The floristic composition of a natural montane forest in Southeast Ethiopia

Granström

1995

J Vegetation Science

118

Abstract. The soil seed bank was investigated in four dry Afromontane forests of Ethiopia. At least 167 plant species were identified in the 0–9 cm soil layer with total densities ranging between 12 300 and 24 000 seeds/m2. Herbs were represented with the largest numbers of species and seeds in the seed bank, while the contribution of tree species was generally low. The overall vertical distribution of seeds was similar at all sites with the highest densities occurring in the upper three cm of soil and gradually decreasing densities with increasing depth. Relatively high densities also occurred in the litter layer. There were large differences in depth distribution between species, suggesting differences in seed longevity. A large number of species in dry Afromontane forests evidently store quantities of seeds in the soil and this is in contrast to the situation in most tropical rain forests, dry lowland forests and savannas, where both the number of seeds and the number of species are relatively small. It is possible that the strongly seasonal and unpredictable climate of this region may have selected for high levels of dormancy, and that herb regeneration is associated with small scale disturbance. The fact that most of the dominant tree species do not accumulate seeds in the soil suggests that their regeneration from seed would be unlikely if mature individuals disappeared. Most tree species have relatively large seeds and poor long‐distance dispersal; this implies that restoration of Afromontane forests after destruction would be difficult. Since there is a diverse seed bank of the ground flora, this component of the vegetation would have a better chance of reestablishing. However, because most cleared forest land is used for agricultural crop production, it is probable that the seed bank will be depleted in only a few years. Therefore, the future of the Afromontane forest flora seems to depend on the successful conservation of the few fragments of remaining natural forest.

Section: Discussionmentioning

confidence: 48%

Section: Gara Adesmentioning

confidence: 99%

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Soil seed banks in dry Afromontane forests of Ethiopia

Granström

1995

J Vegetation Science

118

“…The area contains volcanic bedrocks and deep and dark grey loam soils with relatively high content of organic matter. At the summit and on ridges the soil is shallow and the rocks are exposed in some place\ (MURPHY 1968;UHLIG & UHLIG 1990). The study site ranges between 2100 m and 2775 m and receives a mean annual rainfall of about 1200 mm with the highest rainfall extending between June and September; a less pronounced wet period occurs in March and April (ANONYMOUS 1988).…”

Section: Study Sitementioning

confidence: 99%

Soil seed bank at an abandoned Afromontane arable site

1998

Feddes Repertorium

Soil seed bank at an abandoned Afromontane arable site With 5 Figures and 2 TablesS u m m a r y Species diversity, density and spatial distribution of the soil seed bank was investigated at an Afromontane forest site abandoned after clearing and cultivation in eastern Ethiopia. At least 89 plant species were identified in the litter and soil layers down to 9 c m with a total mean density of 11870 viable seeds/m2 (standard error = 3674 seeddrn'). Herbs accounted for 89% of the species and 93% of the total soil seed bank. The share of woody species in the soil seed bank was very low, probably due to the continuous weeding associated with cultivation of crops at the site. Most of the species represented in the soil seed bank are successional species with hard seeds that can withstand and regenerate after disturbances. There were large differences in the spatial distribution between species, suggesting differences in mode of dispersal, seed longevity and predation pressure. Out of the 89 species, 46 species were recorded from only one sample, 41 species from two to nine samples and only two species from all the ten samples. The density of seeds recovered from the ten samples ranged between 2090 and 37 070 seeds/m'. The overall vertical distribution showed a similar I I Feddes Repert. 109 (1998) I -2

“…It shows significant contrast in structure when compared to other coniferous forests of the central plateau (TAMRAT BEKELE 1994). The importance of natural forests in such ecosystems as in Ethiopia should not be overemphasized (FRIIS et al 1982;HURNI 1986;HILLMAN 1986HILLMAN , 1988SEBSEBE DEMISSEW 1988;UHLIG 1988UHLIG . 1990aDEMEL TEKETAY 1992).…”

Section: Introductionmentioning

confidence: 99%

Floristic composition of Wof‐Washa natural forest, Central Ethiopia: Implications for the conservation of biodiversity

Bekele

1995

Feddes Repertorium

Wof‐Washa forest is one of the very few remaining natural forests in Ethiopia. It is the only stretch of forest left in the surrounding. The main reason for its survival is its inaccessibility. The local people use the forest as a source of fuelwood, construction material, farm implements, edible fruits, honey, medicinal plants, water and game for hunting. As one of the major activities of the local people is livestock production, it provides grazing areas. Since the forest has not been commercially exploited, it is a potential source of merchantable forest products. It also provides food, shelter and breeding areas for many wild animals. The forest prevents soil erosion and regulates the watershed in the surrounding. However, the threat to its destruction is becoming apparent because of encroaching agriculture, cutting of trees by the local people, fire and overgrazing. Studies on the floristic composition of the forest were made in 1992 to lay the foundation on which recommendations for future conservation of biodiversity and development of the forest can be made. The studies revealed that there are over 252 species of plants: 33 (13%) trees, 18 (7%) shrubs and 201 (80%) herbs. Among these, 29 species (12%) are endemic to Ethiopia while 7 (3%) are nearly endemic. The floristic composition of the forest is compared with other forests both inside and outside Ethiopia. The most similar forests analysed have only about 54% species in common with Wof‐Washa forest. The forest is endowed with a remarkable number of common, rare and endemic plant species and wild animals. Many of the species are habitat specific and can only be found in limited areas in the forest. Their survival depends upon the existence of the forest. Any kind of man‐made disturbance which does not take into account this reality is very likely to destroy the specific habitats of the species and to upset the natural processes which will in turn result in local extinction of both plant and animal species. Moreover, it will reduce the amount of available water in the lowlands and accelerate soil erosion on the highlands. Based on the results of the present study. it is recommended that the forest be converted into a National Nature Reserve.