Why char are like onions: Peeling away the layers of char biodiversity & their implications for conservation with special reference to bull trout north of the 49th parallel Eric Taylor University of British Columbia
Outline Understanding the origins of biodiversity Char : the outside of the onion AC and DV: same coin, two sides? The (re)emergence of Bull trout Bull trout more than meets the eye Conservation status of Bull trout: north of the 49 th! Conclusions
Evolution and Conservation (1999) Complementarity of systematic, ecological, and evolutionary agendas
Understanding the Nature and Origins of Biodiversity Oncorhynchus Salmo Salvelinus Hucho
Char: a Mixed Blessing for Biologists! No higher praise can be given to a Salmonid than to say, it is a charr Jordan and Evermann (1896) E. Keeley But, a challenge taxonomically! The taxonomy of char: extremely involved an timeconsuming (Vladykov 1954)
Even the Angler Finds them Confusing at Times! In Fisherman: 1994
Char: Three Well-Recognized Taxa in North America pre-1978 Arctic char complex Lake trout Brook trout
Arctic char : Why Fishes are Like Onions Salvelinus alpinus (Linneaus, 1758) Widespread and morphologically plastic single species
Morphological Differences Between Dolly Varden and Arctic Char: known at least since the 60s ADF&G
Arctic char Turned Out to Be TWO Species Arctic char Dolly Varden
Arctic char Turned Out to Be TWO Species: Perhaps Not! Arctic char Dolly Varden Therefore, the species status of S. malma is questionable and it cannot be confirmed as a sister taxon to all other S. alpinus (Behnke 1984). Brunner et al. (2000) -indistinguishable mtdnas
Contact Zones in Char: Dolly Varden and Arctic char are not two sides of the same coin E. Taylor, E. Lowery, T. Quinn, A. Elz, A. Lilliesträle
Sympatry in western Alaska! Sympatry in Alaska!
Iliamna: Clear Morphological Differences 3 2 1 PC 2 0-1 -2-3 -4-4 -3.2-2.4-1.6-0.8 0 0.8 1.6 2.4 PC 1 18 16 14 Frequency 12 10 8 6 4 2 0 12 18 24 30 36 42 48 54 60 66 Pyloric caeca no.
Two Genetic Populations DV AC Simulated hybrids Aleknagik and Iliamna
Genetic Assignment Tests with Known Baselines AC DV Aleknagik and Iliamna
What Contributes to Isolation? 1. Differences in habitat limit opportunities for intermating (premating isolation) 2. Adaptation to alternative habitats and life-histories (lake-resident, stream-resident, anadromous) could contribute to ecological selection against hybrids.
Distribution of Arctic char and Dolly Varden - 1961
A Closer Look at Dolly Varden
Morphologically Diversity Had Geographic Structure (in Sympatry!) A, C = Bull trout BT DV BT B = Dolly Varden BT DV Salmo spectabilis Salmo confluentus BT DV Salvelinus spectabilis Salvelinus malma Salvelinus confluentus Cavender (1978)
Two Kinds of DV Split Across the Coast Mountains Thutade Lake
Two Species of Char that Sometimes Interbreed: Genetic Analysis in Sympatry Numbers of fish 350 300 250 200 150 100 50 0 Hybrids DV H1 H2 H3 H4 BT Fish type
How is Divergence Maintained with Interbreeding: Natural Selection Acting When Stream-Dwelling Juveniles? DOLLY VARDEN BULL TROUT
Habitat Use is Very Similar Proportion of observations 0.6 0.5 0.4 0.3 0.2 0.1 0 All P > 0.1 MC Pool MC Riffle SC Pool SC Riffle Bull trout Dolly Varden
Diet Overlap is Extensive Hymenopt. 8% Diptera adults 34% Diptera larvae 8% Colopt. 6% Dolly Varden Ephemeropt. 33% Tricopt. 3% Plecopt. 8% 14.3% 5.5% 10.6% 11.3% 11.4% 0.6% Bull trout 46% Schoener s diet overlap = 0.71-0.89
But, The Two BT and DV Use Different Habitats in Thutade Lake Across their Whole Life History Dolly Varden Bull Trout
Alternative Migratory Life-Histories in Sympatry
Life History Niche Partitioning Frequency 50 40 30 20 10 0 Parental niches Disruptive selection Hybrids Life history axis (migratory vs. resident)
Parallels between AC and DV in Alaska and BT and DV in BC in Life History Partitioning: A Great Study Needing a Studier! AK BC Bull trout Dolly Varden
So, Why are Char Like Onions?? Arctic char Arctic char + Bull trout + Dolly Varden Research in has peeled away the skin to reveal THREE species, not one!
