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Final thoughts on the role of biota in global environmental change. Are species drivers or passengers?. They can be both… most are passengers a few are drivers…. the drivers have characteristics capable of altering the biogeochemistry
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Final thoughts on the role of biota in global environmental change. Are species drivers or passengers?
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)
Species as passengers: let the physical drivers change the system: Simple model of directional change
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….
Climate atmospheric chemistry fragmentation disturbance history biotic additions Talus Alpine Subalpine Montane Savanna Grassland Grassland Different ecosystems are experiencing different kinds and different intensities of stressors (replace word “stressors” with “drivers outside of their HRV”)
Ecosystem Global change issue Type climate N deposition fragmentation HRV biota Alpine Subalpine forest Montane forest Ponderosa savanna Prairie
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!!!???)
Converting science to management The science of information transfer
Relationship between science and management MANAGEMENT DECISIONS Observational errors Incorrect interpretation Theoretical misunderstanding Computer models Unrealistic assumptions Oversimplified models CONTROVERSY Crude diagnostic tools Further refinement of unimportant details CONFUSION Further misunderstanding Coincidental agreement between theory and observations Sparse and infrequent observations PUBLICATION
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?
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.
“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
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.
Introductions, extinctions Abiotic drivers B Historical Range of variability Biotic composition A Historical Range of Variability Physical Conditions
A Altered only by species changes Altered Historical C Biotic composition Altered only by Physical/chemical A B Historical Altered Environmental Conditions
New species change biogeochemical parameters B Adventive ecosystem C Altered Historical New biogeochem- ical parameters Change biotic Composition. B Historical Altered Environmental Conditions
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.”
THE ADVENTIVE ECOSYSTEM ------- ------ Role of non-native species biota
Changing climate and changing atmospheric chemistry Natural System Rock Alpine Subalpine Montane Savanna Grasslands Adventive System Rock Alpine Subalpine+homes Montane+ranchettes+homes+ Savanna +ranchettes+homes+ Grasslands+agriculture + ranchettes+suburban+urban Change in disturbance Regimes (esp fire)
One axiom of ecosystem management: “expect surprises” (the interactions that form the basic behavior of adventive ecosystems are being developed as we speak…)
State of System Vested Interests Perception Knowledge Policy and Mgmt.
State of System Vested Interests Perception Knowledge Policy and Mgmt.