Defined broadly as the place where the land meets the sea, the coast occupies a profound place of importance in society (UNEP, 2006; Martinez et al., 2007). Because of both sea- and land-derived inputs, coastal ecosystems are centers of high biological productivity, and they provide us with an astounding array of goods and services, including commercial products, dietary protein, fisheries nursery grounds, water filtration, and climate regulation (Burke et al., 2001; Barbier et al., 2011). The coastal landscape has consistently been a preferred location for human settlement, and its attractiveness as such has increased substantially over the past several decades (Small & Nichols, 2003; Coverdale et al., 2013), particularly as a recreational destination and outlet for emotional uplift (Granek et al., 2010). Coastal ecosystems also have immense cultural importance that can transcend socioeconomic groups (UNEP, 2006; Duke et al., 2013). From the chic surf cultures in California and Costa Rica to the subsistence fishing villages in southeast Asia, religious, recreational, and economic cultures are deeply rooted in coastal habitats. Despite this importance, and likely because of it, coastal ecosystems are subject to multiple stressors that have combined to degrade the services they provide across most of their worldwide areal extent (Halpern et al., 2008). Common threats across habitats include overexploitation, pollution, invasive species, and the impacts of climate change.
In this book, we focus on characterizing the biodiversity of coastal ecosystems, and the conservation of these species in the face of multiple, often synergistic, environmental impacts. Coastal biodiversity has largely been overlooked within coastal management frameworks and has proven difficult to adequately account for in systematic conservation planning schemes, leaving its protection in doubt (Stoms et al., 2008; Tallis et al., 2008; Beger et al., 2010). Yet, biodiversity plays a significant role in both the direct and indirect services provided by coastal ecosystems. In this opening chapter, we provide an overview of coastal biodiversity, highlighting its importance in ecosystem function and the complexities in its measurement and management.