22
W.D. Heyman and B. Kjerfve
Important habitats within the Gulf are sandy beaches and mud-dominated areas at the mouth of the Sarstoon River, which contain the most
valuable shrimp fishery in the Gulf. Sand beaches on the Belize coast, within the inner and barrier reef cays, in Punta Manabique, and along the coast
of Honduras provide nesting areas for endangered green (Chelonia
mydas), hawksbill (Eretmochelys imbricata) , and some leatherback turtles
(Dermochelys coriacea). Loggerhead turtles (Caretta caretta) are seen in
coastal waters but generally nest further to the north. However, with the
exception of these habitats, the 70-km-long Maya Mountain Marine Area
Transect (MMMAT) includes the main coastal forms within the Gulf of
Honduras (Heyman 1996; Heyman and Kjerfve 1999; Figs. 1.1, 1.3). The
terrestrial area can be divided into the Maya Mountains, karstic limestone
relief (Fig. 1.3A), hilly to undulating lowlands (Fig. 1.3B), and coastal flat
lands which are highly varied in geologic and soil composition and contain
patches of pine forests, open savannas, broadleaf forests, and swamp
forests.
1.3.1 Coastal Lagoons
At the coast, rising sea level has resulted in inundation of flat coastal areas,
leading to formation of expansive coastal lagoons (Fig. 1.3C). TheY cacos
Lagoon is perhaps the best example of this habitat type, and includes a vast
complex of dwarf and tall red mangroves (Rhizophora mangle; Fig. 1.3D)
lining channels and creeks and expansive areas of shallow (1-2m) open
water with a mud bottom. The fringes of the creeks are colonized by taller
red mangroves, with dwarf mangroves behind and in the shallow basins.
The basins are separated from the coastal embayment by a thin siliceous
sand berm (Fig. 1.3E). Buttonwood (Conocarpus erectus), white mangrove
(Laguncularia racemosa), and black mangrove (Avicennia germinans) are
also present on areas of slightly higher ground. The mangrove leaf litter
contributes importantly to biotic production. Litter production reaches
1,187 and 1,570 g dry weight per m 2 per year at two river mouth sites and
is thus more productive than many riverine mangrove sites in the Caribbean (Heyman 1996). The coastal lagoons serve as critical nursery habitats
for a variety of marine and coastal species of fish and invertebrates. The
mud bottom habitat provides for bottom dwelling crustaceans and mollusks, which serve as food for benthic feeding rays, fish, and birds. Cownose rays (Rhinoptera sp.) are rare or absent in the rest of Belize but aggregate during January and February in the Y cacos Lagoon. Permit fish
(Trachinotus falcatus) also feed in the lagoon. The mangrove creeks provide refuge for juvenile fishes of many species, large black snappers (Lutja-
W.D. Heyman and B. Kjerfve
Important habitats within the Gulf are sandy beaches and mud-dominated areas at the mouth of the Sarstoon River, which contain the most
valuable shrimp fishery in the Gulf. Sand beaches on the Belize coast, within the inner and barrier reef cays, in Punta Manabique, and along the coast
of Honduras provide nesting areas for endangered green (Chelonia
mydas), hawksbill (Eretmochelys imbricata) , and some leatherback turtles
(Dermochelys coriacea). Loggerhead turtles (Caretta caretta) are seen in
coastal waters but generally nest further to the north. However, with the
exception of these habitats, the 70-km-long Maya Mountain Marine Area
Transect (MMMAT) includes the main coastal forms within the Gulf of
Honduras (Heyman 1996; Heyman and Kjerfve 1999; Figs. 1.1, 1.3). The
terrestrial area can be divided into the Maya Mountains, karstic limestone
relief (Fig. 1.3A), hilly to undulating lowlands (Fig. 1.3B), and coastal flat
lands which are highly varied in geologic and soil composition and contain
patches of pine forests, open savannas, broadleaf forests, and swamp
forests.
1.3.1 Coastal Lagoons
At the coast, rising sea level has resulted in inundation of flat coastal areas,
leading to formation of expansive coastal lagoons (Fig. 1.3C). TheY cacos
Lagoon is perhaps the best example of this habitat type, and includes a vast
complex of dwarf and tall red mangroves (Rhizophora mangle; Fig. 1.3D)
lining channels and creeks and expansive areas of shallow (1-2m) open
water with a mud bottom. The fringes of the creeks are colonized by taller
red mangroves, with dwarf mangroves behind and in the shallow basins.
The basins are separated from the coastal embayment by a thin siliceous
sand berm (Fig. 1.3E). Buttonwood (Conocarpus erectus), white mangrove
(Laguncularia racemosa), and black mangrove (Avicennia germinans) are
also present on areas of slightly higher ground. The mangrove leaf litter
contributes importantly to biotic production. Litter production reaches
1,187 and 1,570 g dry weight per m 2 per year at two river mouth sites and
is thus more productive than many riverine mangrove sites in the Caribbean (Heyman 1996). The coastal lagoons serve as critical nursery habitats
for a variety of marine and coastal species of fish and invertebrates. The
mud bottom habitat provides for bottom dwelling crustaceans and mollusks, which serve as food for benthic feeding rays, fish, and birds. Cownose rays (Rhinoptera sp.) are rare or absent in the rest of Belize but aggregate during January and February in the Y cacos Lagoon. Permit fish
(Trachinotus falcatus) also feed in the lagoon. The mangrove creeks provide refuge for juvenile fishes of many species, large black snappers (Lutja-