Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-22T15:32:34.494Z Has data issue: false hasContentIssue false

Seed viability of Afromontane tree species in forest soils

Published online by Cambridge University Press:  10 July 2009

Demel Teketay
Affiliation:
Swedish University of Agricultural Sciences, Faculty of Forestry, Department of Forest Vegetation Ecology, S-901 83 Umeå, Sweden
Anders Granström
Affiliation:
Swedish University of Agricultural Sciences, Faculty of Forestry, Department of Forest Vegetation Ecology, S-901 83 Umeå, Sweden

Abstract

The fate of seeds of eight tree species was followed during 4 y of storage in the soil of an Afromontane forest at Gara Ades in the eastern highlands of Ethiopia. Seeds were enclosed in nylon mesh bags and buried at 5 cm soil depth. The bags were exhumed at intervals and the viability of the seeds was assessed by germination and cutting tests. Seeds of Bersama abyssinica and Ekebergia capensis germinated in the soil almost completely within a year after burial. The seeds of Juniperus procera, Olea europaea and Podocarpus falcatus also germinated to a substantial degree in the soil but with a distribution over several years, and some seeds of these species remained viable at the end of the 4-y period. Germination in the soil was very low in seeds of Acacia abyssinica and Croton macrostachyus throughout the whole burial period and the seeds kept their viability. In C. macrostachyus fresh seeds were highly dormant, but after 3 y or more in the soil they germinated readily in the laboratory suggesting an altered dormancy with time in the soil. Dormancy in seeds of A. abyssinica and Indigofera rothii was not altered throughout the study period as evidenced by marginal or no germination during incubation in the laboratory. The differential seed behaviour observed during storage in the soil can be an indicator of the regeneration strategy of the species studied. B. abyssinica, E. capensis, J. procera, O. europaea and P. falcatus form seedling banks on the forest floor and lack persistent soil seed reserves in contrast to A. abyssinica, C. macrostachyus and I. rothii which accumulate reserves of long-lived seeds in the soil. The generally high levels of dormancy and somewhat extended viability in the soil, even in several of the species producing seedlings in undisturbed forest, may have been selected for under a climate of seasonal drought and unreliable rainfall that characterizes this region.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

