application of gis and remote sensing technique to assess the status of forest types of the southern...

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