Department of Bio-science

Preliminary Assessment of Seagrass Diversity and Meadow Structure in the Kuchchaveli Coastal Region, Trincomalee, Sri Lanka

Thu, 01 Jan 2026 00:00:00 GMT

Preliminary Assessment of Seagrass Diversity and Meadow Structure in the Kuchchaveli Coastal Region, Trincomalee, Sri Lanka Keerthanaram, T.; Arjunan, K.; Priyanchanaa, S. Seagrass meadows are ecologically important shallow coastal ecosystems that support marine biodiversity, stabilize sediments, enhance coastal productivity, and provide essential nursery habitats for fish and invertebrates. However, limited information is available on the species composition and spatial distribution of seagrass communities along the eastern coast of Sri Lanka. This study presents a preliminary field-based assessment of seagrass cover, species diversity, and meadow structure in the Kuchchaveli coastal region, Trincomalee. Five line-intercept transects were established perpendicular to the shoreline at 250 m intervals, with each transect extending 50 m seaward. Quadrat photographs were used to estimate percentage cover. The overall mean seagrass cover was 46.8 ± 12.4%. Among the recorded species, Oceana serrulata (formerly Cymodocea serrulata) had the highest mean cover (21.6 ± 7.8%), followed by Cymodocea rotundata (16.4 ± 6.2%) and Enhalus acoroides (8.8 ± 4.1%). Based on relative species-cover proportions, the Shannon-Wiener diversity index (H′) was 1.04, and Simpson’s diversity index (1 − D) was 0.63. Species co-occurrence and variation in meadow form indicate spatially heterogeneous habitat conditions, although the roles of sediment type, depth, and hydrodynamics require further investigation. This study establishes baseline ecological information for a poorly studied seagrass habitat on Sri Lanka’s eastern coast. It provides a scientific foundation for long-term monitoring, habitat restoration, and marine spatial planning.

Fishermen’s Perceptions of Dugong (Dugong dugon) Conservation and Seagrass Ecosystems in the Northern Coastal Region of Sri Lanka

Thu, 01 Jan 2026 00:00:00 GMT

Fishermen’s Perceptions of Dugong (Dugong dugon) Conservation and Seagrass Ecosystems in the Northern Coastal Region of Sri Lanka Keerthanaram, T.; Priyanchanaa, S. The dugong (Dugong dugon) is a vulnerable marine mammal that depends primarily on shallow coastal seagrass meadows for food. Although dugongs historically occurred throughout the Gulf of Mannar and Palk Bay, baseline population data for northern Sri Lanka remain limited amid concerns about habitat degradation, incidental capture, hunting, coastal development, and vessel traffic. This study investigated fishermen’s perceptions and local ecological knowledge of dugongs and seagrass ecosystems along the northern coastal belt from Mannar Island to Jaffna Lagoon. A structured questionnaire was administered to respondents from coastal fishing communities using systematic spatial sampling based on 5 km × 5 km coastal grid cells (n = 60). Most respondents were familiar with dugongs (96%), 92% correctly identified the species, and 48% reported observing dugongs while fishing. Nearly three-quarters (72%) perceived that dugong abundance had declined over time. Ecological knowledge of seagrass was high: all respondents recognized seagrass beds, and 95% identified their importance as dugong feeding habitat. Accidental entanglement in fishing gear was the most frequently identified threat (78%), followed by habitat degradation (61%) and disturbance from motorized boat traffic (44%). The conservation-attitude scale showed strong internal reliability (Cronbach’s α = 0.84), with a mean score of 4.1 ± 0.63. Dugong knowledge was positively correlated with conservation attitudes (r = 0.53, p < 0.01) and was the strongest predictor in the regression analysis (p < 0.01). These findings demonstrate that fishermen possess valuable local ecological knowledge that can complement scientific monitoring and support participatory conservation planning and policy development for dugongs and seagrass habitats in northern Sri Lanka.

A Review of Climate Change Impacts, Adaptation, and Mitigation in South Asia.

