drivers is to understand the processes that occur in an ecosystem that are beneficial, or even essential, to humans. These beneficial processes or functions have been described as ecosystem services (Chapin et al., 1997), and understanding them requires knowledge of how the biota provide to these critical services. The biotic component of the system is often reported as some measure of the variety of species that contribute to the process, under the general term of “biodiversity” (Magurran, 2004). Thus the question becomes “How does biodiversity affect ecosystem function?”