Habitat Degradation & Loss

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Habitat Degradation Loss
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Habitat Degradation

• Habitat degradation and loss is the most serious
  threat to the majority of endangered biodiversity
• The majority of the earths land surface (83)
  has been transformed by humans to some degree
• About 60 of earths ecosystems are considered
  degraded or unsustainable

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Habitat Degradation

• Historic, current, and projected rates of habitat
  loss by type

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Habitat Degradation

• Marine systems also heavily impacted
• E.g. gt20 coral reefs destroyed and 20 degraded
  35 of mangrove of mangroves destroyed in past 20
  yrs
• 3-6x more water behind damns or in reservoirs
  relative to water in rivers

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Habitat Degradation

• Habitat degradation is the primary cause of
  extinction and endangerment globally (fig. 3.6)

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Habitat Degradation

• What is the point of knowing those specific
  factors causing the demise of a particular
  population and/or species?

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Habitat Degradation or Loss?

• Lots of factors can initiate habitat degradation
  and/or loss
• Agriculture extraction

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Habitat Degradation or Loss?

• Lots of factors can initiate habitat degradation
  and/or loss
• Development and pollution

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Habitat Degradation or Loss?

• What is the difference between degradation and
  loss?
• Degradation generally refers to impacts that
  affect many, but not all, species and that may be
  temporary
• Habitat loss usually refers to impacts so severe
  that all, or nearly all, species are adversely
  affected and will take a relatively long time to
  recover

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Habitat Degradation or Loss?

• Reduction (although not total loss) of taxonomic
  groups

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Habitat Degradation or Loss?

• Another form of degradation is habitat
  transformation
• This is a result of one habitat being converted
  into another and fundamental processes change
  (e.g. forest in cropland)

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Patterns of Habitat Transformation

• Throughout history we have been relatively
  aggressive in our modification of our surrounding
  landscape
• These direct effects also have (had) many
  indirect effects as well
• While transformations have been around for 1000s
  of years, mechanization has greatly increased
  both rate and intensity

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Patterns of Habitat Transformation
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Patterns of Habitat Transformation

• We can use historical ecology to gain a better
  understanding of what our effects have been to
  date (read Case Study 6.1)
• New tools (e.g. satellite imagery) can monitor
  change anywhere in the world relatively easily

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Patterns of Habitat Transformation

• Forest systems
• Over the past 300 yrs about 50 of the worlds
  forest cover has been removed
• 25 countries totally deforested
• 29 countries gt90 deforested
• Between 1990 and 2000, the proportion of land
  area covered by forest ecreased form 30.4 to
  29.7
• Much?

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Patterns of Habitat Transformation

• 1M km2
• Africa alone lost 8 of forests in this single
  decade

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Patterns of Habitat Transformation

• Development is frequently the causal agent
  (directly or indirectly)

Rural Ibaraki, Japan
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Patterns of Habitat Transformation

• Tropical areas are currently being deforested at
  the highest rate (although temperate had a good
  run)
• In the Amazon, up to 75 of all rainfall results
  from evapotranspiration
• Consequently, deforestation can dramatically
  alter climate patterns can change regional
  landscapes

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Patterns of Habitat Transformation

• Damage and loss to savannas
• Grasslands, shrublands and savannas cover about
  40.5 of earths surface
• These systems are maintained in herbaceous or
  shrub veg by drought, fire, freezing or grazing
• Consequently, great for crops and livestock

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Patterns of Habitat Transformation

• Damage and loss to savannas
• Temperate grasslands have been the most heavily
  converted
• In N Am, 97 of tallgrass prairie, 60 of mixed-
  and short-grass prairie converted since the
  mid-1800s

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Patterns of Habitat Transformation

• Damage and loss to savannas
• In the middle-east, Asia and northern AF,
  desertification has resulted from poor land
  management
• Causes were a combination of climate change,
  conversion for agriculture, harvesting wood for
  fuel

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Patterns of Habitat Transformation

• Degradation of freshwater systems
• With agricultural and urban expansion, water
  systems are degraded through water diversions,
  dams, and extensive wetland losses
• Presently, only 2 of US rivers run unimpeded
  (lt1/3 worldwide)
• Water development contributes to endangerment for
  91 and 99 of US federally listed fish and
  mussels, respectively

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Patterns of Habitat Transformation

• Degradation of freshwater systems
• Efforts to increase agricultural productive have
  resulted in massive water withdrawls from lakes
  and aquifers

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Patterns of Habitat Transformation

• Aral Sea has shrunk 40 in a decade

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Patterns of Habitat Transformation

• Historical loss of wetlands

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Patterns of Habitat Transformation

• Degradation of marine ecosystems
• Almost 60 of worlds population lives within
  100km of a coast and as a result, 20 of
  ecosystems adjacent to the oceans have been
  highly modeifed
• Much harder to appreciated what our impact has
  been on marine systems at a larger scale

