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24 Contributions to the Study of Biological Diversity Vol. 3 mangle L. (Red Mangrove, Mangro) trees which may also reach heights of 30 meters or more. Farther to the southeast and inland from Almond Beach, the coastal forests are presumably older, and more diverse. The third major mangrove species of the Neotropics, Laguncularia racemosa (L.) C.F. Gaertn. (White Mangrove, Kayara), does not often reach the stature of Avicennia or Rhizophora trees in the Guianas, but it was common as an understory shrub or treelet, as well as along the margins of coastal lagoons. Laguncularia has been observed in Guyana and other countries to be a very successful colonizer of swamps following disturbances (Baldwin et al. 2001; Delgado et al. 2001; Elster 2000; Roth 1992; Woodroffe 1983). The final dominant component of the mangrove swamp understory included two species of Acrostichum (Mangrove Fern, Monkey Bush). Those are similar, large terrestrial ferns; Acrostichum aureum L. was common throughout the mangrove swamps, while Acrostichum danaeifolium Langsd. & Fisch. is occasional in more inland locations. Either can become very dense in Mixed Mangrove swamp. The mangrove associate Conocarpus erectus L. was found on chenier ridges within the swamps and sometimes in the shrubby thickets along coastal lagoons and back beaches. As is typical for mangrove swamps around the world, the Avicennia swamps near the coast have a fairly open understory (Janzen 1985; Lugo 1986; Snedaker & Lahmann 1988), allowing easy walking, particularly during dry seasons. Mangrove swamps along Guyana’s Atlantic coast are well developed where they have been undisturbed by agriculture or urban development (Bacon 1990; Vann 1959, 1969; Wells & Coleman 1981). In places beach ridges separate swamps from tidal inundation, although waves at high tide often wash over narrower beach ridges and directly into the mangrove swamp. Those swamps behind beach ridges can also be referred to as occluded swamps, due to their separation from the sea. Such conditions have been documented in a few cases in the both the Neotropics (Lugo 1981; Stoddart et al. 1973; Vegas Vilarrúbia & Rull 2002; Woodroffe 1983) and the old world (Fosberg 1947; Steenis 1984; Woodroffe 1988). Within the classification of Lugo and Snedaker (1974) those swamps fall into the category of Basin Mangrove, and in some areas fit the classification of Hammock mangrove forest, a category added by Lugo (1980). Inlets into tidal streams are infrequent on the Waini Peninsula and can become blocked by sediment deposits, forming lagoons behind beach ridges. The Coastal Mangrove swamps of the Guianas do not conform to the zonation pattern typically described for the low sediment swamps of the Caribbean, in which Rhizophora occupies the position closest to the sea, with Avicennia as a back mangrove species followed by Laguncularia and Conocarpus as species of the transition to freshwater swamp or upland. A pattern of zonation similar to that on the Waini Peninsula was also reported for the Wia Wia Bank in northeastern Surinam by Lindeman (1953), though he noted an absence of Conocarpus. That arrangement was also confirmed for French Guiana by Fromard (1998). There Laguncularia was reported to be at least as common as Avicennia in the pioneer coastal communities, though Avicennia still became the dominant species of mature coastal swamps. - Mixed Freshwater Swamps Towards the interior of the Waini Peninsula, the Coastal Mangrove swamp plant community graded into Mixed Freshwater swamp. The length of that transition varied but usually spanned one to two kilometers. In that zone, occasional Avicennia germinans (L.)Stearn trees and Rhizophora trees persist, usually as large individuals. The Mixed Freshwater swamp group was divided into two subsets, Ficus - Euterpe forest and Pterocarpus forest (Figure 1.13), which was mixed with several other tree and understory species. Ficus spp. trees were a significant component of the Ficus-Euterpe portion, particularly large Ficus amazonica (Miq.) Miq., of which several individuals survived the 1997-1998 soil fires in places where all other trees were killed. Individuals of Ficus eximia Schott, a similar member of the Ficus citrifolia group may also occur on the Waini Peninsula. In the center of the peninsula, parts of the swamp had been dominated by Euterpe cf. oleracea Mart. (Manicole palm) with scattered Ficus. In sections surveyed, all Euterpe
