|Strong top-down control in southern California kelp forest ecosystems|
Halpern, B.S.; Cottenie, K.; Broitman, B.R. (2006). Strong top-down control in southern California kelp forest ecosystems. Science (Wash.) 312(5777): 1230-1232
In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075, more
Ecosystems; Food webs; Kelps; Marine
|Authors|| || Top |
- Halpern, B.S.
- Cottenie, K.
- Broitman, B.R.
Global-scale changes in anthropogenic nutrient input into marine ecosystems via terrestrial runoff, coupled with widespread predator removal via fishing, have created greater urgency for understanding the relative role of top-down versus bottom-up control of food web dynamics. Yet recent large-scale studies of community regulation in marine ecosystems have shown dramatically different results that leave this issue largely unresolved. We combined a multiyear, large-scale data set of species abundances for 46 species in kelp forests from the California Channel Islands with satellite-derived primary production and found that top-down control explains 7- to 10-fold more of the variance in abundance of bottom and mid-trophic levels than does bottom-up control. This top-down control was propagated via a variety of species-level direct and indirect responses to predator abundance. Management of top-down influences such as fishing may be more important in coastal marine ecosystems, particularly in kelp forest systems, than is commonly thought.