The ecology and plant functional composition of the afromontane palustrine wetlands in Lesotho
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Date
2020-02
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National University of Lesotho
Abstract
The classification and description of wetland vegetation is important for biodiversity conservation and
water resource management as it provides an understanding of the wetland vegetation-environment
relationships and information to interpret spatial variation in plant communities. This study
characterises the Afromontane palustrine wetlands of Lesotho in terms of plant communities, plant
functional types and plant functional composition. Relationships of plant communities and functional
traits were also explored. Vegetation, environmental and plant functional trait data were collected using
the Braun-Blanquet method and standard methods. The data were analysed mainly by means of
clustering, ordination and diversity analysis techniques. Twenty-two communities were produced by
the classification of the Afromontane wetland vegetation and seven plant functional types, as well as
seven functional communities were obtained from the classification. The wetland plant communities
are diverse in terms of species richness. The ordination revealed that the wetland vegetation is mainly
influenced by altitude, longitude, slope, soil parent material, landscape, inundation, peat, potassium
content, soil texture, total organic carbon, nitrogen, sulphur, electrical conductivity, calcium, soil depth,
wetness, magnesium, aspect and latitude. Plant functional traits and functional composition of the
communities were found to be broadly influenced by altitude, slope, longitude, soil parent material,
landscape and inundation, and more finely by edaphic factors that include electrical conductivity,
calcium, sodium, magnesium, nitrogen, organic matter, total organic carbon, clay percentage, pH, sand
percentage and potassium. Regarding species composition and diversity, plant communities in the
Highlands were more diverse and were distinctively different from those in the Lowlands. Although a
few wetlands, particularly in the Highlands are still in their near-pristine condition, many wetlands in
the country are showing severe signs of degradation. While some communities are either restricted to
the Highlands or Lowlands, others exhibit a wide ecological amplitude and occur in both regions. The
study further highlights the possibility of alterations in plant functional traits, types and functional
composition in the face of environmental changes, including climate change. The diversity of most of
the wetlands, coupled with their restricted habitat and distribution at high altitudes and their role in
supplying ecosystem services that include water resources, highlights the high conservation value
associated with these wetlands, particularly in the face of climate change and loss of biodiversity.
Description
Keywords
Afromontane palustrine wetland, Biodiversity, Community-weighted mean, Conservation, Ecosystem function, Functional composition, Maloti-Drakensberg, Plant community, Plant functional type, Plant functional trait, Vegetation classification