rocky shores

• The interface between sea and land, with large particle size (rocks rather than sand)

Subdivisions include supralittoral, eulittoral and sublittoral - Supralittoral: above the high-tide mark and is usually not under water - Eulittoral: breaking waves to a depth of 5 to 10 metres (16 to 33 feet) below the low-tide - Sublittoral: beyond the low-tide mark and is often used to refer to substrata of the continental shelf, which reaches depths of between 150 and 300 metres.

• Species diversity • Habitat complexity and species diversity • Interspecific competition

between individuals of different species

• Defined by distance from the low tide position • All rocky shore species are marine so unable to survive indefinitely out of water • Tolerance to desiccation influences upper limits- movement, shell morphology, metabolic rates • Biological pressures influence lower limits- predation, competition

• Defined by distance from the low tide position • All rocky shore species are marine so unable to survive indefinitely out of water • Tolerance to desiccation influences upper limits- movement, shell morphology, metabolic rates • Biological pressures influence lower limits- predation, competition

• Particle size- Varies greatly due to wave action and substrate (deposition vs erosion), Species diversity is highest for median levels of disturbance • Salinity- Most marked in estuaries and rock pools, Some hypersaline due to evaporative loss, Others have low salinity levels due to rainfall/ runoff

• Primary producers • Suspension feeders • Grazers • Predators

Algae, lichens and cyanobacteria

• Microalgae -Biofilms: cyanobacteria, macro-algae spores and diatoms • Simple algae (filamentous and foliose) -Short-lived with few defences from grazers • Complex algae (canopy forming)-Red, green and brown, Some protection from grazing • Encrusting algae- Calcifying (CaCO3 )

• Individuals: Barnacles, mussels and solitary ascidians • Colonial: Polychaetes, bryozoans, sponges and ascidians

• Barnacles – strainers. Much variation in size (e.g. Megabalanus). Global • Mussels – siphonal. Mytilus & modiolus are global. • Large solitary ascidians (sea squirts). Subphlylum Tunicates are found Australia, S. Africa & S. America

• Polychaetes – Sabellaria forms large structural mats • Bryozoans (Phylum) – Colonies can be encrusting or foliate • Sponges – body consists of flagellated cells which can draw in water • Ascidians – colonies join but avoid non-kin

• Sweepers: Topshells and nerites • Rakers: winkles, isopods, amphipods & grapsid crabs • Diggers & abraders: limpets, chitons and urchins • Biters & cutters: fish & majid crabs

• Trochidae – small primitive gastropods, wideglobal distribution. High diversity in tropics • Neritidae – tropical, can excavate rock • Rows of many small, blunt teeth to sweep up dislodged biofilm and detritus

• Littorinidae – Littorina obtusata on algae and Littorina littorea on rocks • Mega-grazing isopods and amphipods – density up to 10,000 m-2 • Grapsid crabs - herbivorous crabs more common in the tropics • Sharp teeth to dig into a bite off macroalgae

• Prosobranch limpets (gills & no lungs) e.g. Patellids. Worldwide. • Pulmonate limpets (lungs & secondary gills). Tropical • Chitons (Polylacophora). Global but more common in warm waters • Urchins (Echinoderms). Graze using Aristotle’s lantern • Hardened teeth dig into rock surface

• Majid crabs – chelids cut through algae (e.g. spider crabs) • Nudibranchs – some are rakers, others puncture algal cell walls

• Borers and drillers: Whelks • Crushers & crackers: (non-grapsid) crabs (Omnivorous) • External digesters: Starfish • Browsers & partial predators: Nudibranch molluscs • mobile vertebrates: Fish & birds • Sit & wait: Anemones & hydroids

• Prominent on rocky shores globally. • Proboscis effective - Bore into shells or push between shell plates, once through the shell, radula rasps upon soft tissues

• Portunidae (swimming crabs)- Fast-moving & aggressive with sharp chelae. • Cancridae (edible crabs) and Xanthidae (stone crabs; W. Atlantic only), Large, slow moving

• Found submerged in water • Tube feet to allow rapid (relatively) movement • Feed on bivalves, sea urchins, snails, barnacles and carrion • Everts stomach through mouth to engulf prey • Potential as keystone consumers i.e. could trigger a trophic cascade if removed

• Feed on sessile prey: Bryozoans, sponges, colonial ascidians, hydroids & soft corals • Huge diversity of body forms (>2,300 spp.) • Nudibranch radula apparently effective at removal

• Fish at high tides, birds at low tides • Highly active, not constrained by predator/ prey limitation • Fish- Wide range of taxa inc. blennies & gobies, Clingfish on limpets • Birds-Charadriiformes (waders & gulls), Passerines in supralittoral – some terrestrial