Exploitation by Introduced Species
28 29 Brown Tree Snake (Boiga irregularis) Introduced to Guam (mid-1940s) 31
Myiagra freycineti (Guam flycatcher) Gallicolumba xanthonura White-throated ground-dove Zosterops conspicillatus ** Bridled white-eye Acrocephalus luscinia Nightingale reed-warbler Rhipidura rufifrons * Rufous fantail Ptilinopus roseicapilla Mariana fruit-dove Myzomela cardinalis Cardinal honeyeater Halcyon cinnamomina ** Micronesian kingfisher Nine of Eleven Native Forest Birds in Guam EXTIRPATED/EXTINCT 30
SUCCESS OF SPECIES INTRODUCED OUTSIDE OF NATURAL GEOGRAPHIC DISTRIBUTION No Coevolved Interspecific Competitors No Coevolved Herbivores No Coevolved Parasites No Coevolved Pathogens
Predator-Prey Dynamics
Sunspot Hypothesis (Elton 1924) What Controls Snowshoe Hare Population Fluctuations? Predator Hypotheses Food Supply/Quality Hypotheses Overpopulation Hypotheses
TEASING OUT THE INDIVIDUAL EFFECTS: CONTROLLED EXPERIMENT 27 Test for Effects of Predators, Plant Food Supply, Quality
ControlsSupplemental Food Fertilizer Electric Fence / Supplemental Food Electrical Fence Krebs et al YEAR STUDY TEASING OUT THE INDIVIDUAL EFFECTS: CONTROLLED EXPERIMENT
Fig in Molles 2006 TEASING OUT THE INDIVIDUAL EFFECTS: CONTROLLED EXPERIMENT
Underlying Processes: Predator – Prey Dynamics Alfred Lotka (1925) Vito Volterra (1926)
dN h /dt = r h N h – pN h N p Modeling Population Change: Host (= Prey) r h = p = N h = N p =
dN p /dt = c p N h N p -d p N p Modeling Population Change: Predator c p = N h = N p = d p =
Fig in Molles 2006
2 Predator – Prey Oscillation in the Laboratory?
Fig in Molles 2006 Bean Weevil Parasitoid Wasp Utida 1957 Predator – Prey Oscillation in the Laboratory?
Predator – Prey Relationships in the Lab (Paramecium – Didinium) G. Gause (1935) Predator: Didinium Prey: Paramecium
Predator – Prey Relationships in the Lab (Paramecium – Didinium) Fig in Molles 2006 Experiment 1
PreyPredator Fig in Molles 2006 Trial 2 Predator – Prey Relationships in the Lab: Refuges (Paramecium – Didinium) Add a Refuge: Sediment
Predator – Prey Relationships in the Lab: Restock Predators (Paramecium – Didinium) Fig in Molles 2006 Prey Predator Trial 3 Restock the Predator
10 Predatory Mite Can Crawl Feeds on Six-Spotted Mite Six-Spotted Mite Feeds on Oranges Can Crawl or “Balloon” via Silk Strand Predator – Prey Relationships in the Lab (Predatory Mite / Six-Spotted Mite)
Predator – Prey Relationships in the Lab (Predatory Mite / Six-Spotted Mite) Fig in Cain et al. 2008
Huffaker (1958) Predator – Prey Relationships in the Lab: Refuges and Complexity (Predatory Mite / Six-Spotted Mite) Fig in Cain et al Additional Complexity Widely Spaced Oranges Intervening Vaseline Strips Posts Inserted on Some Oranges to Facilitate Ballooning
9
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_DFO2_l.jpg /short~eared~owl~607.jpg snowshoe-hare.jpg 19
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