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Explore documented actions and consequences on various scales to understand habitat linkages in populations. Concepts like optimal foraging, selfish cow theory, and plasticity are evaluated. Use CARMA data for investigation.
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SYNTHESIS APPROACHFOUR EXAMPLES CARMA 6 1-2 pm 4th December 2009 CHAIR: Bob White
HABITAT LINKAGES TO THE INDIVIDUAL AND POPULATION • Scale of documented actions (both spatial & temporal) and consequences must be explicitly identified • This allows assessment of potential cross-scale [and cross-class] cumulative effects of foraging, predation, and pathogen exposure • 1-Plant parts within plant species • 2-Plant species within habitat patches • 3-Habitat patch within concentrated use areas • 4-Concentrated use areas within seasonal range • 5-Seasonal range within annual range • 6-Annual range within herd range • 7-Herd ranges within species • 8-[Sub] Species distributions on earth NUTRIENT INTAKE NUTRIENT INTAKE PREDATION RISK PATHOGEN EXPOSURE
SCALING UP FROM THE INDIVIDUAL In order to interpret observed population distribution and response, and to predict responses in relation to assumed climate and anthropogenic effects, a number of concepts that have relevance for Rangifer linking the individual to the population need evaluation: • Optimum foraging: theory used to link diet and habitat use to meeting energy and nutrient requirements • Selfish cow: a theory that accounts for the distribution of maternal investment of energy and protein that has relevance for offspring growth and survival and the occurrence of breeding pauses • Plasticity and constraint: examines the ability of individuals and populations to respond (be plastic) to environmental variability within evolved behavioral, physiological or genetic constraints. An inability to respond has been coined as a “trophic mismatch” • Capital versus Income breeders: the evolved strategy of allocating energy and protein to embryos from females body reserves (capital) or diet (income) which conveys selective advantage; in Rangifer the application would be (is?) exemplified at the subspecies level. • Pathogens and body condition: the chicken and egg: identification of conditions under which pathogens insert a preemptive versus compensatory response of individuals and components of the population vital rates (mortality, pregnancy) USE OF MODELS AS WELL AS CARMA DATA SETS TO INVESTIGATE APPLICABILITY AND/OR MECHANISM RELATIVE TO CONCEPTS
LINKAGES: POPULATIONS TO FORAGE AND WEATHER (Joly, Stephens, White) INDIVIDUALS TO POPULATIONS (Barboza, White) LINKAGES & EXTRAPOLATION: PATHOGENS- BEYOND INVENTORY (Kutz) GLOBAL CHANGE (Kofinas) EXAMPLES AND PROCESS
Example 2: Linking individuals to the population – some practical examples • Barboza- • White- Decision tree for weaning and conception • Body composition • Milk composition
“SELFISH COW” HEAVIEST CALVES OF THE COHORT IN MARCH
REINDEER CALF GROWTH RATE White & Luick 1976 * N.S. * * Control Period1 Period 2
COW BODYWEIGHT GAIN: “SELFISH” COW? White & Luick 1976 PERIOD 1 PERIOD 2 CONTROL
? HEAVIEST CALVES OF THE COHORT IN MARCH
HEAVIEST CALVES OF THE COHORT IN MARCH MILK COMPOSITION = PEAK LACTATION