Lecture Two - Biodiversity Flashcards
Give some symptoms of Sudden Oak Death.
- Bleeding or sapping from main stem or trunk
- Wilted shoots
- Bark beetle infestation
- Rapid change in foliage colour from green to brown
When was Sudden Oak Death first reported?
1995
Give the name of the agent causing Sudden Oak Death.
Phytophora ramorum
Describe the experiment conducted to assess the influence of Sudden Oak Death.
- Oaks removed from the landscape
- In Black Rock Forest, Cornwall, New York
Did the experimental removal of oaks affect the community?
Had a ripple effect into the community.
Several species linked to oaks; fungi, parasitoids, birds, scale insects.
Other than removal of oaks, describe another experiment conducted in Black Rock Forest.
Study on ant diversity and abundance between plots with oaks and plots without oaks.
Name three ways of collecting ants.
- Wrap up tuna and wait for ants to arrive
- Create pit fall traps with fairy liquid in a beaker in the ground
- Hunt with tweezers
How many species of ants were found in New York experiment?
Nine
Name the most abundant species of ant found in New York experiment.
Aphaenogaster rudis
What is the typical shape of a Rank-Abundance Diagram?
Lazy-J
What kind of diagram typically produces a Lazy-J shape?
Rank-Abundance Diagram
On a Rank-Abundance diagram, how can you assess the species richness?
Species richness is the number of bars on the RAD.
Give three reasons why bars on a RAD may not be even/some species are more abundant than others.
- Competition; species ‘1’ would be the strongest, and ‘9’ the weakest.
- Preference by predators
- Ease to catch by predators.
Give the three criteria for Rabinowitz’ rarity.
- Size of geographic range (large/small)
- Habitat specificity (generalised/specialised)
- Local population density
How many combinations of Rabinowitz rarity criteria are there?
Eight
According to Rabinowitz, how many ways are there to be common?
One
Name a species that is rare by all of Rabinowitz’ criteria.
Ivory-billed Woodpecker (Florida, USA)
Name an index that can be used to calculate species evenness.
Berger-Parker Index
Give the equation for the Berger-Parker Index.
1/max(Pi)
Pi = the proportion of individuals belonging to the most common species.
What would the BP diversity index be for even species abundance in 10 species?
10
What would the BP dominance index be for even species abundance in 10 species?
0.1
Give the equation for estimated number of species.
S(estimated) = S(observed) + S(undiscovered)
Describe the study conducted on species richness in the soil seed bank of Costa Rican rainforest in 1998.
- 34 different species found
- 121 soil samples
- 952 seedlings germinated
- Created Lazy-J shape
Describe the accumulation curve.
- Number of species discovered always increases with sampling effort
- Reaches a saturation point
- Find less new species the longer you collect individuals
How do you estimate the number of undiscovered species?
Extrapolate your accumulation curve to a flat line, and use your graph to estimate.
Give the equation for the number of undiscovered species, the Chao1 estimator.
S(undiscovered) = a^2 / 2b
a = number of species represented by single individuals (singletons) b = number of species represented by two individuals (doubletons)
When does Chao1 report no undiscovered species?
When the collection has no singletons (number of species represented by single individuals).
Describe a Species-Abundance Distribution.
- Every bar has an ‘abundance bin’ - a range of abundance.
- Each bar represents the number of species that met this abundance.
- Most species are of intermediate abundance.
- Curve = log-normal curve.
What comes before the 1st individual in the sample in a SAD diagram?
A hypothetical second half of the bell curve.
Species before this point are too rare for us to even catch one.
What is the name given to species too rare to catch in a Species Abundance Diagram?
‘Behind the veil’ species.
Give a model of community assembly.
MacArthur’s ‘broken stick’ model - breaking a stick randomly into pieces creates a Lazy J shape.
