Question

case study #3
hurricanes can have a huge impact on the environment. many animals may be killed or have their habitat destroyed by intense winds and rainfall. in 1999, hurricane hugo reduced the puerto rican parrots population to half its size.

1. what was the limiting factor in this scenario?
2. will this likely be a constant factor for the parrot population?
3. what are other ways species might be limited by weather?

different kinds of limiting factors
some limiting factors depend on the size of the population in question. for example, in the first case study, the number of fish is only a limiting factor when the bear population reaches a certain size. therefore, the amount of fish can be considered a density - dependent limiting factor. other factors will have an effect on populations no matter what their current size is. for example, the hurricane in the third case study would have affected the parrot population whether it was large or small. therefore, weather is often considered a density independent limiting factor.
for each of the following limiting factors, determine if they are density dependent or independent.

1. food: with a limited amount of food available, a population will be forced to stop growing.

dependent or independent? why?

1. altitude: many species cannot live at high altitudes due to the lack of oxygen and extreme cold.

dependent or independent? why?

Explanation:

1. The limiting factor was the hurricane as it destroyed the habitat and reduced the parrot population.
2. It is unlikely to be a constant factor as hurricanes are not a continuous occurrence.
3. Species can be limited by weather - related events like droughts reducing water sources, or extreme cold killing off individuals.
4. Food is density - dependent because as population size increases, competition for limited food grows.
5. Altitude is density - independent as it affects species regardless of population size due to inherent environmental conditions like lack of oxygen and cold.

Answer:

1. Hurricane
2. No
3. Droughts reducing water sources, extreme cold killing individuals
4. Dependent; As population size increases, competition for limited food grows.
5. Independent; Affects species regardless of population size due to environmental conditions.