Biomes, Landscapes, Restoration, and Management

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Biomes, Landscapes, Restoration, and Management

• Chapter 5

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Outline

• Terrestrial Biomes
• Aquatic Ecosystems
• Human Disturbance

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TERRESTRIAL BIOMES

• 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.

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15 POINT DISCUSSION QUESTION

• Discuss a TERRESTRIAL BIOME. Present ABIOTIC
  factors (climate, weather, rainfall, humidity,
  plant nutrients, and other nonliving factors)
  that have an influence over the type of plants
  and animals that live in this biome.
• Give examples of plants and animals and their
  adaptations for living in this biome.
• Discuss Humans role in the disturbance of this
  biome.

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Fig. 5.3
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Deserts

• 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.

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Fig. 5.4
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Grasslands

• 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.

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Tundra

• 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.

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Fig. 5.7
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Conifer Forests

• 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.

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Conifer Forests

• 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.

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Conifer Forests

• Temperate Rainforest
• Wettest portion of coniferous forests of Pacific
  Northwest.
• Mild temperatures, and very abundant
  precipitation. (gt250 cm)
• Canopy condensation is major form of
  precipitation.

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Broad Leaf Deciduous Forest

• 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.

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Mediterranean

• 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

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Fig. 5.9
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Tropical Moist Forests

• 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.

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Fig. 5.10
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Tropical Moist Forests

• 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.

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Tropical Seasonal Forests

• 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

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AQUATIC ECOSYSTEMS

• Saltwater ecosystems cover vastly more total area
  and contain much greater volume of water than all
  freshwater bodies combined.
• Oceans hold bulk of worlds water.
• Aquatic ecosystems are influenced by local
  characteristics of climate, soil, and resident
  communities, and also by adjacent terrestrial
  ecosystems.

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Fig. 5.12
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Critical Aquatic Characteristics

• Dissolved Substances
• Suspended Matter
• Depth
• Temperature
• Flow Rate
• Bottom Characteristics
• Internal Convective Currents
• Connectivity to Other Aquatic Ecosystems

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Vertical Component

• 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.

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Estuaries

• 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.

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Wetlands

• 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.

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Coastal

• 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.

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Barrier Islands
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HUMAN DISTURBANCE

• 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.

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Table 5.1
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LANDSCAPE ECOLOGY

• 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.

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Patchiness and Heterogeneity

• 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.

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Landscape Dynamics

• 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.

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RESTORATION ECOLOGY

• Restoration Ecology - Seeks to repair or
  reconstruct damaged ecosystems.
• Restoration - Active manipulation to re-create
  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.

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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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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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Restoration Ecology Questions

• 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 ?

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ECOSYSTEM MANAGEMENT

• 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.

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Ecosystem Management Critiques

• 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

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Summary

• Terrestrial Biomes
• Aquatic Ecosystems
• Human Disturbance
• Landscape Ecology
• Restoration Ecology
• Ecosystem Management

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