EXAMINATION OF ENVIRONMENTAL FACTORS AFFECTING THE LARGE SPATIAL DISTRIBUTION OF EGERIA DENSA

Abstract

 The overgrowth of Egeria densa is a major issue in the Gonokawa River. It is necessary to identify the environmental factors negatively affecting E. densa in the river in order to develop the management strategies for eradicating the nonnative aquatic plant. In this study, we quantified the coverage of E. densa with UAV and analyzed the relationships between the coverage and environmental factors on preflood seasons using simple linear regression and generalized linear model. Our results indicated that the coverage was significantly and negatively related to the coefficient of variation of the river discharge in the preflood seasons, suggesting that the river discharge fluctuations could suppress the overgrowth of E. densa in the river.