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The influence of dispersal & seasonality on lynx dynamics in W. Canada Click here for audio Gabriela Yates & Mark Boyce University of Alberta

Hudson’s Bay Co. Fur Trading Records & Mac. Lulich 1937

Cycle breakdown- localized areas n Lynx harvest in northern Alberta (Wood Buffalo Nat. Park) compared to Nordegg, Alberta site (Central Eastern Slopes). Boyce et al. 2005. Biological Conservation 126: 395. Mullen. 2006. M. S. Thesis, University of Alberta.

Cycle breakdown- provincial scale Results of spectral analysis of lynx population timeseries from harvest data AB & BC have significant cycles at a provincial scale Murray et al. In press. Journal of Wildlife Management.

Cycle breakdown- provincial scale Results of spectral analysis of lynx population timeseries from harvest data Border States do NOT have significant cycles Murray et al. In press. Journal of Wildlife Management.

Biological mechanisms affecting southern cycles n Predator dispersal Pulse from epicenter (Ranta et al. 1997) n Southern prey densities too low to support cyclic dynamics n (Steury & Murray 2004) Population sink n Immigration pulse from the core (Mc. Kelvey et al. 2000) n n Hypotheses 1: Southern dynamics & persistence dependent on dispersal

Biological mechanisms affecting southern cycles n Climate - seasonality n Synchrony vs. asynchrony (Stenseth et al. 1999, 2004) n NAO n East-west (provincial statistics) n Sunspot driven weather (Sinclair et al. 1993, Sinclair & Gosline 1997) n Doesn’t explain eastern asynchrony (affected by NAO) n n Seasonality produces phase locking (King & Schaffer 2001) Hypothesis 2: Weakened seasonality reduces seasonal forcing sustaining multi-year oscillator

Research question n Are changes in lynx dynamics related to. human induced change? n Barriers to predator dispersal n Fragmentation due to industrial/urban development n Weakened seasonality n Temperatures of the boreal increasing since 70 s n Climate change may have widespread consequences

Research objectives n Evaluate dispersal vs. seasonal-forcing hypotheses 1. Regionally document cycle break down -North-south gradient 2. Evaluate barriers to dispersal (via gene flow) across a latitudinal gradient 3. Radiocollar lynx to estimate model of habitats -Facilitate dispersal into South 4. Examine timeseries relative to climate data to evaluate seasonal-forcing

Obj 1. Cycles at appropriate scale n Untangling the South n n Reduced amplitude More variable periodicities Less synchrony Compile harvest data n Alberta & BC n n n Lynx harvest by trapline 1994 -1999 Poole & Mowat 2001 n Hudson’s Bay Company Archives prior to 1950 Provincial traplines 1950 - 2006. Aggregate appropriately Analyze across a latitudinal gradient using time-series methods

Obj 2. Genetic view of dispersal n Dispersal – gene flow n n n Barriers in the increasingly fragmented south Large sample sizes Previous work n Central & northern Alberta study ignored south (Campbell & Strobeck) n Genetic drift in BC even w/ coarse-scale testing (Schwartz et al. 2002, Rueness et al. 2003) n Differentiation in the US (Schwartz personal communication) Campbell & Strobeck 2006

Obj 2. Genetic view of dispersal cont. n Planned methods n 2007 -08 Alberta & BC trapping seasons n n Skin from pelts Estimated n = 250 20 microsatellite loci effective in lynx Analysis n n Genetic subpopulations using STRUCTURE software Isolation at individual level n n n Isolation by distance Isolation by landscape resistance (see Cushman et al. 2006) Compare with habitat use data to unravel dispersal dynamics

Obj 3. Habitat selection for dispersal n Radiocollar sample n n Central Eastern Slopes Area n n n Southwestern Alberta along Rockies Exposed to forestry & land use change Collaborate for robust model n n n Estimated n = 20 Washington sample near BC border NWT sample near Alberta border Analysis n n n Step selection function (SSF) Identify movement barriers throughout the region Compare with evidence of gene-flow barriers

Obj 4. Climate analysis n Examine seasonality metrics n n Pacific Decadal Oscillation (PDO) n n Warmer winters, precipitation, winter rain ratio, earlier snowpack melt Research key component(s) of seasonality n n n 50+ years of data from weather stations Winter (November–March) PDO index Temperature snow pack depth snow water equivalent season length Compare reduced seasonality & deterioration of cycles

Significance n Explaining breakdown in cycle Dispersal in s. populations n Seasonality hypothesized to maintain cycle n n Consequences - fragmentation & climate change n Seasonality as primary driver n Show climate change is altering population cycles n Dispersal as primary driver n Habitat/dispersal maps identifying barriers in key habitats n Model modified human use for persistent populations & habitat connections

Questions? Advice? Gabriela Yates Mark Boyce University of Alberta Project Website: www. ualberta. ca/~gyates/projectlynx