Effect of air and noise pollution on species diversity and population density of forest birds at Lalpahari, West Bengal, India

The Rajmahal-type quality stones for building purposes are found abundantly in Birbhum district, West Bengal, India, where stone mining and crushing have become the main industrial activity. Although crusher dust is injurious to health, demand for crushed stone is ever-increasing as a result of rapid infrastructural growth in the country. Most of the crusher units at Rampurhat are situated along the roadways adjacent to forest under Tumboni Beat of Rampurhat Range of Birbhum Forest Division. Excessive load of air pollution in this area has led to degradation of this forest. The status of the ambient air and noise level was evaluated. The effect of air and noise pollution on abundance and variability of birds in this forest have been compared to an almost non-polluted forest of the same bio-geographic zone. Both species diversity and population density of birds were found to decrease in the polluted forest, especially in the areas adjacent to crushers. For comparing the pollution status of two different forest sites and for establishing whether the density of birds have any correlation between the sites, the Student's t-test and the chi-square test were applied respectively. Most of the results proved to be significant.

► Two tropical deciduous forests of same biogeographic zone were selected for bird-counting. ► Air and noise pollution levels were reported to be very high. ► The stone crusher industry sector in the vicinity degraded air quality of one forest. ► Bird-counts in polluted forest were lower in all respects. ► Thus, density and diversity of forest birds are regulated by ambient air quality.