Pathways of Invasives & Risk Assessment

Jim Carlton, Greg Ruiz, David Andow - Programme Leaders

Many experts believe unintentional introduction through international trade to be the leading cause of harmful invasions of exotic species worldwide. Yet, except for very few countries, a strong knowledge base does not exist on the actual pathways by which invasive species are carried from place to place. Trade, tourism, and international commerce represent the glues that bind the developed and developing countries together in the need to address the global problems presented by invasive species. Identifying and, where possible, quantifying the importance of the pathways that lead to harmful invasions will present the opportunity to build global institutional capacity to address invasive species.

The overall goal of the Vectors component of GISP is to provide a detailed analysis of pathways according to four major taxonomic groups in each of three ecosystems: Terrestrial, Freshwater and Marine. The specific goals are to:

Identify Pathways

• Identify known pathways by taxonomic group and ecosystem;

• Discuss state-of-knowledge about the relative strength of pathways in space and time (including possible future pathways of concern);

• Evaluate assumptions (implicit or explicit) in the thinking about mode and importance of various pathways;

• Identify critical gaps in our knowledge about invasion pathways.

Identify & Evaluate Vector Management Strategies

• Identify management strategies now in place to reduce future invasions in the respective pathways;

• Discuss methods for evaluating effectiveness of management strategies for key pathways, including data on actual implementation (enforcement), sampling theory (e.g., percentage of vector intercepted and examined by quarantine officials), as well as merits and limitations (constraints) of management strategies;

• Identify critical gaps in our knowledge and development of effective prevention strategies;

• Highlight key opportunities and difficulties for pathway management in the context of global trade practices and policies.

The results of this analysis will be presented in a 4-day conference and published proceedings.

Activities

• Research existing information on pathways leading to harmful invasions. /interceptions information repositories.

  • National governments

  • International authorities

  • Non-governmental organizations

  • Academic and other experts

• Existing pathways

  • U.S. Congress office of technology assessment (ota)

  • Carlton's studies of international marine pathways

  • Other studies

• Quantitative assessments of pathways for possible case study countries : Chile, Czech Republic, India, Kenya, Mauritius, New Zealand, Philippines, Portugal, South Africa, United States and follow up with comparisons of case study countries.

• Provide overall assessment of current international pathways for terrestrial invasive species.

Intentional introductions for:

• Agriculture, Forestry, Soil conservation, Horticulture, Hunting, Biological control, Research, Other

Unintentional introductions through contaminants of:

• agricultural produce

• nursery stock: cut flowers

• timber

• seeds

• inorganic material

Being attached to or carried in : mail/parcel freight, shipping containers, ships, boats, trains, airplanes, trucks, passenger cars, travelers' luggage, packing materials/crates/dunnage/pallets, other routes

• Unassisted spread from neighboring country where introduced

• Escaped from cultivation or captivity, feralized discarded

• Other sources

• Human disease vectors in relation to pathways of terrestrial invasive species

• Human disease vectors in relation to pathways of terrestrial invasive species.

• Assessment of current international pathways for aquatic (marine and freshwater) invasive species.

  • Vessels - outside and inside

  • Aquaculture, other fisheries and aquarium industries

  • Other commercial, government and private activities

  • Intentional introductions

  • Unintentional introductions

  • Scientific research

  • Canals

  • Unassisted spread from neighboring country where introduced

• Human disease vectors in relation to pathways of aquatic invasive species

• Forecasting the changing pathways of harmful introductions: Socio-economic and political trends affecting future pathways.

  • Population growth, Economic development, Political change, Consumption trends, Travel/tourism trends.

  • Impact of international trade agreements, other sources

• Technological factors affecting future pathways.

  • Transportation technologies

  • Fumigation and treatment technologies

• Projected future international pathways of greatest concern

  • Identification of particular pathways

  • Ecological, economic, health and other risks posed

The Risk Assessment facet of the GISP initiative (D. Andow):

Although invasives are widely recognized as potentially causing environmental harm the risk assessment efforts are patchy and ad hoc. Considerable attention is focused on assessing the risks of transgenic organisms to be released in the environment, historically little attention was paid to introductions of biological control organisms in the European colonies and North America. Concern about inadvertent introductions has grown to spawn the quarantine services of many countries, but considerable amounts of plant tissue still travels with relatively few fetters. There is a need to compare approaches to risk analysis of invasives to determine the necessity for creating a coherent framework for invasives and for expanding current biosafety protocols to cover invasives. Scientific risk assessment has suffered recently with the growing understanding of the social dimensions of risk analysis. Consequently, an integration of scientific and social analyses is essential for a successful comparison.

