Assessment of Ecological Disturbance Caused by Flood and Fire in Assam Forests, India, Using MODIS Time Series Data of 2001-2011

Dibyendu Dutta,Akanksha Balha,Libeesh Lukose,Prabir Kumar Das,Pragyan Jain,Wasim Akram

doi:10.5772/intechopen.94282

Abstract

The forest area of Assam State is known for its rich biodiversity. In the present study, the disturbance regime within the Assam forest area caused by periodic flood and forest fire, was assessed using the Moderate Resolution Imaging Spectroradiometer (MODIS) time-series (2001–2011) data. The MODIS Global Disturbance Index (MGDI) images were generated using MODIS derived Enhanced Vegetation Index (EVI) and Land Surface Temperature (LST) images. The temporal intensity of flood and forest fire in sixteen representative forests was analyzed to develop the MGDI based thresholds for detecting the disturbed area. The threshold for the non-instantaneous disturbance, i.e. flood, was found to be 107% whereas it was 111% for instantaneous disturbance, i.e. forest fire. The thresholds were applied on the MGDI images to delineate disturbed caused by flood and fire, separately for each year. The time-series disturbance areas were integrated over the years (2001–2011) to generate the classified disturbance prone maps.

Highlights

The north-eastern state of Assam is known for its rich biodiversity and considered as biological hotspot with many rare and endemic plant and animal species
According to the % disturbed area it was found that the year 2003, 2008, 2009 and 2010 were the most disturbed years caused by river flood in comparison to rest of the years
The ecological disturbance regime of the Assam forest area was assessed using Global Disturbance Index derived from the time-series Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) and Land Surface Temperature (LST) data

Summary

Introduction

The north-eastern state of Assam is known for its rich biodiversity and considered as biological hotspot with many rare and endemic plant and animal species. Km geographical area of the state, the forest area covers around 24.58% area. The moderate dense forests areas which are mainly extended through districts of Karbi Anglong, NC Hills, Cachar, Karimganj, Hailakandi, northern part of Kokrajhar, Bongaigaon and southern part of Kamrup, Tinsukia, are vulnerable to frequent flood incidents. The Brahmaputra River and its tributaries, flowing from north-east to south-west, are the mainly responsible for the periodic floods in Assam State. The incidence of forest fires in the deciduous forests during summer season, i.e. March to April, causing a wide spread disturbance in Remote Sensing the forest eco-system. Assam State has 5 National Parks and 16 Wildlife Sanctuaries under protected area (PA) network and constituting 4.98% of the geographical area. The protected areas can act as benchmark for differentiating the ecological disturbance from the natural fluctuation [1]. Regular monitoring of PA’s is crucial for detecting the rapid changes in functional attributes as well as to identify areas that need to adapt or modify to meet the challenges posed by global warming [2]

Methods

Results

Conclusion