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Published byPosy Owens Modified over 9 years ago
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Final thoughts on the role of biota in global environmental change. Are species drivers or passengers?
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They can be both… most are passengers a few are drivers…. the drivers have characteristics capable of altering the biogeochemistry of the system (and therefore move the system outside the HRV)
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Species as passengers: let the physical drivers change the system: Simple model of directional change
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Other nominees of ecosystem transformers African C4 grasses in Chihauhuan desert (grasslandification, like cheatgrass) C4 grasses and N-fixers in Hawai’I Eastern red cedars in plain states Zebra mussels, New Zealand mud snails….
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Talus Alpine Subalpine Montane Savanna Grassland Climate atmospheric chemistry fragmentation disturbance history biotic additions Different ecosystems are experiencing different kinds and different intensities of stressors Grassland (replace word “stressors” with “drivers outside of their HRV”)
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Ecosystem Global change issue Type climate N deposition fragmentation HRV biota Alpine Subalpine forest Montane forest Ponderosa savanna Prairie
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Ecosystem Global change issue Type climate N deposition fragmentation HRV biota Alpine X X Subalpine X X forest Montane X X x ? forest Ponderosa X X X X savanna Prairie X X X X X (grasslands are therefore the most endangered ecosystem in Colorado!!!???)
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Converting science to management The science of information transfer
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Sparse and infrequent observations PUBLICATION Observational errors Incorrect interpretation Theoretical misunderstanding Oversimplified models CONTROVERSY Further refinement of unimportant details Computer models Unrealistic assumptions Crude diagnostic tools CONFUSION Further misunderstanding Coincidental agreement between theory and observations MANAGEMENT DECISIONS Relationship between science and management
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You’re fresh out of CU with a degree in environmental biology, and you’re hired to manage Boulder Open Space. What’s the first thing you do?
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You’re fresh out of CU with a degree in environmental biology, and you’re hired to manage Boulder Open Space. What’s the first thing you do? a) go drinking b) hire lawyer c) set some goals: things you want, things you don’t want. d) all of the above.
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“Ecosystem management is management driven by explicit goals… made adaptable by monitoring and research based on our best understanding of the ecological interactions and processes necessary to sustain ecosystem composition, structure, and function.” Ecological Society of America, 1996
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UNNATURAL COMPONENTS OF OPEN SPACE: 1. Fire suppression and underutilization of fire has changed species abundances. 2. Flood control has prevented riparian scouring. 3. Stream channel modification, irrigation ditches, roads and trails have greatly altered hydrology. 4. Atmospheric nutrient inputs have increased. 5. Previous land abuses have left legacies. 6. A huge number of new species have been released.
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Historical Range of Variability Physical Conditions Historical Range of variability Biotic composition A B Introductions, extinctions Abiotic drivers
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Historical Altered Environmental Conditions Altered Historical Biotic composition AB C A Altered only by species changes Altered only by Physical/chemical
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Historical Altered Environmental Conditions Altered Historical B C B Adventive ecosystem New species change biogeochemical parameters New biogeochem- ical parameters Change biotic Composition.
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The adventive ecosystem (not an accepted term… you heard it here first!) “adventive” “ Not native to and not fully established in a new habitat or environment.”
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THE ADVENTIVE ECOSYSTEM biota ------- ------ Role of non-native species
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Rock Alpine Subalpine Montane Savanna Grasslands Rock Alpine Subalpine+homes Montane+ranchettes+homes+ Savanna +ranchettes+homes+ Grasslands+agriculture + ranchettes+suburban+urban Adventive System Natural System Changing climate and changing atmospheric chemistry Change in disturbance Regimes (esp fire)
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One axiom of ecosystem management: “expect surprises” (the interactions that form the basic behavior of adventive ecosystems are being developed as we speak…)
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Vested Interests Policy and Mgmt. Perception Knowledge
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Vested Interests Policy and Mgmt. Perception Knowledge
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