Download the publication - Tropenbos International

More documents

Recommendations

Info

Plant diversity in a Central African rain forest: Implications for biodiversity conservation in Cameroon Table 3.5 Summary of the number of species of the various growth forms recorded in 136 vegetative subplots of 5 m x 5 m each covering 0.34 ha. Forest types Floristic composition 50 Coastal Forest Swamps Forest rich in Caesalpinioideae Forest rich in Calpocalyx and Sacoglottis Mixed evergreen Submontane and semi-deciduous forest forest Trees 27 6 35 38 37 26 Shrubs/small trees 87 14 148 102 134 74 Herbs 88 14 142 98 105 77 Lianas 30 3 36 33 32 11 Total No of species 232 37 368 271 308 188 Total No of families 67 27 76 63 68 47 Table 3.6 Pearson correlation coefficients between the Shannon diversity (H’) of the various growth forms recorded for all vascular plants with DBH ≥ 1 cm in 145 plots of 0.1 ha each. Life forms Large trees Shrubs/small trees Herbs Lianas Large trees 1 Shrubs/small trees 0.47** 1 Herbs 0.46** 0.29** 1 Lianas 0.003 0.20* 0.19* 1 Pearson correlation is significant for * P < 0.05 and ** P < 0.01 the number of herbaceous species (Table 3.5), moving from 25 species (in 145 plots of 0.1 ha each) to 257 species (in 136 subplots of 25 m² each covering 0.34 ha).Trees and shrubs were the most diverse growth forms followed by lianas and herbaceous species respectively (Table 3.4). The Shannon diversity (H’) of trees varied from 3.96 (swamps) to 4.67 (submontane forest), for shrubs from 3.32 (coastal forests) to 4.66 (submontane forest) and for herbaceous species from 0.53 (coastal forests) to 1.03 (forest rich in Calpocalyx and Sacoglottis). There was a significant positive correlation between the number of large and medium sized tree species and that of shrubs/small trees (F1, 143 = 112.033, R² = 0.439, P < 0.001) and woody climbers (F1, 143 = 26. 986, R² = 0.159, P < 0.001). There was also a significant positive correlation between the diversity of large and medium sized trees and that of the shrubs/small trees and woody climbers (Figures 3.3 & 3.4). The correlations between the diversity/species richness of large and medium sized trees and that of the herbaceous species were not significant (F1, 143 = 0.001, R² = 0.00002, P = 0.975 for Shannon diversity and F1, 143 = 0.0387, R² = 0.0003, P = 0.844 for species richness). The Shannon diversity (H’) was significantly different among the various growth forms (F3, 34.6 = 151.290, P < 0.001) when correcting for differences in vegetation types (GLM: F10, 30 = 2.727, P < 0.01 for vegetation type included as a random factor). A Tukey multiple comparison test showed that all growth forms were significantly different from each other (P < 0.05) with trees having the highest mean value (H’ = 3.37) and the lowest (H’ = 0.24) for the herbaceous species.
Diversity patterns in the flora of the Campo-Ma’an rain forest, Cameroon: do tree species tell it all? The species richness was also significantly different between growth forms (GLM: F3, 33.2 = 221.889, P < 0.001 for layer and F10, 30 = 2.973, P < 0.01 for vegetation type included as a random factor), with similar relative difference. Overall, there was a decrease in diversity and the total number of species recorded/plots with decreasing sampling resolution (Figures 3.5 & 3.6). About 30% of the total number of species recorded was lost when the sampling design only took into account all vascular plants with DBH ≥ 5 cm and more than 50% were lost when only vascular plants with DBH ≥ 10 cm are collected. Moreover, there was a very strong significant positive correlation between the number of stems/ha and the total number of species recorded (R 2 = 0.956, P < 0.0001), and a considerable drop in diversity when the sampling was limited to all vascular plants with DBH ≥ 10 cm. In terms of sampling effort, less than 30% of the total number of stems/ha were recorded when the sampling design only took into consideration all vascular plants with DBH ≥ 5 cm. Furthermore, only 15% of the total number of stems/ha were recorded for all vascular plants with DBH ≥ 10 cm. Species richness within families Overall, shrubs/small trees show the highest number of families (75) followed by medium trees (61), herbs and hemi-epiphytes (58), large trees (54) and woody climbers (37). Rubiaceae was by far the most species rich family (204 species) followed by Euphorbiaceae (88), Leguminoseae-Caesalpinioideae (85), Annonaceae (63), Sterculiaceae (50), Apocynaceae (47) and Sapindaceae (40). Leguminoseae (especially the sub-family Caesalpinioideae) was the dominant family for the large trees species (DBH ≥ 30 cm) in terms of relative density and frequency in the Campo-Ma’an area (Table 3.7). Dominant large tree species included Brachystegia cynometroides, Calpocalyx heitzii, Desbordesia glaucescens, Erythrophleum ivorensis, Lophira alata, Lovoa trichilioides, Piptadeniastrum africanum, Pterocarpus soyauxii, Pycnanthus angolensis, Sacoglottis gabonensis and Terminalia superba. Common shrubs and small tree species included Jollydora duparquetiana, Lasianthera africana, Massularia acuminata, Podococcus barteri and many species of the genera Campylospermum, Cola, Crotonogyne, Diospyros, Drypetes, Microdesmis, Psychotria, Rinorea and Scaphopetalum. Common large woody climber species were from the genera Agelaea, Dichapetalum, Combretum, Laccosperma, Landolfia, Millettia, Salacia and Strychnos. The most important herb species were Costus englerianus, Haumania danckelmaniana, Leptaspis zeylanica, Marantochloa monophylla, Microcalamus barbinodis, Puella ciliata, P. schumanniana, and many species of the genera Asystasia, Begonia, Cercestis, Culcasia, Dorstenia, Geophila, Hymenocoleus, Mapania, and Palisota. 51
Page 3: Chapter 1 GENERAL INTRODUCTION Gild
Page 6 and 7: Plant diversity in a Central Africa
Page 21: Chapter 2 CENTRAL AFRICAN TROPICAL
Page 32 and 33: -2.0 Plant diversity in a Central A
Page 43: Chapter 3 DIVERSITY PATTERNS IN THE
Page 63: Chapter 4 BIO-INDICATOR SPECIES AND
Page 89: Chapter 5 BIODIVERSITY HOTSPOTS AND
Page 102 and 103:
Plant diversity in a Central Africa
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 115:
Chapter 6 GENERAL CONCLUSIONS AND I
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 127:
REFERENCES
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 139:
ANNEXES
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186:
Page 190 and 191:
SUMMARY Summary The fragile ecosyst
Page 192:
Summary suggest that the Campo-Ma
Page 196 and 197:
RESUME Résumé La biodiversité de
Page 198 and 199:
Résumé nombreux auteurs qui argum
Page 200:
SAMENVATTING Gildas Peguy Tchouto M
Page 203 and 204:
Page 205:
show all

Download the publication - Tropenbos International

Create successful ePaper yourself

Delete template?

Save as template?