The biogeography and biodiversity of the Namibian intertidal seaweed flora

There have been very few intertidal studies carried out on the Namibian coast. With respect to seaweeds in particular there have been a number of species lists and shore descriptions, but very little research into the biogeography, diversity or ecology. One of the reasons for the lack of research is probably that much of the 1500 km coast is inaccessible. The coastline is relatively straight with few inlets or bays and comprises mostly sandy beaches, with few rocky shores. Estimates range from 5-16% of rocky shores for the total coast length, and as a result there is relatively little substrate on which seaweed can attach. The dominant current is the northward, slow-flowing Benguela current. Upwelling also occurs here due to long shore winds, which bring cool, nutrient-rich water to the surface. In this study the Namibian coast was divided into three regions, largely governed by accessibility to the coast, viz. southern, central and northern Namibian. Most of the Namibian coast is subject to severe wave action, as a result wave-exposed shores were predominantly chosen. The degree of wave exposure was determined by the degree to which the site was open to the ocean. Sites that were completely or largely protected from incoming swells were not included. Three sites in the southern region were semi-exposed, in that they occurred within relatively large bays and were partially protected from dominant winds, they were however relatively exposed to the open ocean. Two to three transects lines were taken on each shore, along which quadrats were sampled at regular intervals. The material was taken back to the laboratory, sorted and analysed. Multivariate techniques were used as diagnostic tools in the interpretation of the data. Detailed seaweed species data were collected from all samples (biomass of individual species as well as general species collections), while data on major sessile invertebrate groups and amount of sand were also collated.

Grantor dc:publisher.institution

Department of Biological Sciences

Year dc:date.issued

1998

Author dc:creator

• Engledow, Henry Riley

Advisor dc:contributor.advisor

• Bolton, John J

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/9066

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/9066