Questions: 25. Prior to 1960, the winter food sources in the marshes controlled the growth of the snow goose population. The available supply of reeds, roots, and tubers in the marshes was a. an example of a community of climax species b. an example of a community of pioneer species c. a density-dependent limiting factor for snow geese d. a density-independent limiting factor for snow geese 26. Given a further increase in the snow goose population, in the Churchill, Manitoba nesting area a. interspecific competition will increase because of decreased species diversity b. interspecific competition will increase and intraspecific competition will decrease c. intraspecific competition will increase because available food supplies are decreasing d. intraspecific competition will decrease because fewer snow geese will be able to find nesting sites

25. The answer is c: a density-dependent limiting factor for snow geese.

• a. an example of a community of climax species: Climax species are those that appear in the final stage of succession, forming a stable ecosystem. The food sources (reeds, roots, and tubers) are not climax species; they are part of the ecosystem that supports the snow geese.
• b. an example of a community of pioneer species: Pioneer species are the first to colonize a barren environment. The marshes with reeds, roots, and tubers are not pioneer species; they are part of an established ecosystem.
• c. a density-dependent limiting factor for snow geese: This is correct because the availability of food sources like reeds, roots, and tubers in the marshes would limit the snow goose population based on their density. As the population increases, the competition for these resources would also increase, thus controlling the population growth.
• d. a density-independent limiting factor for snow geese: Density-independent factors affect populations regardless of their size, such as weather events. The food supply in the marshes is dependent on the population size, making it a density-dependent factor.

26. The answer is c: intraspecific competition will increase because available food supplies are decreasing.

• a. interspecific competition will increase because of decreased species diversity: While decreased species diversity can lead to increased interspecific competition, the question focuses on the snow goose population, which is more directly affected by intraspecific competition due to limited resources.
• b. interspecific competition will increase and intraspecific competition will decrease: This is incorrect because as the snow goose population increases, competition among the same species (intraspecific) for limited resources will also increase.
• c. intraspecific competition will increase because available food supplies are decreasing: This is correct. As the snow goose population grows, the competition among individuals of the same species for limited food and nesting sites will increase.
• d. intraspecific competition will decrease because fewer snow geese will be able to find nesting sites: This is incorrect. Fewer nesting sites would actually increase intraspecific competition as individuals compete for the limited available resources.

In summary, the growth of the snow goose population is controlled by density-dependent factors such as food availability, and as the population increases, intraspecific competition for resources will also increase.