 |
Environment and development in coastal regions and in small islands |
 |
|
Environment and development in coastal regions and in small islands |
|
 |
Progress
report
|
Land-Ocean
Interactions |
Monitoring
the coastal zone of tropical southeast Africa for eco-tourism attributes and
environmental influences on biodiversity
M. R. Jury with Y. Govender, A. Mthembu, S. Guyot, J. Mitchell and G. Mulder
Centre for Environmental Studies, University of Zululand
The Maputaland coast of northeastern South Africa (27°20’S) is the site for repeated analysis of environmental factors maintaining coastal biodiversity. The physical setting of high sand dunes covered by dense forests edged by coral reefs, interspersed by inland lakes and grasslands and sparse human settlements is unique. Ecological conservation, limited coastal development and local communities compete for natural resources. This progress report covers two surveys in March 2001 (Mabibi) and June 2001 (Kosi Bay - Ponto), primarily aimed at assessing how development strategies will impact ecology and human use.
The March 2001 survey was again based at Mabibi camp, and underpinned Ms Govender’s MSc thesis and sought to wrap up any loose ends in the previous research. To place the current survey into historical context, a climate analysis is performed. The temperature, precipitation and wind speed patterns over the Maputaland coast averaged for November 1960-2000 exhibit interesting contrasts. Temperatures increase toward the north and reach a maximum at the junction of the three countries (Mozambique, South Africa and Swaziland). Precipitation is low in the north and increases toward Richards Bay. Wind speeds are strongest in the south and decrease northward and inland as expected. Swells, analysed from ship data in the period 1960-2000, are mainly southerly during winter, but exhibit a northeasterly component in summer. Hence longshore drift within the surf zone is weakest in summer. The results suggest that Mabibi has a moderate tropical climate with ‘in-between’ values for temperature, precipitation and wind speed.
Following our most recent field survey in April 2000 reported in the previous progress report, this field survey conducted from 27 November to 3 December 2000 had more specific objectives. The prescribed east - west transect (on 27°20’S) was sampled for zoological diversity and environmental conditions; from the beach south of Mabibi inland to the Lake (figure 1). The surveys were designed to identify contrasts from beach-to-forest-to-savanna and were conducted by five staff members of the Centre for Environmental Studies, University of Zululand. Each morning two teams set out to make the marine (drifter, sand), physical (climate, soils, etc.), zoological (insect, etc) and demographic (questionnaires) observations. Zoological sampling was accomplished at five points along the transect (one each day) covering the prescribed 10 m2 quadrat, noting the location using a Global Positioning System. At each quadrat animal species were identified, described and counted, and selected specimens were collected. Climate data were collected twice daily at sampling points including temperature and humidity, wind speed and direction, and weather / sea conditions. Sea spray samples were taken along the foredune. Soil samples were collected along a ‘replicate’ transect about 1 km to the north of the original one, for comparative purposes. On the beach and foredune, sand height profiles were measured using a theodolite and staff. Ocean drifters were deployed from the point at Mabibi and tracked using double theodolite trigonometry. Demographic data were collected by visiting the local population, and by interviewing tourists on the beach. A rural prosperity index was formulated to place the demographic results into an objective framework. The final results will be written up in the thesis of Govender (MSc), and preliminary results are given below.
|
| Figure 1 – Aerial photo of the Mabibi ecological transect |
Zoological data collection for November 2000 surveys
The techniques for estimating the abundance and distribution of species of plants along a transect are difficult to use for animals, since many are hidden or difficult to locate, whilst those that are visible are often highly mobile. Plots were selected within each plant community type and sampled for: earthworms, insects, frogs, small mammals and large mammals. Due to time constraints, detailed survey work concentrated on trapping insects, and visual and auditory monitoring of birds, amphibians, reptiles and mammals.
Two malaise traps were randomly set up within each of the five main plant communities found along the east-west transect to collect flying insects. Six pan traps were set around each of the five quadrats to collect crawling insects. Two butterfly bait traps were set up at each of the five quadrats. The presence of lizards, frogs and snakes was recorded for each plot. Birds were observed visually and bird calls were identified at each quadrat.
Ideally, to get an overview of small mammals occurring within the area Sherman traps or mark-recapture methods should be employed. However due to the lack of equipment, manpower and time constrains, the observational method was used to determine the presence of small mammals. Members of the local community were interviewed on the types of small mammals they catch and utilise for food. All sightings of large mammals occurring in the area were recorded. Information about large mammals was gathered by questioning members of the local community.
Data on humidity, soil temperature and air temperature were recorded hourly, whilst on station at each of the five quadrats. A replicate of soil samples at 20 cm and 1 m depth was taken about 1 km to the north of Hulley Point, along the beach access road. Sea spray was collected on transparencies at various points on the path down to the beach, on the foredune below Mabibi campsite. Climate surveys were conducted twice daily to analyse local changes in humidity, temperature and wind speed.
