# Presentation: 032985

## Risk Assessment for Invasive Species: Introduction

- Mark R. Powell
- USDA Office of Risk Assessment and Cost Benefit Analysis,
- Washington, DC

- Society for Risk Analysis
- New Orleans, LA 2002

**Notes:**
Thank you. This symposium on risk analysis for invasive species will summarize some of the papers presented at a joint workshop of the Society for Risk Analysis and the Ecological Society of America held in October 2001 at New Mexico State University. Let me just say that ORACBA, the USDA Office of Risk Assessment and Cost Benefit Analysis, was pleased to support the workshop and to find such excellent partners in addressing this challenging problem. My presentation is intended to provide some introduction for those who may be unfamiliar with risk assessment in the context of invasive species.

## OVERVIEW

- Assessing the Magnitude of the Invasive Species Problem
- Invasive Species on the Domestic and International Agendas
- Risk Assessment for Biological Stressors
- State of the Practice and Raising the Bar
- Challenges Ahead

**Notes:**
Here is a thumbnail sketch of the presentation. I’ll begin with an introduction to risk assessment, then characterize the magnitude of the problem, discuss how invasive species has been elevated onto the domestic and international policy agendas, look at the risk assessment for biological stressors and the state of invasive species risk assessment, note the events that have raised the bar for what constitutes adequate analysis, and conclude with some of the challenges ahead.

## Domestic Impacts of Invasive Species

- Major Economic Impacts
- Non-market Environmental Goods and Services
- Public Health
- Examples --

**Notes:**
As we consider the context of risk assessment for invasive species, it is worth noting that the overall magnitude of the problem is large by any measure. Although estimates vary, there is broad agreement that invasive species impose major costs on the U.S. economy. The USDA FY 2001 budget for invasive species activities alone exceeded $580 million. The scope of the problem is also broad. In addition to direct economic damages, invasive species disrupt the provision of non-market environmental goods and services, and they present risks to public health. Now, some examples of the sort of hazards that fall under the heading of invasive species...

**Notes:**
A public health example is West Nile virus (WNV), which was first positively identified in the U.S. in 1999 in a  limited area of the northeastern United States in wild birds, mosquitoes, humans, and horses. The affected area consisted of parts of Connecticut, New York, New Jersey, and one county in Maryland. 

- West Nile Virus in Wild Birds, 2002

**Notes:**
By the summer of 2002, West Nile Virus activity had spread to most eastern and mid-western states, with 113 cases and 5 deaths as of August 8. This figure presents the reported distribution of WNV in the U.S. wild bird population as of 11/20/02.

## Foot and Mouth Disease

- aphis.usda.gov

**Notes:**
Foot and Mouth Disease is a highly contagious viral infection primarily of cloven-hoofed domestic and wild animals. FMD is characterized by vesicles, with subsequent erosions in the mouth and sometimes also in the muzzle, feet, or teats. The picture on the left shows an infected water buffalo drooling. This sort of discharge is one means of viral transmission among animals. The picture on the right is of a cow with FMD lesions on the tongue. In a typical FMD outbreak scenario, sheep act as maintenance hosts, pigs amplify the virus, and cattle act as indicators, due to their susceptibility to the disease.

## UK FMD Outbreak

- www.guardian.co.uk

**Notes:**
Here are some of unpleasant scenes from last year’s outbreak of FMD in the UK.

## Citrus Canker Eradication

- Sun-Sentinel.com

**Notes:**
Here’s an example of plant pest invasion. These pictures show the ongoing program to stop the spread of citrus canker in South Florida.

## Citrus Canker Controversy

- Sun-Sentinel.com

**Notes:**
And some of the controversy surrounding an eradication program that affects residential property owners as well as commercial producers. The eradication program has been mired in litigation, and the homeowner at the right is showing a copy of the 4th Amendment to the Constitution as he refuses entry to the Florida Department of Agriculture crew.

## Salvinia molesta

- nature.org

- invasivespecies.gov

**Notes:**
Not all invasive species capture quite as much media attention or are as visually repellent. Theis close-up picture of Salvinia molesta (Giant Salivinia) on the left, for example, is quite beautiful. But as the name indicates,it’s also one of the most noxious weeds in the world. It’s a fast growing aquatic weed that, as shown on the picture at the right, can quickly clog ponds, lakes, or slow flowing streams.

