Browsing by Author "Iqbal, M.C.M."

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    Can Diversity Indices Reflect the Forest Degradation Status? A Case Study of Hurulu Dry Forest Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2016) Medawatte, W.W.M.A.B.; Iqbal, M.C.M.; Ranwala, S.M.W.
    The degree of dry forest degradation due to anthropogenic disturbance is not yet quantified and this impedes forest restoration interventions and conservation in Sri Lanka. This study investigates selected diversity indices in response to anthropogenic disturbance to assess the severity of disturbance in the Hurulu forest reserve. Three different disturbance regimes (Un-Disturbed [UD], Moderately-Disturbed [MD] and Highly-Disturbed [HD]) were considered based on previous maps of the forest reserve and by conducting a reconnaissance survey. Sixty randomly selected plots (10 m X 20 m) were placed in the above disturbance regimes. In sampling plots, all living trees >1 cm was identified and enumerated by species. Tree species diversity was measured as different diversity and evenness indices such as Shannon's, Simpson's, Berger (reciprocal Berger-Parker diversity), Pielou's evenness and Simpson's evenness index. These indices were transformed to log and compared using one-way ANOVA. There were significant differences among disturbance groups regarding all the indices (P<0.05) excluding Pielou's evenness index (P>0.05). Significantly high mean Berger diversity index value (P<0.05) was observed at UD (3.70±0.01) and lowest at the more disturbed forests, i.e., MD (2.63±0.03) and HD (2.43±0.04). Though mean Shannon and Simpson diversity indices for UD showed significant differences (P<0.05) with HD, they did not show such differences with MD. Mean Simpson's evenness index for UD showed no significant differences (P>0.05) with HD forest. Though mean Shannon and Simpson diversity indices for UD showed significant differences (P<0.05) with HD, but not showed such differences with MD. Mean Simpson's evenness index for UD showed no significant differences (P>0.05) with HD. Though Shannon and Simpson diversity indices are sensitive to high disturbance, best diversity indices to explain differences between Un-disturbed and disturbed forests were Berger diversity index showing its highest value and high sensitivity in those dry forest which are in an undisturbed condition. Key words: Forest degradation, Anthropogenic disturbance, Dry forest
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    Uptake of Heavy Metals by Selected Plant Species
    (Uva Wellassa University of Sri Lanka, 2010) Gunasena, B.R.D.C.; Iqbal, M.C.M.
    As a result of increasing anthropogenic activities, the heavy metal pollution of soil, water, and atmosphere represents a growing environmental problem affecting food quality and human health. Hence, heavy metals should be eliminated from the environment. Several conventional physico-chemical methods are being used to remove heavy metals from the aqueous effluents. But these methods have some disadvantages such as high cost, requirement of expensive equipments, etc. Hence, phytoremediation has been discussed as a cost effective biological remediation technique. During this research work, the heavy metal uptake in two selected plant species i.e. Fimbristylis falcate and Fimbristylis ovate was investigated. Both F. falcate and F. ovate plants were allowed to grow in serpentine soil for two weeks and thereafter, the uptake of Ni and Cr from the soil by the plants was determined. The results showed that F. falcate plants can uptake both Ni and Cr where as F. ovate plants can uptake only Ni, from the serpentine soil in Ussangoda. Hence, from this research it can be concluded that F. falcate could be used to remove both Ni and Cr where as F. ovate could be used to remove only Ni, from the serpentine soil in Ussangoda. Fimbristylis falcate was screened to study the uptake of Ni. The plants were grown hydroponically in a series of Ni concentration where the range was 50 - 350 1.1M of Ni2+. The results showed that the plant can uptake and survive at the range of 250 - 350 µM Ni concentration. Key words: Heavy metals, Phytoremediation, Hyperaccumulation.