The primary approach will be to compare risk analyses for inadvertent introductions, purposeful introductions. This section will (1) compare how identified environmental risks are valued, determining if there are any normative valuation problems; characterize comparative uncertainties in risk estimation; and describe the distribution of identified and uncertain scientific risk across participants, space, and time; (2) overlay a social description of risk, focusing on several dimensions, including the voluntary/ involuntary, and deliberate/ inadvertent continua; (3) develop alternatives to and evaluate the adequacy of absolute risk analysis frameworks, and (4) evaluate need to expand current biosafety protocols to include invasives.

Activities

Compare how identified environmental risks are valued, determining if there are any normative valuation problems; characterize comparative uncertainties in risk estimation; and describe the distribution of identified and uncertain scientific risk across participants, space, and time.

Overlay a social description of risk, focusing on several dimensions, including the voluntary/involuntary, and deliberate/inadvertent continua.

• Most environmental scientists are unfamiliar with the controversies involved in valuation and distribution of risk. In addition, although most scientists have a comfortable understanding of uncertainty, few recognize how uncertainty affects risk analysis. How are risks valued? Is there a coherent valuation system by which to value environmental risks of invasives? Is the market the final arbiter of risk or some other measure of social value? To whom, where and when to benefits accrue and who bears the risks where and when? If a risk is uncertain, why does it apparently get undervalued sometimes and overemphasized others? How does the cost of valuation affect the measure and uncertainty of the risk?

• It is widely appreciated that people are willing to bear larger voluntary risks than imposed risks, and that deliberately imposed risks are less tolerated than inadvertently imposed risks. To conduct a comparative risk analysis it will be essential to understand the valuation systems that underlie these distinctions and to devise methods that are appropriate to enable comparison across these categories.

• Develop alternatives to and evaluate the adequacy of absolute risk analysis frameworks.

• Compare how identified environmental risks are valued, determining if there are any normative valuation problems; characterize comparative uncertainties in risk estimation; and describe the distribution of identified and uncertain scientific risk across participants, space, and time.

• Overlay a social description of risk, focusing on several dimensions, including the voluntary/involuntary, and deliberate/inadvertent continua.

• Develop alternatives to and evaluate the adequacy of absolute risk analysis frameworks.

Contribution to Global Strategy Document :

Goals of the Chapter. The Pathways chapter will: 1) identify the international pathways leading to invasions of harmful terrestrial and aquatic (marine and freshwater) exotic species; 2) quantitatively assess international pathways of harmful invasives since 1980, with a focus on diverse case study nations employing the assistance of in-country experts; 3) engage a variety of trade specialists, including industry and governmental experts, to forecast likely future changes in international pathways of harmful invasives in order to assist in proactive prevention of future invasions; and 4) discuss policy and related implications of the findings.

Scope of the Chapter. Within scope: international pathways of harmful terrestrial and aquatic invasions detected since 1980. Outside scope: intra-national pathways; harmful invasions detected prior to 1980 (although earlier invasions may be addressed when they supply useful comparative examples).

Draft Conclusions

• Policy implications of findings and projections

• Information/education needs regarding pathways

• Further assessment needs

• Proposed methods to evaluate projections

Outcomes:

• Current pathways reports for the case study countries assessed.

• Workshop report on forecasting future international pathways (workshop to be held November 8-11, 1999-Smithsonian Environmental Research Center, Edgewater, MD).

• Final synthesized chapter for Invasive Species Global Strategy Document.

• Various related information/education materials.

• An edited volume on valuation and distribution of scientific environmental risks associated with invasives

• An edited volume comparing risks of various invasives

Beneficiaries

Policymakers, trade regulation officials, agricultural officials, health officials, quarantine officers, industry/trade/commerce and other personnel and institutions concerned with invasive species, scientific community, conservation community, educational community, geographers.

• Visit the Smithsonian Environmental Research Center (SERC)