#Prey vs predator population graph Patch#

Sometimes clearly not, other times they appear to be tightly linked. Thus far we have considered population models which show how populations can be limited by resources (intraspecific interactions) and how interspecific competition can affect population size. The population dynamics of predator/prey interactions. Duration of stay longer when travelling time between patches is longer.We assume rate of extraction same in habitats – extraction curves are parallel Graph 5 High productivity vs Low productivity Productive habitats and shorter in less productive ones.

#Prey vs predator population graph Patch#

Duration in the patch should be longer in more.

Some predictions generated from the marginal value theorem. Graph 3 - Cumulative energy extracted (CEE) over time To maximize rate of energy extracted from the patch it will be a function of : cumulative energy extracted(CEE)/ time. To forage optimally it must maximize it’s rate of energy intake not merely for its period in the patch but for the entire period since its departure from the last patch – period t t + S, S= duration in the patch. Graph 2: Forager arrives in average patch: t t is the length of time a forager can expect to spend on average after leaving a patch before finding another. average time spent travelling between patches is is t t. food is distributed patchily some patches more valuable than others. Question: At what point should forager leave patch?Īlways moving, little time spent feeding. Shape of curves are dependent on productively and foraging efficiency (i.e. Cumulative energy extracted vs rate of extraction. Movement between patches assumes energy intake will be zero. In doing so, it will maximize the average rate of energy intake for the bout as a whole. Optimum residence time will maximize it’s overall energy intake during a bout of foraging. Question: When should the decision to switch to another patch occur? bees feeding on flower nectar, insectivorous birds) predator should leave to find another patch.

As patch quality changes due to resource depletion (e.g. In general: consumer (predator) should spend more time in higher profitable patches. Model referred to as Optimal Patch Theory or Marginal Value Theorem. The model describes how long a predator should spend foraging in a patch. We can add another level of complexity to understanding patterns of foraging among predators.ĭefine patch as : a discrete habitat or object where prey is distributed somewhat uniformly and separated from other prey which occur in other patches.Īgain, another model by Charnov (1976), developed to describe the movement of predator from one patch to another.