JOHNSTON: CAYMAN ISLAND AVIFAUNA


FIGURE 8.-Black and white mangrove forest, Grand Cayman.


on Grand Cayman (Figs. 9 and 10). Important introduced grasses of
these pastures are Guinea grass (Panicum maximum) and Seymour grass
(Andropogon metusus), and there are also scattered shrubs, such as
Comocladia dentata and trees such as Bursera simaruba, Roystonea sp.,
and Mangifera indica. Maintenance of the pastures (i.e., the arresting of
natural secondary succession to a woody community) is effected chiefly
by sporadic man-made fires. These small, scattered fires are important,
though not essential, ingredients in stirring up insects for anis, egrets,
and swallows.
 LOcwoOD FOREST OR SCRUB WOODLAND.-Pastures and other cleared
areas, if not maintained as such, quickly revert to a woody community
with the invasion of a variety of plants (Fig. 11). The latter include
maiden plum, red birch, and especially the introduced logwood (Haema-
toxylon campechianum). Open and, later, dense stands of nearly pure
logwood develop and are common on Grand Cayman on drier upland
sites (Fig. 12). Local people often refer to the dense logwood as "scrub
woodland." These stands, depending upon their age and other variables
(soil and water), frequently include in later stages thatch palm (Thrinax
argentea) and red birch, the combination woodland averaging about 6 m
in height and forming a nearly impenetrable forest (Fig. 13). This
formation is restricted to Grand Cayman and is most frequent in the
middle section of the island.