Cresswell's Reading Flashcards
What is an indirect interaction?
The impact of one organism/species on another that is mediated or transmitted by a third.
Give two possible ways that indirect interaction can occur.
- Interaction chain; a donor species affects the abundance of the transmitter, which has an effect on the recipient.
- Interaction modification; donor species alters another aspect of the transmitter, such as behaviour.
Give an example of interaction chain.
Bird species aggressively preys on caterpillar, which increases abundance of the plant the caterpillar was consuming.
Give an example of interaction modification.
Dragonfly nymphs prey on nymphs from different species, if given common prey species nymph prey will alter its behaviour to avoid being caught by other, reducing mortality rate of shared prey item.
What is a trophic cascade?
Ecological phenomenon triggered by the addition or removal of top predators, and involving reciprocal changes in the relative populations of predators and prey through the food chain, often resulting in dramatic changes in ecosystem structure and nutrient cycling.
What is Paine 1992’s report about?
The first experimental study designed to estimate interaction strengths in a species rich herbivore guild.
Give the model used in Paine 1992’s report.
Jacobian matrix; list summarising pairwise interaction strengths in a community.
Describe the results from Paine 1992.
- As rank of herbivore species increases, interaction strength with brown alga sporelings decreases.
What is the aim of Wooton and Emerson 2005 paper?
To locate an up-to-date view on whether communities are highly interactive.
Why do Wooton and Emerson say that measuring interaction strength is difficult?
Because of the large number of interactions in any natural system.
What are the study results from William et. al?
For species within large communities, they are on average two links apart, with more than 95% of species within three links of each other.
What is characteristic path length (William et al)?
The average number of links necessary for information or an effect to propagate along the shortest paths between nodes in a network.
What are Crawley and Harral interested in?
Whether there is an ecological regularity in species-area relationships.
What were the results of Crawley and Harral’s paper?
- Slope of log-log plot varies from habitat to habitat at same spatial scale
- slope of z=0.25 could not be global.
Summarise the main objective of Kaiser-Bunbury et al’s paper.
Used two qualitative and quantitative pollination networks to simulate extinction patterns following three removal scenarios: random and interactive removal of strongest and weakest interactors.
