1. Sustaining Biodiversity
Ms. Sieb
1/10/2017

2. Examples of human impact
We have “disturbed” 83% of the earth’s land. Most of the damage is from filling in wetlands and converting grasslands & forests into crop fields and urban areas.
82% of temperate deciduous forests have been cleared, fragmented, & dominated
95% of virgin forests in US have been logged for agriculture, housing, & industry
¾ of the world’s commercial fish species have been overfished/hit their sustainable yield
Extinction rate has increase at least 100 times since human existence

3. Why should we care? Earth’s diversity has two types of value:
Intrinsic value: value of an organism, species ecosystem or the earth’s biodiversity based on its existence, regardless if it is useful to humans
Instrumental value: value of an organism, species, ecosystem, or the earth’s biodiversity based on its usefulness to humans

4. US Land
1/3 of the land in the US consists of publicly owned national forests, resource lands, parks, wildlife refuges, and protected wilderness areas.
National Forest Service – 155 forests & 22 grasslands used for logging, mining, farming, recreation, etc.
National Resource Land – used for mining, oil & gas extraction, & livestock grazing
US Fish & Wildlife Service – protect habitats & breeding grounds and protect endangered species
National Parks System – camping, hiking, sport fishing, and boating
National Wilderness Preservation System – protects wilderness areas designated for preservation in natural condition

5. 3 types of forests
Old growth forests – uncut or regenerated forests that hasn’t been disturbed in several generations
Second growth forests – results from secondary succession developing from human actions or naturally
Tree plantation (farm) – uniformly aged trees 1-2 species that are harvested together

6. Types of forest management
Even aged forests – trees are maintained at the same age and size (& harvested within 6-10 years of planting)
Uneven aged forests – many ages and sizes of trees to foster natural regeneration
The goal of uneven aging is diversity, sustainable production, & multiple uses
If 1/5 of the world’s forests were sustainability maintained, they could meet the needs of the current world population!

7. Harvesting trees
Need to build roads for access/timber removal (causes erosion, run-off, fragmentation, etc.)
Once you have a path, there are 5 major types of tree “cutting”:
Selective cutting: intermediate-aged or mature trees in an uneven aged forest are cut singly or in small groups
Shelterwood cutting: removing trees on the harvest area in a series of two or more cuttings so new seedlings can grow from the seed of older trees
Seed-tree cutting: leaves healthy, mature trees with a good cone crop in the existing stand to provide seed for regenerating a new stand of trees. Seed trees are typically removed after regeneration is established.
Clear cutting: all trees on a site are removed in a single cut
Strip cutting: clear cutting a strip of trees along the contour of the land, leaving it narrow enough to allow natural tree regeneration in a few years

8. Deforestation
Deforestation – temporary or permanent removal of large expanses of forest for agriculture and other uses.
Advantages
Disadvantages
Higher timber yield
Reduces biodiversity
Max. economic return in short time
Disrupts ecosystem processes
Reforest with genetically superior trees
Destroys & fragments wildlife habitat
Short time to establish new stand of tree
Leaves moderate to large opening
Needs less skill and planning
Increases soil erosion
Best way to harvest tree plantation
Increases sediment water pollution & flooding
Good for tree species needing full or moderate sunlight
Eliminates recreational value for many decades

9. Solutions to sustainable forestry
Conserve biodiversity along with water & soil resources
Grow more timber on long rotations
Rely more on selective cutting and strip cutting
No clear cutting, seed-tree, or shelterwood cutting on steeply sloped land
No fragmentation of remaining large blocks of forest
Sharply reduce road building into uncut forest areas
Leave most standing dead trees & fallen timber for habitats and nutrient recycling
Certify timber grown by sustainable methods

10. Fires
Forest fires can burn away flammable underbrush and small trees, burn large trees, and burn underground flammable materials
Three types of fires:
Surface fires: burn undergrowth and leaf litter on the forest floor (can kill seedlings & small trees)
Crown fires: very hot fires that can burn whole trees & jump treetop to treetop (usually occur in older forests with lots of ground litter accumulation)
Ground fires: go underground & burn partially decayed leaves & peat (can smoulder for days & can be hard to detect)

