Title: Sustaining Terrestrial Biodiversity: The Ecosystem Approach
1Sustaining Terrestrial Biodiversity The
Ecosystem Approach
210-1 What Are the Major Threats to Forest
Ecosystems?
- Concept 10-1A Forest ecosystems provide
ecological services far greater in value than the
value of raw materials obtained from forests. - Concept 10-1B Unsustainable cutting and burning
of forests, along with diseases and insects, are
the chief threats to forest ecosystems. - Concept 10-1C Tropical deforestation is a
potentially catastrophic problem because of the
vital ecological services at risk, the high rate
of tropical deforestation, and its growing
contribution to global warming.
3Forests Vary in Their Make-up, Age, and Origins
- Old-growth forest Original forests that have not
been disturbed for logging, road building, or
development - Sometimes called primary, ancient, virgin, or
primeval forests - 36 of worlds forest
- High biodiversity because of many specialized
niches
4Forests Vary in Their Make-up, Age, and Origins
Remaining Old-Growth Forests in the U.S.
5Forests Vary in Their Make-up, Age, and Origins
- Second-growth forest
- Area which has re-grown after a major disturbance
such as fire, insect, or timber harvest - 60 of worlds forest
- The area is reclaimed by the natural process of
secondary succession - Small shrubs and trees followed by the larger
trees
6Forests Vary in Their Make-up, Age, and Origins
- Tree plantation (tree farm)
- Planted stands of a particular tree species that
are maintained, harvested, and replanted - Typically used for paper or particle board
7Forests Provide Important Economic and
Ecological Services
Estimated annual value Economic
services 1.8 trillion Ecological services 4.7
trillion
8Unsustainable Logging is a Major Threat to
Forest Ecosystems
- Building roads into previously inaccessible
forests paves the way for increased erosion,
habitat fragmentation, loss of biodiversity, and
invasion by non-native species. - For this reason, many federal wilderness areas do
not allow the construction of roads.
9Unsustainable Logging is a Major Threat to
Forest Ecosystems
- Three major tree harvesting methods
- Selective cutting
- Clear-cutting
- Strip cutting
10Unsustainable Logging is a Major Threat to
Forest Ecosystems
- Selective Cutting
- Mature trees are harvested individually from
diverse forests - Younger trees left to harvest later
- Reduces crowding
- Removes diseased trees
- Encourages growth of younger trees
11Unsustainable Logging is a Major Threat to
Forest Ecosystems
- Clear-cutting
- Removing all trees in a single pass.
12Unsustainable Logging is a Major Threat to
Forest Ecosystems
Clear-cutting
13Unsustainable Logging is a Major Threat to
Forest Ecosystems
- Strip-cutting
- A type of clear cutting that involves clear
trees along the contours of the land. - Less erosion
14Fire, Insects, and Climate Change Can Threaten
Forest Ecosystems
- Forest fires can either benefit or harm forests
- Burn away flammable ground material
- Prevent larger, more destructive fires
- Release valuable mineral nutrients
- Stimulate new forest growth
15Fire, Insects, and Climate Change Can Threaten
Forest Ecosystems
- Surface fires
- Usually burn leaf litter and undergrowth
- May provide food in the form of vegetation that
sprouts after fire - Crown fires
- Extremely hot, burns whole trees, jump from
treetop to treetop - Fierce and hard to control
16Fire, Insects, and Climate Change Can Threaten
Forest Ecosystems
- Accidental or deliberate introduction of foreign
diseases and insects are also a major threat to
forests.
17We Have Cut Down Almost Half of the Worlds
Forests
- Human activities have reduced the earths forest
cover by as much as half. - Deforestation temporary or permanent removal of
large areas of forests - Results from unsustainable cutting of trees
- Losses are concentrated in developing countries.
- Use it for fuel heating and/or cooking
- Tropical forests
- Especially in Latin America, Indonesia, and
Africa - Boreal forests
- Especially in Alaska, Canada, Scandinavia, and
Russia
18We Have Cut Down Almost Half of the Worlds
Forests
19Tropical Forests Are Disappearing Rapidly
- Large areas of ecologically and economically
important tropical forests are being cleared and
degraded at a rapid rate.
20Tropical Forests Are Disappearing Rapidly
21Tropical Forests Are Disappearing Rapidly
- Large areas of tropical forest are burned to make
way for cattle ranches and crops. - Soil in the rainforest is very poor
- Farmers burn the trees down to provide nutrients
for the soil - Heavy rain leaches away the nutrients so they
move to another area and burn again
22Tropical Forests Are Disappearing Rapidly
- At least half of the worlds terrestrial plants
and animals live in tropical rain forests. - About 2,100 of the 3,000 plants identified by the
National Cancer Institute as sources of
cancer-fighting chemicals come from tropical rain
forests.
23Tropical Forests Are Disappearing Rapidly
2410-2 How Should We Manage and Sustain Forests?
