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The influence of The influence of dispersal & dispersal &
seasonality on lynx seasonality on lynx dynamics in W. dynamics in W.
CanadaCanada
Gabriela Yates & Mark Boyce
University of Alberta
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Cycle breakdown- localized Cycle breakdown- localized areasareas
Lynx harvest in northern Alberta Lynx harvest in northern Alberta (Wood (Wood Buffalo Nat. Park)Buffalo Nat. Park) compared to Nordegg, compared to Nordegg, Alberta site Alberta site (Central Eastern Slopes).(Central Eastern Slopes).
Boyce et al. 2005. Biological Conservation 126: 395.Boyce et al. 2005. Biological Conservation 126: 395.
Mullen. 2006. M.S. Thesis, University of Alberta.Mullen. 2006. M.S. Thesis, University of Alberta.
AB & BC have significant cycles at a provincial scale
Results of spectral analysis of lynx population timeseries from harvest data
Murray et al. In press. Journal of Wildlife Management.
Cycle breakdown- Cycle breakdown- provincial scaleprovincial scale
Border States do NOT have significant cycles
Results of spectral analysis of lynx population timeseries from harvest data
Murray et al. In press. Journal of Wildlife Management.
Cycle breakdown- Cycle breakdown- provincial scaleprovincial scale
Biological mechanismsBiological mechanismsaffecting southern cyclesaffecting southern cycles
Predator dispersalPredator dispersal Pulse from epicenter (Pulse from epicenter (Ranta et al. 1997)Ranta et al. 1997)
Southern prey densities too low to Southern prey densities too low to
support cyclic dynamics support cyclic dynamics
(Steury & Murray 2004)(Steury & Murray 2004) Population sinkPopulation sink Immigration pulse from the core Immigration pulse from the core
(McKelvey et al. 2000) (McKelvey et al. 2000)
Hypotheses 1: Southern dynamics & Hypotheses 1: Southern dynamics & persistence dependent on dispersalpersistence dependent on dispersal
Biological mechanismsBiological mechanismsaffecting southern cyclesaffecting southern cycles
Climate - seasonalityClimate - seasonality Synchrony vs. asynchrony Synchrony vs. asynchrony
(Stenseth et al. 1999,2004)(Stenseth et al. 1999,2004) NAONAO East-west (provincial statistics)East-west (provincial statistics)
Sunspot driven weather Sunspot driven weather (Sinclair et al. 1993, Sinclair & (Sinclair et al. 1993, Sinclair & Gosline 1997)Gosline 1997)
Doesn’t explain eastern asynchrony (affected by NAO)Doesn’t explain eastern asynchrony (affected by NAO) Seasonality produces phase locking Seasonality produces phase locking (King & Schaffer (King & Schaffer
2001)2001)
Hypothesis 2: Weakened seasonality Hypothesis 2: Weakened seasonality reduces seasonal forcing sustaining multi-reduces seasonal forcing sustaining multi-year oscillatoryear oscillator
Research questionResearch question
Are changes in lynx dynamics Are changes in lynx dynamics related to related to .. human induced human induced change?change? Barriers to predator dispersal Barriers to predator dispersal
Fragmentation due to Fragmentation due to industrial/urban developmentindustrial/urban development
Weakened seasonalityWeakened seasonality Temperatures of the boreal Temperatures of the boreal
increasing since 70sincreasing since 70s Climate change may have Climate change may have
widespread consequenceswidespread consequences
Research objectivesResearch objectives
Evaluate dispersal vs. seasonal-forcing Evaluate dispersal vs. seasonal-forcing hypotheseshypotheses1.1. Regionally document cycle break down Regionally document cycle break down
-North-south gradient-North-south gradient
2.2. Evaluate barriers to dispersal (via gene Evaluate barriers to dispersal (via gene flow) across a latitudinal gradientflow) across a latitudinal gradient
3.3. Radiocollar lynx to estimate model of Radiocollar lynx to estimate model of habitats habitats -Facilitate dispersal into South-Facilitate dispersal into South
4.4. Examine timeseries relative to climate data Examine timeseries relative to climate data to evaluate seasonal-forcingto evaluate seasonal-forcing
Obj 1. Cycles at Obj 1. Cycles at appropriate scaleappropriate scale
Untangling the SouthUntangling the South Reduced amplitudeReduced amplitude More variable periodicitiesMore variable periodicities Less synchronyLess synchrony
Compile harvest data Compile harvest data Alberta & BC Alberta & BC
Hudson’s Bay Company Hudson’s Bay Company Archives prior to1950 Archives prior to1950
Provincial traplines 1950 - Provincial traplines 1950 - 2006. 2006.
