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Staff involved:

Alasdair Edwards, Edmund Green, Peter Mumby, Chris Clark (Sheffield)

Funding:

Department for International Development (DFID)

Compact Airborne Spectrographic Imager (CASI) image of seagrass and reef habitats off the shore of South Caicos. The small island at the south is Dove Cay. The very high resolution (1 m pixels) permits 'blow outs' in the seagrass meadows and large Montastraea colonies to be detected. The image is a colour composite using two blue and one green waveband and has been decorrelation stretched to maximise colour separability.

Regression of the logarithm of seagrass standing crop (g/m²) on processed CASI data (depth-invariant bottom-index generated from bands 3 and 5) showing upper (squares) and lower (triangles) confidence limits. Band 3 was set to 531.1-543.5 nm and band 5 to 630.7-643.2 nm.

Evaluation of the uses and cost-effectiveness of remote sensing for coastal resources assessment and mapping

Project

This project was funded by the UK Department for International Development (formerly ODA) for three years from September 1994. The research evaluated a range of satellite and airborne remote sensing technologies with respect to their abilities (measured in terms of accuracy of outputs) to achieve a suite of defined coastal resource management objectives. This technical evaluation was undertaken in parallel with an economic evaluation of the capital investment, operational, institutional, human resource development and training costs of applying the technologies effectively. Fieldwork was conducted in the Turks & Caicos Islands in collaboration with the TCI Ministry of Natural Resources and in Belize with the collaboration of the Belizean Coastal Zone Management Unit and Coral Cay Conservation Ltd.

The results were published as a series of 11 papers in international scientific journals, three papers in conference proceedings and two articles in remote sensing and GIS technical magazines. They are summarised in a 316 page practical manual Remote Sensing Handbook for Tropical Coastal Management targetted at resource managers, environment departments, coastal zone planners, coastal wetland and marine park managers, and environmental consultancies and NGOs working in developing nations. This was published by UNESCO in early 2000. Training materials were also produced for UNESCO's Bilko remote sensing distance-learning package to accompany the handbook. These are available on CD-ROM with an accompanying 185 page booklet (Applications of Satellite and Airborne Image Data to Coastal Management) published as volume 4 in the Coastal Region and Small Island Papers series of UNESCO in 1999 (reprinted twice). A revised and expanded version was published in 2005 in the same series (Volume 18).

Significance

The coastal environment and its resources are under strong pressure from population growth, industrialisation and tourism throughout the developing world. Integrated management is widely recognised as the basis for sustainable use. The first step towards this generally involves an evaluation and mapping of the resources using remote sensing techniques ranging from aerial photography to satellite imagery. These technologies are potentially a great boon to developing nations wishing to improve management of coastal resources. However, despite their increasing use, there was, until this project, no rigorous analysis of the relative costs and benefits of using different types of satellite and airborne imagery. Furthermore it was unclear which coastal management objectives could practically be achieved using a given technology with a given level of inputs (e.g. ground-truthing, image processing).

Future directions

Following the project it is now possible for planners, consultants and decision makers working in developing nations to decide:

  • when use of remote sensing technologies is likely to be appropriate and cost-effective, and, if they are to be used,
  • what type of imagery will be appropriate for different objectives,
  • the probability of it being already available in archive or acquirable within a project timeframe, and
  • the costs involved not only in acquisition but in processing and interpretation to a desired level of accuracy.

References

Green, E.P., Mumby, P.J., Edwards, A.J. and Clark, C.D. (Ed. A.J. Edwards) (2000). Remote Sensing Handbook for Tropical Coastal Management. Coastal Management Sourcebooks 3. UNESCO, Paris. x + 316 pp. + 24 colour plates. ISBN 92-3-103736-6.

Mumby, P.J., Green, E.P., Edwards, A.J., and Clark, C.D. (1999). The cost-effectiveness of remote sensing for tropical coastal resources assessment and management. Journal of Environmental Management 55: 157-166.

Green, E.P., Mumby, P.J., Clark, C.D., Edwards, A.J. and Ellis, A.C. (1998). Remote sensing techniques for mangrove mapping. International Journal of Remote Sensing 19 (5): 935-956.

Mumby, P.J., Green, E.P., Clark, C.D., and Edwards, A.J. (1998). Digital analysis of multispectral airborne imagery of coral reefs. Coral Reefs 17 (1): 59-69.

Green, E.P., Mumby, P.J., Edwards, A.J., Clark, C.D. and Ellis, A.C. (1998). The assessment of mangrove areas using high resolution multispectral airborne imagery. Journal of Coastal Research 14 (2): 433-443.

Mumby, P.J., Clark, C.D., Green, E.P. and Edwards, A.J. (1998). Benefits of water column correction and contextual editing for mapping coral reefs. International Journal of Remote Sensing 19 (1): 203-210.

Mumby, P.J., Green, E.P., Edwards, A.J. and Clark, C.D. (1997). Coral reef habitat mapping: how much detail can remote sensing provide? Marine Biology 130: 193-202.

Mumby, P.J., Green, E.P., Edwards, A.J. and Clark, C.D. (1997). Measurement of seagrass standing crop using satellite and digital airborne remote sensing. Marine Ecology Progress Series 159: 51-60.

Mumby, P.J., Edwards, A.J., Green, E.P., Anderson, C.W., Ellis, A.C. and Clark, C.D. (1997). A visual assessment technique for estimating seagrass standing crop. Aquatic Conservation: Marine and Freshwater Ecosystems 7: 239-251.

Mumby, P.J., Green, E.P., Clark, C.D. and Edwards, A.J. (1997). Reef habitat assessment using (CASI) airborne remote sensing. Proceedings of the 8th International Coral Reef Symposium, Panama, June 24-29, 1996, 2: 1499-1502.

Green, E.P., Mumby, P.J., Edwards, A.J. and Clark, C.D. (1997). Mapping reef habitats using remotely sensed data: exploring the relationship between cost and accuracy. Proceedings of the 8th International Coral Reef Symposium, Panama, June 24-29, 1996, 2: 1503-1506.

Green, E.P., Mumby, P.J., Edwards, A.J., Clark, C.D. and Ellis, A.C. (1997). Estimating leaf area index of mangroves from satellite data. Aquatic Botany 58: 11-19.

Green, E.P., Mumby, P.J., Clark, C.D., Edwards, A.J. and Ellis, A.C. (1997). A comparison between satellite and airborne multispectral data for the assessment of mangrove areas in the eastern Caribbean. Proceedings of the Fourth International Conference on Remote Sensing for Marine and Coastal Environments, Florida, 17-19th March 1997, 1: 168-176.

Clark, C.D., Ripley, H.T., Green, E.P., Edwards, A.J. and Mumby, P.J. (1997). Mapping and measurement of tropical coastal environments with hyperspectral and high spatial resolution data. International Journal of Remote Sensing 18 (2): 237-242.

Green, E.P., Mumby, P.J., Edwards, A.J. and Clark, C.D. (1996). A review of remote sensing for the assessment and management of tropical coastal resources. Coastal Management 24: 1-40.