Aims Vegetation succession depends on the availability of suitable prop-agules in the soils,thus knowledge of soil seed banks is essential for formulating effective strategies for restoring the vegetation of degraded ...Aims Vegetation succession depends on the availability of suitable prop-agules 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 bio-sphere 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 veg-etation 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 6-9 cm)and soil seed bank was analyzed using the seed-ling 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/dm^(3) in samples from the least,intermediate and most disturbed sites,respectively,and highest in the upper soil layers in all cases.The results indi-cate 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 regen-eration.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 environmen-tal 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.展开更多
文摘Aims Vegetation succession depends on the availability of suitable prop-agules 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 bio-sphere 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 veg-etation 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 6-9 cm)and soil seed bank was analyzed using the seed-ling 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/dm^(3) in samples from the least,intermediate and most disturbed sites,respectively,and highest in the upper soil layers in all cases.The results indi-cate 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 regen-eration.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 environmen-tal 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.
