Puerto Rican dry forests (like
Caribbean dry forests in general) consist of short-stature (usually < tall), multi-stemmed trees. The canopy is largely evergreen (dominated by
Gymnanthes lucida in areas of limestone soil), while the emergent layer is considerably more dry-season deciduous.
Vegetation types Plant community types exist along a continuum of soil moisture availability, which is itself influenced by soil depth, and the orientation and the slope of the land (which affects
runoff). Coastal vegetation includes
mangrove, salt flats and beach thickets. Further inland, scrub forest grows on exposed limestone with scattered depressions. Deeper soils support deciduous forests with taller semi-evergreen forests growing on moister sites. The degree of deciduousness varies with water stress—drought–deciduous species retain more of their leaves in wetter years and lose more of them in drier years—and even in the deciduous forests, many trees are evergreen.
Guaiacum officinale,
Coccoloba venosa,
Ceiba pentandra, and
Capparis cynophallophora are common trees in coastal dry forests. Dry limestone forest species include
Pisonia albida,
Guaiacum sanctum, and
Plumeria alba.
Fauna Puerto Rican dry forest support a diverse avifauna; 185 bird species have been recorded in Guánica Forest including 15
endemic species. The endangered
Puerto Rican nightjar is restricted to dry and moist forests in southwestern Puerto Rico. The
Puerto Rican crested toad, the only native toad in Puerto Rico, is known from only one remaining population in Guánica Forest. Thirteen species of lizards are known from the southern dry forests including two
anole endemic to the dry forest zone-
Anolis poncensis and
Anolis cooki. The
Mona ground iguana is endemic to dry forest on the island of Mona. Non-native mammals in the dry forest zone include
rhesus macaques and
patas monkeys, both of which have become serious agricultural pests, and the
Javan mongoose which was introduced to Puerto Rico in the 1870s.
Conservation Although most of the forest was destroyed for
agriculture prior to the 1940s, some patches of forest which pre-date that period still exist. Areas that were used for
charcoal production or for fence-posts have recovered rapidly - after 50 years forests that had been used for charcoal production recovered to the point where they were indistinguishable from much older forests. In addition, large areas of
secondary forest have grown back on abandoned agricultural land. Unlike areas which were only lightly used, these forests on abandoned farmland have far fewer species than do natural forests. Their path to recovery remains uncertain. The best example of dry forests in Puerto Rico are in the
Guánica State Forest (
Bosque Estatal de Guánica) outside the town of
Guánica. This site has also been the focus of the vast majority of studies of dry forests. Other protected dry forests in Puerto Rico include the
Cabo Rojo,
Culebra,
Desecheo and
Vieques wildlife refuges (part of the
Caribbean Islands National Wildlife Refuge Complex), the
Caja de Muertos and the
Mona and Monito Islands Natural Reserves, among other smaller protected areas along the southern coast of the island. ==See also==