LITERATURE CITED

Anonymous. 1988. National atlas of Ethiopia. Ethiopian Mapping Authority, Addis Ababa. 77 pp.Google Scholar
Bazzaz, F. A. & Pickett, S. T. A. 1980. Physiological ecology of tropical succession: a comparative review. Annual Review of Ecology and Systematics 11:287310.CrossRefGoogle Scholar
Brokaw, N. V. L. 1985. Treefalls, regrowth, and community structure in tropical forests. Pp. 5359 in Pickett, S. T. A. & White, P. S. (eds). The ecology of natural disturbance and patch dynamics. Academic Press, Inc., New York. 472 pp.Google Scholar
Cohen, D. 1968. A general model of optimal reproduction in a randomly varying environment. Journal of Ecology 56:219228.CrossRefGoogle Scholar
Demel, Teketay. 1992. Human impact on a natural montane forest in south-eastern Ethiopia. Mountain Research and Development 12:393400.Google Scholar
Demel, Teketay. 1993. Problems associated with raising trees from seeds: the Ethiopian experience. Pp. 91100 in Lieth, H. & Lohman, M. (eds). Restoration of tropical forest ecosystems. Kluwer Academic Publishers, Dordrecht. 269 pp.Google Scholar
Demel, Teketay & Granström, A. 1995. Soil seed banks in dry Afromontane forests of Ethiopia. Journal of Vegetation Science 6:777786.Google Scholar
Fenner, M. 1995. Ecology of seed banks. Pp. 507528 in Kigel, J. & Galili, G. (eds). Seed development and germination. Marcel Dekker Inc., New York. 853 pp.Google Scholar
Friis, I. 1992. Forests and forest trees of north-east tropical Africa. Kew Bulletin Additional Series 15:1396.Google Scholar
Foster, S. A. 1986. On the adaptive value of large seeds for tropical moist forest trees: a review and synthesis. Botanical Review 52:260299.CrossRefGoogle Scholar
Garwood, N. C. 1989. Tropical soil seed banks. Pp. 149209 in Leek, M. A., Parker, V. T. & Simpson, R. L. (eds). Ecology of soil seed banks. Academic Press, Inc., San Diego, California. 462 pp.CrossRefGoogle Scholar
Geldenhuys, C. J. 1993. Reproductive biology and population structures of Podocarpus falcatus and P. latifolius in southern Cape forests. Botanical Journal of the Linnean Society 112:5974.CrossRefGoogle Scholar
Hedberg, I. & Edwards, S. (eds). 1989. Flora of Ethiopia, Vol. 3. Addis Ababa University, Addis Ababa, and Uppsala University, Uppsala. 659 pp.Google Scholar
Holthuizen, A. M. A. & Boerboom, J. H. A. 1982. The Cecropia seedbank in the Surinam lowland rain forest. Biotropica 14:6268.CrossRefGoogle Scholar
Hopkins, M. S. & Graham, A. W. 1987. The viability of seeds of rain forest species after experimental soil burials under tropical wet lowland forest in north-eastern Australia. Australian Journal of Ecology 12:97108.CrossRefGoogle Scholar
Jansen, P. C. M. 1981. Spices, condiments and medicinal plants in Ethiopia, their taxonomy and agricultural significance. Centre for Agricultural Publishing and Documentation, Wageningen. 327 pp.Google Scholar
Jones, S. 1989. The influence of stratification, scarification, hot water and maternal plant on the germination of Juniperus excelsa seeds from Eritrea. International Tree Crops Journal 5:221235.CrossRefGoogle Scholar
Kigel, J. 1995. Seed germination in arid and semiarid regions. Pp. 645699 in Kigel, J. & Galili, G. (eds). Seed deveopment and germination. Marcel Dekker, Inc., New York. 853 pp.Google Scholar
Laurent, N. & Chamshama, S. A. O. 1987. Studies on the germination of Etythrina abyssinica and Juniperus procera. International Tree Crops Journal 4:291298.CrossRefGoogle Scholar
Lebrón, M. L. 1979. An autecological study of Palicourea riparia Bentham as related to rain forest disturbance in Puerto Rico. Oecologia (Berlin) 42:3146.CrossRefGoogle ScholarPubMed
Leck, M. A., Parker, V. T. & Simpson, R. L. (eds). 1989. Ecology of soil seed banks. Academic Press, Inc., San Diego, California. 462 pp.Google Scholar
Legesse, Negash. 1992. In vitro methods for the rapid germination of seeds of Podocarpus falcatus. SINET: Ethiopian Journal of Science 15:8597.Google Scholar
Legesse, Negash. 1993. Investigations on the germination behaviour of wild olive seeds and the nursery establishment of the germinants. SINET: Ethiopian Journal of Science 16:7181.Google Scholar
Murdoch, A. J. & Ellis, R. H. 1992. Longevity, viability and dormancy. Pp. 193229 in Fenner, M. (ed.). Seeds: the ecology of regeneration in plant communities. CAB International, Wallingford. 373 pp.Google Scholar
