Browsing by Author "Brown, Catherine"

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    Biomass partitioning in an endemic southern African salt marsh species Salicornia tegetaria (Chenopodiaceae)
    (Taylor and Francis Group, 2020) Brown, Catherine; Rajkaran, Anusha
    The below ground biomass of salt marsh species accounts for more than half of the total plant biomass in salt marsh systems, yet no biomass data exist for salt marsh species in South Africa. The aims of the current study were to compare the biomass allocation of Salicornia tegetaria in six estuaries and relate findings to their environmental conditions. The current study measured the physico-chemical variables of the sediment (moisture content, organic matter content, electrical conductivity, pH) and pore water (temperature, salinity, pH, depth) at Olifants, Berg, Langebaan, Heuningnes, Nahoon and Kwelerha estuaries. Above and below ground biomass and stem height measurements were also collected. The below ground biomass (1.51 ± 0.24 kg m−2) and root/shoot ratio (1.36 ± 0.17) was the lowest at Heuningnes Estuary with no significant difference at the remaining estuaries, suggesting that factors, such as geomorphology and sedimentological processes, could have a stronger effect on the biomass allocation in this species. Important drivers of biomass allocation were sediment pH, redox potential and pore water depth. The current study provides baseline information for S. tegetaria, an endemic salt marsh species, for which there is a paucity of data. This species plays a major role in the ecology of the lower intertidal zone, which will be vulnerable to sea-level rise.
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    The phylogeography, biomass allocation and phenology of Salicornia tegetaria (S. Steffen, Mucina & G. Kadereit) Piirainen & G. Kadereit, an endemic salt marsh species in South Africa
    (University of the Western Cape, 2018) Brown, Catherine; Rajkaran, A.
    Salicornia tegetaria is an endemic salt marsh macrophyte that is widely distributed in estuaries along the South African coast. The aims of the study were to understand the phylogeography of the species, compare the biomass allocation in two regions and to determine phenological patterns of S. tegetaria between the warm and cool temperate biogeographical regions. The phylogeography of S. tegetaria was studied using the noncoding chloroplast DNA region rpS16 and nuclear rDNA ITS region. Five samples each were collected from eighteen estuaries stretching from Orange River in the Northern Cape to Mngazana Estuary in the Eastern Cape. Above- and belowground biomass was collected and physico-chemical conditions measured at Olifants, Berg and Langebaan Estuaries in the cool temperate, and Heuningnes, Nahoon and Kwelera Estuaries in the warm temperate biogeographical regions. The growth and flowering phenology of S. tegetaria in relation to environmental conditions was investigated in the cool temperate Langebaan Estuarine Embayment and compared to findings in the warm temperate, permanently open Kowie Estuary. The physico-chemical gradient found between the cool and warm temperate biogeographical regions may be useful to study climate change effects on plant species. The comparison of similar habitats in each region may provide insight into how different climate regimes may affect biomass allocation and phenology.