response of the beach to storm events, increasing the rate of erosion of the
shoreline and destroying archeological sites near the coast (Pilkey et al. 2007).
Other small-scale and routine activities can dramatically affect these ecosystems:
For example, beach cleaning (Poinar 1977; Llewellyn and Shackley 1996;
Engelhard and Withers 1997; Dugan et al. 2003; Davenport and Davenport 2006),
which, in addition to removing waste, also eliminates propagules and nutrients,
disturbs organisms that inhabit the beach and flattens or changes the texture of the
sand, exposing more of the surface to the erosive effect of wind. When such
cleaning is conducted with machinery, the damage is intensified because of the
associated physical compaction of the sand.
19.3.5 Factors Favoring Restoration and Criteria that Permit
Prioritization of Restoration Requirements
Facilitators, i.e., those elements that facilitate restoration actions, constituted the
criterion most highly valued by the experts. This criterion comprises two subcriteria:
biotic and abiotic elements. Of these, the subcriterion ‘‘abiotic elements’’ was given
the highest weighting. This reflects the fact that, when restoration activities are
performed under adverse geomorphological conditions, they have little chance of
success (Anfuso et al. 2000; Gallego-Fernández et al. 2003). For example, eroded
beaches usually feature breakwaters, which, while contributing to the accumulation
of sediment at their immediate location, create an imbalance in the processes of
erosion accumulation and material transport, leading to modification of the coastline
(Moreno-Casasola et al. 2006). Furthermore, experience worldwide has shown that
the construction of fixed structures is both expensive and counterproductive in terms
of erosion prevention, while beach nourishment can have adverse effects on the biota
(Finkl and Walker 2004; Nelson 1993a, b; Bishop et al. 2006; Peterson et al. 2006;
Speybroeck et al. 2006). On the other hand, the subcriterion ‘‘biotic elements’’
received a lower weighting. This may be because, although considered valuable
elements for the system, several methods exist for the reintroduction of pioneer
species from nearby fragments as well as for cultivating these plants under greenhouse conditions (e.g., Ley-Vega et al. 2007) and these methods have already proved
to be relatively successful. It is also important to remember that, within these
environments, abiotic elements dominate the system: if they do not function properly, then the biotic elements are strongly affected.
The criteria relating to elements that assist the prioritization of beach and dune
restoration received the lowest weighting. This may be due to the difficulty of
measuring the indicators considered here. For example, the presence of endangered species and the frequency of floods are indicators that are extremely
sensitive to a lack of reliable information. Some of the indicators presented here
have been previously used to assess the vulnerability of coastal dunes and beaches
in Spain, Portugal, the UK, Chile, and the Gulf of Mexico (Williams et al. 1993,
1994, 2001; Pereira et al. 2000; García-Mora et al. 2001; Martínez et al. 2006;
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D. Lithgow et al.
shoreline and destroying archeological sites near the coast (Pilkey et al. 2007).
Other small-scale and routine activities can dramatically affect these ecosystems:
For example, beach cleaning (Poinar 1977; Llewellyn and Shackley 1996;
Engelhard and Withers 1997; Dugan et al. 2003; Davenport and Davenport 2006),
which, in addition to removing waste, also eliminates propagules and nutrients,
disturbs organisms that inhabit the beach and flattens or changes the texture of the
sand, exposing more of the surface to the erosive effect of wind. When such
cleaning is conducted with machinery, the damage is intensified because of the
associated physical compaction of the sand.
19.3.5 Factors Favoring Restoration and Criteria that Permit
Prioritization of Restoration Requirements
Facilitators, i.e., those elements that facilitate restoration actions, constituted the
criterion most highly valued by the experts. This criterion comprises two subcriteria:
biotic and abiotic elements. Of these, the subcriterion ‘‘abiotic elements’’ was given
the highest weighting. This reflects the fact that, when restoration activities are
performed under adverse geomorphological conditions, they have little chance of
success (Anfuso et al. 2000; Gallego-Fernández et al. 2003). For example, eroded
beaches usually feature breakwaters, which, while contributing to the accumulation
of sediment at their immediate location, create an imbalance in the processes of
erosion accumulation and material transport, leading to modification of the coastline
(Moreno-Casasola et al. 2006). Furthermore, experience worldwide has shown that
the construction of fixed structures is both expensive and counterproductive in terms
of erosion prevention, while beach nourishment can have adverse effects on the biota
(Finkl and Walker 2004; Nelson 1993a, b; Bishop et al. 2006; Peterson et al. 2006;
Speybroeck et al. 2006). On the other hand, the subcriterion ‘‘biotic elements’’
received a lower weighting. This may be because, although considered valuable
elements for the system, several methods exist for the reintroduction of pioneer
species from nearby fragments as well as for cultivating these plants under greenhouse conditions (e.g., Ley-Vega et al. 2007) and these methods have already proved
to be relatively successful. It is also important to remember that, within these
environments, abiotic elements dominate the system: if they do not function properly, then the biotic elements are strongly affected.
The criteria relating to elements that assist the prioritization of beach and dune
restoration received the lowest weighting. This may be due to the difficulty of
measuring the indicators considered here. For example, the presence of endangered species and the frequency of floods are indicators that are extremely
sensitive to a lack of reliable information. Some of the indicators presented here
have been previously used to assess the vulnerability of coastal dunes and beaches
in Spain, Portugal, the UK, Chile, and the Gulf of Mexico (Williams et al. 1993,
1994, 2001; Pereira et al. 2000; García-Mora et al. 2001; Martínez et al. 2006;
316
D. Lithgow et al.