Plant Community Structure, Fire Disturbance, and Recovery in ...

More documents

Recommendations

Info

50 Contributions to the Study of Biological Diversity Vol. 3 that relationship has been refuted by recent molecular studies that place Nypa as a basal group sister to all other palms (Lewis & Doyle 2001) or basal if excluding the subfamily Calamoideae (Asmussen & Chase 2001), which includes the Moriche or Ité Palm Mauritia, a distinctive feature of the vegetation of the Venezuelan Llanos and the coastal plain swamps of Guyana. NYPA FRUTICANS OUTSIDE OF ITS MODERN NATIVE RANGE Nypa fruticans has become a widespread exotic species in some estuaries of Western Africa, where it was introduced in the early 20 th century, particularly in the Niger Delta (Sunderland & Morakinyo 2002; Ukpong 1995). Duke (1991) first documented Nypa in the modern Neotropics from a small population at the mouth of Panama’s Rio Majugual, in the Figure 3.1. Map of northwestern Guyana, showing the known range of Nypa, from personal observations during river travel. The Guiana current flows in the direction of the Orinoco Delta and Trinidad. vicinity of the Caribbean seaport Colón, near the northern, Caribbean end of the Panama Canal. More recently, viable Nypa fruits have been reported from beaches of Trinidad by Bacon (2001), who successfully germinated some of these stranded fruits in the laboratory. An initial account of Nypa populations along the rivers of the Northwest District of Guyana was given by Pritchard (1993), whose published segment on Nypa went largely unnoted within his general review of palms in Guyana. That knowledge of Nypa’s presence in Guyana has not been applied to subsequent discussions of Nypa in the Neotropics. In light of the increasing attention to the presence of Nypa outside of its native range and of its environmental implications, there is a need for further description and documentation of the populations established in Guyana. Nypa’s presence in Guyana also has bearing on recent speculation about the origin of Nypa propagules found stranded on beaches in Trinidad (Bacon 2001). From 1997 to 2001, during investigations of coastal Avicennia germinans swamps in Northwestern Guyana, Nypa palms were observed along the banks of the Waini River as far as 42 kilometers upstream from the river’s mouth. These colonies are thickest over most of the length of the Mora Passage, a connector between the Waini and the Barima Rivers. Nypa also grows along the Barima River from the Mora Passage to the Aruka River, and on the Aruka River as far upstream as the district administrative seat, Mabaruma. It is very likely that Nypa is present in Venezuela downstream along the Barima River as it flows towards the southern Orinoco Delta. Smaller colonies of Nypa, mentioned by Pritchard (1993), still exist on the Pomeroon River upstream nearly to the town of Charity. The currently observed range of Nypa in Guyana is shown in Figure 3.1. Even the densest areas of Nypa along the Mora Passage (Figure 3.2) are mixed with the riverine red mangrove Rhizophora racemosa G. Figure 3.2. Nypa growing along the banks of the Mora Passage, interspersed with the prop-rooted riverine red mangrove Rhizophora racemosa.
Contributions to the Study of Biological Diversity Vol. 3 Mey., although Nypa sometimes dominates the river’s fringe. Nypa is often scattered in the understory of the intertidal Rhizophora racemosa swamp. Nypa infructescences up to 25 cm in diameter, composed of approximately Figure 3.3. A Nypa infructescence collected as part of Hollowell et al. #213, from along the banks of the Mora Passage. 70 fruits (Figure 3.3), are common in these populations. When mature, the spherical heads break up, and the viviparous fruits disperse with the currents. As part of recent fieldwork in the region a voucher collection of Nypa fruticans Figure 3.4. Label information for the voucher collection of Nypa fruticans in the Northwest District of Guyana, as distributed with specimens. was made along the Mora Passage (Figure 3.4). Along the ocean beaches of the Waini Peninsula, germinated propagules are occasionally found stranded (Figure 3.5), similarly to those documented recently in Trinidad by Bacon (2001). Established Nypa plants have never been observed during many walks and boat trips along this part of Guyana’s 51 Atlantic coast. The entire coast of the Guianas is bordered by extensive mudflats, derived primarily from Amazon River sediments (Brinkman & Pons 1968; Gibbs & Barron 1993). This coastal habitat is apparently inhospitable to Nypa, possibly due to wave energy and the shifting nature of the mudflats. Neither has Nypa been seen in the Avicennia dominated mangrove swamps immediately behind the low coastal beach ridges along the Atlantic coast, and it is uncertain whether that habitat would be amenable to Nypa. DISPERSAL OF NYPA TO TRINIDAD Bacon (2001) suggested the possibility that Nypa fruticans propagules found stranded on beaches in Trinidad originated from known populations in West Africa and were dispersed by prevailing currents across the Atlantic ocean and north along the eastern coast of South America. In one day, along a 500 meter stretch of Manzanilla Beach in eastern Trinidad, Bacon and students collected a total of 53 Nypa propagules, including 12 viable propagules (Bacon 2001), which would be extraordinary if attributable to trans-Atlantic dispersal. Considering the trans-Atlantic distribution of several mangrove taxa, successful dispersal and establishment over these distances might occur rarely. However, the Atlantic Ocean is a formidable barrier (Duke et al. 2001), and Figure 3.5. A viable Nypa propagule found stranded on the beach of the Waini Peninsula, approximately 5 km east of Waini Point. The beach is composed of small shell fragments; off the beach mudflats extend seaward for several kilometers.
Page 1 and 2: CENTRE FOR THE STUDY OF BIOLOGICAL
Page 3 and 4: CONTENTS INTRODUCTION .............
Page 5: Dispersal in Mangrove Swamps ......
Page 8 and 9: 8 Contributions to the Study of Bio
Page 10 and 11: 10 Contributions to the Study of Bi
Page 42 and 43: 42 4004 54.10% 713 53.09% 72 61.54%
Page 100 and 101:
100 Contributions to the Study of B
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
130 Ipomoea violacea L. Merremia ci
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
138 Guatteria flexilis R.E. Fr. Gua
Page 140 and 141:
Page 142 and 143:
142 Diospyros tetrandra Hiern Elaeo
Page 144 and 145:
144 Aniba hostmanniana (Nees) Mez A
Page 146 and 147:
Page 148 and 149:
148 Rhizophora racemosa G. Mey. Con
Page 150 and 151:
150 Turneraceae Turnera scabra Mill
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
158 Asplundia glandulosa (Gleason)
Page 160 and 161:
160 Bellucia grossularioides (L.) T
Page 162 and 163:
162 Psychotria wessels-boeri Steyer
Page 164 and 165:
164 Celastraceae Elaeodendron xyloc
Page 166:
show all

Plant Community Structure, Fire Disturbance, and Recovery in ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?