Biodiversity I: meaning and measurement Bio 415/615

Questions 1.What are the major components of ‘biodiversity’ as broadly defined? 2.What is species evenness, and how is it different from species richness? 3.How is the concept of biodiversity related to the science of phylogenetics? 4.How do alpha and beta diversity differ? 5.What role do keystone species play in ecosystems?

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

Defining Biodiversity Definitions…measurement…monitoring

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

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

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

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."

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

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

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)

Noss 1990 SCALE as integral to biodiversity concepts

Species, MUs, and ESUs Species concepts –Morphological –Biological –Phylogenetic MUs=Management units ESUs=Evolutionarily significant units

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

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

Cladistics / Phylogenetics

Integrated molecular tools to quantify biodiversity Taxonomy-free! Phylogeny Identity: DNA barcodes Individual variation

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

Types of species for conservation Indicators Keystones Umbrellas Flagships Vulnerables Foundation

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

Indicator species Hastings and Turner, The Changing Mile Carnegia gigantea

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

Trophic Cascade

Urchin barren: no kelp!

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

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

‘Foundational’ ‘Ecosystem Engineers – Transformers’

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

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

Which has the highest diversity? 5 monkeys5 herons 5 lions5 cows 5 frogs 1 monkey18 herons 2 lions2 cows 1 frog1 reptile Community 1Community 2

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

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

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)

Community with 10 frogs, 7 rats, 4 chipmunks, 2 mice 1234 Rank by abundance Abundance Rank-abundance Graph

889 oak trees, 100 bay trees, 10 maple trees, 1 birch tree 1234 Rank by abundance % of individuals A more realistic distribution of abundance generally requires a log scale

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?

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!

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

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