LECTURE 9 - SPECIES RICHNESS Flashcards
What is biodiversity?
composition
-> species
-> genetic
-> community
Function
-> ecological }interactive ecological maps
-> evolutionary process } Alow for adaptatons
Why is species richness decreaseing?
- habitat loss
- degregation
- exploitation
- invasive species
- climate change
- —- all play apart in eachother
How to calculate species richness
count the number of species
The equation for the Shannon Diversity index
= sum(proportionOfSpeces{p}*lnp) *-1
calculate the Shannon DIversity: 40 trees of 3 species: 10 individuals of species A 5 individuals of species B 25 individuals of species C
um….. just try?
What is species evenness?
How distributed the species is.
H/ln(species richness)
Spacial surveying of diversity leads to
alpha, beta and gamma diversity
G-> regional total diversity
a -> measues it at a local scale (# in that site)
b-> measures diversity between locations local and regional scale
use of simple species richness modelling
r = total resources n = nich, what the individuals use o = overlap between species } where they use the same recourses
what models high species richness?
- > high overlap
- > many recourses (or high productivity)
- > High resource saturation
Energy vs species richness
higher temp, faster metabolizing, less cold damage + higher species richness
prediteration vs species richness
can inc (starfish halting lower trophic level competition) or dec (golden eagles on Santa Cruz)
disturbance vs species richness
kinda outta date… moderate disturbances are not conclusive to higher diversity
The equilibrium theory of island biogeography
compares rate of extinction vs rate of colonization of islands
->higher diversity with big islands close to the mainland
biodiversity gradients are caused by
- > more direct energy (near teh tropics)
- > less seasonality, more diversity
- > if the area is evolutionary older