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Patterns of Habitat Transformation

• Degradation of marine ecosystems
• Coastal estuaries have been highly damaged and/or
  lost
• Dams and diversion have starved many estuaries
  and deltas of the nutrients and sediments that
  drive these foodwebs
• Mangroves provide nursery and breeding grounds
  for fish and invertebrates, as well as buffer
  against coastal erosion

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Patterns of Habitat Transformation

• Degradation of marine ecosystems
• Other areas suffer from too much sedimentation or
  the wrong nutrients
• E.g. seagrass beds have largely been destroyed
  through sedimentation
• E.g. nitrogen pulses can create dead zones

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Patterns of Habitat Transformation

• Causes of Habitat Degradation
• Agricultural activities, extraction and
  development are the 3 big drivers in habitat
  degradation
• Also main causes of endangerment for birds and
  amphibians
• Exotics are a growing problem

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Patterns of Habitat Transformation

• Bird sp threatened by hab degradation

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Patterns of Habitat Transformation

• Causes of Habitat Degradation (Ag)
• Agricultural expansion has been the primary cause
  of ecosystem change
• Acceleration due to mechanization
• The Green Revolution expanded the intensity
  with which crops are grown
• In 1700 265M ha to 1.2B ha in 1956
• Now grow 0.3 annually

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Patterns of Habitat Transformation

• Distribution of cultivated systems (gt30)

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Patterns of Habitat Transformation

• Causes of Habitat Degradation
• Other impacts of industrial farming include high
  irrigation, heavy pesticides, herbicides, and
  pesticides all of which negatively impact
  biodiversity

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Causes of Habitat Degradation

• Urbanization and Development
• Cities are the extreme of habitat conversion with
  3 of earths surface
• They also severely impact nearby aquatic
  environments
• Ultimately their reach extends as they cannot
  provide all the resources they require in such a
  concentrated area

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Causes of Habitat Degradation

• Urbanization and Development
• Urban expansion frequently comes from arable land
• E.g. China, 5M ha of agriculture were converted
  to urbanization from 1987-92
• Waste is high correlated with density
• Coastal degradation is also highly correlated
  with urban density
• E.g. altering hydrological flows, extraction

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Causes of Habitat Degradation

• War and Violent Conflict
• Obviously war can have long-lasting and severe
  impacts on the landscape
• E.g. Vietnam and agent orange
• Africa has had many problems and as people get
  forced to live in the bush where they need
  firewood and they eat animals or poach for others

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Causes of Habitat Degradation

• Pollution
• Pollutants are particularly pervasive and can be
  found virtually everywhere
• Direct destruction is obvious, accumulation can
  be just as problematic
• Common forms of pollution include light
  pollution, waste disposal and release of
  synthetic chemicals

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Causes of Habitat Degradation

• Light Pollution
• Extensive use of electric lights has greatly
  modified the nighttime landscape
• Frogs can be temporarily blinded
• Migrant birds can be severely disoriented
• Beachfront lighting deters seaturtles

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Causes of Habitat Degradation

• Pollution

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Causes of Habitat Degradation

• Air Pollution and Acid Rain
• More pollutants go into the air than into any
  other medium
• Major sources include transportation, fuel
  combustion (power plants and large buildings),
  solid waste disposal, industrial processes, and
  burning of forests and ag fields

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Causes of Habitat Degradation

• Air Pollution and Acid Rain
• Air pollution is negatively impacting of number
  of national forests
• GSMNP gt30 plants directly damaged
• GCNP visibility is a severe problem
• Human health
• Macro and micro (lt10µ) respiratory issues

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Causes of Habitat Degradation

• Air Pollution and Acid Rain
• Acid deposition in water and land has caused
  problems worldwide
• In eastern US and Canada, acid deposition is
  30-40x greater than 1980s
• Primary source, sulfur dioxides
• Acid rain can directly harm many species of
  plants sensitive to soil pH
• In GSMNP, stream pH 5-10x greater

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Causes of Habitat Degradation

• Solid waste and Plastics
• Improper waste disposal is particularly
  problematic for
• Plastics and other nonbiodegradable items are
  quickly piling up
• Plastics (especially bags and balloons) look like
  jellyfish or other food items
• Fishery debris kills many marine mammals (e.g.
  Australia, 1500 fur seals)

oceans
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Causes of Habitat Degradation

• Marine life and Plastic

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Causes of Habitat Degradation

• Plastics
• One of the real perils of plastic is that it is
  photodegradable breaking down into smaller and
  smaller pieces, but never disappearing
• Can result in ingestion at lower trophic levels
  and subsequent bioaccumulation

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Causes of Habitat Degradation

