270
J.R. Cantera and J.F. Blanco
me rate rocks and sandstone substrates. Among crustaceans, only the ghost
shrimp Upogebia tenuipollex ( 126 in d. m- 2 ) contributes to bioerosion of
the rocky cliffs. By removing sediments from the cliff base, boring organisms form large cavities that weaken the base and cause the upper part to
slide. Depending on the impact of storm waves, tides, and ENSO events,
erosion rates in exposed areas may vary between 300 cm 3 m- 2 month-' for
igneous rocky cliffs and 450 cm 3 m- 2 month-' for sedimentary rocky cliffs
(Canter a et al. 1998). Several of the rocky islands and peninsulas originated
from intense bioerosion of the northern shore of Buenaventura Bay.
18.3.3 Mangrove Swamps
Mangrove habitats in Buenaventura Bay are comprised of the red mangroves Rhizophora mangle and R. racemosa (Rhizophoraceae), the black mangroves Avicennia germinans and A. tonduzii (Avicenniaceae), the white
mangroves ("comedero") Laguncularia racemosa and Conocarpus erecta
(Combretaceae), the "Pifiuelo" Pellicera rhizophorae (Theaceae), and the
"Nato" Mora oleifera (Caesalpinaceae). These species are distributed along
environmental gradients, like tidal range, wave exposure, sediment deposition, soil characteristics, microtopography, salinity and nutrients.
According to the classification by Cintron and Schaeffer-Novelli (1983),
the mangrove habitats can be divided into three different physiographic
types. Riverine mangroves are well developed (<35m height, <20 em dbh,
-100 trees per 0.1 ha) along tidal creeks and in the estuarine zone of rivers
at the southern shore of the bay. Red and black mangroves colonize the
unstable substrate near the sea front, whereas Pellicera rhizophorae and
Mora oleifera occupy consolidated substrates (Fig. 18.2a). Bar mangroves
grow behind sand ridges at Soldado Island near the mouth of the bay
(<15m height, <6 em dbh, 185-766 trees per 0.1 ha). Red mangroves occupy unstable muddy substrates, while black and white mangroves colonize
more stabilized sandy ridges (Fig. 18.2b ). The fringe mangroves of protected areas along the northern shore of the bay occupy platforms resulting from bioerosion of sedimentary cliffs. Usually fringe mangroves develop slowly or are dwarfed, but exceptionally they exhibit development
similar to riverine mangroves ( <6-9 m height, 4-11 em dbh, 10-250 trees
per 0.1 ha). The unstable substrate of the frontal zone of platforms is colonized by red mangroves and Pellicera rhizophorae is present on stable
internal platforms (Fig. 18.2 c; Blanco et al. 1998).
Mangrove habitats offer niches for benthic macroalgae and animals,
though few species are restricted to these habitats. Several green algae
grow on prop roots (Chaetomorpha californica), pneumatophores (Bood-
J.R. Cantera and J.F. Blanco
me rate rocks and sandstone substrates. Among crustaceans, only the ghost
shrimp Upogebia tenuipollex ( 126 in d. m- 2 ) contributes to bioerosion of
the rocky cliffs. By removing sediments from the cliff base, boring organisms form large cavities that weaken the base and cause the upper part to
slide. Depending on the impact of storm waves, tides, and ENSO events,
erosion rates in exposed areas may vary between 300 cm 3 m- 2 month-' for
igneous rocky cliffs and 450 cm 3 m- 2 month-' for sedimentary rocky cliffs
(Canter a et al. 1998). Several of the rocky islands and peninsulas originated
from intense bioerosion of the northern shore of Buenaventura Bay.
18.3.3 Mangrove Swamps
Mangrove habitats in Buenaventura Bay are comprised of the red mangroves Rhizophora mangle and R. racemosa (Rhizophoraceae), the black mangroves Avicennia germinans and A. tonduzii (Avicenniaceae), the white
mangroves ("comedero") Laguncularia racemosa and Conocarpus erecta
(Combretaceae), the "Pifiuelo" Pellicera rhizophorae (Theaceae), and the
"Nato" Mora oleifera (Caesalpinaceae). These species are distributed along
environmental gradients, like tidal range, wave exposure, sediment deposition, soil characteristics, microtopography, salinity and nutrients.
According to the classification by Cintron and Schaeffer-Novelli (1983),
the mangrove habitats can be divided into three different physiographic
types. Riverine mangroves are well developed (<35m height, <20 em dbh,
-100 trees per 0.1 ha) along tidal creeks and in the estuarine zone of rivers
at the southern shore of the bay. Red and black mangroves colonize the
unstable substrate near the sea front, whereas Pellicera rhizophorae and
Mora oleifera occupy consolidated substrates (Fig. 18.2a). Bar mangroves
grow behind sand ridges at Soldado Island near the mouth of the bay
(<15m height, <6 em dbh, 185-766 trees per 0.1 ha). Red mangroves occupy unstable muddy substrates, while black and white mangroves colonize
more stabilized sandy ridges (Fig. 18.2b ). The fringe mangroves of protected areas along the northern shore of the bay occupy platforms resulting from bioerosion of sedimentary cliffs. Usually fringe mangroves develop slowly or are dwarfed, but exceptionally they exhibit development
similar to riverine mangroves ( <6-9 m height, 4-11 em dbh, 10-250 trees
per 0.1 ha). The unstable substrate of the frontal zone of platforms is colonized by red mangroves and Pellicera rhizophorae is present on stable
internal platforms (Fig. 18.2 c; Blanco et al. 1998).
Mangrove habitats offer niches for benthic macroalgae and animals,
though few species are restricted to these habitats. Several green algae
grow on prop roots (Chaetomorpha californica), pneumatophores (Bood-