Lecture 17 Flashcards
Trophic cascade
“the indirect effects in which a change in the abundance or behaviour of one species cascades through the food web, influencing the abundance or behaviour of other species at different trophic levels”
Top-down cascade
- consumers regulate the abundance of prey species
- influence abundance of lower trophic levels
Bottom-up cascade
- availability of resources influence the abundance of consumers
- affect higher trophic levels
Keystone species
“a disproportionately large impact on its environment relative to its abundance or biomass”
Generic formula to measure strength of indirect effects (density)
(#Bcontrol - #Btreatment) / #Bcontrol
Keystone species
“a disproportionately large impact on its environment relative to its abundance or biomass”
Dominant species
“an abundant species that exerts significant influence on other species within that community or the structure and function of an ecosystem”
Ecosystem engineer
“significantly modifies or creates habitat, thereby directly or indirectly affecting the availability of resources for other species”
Foundation species
“provide the physical foundation of infrastructure for a community or ecosystem”
Compartments
“relatively isolated food web subsystems that are richly connected within the subsystem but are loosely connected between subsystems”
What are the patterns/trends of compartments in a food web?
Strong interactions WITHIN compartments
Weak interactions BETWEEN compartments
Module/motif
“subset of species within a larger food web that are interconnected by their feeding relationships”
Generalist
- A consumer that can make use of a variety of different resources
- i.e. lots of links.
- Flexibility is useful when facing variable environmental conditions.
Habitat coupling
“linking of discrete habitats are connected through the movement and foraging of mobile consumers”
Food web rewiring
“Fundamental changes in the structure of a food web that alter the pathways of nutrients and/or energy in an ecosystem” (reorganization)
