Myanmar Protected Areas: Context, Current Status ... - Istituto Oikos

Step 4. Change detection analysis
In order to detect and to evaluate the land cover changes (decreasing and recovering process over time)
the multi-temporal Landsat MSS and ETM+ images, acquired respectively on 23 November 1978 and 17
November 2001 at full vegetation cover in the cool season, were initially pre-processed and adopted for
a NDVI (Normalised Difference Vegetation Index) Image Differencing algorithm for change detection.
Changes were classified into 5 categories such as “increase”, “moderate increase”, “no-change”, “moderate
decrease” and “decrease” of NDVI change. A final map illustrating the types of change found in the study
area was produced.
Land cover change in Rakhine Yoma Elephant Range WR
In-depth Study of Rakhine Yoma Elephant Range Wildlife Reserve
4.2 Results
Description of land cover classes
A brief description of each land cover classes is presented, including mention of the causes of
degradation.
Mangrove Forest
This class can be commonly encountered around the coastal area, principally along the estuaries. Main
species are trees such as Avicennia officinalis and Rhizophora spp. Largely diffused by human activities is
the palm Nipa fruticans, used for its fibres. Even if their extension is limited as total surface (only 2% of
the study area), mangrove forests cover a big portion of the seaside. The importance of this ecosystem
for the coastal region is very high in terms of biodiversity, coastal stabilisation, primary production
and provision of nursery habitat for marine fish. The main threats to this habitat are the permanent
conversion to agriculture or fish nurseries, and the degradation due to over-collection of fuel wood and
poles.
Western Coastal and Valley Agricultural Areas
This class comprises three different kinds of vegetation: the large agricultural fields situated on the
coastal region; the small farms in the narrow valleys of the eastern side of the Rakhine Yoma; the seminatural
dune and beach forests, often substituted with artificial plantation of palm species (such as
coconut). The main crops are: dry paddy rice; different kinds of nuts and beans; chilli; tobacco. The
surface of this class is around the 4% of the total.
Western Mixed Deciduous Forest
This forest type is encountered in the lowest western slopes of the Rakhine Yoma, where the evergreen
species are reduced in abundance and mostly only deciduous trees are present: Xylia dolabriformis
(Pyinkado or Iron Wood), Lannea grandis (Nabe), and Lagerstromea speciosa (Pyinma). Due to their close
location to the most inhabited areas of the coastal region, this class is highly threatened by human
pressure for timber, fuelwood and housing material. Moreover, as a result of traditional practices of weed
and vermin control in the bordering agricultural areas, these forests are usually disturbed by fires. As a
result, generally the fertility of this class seems to be severely degraded. Some artificial plantations have
been found of Hevea brasiliensis (Rubber tree), Tectona grandis (Kyun or Teak), and Xylia dolabriformis,
established mostly more than 10 years ago. The surface of this class is limited, covering only around the
3% of the study area.
Closed Semi-Evergreen Forest
An intermediate step between the lowland mixed deciduous woodland and the evergreen forest present
at the higher altitude, in this class deciduous and evergreen species are intimately mixed together. The
most common species are Xylia dolabriformis and Dipterocarpus spp. (Kanyin), which are particularly
characteristic of this ecosystem and can both form almost pure patches. Other trees occurring are Lannea
grandis, Lagerstromea speciosa, as well as other evergreen species. Bamboos, like Bambusa polymorpha
(Kyathaung Wa), and rattans (Calamus sp) are also found. The overall status of these forests seems to
be better than the previous Western Mixed Deciduous Forest, although they cover only 4% and are
increasingly threatened by human activities such as wood collection and fire disturbances.
138 139