Question

A biologist studying alpine wildflowers notices that two populations of similar species are able to occupy the same niches. However, species A is mostly found at lower altitudes, while species B is mostly found at higher altitudes. What has most likely caused the realized niches of these two wildflower populations to be smaller than their fundamental niches?

Answer 1

The answer is resource partitioning. Due to competition between the two species population,  the two species evolved to utilize different resources. Therefore, this is rather than competitive exclusion that results to the out-competition of one species, or competition that results in a negative interaction between the species.  

Answer 2

Answer:

A fundamental niche represents the set of environmental conditions in which a species can survive and reproduce. A realized niche represents the environmental factors actually utilize by the species in order to survive after interaction with predatory and competing species. Here, the two species A and B are able to occupy the same niche that is they are able to live in fundamental nich but they acquire different locations for their survival that is lower and higher altitudes.  

The species acquiring different habitat is their choice but there are some factors which are limiting their growth and abundance in the realized niches for example resources and predation.