Murray, K. G. 1988. Avian seed dispersal of three neotropical gap-dependent plants. Ecological Monographs 58:271298.CrossRefGoogle Scholar
Negussie, Achalu, Good, J. E. & Mayhead, G. J. 1991. The effects of pretreatments and diurnal temperature variation on the germination of Juniperus excelsa. International Tree Crops Journal 7:5766.CrossRefGoogle Scholar
Ng, F. S. P. 1978. Strategies of establishment in Malayan forest trees. Pp. 129162 in Tomlinson, P. B. & Zimmermann, M. H. (eds). Tropical trees as living systems. Cambridge University Press, London. 675 pp.Google Scholar
Ng, F. S. P. 1980. Germination ecology of Malaysian woody plants. Malaysian Forester 43:406437.Google Scholar
Orozco-Segovia, A. & Vázquez-Yanes, C. 1989. Light effects on seed germination in Piper L. Acta Oecologia/Oecologia Planlarum 10:123146.Google Scholar
Perez-Nasser, N. & Vázquez-Yanes, C. 1986. Longevity of buried seeds from some tropical rain forest trees and shrubs of Veracruz, Mexico. Malaysian Forester 49:352356.Google Scholar
Priestley, D. A. 1986. Seed ageing: implications for seed storage and persistence in the soil. Cornell University Press, Ithaca, New York. 304 pp.Google Scholar
Swaine, M. D. & Whitmore, T. C. 1988. On the definition of ecological species groups in tropical rain forests. Vegetatio 75:8186.CrossRefGoogle Scholar
Silvertown, J. W. 1980. The evolutionary ecology of mast seeding in trees. Biological Journal of the Linnean Society 14:235250.CrossRefGoogle Scholar
Thompson, K. 1992. Functional ecology of soil seed banks. Pp. 231258 in Fenner, M. (ed.). Seeds: the ecology of regeneration in plant communities. CAB International, Wallingford. 373 pp.Google Scholar
Thulin, M. 1989. Fabaceae. Pp. 49251 in Hedberg, I. & Edwards, S. (eds). Flora of Ethiopia, Vol. 3. Addis Ababa University, Addis Ababa, and Uppsala University, Uppsala. 659 pp.Google Scholar
Uhl, C. & Clark, K. 1983. Seed ecology of selected Amazon basin successional species. Botanical Gazette 144:419425.CrossRefGoogle Scholar
Uhlig, S. K. & Uhlig, K. 1990. The floristic composition of a natural montane forest in south-eastern Ethiopia. Feddes Repertorium 101:227234.CrossRefGoogle Scholar
Vázquez-Yanes, C. & Orozco-Segovia, A. 1982a. Germination of seeds of a tropical rain forest shrub, Piper hispidum, Sw. (Piperaceae) under different light qualities. Phyton 42:143149.Google Scholar
Vázquez-Yanes, C. & Orozco-Segovia, A. 1982b. Seed germination of a tropical rain forest pioneer tree (Heliocarpus donnell-smithii) in response to diurnal fluctuation of temperature. Physiologia Plantarum 56:295298.CrossRefGoogle Scholar
Vázquez-Yanes, C. & Orozco-Segovia, A. 1993. Patterns of seed longevity and germination in the tropical rain forest. Annual Review of Ecology and Systematics 24:6987.CrossRefGoogle Scholar
Vázquez-Yanes, C. & Orozco-Segovia, A. 1994. Signals for seeds to sense and respond to gaps. Pp. 209236 in Caldwell, M. M. & Pearcy, R. W. (eds). Exploitation of environmental heterogeneity by plants: ecophysiologcal processes above and below ground. Academic Press, Inc., New York. 429 pp.CrossRefGoogle Scholar
Vázquez-Yanes, C. & Smith, H. 1982. Phytochrome control of seed germination in the tropical rain forest pioneer tree Cecropia obtusifolia and Piper auritum and its ecological significance. New Phytologist 92:477485.CrossRefGoogle Scholar
Venable, D. L. & Brown, J. S. 1988. The selective interactions of dispersal, dormancy, and seed size as adaptations for reducing risk in variable environments. American Naturalist 131:360384.CrossRefGoogle Scholar
Viana, V. 1990. Seed and seedling availability as a basis for management of natural forest regeneration. Pp. 99115 in Anderson, A. B. (ed.). Alternatives to deforestation: steps towards sustainable use of the Amazon rain forest. Columbia University Press, New York. 281 pp.Google Scholar
Whitmore, T. C. 1983. Secondary succession from seed in tropical rain forests. Forestry Abstracts 44:767779.Google Scholar
Whitmore, T. C. 1991. An introduction to tropical rain forests. Oxford University Press, Oxford. 226pp.Google Scholar
Zar, J. H. 1984. Biostatistical analysis. Prentice-Hall, Englewood Cliffs, New Jersey. 718 pp.Google Scholar