Use the following information to answer the next three questions
From 1968 to 1990, the population of snow geese nesting near
Churchill, Manitoba, increased from about 3 000 pairs (6 000
individuals) to about 24 000 pairs (48 000 individuals) with a
nesting density of around 1 000 nests per square mile. Snow
geese winter along the coasts of Texas and Louisiana. Prior to
1960, marshes along these coasts provided the main food
sources (reeds, roots, and tubers) for the geese. Destruction of
these marshes and increased crop production of rice, corn, and
soybeans has occurred since that time. The stubble from these
crops and spilled grains are easily obtained food sources for the
snow geese. Reduction in hunting and greatly increased food
supplies from cultivation near their wintering ground has cut
mortality rates of snow geese in half over this period.
The high nesting density of the snow geese has left little foraging
or nesting space for other species of birds, and a decline in
several duck species and shore birds has been observed.
Simultaneously, intensive foraging by the snow geese erodes and
dries out patches of Arctic soil, reduces regrowth of grasses and
sedges, and greatly increases soil salinity
15. Based on the information provided, what is the per capita
growth rate of the snow goose population between 1968 and
1990?
(Record your answer in the numerical-response section below.)
Your answer:
16. 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
an example of a community of pioneer species
a density-dependent limiting factor for snow geese
a density-independent limiting factor for snow geese
an example of a community of climax species
17. Based on the information provided, it would be reasonable to
conclude that the snow goose population
has a higher mortality than natality rate
has increased its biotic potential
has reached the carrying capacity of the ecosystem and
environmental resistance is decreasing
is in the growth phase and environmental resistance is
increasing
