TOWARD A METABOLIC THEORY OF ECOLOGY

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SUSTAINABILITY ASSUMPTION, HYPOTHESIS,
OXYMORON?

• James H. Brown
• Department of Biology
• University of New Mexico
• Mojave Desert Science Symposium
• November 2004

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• Benchmarks
• Ecological Society of America
• 1998 Lubchenco et al. The sustainable biosphere
  initiative
• 2004 Palmer et al. Ecological science and
  sustainability for a crowded planet
• Science
• 2001 Kates et al. Sustainability science
• 2003 McMichael et al. New visions for addressing
  sustainability
• Proceedings of the National Academy of Science,
  USA
• 2003 Clark and Dickson. Sustainability science
  the emerging research paradigm
• Books
• 1997 Daily. Natures services societal
  dependence on natural ecosystems
• 2003 Hall. Quantifying sustainable development
• 2003 Millenium Ecosystem Assessment. Ecosystems
  and human well-being

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Concepts of Sustainability

• Long history in the environmental sciences
• Sustainable biosphere
• maintenance of ecological goods and
  services to
• support human population, ecosystem
  function, and
• biodiversity
• Sustainable development
• economic progress without social or
  environmental
• damage
• Sustainable agriculture
• food and fiber production for human use
• Sustained yield of natural resources
• fisheries, wildlife, timber, livestock forage

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What is meant by sustainability?

• Ecological system
• productivity
• biodiversity
• landscape
• heterogeneity
• human population
• and economy

• Equilibrial exchange
• energy
• materials
• organisms
• humans

• Input subsidies
• energy
• materials
• organisms
• humans

• Output losses
• energy, materials, organisms

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Sustainable biosphere?

• Ecological system
• 6 billion people
• modern technological
• economy
• agricultural
• productivity
• biodiversity
• ecosystem services

• Input subsidies
• fossil fuel energy

• Output losses
• heat

• Degrading transformations
• dispersion of concentrated materials
• production of toxins and pollutants

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Sustainable development?

• Ecological system
• improved standard
• of living
• modern technological
• economy
• agricultural
• productivity
• biodiversity
• ecosystem services

• Input subsidies
• fossil fuel energy
• material resources

• Output losses
• products
• pollutants

• Degrading transformations
• dispersion of concentrated materials
• production of toxins and pollutants

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Sustainable agriculture?

• Degrading transformations
• altered soil and water
• regime
• biodiversity loss

• Input subsidies
• fossil fuel energy
• fertilizers
• water
• pesticides
• human, animal, and
• machine labor

• Goals
• food and fiber
• production
• primary production
• nutrient cycling

• Output losses
• harvested products
• soil erosion
• pollutants

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Sustainable yield of natural resources?

• Ecological system
• resource
• productivity
• ecosystem function
• biodiversity

• Input subsidies
• fossil fuel energy
• human and
• machine labor

• Output losses
• natural products
• timber/fish/meat

• Degrading transformations
• diverse environmental impacts

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Assessment of Sustainability

• Sustainable biosphere with 6 billion humans?
• oxymoron
• energy subsidy from finite supply of fossil
  fuels
• Sustainable development?
• oxymoron
• inputs of energy and material subsidies
• outputs of pollutants
• Sustainable agriculture?
• hypothesis
• even with energy, material, and labor
  subsidies?
• Sustained yields of natural resources?
• hypothesis
• with minimal energy and labor subsidies?

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Example Sustainable ecology and ranching on the
borderlands

• Place
• Malpai Borderlands 2500 km2 in New Mexico and
  Arizona adjoining U.S.-Mexico Border
• Stakeholders
• Malpai Borderlands Group 20 ranching families,
  Government agencies and NGOs, scientific advisors
• Goals
• Ecologically and economically sustainable
  livestock ranching
• Preserve open space, biodiversity, ecological
  processes
• Threats
• Rural subdivision
• Overgrazing
• Endangered species

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Example sustainable livestock grazing on Malpai
Borderlands
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Rural subdivision
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Overgrazing
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Ridge-nosed rattlesnake
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Jaguar
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Chiricahua Leopard frog
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The model Ecology dictated by four primary
processes

• 1) Spatial variation in topography, geology and
  soils
• 2) Temporal variation in climate and weather
• 3) Grazing by large herbivores (now mostly
  domestic livestock)
• 4) Fire

Adaptive management tomanipulate two processes
1) Livestock grazing 2) Fire
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Spatial variation in topography, geology and
soils
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Temporal variation in climate and weather
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Megaherbivore grazing
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Fire
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Successes to date

• Initiated ecological and economic ranching
  practices
• Adoption of adaptive management practices
• Natural and prescribed burns
• Permanent vegetation monitoring plots to track
  changes
• Grass bank to prevent overgrazing during
  droughts
• Experimentation with cattle breeds and marketing
  
• Preservation of open space
• Conservation leases to prevent subdivision into
  rural ranchettes
• Alternative livelihoods biotourism, photo and
  hunting safaris
• Limited loss of biodiversity
• reintroduction/recovery of many endangered
  species (bighorn, prairie dog, bison, jaguar,
  turkey)
• aquatic and riparian ecosystems continued loss
  of native species and invasions of exotic species

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Long-term prognosis? Most uncertainties are
external

• Sustainable ranching at local to regional
  scales requires energy, material, and economic
  subsidies
• Fossil fuels to power vehicles, machinery and
  households
• Income from livestock and other commodities
• Development pressure from growing populations in
  Tucson, Sierra Vista, and surrounding areas
• Changing livestock markets, material and
  transportation costs, taxation and societal
  incentives
• External threats to biodiversity
• Reduction or loss of source populations, habitat
  and dispersal corridors in surrounding regions

Time frame for sustainability? 50 years?
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Bottom line (regional to local scale)

• Some degree of sustainability of is possible, BUT
  IT WILL REQUIRE
• Consideration of ecological and human
• factors
• Energy, material and economic subsidies
• Continual monitoring and adaptive
• management
• Protection from degrading external
• processes

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Bottom line (national to global scale)
Sustainability of human civilization with
current population and standard of living is
threatened by five horsemen of the apocalypse

• energy
• disease
• food
• water
• pollution

but energy is by far the most important
and global oil supply is being depleted
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