• Chemical Pollution
• Chemicals have provided us with many conveniences
• However, we have very little idea whtat the
  long-term impact of most chemicals to the
  environment
• There are acute (immediate) problems and chronic
  (e.g. altering development, compromise immune
  system)

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Causes of Habitat Degradation

• Chemical Pollution Nitrogen
• One chemical humans have utilized that is not
  noxious is nitrogen
• However, in an attempt to improve the
  productivity of systems, humans have dumped N all
  overhow?
• Currently, approximately 2x the amount of N into
  the system as naturally occurs (but expected to
  increase another 2-3x)

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Causes of Habitat Degradation

• Chemical Pollution Increases in Nitrogen in the
  worlds watersheds

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Causes of Habitat Degradation

• Chemical Pollution Nitrogen
• While N increases productivity, it can have
  undesired effects on ecosystem structure and
  function
• May have direct (changes patterns of
  productivity) or indirect (changing patterns of
  herbivory) effects
• In aquatic habitats, can be responsible for large
  algal booms

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Causes of Habitat Degradation

• Eutrophication
• Taking a low nutrient system to a high nutrient
  system
• Despite the initial spike in productivity,
  subsequent changes occur
• Zooplankton feed on the increased phytoplankton
• All the dead zooplankton and phytoplankton sink
  to the bottom and are decomposed

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Causes of Habitat Degradation

• Eutrophication
• Landbased agricultural fertilizers are making
  their way into marine systems
• Other areas will be impacted as these fertilizers
  grow in use
• Untreated sewage is another source for eutrophic
  conditions

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Causes of Habitat Degradation
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Approaches to Global Habitat Conservation

• There are many conservation groups that take a
  global approach to conservation issues (Nature
  Conservancy, WWF, Conservation International,
  Wildlife Conservation Society)
• Problem usually what is most threatened is the
  most expensive to protect

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Approaches to Global Habitat Conservation

• Biodiversity Hotspots
• hotspots were first proposed by Norman Myers
  based upon irreplaceability and threat (n10)
• Expanded upon by those at CI and now represent 34
  regions of exceptional endemism and habitat loss
• Each holds gt1500 endemic plants and has lost gt70
  of original habitat

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Approaches to Global Habitat Conservation

• Biodiversity Hotspots
• The majority (22 of34) are tropical forests
• Areas only consist of 15.7 of earths
  landsurface but contain gt77 of all vertebrate
  species
• Over 300,000 plants (gt1/2 endemic to a single
  area) and 42 of vertebrates restricted to these
  34 regions

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Approaches to Global Habitat Conservation
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Approaches to Global Habitat Conservation

• Biodiversity Hotspots
• One positive outcome of such a strategy has been
  to draw attention (and resources) into these
  high-profile areas

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Approaches to Global Habitat Conservation

• Global 200 ecoregions
• Another approach is the global 200 plan, which
  seeks to represent each of earths ecosystem on a
  global scale
• These targets are based upon species richness,
  endemism, taxonomic uniqueness, global rarity and
  unusual ecological or evolutionary phenomena

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Approaches to Global Habitat Conservation

• Otherwise, some areas would be left-out

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Approaches to Global Habitat Conservation

• Crisis Ecoregions
• The TNC and WWF completed their strategic
  analysis of the status of worlds ecoregions
• Generated a conservation risk index based upon
  the ration of the percent of habitat converted to
  human uses to the percent of habitat protected

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Approaches to Global Habitat Conservation

• 3 levels critical (gt50 conversion, CRIgt25)
  endangered (gt40, CRIgt10), vulnerable (gt20,
  CRIgt2)

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Approaches to Global Habitat Conservation
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Approaches to Global Habitat Conservation

• Crisis Ecoregions
• There is broad overlap between the CRI and
  hotspots, as well as Global 200

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Approaches to Global Habitat Conservation

• Wilderness Protection
• Another approach is to try and protect areas
  where the habitat is still largely intact
• CI has also prioritized wilderness areas in
  tropical regions
• This approach identifies the 10 of each biome
  that is least affected by human development

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Conservation of Habitats the How

• What we have just addressed highlights where to
  implement conservation actions, but is does not
  describe how
• There are a number of factors (social and
  economic) underlying driving landuse change
  decisions
• Consequently, how to implement a conservation
  strategy will depend upon what factors are
  momentarily driving it

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Conservation of Habitats the How

• The solution is often dependent upon spatial
  scale the effort is targeted
• For example, some focus in the policy arena to
  establish natl parks, or to fund conservation
  through the purchase of development rights or
  debt-for-nature swaps (Essay 6.4)
• E.g. U.S. govt (TNC, CI, WWF) Columbia 10M
  for 11M acres

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Conservation of Habitats the How

• In the US there are many tools by which
  conservation groups can get various landowners
  (state, federal, or private) to agree to aid
  conservation efforts (albeit for other
  reasons)more later

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Conservation of Habitats the How

• The Wildlands Project