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The Use of EDGE (Evolutionary Distinct Globally Endangered) and EDGE-Like Metrics to Evaluate Taxa for Conservation

  • Nick J. B. Isaac
  • William D. Pearse
Chapter

Abstract

The idea of setting conservation priorities using phylogenetic information has been in the literature for decades. Since 2007 it has been implemented by the EDGE of Existence program at the Zoological Society of London. There are now “EDGE lists” of mammals, birds, amphibians, sharks, and corals: all these lists prioritize species that are both highly threatened and evolutionarily distinct (i.e., they have few close relatives). In this chapter, we review the metrics used to calculate priority scores for species on EDGE lists. As the EDGE of Existence program enters its second decade, this is an appropriate moment to reflect on how the process of selecting species could be improved or streamlined. A suite of metrics have been proposed as alternatives or improvements to the original EDGE metric, each differing in a number of important ways, such as how they handle uncertainty in their underlying data. Perhaps the most profound differences among these metrics reflect differences in how threat status and phylogenetic information are scaled to calculate the prioritization metric and in whether (and how) they incorporate the principle of complementarity. We discuss these choices of metric in the context of the properties of each metric and what they have to say about balance between how much we value the existence of each species (its phylogenetic position) and the risk that it would be lost due to extinction.

Notes

Acknowledgments

This chapter is dedicated to the memory of our friend and colleague, Ben Collen. We thank one anonymous reviewer for constructive comments on an earlier draft. Arne Mooers has been a complete star and great supporter of the EDGE program since its inception and provided valuable advice and discussion on the material content of this chapter. We are grateful to the participants in the “EDGE 2.0” workshop (organised by Rikki Gumbs, Nisha Owen, Will Pearse, and James Rosindell) for lively discussions on some of the topics presented here, and the outputs of that meeting will address many of the key issues outlined here.

