Intro to Stressor Identification & CADDIS [Causal Analysis/Diagnosis Decision Information System]

1. Intro to Stressor Identification & CADDIS [Causal Analysis/Diagnosis Decision Information System] Rick Ziegler, Amina Pollard & Laurie Alexander USEPA Office of Research and Development National Center for Environmental Assessment January 5-8, 2009 / Reno, Nevada

2. What is the cause of impairment? A snapshot of Pretend Creek, a biologically impaired stream Watershed land use 5% urban, 20% agriculture % Sand & fines 30% % Canopy cover 20% NH3-N 0.9 mg/L IBI score 22

3. Topics we’ll be covering today… • Introduction to Stressor Identification (SI) & CADDIS • Quick tour of CADDIS • Steps 1 & 2: Defining the case & listing candidate causes • - Conceptual model exercise • Steps 3 & 4: Evaluating types of evidence • - Types of evidence exercise • Steps 3 & 4: Analysis & interpretation of evidence • Step 5: Identifying probable causes • - Scoring the evidence exercise • What’s next? • - Discussion & brainstorming

4. But remember – the process requires data & some time investment What does CADDIS do? • CADDIS helps you: • Identify probable causes • Communicate conclusions to others • CADDIS provides tools & information • States have used SI & CADDIS to: • Direct management action • Prioritize & get resources for data collection

5. Why Stressor Identification? • Many states & tribes use biological assessments to identify whether streams and small rivers are impaired. • In many cases, causes of impairment are unknown. • To fix the problem, you have to know what to fix.

6. CADDIS is based on a formal method SI Guidance http://www.epa.gov/caddis 2000 2005, 2007…2010

7. The goal of CADDIS • To help scientists & managers identify causes of biological impairment in aquatic ecosystems, by providing: • Methods • Information • Tools • Interpretation

8. Why use a formal method? • To provide a defensible & reproducible evaluation • To increase confidence that remedial or restoration efforts can improve biological condition • To identify causal relationships that are not immediately apparent • To prevent biases and other lapses of logic “Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself – and you are the easiest person to fool.” [Feynman 1964]

9. Let’s revisit Pretend Creek… Watershed land use 5% urban, 20% agriculture % Sand & fines 30% % Canopy cover 20% NH3-N 0.9 mg/L IBI score 22

10. Flow is always the real problem Every time I wash my car it rains This looks like the last site I studied, where DO was the problem The # 1 reason for mistaken conclusions is theory tenacity! We all make mistakes about causality • We overweight meaningful chance events • We all have biases • We all think we know how to do it • We form conclusions quickly, based on intuition & prior experiences… • …and because we’re smart, we can ably defend our opinions

11. Causation is one of the most difficult & controversial concepts in philosophy • Only one reliable method for establishing causation: randomized, replicated, controlled experiment • Unfortunately, this approach is not usually available…

12. Causation is one of the most difficult & controversial concepts in philosophy • David Hume • We experience causality as associations between events • John Stuart Mill • Manipulation of cause results in change in effect • Karl Pearson • Need to quantify association between variables • Ronald Fisher • Controlled experiments with replication and randomization • Austin Bradford Hill • Causality based on strength of evidence

13. General vs. specific causation • General – Does C cause E? • Does smoking cause lung cancer? • Does increased water temperature reduce bull trout abundance in rivers? • Specific – Did C cause E? • Did smoking cause lung cancer in Ronald Fisher? • Did increased water temperature reduce bull trout abundance in my stream?

14. Do not claim proof of causation • Use consistent process • Document evidence & inferences Our causal strategy • Identify alternative candidate causes • Logically eliminate when you can • Diagnose when you can • Use strength of evidence for remaining • Identify most likely cause

15. Detect or Suspect Biological Impairment Stressor Identification Define the Case List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected The causal analysis framework

16. Success stories

17. Fish kills • Organismal anomalies • Changes in community structure • Low biotic index values • Violation of biocriteria Detect or suspect biological impairment Stressor Identification Define the Case List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected

18. Detect or Suspect Biological Impairment • What biological effects are observed? • Where & when are they occurring? • Where are comparable reference sites? Stressor Identification Step 1: Define the Case List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected

19. Detect or Suspect Biological Impairment Stressor Identification • Make a map • Gather information on potential sources, stressors, and exposures • Develop a conceptual model • Engage stakeholders • Develop “final” list Define the Case Step 2: List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected

20. Detect or Suspect Biological Impairment Stressor Identification • EVIDENCE FROM THE CASE • Co-occurrence • Exposure or mechanism • Causal pathway • Stressor-response relationships from field • Manipulation • Lab tests of site media • Temporal sequence • Verified predictions • Symptoms Define the Case List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Step 3: Evaluate Data from the Case Evaluate Data from Elsewhere Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected

21. Detect or Suspect Biological Impairment Stressor Identification Define the Case • EVIDENCE FROM ELSEWHERE • Stressor-response relationships (from lab, other field studies, or ecosystem models) • Mechanistically plausible cause • Manipulation at other sites • Verified predictions • Analogous stressors List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case Step 4: Evaluate Data from Elsewhere Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected

22. Detect or Suspect Biological Impairment Stressor Identification Define the Case List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case • Weigh strength of evidence for each cause • eliminate if you can • diagnose if you can • Compare strength of evidence across causes Evaluate Data from Elsewhere Step 5: Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected

24. Detect or Suspect Biological Impairment Stressor Identification Define the Case List Candidate Causes Decision-maker and Stakeholder Involvement As Necessary: Acquire Data and Iterate Process Evaluate Data from the Case Evaluate Data from Elsewhere • Causal analysis is one step in management process… • After causes identified, sources & management actions must be identified • Biological monitoring verifies that actions are effective Identify Probable Cause Identify and Apportion Sources Management Action: Eliminate or Control Sources, Monitor Results Biological Condition Restored or Protected