Population Dynamics of Predation Flashcards
Two components of LV model…
N being numbers of prey
P being predator population
LV Model
Prey are removed depending on prey/predator encountering then removal by searching/attacking efficiency of predator
LV Equations…
dN/dt=rN-aPN
dP-dt=-qP
dP/dt=faPN-qP
Derive LV model…
a is efficiency of searching/killing
q is predator mortality rate
Derive dP/dt-faPN-qP
aPN describes rate at which food is consumed
f is predator efficiency
What does faPN-qP describe?
Predator mortality depends on consumption rate and effiency of turning food into offspring
Zero Isoclines
Describes equilibrium of population growth and decline of predator/prey population
What can zero isocliens be used for?
Look at properties of this model, graphically with prey density against predatory density
What do lines is ZI show?
Combinatiosn of predator/prey density leading to unchanging prey or predatory population, an isocline of each plotted on same figure
One side of isocline means population decrease whilst other increase
Examples of abundance patterns generated by prey/predator populations…
Stable-point Equilibra, multigeneration cycle, one-generation cycles, caos
Primary driver of abundance patterns…
Density dependence
Examples of patterns of consumption…
Higher consumption means quicker growth, develoment and birth, influencing migration/density dependence
Functional Response
Is the dependence of consumption rate on prey abundance, as a function of prey density
Type 1 FR
Linear increase in consumption rate with prey density
Type 2 FR
Limitation in consumption rate with prey density, that being a plateau proceeding icnreasing
Type 3 FR
Sigmoidal curve with beginning of curve experiencing acceleration, predator interest in prey when density at certain amount, similar plateau with handling time
Mast Years
Large amounts of reproduction in specific years with low amounts of reproduction in between
Importance of mast years in plants…
Bypass excessive predation, due to satiation, low-densities, slow expansion unable to exploit
Cicadas in mast years…
Prime numbers of 13 or 17 years, with rapid abundance, hatch in oviposit in cnaopies, predators cannot track
How is predation influenced by intra/inter comp?
Mutual interference limit consumption rate of predators, even if prey not limited
Exampels of comp altering LV dynamics…
THe more competitors the more one defens resource, or prey intimidated by predators
Examples of zero isocline density in interference…
Low densities assume no intra comp, thus horizontal isocline, where intra comp increases with prey density
Mutual Interference
This is when access to resources is negatively affected by presence of other individuals
What creates a carrying capacity?
High densities and resource competition
Population dynamics of Type 3 FR
Prey at low densities increase in abundance regardless of predator density, which can be stable if predator acn maintain themselves at low densities
Contradict idea of type 3 response, ignoring prey at low densities
Population dynamics of Type 2 FR…
Zero isocline rise as prey density increases if predator plateaus at low prey density, due to prey insufficiency with following fall with prey competition
Why might patchiness influence foraging…
Differ in prey densities or description of a patch dependent on size of predator
Marginal Value Theorem
Model descriing behaviour of an optimally foraging indivdual in systems where resources are located in discrete patches between areas with no resoruces
Examples of PD heterogeneraity…
Snails within cracks, away from predator birds, thus vertical zero isocline at low prey abudnance