References

  1. Agapow P-M, Bininda-Emonds OR, Crandall, KA, Gittleman JL, Mace GM, Marshall JC, Purvis A (2004) The impact of species concept on biodiversity studies. Q Rev Biol 79:161–179Google Scholar
  2. Bland LM, Collen B, Orme CDL, Bielby J (2015) Predicting the conservation status of data-deficient species. Conserv Biol 29:250–259.  https://doi.org/10.1111/cobi.12372CrossRefPubMedGoogle Scholar
  3. Collen B, Turvey ST, Waterman C et al (2011) Investing in evolutionary history: implementing a phylogenetic approach for mammal conservation. Philos Trans R Soc Lond Ser B Biol Sci 366:2611–2622.  https://doi.org/10.1098/rstb.2011.0109CrossRefGoogle Scholar
  4. Faith DP (1992) Conservation evaluation and phylogenetic diversity. Biol Conserv 61:1–10.  https://doi.org/10.1016/0006-3207(92)91201-3CrossRefGoogle Scholar
  5. Faith DP, Walker PA (1996) Integrating conservation and development: incorporating vulnerability into biodiversity-assessment of areas. Biodivers Conserv 5:417–429Google Scholar
  6. Faith DP (2008) Threatened species and the potential loss of phylogenetic diversity: conservation scenarios based on estimated extinction probabilities and phylogenetic risk analysis. Conserv Biol 22:1461–1470.  https://doi.org/10.1111/j.1523-1739.2008.01068.xCrossRefPubMedGoogle Scholar
  7. Faith DP (2015a) Phylogenetic diversity, functional trait diversity and extinction: avoiding tipping points and worst-case losses. Philos Trans R Soc B Biol Sci 370:20140011–20140011.  https://doi.org/10.1098/rstb.2014.0011CrossRefGoogle Scholar
  8. Faith DP (2015b) The unimodal relationship between species’ functional traits and habitat gradients provides a family of indices supporting the conservation of functional trait diversity. Plant Ecol 216:725–740.  https://doi.org/10.1007/s11258-015-0454-zCrossRefGoogle Scholar
  9. Forest F, Crandall KA, Chase MW et al (2015) Phylogeny, extinction and conservation: embracing uncertainties in a time of urgency. Philos Trans R Soc Lond Ser B Biol Sci 370:20140002.  https://doi.org/10.1098/rstb.2014.0002CrossRefGoogle Scholar
  10. Hartmann K (2013) The equivalence of two phylogenetic biodiversity measures: the Shapley value and fair proportion index. J Math Biol 67:1163–1170.  https://doi.org/10.1007/s00285-012-0585-yCrossRefPubMedGoogle Scholar
  11. Hey J, Waples RS, Arnold ML et al (2003) Understanding and confronting species uncertainty in biology and conservation. Trends Ecol Evol 18:597–603.  https://doi.org/10.1016/j.tree.2003.08.014CrossRefGoogle Scholar
  12. Huson DH, Bryant D (2006) Application of phylogenetic networks in evolutionary studies. Mol Biol Evol 23:254–267.  https://doi.org/10.1093/molbev/msj030CrossRefPubMedGoogle Scholar
  13. Isaac NJB, Purvis A (2004) The “species problem” and testing macroevolutionary hypotheses. Divers Distrib 10:275–281.  https://doi.org/10.1111/j.1366-9516.2004.00092.xCrossRefGoogle Scholar
  14. Isaac NJB, Mallet J, Mace GM (2004) Taxonomic inflation: its influence on macroecology and conservation. Trends Ecol Evol 19:464–469CrossRefPubMedGoogle Scholar
  15. Isaac NJB, Turvey ST, Collen B et al (2007) Mammals on the EDGE: conservation priorities based on threat and phylogeny. PLoS One 2:e296.  https://doi.org/10.1371/journal.pone.0000296CrossRefPubMedPubMedCentralGoogle Scholar
  16. Isaac NJB, Redding DW, Meredith HM, Safi K (2012) Phylogenetically-informed priorities for amphibian conservation. PLoS One 7:1–8.  https://doi.org/10.1371/journal.pone.0043912CrossRefGoogle Scholar
  17. Jensen EL, Mooers AØ, Caccone A, Russello MA (2016) I-HEDGE: determining the optimum complementary sets of taxa for conservation using evolutionary isolation. PeerJ 4:e2350.  https://doi.org/10.7717/peerj.2350CrossRefPubMedPubMedCentralGoogle Scholar
  18. Jetz W, Thomas GH, Joy JB et al (2014) Global distribution and conservation of evolutionary distinctness in birds. Curr Biol 24:919–930.  https://doi.org/10.1016/j.cub.2014.03.011CrossRefPubMedGoogle Scholar
  19. Kuhn TS, Mooers AØ, Thomas GH (2011) A simple polytomy resolver for dated phylogenies. Methods Ecol Evol no-no.  https://doi.org/10.1111/j.2041-210X.2011.00103.x
  20. Mooers AØ, Faith DP, Maddison WP (2008) Converting endangered species categories to probabilities of extinction for phylogenetic conservation prioritization. PLoS One 3:1–5.  https://doi.org/10.1371/journal.pone.0003700CrossRefGoogle Scholar
  21. Mooers A, Gascuel O, Stadler T et al (2012) Branch lengths on birth-death trees and the expected loss of phylogenetic diversity. Syst Biol 61:195–203.  https://doi.org/10.1093/sysbio/syr090CrossRefPubMedGoogle Scholar
  22. Nunes LA, Turvey ST, Rosindell J (2015) The price of conserving avian phylogenetic diversity: a global prioritization approach. Philos Trans R Soc L B Biol Sci 370:20140004.  https://doi.org/10.1098/rstb.2014.0004CrossRefGoogle Scholar
  23. Pearse WD, Chase MW, Crawley MJ et al (2015) Beyond the EDGE with EDAM: prioritising british plant species according to evolutionary distinctiveness, and accuracy and magnitude of decline. PLoS One 10.  https://doi.org/10.1371/journal.pone.0126524
  24. Purvis A, Hector A (2000) Getting the measure of biodiversity. Nature 405:212–219.  https://doi.org/10.1038/35012221CrossRefPubMedGoogle Scholar
  25. Redding DW, Mooers AØ (2006) Incorporating evolutionary measures into conservation prioritization. Conserv Biol 20:1670–1678.  https://doi.org/10.1111/j.1523-1739.2006.00555.xCrossRefPubMedGoogle Scholar
  26. Redding DW, Mazel F, Mooers AØ et al (2014) Measuring evolutionary isolation for conservation. PLoS One 9:e113490.  https://doi.org/10.1371/journal.pone.0113490CrossRefPubMedPubMedCentralGoogle Scholar
  27. Steel M, Mimoto A, Mooers AØ (2007) Hedging our bets: the expected contribution of species to future phylogenetic diversity. Evol Bioinformatics Online 3:237–244Google Scholar
  28. Stein RW, Mull CG, Kuhn TS et al (2018) Global priorities for conserving the evolutionary history of sharks, rays and chimaeras. Nat Ecol Evol 2:288–298.  https://doi.org/10.1038/s41559-017-0448-4CrossRefPubMedGoogle Scholar
  29. Vane-Wright RI, Humphries CJ, Williams PH (1991) What to protect?—systematics and the agony of choice. Biol Conserv 55:235–254.  https://doi.org/10.1016/0006-3207(91)90030-DCrossRefGoogle Scholar
  30. Weitzman ML (1992) On diversity. Q J Econ 107:363–405.  https://doi.org/10.2307/2118476CrossRefGoogle Scholar
  31. Weitzman ML (1998) The Noah’s ark problem. Econometrica 66:1279–1298CrossRefGoogle Scholar
  32. Wilson KA, McBride MF, Bode M, Possingham HP (2006) Prioritizing global conservation efforts. Nature 440:337–340.  https://doi.org/10.1038/nature04366CrossRefPubMedGoogle Scholar
  33. Witting L, Loeschcke V (1995) The optimization of biodiversity conservation. Biol Conserv 71:205–207.  https://doi.org/10.1016/0006-3207(94)00041-NCrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Centre for Ecology and HydrologyWallingfordUK
  2. 2.Department of Biology and Ecology CenterUtah State UniversityLoganUSA

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