10
3 LAND COVER DYNAMICS IN THE PROJECT AREA
Satellite data from the Forestry Commission relating to the period 1990 to 2010 broadly classifies land cover in Ghana into five types; Wetlands, Forestlands, Croplands, Grasslands
and Settlement cover
3
. Details of the type of satellite data and modalities of classification can be found in appendix 2. Despite that the data is about five years old and extremely
generalised for a local study such as the one being undertaken, it is the only available source for understanding land cover dynamics for a longer period such as two decades. The need for
a more refined, detailed and updated satellite imagery to better inform spatial analysis of land cover dynamics has not only been identified but the process of acquisition has started.
Understanding and quantifying mangrove changes as well as identifying areas of gains and losses better serves the overall objective of the project. The Ankobra estuary is dominated by
two main species of mangroves – Rhizophora and Avicennia. However, the broad land cover
data does not specifically classifies mangroves as a distinct land cover type. From the modalities of existing land cover classification, ecosystems literature and observations of the
study area, wet and forest lands appear to be the closest proxies to mangroves. Subsequently, the dynamics, trends and patterns relating to the two land cover types have been emphasised.
3.1 Land Cover Changes and Composition in the Study Area, 1990 and 2010
The study area which is within a 2.5 km buffer along Ankobra River from the estuary to Kukoavile covers about 100 km
2
. The spatial planning guidelines of Ghana also prescribe a 50 metre
4
buffer reservation along water bodies. This section therefore examines land cover composition and dynamics between 1990 and 2010 for two spatial scales; the 50 metre buffer
and the entire study area 2.5 km buffer.
3.2 Land Cover Dynamics in 50m Buffer
3.2.1 Land Cover Composition, 1990 and 2010
The 50 meter buffer stretches from the estuary to Kukoavile extending over an estimated 19.5 m
2
total land area. The area was largely constituted by forest and wetlands in 1990 as the two absorbed about 99 percent of the total land area with the former holding the highest 50
percent as shown by figure 3.4 There was no settlement cover within the buffer in 1990 whiles grass and crop lands held only 0.9 and 0.1 percent of the buffer area respectively.
Evidence of massive human interactions within the 50 meter buffer area over the two-decade period is observed. From table 3.1, forest lands decreased woefully by about 380,000 m
2
by 2010. Contrary to the decline in forest lands, other land cover types appreciated. Wetlands
increased from about 950,000 m
2
in 1990 to 1.1 million m
2
in 2010, triggering an increase in share from slightly below 49 percent to over half 56 percent. Wet and forest lands
accounted for 87 percent – about 12 percent less of the previous share - of the buffer area in
2010. Some settlements expanded to cover about 12,000 m
2
of the buffer area while grass land pushed its share of total land area from below a percent to close to a tenth 8.5 percent
during the two decades under consideration.. In the quest for livelihoods, farming activities increased during the period as the croplands increased significantly from just about 3,000 m
2
to 79,000 m
2
.
3
Forestry Commission, 2013, Land Use and Land Use Change and Forestry, Ministry of Land and Natural Resources.
4
Ministry of Environment, Science and Technology, Town and Country Planning Department 2011, Zoning Guidelines and Planning Standards. Republic of Ghana.
11
Figure 3 Land Cover Composition in 50m Buffer along Ankobra River
Source: Spatial Solutions 2015 Based on Forestry Commission ’s Land Cover Data
The annual rate at which farming activities are undertaken in the 50 meter buffer preservation far exceeds any other land cover change as croplands grew by about 18 percent annually
shown by table 1. On the other hand, forestlands declined by an alarming 2.4 percent annually over the period. The rapid growth of croplands juxtaposed by the steadily fall in
forestlands presents perhaps, at the local level, the competing strands between the quest for economic development livelihoods and environmental preservation. However, it must be
emphasized that when well-managed, the two can be mutually complementing. Grass lands also increased at a significantly high rate compared with a mild increase in wetlands. Does
the growth in wetlands connote no loss in the land cover within the 50 m buffer over the period?
Table 1 Summary of land Cover Composition within 50m buffer
Area ‘000
sqm Share
AGR 1990 2010 1990 2010
Wetlands 950
1,103 48.9 56.4 0.7 Forestland 973
594 50.1 30.4 -2.4
Cropland 3
79 0.1
4.1 18.1
Settlement 0 12
0.0 0.6
Grassland 17 166
0.9 8.5
12.1 Total
1,942 1,955 100 100
Source: Spatial Solutions 2015 Based on Forestry Commission ’s Land Cover Data
3.2.2 Wetland Change, 1990 – 2010