But, More To the Story Intraspecific Diversity and Conservation Units in Bull Trout in Canada Squamish R., BC, coastal bull trout Burnt R., BC, interior bull trout
Canada s Species at Risk Act, DUs, and COSEWIC Species at Risk Act (SARA) 2004 Species assessment reports commissioned, reviewed, status recommendations by COSEWIC Committee on the Status of Endangered Wildlife in Canada arm s length from gov t Assesses Wildlife Species Designatable Units
Designatable Units Subspecies, variety, or geographically or genetically distinct population(s) recognized when a single status designation for a wildlife species is not sufficient to accurately portray probabilities of extinction within the wildlife species. (aka legal species within taxonomic species ) If not a subspecies, DUs can be population(s) that satisfy two criteria: (1) Discrete and (2) Evolutionary Significance
Designatable Units (1) Discrete: at least one of - genetically distinct (behaviour to DNA sequences); Biogeographically distinct; Large range disjunction (2) Evolutionary significant - Deep phylogeographic divisions (pre-glacial); persistence in unique or unusual ecological setting; local adaptations; only surviving population; loss would induce large gap in range,
Status Review and Assessment of Bull Trout in Canada: What to Assess??
Two Major Genetic Lineages of Bull Trout in NA mtdna Supported by Morphological, Life-history (anadromy) differences Microsatellites (Hass and McPhail 2001; Brenkman and Corbett 2005) (Taylor et al. 1999; Taylor and Costello 2006)
Genetic Lineages Strongly Associated with Geography: Distinct Glacial Histories Chehalis (1) Columbia (2)
Two Genetic Lineages Split Across Four Freshwater Biogeographic Zones Equals 4 2 3 1 5
Five DUs of Bull Trout in Canada Coastal Genetic Lineage - DU1 Interior Genetic Lineage -Pacific populations - DU2 -Western Arctic Populations - DU3 -Yukon Populations - DU4 -Saskatchewan-Nelson Populations - DU5
Risk Status of Core Areas ( metapopulations ) by DU 60 50? Number of core areas 40 30 20 10? DU1 (Coast) DU2 (WArc) DU3 (Yuk) DU4 (Sask-Nel) DU5 (Pac) 0 High Risk At Risk Potential Risk Low Risk Not Ranked Extirpated Increasing risk status (modified ranks from Fredenberg et al. 2005)
Risk Status by Jurisdiction Populations are the eastern margins of range are at greatest risk (Alberta): limited range and lots of development (oil and gas; impoundments; forestry and roads) Knowledge of distribution of DU1 (coastal bull trout) incomplete in BC - likely rare All but ONE of unranked populations are in BC, NWT, or Yukon we have lots of work to do
Conclusions Alpha taxonomy of char more-or-less worked out (at least in NA!) Ecological and genetic factors promoting co-existence? Basic demographic information lacking in huge areas (BC, NWT) Critical lack of information for Dolly Varden
Research Sponsors Gwich in Renewable Resources Board Parks Canada BC Government
Paraphyly of S. alpinus mtdna Brunner et al. (2001), Taylor et al. (2008)