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8/14/2019 Songkhram Habitat Classification
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Habitat mapping forfisheries using remote sensing and GIS techniques in
Lower Songkhram River Basin
Ubolratana Suntornratana1, Thiha2, Sekson Daungsri3, Edward L. Webb4 and Anupong
Sanitchon5
1 Surin Inland Fisheries Research and Development Centre, 2 & 4 Asian Institute of Technology, 3 Maha Sarakhram
Inland Fisheries Research and Development Centre, 4 Nongkhai Inland Fisheries Research and Development Centre
ABSTRACT
Remote sensing, a technique of investigating the earth from satellite platform with the use of
Electro-Magnetic Radiation (EMR), has a potential to help support fisheries study through
investigating spatial distribution of habitats important forfi
sheries production and managementin integration with GIS technology. The main objective of this study was to map habitats, which
are essential forfisheries production in the lower part of the Songkhram River Basin. The core
methodological steps involved delineating inundated floodplain, which expands during wet
season and estimating reproductive areas forfisheries production and also other type of habitats
important for aquatic production through ancillary GIS analyses.
Two Landsat ETM images from 17 September 2000 and 18 March 2003 were classified into
thematic land cover maps using supervised classification with maximum likelihood method. A
self-developed classification protocol was used to map the habitat across dry and wet seasons
of the study area. Prior to the image classification, standard preparatory image processing oflayer stacking, image co-registration, subsets and cloud removal were performed using ERDAS
image processing software. The orthorectified TM image from 6 November 1992 was used as
the master image for the image co-registration.
A system of land cover classification using satellite data, then, combined with field
observations presented of habitats types. Ground truth data was collected from several
field visits to the study area (Lower Songkhram River Basin) during July to August 2006
using Garmin Map 60 GPS. Field data collection was supplemented with information from
topographic maps at a scale 1:50,000 and field observations by the research team.
Thematic habitat maps from preliminary analysis to serve fisheries field of studies exhibited
ten major habitats in the lower Songkhram River Basin. Permanent water bodies of the main
Songkhram River and its tributaries, other water bodies, inundated flooded areas mostly
associated with riparian mixed vegetation, paddy fields (lowland) and some agricultural crops
in wet season represent the most important habitats essential forfisheries production inside
study area. Inundated flooded extended in the wet season was more than 50,000 hectare. It is
anticipated that this information combined with spatially explicit GIS maps could help fishery
managers to link with catch information to estimate catch production in the lower basin by
habitat types and/or helping present a scenario offish stock for better management. However,
the completion of habit mapping forfisheries would require an accuracy assessment to evaluate
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the correctness of habitats. In addition, revision of classified habitat maps, by integrating ground
truth data, is recommended for further spatial analyses relative to future fishery management.
INTRODUCTION
Low-land floodplain is the important system of wetland and also a sensitive ecosystem which
requires a proper monitoring system to determine the change. This area can produce big amount
of production and generate the big food chain to serve many living organism from the bottom
to top level (Bayley 153 58; Chapman and Chapman 23 30). However, the large variation
is affect by a seasonal and inter-annually condition, especially fisheries sector. The fisheries
production potential in the floodplain river system is directly related to the duration and extent
offloods and consequently led to potential offisheries production.
The Songkhram is very well known an important floodplain ecosystem with its huge area
covers extensive in the lower part of the basin (David Balke and Rattaphon Pitakthepsombat
118 1; Interim Committee for Coordination of Investigations of the Lower Mekong Basin
1 11). There were record of many Mekong species migrate to this river system and utilized
this area as a spawning ground and nursing ground. This caused of a big amount offisheries
production occurred every year during wet season (AMCF 1 34; Sjorslev et al. 5 19;
Suntornratana et al. 29).
Estimated fisheries production roughly in the lower part of the basin which covers around
4,000 km2
was possible more than 16,000 tonnes (AMCF 1 34; Sjorslev et al. 5 19). Theextrapolation on production conducted by introducing a simple interview survey altogether with
broad inventory on communitys fisheries. The used of Geographic Information System (GIS)
was to estimate area of habitat in order to support assessing fisheries production. However, the
suggestion provided was a proper system to estimate habitat area could help better assessing
fisheries production.
