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LOURENS RIVER ESTUARY: Ecology
  Flora
Phytoplankton/Diatoms
A phytoplankton and diatom survey in 1982 revealed that there were various planktonic and epiphytic pinnate diatoms along with colonial green algae, such as Scenedesmus sp. and Coelastrum sp. (Ref. 2).
During a survey in the summer (December to March) of 1982, dense algal mats occurred on the surface and the bed of the estuary.  These were identified as Cladophora sp., Enteromorpha sp., E. plumose and Chaetomorpha sp. The algal mats became less in April and in May they only occurred in isolated patches (Ref 2).
Algae
In 1982, no attached marine algae were found on the adjacent sandy beach.(Ref 2).
Aquatic Vegetation
 
Semi-aquatic Vegetation
In 1982, semi-aquatic vegetation comprised Juncus kraussi, Phragmites australis, Typha capensis, Cyperus textiles, Paspalum vaginatum and Scorpus nodosus.(Ref 2).
No salt marsh vegetation occurred along the estuary (Ref 2).
Terrestrial vegetation
In 1982 the terrestrial vegetation comprises:
Sparse covering of “pypgras” (Ehrharta villosa), “strandblommetjies” (Senecio elegans) and Trachyandra divaricata occurred in 1982 in the Fore Dune Area (Ref. 2).
A Disturbed Dune Vegetation area occurred in 1982 around the overflow pond, containing numerous dune plants, such as “kinkelbossie” (Tetragonia fructicosa), Carpobrotus edulis, “bergtee” (Geranium incanum) and Pelargonium capitatum.  This area was however, disturbed by kikuyu (Pennisetum clandestinum). Acacia saligna and A. Cyclops have been cleared, but young plants had already reappeared (Ref. 2).
To the west of the overflowing pond was an extensive Typha capensis swampland (Ref. 2).  These swamps are considered to be important in filtering excessive nutrients from the overflowing pond, before it enters the sea.
Immediately inland of the beach road is a weed area, where cover is sparse and a variety of weed, such as Conyza cf ambiqua, Sonchus oleraceus occurred in 1982 (Ref. 2).
Fauna
Zooplankton
In a zooplankton sample taken during a survey in 1982 the families Protozoa, Rotifera, Copepoda, Cirripedia and Osteichthyes (in the form of fish eggs) were represented, but most abundant, were the harpacticoid copepods, the copepods Acartia longipatella and the rotifers.(Ref. 2).
Aquatic Invertebrates

Aquatic invertebrates identified from trawls in the estuary, were midge larvae (Chiromidae).  No prawn holes were observed.(Ref. 2).
Insects
 
Fish
After the spillage of raw sewage in 1982 into the estuary, a large amount of fish died, among them were white steenbras (Lithognathus lithognathus), harder (Liza richardsoni), sea barbel (Arius feliceps), leervis (Lichia amia) and elf (Pomatomus saltator).(Ref. 2).
Amphibians and Reptiles
As far as reptiles and amphibians were concerned, twelve frog species, of which the Cape Rain Frog (Breviceps gibbosus) is endangered; eleven snake species; eight lizards species, of which the Cape Dwarf Chameleon (Bradypodion pumilum) is endangered, and four tortoise species, of which the Geometric Tortoise (Psammobotes geometricus) is endangered, were recorded during a survey in 1982 (Ref. 2).
Birds
In 1981, a total number of 32 different bird species were recorded at the Lourens Estuary, of which the Common Tern, the Arctic Tern and the Red Cormorant were the most abundant (Ref. 5).
Mammals
Mammals, such as the Cape clawless otter (Aonyx capensis), the Cape dune mole-rat (Bathyergus sucillus), the water mongoose (Atilax paludinosis), Steenbok (Raphicerus campestris) and Grysbok (Raphicerus melanotis) were observed near the Lourens Estuary between 1976 (Ref. 6) and 1980 (Ref. 7).

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