Effects of Urbanization on spatial distribution,threats and conservation of freshwater fishes in Mahaoya,Sri Lanka
Deparment Of Zoology,University Of Peradeniya,Peradeniya,Sri Lanka
Arguably ,freshwater fish are the most vulnerable taxonomic group as most of the threatened and endemic fish are found in streams that are lying outside the Protected Area.Therefore these habitats are highly susceptible to various threats such as waste accumulations,expanding agriculture,large and small scale hydro projects,exposure to chemical pollutants including agrochemicals and sedimentation.
Four study sites was selected in Mawanellatown,Aranayaka,Rambukkana and Kondeniya at different urbanization levels.eight months of study period.for each study site 12 plots,each was 10meters in length.also the aquatic temperature,pH,Total dissolved solids,Conductivity,dissolved oxygen,Nitrate,Phosphate,Calcium were measured for each plot.A questionnaire survey on urbanization level was also done
Total number of thirty fishes were recorded during the study.Out of them 20% were endangered.Species diversity and abundance were negatively (P<0.001) correlated with TDS,Conductivity, NO3,PO4-3 and CaCO3 levels.While they were positively(P<0.001)correlated with Oxygen.species diversity and abundance were reduced along the urbanization gradient from Rambukkana,Aranayaka,Kondeniya to Mawanellatown.
These results clearly states that there is a negative effect of water pollution associated with urbanization.The increasing human population puts pressure on water sources,causing increased extraction,industrial and agricultural waste accumulation and other human pollutants.Community based conservation plans and education on controlling water pollution is really needed to address this matter.