Sun, 01 Jan 2023 00:00:00 GMT

A Review of Climate Change Impacts, Adaptation, and Mitigation in South Asia. Vijitharan, S. Climate change is a critical global issue, challenging and threatening various sectors in different ways. South Asia is one of the front-line regions to the impacts of climate change. According to the World Bank estimates, in 2021, around 1.9 billion people were in South Asia, including Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka. Therefore, this review aims to assess the impacts of climate change and the existing mitigation and adaptation measures with effectiveness across the South Asian region. We reviewed published reports, journal articles, policy documents, and other grey literature for this study. The findings of this study revealed that total greenhouse gas emissions in South Asia increased from 2.11 TgCO2 in 2000 to 4.16 TgCO2 equivalent in 2019, with an annual rate of change of 5.11%. In total greenhouse gas emissions in 2019, approximately 70% was captured by carbon emissions from 51% in 2000. Among these eight nations, India was the leading greenhouse gas emitter, followed by Pakistan and Bangladesh. South Asia is highly vulnerable to cyclones, floods, erosion, sea level rise, and other natural disasters. Agricultural production is a crucial source of income. Food insecurity was growing due to decreased agricultural yield due to global warming. Not only the agriculture sector, it severely affects other sectors such as health, coastal and marine, energy, water resources, forests, and other ecosystems. The economic cost associated with climate change on a long-term basis is showing an increase by the end of this century. A higher percentage of financial losses can be expected in India. The impacts of climate change can further aggravate water insecurity, the spread of diseases, and biodiversity loss. India, Bangladesh, and the Maldives’ average annual Gross Domestic Product (GDP) growth (%) was nearly equal. However, the CO2 emissions of Bangladesh, Pakistan, and Maldives were 30, 12, and 1,516 times less than India’s, respectively. Noticeably, we found that climate finance and CO2 emissions were strongly and positively correlated, r(6) = .92, p < .05. Similarly, a positive correlation was observed between the average loss due to climate hazards and climate finance, r(6) = .96, p < .01. Therefore, South Asia is witnessing severe effects of climate change, hurting several economic sectors and creating serious obstacles to the area's sustainable development. To lessen these effects and increase resilience to adapt to the changing climate, prompt action is needed in the form of low-carbon development plans, climate-smart agriculture, climate-resilient strategies, Nature-based solutions, sustainable forest and ecosystem management, and strict policies and governance.

Blue Carbon Potential of Mirissanduwa and Kadolgasnelella Conservation Mangrove Forest, Negombo Estuary, Sri Lanka

Wed, 01 Jan 2025 00:00:00 GMT

Blue Carbon Potential of Mirissanduwa and Kadolgasnelella Conservation Mangrove Forest, Negombo Estuary, Sri Lanka Fernando, W.T.S.; Vijitharan, S.; Chathurani, S.H.U.; Jayasundara, J.M.N.M. Mangroves are unique ecosystems thriving in harsh tropical and warm temperate conditions. These ecosystems are crucial for fighting climate change due to their ability to capture and store "blue carbon". The significant carbon stored in mangroves underscores their immense worth as a natural solution for climate change mitigation. Despite mangroves being a recognized source of climate change mitigation, there are limited studies on their role in the Negombo Estuary. The research intends to provide data supporting the protection, restoration, and sustainable management of these vital habitats to directly reduce atmospheric CO2 and enhance climate resilience. Sri Lanka's coastlines host 21 true mangrove species, with significant patches in the Negombo Estuary. The study investigated blue carbon reserves and environmental conditions. Ten 5 m x 5 m plots were randomly sampled to analyse blue carbon. Aboveground biomass (AGB), Belowground biomass (BGB) and Carbon stocks of mangrove biomass were estimated using Diameter at Breast Height (DBH) measurements and allometric equations. A total number of 10 soil samples were randomly collected from each plot to a depth of 30 cm, each using a soil corer. Soil samples were collected to determine pH, salinity, and Total Organic Carbon (TOC). TOC was measured using Loss on Ignition (LOI) method. The total blue carbon was calculated by adding aboveground carbon, belowground carbon and TOC. The study revealed that Rhizophora mucronata was the dominant species. Calculated total aboveground, belowground, TOC and blue carbon stocks were 776.23, 318.71, 438.40 and 1533.34 Mg C ha-1 respectively. Average soil pH was 7.62 ± 0.19 and salinity was 2.90 ± 0.66%. This research enhances our understanding of blue carbon storage in mangroves, underscoring their role in climate change mitigation. Further studies on blue carbon storage and promoting mangrove-based eco tourism are recommended for sustained conservation and economic developmentment.