This paper, then, presented a methodology used the technique of Remote Sensing (RS) and
Geographic Information System (GIS) to visualize habitat and monitor the surface changed,
especially flood extended area which is important forfisheries production. The RS technique
considered an observation from space though time series which can help monitoring surfacechange seasonally (Butleret al. 1 165; Dekkeret al. 211 25; Ellis and Woitowich 98 109).
The techniques is also useful in assessing the status of the environmental system and long-term
monitoring habitat change to support decision making forfisheries management foe better
sustainable used.
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Habitat mapping forfisheries using remote sensing and GIS techniques in Lower Songkhram River Basin
METHODOLOGY
Habitat classification mapping were generated used of Remote Sensing (RS) and Geographic
Information System (GIS) technologies which basically apply a remote sensed data integratedand organized through a computer based systems. The core analytical procedure included two
phases: habitat classification and spatial analysis. Habitat classification phase concerned with
the classification of remote sensing data into thematic habitat maps. Spatial analysis dealt with
the quantification of the seasonal dynamics of majorfishery habitats through a change vector
analysis.
Framework of the study
Overall simple framework for assessing fisheries sector is the information of habitat and
fisheries should be able to integrate and combine for better assessing this sector. The structure
of integrating the different types of information presented as in Figure 1. Spatial implication
used of remote sensed datasets can visualize and monitor various types of habitat, included
the habitat important forfisheries production. This classified habitat, then, can be merged with
a non-geographic information from other surveys and present scenario offisheries situation
and monitor the trend of change. For the main purpose to conduct habitat classification using
Remote Sensing and GIS techniques, the diagram presented process of Land covered analysis.
Framework for integrated remote sensed data with interview survey for assessingFigure 1.
fisheries and process of land cover analysis for habitat classification.
RS and GIS system to
visualize image and
process spatial data
Image processing
Ground reference
Image classification
Spatial anlysis
Remote sensed data for
habitat classification
Spatial/ Geographic
dataset (Landset ETM
(Sep 2000 and Mar 2003)
Thematic maps
provided detail habitat
class with
boundary/area
Non-geographic
dataset on fisheries
Information in
fisheries which
presented in simple
tabular
Statistic technique
for manipulating
result
Scenario of
integrating data-
sets supported
simple assessing
process
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Study area
The lower part of Songkhram River Basin (Figure 2) was selected for study as it is very well
known an important lowlandfl
oodplain in the upper northeast region of Thailand. The areaselected for habitat classification was around one-third of the total basin area which covers
more than 12,700 km. It locates between latitude 14 14' and 18 98', longitude 103 75' and
104 48'.
The ecosystem of this area is mainly a wetland consists of special vegetation and the extent
of inundated flooded occurred annually for two to three month during wet season. This natural
event generate huge fisheries production to serve local communities in the area. Information
from various studies showed big amount offisheries production occurred every year and many
reports showed the evidence offisheries production was generate due to large area offloodplain
in this river system (AMCF 1 34; Yingcharen and Virapat; David Balke and RattaphonPitakthepsombat 118 1).
Study area in lower part the Songkhram River Basin, upper northeast region of ThailandFigure 2.
Data selection for habitat classification and data source
Two Landsat ETM+ images from 18 March 2003 and 28 September 2004 were purchased from
Michigan State University. The orthorectified TM image from 6 November 1992 and ETM+
image from 17 September 2000 were downloaded from the Global Land Cover Facility (http://
glcf.umiacs.umd.edu/index.shtml) (Table 1). Topographic maps at a scale of 1: 50,000 covering
H.NamYam
Nam Oon
H. K
ho
ngH.H
i
NamM
ao
1040'0"E
1040'0"E
1030'0"E
1030'0"E
180'0"N180'0"N
170'0"N170'0"N
River
Flooded area
0 20 4010
km
LAO PDR
THAILAND
Songkhram
River Basin
THAILAND
LAO PDR
CAMBODIA
VIET NAM
Gulf of Thailand
NamSongkhram
Mekong
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Habitat mapping forfisheries using remote sensing and GIS techniques in Lower Songkhram River Basin
the lower part of Songkhram River Basin were obtained from Technical Advisor Division
of the Mekong River Commission (TSD-MRC). Those were used as reference and training
materials required for image registration, evaluation of habitat reflectance signatures and image
classification
List of satellite images data used for habitat classification and co-registration parametersTable 1.
