Week 10 Monday Flashcards
whats a community?
association of interacting species in a defined area
what attributes can a communitys structure be described with?
- Number of species
- Relative abundance of species
-Kinds of species present
what shape are species abundance curves?
bell shaped - log normal
what 2 factors is species diversity a function of?
- Species richness
- Species Evenness ( a measure of relative abundance)
Alpha diversity?
measure of local diversity
Gamma diversity
measure of regional or landscape diversity
Beta diversity
measure of difference among communities within a landscape so gamma/alpha.
species evenness calc
peilous is J, shannon weiner over hmax.hmax is shannon wiener over ln s (species rich)
when does evenness increase?
when j approaches 1
what is a rank abundance curve?
plot of relative abundance of species against their rank in abundance
how does environmental complexity affect spcies diversity?
increases it
why is the species richness and diversity higher near the equator?
- increased habitat heterogeneity
- more competition
- stable climates
- predation is intense
- communities are old, creating more opportunities for diversification
why does biodiversity matter?
- ecosystem function depends on community structure
- ecosystems provide ecosystem services - processes and resources that are valued by humans
- biodiversity enhances ecosystem productivity
biodiversity matter pt2?
- Complementarity
- Facilitation
- Sampling Effect
what is complementarity?
species with certain niches would only be able to exploit that niche space even if there is more space and exploited ecosystems offer enhanced function
