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On a worldwide scale, land use and land cover changes (LULCC) is a major driver of global change and biodiversity erosion. This study aims to monitor at the scale of Sri Lanka, LULCC and vegetation dynamics, to identify the main changes and their drivers. It places emphasis on multiscale geospatial monitoring with satellite data but also mobilises the interdisciplinary knowledge of a research programme. First, national scale data allows the identification of major changes with the MODIS NDVI dataset using Mann-Kendall tests and time profile analysis. A second local scale was mobilised with a systematic diachronic visual interpretation of high-resolution images on Google Earth. The third step, a macro-regional scale focus on the South and East coasts, used LANDSAT imagery (Stacked K-means) verified by field studies (botanical and vegetation analysis, and interviews). About 92.5% of the island of Sri Lanka is stable or presents no significant trends in the vegetation cover. 5% show a significant positive (greening) trend between 2000 and 2020 around the Puttalam lagoon, west of the Samanalawewa Reservoir, in the Udawalawe National Park, east and north of Ella, and the Nuwaragala Forest Reserve. Only about 2.5% (165,000 ha) of the Island shows a negative significant trend mainly in the periphery of Colombo and Trincomalee. The first driver is a set of national planning decisions in terms of infrastructure development (including urban growth, housing programmes and agricultural fields, and the management of protected areas). The second driver comes under rural dynamics with increasing tree density in rural landscapes over the Uva Province. Infrastructure development initiated by the state, creates both underlying conditions for other activities and negative impacts on coastal ecosystems, such as degradation of wetlands (including protected areas). [ABSTRACT FROM AUTHOR]

Sea-level rise is a key component of many climate change scenarios. Such increases are expected to cause greater coastal inundation by seawater, reduce the depth of the freshwater-saline water lens and have a range of consequences for coastal ecosystems. Soil salinity determines the distribution patterns of coastal vegetation across a sea-to-land gradient, and sea-level rise would be expected to alter these distributions. Our study done along the east coast of Sri Lanka shows that soil salinity decreases predictably from sea to land, varying between 21‰ and 30‰ over a distance of 50 m from the mean high water springs level. Soil salinity also showed declines with increasing soil depth (0, 10, 50 cm) although this was marginally non-significant. The emergence of terrestrial vegetation coincided with a cross-shore ecotone where the soil salinity approached 0‰. Our predictions suggest that if the mean sea-level were to increase by 1 m in the Batticaloa region (Sri Lanka), this would cause landward communities to be inundated with brackish water at various depths. The present permanent coastal vegetation front would likely shift landward by 30-45 m under scenarios involving a 1 m increase in sea level. Sea-level rise and its consequences could result in a variety of changes to coastal vegetation such as altered physiognomy and diversity, colonization of new territory, expansion of salt-tolerant species such as mangroves and saltmarsh and will therefore greatly influence adaptive management and future planning. This article is part of the theme issue 'Developing resilient energy systems'.