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Bear Populations in the NCDE & The Grizzly DNA Project . Jeff Stetz, M.Sc. Research Ecologist ~ Sinopah Wildlife Research Associates Ph.D. Candidate ~ Wildlife Biology ~ University of Montana Post-doctoral Researcher ~ University of Tennessee . Why am I here today?.
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Bear Populations in the NCDE & The Grizzly DNA Project Jeff Stetz, M.Sc. Research Ecologist ~ Sinopah Wildlife Research Associates Ph.D. Candidate~ Wildlife Biology ~ University of Montana Post-doctoral Researcher ~ University of Tennessee
Why am I here today? • Why do we care about (bear) populations? • What is reliable knowledge and why is it so important? • What tools did we use and why? • How did we estimate vital rates? • - individual and population level
Why am I here today? • Why do we care about conserving bear populations? • What is reliable knowledge and why is it so important? • What tools did we use and why? • How did we estimate vital rates? • - individual and population level
For starters, legal obligations • Federally listed Threatened species since 1975 • Need to maintain viable populations
Also, we like bears. • Culturally important for 10,000s of years
College mascots • Pro sports teams
Well, maybe not everyone does. • Vicious killer? • How dangerous, really?
1 person out of 16,000 commits murder but only 1 grizzly bear out of 50,000 ever kills someone and only 1 black bear out of one million does.
Also, conserving biodiversity: • Ecosystems • Species • Genes Unique role b/n Rescue Unique potential
Historic Grizzly Bear Range in N. America Need to increase our knowledge of population drivers for conservation Post-glacial Historic Present
Why am I here today? • Why do we care about bear populations? • What is reliable knowledge and why is it so important? • What tools did we use and why? • How did we estimate vital rates? • - individual and population level
knowledge ≠ wisdom We really suck at this…. wisdom Shooting for this… How do we get at any of this?
For most of us, ‘belief’ is based on: Estimates of precision and bias, which is tough to know, so we use The latest and greatest fancy-ass model
To get at truth…. λ The answer lies in understanding causation. π Ψ Why How, what Where, which When, who Closed-ended (yes/no) The $100,000 Question Pyramid
Instead, we spend our careers chasing λ π Ψ Why How, what Where, which And that’s what we did When, who Closed-ended (yes/no)
Why am I here today? • Why do we care about bear populations? • What is reliable knowledge and why is it so important? • What tools did we use and why? • How did we estimate vital rates? • - individual and population level
Research and monitoring…new ways • Use DNA “fingerprint” to identify and track bears • Non-rewarding lure • ‘non-invasive’ • Read: less bias If you have questions about the genetics: Pid, He, etc…
Research and monitoring…new ways • No bait • Natural behavior (read: less bias?) • Super easy
Snapshot of NCDE grizzly bear: • Population “size”
Estimated NCDE grizzly abundance - 2004 So we used the latest and greatest fancy-ass model Pr(det) < 1 Total ? ?
Huggins-Pledger closed population mark-recapture models - with temporal, group, and individual covariates - mixture-model for unmodeled heterogeneity in pr(det) AICcand model averaging
Estimated NCDE grizzly abundance - 2004 For the record, essentially the same as Lincoln-Petersen
Snapshot of NCDE grizzly bear: • Population “size” • Distribution
Abundance and “density” • Highest densities in GNP, Great Bear • “Healthy” densities in the Bob, Whitefish Range • Rough ideas of where, but no idea why
Geographic distribution • Continued expansion to east, west, and south • Occupied habitat 1.4x size of recovery zone (~3.1 million ha)
Snapshot of NCDE grizzly bear: • Population “size” • Distribution • Genetic health
Genetic “health” • Summary: • Bears assigned to sub-populations • Compared across time periods • Less difference now than <1998
Identifying potential barriers to geneflow Hwy 2 West Hwy 2 East Fst = 0.04 Fst = 0.01 Log (L(North)) Log (L(South)) Log (L(South)) Population fragmentation likely with unmitigated future development. Remember, crossing a road ≠ geneflow
Monitoring trend • “Snapshots” are great, but not the most important question • Montana FWP: population trend will guide management decisions • Did not identify method for estimating trend
‘‘The optimum monitoring system should … not require continuous capture and handling of animals… or highly trained and specialized personnel whose time is solely devoted to grizzly bear monitoring.’’
GPS data • Pros/cons: • Depends on objective/questions • Lots of information about relatively few animals • More risks to humans and animals • Can be difficult to reach targets in remote areas (read: sampling bias?)
Lots of work, but can be very powerful • FWP trend study • Density-distributed effort • Estimated from SSD that of female population: • 31% dep. offspring • 19% subadults • 50% adults • MANY other parameters • Estimated growth rate at 3% (95% CI: 0.93–1.10) • Not very precise; lengthy • Better options?
Using Noninvasive Methods to Monitor Grizzly Bear Population Status • Closed population model estimates of Pr(det) • Conducted simulations to evaluate open population models for trend • Suggest <5% CV within about 4 years
Using Noninvasive Methods to Monitor Grizzly Bear Population Status • USFS funded • Objectives • lambda • occupancy • relative density • genetic structure
Bear rub surveys • >5,000 rubs set up • 10s of thousands of hair samples per year • Analysis ongoing(?)
MONITORING TREND • Pradel (1996) models use CMR-type data to estimate: • realized rate of population change (rea) • apparent survival (φ) Photo: Dan Carney • and abundance (N) with > 2 surveys per year rea = Nt+1 / Nt= the net change given allpopulation processes: Nt+1= Nt + (births + immigration) – (deaths + emigration)
Getting back to the pyramid…. λ • Typically we address “applied” questions • The answer lies in understanding causation • Unfortunately… π Ψ Why How, what Where, which When, who Closed-ended (yes/no) The $100,000 Question Pyramid
Which N? Which λ? λ π Ψ
Know your population, dammit! Catch a larger percentage of adult bears, but all bears are represented in the sample* 92 2004 grizzly bear detections 71 16 76 11 6 2 8 M F Ad SA Yrl CoY
Role of Research • Locally, bears are doing well, with strong research efforts on-going • We’re learning what works and what doesn’t • Things can go bad quickly for bears if we let them
Locally, bears are doing well, with strong research efforts on-going • We’re learning what works and what doesn’t • We still can’t get at ‘why’ quite yet Post-glacial Historic Present
Bottom line? • Lots of tough questions • Some are actually important to conservation, but many are not • As professionals, we need to distinguish the two and identify the best way to answer them • Generally, this means doing good science • But we have to recognize it is an iterative process, and that other values can be far more important than data, ie beliefs vs truths