Satellite and sensor Acquisition date Sun azimuth
and angle
Ground
resolution
RMS
(root MSE)
Source
Landsat 7, ETM + 17 September 2000 118.62, 60.87 30 x 30 m 12.8 m GLCF
Landsat 7, ETM + 18 March 2003 119.68, 55.73 30 x 30 m 13.2 m MSU
Landsat 5, TM 6 November 1992 137, 46 30 x 30 mOrthorectified
(Master) imageGLCF
Landsat 7, ETM+ 26 April 2003 95, 64 30 x 30 m 9.04 m GLCF
Landsat 7, ETM+ 28 September 2004 125.94, 58.60 30 x 30 m 10 m MSU
Image preprocessing
Prior to the image classification, we performed standard preparatory processes of image
geometric correction, image-coregistration, image subsetting and cloud removal. First, all
Landsat images were geo-referenced into Universal Transverse Mercator (UTM) zone 48, using
an image-to-image registration method. Second, geo-referenced images were co-registered to
the orthorectified TM image from 6 November 1992 for their topographic errors due to terrain
effect. Third, the datum of all coregistered images was transformed into Thailand/Vietnamdatum. Data transformation was necessary because all the topographic maps, thematic GIS
layers and Global Positioning System (GPS) used the Thailand/Vietnam datum while all the
Landsat images were projected in World Geodetic System 84 (WGS 84). Finally all images
were subsetted to exclude the areas outside of the area of interest from being considered.
Ground reference data collection
Ground reference data required for the reflectance signature development for the imageclassification was collected from an intensive field work during the period between July and
August 2006. The research teams recorded approximately fifty ground reference points covering
all major habit types, using a GARMIN GPS 60 receiver. In addition, a self-designed field data
collection sheet was used to record the attribute data such as surrounding land cover, human
activities and other environmental variables (e.g. soil erosion). Reflectance signatures for each
habitat type were developed based on ground reference data, training and reference materials as
well as researchers familiarity with the area.
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Image classification
Supervised classification with maximum likelihood classifier classified all image pixels of each
Landsat image into nine habitat types (Table 2).
General description of habitat types in the lower Songkhram River BasinTable 2.
Habitat type Description Additional information of habitat
Permanent water body
(Channel-type) *
Main Songkhram River and its tributaries as well
as other small streams
Considered an important spawning and nursing
ground for many riverine species migrated
from the Mekong to the Songkhram and also
the channel for many species to migrate onto
floodplain of the Songkhram (Suntornratana et
al. 270 80).
Permanent water body
(Non-channel type)*
A Lentic water system such as several sub-
categories of natural and man-made water bodies
such as swamp, reservoir, pond, weir, etc.
Considered an important fishing ground which
fishing activities occurred almost all year round.
This area could be a dry-refuge season area for
stock of many fish species in the Songkhram.
Agricultural crops Man-made plantations mainly Rubber (Havea
brasiliensis) andEucalyptus spp., cash crops such
as Sugarcane
The ages of plantation ranged between 4 to > 10
years. This habitat had dense canopy cover and
uniform pattern.
Dipterocarps-
dominated mixed
vegetation
Majority are natural vegetation mixed sometimes
with enrichment plantations in privately owned
patches and community forests. Usually this
vegetation had two layers, with the Dipterocarps
being at the canopy layer
Undergrowths include bushes, herbs and shrubs.
Riparian mixed
vegetation*
Wetland natural vegetation with non-canopy
trees. Majority of vegetation are dwarf and bushy,
and highly associated with bamboos, shrubs and
grasses.
Mainly found on river banks and inundated
lowland areas. This zone also considered a
riparian flooded forest which important as a
spawning and nursing ground area for many fish
species. It was also important fishing habitat
during wet season.
Paddy field * Includes two types of rice fields: wetland rice
fields and upland rice field. Wetland rice fields are
abandoned in the wet season and rice is grown
when water recedes in dry season. In the upland
rice fields, irrigated rice is grown throughout the
year.
