Chapter 18, Community Structure in Space: Biodiversity Video Solutions, Ecology : The Experimental Analysis of Distribution and Abundance

Problem 1

The tree flora of Europe is less diverse compared with that of eastern North America or eastern Asia (Grubb 1987 ). Why should this be? Compare your explanations with those of Grubb (1987) and of Currie and Paquin (1987).

Rikhil Makwana

Numerade Educator

02:05

Problem 2

Hydrothermal vents are like geysers in the deep ocean on the seafloor. They continuously spew super-hot, mineral-rich water that helps support a diverse community of organisms. Vents are typically $2-100 \mathrm{km}$ apart on the ocean floor, and in the Pacific exist for $10-100$ years before they collapse. How could you test the intermediate disturbance hypothesis for these vents? Tsurumi (2003) discusses diversity at hydrothermal vents in the Pacific Ocean.

Shital Rijal

Numerade Educator

01:38

Problem 3

Marine algae along the west coast of North America do not increase in species richness toward the tropics but peak at about 70 species per $100 \mathrm{km}$ of coastline around $40^{\circ} \mathrm{N}$ latitude (Gaines and Lubchenco 1982 ). Along the east coast of North America, species richness gradually increases as you move toward the tropics. Discuss why these patterns might hold.

Angela Deane

Numerade Educator

03:01

Problem 4

In analyzing the role of fire as a disturbance in tallgrass prairie, Collins et al. (1995) found that the intermediate disturbance hypothesis was supported if, instead of plotting fire frequency as in Figure $25 \mathrm{b},$ they plotted time since the last fire on the $x$ -axis. Why should they get different results for these two plots of the same data?

Sheryl Ezze

Numerade Educator

01:50

Problem 5

Would you expect to have latitudinal gradients in the species richness of macroparasites of mammals and birds? What factors might control species richness in macro-and microparasites?

Zachary Papazian

Numerade Educator

01:33

Problem 6

The merits of neutral theory in ecology are not clear to many ecologists yet they remain a powerful method to utilize in model building (Bell 2000; Alonso et al. 2006 ). Discuss the value of neutral models and in particular whether there is only one type of neutral model for a particular question like global biodiversity abundance patterns.

Courtney Burson

Numerade Educator

01:44

Problem 7

The longest experiment in ecology is the Park Grass Experiment begun in 1856 at Rothamsted, England. A mowed pasture was divided into 20 plots, and a series of plots were fertilized annually with a variety of nutrients, including nitrogen. Discuss the predictions you would make regarding biodiversity on fertilized and unfertilized plots for this experiment, using the six factors discussed in this chapter. Silvertown et al.
(2006) give the observed results.

Sam James

Numerade Educator

00:14

Problem 8

In Antarctica, species richness in soft-bottom invertebrates (sponges, bryozoans, polychaetes, and amphipods) is higher than that of almost all other tropical- and temperate-zone soft-bottom communities (Clarke 1990 ). What observations or experiments would you perform to find out why this high biodiversity occurs in Antarctica?

Emily Marty

Numerade Educator

00:50

Problem 9

Figure 20 shows that, on a global scale, species richness increases smoothly with solar energy and temperature. Why should this occur? Why is the available energy not monopolized by a few superspecies? Compare your ideas with those of Currie $(1991, \mathrm{p} .46)$.

Sanjeev Kumar

Numerade Educator

03:04

Problem 10

The evolutionary speed hypothesis has been tested with genetic marker data in only one group, birds (Bromham and Cardillo 2003 ). They found no evidence in favor of a higher rate of speciation in tropical areas for birds. Discuss how this finding would change the interpretation of the evolutionary speed hypothesis (e.g., Figure 11 ) if similar results are found in many other taxonomic groups. Are these data sufficient to reject the evolutionary speed hypothesis?

James Thierer

Numerade Educator

01:10

Problem 11

Does the Janzen-Connell hypothesis for diversity maintenance in tropical rain forests imply that mortality in small trees should be density dependent? Describe an experimental design (including the time frame required $)$ that would allow you to test this hypothesis. Read Hyatt et al. (2003) and discuss whether their data are sufficient to reject the JanzenConnell model for most forest systems.

April Berlyoung

Numerade Educator