CLADOCERAN POPULATION DYNAMICS UNDER PREDATION IN TROPICAL POND BASED ON CONTRIBUTION ANALYSIS

摘要

The Daphnids are more vulnerable to its invertebrate rather than vertebrate predation. This research was aimed to study effect of predation on Daphnia species in tropical pond revealed that fish predation decreased fecundity and existence of adults with maximum body size; while invertebrate one leads to decrease in the number and proportion of juveniles. The contribution analysis showed that invertebrate predation was more effective as indicated by ConF-ConA pattern with increase of mean body sized Daphnids and about stable population of ovigerous females. But, ConA being much larger than ConF under fish predation due to increase in ovigerous females with discrete population. We found that both fish and predatory Daphnids affected Daphnia population. However, the invertebrate has largest impact on Daphnia population dynamics in winter season. The predatory fish resulted low predation pressure due to selective feeding of large-sized Daphnids excluded juveniles.