## Invasive Species:  On the Domestic Policy Agenda

- National Invasive Species Council - 1999
- NISC Management Plan - 2001
- Risk Analysis System - 2003

**Notes:**
Turning to the domestic policy agenda, A number of federal agencies have invasive species jurisdiction, but the USDA Animal and Plant Health Inspection Service is a major focus. Its responsibilities include quarantine regulatory and eradication programs related to foreign animal diseases and plant pests. The APHIS quarantine inspection function was recently shifted to the new Homeland Security Department. The National Invasive Species Council (NISC) coordinates the U.S. domestic effort to manage risks associated with invasive species. The Council was established in 1999 and is co-chaired by the Secretaries of Agriculture, Interior, and Commerce. The Council’s 2001 National Management Plan calls for development of a risk analysis system for non-native species by 2003. A principal motivation for holding the ESA-SRA workshop was to contribute scientific input into the development of this system.

## Domestic Statutes Relevant to Invasive Species

**Notes:**
Scanning back over time, we see that federal law concerning non-native species has slowly accumulated since 1900. Most recently, the Plant Protection Act of 2000 and the Animal Health Protection Act of 2002 consolidated many of these statutes. Regarding Plant Protection, the 2000 Act gives the Secretary of Agriculture authority to prohibit or restrict imports, exports, or interstate movements of plant pests, plants, plant products, noxious weeds, biological control agents, and means of conveyance. That’s a broad scope. The Plant Protection Act also amends the phytosanitary regulatory decisional criteria, which some had interpreted as requiring an unattainable zero-risk policy. The Act now allows the Secretary to reduce the risk of plant pests or noxious weeds to the extent practicable and to prevent an unacceptable risk of introducing or spreading plant pests or noxious weeds. The key words here are practicable and unacceptable. These are worth emphasizing because the statutory decisional criteria dictate the risk management question. This is the question that risk analysts attempt to respond to. In turn, the question shapes the demand for data and analysis that ultimately supports regulatory decisonmaking. For example, if the statute says the criteria is “reasonable certainty of no harm,” then the research question becomes “what is the lowest level of stress at which we can detect an adverse biological response?” In contrast, the information needed to determine “what prevention is practicable” and “what risk is unacceptable” is quite different.

## Invasive Species:  On the International Agenda

- WTO SPS Agreement
- International Standard Setting Bodies: IPPC (plants), OIE (animals)

**Notes:**
Moving from the domestic to the international agenda, under the World Trade Organization Sanitary and Phytosanitary Agreement, members of the international trading community have agreed to adhere to the discipline of risk assessment to ensure that SPS measures are applied only to the extent required to protect human, animal, and plant health and do not constitute arbitrary or unjustifiable technical barriers to trade. The SPS Agreement recognizes the International Plant Protection Convention (or IPPC) and the World Organization for Animal Health (known as OIE, its French acronym) as the international standard-setting bodies for phytosanitary measures and animal health, respectively. The IPPC recently began efforts to develop plant pest risk analysis standards for environmental hazards. These standards will explicitly address risks to non-agronomic ecosystems. Plant pests are broadly defined here to include plants, animals, or pathogens directly or indirectly injurious to plants or plant products.

## Invasive Species:  On the International Agenda

- WTO SPS Agreement
- International Standard Setting Bodies: IPPC (plants), OIE (animals)
- Convention on Biological Diversity
- Cartagena Protocol

**Notes:**
Invasive species issues are also being elevated onto the international environmental agenda via the Convention on Biological Diversity. The Convention urges countries to prevent the introduction of non-native species which threaten ecosystems, habitats or species. The CBD Biosafety Protocol (also known as the Cartegena Protocol) requires decisions regarding the international movement of living modified organisms to be subject to risk assessment. Note that although the CBD entered into force in 1993, the U.S. has signed but not ratified the agreement.
Article 196 of the United Nations Convention on the Law of the Sea (UNCLOS) calls for measures to prevent, reduce and control the intentional or accidental introduction of species, alien or new, causing significant and harmful changes to the marine environment. (Note that although the Law of the Sea entered into force in1994, the U.S. has not ratified the agreement.)

