An assessment of the solar power plants and their impact on the vegetation in the Poonakary region of Sri Lanka

Abstract

This study aims to assess the impact of a solar power plant on the vegetation in the Poonakary region of Sri Lanka. Data collection primarily relied on a field survey and field observations. A total of 22 transects were used for the study, each measuring 100 m in length and 5 m in width. The extent of the study area is approximately 606.21 ha. Vegetation types, species names, genera, and family details were recorded using a structured data table. Field observations were carried out to assess the potential impact on vegetation in the area. The study was conducted from February 2024 to February 2025. A total of 239 flora species, including 5 endemic species, 24 nationally threatened and 23 near threatened (NT) species, were observed during the field ecological study within the study area. Among the five endemic flora species, one species (Dendrophthoe ligulatus) was listed as nationally Vulnerable (VU) and another (Ampelocissus pheoenicantha) was listed as nationally Near Threatened (NT) according to the national red list 2020 of Sri Lanka. Of the 24 nationally threatened flora species, 7 are listed as nationally Endangered (EN) and 17 species (including 1 endemic) are listed as nationally Vulnerable (VU) species. A few invasive alien flora species were also observed, including Salvinia adnata, Typha angustifolia, Opuntia dillenii, and Lantana camara. The construction of the proposed solar park is expected to cause significant ecological damage by directly impacting diverse and sensitive ecosystems. This includes the destruction of critical vegetation types such as mangroves, salt marshes and seasonally flooded grasslands, which serve as essential habitats for a variety of endemic and migratory species. One of the most immediate threats arises from the clearing of land and vegetation during the construction phase, which will lead to the loss of large habitat areas that support vital ecological functions. These plant communities play a crucial role in carbon sequestration, water purification, and natural flood control. In addition to habitat loss, there is a risk of invasive plant species spreading during construction activities, which can outcompete native vegetation, degrade habitat quality and further threaten biodiversity. The project is proposed in an area recognized for its unique ecological characteristics. While similar species may exist in nearby locations, the remaining natural habitat is extremely limited. Therefore, it cannot be assured that the damage caused can be fully reversed or offset by the surrounding areas. This uncertainty is heightened by the lack of a proper environmental assessment, making it impossible to fully understand or mitigate the long-term impacts of the development. Given these factors, the potential ecological consequences of the solar park cannot be overlooked.