Essentials of Ecology

CONCEPT 7-2 155

and abundant precipitation, often spread fairly evenly

throughout the year (Figure 7-15, center graph).
This biome is dominated by a few species of broad-

leaf deciduous trees such as oak, hickory, maple, poplar,
and beech. They survive cold winters by dropping their

leaves in the fall and becoming dormant through the

winter (see Photo 4 in the Detailed Contents). Each
spring, they grow new leaves whose colors change

in the fall into an array of reds and golds before the
leaves drop.

Because of a slow rate of decomposition, these for-
ests accumulate a thick layer of slowly decaying leaf

litter, which is a storehouse of nutrients. (Figure 4,

p. S56, in Supplement 9, shows some components and
food web interactions in a temperate deciduous forest

ecosystem.) On a global basis, this biome has been dis-
turbed by human activity more than any other terres-

trial biome. Many forests have been cleared for grow-

ing crops or developing urban areas. However, within

100–200 years, abandoned cropland can return to a de-

ciduous forest through secondary ecological succession

(Figure 5-17, p. 117).

The temperate deciduous forests of the eastern

United States were once home to such large predators

as bears, wolves, foxes, wildcats, and mountain lions

(pumas). Today, most of the predators have been killed

or displaced, and the dominant mammal species often

is the white-tailed deer (Case Study, p. 114), along

with smaller mammals such as squirrels, rabbits, opos-

sums, raccoons, and mice.

Warblers, robins, and other bird species migrate

to these forests during the summer to feed and breed.

Many of these species are declining in numbers because

of loss or fragmentation of their summer and winter

habitats.

Evergreen coniferous forests (Figure 7-15, bottom

photo) are also called boreal forests and taigas (“TIE-

guhs”). These cold forests are found just south of the

Harpy

eagle

Ocelot

Squirrel

monkeys

Katydid

Green tree snake

Tree frog

Bacteria Bromeliad

Fungi

Ants

Slaty-tailed

trogon

Climbing

monstera palm

Blue and

gold macaw

Harpy

eagle

Producer

to primary

consumer

Primary

to secondary

consumer

Secondary to

higher-level

consumer

All producers and

consumers to

decomposers

Ocelot

Squirrel

monkeys

Katydid

Green tree snake

Tree frog

Bacteria Bromeliad

Fungi

Ants

Slaty-tailed

trogon

Climbing

monstera palm

Blue and

gold macaw

Active Figure 7-16 Some com-

ponents and interactions in a tropical rain forest

ecosystem. When these organisms die, decomposers

break down their organic matter into minerals that

plants use. Colored arrows indicate transfers of matter

and energy between producers; primary consumers

(herbivores); secondary, or higher-level, consumers

(carnivores); and decomposers. Organisms are not

drawn to scale. See an animation based on this figure

at CengageNOW.