The research programme can be divided into three phases: pre-fieldwork, field expedition and further analysis & output.
Aim: To produce a provisional map of the natural vegetation communities.
Whilst still in the UK, a provisional vegetation map could be produced in the Department of Geography using remotely sensed data. This work combines data from three sources, offering different measurements at different scales (resolutions) - Landsat thematic mapper (TM) satellite data, airborne synthetic aperture radar (AIRSAR) images and black and white aerial photographs.
Thus, a preliminary vegetation classification is developed. The next step is to overlay an X-Y co-ordinate grid on the map This study chose the international UTM (Universal Transverse Mercator) grid which is one of the co-ordinate systems used by hand-held GPS units. Together, the map and GPS will allow the user to position themselves precisely in the field. Finally, a hardcopy (print-out) of the new map is produced and it is ready for testing in the field.
Aim: To use field surveys to develop and enhance Phase 1 interpretations.
Conventional maps are really only of use for navigating in the vehicle - away from roads there simply aren't enough landmarks to allow you to use them for navigation purposes. Most of the land is simply classified as woodland or swamp. The seasonality of the wetland introduces further complications. The perimeter of wetland features such as lakes will alter, according to the amount of rain which has fallen recently.
Instead, the new vegetation map with its UTM co-ordinate overlay and hand-held satellite navigation equipment (GPS) are used to "fix" our location. The open nature of the wetland and savanna areas gives unobstructed views to the sky. This allows very clear communication with the network of satellites, giving us positional data with very low errors.
|The vegetation team began with a reconnaissance survey of the principal plant communities. Sampling points were then selected to reflect the major ecological zones and areas of vegetation transition. The team worked along east-west aligned transects with the initial focus on the collection of point centre quarter method (PCQM) data, supported by detailed ecological descriptions and assessments of structure and species.
The extent of sampling in each area depended on
(i) the diversity of vegetation and
(ii) the degree of correlation between the satellite-derived map and the vegetation found on the ground.
In addition, general observation and collection of specimens was carried out to give a fuller description of the vegetation (particularly the herbaceous and shrubby components).
Specimens are currently being identified using the resources of the Herbarium and Library at Royal Botanic Garden, Edinburgh and Kew.
Complete sets of specimens will be deposited with the appropriate institutions in Belize, one set being held at the La Milpas Research Station. Investigations will aim to yield a clearer understanding of the environmental influences controlling plant communities.
|The soils team also worked along the transect lines, sampling to reveal the variability in soil properties within and between the vegetation zones.
Field description of the soils noted features such as surface vegetation and litter cover, soil colour, texture, the distribution of roots and moisture content. A key measurement is the height of the local water table relative to the soil surface, as soil moisture availability is an important control on the vegetation in wetland areas.
Samples of soil and soil-water were collected for later laboratory analysis, both in Belize and upon return to the UK.
Properties investigated include organic matter content, root biomass, texture, pH, exchangeable cation levels, available phosphorous content, total nitrogen and conductivity
The soils were classified using the system developed in King et al.'s 1992 Land Resource Assessment of Northern Belize
In conjunction with the vegetation and hydrological data, this work:
identifies broad scale soil-plant community relationships,
allows the identification of pedological, hydrological and anthropogenic influences upon the vegetation, and
identifies areas suitable for regeneration or commercial activity.
|While the research emphasises the description of the habitats based upon vegetation types, information about the hydrological processes is invaluable in assessing conservation priorities and understanding the ecological mechanics of the system. Water quality assessments were made in the field,using a range of portable electrode devices. Properties such as dissolved oxygen content, pH and conductivity were recorded.
Furthermore, in the two most common vegetation types - wetlands and savanna - a combination of geostatistical analysis and a very detailed "nested" sampling strategy allowed us to estimate the spatial scale of change in two key variables: salinity and pH.
Permanent markers were inserted to allow Programme for Belize staff to carry out long-term monitoring.
The narrow timespan of this field study means that field hydrological measurements had to be supplemented with data obtained from interviews with the forest rangers and local inhabitants. This allows broad scale estimates to be made regarding the extent, distribution and duration of floodwaters during the wet season.
Attempting to conserve a large area of land such as the RBCMA requires careful management, particularly if the area includes villages where local people have previously exercised their traditional hunting rights. Even amongst conservationists, there is a debate as to whether "conservation" really means "preservation", or if a limited amount of "development" is required in order to secure the long term future of the land, plants, animals and people living there.
The results of these investigations form the basis for a series of individual undergraduate dissertation submissions, held at the University of Edinburgh.
Completion of the detailed soil and water laboratory analysis in the Department of Geography Laboratories. (This was acheived in August 1997, the data are presently undergoing statistical analysis.)
Completion of the identification of plant specimens using type-specimens from UK collections. (This is almost complete, a full species list for the area will be published shortly).
The collation and distribution of the information in a readily accessible form.
The final output will include :
A comprehensive GIS-derived map of vegetation zones within the study area including demarcation of key sites, corridors and areas requiring special attention or protection.
A floral and soil inventory.
Several Programme for Belize staff trained in wetland-savanna floristic and soil survey techniques, allowing them to continue and extend the work begun in this project.
Four sets of plant material collected, identified and lodged in herbariums for use in further studies.
|The map shown to the left is an example of the output from the project. It was produced in Edinburgh by Mary Vasquez, Chris Place and Neil Stuart. It shows the RBCMA classified by vegetation types:
BLUE - Lagoons and other water features
MAGENTA - Wetlands
RED - Riverine scrub mangrove
GREEN - Thicket and gallery forest
PALE YELLOW - Grassland and savanna
PALE ORANGE - Savanna and savanna orchard
GREY - Marl flat.
The GIS allows us to measure for the first time the area of each vegetation type present on the reserve.
The largest single class is the "Grassland and savanna" (c. 40%), with both the "Thicket and gallery forest", and "Savanna and savanna orchard" classes second equal at c. 20% each. The final 20% is composed of a mosaic of wetland vegetation types.
The classified image shown here is the copyright (©) of The University of Edinburgh and Programme for Belize.
The survey will produce a number of reports directed towards the practical use of its results, which should feed directly into the work of the Programme for Belize, and their as yet embryonic management plans for the area. In addition the project will identify and inform Programme for Belize of areas requiring further research.
The Booth's River Survey will lend itself to promotion through press and scientific journals and to publicity at many levels. Research will be disseminated through reports, published articles and a post-fieldwork conference in Belize, detailing its preliminary findings. The final results will also be made available through the expansion of these World Wide Web pages.
Qualitative results from the project can be evaluated in terms of the use given by the Programme for Belize Board of Management, to the results of the surveys, the general degree of collaboration and the training of high quality Belizean filed workers. Since it is likely that further scientific research will be indicated, it would be an encouraging outcome to see the continuing collaboration between all institutes involved in future research proposals, funding negotiations and the implementation of research programmes.