## Risk Assessment for Biological Stressors

- Distinguishing Characteristics of Biological Stressors:
- Grow, reproduce, and multiply
- Disperse both actively and passively, often exhibiting “jump dispersal”
- Interact with ecosystems in complex, sometimes unpredictable, ways
- Evolve

**Notes:**
The main differences between chemical and biological stressors are that biological organisms: (a) grow, reproduce, and may multiply; (b) disperse both actively and passively, often in "jumps" that are hard to predict; (c) interact with ecosystems in ways that can be complex and are hard, if not impossible, to predict; and (d) evolve, and this evolution is largely random.

## Parallels with Chemical Risk Assessment

- Biological
- Population of invasive species in the env.
- Inactivation
- Dispersal
- Community dynamics

- Chemical
- Population of invasive cells in the body
- Sequestration
- Fate and Transport
- Chemical mixtures

**Notes:**
The distinction between risk assessment for biological stressors and chemical risk assessment may be overdrawn, however, and a number of parallels can be drawn as suggested by this slide. As a practical matter, the biggest difference may be that risk assessment for biological stressors has not adopted the sort of conventions that are generally applied as simplifying assumptions in chemical risk assessment.

## Current State of Risk Assessment of Invasive Species

- “*There are currently no known broad scientific principles or reliable procedures for identifying the invasive potential of plants, plant pests, or biological control agents in new geographic ranges*...”
- -National Research Council. 2002. Predicting Invasions of Nonindigenous Plants and Plant Pests

**Notes:**
USDA and other government agencies have been practicing risk assessment of invasive species for some year now. As suggested by this quote from a recent study by the National Academy of Sciences, however, the current state of risk assessment for invasive species is primitive. Our task is to use the best available alternatives while working toward improvement.

## Current State of Risk Assessment of Invasive Species

- Classification Schemes to Identify Hazards, Susceptible Resources
- Identifying Sources, Pathways of Hazards
- Quantitative Risk Assessment
- Risk = P(entry)
- Gap Between Entry and Consequences

**Notes:**
Traditional approaches to risk assessment of invasive species have been qualitative or categorical and focused primarily on the first component of the ecological risk assessment paradigm:  problem formulation. These efforts include developing classification schemes to predict invasiveness, identifying sources or pathways of introduction and susceptible resources and characterizing the potential biological consequences of establishment and spread. When quantitative risk assessments have been undertaken, the assessment endpoint has generally been limited to the likelihood of entry. Consequently, there is generally a gap between the risk assessment and the evaluation of potential biological and economic consequences. This typically creates demand for regulatory analysts to extrapolate beyond the available scientific data to link risk assessment endpoints to management objectives and policy goals.

## SPS Agreement Raises the Bar

- Article 5.3

**Notes:**
While most assessments are qualitative or stop at the point of entry, the SPS Agreement has raised the bar as to what qualifies as an adequate risk assessment--at least for SPS measures that might be disputed as unnecessarily trade restrictive. Article 5.3 of the SPS Agreement states that “[i]n assessing the risk to animal or plant life or health and determining the measure to be applied for achieving the appropriate level of sanitary or phytosanitary protection from such risk, Members shall take into account ... the potential damage in terms of loss of production or sales in the event of the entry, establishment or spread of a pest or disease; the costs of control or eradication in the territory of the importing Member; and the relative cost-effectiveness of alternative approaches to limiting risks.” Members are free to set their own level of protection, but the key word here is shall—that establishes an obligation to consider damages, control costs, and alternatives.

## SPS Agreement Raises the Bar

- Article 5.3
- Australian Salmon Dispute Resolution

**Notes:**
In settling a dispute over Australia’s ban on imports of fresh and frozen salmon from Canada in order to prevent entry of 24 fishborne diseases, the WTO Appellate Body established a three-pronged test for what would qualify as an adequate risk assessment under the SPS Agreement: (1) identification of the hazards and possible biological and economic consequences of their entry or spread; (2) evaluation of the likelihood of entry, establishment, or spread; and (3) evaluation of the impact of SPS measures on the likelihood of entry, establishment or spreading of the hazards. Note in particular this third element—the requirement to analyze the risk reduction potential of monitoring and surveillance, treatments, inspection, and other SPS measures that a country might require as conditions of entry.

## Argentine Citrus Decision

- U.S. Dist. Ct. E. CA. 9/01 remand of USDA regulation permitting import of Argentine citrus due to, among other things, a failure to specifically define what constitutes a “negligible risk” in this context.

