Water hyacinth in Lake Victoria: Why did it vanish so quickly and will it return?

摘要: Abstract Water hyacinth has been a cause of great concern in terms environmental and socio-economic impacts within Lake Victoria. In the late 1990s however it rapidly disappeared but since causes are unknown its possible return cannot be predicted. Growth chamber laboratory experiments investigating CO2 assimilation growth rate found that different phenotypic, density-acclimated, forms water behaved differently. PI-curves changes biomass revealed short bulbous (SB) took up more increased quicker than tall non-bulbous (TN) forms. This allows two to flourish niches. One, SB form, as colonising opportunist other taller plant attempts avoid self-shading dense mats. Light is an important limiting factor growth. becomes non-limiting uptake at PAR ≈2000 μE m−2 s−1. Victoria this light level occurs for about 6 h around midday. Plant thus limited most day can even midday during cloudy weather. Although weevils likely played role rapid disappearance hyacinth, demise was too synchronous large lake solely responsible. The cloudy, wet El Nino weather 1997/1998 probably major contributory poor led reduction lake-wide. Currently improved climate, ever increasing supply nutrients potentially unstable weevil population will allow resurgence aggressive weed.