Power11b_DisturbanceFoodChainNotes - Disturbance and food...

Info icon This preview shows pages 1–2. Sign up to view the full content.

1 Disturbance and food chain length 1. Strength (sometimes the sign) of food web interactions are context dependent. 2. Disturbance can lengthen food chains by resetting lower trophic levels to early successional states dominated by more edible taxa. 3. Diet doesn’t predict dynamics. Top down control pathways can differ from energy flow bottom up pathways in the same food web. 2 4 levels: barren 3 levels: green, and nitrogen limited (Hairston et al. 1960 Fretwell 1977) 3 1990,1991: Roach, Steelhead, Both, Neither (6 replicates) Algae collapsed to detritus in all treatments ! 4 Big armored caddisfly grazer: Dicosmoecus gilvipes ( indiv / sq. m) flood: 0-1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: drought: 40-90 Drought: no scouring winter floods 5 D i c o s m e u-+ Wootton, Parker and Power 1996, Science Experimental Treatments (N = 6): Dicosmoecus (+, -) x Steelhead (+, -) 6 6 6 6 Steelhead: + -6 Dicosmoecus No No Dicosmoecus Dicosmoecus 7 Defended (armored or sessile) grazers dominate downstream from dams or diversions, where flow is artificially regulated 8 Natural Disturbance vs Artificial Regulation Flood: Edible grazers Drought: Inedible grazers 9 Diet doesn’t predict dynamics!! Top down cascade through four trophic levels Bottom up energy flow through three trophic levels...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern