Spatio-temporal comparisons of intertidal macrofaunal communities along anthropogenically influenced Mandvi coast, Gulf of Kachchh, India

Natural and human disturbances can affect population and community assemblages in complex ways. In the present study, we tried to investigate the intertidal assemblage at three distinct but spatially close located sites (Kathda, Mandvi, and Modhva) along the Kachchh coast (Northern Gulf of Kachchh). The efforts were also made to corelate anthropogenic effects with intertidal assemblage. Mandvi served as an anthropogenically active site whereas rest two remained as a control sites with minimal disturbance. Replicate quadrate samples on the fixed transect lines and wet biomass analyses were carried for three seasons. Total  43 species, viz. mollusc (21), crustaceans (12), Polychetes (7), Nemertea (01), fishes (02) were recorded. Overall population densities ranged from 0 to 999 ind./m2 ; biomass  0 to 899 gm/m2, and the Simpson evenness index  0.15 to 0.89. Season wise, high abundance, and diversity were observed during winter with the highest densities of Umbonium vestiarium and Cerethidia cingulata. High densities were observed at Modhva followed by Kathda and Mandvi. Relatively lower intertidal macrofaunal diversity and density were clearly observed at Mandvi which had high tourism pressure. Such comparative data can serve as vital baseline and can be a part of future monitoring process especially at anthropogenic influenced sites.   Natural and human disturbances can affect population and community assemblages in complex ways. In the present study, we tried to investigate the intertidal assemblage at three distinct but spatially close located sites (Kathda, Mandvi, and Modhva) along the Kachchh coast (Northern Gulf of Kachchh). The efforts were also made to corelate anthropogenic effects with intertidal assemblage. Mandvi served as an anthropogenically active site whereas rest two remained as a control sites with minimal disturbance. Replicate quadrate samples on the fixed transect lines and wet biomass analyses were carried for three seasons. Total  43 species, viz. mollusc (21), crustaceans (12), Polychetes (7), Nemertea (01), fishes (02) were recorded. Overall population densities ranged from 0 to 999 ind./m2 ; biomass  0 to 899 gm/m2, and the Simpson evenness index  0.15 to 0.89. Season wise, high abundance, and diversity were observed during winter with the highest densities of Umbonium vestiarium and Cerethidia cingulata. High densities were observed at Modhva followed by Kathda and Mandvi. Relatively lower intertidal macrofaunal diversity and density were clearly observed at Mandvi which had high tourism pressure. Such comparative data can serve as vital baseline and can be a part of future monitoring process especially at anthropogenic influenced sites.