Contributions to the Study of Biological Diversity Vol. 3 trees had been killed by the recent fires, leaving numerous fallen trunks. After the fires those areas were very open and dominated by a mosaic of vines, Typha, sedges, and various herbs. During wet periods, scattered shallow pools with floating vegetation were common there. The species richness of the Mixed Freshwater swamp increased in the Pterocarpus forest zone up to the transition to Riverine Mangrove swamps along the Waini River, in forests where Pterocarpus officinalis Jacq. (Corkwood) was common. Just before entering the Riverine Mangrove swamp, there was a belt dominated by Pterocarpus mixed with occasional, extremely large Avicennia germinans trees, some of which measured over two meters dbh (Figure 1.16); small Avicennia trees or seedlings were not common in that area. Some of these exceed the size of Avicennia trees at Maranhão, Brazil, reported by Lacerda et al. (2002) to grow in excess of one meter dbh. Fromard (1998) described a similar species Figure 1.16. Mixed Freshwater forest near the transition to Riverine Mangrove forest. This Avicennia germinans tree was measured at over 2 meters dbh, though it was not measured above the buttresses. Pterocarpus officinalis trees were also found in this zone near the Waini River. 25 zonation in French Guiana, moving inland up the rivers from Coastal Mangroves towards Euterpe and Pterocarpus forest with fewer, but very large, Avicennia and Rhizophora trees, which he attributed to increasing influence of riverine rather than tidal hydrology. The trees Machaerium lunatum (L. f.) Ducke, Inga ingoides (Rich.) Willd., Zygia latifolia (L.) Fawc. & Rendle and Clusia palmicida Rich. ex Planch. & Triana were occasional in the Mixed Freshwater swamps, particularly in Pterocarpus zones. There the understory included Cassipourea guianensis Aubl., Ilex guianensis (Aubl.) Kuntze and Malouetia tamaquarina (Aubl.) A. DC., as well as several species of ferns including Blechnum serrulatum Rich., Pteris pungens Willd., and Nephrolepis biserrata (Sw.) Schott. Vines and lianas noted in those swamps included Monstera adansonii Schott, Syngonium podophyllum Schott, and Hippocratea volubilis L. as well as several vines that had become dominant in the burned swamp including Cissus verticillata (L.) Nicolson & C.E. Jarvis, and Cydista aequinoctialis (L.) Miers. While trees in the Coastal Mangrove swamps were host to few epiphytes, probably due to salinity from the ocean, several epiphytic species were found in the Mixed Freshwater swamps, including the bromeliads Aechmea nudicaulis (L.) Griseb. and Guzmania lingulata (L.) Mez, the cactus Rhipsalis baccifera (J.S. Muell.) Stearn, and the orchids Epidendrum ciliare L. and Prosthechea aemula (Lindl.) Higgins. Some epiphytic species were recorded in the Mixed Freshwater forest only as survivors on the branches of fallen trees killed by fires, including the cactus Epiphyllum phyllanthus (L.) Haw. and the orchid Trichocentrum lanceanum (Lindl.) M.W. Chase & N.H. Williams. An unexpected feature of the Mixed Freshwater swamps was the isolated population of Roystonea oleracea (Jacq.) O.F. Cook, consisting of perhaps 120 scattered individuals of all sizes (Figure 1.17). That population survived the 1998 soil fires while most surrounding vegetation was killed except for a few large Ficus trees. Prior to the documentation of that population, no species of the genus Roystonea had been recorded in the Guianas outside of cultivation (Zona 1996). The remote
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130 Ipomoea violacea L. Merremia ci
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138 Guatteria flexilis R.E. Fr. Gua
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142 Diospyros tetrandra Hiern Elaeo
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144 Aniba hostmanniana (Nees) Mez A
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148 Rhizophora racemosa G. Mey. Con
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150 Turneraceae Turnera scabra Mill
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158 Asplundia glandulosa (Gleason)
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160 Bellucia grossularioides (L.) T
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162 Psychotria wessels-boeri Steyer
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164 Celastraceae Elaeodendron xyloc
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