LAND USE CHANGE MODELLING IN BARAK VALLEY OF NORTHEAST INDIA

Abstract

Barak valley is an area in the north-eastern part of India where traditionally the practice of shifting cultivation has been more prevalent than sedentary agriculture. In the recent past, population growth coupled with the geographic isolation of the area has further aggravated the decline of forest land cover in the area. The region that encompasses the Barak valley, shows varied land covers and has diverse population densities. While some land use and land cover changes are gradual and slow, some can be rapid and fast. Also, many of these changes are dependent on the biophysical and socio-economic drivers of change, including policy inputs. So, there is a need to understand these interactions and how these changes will be affected by the different factors in the near future. This thesis focuses on modelling land use changes in the Kathakal basin of Barak valley, primarily changes in the shifting cultivation patterns, over a period of 1988 to 2005 using an agent-based model after understanding changes in the recent past. Each district is modelled as an agent of change in the agent-based model, 1. to capture the interactions between the various drivers like population changes, infrastructure development and land use practices and 2. to decide on the land resource allocation across the district at the land parcel level including allotment of shifting cultivation regions. The model accounts for both socio-economic as well as geographic factors, like access to infrastructure while making the land use decision on a year-on-year basis. The model considers the need for shifting cultivation land area for both a staple crop – paddy (rice) and a non-staple crop based on the demand against the supply estimated from irrigated and rain-fed cropping regions. While the model has been fine-tuned based on the data till 1997, the simulated model outcome of 2005 is validated against an existing remote sensing derived land use map of the region. The model shows an accuracy of 98% for the test period till 1997 and achieves an overall accuracy of about 94% for 2005 predicted land use pattern. While the aggregated results across the region show good concurrence, the randomness inherent in the choice of the shifting cultivation land limits the ability to predict the precise locations. Further, the thesis will discuss the challenges of different land use conditions prevailing in the two districts and how the model is able to adapt to those in providing a good estimate of the land use changes in a region as diverse as Barak Valley. Based on the model and its applicability to the Barak valley region, the research further explores the impact of various policies on the choice of land use over a period of 30 years, i.e., the land use patterns between 2005 and 2035. Four different scenarios, including a business-as-usual (BAU) scenario were modelled, to highlight how either ecological or economic considerations affects the choice of land use in the two diverse existing land use conditions of the districts of Hailakandi and Mamit. The results show that depending on whether the district is largely rural or urban, has sparse or dense population, and has access to irrigation infrastructure, the land use responses are different. The BAU scenario shows that without intervention of any kind, it is difficult to stop the spread of shifting cultivation due to the land pressures from population growth and the need for increased economic returns from the land. The model shows that infrastructure development and incentivising settled forms of agriculture can have a positive impact on reducing shifting cultivation, though the rate of this change is dependent on both socio-economic and bio-physical conditions of the region.