strips of coastal vegetation lacking fully functionality. Current land-use change
adversely affects quality and quantity of coastal habitats through pollution, reduced
sediment availability, suppressed natural dynamics, among others. These may ultimately result in just small and rather isolated strips of still well-functioning habitats.
These negative changes are connected to a strong intensification of industry and a
rapidly increasing building development (settlements, tourism, coastal defence).
Moreover, regional and global shifts in climatic conditions and relative sea-level
rise, although difficult to predict, may strengthen the effects of other human impacts.
Consequently, the natural dynamic and the capacity of coastal habitats to migrate
inland and to build up vertically is reduced. At regional level, serious damages have
been recorded already for coastal habitats in shallow waters. Regarding small
islands, atolls and other vulnerable places, solutions are required. Thus, we are in
urgent need to think about and act with long-term, resilient and cost-efficient
protection measures.
Conventional coastal engineering is getting increasingly costly due to the need of
adjusting the rigid constructions to prevent the growing risk of flooding. It additionally facilitates land subsidence and adversely effects sediment availability owed to
the disruption of natural coastal dynamics (Temmerman et al. 2013). Sediment
availability is further reduced by sediment compaction from the removal of oil,
gas, salt and water from underlying sediments (Syvitski et al. 2009). We therefore
need to focus on and implement nature-based solutions. Already now, wellfunctioning coastal habitats, such as mangroves, saltmarshes, seagrass beds and
coral reefs, contribute to the protection of our coastlines across all biogeographical
regions of the world. And so, their capacity to attenuate flood waves and storm
surges, to decrease erosion, to accumulate sediments (e.g. Spalding et al. 2014) and
thus, their capability to grow vertically in relation to sea-level rise (Kirwan and
Megonigal 2013) makes them a serious alternative or addition to artificial coastal
defence. Studies investigating the capacity of intertidal habitats to function as coastal
protection show promising concepts and encouraging results. Still, we need to
understand more about the response of coastal habitats to sea-level rise and increasingly unpredictable flooding events on regional as well as on global scales. For
example, judging the extent of coastal habitats attenuating storm surges differs
between studies (Fonseca and Cahalan 1992; Mcivor et al. 2012; Möller et al.
1999), because of its dependence on frictional effects, wind speed and duration
(Resio and Westerink 2008). Restrictions in coastal protection are given in relation
to large-scale erosion and enormous tsunami waves (Gedan et al. 2011).
To enable nature-based coastal protection, the conservation and restoration of
coastal habitats aiming to build a natural, interconnected and fully functional coastal
landscape is required. The functionality of coastal habitats relies on an unhindered
spatial and temporal dynamic, which includes horizontal movements, suitable sediment availability (enabling vertical accretion) and a complete species pool. For
example, the functional breakdown of coastal habitats owing to sea-level rise may be
related to the constraints in horizontal migration of habitats and its successional
stages (called coastal squeeze; Feagin et al. 2005), due to the natural geomorphology
of the landscape or by socio-economic barriers. Reducing these barriers where
Coastal Habitats, Shallow Seas and Inland Saline Steppes: Ecology,. . .
303
adversely affects quality and quantity of coastal habitats through pollution, reduced
sediment availability, suppressed natural dynamics, among others. These may ultimately result in just small and rather isolated strips of still well-functioning habitats.
These negative changes are connected to a strong intensification of industry and a
rapidly increasing building development (settlements, tourism, coastal defence).
Moreover, regional and global shifts in climatic conditions and relative sea-level
rise, although difficult to predict, may strengthen the effects of other human impacts.
Consequently, the natural dynamic and the capacity of coastal habitats to migrate
inland and to build up vertically is reduced. At regional level, serious damages have
been recorded already for coastal habitats in shallow waters. Regarding small
islands, atolls and other vulnerable places, solutions are required. Thus, we are in
urgent need to think about and act with long-term, resilient and cost-efficient
protection measures.
Conventional coastal engineering is getting increasingly costly due to the need of
adjusting the rigid constructions to prevent the growing risk of flooding. It additionally facilitates land subsidence and adversely effects sediment availability owed to
the disruption of natural coastal dynamics (Temmerman et al. 2013). Sediment
availability is further reduced by sediment compaction from the removal of oil,
gas, salt and water from underlying sediments (Syvitski et al. 2009). We therefore
need to focus on and implement nature-based solutions. Already now, wellfunctioning coastal habitats, such as mangroves, saltmarshes, seagrass beds and
coral reefs, contribute to the protection of our coastlines across all biogeographical
regions of the world. And so, their capacity to attenuate flood waves and storm
surges, to decrease erosion, to accumulate sediments (e.g. Spalding et al. 2014) and
thus, their capability to grow vertically in relation to sea-level rise (Kirwan and
Megonigal 2013) makes them a serious alternative or addition to artificial coastal
defence. Studies investigating the capacity of intertidal habitats to function as coastal
protection show promising concepts and encouraging results. Still, we need to
understand more about the response of coastal habitats to sea-level rise and increasingly unpredictable flooding events on regional as well as on global scales. For
example, judging the extent of coastal habitats attenuating storm surges differs
between studies (Fonseca and Cahalan 1992; Mcivor et al. 2012; Möller et al.
1999), because of its dependence on frictional effects, wind speed and duration
(Resio and Westerink 2008). Restrictions in coastal protection are given in relation
to large-scale erosion and enormous tsunami waves (Gedan et al. 2011).
To enable nature-based coastal protection, the conservation and restoration of
coastal habitats aiming to build a natural, interconnected and fully functional coastal
landscape is required. The functionality of coastal habitats relies on an unhindered
spatial and temporal dynamic, which includes horizontal movements, suitable sediment availability (enabling vertical accretion) and a complete species pool. For
example, the functional breakdown of coastal habitats owing to sea-level rise may be
related to the constraints in horizontal migration of habitats and its successional
stages (called coastal squeeze; Feagin et al. 2005), due to the natural geomorphology
of the landscape or by socio-economic barriers. Reducing these barriers where
Coastal Habitats, Shallow Seas and Inland Saline Steppes: Ecology,. . .
303