Response of predators to prey abundance: separating the effects of prey density and patch size
Författare
Summary, in English
We tested the relative and combined effects of prey density and patch size on the functional response (number of attacks per unit time and duration of attacks) of a predatory reef fish (Cheilodactylus nigripes (Richardson)) to their invertebrate prey. Fish attacked prey at a greater rate and for longer time in large than small patches of prey, but large patches had naturally greater densities of prey. We isolated the effects of patch size and prey density by reducing the density of prey in larger patches to equal that of small patches; thereby controlling for prey density. We found that the intensity at which fish attacked prey (combination of attack rate and duration) was primarily a response to prey density rather than the size of patch they occupied. However, there was evidence that fish spent more time foraging in larger than smaller patches independent of prey density; presumably because of the greater total number of prey available. These experimental observations suggest that fish can distinguish between different notions of prey abundance in ways that enhance their rate of consumption. Although fish may feed in a density dependent manner, a critical issue is whether their rate of consumption outstrips the rate of increase in prey abundance to cause density dependent mortality of prey.
Publiceringsår
2002
Språk
Engelska
Sidor
61-71
Publikation/Tidskrift/Serie
Journal of Experimental Marine Biology and Ecology
Volym
273
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Biological Sciences
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0022-0981