Vegetation succession and soil properties following the removal of pine plantations on the eastern shores of Lake St Lucia, South Africa.
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Date
1998
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Abstract
Pine plantations have been established on secondary grassland on the dune systems of the
Eastern Shores of Lake St Lucia, KwaZulu-Natal, South Africa for the past 40 years. These
plantations have been progressively felled for the past six years, and will continue to be felled
until the year 2011, by which time they will be eliminated.
Space-for-time substitution was used to determine the direction of both woody and herbaceous
vegetation succession and to predict possible future management implications for the Eastern
Shores. Soil samples were taken from undisturbed grassland, grassland with trees, dune forest,
pine plantations, and clearfelled areas at various successional stages. To determine the effects
of the pine plantations on the soils of the area, soils were subjected to particle size analysis,
and determination of pH, organic carbon, phosphorus, exchangeable bases, iron and
aluminium.
Minimal modification of the sandy soils by the pine plantations was found to have occurred.
That which did occur was shown to be short-term, and to be ameliorated by the establishment
of an indigenous woody understorey, resembling pioneer dune forest. Soil under plantations
was shown to have a lower pH and cation exchange capacity than under opposite indigenous
vegetation but no other direct effects were observed. The direction of succession was
determined by the nature of the indigenous vegetation adjacent to the plantation. Pine
plantations were shown to facilitate succession towards dune forest by the exclusion of fire,
provision of perches and refugia for forest-dwelling animals, and creation of a forest
environment for the establishment of trees. However, the extent of re-establishment of
indigenous dune forest under pine plantations was shown to be directly related to the nature
of the adjacent indigenous vegetation, be it grassland, grassland with trees or dune forest.
Description
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.
Keywords
Forests and forestry--Environmental aspects--KwaZulu-Natal--Saint Lucia, Lake., Land use--Environmental aspects--KwaZulu-Natal--Saint Lucia, Lake., Sand dune plants--KwaZulu-Natal--Saint Lucia, Lake., Vegetation surveys--KwaZulu-Natal--Saint Lucia, Lake., Theses--Grassland science.