- Concept 10-2 We can sustain forests by
emphasizing the economic value of their
ecological services, protecting old-growth
forests, harvesting trees no faster than they are
replenished, and using sustainable substitute
resources.
2510-2 How Should We Manage and Sustain Forests?
- We can use forests more sustainably by
emphasizing - Economic value of ecological services
- Harvesting trees no faster than they are
replenished - Protecting old-growth and vulnerable areas
26We Can Improve the Management of Forest Fires
- Fire prevention programs have been very
effectivetoo effective. - Large amounts of highly flammable underbrush have
accumulated - Leads to larger, more destructive crown fires
- To reduce fire damage
- Set controlled surface fires (Prescribed Fires).
- Allow fires to burn on public lands if they dont
threaten life and property. - Clear small areas around property subject to fire.
2710-3 How Should We Manage and Sustain Grasslands?
- Concept 10-3 We can sustain the productivity of
grasslands by controlling the number and
distribution of grazing livestock and restoring
degraded grasslands.
2810-3 How Should We Manage and Sustain Grasslands?
- Important ecological services of grasslands
- Soil formation
- Erosion control
- Nutrient cycling
- Storage of atmospheric carbon dioxide in biomass
- Maintenance of diversity
2910-3 How Should We Manage and Sustain Grasslands?
- Almost half of the worlds livestock graze on
natural grasslands (Rangelands) and managed
grasslands (Pastures).
- We can sustain rangeland productivity by
controlling the number and distribution of
livestock and by restoring degraded rangeland.
30Some Rangelands Are Overgrazed
- Overgrazing occurs when too many animals graze
for too long and exceed carrying capacity of a
grassland area. - Grass/shrubs are damaged beyond repair
- Reduces grass cover
- Leads to erosion of soil by water and wind
-
31Some Rangelands Are Overgrazed
- Desertification - The degradation of land that
results in a desert - Caused by overgrazing, deforestation, or overuse
- The worlds deserts are getting bigger
- Prevention of overgrazing
- Rotational grazing
- Replant barren areas
- Apply fertilizer
- Reduce soil erosion
3210-4 How Should We Manage and Sustain Parks and
Natural Reserves?
- Concept 10-4 Sustaining biodiversity will
require protecting much more of the earths
remaining undisturbed land area as parks and
nature reserves.
3310-4 How Should We Manage and Sustain Parks and
Natural Reserves?
Important Definitions
- Conservation
- Focuses on the proper use of nature
- Seeks to regulate the human use of wilderness and
its resources - Preservation
- Focuses on the protection of nature from use
- Seeks to eliminate the human use of wilderness
and its resources
3410-4 How Should We Manage and Sustain Parks and
Natural Reserves?
- National park a reserve of land, usually, but
not always declared and owned by a national
government, protected from most human development
and pollution. - Countries have established more than 1,100
national parks, but most are threatened by human
activities.
- Local people invade park for wood, cropland, and
other natural resources. - Loggers, miners, and wildlife poachers also
deplete natural resources. - Many are too small to sustain large-animal
species. - Many suffer from invasive species.
3510-4 How Should We Manage and Sustain Parks and
Natural Reserves?
- 58 Major national parks in the U.S.
- Overused due to popularity litter, trampling,
off road vehicles, etc. - Many species are isolated and fragmented from
the ecosystems around them - Air pollution from areas outside of park
3610-4 How Should We Manage and Sustain Parks and
Natural Reserves?
- Nature Reserves (Nature Preserves)
- Protected areas of importance for wildlife,
geological features, or other special interests,
which are reserved and managed for conservation. - Nature reserves may be designated by government
institutions, by private landowners, or by
charities and research institutions. - Currently 12 of earths land area is protected.
- Only 5 is strictly protected from harmful human
activities - Conservation biologists call for full protection
of at least 20 of earths land area
3710-4 How Should We Manage and Sustain Parks and
Natural Reserves?
- Wilderness is land legally set aside in a large
enough area to prevent or minimize harm from
human activities. - Only a small percentage of the land area of the
United States has been protected as wilderness.
- Wilderness Act of 1964
- Established 9.1 million acres of federally
protected wilderness in national forests
3810-5 What is the Ecosystem Approach to
Sustaining Biodiversity?
- Concept 10-5A We can help sustain biodiversity
by identifying severely threatened areas and
protecting those with high plant diversity and
those where ecosystem services are being
impaired. - Concept 10-5B Sustaining biodiversity will
require a global effort to rehabilitate and
restore damaged ecosystems. - Concept 10-5C Humans dominate most of the
earths land, and preserving biodiversity will
require sharing as much of it as possible with
other species.
3910-5 What is the Ecosystem Approach to
Sustaining Biodiversity?
- We can prevent or slow down losses of
biodiversity by concentrating efforts on
protecting global biodiversity hot spots where
significant biodiversity is under immediate
threat.
4010-5 What is the Ecosystem Approach to
Sustaining Biodiversity?
4110-5 What is the Ecosystem Approach to
Sustaining Biodiversity?