the Bay of Rest is a general feature. The finding of Day (1975) that the fauna of
a seaward lagoon was several times as rich in species as an adjoining mangrove
area has already been mentioned. A number of authors have reported that few
species of invertebrates actually live in the mud in mangroves; the species collected
are usually epifaunal or live on the trees. Berry (1963) and Sasekumar (1974)
reported a virtual absence of burrowing species, except crustaceans. Brown (1971)
found a gastropod, Auriculastra radiolata, living in the mud and commented that
he could find no other reference in the literature to in faunal gastropods in mangroves.
The most pertinent study is that of Kolehmainen and Hildner (1975).
They examined the distribution of invertebrates in a Puerto Rican swamp of the
red mangrove, Rhizophora mangle. Tide range is low in the Caribbean and the
seaward trees have aerial proproots extending into channels. These roots, at least
in their lower portions, are continuously submerged. Kolehmainen and Hildner
reported that these aerial roots had a mean dry weight biomass of invertebrates
of 55.2 glm2; no such aerial root system occurred in the Bay of Rest. A berm
zone 1 to 3 m into the mangroves, where the roots are anchored in the substrate
had a biomass of 94.5 glm2, the highest level recorded in the tree zones. Further
into the trees the biomass of invertebrates declined sharply, and no invertebrates
were found in the center of the mangroves. This situation parallels the results
found in the Bay of Rest. Kolehmainen and Hildner (1975) also found that the
embayment seaward of the mangroves had an invertebrate biomass four times
as great as that of the richest tree zone, a situation that is similar to the Bay of
Rest except for the predominance of T. sulcata in the A. marina zone.