COURSE SCHEDULE. Other applications of genetics in conservation Resolving taxonomic uncertainty

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1 Tutorials: Next week, Tues. 5 Oct. meet in from of Library Processing entre (path near Woodward) at 2pm. We re going on a walk in the woods, so dress appropriately! Following week, Tues. 2 Oct.: Global economics & conservation (no prep.) + QUIZ genetics and metapopulations. The week after that, Tues. 9 Oct.: Invasions and species diversity (required readings) + QUIZ landscape ecology, habitat fragmentation / destruction (incl. Thomas et al. paper from earlier). OURSE SHEDULE I. Foundations of discipline. II. Scientific underpinnings. III. Threats to biodiversity. IV. Solutions. V. Perspectives & case studies. Last time: onservation genetics Today: Metapopulations Other applications of genetics in conservation Forensics International Whaling ommission bans commercial whaling in 986 Some harvests for scientific purposes can still be sold ut is illegal whale meat still making it to market? Phylogenetic tree using mtdna from whale meat sold in Asian markets Protected species Not whales aker & Palumbi (994) Science Other applications of genetics in conservation Resolving taxonomic uncertainty Some distinctions are clear. others are not so clear Phylogenetic Relationships (DNA sequence data) Listed as entity Possible hybridization April 2006, NWT 2 listed populations

2 Distinction of subpopulation units for grizzly bears in anada is difficult grizzly bears essentially occupy continuous habitat Other applications of genetics in conservation Resolving taxonomic uncertainty Two different species of orangutan diverged >.5 million years ago extant extinct Sumatran orangutan Recognition of distinct populations arbitrary Xu & Arnason (996) Journal of Molecular Evolution ornean orangutan eyond genetics to adaptive evolution Heavy-metal tolerance in plants on mine tailings Industrial pollution and peppered moths Native predators evolve resistance to toxins in exotic prey Anthoxanthum odoratum 2

3 Key points on population biology (incl. genetics) Population models used to assess viability (extinction risk), to compare health of different populations, and to identify key life stages for intervention Small populations are sensitive to many factors that increase extinction risk, incl. demographic stochasticity, loss of genetic variation, inbreeding depression Environmental stochasticity is extremely important: long-term population trend depends on the product of individual λ s; more variable λ (for a given mean) leads to lower long-term pop. growth Matrix population models help identify life stages especially important for population viability Genetic diversity (lost easily from small pops.) confers evolutionary potential, fitness benefit, and possible benefits for the diversity of dependent species onservation genetics aids conservation by: characterizing genetic/evolutionary aspects of population viability (e.g., inbreeding depression), delineating the units of conservation, guiding the design of breeding programs. From populations to metapopulations THE METAPOPULATION - Small populations within fragments prone to extinction - Recolonization of empty from occupied - Persistence at regional scale: extinction-colonization balance EXTINTION AND OLONIZATION x x 2 habitat, 5 are occupied 2 local extinctions, 3 colonized now 6 are occupied 3

4 EXTINTION AND OLONIZATION A simple model: the Levins model P = the proportion of that are occupied c = colonization rate (probability an empty patch is colonized) e = extinction rate (probability an occupied patch goes extinct) Assume a large set of identical with global dispersal dp/dt = cp( P) ep What proportion of do we expect to be occupied? Solve equation for dp/dt = 0 2 habitat, 4 are occupied 2 local extinctions, 3 colonized now 6 are occupied ^ P = e/c In the Levins metapopulation model, what should this relationship look like? dp/dt = cp( P) ep In the Levins metapopulation model, what should this relationship look like? A # empty colonized / time # empty colonized / time D Proportion of occupied Proportion of occupied 4

5 In the Levins metapopulation model, what should this relationship look like? Patch occupancy is determined by a balance between colonization and extinction olonization & extinction are independent A # populations extinct / time # empty colonized / time # populations extinct / time D Proportion of occupied Equilibrium Proportion of occupied baseline baseline Smaller = higher extinction (colonization or extinction) 2 3 Patch occupancy Landscape habitat distribution A same patch size, same total habitat,, Match each landscape with its corresponding colonization/extinction curves: (A) A, 2, 3 (), 2A, 3 (), 2A, 3 (D), 2, 3A (E), 2, 3A (colonization or extinction) 2 3 Patch occupancy Landscape habitat distribution same total habitat, A same patch size,, Sparser = lower colonization Match each landscape with its corresponding colonization/extinction curves: (A) A, 2, 3 (), 2A, 3 (), 2A, 3 (D), 2, 3A (E), 2, 3A 5

6 ^ P = e/c A simple (but important) lesson from a simple model riterion for metapopulation persistence: e/c <, or e < c What if we destroy some habitat? Fewer sources of colonization Same local extinction probability Push metapopulation closer to extinction threshold uilding in complexity / reality into metapopulation models: Patch-specific area and isolation Patch shape Patch quality Patch destruction / creation This is true even if we destroy unoccupied habitat Probability of occurence uilding in complexity (i.e., reality) Not all are equal: size & connectivity Melica uniflora elgium landscape Probability of occurence Anemone nemorosa elgium landscape A classic metapopulation: the Glanville Fritillary Small populations specialized on particular host plant species High local extinction and colonization dependent on area & connectivity Regional persistence Log patch area (m) Patch connectivity Ilkka Hanski & colleagues Åland, Finland 6

7 uilding in complexity (i.e., reality) Not all are equal: habitat suitability Source-sink metapopulations Some populations maintained only by dispersal from elsewhere Forest fragmentation in the midwestern U.S. uilding in complexity (i.e., reality) Not all are static in time Each year, some destroyed, some created Patch turnover increases extinction rate We constructed a model to incorporate this owbird parasitism so high that small fragments are demographic sinks for song birds Year And the model was consistent with data on patch occupancy patterns for plant species in Lincolnshire, UK Robinson et al. (995) Science Verheyen et al. (2004) Ecology So we can ask the model, What are the consequences of different rates of patch turnover? Metapopulation viability analysis: Key conservation messages from metapopulation theory Poor colonizer, extinction resistant Mercurialis perennis Good colonizer, extinction prone Taraxacum officinale (dandelion) - Unoccupied but suitable habitat can be very important - Occupied habitat may not be suitable - Small changes to the landscape my mean big changes for wild species - What happens locally depends on regional context Verheyen et al. (2004) Ecology 7