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Biodiversity I: meaning and measurement

Biodiversity I: meaning and measurement. Bio 415/615. Questions. What are the major components of ‘biodiversity’ as broadly defined? What is species evenness, and how is it different from species richness? How is the concept of biodiversity related to the science of phylogenetics?

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Biodiversity I: meaning and measurement

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  1. Biodiversity I: meaning and measurement Bio 415/615

  2. Questions • What are the major components of ‘biodiversity’ as broadly defined? • What is species evenness, and how is it different from species richness? • How is the concept of biodiversity related to the science of phylogenetics? • How do alpha and beta diversity differ? • What role do keystone species play in ecosystems?

  3. Historical Conservation Themes • Individual species or groups (Intrinsic rights and utilitarianism) • Wild, pristine, human-free places (Preservation Ethic) • Wise use, sustained yield, sustainability (Resource Conservation Ethic) • Holism of Leopold, people in the equation (Evolutionary-Ecological Land Ethic) • And now: Biodiversity

  4. Defining Biodiversity • Definitions…measurement…monitoring

  5. The variety of life in all its forms, levels and combinations. Includes ecosystem diversity, species diversity, and genetic diversity. IUCN, UNEP and WWF, 1991

  6. Biodiversity is the variability among all living organisms from all sources, including, inter alia, terrestrial, marine and other aquatic ecosystems and ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems. Convention on Biological Diversity

  7. The totality of the inherited variation of all forms of life across all levels of variation, from ecosystem to species to gene. Edward O. Wilson

  8. Biodiversity means the whole variety of life on Earth. Biodiversity is the grand diversity of life on Earth and all the interconnections that support these myriad forms of life. Biodiversity…is perhaps most commonly defined as "the full variety of life on Earth."

  9. "A definition of biodiversity that is altogether simple, comprehensive, and fully operational ... is unlikely to be found.“(Noss 1990)

  10. Extremes • Narrow definition: species richness • Inclusive definition (Noss): • Genes, species, ecosystems • Composition, structure, function/process

  11. Inclusive hierarchy • Species diversity (numbers and abundances of species) • Genetic diversity (numbers and abundances of genes, genotypes, genetic material) • Ecosystem diversity (biotic and abiotic components)

  12. Noss 1990 SCALE as integral to biodiversity concepts

  13. Species, MUs, and ESUs • Species concepts • Morphological • Biological • Phylogenetic • MUs=Management units • ESUs=Evolutionarily significant units

  14. What’s a species? Biological Species Concept: "species are groups of interbreeding natural populations that are reproductively isolated from other such groups“ (Ernst Mayr) Horse + Donkey = Mule Morphological Species Concept: a group of individuals that look like each other, not necessarily due to common ancestry Oak Trees, Ducks

  15. What’s a species? Humans, other apes split 6-8 mya Everyone alive today shares a common ancestor from ca. 130,000 ybp Phylogenetics: use of genetic information to identify shared ancestry Phylogenetic species: group of individuals that shares a common ancestor Also called cladistics

  16. Cladistics / Phylogenetics

  17. Integrated molecular toolsto quantify biodiversity Taxonomy-free! • Phylogeny • Identity: DNA barcodes • Individual variation

  18. Janzen’s biodiversity gadget: a decade away? Captain, I’m picking up the hybrid genotype of Polystichum acrostichoides and lonchitis…

  19. Types of species for conservation • Indicators • Keystones • Umbrellas • Flagships • Vulnerables • Foundation

  20. Indicator species • A species representative of an entire ecosystem, habitat, ecological process, or environmental condition American dipper needs clear, unsilted streams to forage effectively for food

  21. Indicator species Carnegia gigantea Hastings and Turner, The Changing Mile

  22. Keystone Species – A species that has a significant effect on the presence and abundance of many other species in a community: far out of proportion to its biomass Starfish – Pisaster Sea Otters

  23. Trophic Cascade

  24. Urchin barren: no kelp!

  25. Ecosystem Engineers / Transformers – Organisms who build a structure (or otherwise modify a habitat) that allows an entire community to exist Beaver dams & ponds Animals nest

  26. Foundational Species – Organisms whose presence provides the structure that allows an entire community to exist Trees in a forest Kelp in a kelp forest Pickleweed in an estuary

  27. ‘Foundational’ ‘Ecosystem Engineers – Transformers’

  28. Other species concepts • Umbrella species have ranges that encompass many other (imperiled) species: protect it’s habitat, and you protect the rest • Flagship species are conservation icons: charismatic, lots have human-like faces (esp. eyes) and sometimes cuddly

  29. Species diversity defined • Species richness = number of species • Species evenness or equitability = more similar in relative abundance

  30. Which has the highest diversity? Community 1 Community 2 5 monkeys 5 herons 5 lions 5 cows 5 frogs 1 monkey 18 herons 2 lions 2 cows 1 frog 1 reptile

  31. Which community has the highest evenness, which has the lowest? Community 1: 10 toads, 10 rabbits, 10 lions, 10 fish Community 2: 4 toads, 4 rabbits, 4 sheep, 4 elephants Community 3: 7 toads, 3 rabbits, 3 sheep, 3 elephants Community 4: 7 toads, 3 rabbits, 3 sheep, 1 elephant

  32. Diversity indices Emergent properties of communities, integrating richness and evenness. Example: Shannon diversity (H’): pi = proportional abundance of species I Consider transformation: e^H’ (easier to interpret)

  33. Diversity indices “A community’s diversity index is merely a single descriptive statistic, only one of the many needed to summarize its characteristics, and by itself, not very informative” (Pielou 1975)

  34. Rank-abundance Graph Community with 10 frogs, 7 rats, 4 chipmunks, 2 mice 10 8 6 4 2 0 Abundance 1 2 3 4 Rank by abundance

  35. A more realistic distribution of abundance generally requires a log scale 889 oak trees, 100 bay trees, 10 maple trees, 1 birch tree 100 10 1 .1 .01 % of individuals 1 2 3 4 Rank by abundance

  36. Length of the line changes with diversity Slope generally changes with diversity Slope changes because of the change in evenness that generally correlates with system diversity What would the slope be in a perfectly even community?

  37. Alpha vs. beta diversity Alpha diversity: single location. Eg, per area. (within site) Beta diversity: differentiation diversity; change (between sites) Alpha is simple. Beta is not!

  38. Often tied to gradient analysis: ie, measuring diversity within and among plots. But there are many ‘non-gradient’ forms.

  39. Beta diversity (species turnover) Community 1: Community 2: A, B, C, D E, F, G, H Community 3: Community 4: A, B, C, D C, D, E, F Species turnover between community 1&2 is 4 species, between 1&3 is 0 species, between 1&4 is 2 species

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