Journal of the Marine Biological Association of India

Temporal changes in land cover of mangroves and allied biotopes in Abdasa, Kachchh district, Gujarat, India

Volume 65 Issue 2

R. Madhavan Unny, K. Karthika and S. Paulsamy

10.6024/jmbai.2023.65.2.2409-01

Abstract

The present work investigates the temporal land cover changes in mangroves and two other allied biotopes, namely, mudflats and “other vegetation”, in the Abdasa taluka of the Northwestern coast of Gujarat, India, through LISS IV satellite imageries with a resolution of 5.8 m. Satellite images from four different years (2007, 2014, 2017, and 2021) procured from the National Remote Sensing Agency, Hyderabad, India, were used for this purpose. Image analysis suggested different levels of geomorphologic change in these three coastal biotopes in the four years of analysis. Mangrove extent increased by a maximum of 17.46 km2 (50.7%) between 2007 and 2014, although this expansion was only minor between 2014 and 2017, with an increase of 1.59 km2 (3.06%). Subsequently, between 2017 and 2021, the mangrove extent decreased by 15.01 km2 (28.06%). Altogether, mangroves in Abdasa had a net increase of 4.04 km2 from 34.4 to 38.49 km2 throughout the course of the 14-year assessment between 2007 and 2021, representing an increase in the area of 11.7%. Most of the mangrove increase was on the northwest coast of Abdasa near the village of Golay. Mudflats, on the other hand, experienced a very slight decline of 0.4 km2 from 2007 to 2014, from 202.4 km2 to 202 km2 . Subsequently, between 2014 and 2017, they dramatically increased by 69.82 km2 before experiencing another decline of 165.92 km2 between 2017 and 2021. As compared to mangroves and mudflats, the third land cover category, “Other Vegetation,” underwent only a marginal change in its land cover during these 14 years of study, with a net increase of 1.74 km2 from 17.6 to 19.34 km2 , accounting for a 9.88% increase in its area. This dynamic shift in the study area’s coastal land cover is caused by a complex interaction of physical, chemical, and biological processes. It is suggested that the ongoing plantation effort, the favourable effects of rising sea levels, altered near-shore currents and sediment dynamics were the primary causes of the net growth of the 4.04 km2 in the Abdasa mangroves during  the period of study. This study signifies the importance of investigating changes in the mangrove extent at regular intervals at a local scale, which could contribute to the conservation and protection of this vital ecosystem, especially in the light of climate change-associated sea level rise, coastal erosion, and industrial development.

Keywords

Areal extent, GIS, Avicennia marina, mudflat, other vegetation

Date : 17-11-2023