Forests and their InteractionsAP Environmental Science

Types of Forests Any area where trees cover more than

10% of land. Includes:a. open savannas - < 20% ground coverb. Closed canopy forest – tree crowns

overlap to cover most of the ground.c. Primary forests: composed primarily of

native species

Reason why old forests are important?O.F. contain unique biological features w/: large live & dead trees a large variety of vegetation, insects

and animals species. Often home to rare species, threatened

species and endangered species of plants and animals, making themecologically significant.

Types of Forests-Old Growth

Other names include: 1. Virgin forests2. Primary forests3. Ancient forests4. Primevil forests

Old Growth Forests

New Growth Forests

New Growth forests

Deforestation & Consequences

Cause of deforestation? Logging industry Cattle ranching Farming Biofuel production Food production

(ie. palm oil)

Consequences!!

Erosion Water Runoff Excess CO2 Loss of

biodiversity Loss of cultural &

historic values

Forest Canopies Upper canopy Mid-canopy Lower Canopy http://www.canopyintheclouds.com/pano

s/elfinforest

Forest Fires Forest Fire Management Nova Fires by Month 2000

Forest Fires-Hot Question In Mediterranean climates like portions of

California, a wetter than normal winter often leads to greater severity of fires following summer. This paradox occurs because increased rain leads to…

A. Greater accumulation of chaparral biomass B. Higher pollination of annual flowers C. Greater recreational use of parklands D. Greater erosion & damage to access roads E. Decreased summer rainfall

Forest Protection Legislation1. Debt for Nature Swap2. Roadless Rule – Clinton Administration3. Northwest Forest Plan to regulate

harvesting on about 9.9 million ha of federal lands in Oregon, Washing and northern California.

Question to ponder? The largest area of old-growth forest in

the United States is located in:A. AlaskaB. B. MontanaC. CaliforniaD. North CarolinaE. Michigan

Forest and Competition There are several species interactions

within an ecosystem:

1. Competitive Exclusion Principle 2. Resource Partitioning 3. Ecological Niche

This type of interspecific competition:– may occur when 2 or more species in community

use similar resources & those resources are in short supply OR

- may limit the population growth of the competing species

Intraspecific Interactions– Relationships within the same species

Competition Between Species

Experiment #1: Russian ecologist G. F. Gause studied the effects of interspecific competition in two closely related species of protists called Paramecium.

What do these results tell you about the interaction of these 2 species?

1.

1. Competitive Exclusion Principle

P. aurelia

P. caudatum

Separate cultures

Combined cultures

From his research, Gause concluded that two species so similar that they compete for the same limiting resources cannot coexist in the same place for any length of time.

One species will always be more efficient and adaptable:….in getting food….in reproducing

• Ecologists called this concept the competitive exclusion principle

Ecological Niche:a. Sum total of a species’ use of biotic and abiotic resources in its environ &

b. A species’ habitat & it’s job (ex. Forest / producer)

• We can now restate the competitive exclusion principle as follows:

Two species cannot coexist in a community if their niches are identical.

Figure 19.7

A. ricordii

A. distichusA. aliniger

A. distichus

A. cybotes

A. ricordii

A. insolitus

A. christophei

A. etheridgei

A. christophei

A. etheridgei

A. cybotes

A. distichus

A. insolitus

Resource Partitioning-

Experiment #1: Explain this example of resource partitioning. How have the different species adapted to their competition?

A. insolitus

There are two possible outcomes of competing species w/ identical niches (not just living in the same area)

2. Resource Partitioning

1. Extinction of one species2. Evolution of one species to use a

different set of resourcesResource partitioning is the differentiation of niches that enables similar species to coexist in a community.

Reproductive Potential

…Is an organism’s ability to grow at the fastest rate.

(To replenish the species—innate!)

REPRODUCTIVEPOTENTIAL COMPARISON

1. R-selectedHint: Rapid Reproa. Early

reproductionb. Short life spanc. Hi mortalityd. Little/no

parental caree. Large # of

offspring produced

2. K-selected Hint: Longer Reproa. Late

reproductionb. Long life spanc. Low mortalityd. High parental

caree. Small # of

offspring produced

REPRODUCTION TYPES

K-SELECTED TYPER-SELECTED TYPES

Reproduction Connection Which of the following is generally

true of a K-strategist species? A. They reach sexual maturity faster. B. They have more young. C. They are likely to be invasive

species. D. They have longer life spans. E. Their populations cycles are more

rapid.

The interrelatedness of interactions between species makes communities complex

The Complexity of Community Networks

Figure 19.17

WoundingDetection by plant

Release of volatile attractants

Recruitment

Chemical in saliva