Chapter 11 – Miller – Sustaining Terrestrial Biodiversity NOTES
Gray wolf – a keystone species – culled herds of bison, elk, etc, kept down # of coyotes, provided uneaten meat for
scavengers, increased the # of willows along the stream banks that attract beavers and decrease soil erosion.
Under the Endangered Species Act (1973) the gray wolf was listed in only 48 states. 1987 the gray wolf was reintroduced
into Yellowstone despite protests from ranchers and is re-establishing the ecosystem.
Factors Increasing Biodiversity
 Middle stages of succession
 Moderate environmental disturbance
 Small changes in environmental conditions
 Physically diverse habitat
 Evolution
Factors Decreasing Biodiversity
 Extreme environmental conditions
 Large environmental disturbances
 Intense environmental stress
 Severe shortages of key resources
 Nonnative species introduction
 Geographic isolation
Biodiversity should be preserved because…
 Intrinsic value – because they exist
 Instrumental value – because of their usefulness
o Use values – economic goods & services, ecological services, recreation, sci. information, & preservation
o Nonuse values – aesthetic, existence, bequest (for future generations)
Conservation biologists use emergency responses to slow down the rate at which we are destroying and degrading
biodiversity
Bioinformatics – the applied science of managing, analyzing, and communicating biological information
Major Types of US Public Lands
 National Forest System – (Managed by the US Forest Service) used for logging, mining, livestock grazing,
farming, oil & gas extraction, recreation, hunting, fishing, and conservation of watershed, soil, and wildlife
resources
 National Resource Lands – (Managed by the Bureau of Land Management) used for mining, oil & gas
extraction, and livestock grazing
 National Wildlife Refuges – (Managed by the US Fish and Wildlife Service) protect habitats and breeding areas
for waterfowl and big game to provide a harvestable supply for hunters and also to protect endangered species –
permitted activities in these areas are hunting, trapping, fishing, oil & gas extraction, mining, logging, grazing,
farming and some military activities
 National Park System – (Managed by the National Park Service) only camping, hiking, sport fishing, and boating
can take place in parks (but hunting, mining and oil & gas extraction are allowed in recreation areas)
 National Wilderness Preservation System – lie within the borders of the other 4 public lands and are managed
by those groups but are strictly roadless areas – only hiking, camping, sport fishing, and nonmotorized boating are
allowed.
Major Types of Forests
 Old growth – an uncut or regenerated forests that has not been seriously disturbed by human activities or natural
disasters for at least several hundred years – exhibit the most biodiversity
 Second growth – a stand of trees resulting from secondary succession after the previous trees have been removed
by human activities or natural forces
 Tree plantations (tree farm) - is a managed tract with uniformly aged trees (even-age stands) that are harvested
when they become commercially valuable and are then replanted
Even-aged Management – planting of one species of trees (even-aged stands) and then harvesting them through clearcutting or shelterwood cutting
Uneven-aged Management – maintaining a variety of tree species in a stand that is of many ages and sizes to foster
natural regeneration – any wood harvested here would be done by selective cutting of individual trees or small group
cutting
Logging roads increase soil erosion, sedimentation of streams, habitat fragmentation, biodiversity loss, introduction of
invasive species, introduce other off-road vehicle use and degradation of once wilderness area
Types of Tree Harvesting
 Selective cutting – intermediate or mature trees are harvested either singly or in small groups – it reduces
crowding, encouraging growth of younger trees, maintains uneven-aged stands, allows natural regeneration from
surrounding trees
 Shelterwood cutting – removes all mature trees in an area in 2-3 different cuttings over time
 Seed-tree cutting – harvesting of almost all trees in an area but leave a few uniformly distributed seed-producing
trees to regenerate the stand
 Clear-cutting – removes all trees in an area in one cutting
o Strip cutting – removing a strip of trees along the contour of the land, with the corridor narrow enough
to allow natural regeneration
The last 3 types allow a lot of sunlight in and are good only for shade intolerant trees – so they are best used for tree
plantations and NOT for uneven-aged stands
Deforestation causes:
 Decreased soil fertility
 Soil erosion and sedimentation of waterways
 Loss of biodiversity
 Habitat loss for migratory species
 Climate change of the area (dryer & hotter)
 Increased release of CO2 from burning and decomposition of deadwood
 Accelerates flooding
Solutions for creating Sustainable Forests
 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 deadwood for wildlife habitat and nutrient recycling
 Certify timber grown by sustainable methods
 Include ecological services of trees and forests in estimating economic value
Edge effect – the area adjacent to a forest – the edge of the forest and the edge of the grassland, wetland, cropland enable a
greater biodiversity due to the merging of two ecosystems along an ecotone. This area is hotter and drier than the interior of
the forest. They are also exposed to more invasive species. Fragmenting a large forest area creates greater edge effects but
can be deleterious to the forest’s (and forest biodiversity’s) survival.
