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Chapter 26: Community Ecology (Metapopulations in Patchy Environments #,…
Chapter 26: Community Ecology
Diversity
Checklists used to quantify species present
Diversity and Scale
Scale matters
Species-area relationships: S=cA^z
A=Area
S= number of species
c and z are constants that must be discovered
Alpha, Beta, and Gamma diversity
Alpha= number of species that occur at a local small site
Beta diversity compares differences between several small sites within a larger region
Gamma diversity is the number of species within a region.
Species abundance distribution
https://www.coursera.org/lecture/biological-diversity/4-3-curves-of-biodiversity-Pnyke
Diversity and Latittude
Diversity is greater in areas of moderate latitude and lesser in ares of extreme latitude
Biomes created by latitude lines naturally
Predator-Prey Interactions
One Predator, One Prey
This model is useful because it helps us understand how human predators should harvest our various prey
Graph
Two fundamental aspects
Feeding rate
Handling time
The sum of these two are referred to as the predator's functional response
Prey- dependent
Lotka-Volterra model
#
models the net rate of change in prey numbers
dN/dt=rN-aNP
Rate of change with the time of prey population
Criticized for being too simplistic
Main value is the ability to simplify complex interactions while teaching the fundamentals of predator-prey relationships
Paradox of enrichment
Maximum sustained yield
fixed effort harvesting
fixed quota harvesting
https://www.youtube.com/watch?v=DO2aM08WHy0
Competition between species
Inter-species competition
Exploitation competition
Interference competition
Invasive species
Resources
Any substance or factor that can lead to increased growth rates as its availability is increased
Apparent Competition
Beneficial Interactions Between Species
Mutualism
Both species benefit
Mycorizzhae and roots
Facilitation
One species benefits, the other is neutrally or negligibly effected
Beavers building dams
Nurse plants
Primary succession
Interconnectedness of Species: Food Chains and Food Webs
#
Food chain
food web
energy flow diagram
Keystone species
https://www.youtube.com/watch?v=CZhE2p46vJk
Metapopulations in Patchy Environments
#
If several local populations are interconnected by migration and gene flow between patches, the local populations constitute a metapopulation
four assumptions in common model of metapopulations
1) A region of the environment is composed of many discrete patches in which the species can live
2) Some patches are occupied by the species whereas other suitable patches are not
3) Empty patches will become colonized by migration from occupied patches
4) Populations within individual patches have a probability of going extinct within that patch
High quality patch= source habitat
Low quality patch= sink habitat
