P. rustica and P. ferruginea in the lower horizon of the midlittoral, many species of
trochids and the false limpet Siphonaria pectinata, a pulmonate mollusc convergent
in shape with the true limpets; the polyplacophoran Lepidochitona caprearum is also
frequent. The mussels (Mytilus galloprovincialis and Perna perna) form mixed
aggregations where wave action is sufficient, and the sea anemone Actinia equina
is also a conspicuous element in shaded areas of exposed sites. At the lower levels
among the algal turf, the fauna is very diverse, and there are many other small
species of different groups. Molluscs are quite thoroughly studied (Gofas et al.
2011), and the most characteristic species in the midlittoral algal turf are Skeneopsis
planorbis, Nodulus spiralis, Pisinna glabrata, Tricolia miniata, and Cassiella
abylensis, the latter an endemic species of the Strait of Gibraltar. Other groups
(pycnogonids, amphipods, copepods, isopods, polychaetes, tanaids, insect larvae,
ostracods, mites, nematodes, ophiuroids, echinoids, sponges, bryozoans and foraminifera) are also diverse but not studied in detail yet. A study about gammarid
amphipods inhabiting intertidal seaweed of Tarifa found a distinct vertical segregation of the species (Krapp-Schickel et al. 2011). Some isopods also occur under
stones in this level such as Sphaeroma serratum and species of the genera Cymodoce
and Dynamene. The hermit crab Clibanarius erythropus characteristically forms
dense aggregations among intertidal rocks and protects itself in shells of the local
gastropods (e.g. Cerithium lividulum). In the intertidal zone, the gap under loose
rock slabs and the fissures of the bedrock constitute a refuge from desiccation and
predation and are the home of many species such as decapods (e.g. Porcellana
platycheles; the crabs Xantho poressa, Eriphia verrucosa and Pilumnus hirtellus; the
prawn Athanas nitescens), many molluscs (e.g. Steromphala racketti, Ocinebrina
edwardsii, Columbella rustica, Striarca lactea, Cardita calyculata), polychaetes
(mainly serpulids) and sessile invertebrates such as colonial tunicates or sponges.
Occasionally conditions are met for some species of the infralittoral, like the urchin
Paracentrotus lividus and the sea anemone Anemonia viridis, forming “enclaves” in
rock pools on under large slabs (Templado et al. 2012).
In some areas, the so-called vermetid reefs (Fig. 9.6) are formed by the sessile
gastropod Dendropoma lebeche (formerly known as D. petraeum) whose dense
aggregates are being filled and cemented by the encrusting calcareous alga
Neogoniolithon brassica-florida. These are found in the Strait of Gibraltar and
reach their maximum development in the coasts of Alicante, Murcia and Almería
and in the Chafarinas Islands (Guallart and Calvo 2006; Guallart and Afán 2013) but
surprisingly show a large gap in the coast of Málaga, even in rocky areas. The
crevices and hollows inside the vermetid reef provide shelter to numerous organisms, such as polychaetes, the gastropod Fossarus ambiguus, the bivalves Lasaea
adansoni and Leiosolenus aristatus, the sipunculid Phascolosoma stephensoni or the
intertidal fish Coryphoblennius galerita, the latter using the cavities to harbour its
spawn (Moreno 2006).
All rocky shores can theoretically fit the loose concept of Habitat 1170 “Reefs” as
defined in the EU Habitats Directive (92/43/EEC) (see Templado et al. 2009), but
intertidal rocky shores are seldom claimed as such in Nature 2000 reports. Nevertheless, much of the intertidal rocky shore is comprised in several of the existing
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J. L. Rueda et al.
trochids and the false limpet Siphonaria pectinata, a pulmonate mollusc convergent
in shape with the true limpets; the polyplacophoran Lepidochitona caprearum is also
frequent. The mussels (Mytilus galloprovincialis and Perna perna) form mixed
aggregations where wave action is sufficient, and the sea anemone Actinia equina
is also a conspicuous element in shaded areas of exposed sites. At the lower levels
among the algal turf, the fauna is very diverse, and there are many other small
species of different groups. Molluscs are quite thoroughly studied (Gofas et al.
2011), and the most characteristic species in the midlittoral algal turf are Skeneopsis
planorbis, Nodulus spiralis, Pisinna glabrata, Tricolia miniata, and Cassiella
abylensis, the latter an endemic species of the Strait of Gibraltar. Other groups
(pycnogonids, amphipods, copepods, isopods, polychaetes, tanaids, insect larvae,
ostracods, mites, nematodes, ophiuroids, echinoids, sponges, bryozoans and foraminifera) are also diverse but not studied in detail yet. A study about gammarid
amphipods inhabiting intertidal seaweed of Tarifa found a distinct vertical segregation of the species (Krapp-Schickel et al. 2011). Some isopods also occur under
stones in this level such as Sphaeroma serratum and species of the genera Cymodoce
and Dynamene. The hermit crab Clibanarius erythropus characteristically forms
dense aggregations among intertidal rocks and protects itself in shells of the local
gastropods (e.g. Cerithium lividulum). In the intertidal zone, the gap under loose
rock slabs and the fissures of the bedrock constitute a refuge from desiccation and
predation and are the home of many species such as decapods (e.g. Porcellana
platycheles; the crabs Xantho poressa, Eriphia verrucosa and Pilumnus hirtellus; the
prawn Athanas nitescens), many molluscs (e.g. Steromphala racketti, Ocinebrina
edwardsii, Columbella rustica, Striarca lactea, Cardita calyculata), polychaetes
(mainly serpulids) and sessile invertebrates such as colonial tunicates or sponges.
Occasionally conditions are met for some species of the infralittoral, like the urchin
Paracentrotus lividus and the sea anemone Anemonia viridis, forming “enclaves” in
rock pools on under large slabs (Templado et al. 2012).
In some areas, the so-called vermetid reefs (Fig. 9.6) are formed by the sessile
gastropod Dendropoma lebeche (formerly known as D. petraeum) whose dense
aggregates are being filled and cemented by the encrusting calcareous alga
Neogoniolithon brassica-florida. These are found in the Strait of Gibraltar and
reach their maximum development in the coasts of Alicante, Murcia and Almería
and in the Chafarinas Islands (Guallart and Calvo 2006; Guallart and Afán 2013) but
surprisingly show a large gap in the coast of Málaga, even in rocky areas. The
crevices and hollows inside the vermetid reef provide shelter to numerous organisms, such as polychaetes, the gastropod Fossarus ambiguus, the bivalves Lasaea
adansoni and Leiosolenus aristatus, the sipunculid Phascolosoma stephensoni or the
intertidal fish Coryphoblennius galerita, the latter using the cavities to harbour its
spawn (Moreno 2006).
All rocky shores can theoretically fit the loose concept of Habitat 1170 “Reefs” as
defined in the EU Habitats Directive (92/43/EEC) (see Templado et al. 2009), but
intertidal rocky shores are seldom claimed as such in Nature 2000 reports. Nevertheless, much of the intertidal rocky shore is comprised in several of the existing
296
J. L. Rueda et al.