Considered an important habitat forfisheries
production, especially for lowland paddy which
normally flooded during .
Barren land Man-made clearings for housing complex and
other infrastructure such as roads and bridges.
Mixed vegetation Majority is mixed vegetation in relativelyhigher ground, rarely mixed with riparian mixed
vegetation. Majority appears natural vegetation,
rarely mixed with plantations, especially private
owned plots and community forests.
Settlement Built-up areas such as highways, feeder roads,
villages and town, rarely mixed with home garden
and road-side vegetation
This category was spectrally highly variable due
to the association with diversified home garden
species and agricultural crops.
* Considered an important habitat potentially generated fisheries production.
Spatial analysis began with performing a neighbourhood analysis. Neighbourhood analysis
with three by three pixel kernel function eliminated the isolated image pixels that were likely
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Habitat mapping forfisheries using remote sensing and GIS techniques in Lower Songkhram River Basin
to be misclassified and maintained the spatial cohesiveness among image pixels. Subsequently,
non-channel type and channel type permanent water bodies and inundate flooded area were
extracted from the dry and wet season habitat maps and were vectorized. A GIS overlay
between wet and dry season habitat GIS maps produced a map showing inundated flooded
bodies in the wet season. Area statistics of the extended water body was calculated from theattribute table of the output map.
Spatial analysis
Supervised classification was one of the post classification techniques that have been widely
used in several land cover/use and habitat mapping studies. The method has also proven to be
comparable with other classification methods, such as unsupervised classification and hybrid
method, in terms achieving high classification accuracies.
Result of habitat classifi
cation
Followed the RS and GIS techniques, images have been identified and estimated for area
covered in the lower part of the Songkhram River Basin into different categories of nine major
habitat types. Output from image classification included dry and wet season maps showing
major habitats in the lower part of the basin (Figure 3 and 4).
Thematic mapping classified habitat into nine categories in the lower part of theFigure 3.
Songkhram in dry season
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Thematic mapping classified habitat into nine categories included inundated floodedFigure 4.
extended area in the lower part of the Songkhram in wet season.
During peakflooded period in September 2000, the image presented clearly offlood-pulse
extent covered lowland area of the basin. This area determined a large area of habitat essential
forfisheries production which possibly changed every year due to the rate of precipitation, run
off from Songkhram sub-catchments and also the water level in the mainstream Mekong.
Beside major output of two thematic maps showing the habitat types in the lower
Songkhram River Basin, an ancillary statistics: area statistics for each habitat types and
seasonal change was also summarized. The statistics outputs were exported to excel format and
delimited formats for further calculation. Habitat-wise area statistics across two seasons are
given in Table 3. The most important output from the spatial analysis was the map showing the
spatial distribution of inundated water bodies in the wet season. Clearly shown of an extended
inundated flooded was approximately 53,000 hectare.
Even though the different of area in all habitat types could not be compared directly due tothe limitation to get the images in between two seasons the same period offlooded cycle in a
year. This flooded area extent presented could possible determine the area of paddy field which
clearly different between the two seasons for around 36 percent of the total area of paddy field
inside study area in dry season. However, the change of paddy area was under the assumption
of no change over time in two years.
In relevant to the extent flooded area and all water bodies of both channel and non-channel
types, it was considered that the class of Riparian Mixed Vegetation was also the important
habitat forfisheries production, especially during wet season. This area cover found along the
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Habitat mapping forfisheries using remote sensing and GIS techniques in Lower Songkhram River Basin
river/stream channel and scatter around an inundated flooded area. Statistic showed more than
ten percent of the total area and seemed to be decrease by time.
