Browsing by Author "Kadupitiya, H.K."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Evaluating the Impacts of Land Use Land Cover Changes on Agro-biodiversity of Kandyan Home Gardens
    (Uva Wellassa University of Sri Lanka, 2016) Abeysinghe, A.M.N.S.K.; Alwis, L.M.H.R.; Rathnayake, R.M.C.W.M.; Kadupitiya, H.K.
    Kandyan Home Gardens are multi-species traditional agro-forestry systems which conserve biodiversity. Land Use / Land Cover changes adversely affect on biodiversity in Kandyan Home Gardens. Land Use / Land Cover changes in the Kandy district were analyzed using Remote Sensing and GIS techniques. Landsat images of year 2000 and 2015 were used for the study. Supervised classification technique was used to identify different Land Use / Land Cover classes and Land Use / Land Cover change maps for year 2000 and 2015 were prepared. Normalized Difference Vegetation Index (NDVI) maps were prepared for year 2000 and 2015. Least square regression technique was used to rectify the climatic influences in satellite images. By obtaining the percentage NDVI change between 2000 and 2015, three Land Use / Land Cover change categories were identified; less changed, moderately changed and highly changed. Agro-biodiversity in Kandyan Home Gardens was evaluated through field investigations in 90 home gardens in Ambathenna, Pilimathalawa, and Gampola. The Land Use / Land Cover change category which each Kandyan Home Garden belonged to was identified using Global Positioning System. Species Richness, Shannon-Weiner index and Simpson Diversity Index were used to assess the agro-biodiversity. Land holding size in majority of home gardens was between 0.01 to 0.758 ha. Trees and root and tuber crops consisted of 88 species and 45 plant families were identified. Less changed area and moderately changed area had similar Species Richness and Shannon-Weiner values for diversity, but evenness of abundant species was higher in moderately changed area. Thus, agro-biodiversity in moderately changed area was high. Twenty seven species were perceived as threatened or lost from Kandyan Home Gardens. The study suggests the need of linking tree conservation programme with home gardens. A proper investigation has to be carried out to identify the threatened varieties. Keywords: Agra-biodiversity, Kandyan Home Gardens, Land Use / Land Cover change, GIS and Remote Sensing
  • No Thumbnail Available
    Item
    Soil Organic Carbon and Interdependencies among Soil Physio-Chemical Parameters of Mangrove Dominated Ecosystem at Palakaimunai in Mannar Region, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2021) Dissanayake, D.D.M.O.; Jayasinghe, J.A.V.R.; Perera, G.A.D.; Kadupitiya, H.K.; Seneweera, S.; Ratnayake, R.R.
    Palakaimunai, positioned at North Western coast of Sri Lanka, has been shaped and influenced by oceanic, terrestrial and anthropogenic activities to varying extent. The natural vegetation in this deltatic system is dominated with mangroves with intermittently spreading saltmarsh patches at the foreground and littoral woodland species at the back. The extent which the mangroves in such seasonally dry tropical climates would provide sediment-grounds for soil carbon and other nutrients is yet to be revealed. Therefore, spatial variation of soil carbon and carbon fractions, and the associations of these to available nutrients in Palakaimunai mangals were examined in this study. Stratified random sampling adhering to 10 m × 10 m grids based on ArcGIS were laid and soil sampling (n=30) was done from the layer of 0-15 cm from surface. Samples were analyzed for available nitrate, phosphate and ammonium, microbial biomass carbon (MBC), permanganate oxidizable carbon (POC), water soluble carbon (WSC) and soil organic carbon (SOC), soil macro and micro nutrient cations. Principal component (PC) analysis and agglomerative hierarchical clustering based on geometric positioning under PCs revealed five clusters indendogram, despite there was a high spatial heterogeneity examined soil parameters over the area. Interdependencies were unreciprocated among pH (+) to SOC (-) and WSC (-) and ammonium (-) and zinc (-) to MBC (+). The samples in the clusters with the highest mean SOC content of 11.3%- 14.0% and was associated with low MBC (0.005% ± 0.007) , high POC (712.23 ± 6.97 mg/kg), high WSC (0. 15% - 0.16%) and high ammonium (14.2 ± 8.5 mg/kg) contents. Nevertheless, the samples in the cluster with the lowest SOC content of 1.99 ± 1.54 was found to be associated with the highest availability of nitrate (2.90 ± 0.78) and lowest of phosphate (14.98 ± 6.02 mg/kg) contents. These highest SOC contents were recorded at proximate substratum with Avicenia and Rhizophora species and within frequently saturated substratum. Simultaneously, low MBC content was related with the above prevailing aneroxic condition. Thereby, generalization over in-site SOC may not verify the carbon sink potentiality thus varied by geomorphological traits. Keywords: Blue carbon ecosystems; MBC; WSC; Cluster analysis; SOC