Lecture 2 What is species diversity?

How can species be grouped?

• Morphology: look similar/different

• Biology: Can breed/not breed

• Evolutionary: similar DNA

• Indigenous: ecology, use

• Pros and cons to each approach

• Difficulties identifying species affects

What is Biodiversity?

The complete range of species and biological communities on Earth, including genetic

variation within those species and all ecosystem processes e.g. Species diversity, Genetic diversity, Ecosystem diversity, Global biodiversity

What is Alpha, Beta and Gamma Diversity?

R.H. Whittaker (1960) proposed that the total species diversity in a landscape is determined by 2 things:

1. mean species diversity at local scale (sites or habitats)

2. the differentiation among those habitats

What is Alpha Diversity ( α )?

Diversity at a local scale

Number of species in a community e.g. lake or meadow

What is Gamma Diversity ( γ )?

Diversity at a regional scale

Number of species at larger scale e.g. mountain

What is Beta Diversity ( β = γ / α )?

Ratio of species between the local and regional scale

High Beta diversity generally indicates presence of rare species, and high species turnover

Which area would you protect the most?

One where Alpha is the highest = highest biodiversity (on slide)

What is Species richness?

Number of species

What is Species evenness?

Relative abundance of a species

What is Shannon - Wienner Diversity Index?

Shannon Diversity Index takes into account the abundance of organisms in each species

p = proportion of each species i

What does species diversity take into account?

Species richness and Species evenness

Why does rarity happen in some species?

• Normally exist at very low population densities (e.g.Wolverines (Gulo gulo))

• Size, competition and territoriality play a role

• Associated with uncommon habitats (e.g. patches of recently burned forest - resprouting ability).

• Localized range (e.g. Vancouver Island marmot) - Endemic

What is an Endemic?

A species is only found in one location