Community Effects of the Non-Indigenous Aquatic Plant Water Hyacinth (Eichhornia crassipes) in the Sacramento/San Joaquin Delta, California
Abstract
Biological invaders are widespread and can alter population dynamics and community structure of native ecosystems. Substantial habitat alteration by nonindigenous
species can additionally affect the surrounding community. Aquatic plants are particularly invasive, especially in areas that are modified by humans. Water
hyacinth (Eichhornia crassipes) is a floating aquatic plant that is non-indigenous to the
Sacramento/San Joaquin Delta, California. A common native that functionally occupies similar habitats as hyacinth is pennywort (Hydrocotyle umbellata). Based on the utilization of such habitats
by invertebrates and fish, my main scientific question was: Has hyacinth modified the
invertebrate assemblage structure and fish-invertebrate food web as compared to
pennywort? To assess this, I sampled invertebrates in hyacinth and pennywort and
analyzed fish diets in the surrounding area at three sites in the Delta during 1998 and 1999. I also took measurements of leaf density, root structure, dissolved oxygen and
temperature. Ecological differences between hyacinth and pennywort were linked to habitat
architecture. Coupled with the management challenges of hyacinth, its ecological
modifications make it an even more influential invader.
Collections
- Fisheries [238]