Status of mangroves of north-western part of Indus delta: environmental characteristics and population structure
Mangrove ecosystem of Indus delta is degrading at an alarming rate due tomultiple threats including human activities and the environmental pollution that are themost significant threats among them. This study focuses on the physico-chemicalcharacteristics in the mangroves of north western part of the Indus delta and the effect ofpollution on these characteristics. Particular, attention is paid on population structure ofthe predominant mangrove species Avicennia marina. Comparison was done betweenpolluted and anthropogenically stressed Sites 1, 2, 3 (Rehdri creek) and unpolluted sites4, 5 and 6 (Shah Bunder) were studied. Higher silt fraction was found in Rehdri, whereasgreater clay component was found in Shah Bunder. Soil organic matter ranged between10.9 to 12.4 % in the polluted sites while in the unpolluted sites it ranged between 4.89--8.26%. pH and salinity were both higher in the unpolluted sites at Shah Bunder. Thenutrients and pollutant levels were higher in polluted area, e.g. the maximum TKNrecorded was 7.86±1.47 while it was as low as 0.035±0.01 in the unpolluted locality.BOD and COD were also higher in the creeks of polluted mangroves than in theunpolluted area. The difference in characteristics of the two sites was obvious in clusteranalysis and in the PCA ordination. The growth of the monospecific stands of Avicenniamarina is higher at Rehdri; is due to nutrient dumping from the cattle colony effluent;comparing with Shah Bunder which has a sparse vegetation, lesser tree density andsmaller average DBH, which may be due to lower level of nutrients and/or interspecificcompetition. Greater number of individuals in smaller size classes showed amplerecruitment. Absence of certain size-classes in unpolluted sites could be attributed toillegal harvesting of larger mangrove trees. Types of stresses in both the localities aredifferent and are a cause of concern for the conservationists.
| Main Authors: | , |
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| Format: | article biblioteca |
| Language: | English |
| Published: |
2015
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| Subjects: | Conservation, Environment, Pollution, Mangrove forest, Indus Delta, anthropogenic stresses, pollution., |
| Online Access: | http://hdl.handle.net/1834/40796 |
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| Summary: | Mangrove ecosystem of Indus delta is degrading at an alarming rate due tomultiple threats including human activities and the environmental pollution that are themost significant threats among them. This study focuses on the physico-chemicalcharacteristics in the mangroves of north western part of the Indus delta and the effect ofpollution on these characteristics. Particular, attention is paid on population structure ofthe predominant mangrove species Avicennia marina. Comparison was done betweenpolluted and anthropogenically stressed Sites 1, 2, 3 (Rehdri creek) and unpolluted sites4, 5 and 6 (Shah Bunder) were studied. Higher silt fraction was found in Rehdri, whereasgreater clay component was found in Shah Bunder. Soil organic matter ranged between10.9 to 12.4 % in the polluted sites while in the unpolluted sites it ranged between 4.89--8.26%. pH and salinity were both higher in the unpolluted sites at Shah Bunder. Thenutrients and pollutant levels were higher in polluted area, e.g. the maximum TKNrecorded was 7.86±1.47 while it was as low as 0.035±0.01 in the unpolluted locality.BOD and COD were also higher in the creeks of polluted mangroves than in theunpolluted area. The difference in characteristics of the two sites was obvious in clusteranalysis and in the PCA ordination. The growth of the monospecific stands of Avicenniamarina is higher at Rehdri; is due to nutrient dumping from the cattle colony effluent;comparing with Shah Bunder which has a sparse vegetation, lesser tree density andsmaller average DBH, which may be due to lower level of nutrients and/or interspecificcompetition. Greater number of individuals in smaller size classes showed amplerecruitment. Absence of certain size-classes in unpolluted sites could be attributed toillegal harvesting of larger mangrove trees. Types of stresses in both the localities aredifferent and are a cause of concern for the conservationists. |
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