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Adaptive strategies of African pteridophytes to extreme environments

Published online by Cambridge University Press:  05 December 2011

Jan Kornás
Jan Kornás
Affiliation:
Institute of Botany, Jagiellonian University, ul. Lubicz 46, 31–512 Kraków, Poland
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Synopsis

Water deficiency is the key factor limiting the occurrence of pteridophytes in seasonally dry tropical areas and shaping their adaptive strategies in respect of habitat preferences, life-forms, phenological patterns, and reproductive biology. In Zambia, which is situated in the savanna woodland zone, a total of 146 pteridophyte species occur mainly in special habitats: extrazonal evergreen forest patches and initial successional stages of lithoseres and hydroseres. Life-forms with perennating buds well protected against desiccation (hemicryptophytes and geophytes) dominate, while those with more exposed buds (epiphytes, chamaephytes and phanerophytes) are much less numerous and restricted mainly to the higher-rainfall areas. Selaginella tenerrima represents the life form of a therophyte, unknown in any other pteridophyte genus. Three major seasonal patterns of growth and dormancy may be distinguished: the evergreen type (ca. 40% of species), the poikilohydrous type (ca. 20%) and the deciduous (‘summer-green’) type (ca. 40%). No less than 20% of species are able to survive recurrent bush-fires, and some of them possess the features of advanced pyrophytes. In the driest parts of the savanna zone in Africa, e.g. in the Lake Chad Basin of northeastern Nigeria, seasonal pools are remarkably rich in water ferns, especially of the genus Marsilea which has undergone an intensive adaptive radiation in this environment.

Type
Research Article
Information
Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences , Volume 86: The Biology of Pteridophytes , 1985 , pp. 391 - 396
Copyright
Copyright © Royal Society of Edinburgh 1985

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References

Gams, H. 1938. Ökologie der extratropischen Pteridophyten. In Manual of Pteridology, ed. Verdoorn, F., pp. 382–419. The Hague: M. Nijhoff.CrossRefGoogle Scholar
Holttum, R. E. 1938. The ecology of tropical pteridophytes. In Manual of Pteridology, ed. Verdoorn, F., pp. 420–450. The Hague: M. Nijhoff.CrossRefGoogle Scholar
Kornaś, J. 1975. Tuber production and fire-resistance in Lycopodium carolinianum L. in Zambia. Acta Soc. Bot. Pol. 44, 653–663.CrossRefGoogle Scholar
Kornaś, J. 1978a. Fire-resistance in the pteridophytes in Zambia. Fern Gaz. 11, 6, 373–384.Google Scholar
Kornaś, J. 1978b. Life-forms and seasonal patterns in the pteridophytes in Zambia. Acta Soc. Bot. Pol. 46, 669–690.CrossRefGoogle Scholar
Kornaś, J. 1979. Distribution and ecology of the pteridophytes in Zambia, pp. 1–207. Warszawa-Kraków: PWN.Google Scholar
Kornaś, J. 1983. Pteridophyta collected in Northern Nigeria and Northern Cameroon. Acta Soc. Bot. Pol. 52, 3–4, 321–334.CrossRefGoogle Scholar
Kornaś, J. and Jankun, A. 1983. Annual habit and apomixis as drought adaptations in Selaginella tenerrima. Bothalia 14, 3–4, 647–651.CrossRefGoogle Scholar
Launert, E. 1968. A monographic survey of the genus Marsillea Linnaeus. I. The species of Africa and Madagascar. Senckenbergiana Biol. 49, 273–315.Google Scholar
Page, C. N. 1979. The diversity of ferns. An ecological perspective, in The Experimental Botany of Ferns, ed. Dyer, A. F., pp. 9–56. London: Academic Press.Google Scholar
Raunkiaer, C. 1905. Types biologiques pour la géographie botanique. Overs. Danske Vidensk. Selsk. Forh. 1905, 5, 347–437.Google Scholar
Schelpe, E. A. C. L. E. 1970. Flora Zambesiaca. Pteridophyta, pp. 1–254. London: Crown Agents for Oversea Governments and Administrations.Google Scholar