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(a) (b)

FIGURE 8.2 Species diversity and ecosystems. (a) Natural forests contain a high diversity of
tree species. (b) In forest plantations, in which a single tree species has been planted for lumber
and paper products, species diversity is low. (a: Paul Biggins/Alamy Stock Photo; b: Brent Waltermire/Alamy)

We can see this pattern in the number of bird species the area including oak woodlands, chaparral, deserts, urban
living along streams that differ in depth and the types of environments, and the ocean.
plants that are present along the shoreline. When researchers
examine the number of bird species living along 27 streams
in Vermont that supply water to Lake Champlain, they found ®
that the average stream contained only 17 species of birds, AP Exam Tip
but the entire collection of streams contained 101 species
of birds. The reason is that different types of birds preferred You are required to show all work for math problems
®
streams with different habitats. For example, fish-eating birds on the AP Environmental Science Exam. You will not
congregated at deeper streams that have very little agricul- get full credit for a correct answer unless you show
ture along the shoreline, wading birds congregated in shal- each step, no matter how simple. Remember to include
low streams, and insect-eating birds congregated in streams units. Develop the habit of showing your work from the
surrounded by meadows and forests. Having a diverse suite beginning of the year, starting with the math practice in
of habitats is therefore important to maintaining a high this module.
diversity of species.

Ecosystem Diversity

Species diversity The number of species in a region or in a

At the largest scale, we can think of ecosystem diversity , particular ecosystem.

which is the variety of ecosystems that exist in a given Habitat diversity The variety of habitats that exist in a given

region. For example, along the coasts of China, we can find ecosystem.

a mixture of temperate forest ecosystems, river ecosystems, Specialists Species that only live under a narrow range of
and the ocean ecosystem. As we saw in the case of habitat biotic or abiotic conditions.

diversity, a larger diversity of different ecosystems allows for Generalists Species that can live under a wide range of
biotic or abiotic conditions.

more species to live in a given area. Similarly, Los Angeles

County in California has the highest diversity of birds in Ecosystem diversity The variety of ecosystems that exist in
a given region.

the United States as a result of the many different habitats in
ModUle 8 ■ Introduction to Biodiversity 99
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