Using ecological science for potentially expensive short-term interventions for substantial long-term environmental, cultural and economic gain in coastal regionsMacroalgae and Ecosystem Services (sponsored by Annals of Botany)

David Schiel¹, Shane Orchard¹, Rahera Ohia², Christopher Battershill²

¹University of Canterbury, New Zealand - ²University of Waikato, New Zealand

Descriptions abound in the literature of degraded coastal ecosystems from a wide range of stressors and what we “must do” to reverse such degradation. However, not all stressors are manageable, and they operate at various spatial and temporal scales. These include the usual litany of heat waves, warming seas, sea-level rise, contaminants and overfishing but also, increasingly cross-ecosystem effects from urbanisation, intensified land use and coastal runoff through waterways, especially of fine sediments. In many, if not most, cases restoration of key species or ecosystems is not feasible at relevant scales unless the underlying problems that caused degradation are ameliorated. If ecological science is to solve these pernicious problems with practical solutions rather than theoretical ones, it must be at the forefront of working with managers and communities who can effect meaningful change. Here we describe a research program examining catastrophic degradation of coastal kelp communities and scallop beds. The common cluster of stressors affecting these systems are cross-ecosystem flows of sediments exacerbated by major storm events and co-occurring marine heat waves. Consequent losses are to fisheries, biogenic habitat and, importantly, associated societal and cultural values precious to New Zealanders. Restoration and preservation of habitat, and ‘turning off the taps’ of sediment flows are key features, which have substantial short-term and long-term financial costs that need to be borne in the face of many competing needs. As espoused by our indigenous Māori partners, none of this is possible without an inter-generational view of coastal ecosystems.