Essentials of Ecology

SUPPLEMENT 9 S57

StarflowerStarflower

BacteriaBacteria BunchberryBunchberry

FungiFungi

SnowshoeSnowshoe

harehare

Pine sawyerPine sawyer

beetle and larvaebeetle and larvae

WhiteWhite

sprucespruce

WolfWolf

BebbBebb

willowwillow

GreatGreat

hornedhorned

owlowl

Balsam firBalsam fir

MooseMoose

Blue jayBlue jay

MartenMarten

Producer

to primary

consumer

Primary

to secondary

consumer

Secondary to

higher-level

consumer

All producers and

consumers to

decomposers

Starflower

Bacteria Bunchberry

Fungi

Snowshoe

hare

Pine sawyer

beetle and larvae

White

spruce

Marten

Wolf

Bebb

willow

Great

horned

owl

Balsam fir

Moose

Blue jay

Figure 5 Some components and interactions in an

evergreen coniferous (boreal or taiga) forest ecosys-

tem. When these organisms die, decomposers break

down their organic matter into minerals that plants

use. Colored arrows indicate transfers of matter and

energy among producers, primary consumers (her-

bivores), secondary or higher-level consumers (carni-

vores), and decomposers. Organisms are not drawn

to scale. Question: What species might increase

and what species might decrease in population size

if the great horned owl were eliminated from this

ecosystem?