Transcript Understanding Our Environment

Biomes, Landscapes,
Restoration, and Management
Chapter 5
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Outline:
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Terrestrial Biomes
Aquatic Ecosystems
Human Disturbance
Landscape Ecology
Restoration Ecology
Ecosystem Management
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
TERRESTRIAL BIOMES
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Biomes - Areas sharing similar climate,
topographic and soil conditions, and roughly
comparable communities.
 Temperature and Precipitation are among
the most important determinants in biome
distribution.
 Most terrestrial biomes are identified by the
dominant plants of their communities.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Deserts
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Characterized by low moisture levels and
precipitation that is infrequent and
unpredictable from year to year.
Wide daily and seasonal temperature
fluctuations.
Soils are easily disturbed by human activities,
and slow to recover.
Plants exhibit water conservation
characteristics.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Grasslands
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Communities of grasses, seasonal
herbaceous flowering plants, and open
savannas.
Few trees due to inadequate rainfall.
Large daily and seasonal temperature
fluctuations.
Frequent grass fires.
Historic grazing by roaming herds of large
ungulates.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Tundra
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Treeless
Very short growing season, with cold harsh
winters.
Damage slow to heal
 Arctic Tundra exhibits low productivity,
diversity and resilience.
 Alpine Tundra receives intense solar
radiation, hot daytime summer ground
temperatures, and potential droughts.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Conifer Forests
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Cone-Bearing
Plants reduce water loss by evolving thin,
needle-like evergreen leaves with thick waxy
coating.
 Can survive harsh winters or extended
droughts and accomplish photosynthesis
even under poor conditions.
Fire often plays role in maintenance.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Conifer Forests
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Boreal Forest - Northern Conifer Forest
 Broad band of mixed coniferous and
deciduous trees between 45° and 60° N
latitude.
 Moist and cool climate with abundant
streams and wetlands.
Taiga - Northernmost edge of boreal forest
 Species-poor. Harsh climate limits
productivity and resilience.
- Produce large peat bogs.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Conifer Forests
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Temperate Rainforest
 Wettest portion of coniferous forests of
Pacific Northwest.
 Mild temperatures, and very abundant
precipitation. (>250 cm)
- Canopy condensation is major form of
precipitation.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Broad Leaf Deciduous Forest
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Temperate regions support lush summer
plant growth when water is plentiful.
 Deciduous leaves an adaptation to
freezing temperatures.
Eastern half of US was covered with broad
leaf deciduous forest when European settlers
arrived. Much of that was harvested a
century ago for timber.
 Now large areas have re-grown and are
again approaching old-growth status.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Mediterranean
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Characterized by warm, dry summers and
cool, moist winters.
Fires are a major factor in plant succession.
Referred to as Chaparral in California.
 Biodiversity hotspot
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Tropical Moist Forests
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Humid tropical regions support one of most
complex and biologically rich biomes.
Ample rainfall and uniform temperatures.
 Cloud Forests - High mountains where fog
and mist keep vegetation continually wet.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Tropical Moist Forests
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Tropical Rainforests - More than 200 cm
annual rainfall with warm-hot temperatures
year-round.
- 90% nutrients tied up in living organisms.
- Rapid decomposition and nutrient cycling.
- Thins soil cannot support continued
cropping, and cannot resist erosion.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Tropical Seasonal Forests
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Semi-evergreen and partly deciduous forests
tending toward open woodlands and grassy
savannas.
 Characterized by distinct wet and dry
seasons with hot temperatures year-round
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
AQUATIC ECOSYSTEMS
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Saltwater ecosystems cover vastly more total
area and contain much greater volume of
water than all freshwater bodies combined.
 Oceans hold bulk of world’s water.
Aquatic ecosystems are influenced by local
characteristics of climate, soil, and resident
communities, and also by adjacent terrestrial
ecosystems.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Critical Aquatic Characteristics
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Dissolved Substances
Suspended Matter
Depth
Temperature
Flow Rate
Bottom Characteristics
Internal Convective Currents
Connectivity to Other Aquatic Ecosystems
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Vertical Component
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Vertical stratification is an important aspect
of many aquatic ecosystems.
 Organisms tend to form distinctive vertical
sub-communities.
