application of gis and remote sensing technique to assess the status of forest types of the southern...
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Application of GIS and Remote sensing technique to assess the status of forest types of the Southern Eastern Ghats, India
G.AreendranWWF-India
Society for conservation GIS10th Annual International Conference,Monterey,California,2007.
• The Eastern Ghats form a broken chain of mountainous terrain spreading in the states of Orissa, Tamil Nadu, Andhra Pradesh and two districts of Karnataka.
• Location- 11 ° 30 ‘ - 22° N latitude and 76 ° 50 ‘ - 86 ° 30 E longitude.
• Area 75,000 sq.kms of forested area with an average width of about 100-150 km.
• Maximum Altitude recorded at 1762 metres.Average elevation is 750 metres.
STUDY AREA
• The present study area is located between 7831’E- 8016'9"E and 1451'N –1055N
• Assemblage of discontinuous hill ranges, plateaus and escarpments.
• The entire Eastern Ghats constitutes major water sheds of many big rivers.
• The scope of the present study is restricted to stretches of the middle eastern Ghats and the southern eastern ghats mountains
Topography & Climate
• Geologically the Eastern Ghats present a rocky landscape, with quartzite rocks
• Average temperatures range from 20-35 ° C and can go upto 45 °C during the summer months ( April –June)
• Mean annual rainfall ranges from 60-105 cms exhibiting a semi arid climate
Objective of the study
• To prepare various thematic maps of the study area using Geographic Information techniques
• Map the existing vegetation of the region with a focus on forest community, using remote sensing techniques
• To study land use patterns in and around the natural forest patches.
• To detect changes in the forest cover.
Methodology
GIS AnalysisScanning • Toposheets, • Paper mapsDigitization of layers • Administrative boundaries (Districts,taluk)• Transport network, (Rail, Roads)• Drainage,waterbodies,• Contours (DEM, Slope, Aspects)• Settlement locations, (Towns,villages)• Global positioning system data
Software used- Arcview 3.3, Arc-info ArcGIS9.1
Methodology
Remote sensing analysisData used
• Land sat TM,(1990) Indian Remote sensing satellite LISS III, (2003)
Techniques• Image enchancement • Radiometric correction• Georeferencing• Supervised classification• Un-supervised classification• Masking• Accuracy assessment• Forest cover change detection
Software used- Erdas imagine 8.7
Methodology
Field survey
• Reconnaissance survey
• Pre-classification ground verification of various class based on the un-supervised classification
• GPS reading for different signature/class
• Post-classification ground verification for various vegetation and land use class
• Collection of photographic evidence for various vegetation classes
Results
Broadly the vegetation types of Eastern ghats are
• Tropical evergreen forests
• Tropical dry deciduous forests
• Southern Mixed dry deciduous forests
• Scrub forests
• Tropical dry evergreen forests
Land use/Land cover
Dry Evergreen Forest
Dry Deciduous Forest
Mixed Dry Deciduous Forest
Thorn Forest
Scrub
Water Bodies
Sandy Bed
Open/Barren/Rocky Exposure/Cloud
Plantation
Waste Land
Settlement
Salt Pan
Shadow
Mangrove
Agriculture
Fallow Land
Total
Area in sq.kms Percentage
2482.52 1.61
14967.61 9.72
18514.09 12.03
11130.89 7.23
14040.11 9.12
2273.25 1.48
705.83 0.46
19580.03 12.72
543.13 0.35
1785.01 1.16
801.71 0.52
22.14 0.01
104.42 0.07
63.80 0.04
43416.89 28.20
23419.10 15.21
153934.29 100
Results
Forest cover of TamilNadu
Area in Sqkm
• Dry evergreen-1318
• Dry deciduous-12069
• Mixed dry deciduous-13553
• Thorn forest-6198
Forest cover of Andhra Pradesh
Area in Sqkm
• Dry evergreen-1164
• Dry deciduous-2898
• Mixed dry deciduous-4961
• Thorn forest-4932
Forest cover of Southern eastern ghats
Area in Sqkm
• Dry evergreen-2482
• Dry deciduous-14967
• Mixed dry deciduous-18514
• Thorn forest-11130
Forest cover change detection map
Area in Sqkm
• Dry evergreen-384
• Dry deciduous-538
• Mixed dry deciduous-1374
• Thorn forest-587
Andhra Pradesh forest cover change
Area in Sqkm
• Dry evergreen-986
• Dry deciduous-2620
• Mixed dry deciduous4230-
• Thorn forest-4811
Tamil Nadu forest cover change
Area in Sqkm
• Dry evergreen-1112
• Dry deciduous-11809
• Mixed dry deciduous-12910
• Thorn forest-5732
Percentage of forest loss
0
2
4
6
8
10
12
14
16
18
Dry evergreen Dry Deciduous Mixed deciduous Thorn
Forest types
Per
cen
tag
e
AP
TN
Thematic layers
Thematic layers
Thematic layers
• Increasing forest loss and habitat fragmentation is serious threat to biodiversity of the landscape.
• Native population of several flora and fauna is declining due to habitat degradation
• Detailed mapping of the fragmented forest patch is required to understand their nature
• Important corridors for mammals such as the Tiger and Elephant are highly threatened.
• Using satellite-based tools, regular monitoring of forest cover is suggested, which can provide valuable inputs for decision makers.
Conclusions
Dry Deciduous
Mixed dry deciduous
Thorn forest
Acknowledgement
• Tamil Nadu Forest Department
• Andhra Pradesh Forest Department
• Public Affairs office, U.S. Embassy, New Delhi
• Worldwide Fund For Nature-India
• Society For Conservation GIS
• Environmental System Research Institute