Question

1. Describe the Ideal Free Distribution Model. What does it predict? Provide an example. What other considerations might this model need to include to improve its accuracy?
2. Selecting a territory can be a decision-making process. List some of the costs and benefits of territory ownership. How can animals help reduce costs of owning a territory? (Hint: your book mentions, learning, satellites and kinship)
3. Migration is the obligate movement of one geographic area to another. Imagine you are a migratory animal… What kind of animal are you? Where are you going? How are you navigating your route? And what are some of the things you might be considering during your journey?

Answer 1

Answer: Ideal free distribution (IFD) model is the theoretical model of competitors distribution between habitat patches. It states that, if the amount of resources is more in a particular habitat, the number of individual animals will be more and vice versa. It predicts that the distribution of animal individual among resource patches will minimize intra- and inter-specific competition which will maximize fitness. Animals forage in highest quality resource patch.

To improve its accuracy, this model needs to include the degree of variance in the resource supply rate, habitat fragmentation and the uncertainty of information for decision making (animal behaviour). If the habitat is fragmented, the species density will be lesser than predicted by the IFD model.

A competitor may decide to choose a resource patch based on the information on the distribution of competitor, the resource supply rate and the intake rate of the competitor in the specific habitat. The benefits of territory ownership are sufficiency of resources (highest resource intake) and less competition. There is a benefit if the resources are in continuous input condition, but if there is random supply, then that could cost the animal. There could be depletion in the resources in a particular patch. If the competitor knows its food gain but has no knowledge of the rate of competitor intake then that could also cost. Because even if there is sufficient resource and one of the competitors has a higher rate of consumption, then that could lead to resource insufficient which may cost one of the competitors. Fragmented habitat leads to more migration. Migration for resources is a cost. Higher the migration rate, higher is the cost and mortality.

Migration is the obligate movement of one geographic area to another. I am a bird. I am going to the temperate region. I am navigating the route by sensing the atmospheric temperature, earth’s magnetic field, observing the sun and stars and memory. The things that I will consider during my journey is to sense if there are variations in the atmosphere and weather. This will confuse the route. This is a need for a brief halt for some time till the variations are stabilized. I have to be cautious for predation and hunting during the migration.