Answers to Figure Legend Questions

FIGURE 16.2 Based on the dates of Caulerpa sightings, it is likely the seaweed spread from Monaco west to Spain and east to Sicily, Italy, at about the same time (1992, 1993). It was restricted to these locations for 2 years, but then traveled to the eastern coast of Italy, and from there to the island of Hvar (1995), from which it spread to the northern islands of Croatia (1996).

FIGURE 16.3 The desert and hot springs communities are defined by physical attributes of their environment, whereas the kelp forest and coral reef communities are defined by biological attributes of their environment, particularly by the presence and importance of abundant species (i.e., kelp and corals, respectively).

FIGURE 16.10 The tropical soil bacterial community requires much more sampling because each sample contains new species, thus producing a linear species accumulation curve. The sampling in the temperate forest plant and tropical bird communities was sufficient to identify a large majority of the species in these communities, and thus more sampling would not be needed.

This is clear from the leveling off of the species accumulation curves once all the samples were analyzed. Finally, although the human oral bacterial and tropical moth communities showed some leveling off of their species accumulation curves, new species were being found even once all the samples were analyzed. Thus, they also need more sampling to adequately capture their species richness.

FIGURE 16.18 Beavers act as ecosystem engineers by damming streams with cut trees and woody debris. This behavior creates a flooded area, which accumulates sediment and eventually becomes dominated by marsh vegetation. At a landscape scale, by creating a mosaic of wetlands within a larger forest community, the beavers' actions enhance regional species diversity. Thus, beavers can also be classified as keystone species because they have such a large effect on diversity relative to their size and abundance.