U.S. ENDANGERED SPECIES ACT

1. U.S. ENDANGERED SPECIES ACT ESA defines “species” as a species, subspecies or distinct population segment (amendment 1978). But gives no criteria for defining. In 1996, NMFS and USFWS agreed that Evolutionary Significant Units are are a reasonable interpretation of Distinct Population Segment.

2. What are Evolutionary Significant Units (ESUs)? Concept introduced by Ryder in 1986 Why? • Preserve the range of diversity within a species • Provide a guide for transplantation and reintroduction

3. ESU Definitions Waples (1991, 1995)An ESU is a population (or group of populations) that is (1) substantiallyreproductively isolatedfrom other conspecific population units, and (2) represents an important component in theevolutionary legacyof the species. Isolation does not have to be absolute but gene flow has to be restricted to the point that evolutionarily important differences occur. Evaluated by genetic data and tagging studies and biogeography

4. Waples (1991, 1995) Evolutionary legacyis defined as “genetic variability that is the product of past evolutionary events and that represents the reservoir upon which future evolutionary potential depends.” Evaluated using genetic data, ecology, life history traits/adaptive differences

5. ND5 SD18 ND3 ND6 SK10 SD14 ND1 SD17 MB3 ND10 ND2 SD20 AB4 MI12 MD6 ME6 NC3 DE2 MD3 MD7 MD1 NJ16 RI1 NC8 DE1 RI3 NY18 NC1 NC2 QB1 PL8 PI2 PI3 PI6 QB2 MD9 NY3 ME2 NY7 NY9 NY17 NC4 NY1 NY4 NY2 ME3 ME4 TURNST. Inland The Genetic Approach to ESUs Moritz 1994 ESUs should be reciprocally monophyletic for mtDNA alleles and show significant divergence of allele frequencies at nuclear loci. Atlantic

6. Hybridization Natural evolutionary process So why is it also a conservation challenge ? A B

7. Categories of Hybridization(Allendorf et al 2001)

8. Type 1-2 Virgin River Chub (1) Moorean Land Snail (2)

9. Type 3 Red and Yellow Shafted Flicker(3)

10. Type 4 Bull Trout

11. Type 5-6 West Slope Cutthroat (5) New Zealand Grey Duck (6)

12. Causes of Hybridization What human actions increase hybridization rates?

13. Positive Effects of Hybridization?

14. Negative Effects of Hybridization?

15. Endangered Species threatened by Hybridization ?

16. Hybrids and Legislation • ESA – case by case evaluation • IUCN – does not classify hybrids (except some plants that are treated as species)

17. What is Inbreeding?How does it differ from inbreeding depression?

18. Inbreeding Depression - Why? • Short-term Effects: • Increase homozygosity, reduced heterozygosity • Expression of deleterious recessive alleles • Loss of Evolutionary Potential • Decrease in # alleles = decrease in # resources available to respond to environmental stress

19. Ralls et al 1988 • First to quantify inbreeding effects • juvenille survival from 40 mammalian species • 1st degree relatives • 36/40 species comparisons had positive slopes • Cost of inbreeding? • Estimated survival of offspring of 1st degree relatives to unrelated animals

21. Studies Finding Increased Diversity is correlated with increased reproductive success Sonoran Topminnow Quattro and Vrijenhoek 1989 Science 245:976 Song Sparrow Keller et al 1998 Evol. 52:240 Male House Mouse Meagher et al 2000 PNAS 97:3324 Red Deer Slate et al 2000 PRSL 267:1657 Male Black Grouse Hoglund et al 2002 PRSL 269:711 Grey Seal, albatross Amos et al 2002 PRSL 268:2021 Pilot Whale

22. Decreased Diversity = Decreased resistance to Parasites Soay Sheep Coltman et al 1999 Evol. 53:1259 Bumblebees Baer & Hempel 1999 Nature 397:151 Song sparrow Reid et al 2003 PRSL 270:2151 Deer Mice Meagher 1999 Evol 53:1318. Fish Lively et al 1990 Nature 344:864 Sea lions Whitehouse et al 2003 Nature 422:35

23. Increased diversity = increased probability of individuals or pops surviving bottlenecks Song Sparrow Keller et al 1994 Nature 372:356 Butterfly Saccheri et al 1998 Nature 392:491

24. Climate Change and Inbreeding (Schiegg et al 2002 PRSL 269:1153-1159) - red-cockaded woodpeckers are laying eggs earlier in response to climate change - Inexperienced and inbred mothers do not lay earlier and show a decrease in fecundity

25. Genetic Rescue of Population Decline“Genetic Restoration” • Greater Prairie Chicken (Tympanuchus cupido pinnatus) • Weistemeier et al 1998 (Science 282:1695) • European adder (Vipera berus) • Madsen et al 1999 Nature 402:34 • Florida Panther (Felis concolor corci) • Ellis et al 1999 (USFWS report) • European grey wolf (Canis lupus) • Vila et al 2003 (PRSL 270:91) • Bighorn Sheep (Ovis canadensis) • Hogg et al 2006 (PRSL 273:1491) • Dinizia excelsa (Fabaceae) canopy emergent tree in Amazona • Dick 2001Proc. R. Soc. Lond B 268:2391

26. Outbreeding Depression • Can occur when individuals from different geographic regions with different gene combinations breed • Results in a decrease in fitness (fertility, survival) of offspring • Why? • local adaptation - gene pool may be adapted to local environment • co-adaptation - gene pool is internally balanced with respect to reproductive fitness, ie different numbers or types of chromosomes

27. Outbreeding Depression (examples) • Ibex in Czech. went extinct • Re-introduced from Austria • Augmentation from Turkey • Hybrids rutted at different times, kids were born in Feb. • Result: entire population went extinct • Many examples in plant communities also

28. Conservation Management Implications regarding gene flow • a beneficial evolutionary force - increases effective population size, maintains genetic variation • A constraining evolutionary force - outbreeding depression, preventing local adaptation, decreases probability of speciation. • What should be the goal?