**Notes:**
In a more recent domestic development, the U.S. District Court for E. CA remanded a USDA regulation permitting the import of Argentine citrus due to, among other things, a failure to specifically define what constitutes a negligible risk. Regarding the legal connotation of a negligible or de minimis risk, we need to look to the 1980 Supreme Court decision in the case of the AFL-CIO v. American Petroleum Institute, commonly known as the “Benzene” decision.

Note that Plant Protection Act does not specify any particular level of acceptable risk, negligible or otherwise.

## 1980 Supreme Court “Benzene” Decision

- “*de minimis* risk” = presumption of no additional regulation below threshold
- < 1 x 10-8 lifetime cancer risk
- “significant risk” = presumption that regulation required
- > 1 x 10-4 lifetime cancer risk
- “acceptable risk” = bounded by *de minimis* and significant risk levels, case-specific

**Notes:**
The 1980 Supreme Court decision invalidated the OSHA standard for benzene exposure on the basis that OSHA failed to consider whether existing benzene exposures posed a significant risk of harm. In its decision, the Court endorsed the concept of a "de minimis risk,” a level that was so low as to be indistinguishable from zero. Below this threshold, there would be a presumption that regulation to further reduce risk was unwarranted. The Court distinguished a “de minimis risk” from a "significant risk" for which there would be a presumption that regulation would be required. In the context of the Benzene decision, the Court found anything below a 10-8 lifetime risk of cancer to be de minimis. Anything above a 10-4 lifetime risk of cancer was found to be significant. Note that the benzene decision did not establish a bright line for what constitutes an "acceptable level” of risk. Rather it established the need for a de minimis threshold for a risk that may be regulated. The Benzene decision left a range of risk spanning four orders of magnitude within which regulatory agencies could make case-specific determinations of acceptable levels of human health risk. The distinctions among de minimis, acceptable, and significant risks may be fine, but they are nonetheless important, at least in terms of judicial review. The reason that the Benzene decision is regarded as a landmark case in the field of risk litigation is that it compelled the environmental and occupational health agencies, many of which had--and continue to have--some good arguments for advocating a qualitative approach to risk assessment, to adopt a more quantitative approach. It remains to be seen whether the Argentine citrus decision will have a similar impact on regulatory analysis for invasive species.

## ATA v EPA

- The DC District Court of Appeals 2002 decision upholding EPA's national ambient air quality standards for particulate matter and ozone.
- “Hard Look” with humility?

**Notes:**
The case law continues to evolve in the risk policy arena. After the Supreme Court overturned its prior decision, the DC District Court of Appeals recently upheld EPA’s air quality standards for particulate matter and ozone in the American Trucking Association case. While the full implications of this decision have not yet been revealed, this is potentially a major decision regarding regulatory decisionmaking under scientific uncertainty. Overall, it suggests that courts should continue to take a "hard look" at the administrative record of decision—including the risk assessment—to ensure reasoned decisionmaking. But the decision suggests that Courts need to have a great deal of humility about agencies' ability to quantify risks with much precision, especially regarding the so-called "negligible risk" level. Judicial Review – demanding version of the duty to engage in reasoned decisionmaking – blurs distinction between “arbitrary and capricious” and “substantial evidence” standard of judicial review. NEPA – courts ensure that agencies take a "hard look at environmental consequences" (Natural Resources Defense Council v. Morton, 458 F.2d 827, 838 (D.C. Cir., 1972). 

## End Result

- Scientifically ambitious risk assessment for invasive species is non-discretionary, at least for those regulatory decisions that may be disputed.

- Hazard Identification
- Entry
- Establishment
- Spread
- Risk Reduction
- Consequences

**Notes:**
In conclusion, due to international and domestic demands originating from the legal and policy realms, the practice of risk assessment for invasive species is challenged to progress beyond its traditional focus on qualitative hazard identification and to extend the quantitative analysis beyond the likelihood of entry to consider establishment, spread, the degree of risk reduction achieved by risk management measures, and the potential consequences of biological invasions. At least for measures that may be subject to dispute under the SPS agreement or via domestic litigation, scientifically ambitious risk assessment is not discretionary. There seems to be a growing recognition, however, that risk assessment can only characterize scientific uncertainty—it cannot eliminate or even reduce it. Invasive species risk management under conditions of uncertainty and multiple, competing objectives can be informed by science but is ultimately a policy judgment.

## Workshop Information

- Proceedings to be published in *Risk Analysis.*
- Papers and other materials currently available on the project website:
- http://leopold.nmsu.edu/ESA_SRA