Vegetation structure,dominance patterns and height growth in an Afromontane forest,Southern Africa

Information on forest structure is fundamentally important to track successional vegetation dynamics for efficient forest management.This study reports on vegetation characteristics,dominance patterns and species height growth in a northern mistbelt forest type in South Africa.Common alpha-diversity indices(species richness and Shannon-Weiner diversity),structural vegetation parameters(tree density and basal area),and species importance value index were used.Size class distribution and height-diameter allometry were further examined for the overall stand and most important species.Stem densities(472.0±43.5 and 605.3±28.1 trees ha^-1 for C 5 cm to\10 cm and C 10 cm dbh(diameter at breast height)classes,respectively)and basal area values(1.99±0.19 and 48.07±3.46 m^2 ha^-1,respectively)are comparable to other Afromontane forests in East Africa.The overall stand showed an inverted-J shaped distribution pattern which is a typical feature of stand size class distribution in most natural forests.Most ecologically important species also exhibited an inverted-J shaped distribution pattern,suggesting good regeneration and recruitment potential.There were significant differences in species on height,reflecting species-specific height growth patterns,possibly a result of intrinsic growth potential and competitive interactions.The present study suggests that conservation and management policies,including protection of surrounding land uses against fire,contribute to maintaining a successful recovery of these forests.However,it should be noted that these forests may be experiencing relatively slow dynamic flux as a result of the overmature state of some trees with several years under relatively strict protection.

Modeling vulnerability of protected areas to invasion by Chromolaena odorata under current and future climates

Invasive plant species and climate change are among the biggest threats to the ecological integrity of many ecosystems,including those of protected areas.Effective management of invasive plants requires information regarding their spatialdistributions Using maximum entropy,wemodeled habitat suitability for an invasive plant species Chromolaena odorata under current and future climatic conditions(HadGEM2-ESand MIROC5)in protected areas of four West African countries(Benin,Cote d'voire,Ghana,and Togo).Under current climatic conditions,approximately 73%of total land area within the protected areas was suitable for colonization by C.odorata.Under future climate projections,the total area of suitable habitats for this invasive plant was projected to decrease by 7-9%(HadGEM2-ES)and 12-14%(MIROC5).Country-specific patterns suggest that major protected areas in Cote d'Ivoire and Ghana will be more vulnerable to invasion by C.odorata than those in Benin and Togo under both current and future dimatic scenarios.To maintain normal ecosystem functioning and provisioning of ecosystem services within the protected areas studied here,locations that have been identified as most vulnerable to invasion by C.odorata should be accorded proportionately higher priority when formulating appropriate management strategies.