16a_Predation_&_Modeling.pdf

Ecology Week 10 Lecture 16 – Predation 16a: Predation & Modeling  Predator-Prey Interactions -Mathematical modelling 2  Theoretical Ecology - What is goal of modeling interactions? - Predict outcomes, or explain patterns - What is next step?...

Ecology Week 10 Lecture 16 – Predation 16a: Predation & Modeling  Predator-Prey Interactions -Mathematical modelling 2  Theoretical Ecology - What is goal of modeling interactions? - Predict outcomes, or explain patterns - What is next step? - Test for empirical support - Empirical = based on, concerned with, or verifiable by observation or experience rather than theory or pure logic - Theoretical = based on theoretical methods: conceptual models, mathematical models, or computational simulations  Predator-Prey Interactions Population regulation: Predator Bottom-up control? Top-down control? Both? Focal Population Food 4 Spiders and Lizards T. W. Schoener and C. A. Toft, Science 219, 1353 (1983). T. W. Schoener and C. A. Toft, Science 219, 1353 (1983). (Schoener and Toft 1983) ~10 times more orb spiders on islands without predators (lizards) Suggests top-down control (Natural Experiment) 5 Spiders and Lizards Experimental Manipulation: – Introduced spiders to 10 small islands: 5 with lizards, 5 T. W. Schoener and C. A. Toft, Science 219, 1353 (1983). without T. W. Schoener and C. A. Toft, Science 219, 1353 (1983). (Schoener and Spiller 1995) 6 Beetles and Klamath Weed Leaf-feeding beetle (Chrysolina quadrimegina) T. W. Schoener and C. A. Toft, Science 219, 1353 (1983). T. W. Schoener and C. A. Toft, Science 219, 1353 (1983). Klamath weed (Hypericum perforatum) – Toxic to cattle – Introduced to CA in 1900s Example of ‘biological control’ of invasive species 7