Ways to Reduce Disease Impacts on Forests
 Ban imported timber
 Selectively remove infected timber
 Develop tree species that are genetically resistant to common tree diseases
 Control insect pests with controlled spraying of conventional pesticides and use of biological organisms
Types of Fires
 Surface – burn only the undergrowth and leaf litter – these kill seedlings and small trees – most mature trees and
wildlife escape
o Beneficial because it burns away deadfall which could produce a worse fire
o It replenishes the soil with nutrients from the ash
o Pines need it to open their serotinous cones and release the seeds to germinate
o It helps to control pathogens and insects
o It replenishes the younger vegetation that a lot of ecotone dwellers require
 Crown – burn treetops and leap from treetop to treetop – occurs in forests with no surface fires for several decades
(an excessive amount of deadwood has built up) – this kills most vegetation, wildlife, buildings and creates soil
erosion
 Ground – burn partially decayed leaves or peat below the soil’s surface
Healthy Forests Initiative – timber companies are allowed to cut down economically valuable medium-large tress in
national forests for 10 years in return for clearing away smaller, more fire-prone trees and underbrush. These are exempt
from environmental reviews or appeals currently required by law.
o Bad plan because it removes the most fire-resistant trees and encourages a lot of undergrowth that will
fuel fires
o Bad plan because removing the large trees leaves more deadwood thus creating a greater fire hazard
Advantages of Logging in US National Forests
 Helps meet the country’s timber need
 Cut areas grow back
 Keeps lumber and paper prices down
 Provides jobs in nearby communities
 Promotes economic growth in nearby
communities
Ways to reduce our wood use
 Improve efficiency of wood use
o Reduce excess packaging
o Inadequate paper recycling
o Not Reusing shipping containers
Disadvantages of Logging in US National Forests
 Provides only 4% of total timber needs
 Ample private forest land to meet timber needs
 Has little effect on timber and paper prices
 Damages nearby rivers and fisheries
(sedimentation)
 It provides less jobs than recreational efforts do
 Decreases recreational opportunities

Use of kenaf or hemp (not the illegal variety)
and other agricultural residues
o Kenaf grows faster than most weeds
thus needing less herbicides
o It replenishes the soil with much
needed nitrogen
o It takes less energy and water to break
down the fibers
Tropical Forest Plants used for Medicinal Purposes
 Rauvolfia – tranquilers, high blood pressure medicine
 Foxglove – digitalis for heart failure
 Pacific yew – combats ovarian cancer
 Cinchone – quinine for malaria treatment
 Rosy periwinkle – combats Hodgkin’s disease and lymphocytic leukemia
 Neem tree – treatment of many bacterial, viral, and fungal diseases in India, also used as insecticide as well as
a natural birth control by acting as a strong spermicide
o Ideal for reforestation – it matures in only 5-7 years in poor soil in semi-arid land
TROPICAL RAINFOREST SOIL IS VERY POOR. It can be depleted of nutrients in less than 3 years! It is NOT good
for growing crops or for grazing animals.
Reasons for the cause of Tropical Deforestation
 The poor become subsistence farmers to feed their families
 Government subsidies make the wood cheaper
 Governments give title to the land where the poor clear and colonize the land
 Easy financing of large scale projects in rainforest areas for developing countries
 Failure to value ecological services of forests
Dept-for-Nature swap – countries containing rainforests protect the forest reserves in exchange for foreign aid or debt relief
Costa Rica:
 Established reserves and parks that include about 25% of its land (with 6% of it for indigenous people)
 The parks & reserves are consolidated into 8 megareserves
 Each reserve contains a protected inner core surrounded by buffer zones (for the local peoples to use for logging,
grazing, etc so that they won’t poach on the reserve itself)
The Nature Conservancy has created the world’s largest system of private natural areas and wildlife sanctuaries in 30
countries since its inception in 1951. It uses private and corporate donations to maintain a fund for buying ecologically
important pieces of land or wetlands threatened by development or other human activities.
A large reserve usually has greater species diversity than smaller reserves.
Habitat corridors between reserves of all sizes provides :
 wildlife the migration they require with protection from human interference
 permit migration when environmental conditions in a reserve deteriorate (including global climate change)
 help preserve seasonal migrational species
 threaten species by giving invasive species access
 increase exposure of species to predators, humans, pollution, etc.
Biosphere Reserve – must be large enough to contain 3 zones (core area to be protected, buffer zone for nondestructive
research, and finally a transition zone that locals can use for sustainable forestry, grazing, fishing, recreation, etc)
Adaptive Ecosystem Management –
 Integrate ecological, economic, and social principles to help maintain and restore the sustainability and biological
diversity of reserves while supporting sustainable economies and communities
 Seek ways to get govern agencies, private conservation organizations, scientists, business interests, and private
landowners to reach a consensus on how to achieve common conservation objectives
 View all decisions and strategies as scientific and social experiments and se failures as opportunities for learning
and improvement
 Emphasize continual information gathering, monitoring, reassessment, flexibility, adaptation, and innovation in
the face of uncertainty and usually unpredictable change
Ecological Restoration Methods for Ecosystems:
 Restoration to former natural state
 Rehabilitation into a functional/useful ecosystem (mining sites, landfills, clear-cut forests)
 Remediation after extraction methods, industrial exploitation so there contains no chemical contaminants (mining,
brownfields)
 Replacement with another ecosystem (tree farm for forest)
 Create artificial ecosystems (wetland mitigation)
5 principles for Effective Ecological Restoration Projects:
 Mimic nature and natural processes – let nature do most of the work (secondary succession)
 Recreate important ecological niches that have been lost (coral reef restoration)
 Rely on pioneer species, keystone species, foundation species, and natural ecological succession
 Control or remove harmful invasive species
 Reconnect small patches to form larger ones and create corridors where existing patches are isolated
Priorities for protecting the world’s remaining ecosystems:
 Take immediate action to preserve the world’s biological hot spots (map of Fig 11.24)
 Keep intact the remaining old-growth forests
 Complete the mapping of world’s terrestrial and aquatic biodiversity
 Concentrate on protecting the world’s lakes and river systems
 Focus on putting under conservation protection more ecosystem varieties
 Make conservation profitable so there isn’t poaching by locals
 Initiate ecological restoration products worldwide