Aggregate appropriately Aggregate appropriately Analyze across a latitudinal Analyze across a latitudinal
gradient using time-series gradient using time-series methodsmethods
Poole & Mowat 2001
Lynx harvest by trapline1994-1999
Obj 2. Genetic view of Obj 2. Genetic view of dispersaldispersal
Dispersal – gene flowDispersal – gene flow Barriers in the increasingly Barriers in the increasingly
fragmented southfragmented south Large sample sizesLarge sample sizes
Previous workPrevious work Central & northern Alberta study Central & northern Alberta study
ignored south ignored south (Campbell & Strobeck)(Campbell & Strobeck)
Genetic drift in BC even w/ coarse-Genetic drift in BC even w/ coarse-scale testing scale testing (Schwartz et al. 2002, (Schwartz et al. 2002, Rueness et al. 2003)Rueness et al. 2003)
Differentiation in the US Differentiation in the US (Schwartz personal communication)(Schwartz personal communication)
Campbell & Strobeck 2006
Obj 2. Genetic view of Obj 2. Genetic view of dispersal cont.dispersal cont.
Planned methods Planned methods 2007-08 Alberta & BC trapping seasons 2007-08 Alberta & BC trapping seasons
Skin from peltsSkin from pelts Estimated n = 250Estimated n = 250
20 microsatellite loci effective in lynx 20 microsatellite loci effective in lynx Analysis Analysis
Genetic subpopulations using STRUCTURE software Genetic subpopulations using STRUCTURE software Isolation at individual levelIsolation at individual level
Isolation by distance Isolation by distance Isolation by landscape resistance (see Cushman et al. 2006)Isolation by landscape resistance (see Cushman et al. 2006)
Compare with habitat use data to unravel dispersal Compare with habitat use data to unravel dispersal dynamics dynamics
Obj 3. Habitat selection for Obj 3. Habitat selection for dispersaldispersal
Radiocollar sampleRadiocollar sample Estimated n = 20Estimated n = 20
Central Eastern Slopes AreaCentral Eastern Slopes Area Southwestern Alberta along RockiesSouthwestern Alberta along Rockies Exposed to forestry & land use changeExposed to forestry & land use change
Collaborate for robust modelCollaborate for robust model Washington sample near BC borderWashington sample near BC border NWT sample near Alberta borderNWT sample near Alberta border
AnalysisAnalysis Step selection function (SSF) Step selection function (SSF) Identify movement barriers throughout the region Identify movement barriers throughout the region Compare with evidence of gene-flow barriersCompare with evidence of gene-flow barriers
Obj 4. Climate analysisObj 4. Climate analysis Examine seasonality metricsExamine seasonality metrics
50+ years of data from weather stations50+ years of data from weather stations
Pacific Decadal Oscillation (PDO)Pacific Decadal Oscillation (PDO) Warmer winters, Warmer winters, precipitation, precipitation,
winter rain ratio, earlier snowpack melt winter rain ratio, earlier snowpack melt
Research key component(s) of seasonality Research key component(s) of seasonality Winter (November–March) PDO indexWinter (November–March) PDO index TemperatureTemperature snow pack depthsnow pack depth snow water equivalentsnow water equivalent season lengthseason length
Compare reduced seasonality & deterioration Compare reduced seasonality & deterioration of cycles of cycles
SignificanceSignificance
Explaining breakdown in cycle Explaining breakdown in cycle Dispersal in s. populationsDispersal in s. populations Seasonality hypothesized to maintain cycle Seasonality hypothesized to maintain cycle
Consequences - Consequences - fragmentationfragmentation & & climate changeclimate change Seasonality as primary driverSeasonality as primary driver
Show how climate change is altering population Show how climate change is altering population cycles cycles
Dispersal as primary driverDispersal as primary driver Habitat/dispersal maps identifying barriers in key Habitat/dispersal maps identifying barriers in key
habitats habitats Model modified human use for persistent Model modified human use for persistent
populations & habitat connectionspopulations & habitat connections