In the past, preservation efforts usually focused on single species, such as polar bears or florida panthers. however, current preservation efforts generally focus on whole communities and ecosystems. one approach to the preservation of biodiversity on this scale is the establishment of protected areas such as natural parks and reserves. marine reserves are protected areas in the ocean where harvesting fish and invertebrates is limited or prohibited. generally, these reserves protect a coral reef ecosystem, a kelp forest ecosystem, or an area near a particular shoreline, rather than a single species. the following graphs represent changes typical after the establishment of some well-planned marine reserves. interpret the graphs and determine which of the following statements are true?
a. species diversity generally increases in marine reserves.
b. if lobster harvesting is prohibited in an area, sea urchin density would likely increase.
c. sea urchin density is higher in marine reserves, probably as a result of decreased collection by commercial divers.
d. although marine reserves predatory species such as sea otters and lobsters to thrive, there is only a slight effect on kelp.
e. an increase in the number of predators in a community correlates with a decrease in the number of grazers (sea urchins in this case).
f. organism size increased by about 30% after the establishment of this reserve.
g. kelp forest recovery in marine reserves is likely due to an increase in predators.
h. the density of all the organisms in an area can be expected to increase after the establishment of a reserve.
i. because reserves have a higher diversity of species, individuals of each species are, on average, smaller.