Relationships between soil seed banks and above-ground vegetation along a disturbance gradient in the W National Park trans-boundary biosphere reserve, West Africa

Savadogo, P and Sanou, L and Dayamba, S D and Bognounou, F and Thiombiano, A (2017) Relationships between soil seed banks and above-ground vegetation along a disturbance gradient in the W National Park trans-boundary biosphere reserve, West Africa. Journal of Plant Ecology, 10 (2). pp. 349-363. ISSN 1752-9921

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Abstract

Aims Vegetation succession depends on the availability of suitable propagules in the soils, thus knowledge of soil seed banks is essential for formulating effective strategies for restoring the vegetation of degraded sites. The W National Park, the only trans-boundary biosphere reserve in West Africa, is being extensively fragmented and degraded in recent decades. The aims of this study were to assess the reserve’s soil seed banks, their relationships with standing vegetation and bundle of disturbances and their potential significance for vegetation restoration. Methods The size and composition of the above-ground species vegetation were assessed in nine plots of 1 ha each representing a range of habitats with differing disturbance severity (low, intermediate and high). A total of 702 soil samples were taken from three layers (0–3, 3–6 and 6–9cm) and soil seed bank was analyzed using the seedling emergence technique. Important Findings Generally, seeds of non-woody taxa dominated in samples from all soil depths and habitats of all disturbance severities. The mean soil seed density was 17.8, 24.4 and 26.3 seeds/dm3 in samples from the least, intermediate and most disturbed sites, respectively, and highest in the upper soil layers in all cases. The results indicate that there is limited potential for restoring woody vegetation solely from soil seed banks, and that woody species in the region rely more on recently shed seeds trapped in the standing dead biomass and litter on the ground than soil seed banks for regeneration. Thus, human intervention is needed to accelerate forest recovery, mainly through alleviating anthropogenic impacts on the ecosystem (for instance, avoiding destruction of new seeds by intense fire), and site manipulation to improve environmental conditions for seedling establishment and growth. Other ways of restoring forests than through the soil seed bank (e.g. sowing seeds collected elsewhere, and planting tree seedlings) could also be relevant.

Item Type: Article
Divisions: Research Program : West & Central Africa
CRP: UNSPECIFIED
Uncontrolled Keywords: Disturbance, Savanna–woodland restoration, Regeneration, Seed bank, Vegetation degradation, West Africa, Soil seed bank, Vegetation
Subjects: Others > Soil
Others > Soil Science
Others > African Agriculture
Others > West Africa
Depositing User: Mr Ramesh K
Date Deposited: 21 Jul 2017 05:03
Last Modified: 29 Dec 2017 09:54
URI: http://oar.icrisat.org/id/eprint/10098
Official URL: http://dx.doi.org/10.1093/jpe/rtw025
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: We thank the management team of the W National Park and the Institute of Environment and Agricultural Research for the support they offered during the field work. This work would not have been done without funding from Volkswagen Foundation’s funding initiative ‘Knowledge for Tomorrow—Cooperative Research Projects in Sub-Saharan Africa’ for the first author. Thanks are also due to CGIAR Research Program on Dry lands (CRP 1.1) for support. The authors are also grateful to anonymous reviewers who made significant suggestions for improving this article. We are grateful to Dr John Blackwell and Sees–editing Ltd for linguistic improvements.
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