Landscape ecology Flashcards
What did Alfred Russel Wallace do in 1984?
Wrote a letter to a friend observing different species compositions on different islands, divided by what is now called “wallace’s line”. He proposed 6 different geographical regions.
Why are island population distinct?
They have fewer species and different selection pressure (predation/competition) - smaller gene pool
What is the founder effect
The loss of genetic variation when a population is reduced
Describe the island effect
Smaller organisms are larger and larger organisms are smaller on island
Describe the species-area relationship
number of species = c(area of island)^z where c and z are constants
Describe the equilibrium model of island biogeography
immigration rate and extinction rate work at equilibrium with the number of insular species (species equilibrium)
How did they test the equilibrium model of island biogeography?
use a number of small islands created by mangroves in florida and sprayed everything, starting at 0 species to record the speed the islands are colonised with varying distance from the mainland.
What does a high z-value mean?
rapid increase of species richness with area
What does a low z-value mean?
gradual increase of species richness with area
What is a meta-analysis?
a set of statistical tools allowing you to pol together results of a number of studies to standardise in a single observation.
How does body size effect the species-area relationship?
SAR is steeper with bigger bodies
Define ‘landscape’
an area that is spactially hetergeneous in one factor of interest
Define ‘landscape ecology’
the study of landscapes, taking accound of the ecology of the biological population
What is the normal state of a landscape?
non-equilibirum
What is a matrix
the area surrounding a suitable habitat
Describe the 4 types of disturbances within a landscape
shrinkage, bisection, performation (holes in habitat), fragmentation
Give 2 factors describing the scale of a studied habitat
grain (resolution) and extent (overall size of area)
How does fragmentation in a habitat effect its population?
lower species richness in fragmented habitat, with migration between fragments dependant on matrix suitability. Smaller fragments = fewer species = larger number of extinctions.
Describe the edge effect in fragmented habitats
an ecological trap (organisms may be induced to settle in a low quality habitat) due to following cues which have been distrupted
Give an example of a species found in an ecological trap
indigo bunting in south carolina
