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Published byKerry Scott Modified over 9 years ago
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Steps 1 & 2: Defining the case & listing candidate causes for the Truckee River case study
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2 Step 1: Define the Case List Candidate Causes Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Detect or Suspect Biological Impairment As Necessary: Acquire Data and Iterate Process Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected Decision-maker and Stakeholder Involvement Stressor Identification What biological effects are observed? Where & when are they occurring? Where are comparable reference sites?
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3 Defining the biological impairment Identify subset of biological measures to focus & guide SI process Choose wisely, & where possible, aim for specificity SPECIFICITYEXAMPLESSI UTILITY coarsefailure to meet biological criteriatriggering SI process composite ↓ sensitive taxa ↓ EPT taxa listing candidate causes developing conceptual model specific ↓ Paraleptophlebia absence of brook trout grouping sites diagnosing evaluating strength of evidence
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4 Let’s start defining your case…
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5 Defining the case: what, where & when 1. What biological effects do you want to focus on? BUGS?FISH?
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6 Defining the case: what, where & when 2. Where are your impaired & reference sites?
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7 Defining the case: what, where & when Which biological variables? invertebrates fish Where does the biological variable change among your sites? Which are your impaired and reference sites? Which time scale?
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8 Defining the case: what, where & when To Do: 1.Load relevant data files Siteinfo Metrics 2.Merge files 3.Make boxplots for each biological response variable
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9 Define the Case Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Detect or Suspect Biological Impairment As Necessary: Acquire Data and Iterate Process Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected Decision-maker and Stakeholder Involvement Stressor Identification Step 2: List Candidate Causes Make a map Gather information on potential sources, stressors, and exposures Develop a conceptual model Engage stakeholders Develop “final” list
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10 Let’s start by assembling a map…
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11 Listing candidate causes Hypothesized causes of impairment – Sufficiently credible to be analyzed – Focus on proximate stressor, or stressor directly inducing effect of concern – May include sources, mechanisms of action, or several causes acting together (causal scenarios) Develop list using: – Data from site – Info on known or potential sources – Existing knowledge from site, region & elsewhere – Stakeholder input
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12 Let’s start listing your candidate causes…
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13 Listing candidate causes: initial brainstorming 1. What sources are in watershed? 2. What stressors could be causing effects?
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14 Strategies – Combine if they share causal pathways, modes of action, sources & routes of exposure, or if they interact – Re-aggregate stressors that have been unnecessarily disaggregated – Identify independently acting stressors that cause the same effect – Define effects more specifically Combining stressors Warnings – Avoid combining causes without an underlying model – Avoid broad candidate cause definitions – Don’t lose independent effects of individual causes
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15 Based on our brainstorming, let’s start developing a conceptual model…
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16 Developing a conceptual model What is it? – Diagram showing cause-effect linkages among sources, stressors, & biological effects Used for: – Initial brainstorming – Analysis framework – Communication tool SOURCE STRESSOR BIOTIC RESPONSE
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17 Using the conceptual models in CADDIS The stressor-specific diagrams are there to give you ideas, & get you thinking about what may be happening in your stream Take the parts that make sense for your system & leave the rest Pilfer & modify freely, to generate case-specific diagrams
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18 Things to keep in mind in model development Think about causal pathways — How do sources lead to stressors? — How do stressors lead to biological effects? Be as specific as possible — You do not need data for every component in your diagram — Want to identify potential data sources & types of evidence — General vs. specific impairments Be thorough & inclusive — You can always eliminate potential sources, pathways, etc. later on, but don’t limit your initial brainstorming
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19 Keeping all that in mind, let’s start drawing!
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20 The “final” list of candidate causes Fill in with final list…
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21 Now that we have a diagram, where do the data fit in?
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