Area statistics of nine habitat types in the lower part of the Songkhram River Basin. (*)Table 3.
indicated the extent water body during peakflooded in the wet season
Habitat type Wet season (2000) Dry season (2003) % different
between
season *Area (ha) % Area (ha) %
Dipterocarpus-dominated forest 15,291.4 4.4 14,097.2 4.0
Paddy 91,838.7 26.2 144,226.2 41.1 -36.3
Permanent water body (river and stream) 6,883.0 2.0 2,037.3 0.6 -237.8
Permanent water bodies (non-channel type) 12,232.3 3.5 11,406.1 3.3 -0.1
Riparian mixed vegetation 45,414.1 13.0 39,993.2 11.4
Mixed vegetation 90,858.8 25.9 96,254.1 27.5
Agricultural crops 25,697.3 7.3 18,969.2 5.4
Settlement 10,340.0 3.0 11,408.7 3.3
Barren land 0.0 0.0 722.0 0.2
Inundated flooded extended* 51,803.9 14.8 0.0 0.0
Cloud 11,446.7 3.3
Total area 350,359 100 350,560.6 100
* The different of area changed was under the assumption of land used pattern in the lower part of the Songkhram River Basin
was not significantly change during three years.
Recommendation
The result obtained of this trial study have demonstrated the possibility of habitat classification.
Application of RS and GIS can help visualizing various types of habitat included habitat
essential forfisheries production like an inundated flooded area, riparian mixed vegetation,
paddy and water bodies inside study area. However, the difficult was to encounter for
identification ground control points on the image due to the low resolution.
With the completion of habitat classification and mapping forfisheries field of study,following technical recommendation are made for the improvement of habitat maps for further
spatial analyses.
The classified habitat maps are subject to accuracy assessment to evaluate the correctnessof each habitat type.
Revision of classified maps could be necessary using ground truth data. Ground truth datacollection can be done during accuracy assessment in which randomly selected habitat
mapping places are field-visited.
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Additional spatial information should be integrated to rectify classification error. Forexample, existing land use maps, cadastral maps and topographic data are useful to
improve the accuracy.
Required more satellite images of different seasons in the same period of year (fl
ooded cycle) for better comparison of the change over time and seasonal affect of change.
According to the dense of riparian vegetation affected to reflectance, therefore, area offlooded extent underneath of bushy dense could not be clearly detected. Field survey,
then, required in order to be able to indicate flooded extent in this habitat class.
REFERENCES
AMCF. 2003. Baselinefi
sheries the Lower Songkhram Basin; Draft report. Udonthani,Thailand. 34 pp.
Bayley, P. B. 1995. Understanding large river-floodplain ecosystems. Bioscience 45 p.
153 158.
Butler, M. J. A et al. 1988. The Application of Remote Sensing Technology to Marine Fisheries:
an Introductory Manual. Rome: FAO.
Chapman, L. J and C. A Chapman. 1993. Fish populations in tropical floodplain pools: a re-
evaluation of holdens data on the River Sokoto. Ecology of Freshwater Fish 2.2 (1993):p. 23 30.
David Balke and Rattaphon Pitakthepsombat. 2006. Situation Analysis: Lower Songkhram
River Basin, Thailand. Mekong Wetland Biodiversity Conservation and Sustainable Used
Programme (MWBP). Bangkok. 118 pp.
Dekker, A. J et al. 1992. The effect of spectral bandwidth and positioning on the spectral
signature analysis of inland waters. Remote Sensed Environment. p. 211 225.
Ellis, T. J and W. A Woitowich. 1989. An Overview of the Use of Remote Sensing for the Studyof Rivers and River Systems. Canadian Special Publication of Fisheries and Aquatic
Sciences.
Khon Kean University. 1984. Interim Committee for Coordination of Investigations of
the Lower Mekong Basin. Study of Fisheries Impacts of Nam Songkhram Basin
Development. pp 488.
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Habitat mapping forfisheries using remote sensing and GIS techniques in Lower Songkhram River Basin
Sjorslev, J. G et al. 2001. Combining Sampling and Census Approaches for Fisheries Habitat
Assessment in Songkhram River Basin, North East Thailand. Phnom Penh, Cambodia:
Mekong River Commission.
Suntornratana, U et al. 2002. Migration Onto the Floodplain of the Songkhram River Basin.Phnom Penh, Cambodia: Mekong River Commission, 2002.
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Songkhram River, Thailand. Phnom Penh, Cambodia: Mekong River Commission
Secretariat.
Yingcharen and Virapat, C. 1998. Final Report Aquatic Ecology and Fisheries
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Recommended