- Benthos - Bottom sub-community.
 Low oxygen levels
- Thermocline - Distinctive temperature
transition zone that separates warm
upper layer and deeper cold layer.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Estuaries
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Estuaries - Bays or semi-enclosed bodies of
brackish water that form where rivers enter
the ocean.
 Usually carry rich sediments.
- Fan-shaped sediment deposit (delta)
formed on shallow continental shelves.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Wetlands
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Land surface is saturated or covered with
water at least part of the year.
 Swamps - Wetlands with trees
 Marshes - Wetlands without trees
 Bogs and Fens - Waterlogged soils that
tend to accumulate peat.
Water usually shallow enough to allow full
sunlight penetration.
Trap and filter water, and store runoff.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Coastal
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Barrier Islands - Low, narrow, sandy islands
that form offshore from a coastline.
 Protect inland shores from surf.
 Prized for human development.
- Loss of vegetation triggers erosion.
Coral Reefs - Accumulated calcareous
skeletons of colonial organisms (coral).
 Depth limited by light penetration.
 Among most endangered communities.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Barrier Islands
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
HUMAN DISTURBANCE
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By some estimates, humans preempt about
40% of net terrestrial primary productivity.
Temperate broad-leaved deciduous forests
are the most completely human-dominated
biome. Tundra and Arctic Deserts are the
least disturbed.
About half of all original wetlands in the US
have been degraded over the past 250
years.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
LANDSCAPE ECOLOGY
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Landscape Ecology - The study of reciprocal
effects of spatial patterns on ecological
processes.
 Spatial patterns shape, and are shaped by,
ecological processes occurring in them.
 Considers humans an element of most
landscapes.
- Few places, if any, are devoid of human
impacts.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Patchiness and Heterogeneity
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Landscape ecologists claim all landscapes
consist of similar mosaics of discrete,
bounded patches with different biotic or
abiotic composition.
 Predominate cover type acts as a matrix in
which other patch types are embedded.
- Landscape heterogeneity can exist
across a wide range of scales.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Landscape Dynamics
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Boundaries between habitat patches are
considered significant.
 Dynamics between patches may be of
greater importance than processes within
each patch.
- Departs from classic ecological focus,
and aligns with conservation biology.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
RESTORATION ECOLOGY
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Restoration Ecology - Seeks to repair or
reconstruct damaged ecosystems.
 Restoration - Active manipulation to recreate species composition and ecosystem
processes as close to pre-disturbance state
as possible.
 Rehabilitation - Attempt to rebuild ecological
structure or function without necessarily
achieving original conditions.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Restoration Ecology
Remediation - Cleaning chemical
contaminants from a polluted area by
physical or biological methods.
- Living organisms are highly effective
cleaning agents for many contaminants.
 Reclamation - Chemical or physical
manipulations of severely degraded sites.
- Historically - irrigation projects to
transform wetlands and deserts into
agricultural production.
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Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Restoration Ecology
Re-creation - Attempts to construct new
biological communities on a severely
disturbed site where basically nothing is left
to restore.
 Mitigation - Developers and government
agencies are often required to mitigate
damage caused in one area by re-creating
a comparable biological community
somewhere else.
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Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Restoration Ecology Questions:
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Is the best strategy to avoid destruction in the
first place, or is nature a simple social
creation to be molded ?
Under what conditions can / should we walk
away let nature heal itself ?
What role should community / plant
authenticity place in restoration ?
 Which historic state should an area be
restored to ?
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
ECOSYSTEM MANAGEMENT
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Ecosystem Management - Attempts to
integrate ecological, economic, and social
goals in a unified systems approach.
Most resource agencies (Federal and state)
are attempting to identify endangered
landscapes and implement ecosystem
management as their guiding policy.
 Turning away from commodity production
and commercial / recreational resource
use as top priority.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Ecosystem Management Critiques
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We do not understand ecosystems in the
detail necessary to manage them as single
entities.
In developing countries, immediate needs of
the poor will hamper enforcement of
environmental protection.
Preservation / Management
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Summary:
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Terrestrial Biomes
Aquatic Ecosystems
Human Disturbance
Landscape Ecology
Restoration Ecology
Ecosystem Management
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.