ZOOPLANKTON DIVERSITY DIFFERENCE IN TROPICAL ECOSYSTEM: A STUDY FROM THE MEGHNA RIVER ESTUARY, BANGLADESH

Abstract

To know about the trophic level relationship among the zooplankton, phytoplankton, and fish species, it is important to know about the zooplankton diversity difference through ecosystems. The present study was conducted to assess the zooplankton diversity difference of the Meghna river estuary in twenty sites in the month of July 2016. It also aims at identification of the area where higher disturbance occurs and species displacement risk is high, and also the area where species recruitment is high. Markov Chain model of ecological communities was utilized to explore general process of diversity differences of zooplankton between estuarine system and riverine system. Ten species of zooplankton were identified from sampling sites to run the model. The findings showed that estuary has high diversity where displacement risk was also high and river had low diversity and species displacement risk was also low. As predicted by diversity theory, invasion rate curve for estuary was more skewed than river and proportional abundance of species in estuary was higher than river. The model also found that disturbance was substantially higher on river than estuary. Trade-off between interspecific displacement and disturbance risk in either ecosystems among species were positive. The average intransitivity in transitions among zooplankton tended to be lower in estuary. The model further indicates that higher intransitivities and species disturbance declines species diversity when higher recruitment and interspecific replacement increase species diversity. This study will provide knowledge about zooplankton diversity differences between river and estuary which can help to undertake a proper management strategy in the Meghna river estuary