11. Reducing Forest Fire Damage
Smokey the Bear campaign – good but not all forest fires are bad; preventing ALL forest fires increases the likelihood of destructive crown fires by allowing accumulation of highly flammable underbrush & small trees
Prescribed fires - process of planning and applying fire to a predetermined area, under specific environmental conditions, to achieve a desired outcome. They reduce the catastrophic damage of wildfire on our lands and surrounding communities by:
Safely reducing excessive amounts of brush, shrubs and trees
Encouraging the new growth of native vegetation
Maintaining the many plant and animal species whose habitats depend on periodic fire
Healthy Forests Restoration Act – timber companies can cut down economically valuable medium/large trees in national forests in return for clearing away smaller, fire prone trees and underbrush.

12. Tropical deforestation
Tropical forests cover 6% of earth’s land
Studies indicate at least ½ of the world’s plant/animal life live in tropical forests
In 1970, deforestation affect 1% of Amazon water basin, by % had been deforested and degraded.
Ex. Brazil’s Atlantic coastal rainforest once covered 12% of Brazil, now 93% is gone = loss of biodiversity

13. Tropical Deforestation Continued
Primary causes of tropical deforestation are population growth, poverty, environmentally harmful government subsidies, debts owed to developed countries, and failure to value ecological services.
We should protect diverse/endangered areas and educate settlers/locals about sustainable agriculture and forestry
Reduce illegal cutting, poverty, and population growth
Reforest, rehabilitate degraded areas, and concentrate farming & ranching on already cleared areas

14. National Parks 58 national parks in the US
Popularity is a big problem; hours long waits, noise, congestion, eroded trails, & stress
Rangers have to spend more time on law enforcement & crowd control instead of education & conservation
Human activities such as logging, urban development, mining, etc. can threaten wildlife & recreation in national parks

15. Biological hotspots & wilderness
Biological hotspot - biogeographic region with significant levels of biodiversity that is under threat from humans.
Wilderness consists of areas “of undeveloped land affected primarily by the forces of nature, where man is a visitor who does not remain” (land legally set aside in a large enough area [at least 4000 sq. kilometers] to prevent or minimize harm from human activities.

16. Rehab & restoration of damaged ecosystem
Restoration: Trying to return a particular degraded habitat or ecosystem to a condition as similar as possible to its natural state
Real life example: a degraded tropical dry forest in Costa Rica is being restored in a cooperative project between tropical ecologists and local people. It was burned, degraded, and fragmented into a cattle ranch. Today, it is being restored and relinked into the rainforest it once was a part of.
Rehabilitation: attempts to turn a degraded ecosystem to a condition back into a functional or useful ecosystem without trying to restore it to its original condition
Replacement: replacing a degraded ecosystem with another type of ecosystem. Ex. a productive pasture or tree farm may replace a degraded forest.
Creating artificial ecosystems: creating an artificial wetland

17. Aquatic diversity
Water covers 71% of earth, but we’ve only explored about 5% of the global ocean
The greatest marine biodiversity occurs in coral reefs, estuaries, and the deep sea floor
Biodiversity is higher near coasts b/c of greater variety of producers, habitats, & nurseries
Biodiversity is higher near the bottom of the ocean vs. the surface due to more habitats & food sources
We should care about aquatic areas b/c it helps keep us alive & supports our economies

18. Human impact on aquatic biodiversity
Greatest threat to biodiversity of oceans is loss/degradation of habitats
Many sea bottom habitats harmed/destroyed by dredging and trawler boat (dragging weighted nets)
¾ of 200 commercially valuable marine fish overfished or fished to sustainable yield
Overfishing reduces breeding stock & unravels food webs
Coastal development, citizen unawareness, & lack of legal jurisdiction hinder protection of biodiversity

19. Protecting/sustaining marine biodiversity
Protecting endangered species
Establishing protected sanctuaries – World Conservation Union helped establish a global system
Managing coastal development
Reducing water pollution
Preventing overfishing
Protecting endangered species
Establishing protected sanctuaries – World Conservation Union helped establish a global system
Managing coastal development
Reducing water pollution
Preventing overfishing