Invasive Species Ecological Risk Assessment

Using the relative risk model to calculate risk due to non-indigenous species

Ecological risk assessment for Invasive species is a developing field of study. Most research on the risk assessment of invasive or non-indigenous species have focused on hazard and exposure,  not on risk as currently understood or at a regional scale. At a regional scale there are always multiple other stressors, a variety of environmental gradients, spatial heterogeneity and a wide variety of valued characteristics.  These factors make estimating risk a daunting but achievable task

In order to estimate regional  risk due to invasive species at a regional scale we used spatially explicit conceptual models based upon the source-stressor-habitat-impact relative risk model as formulated by Landis and Wiegers.  This approach was integrated with the Hierarchical Patch Dynamics Paradigm (HPDP) as formulated by J. Wu and colleagues.   This type of conceptual models for invasive species were applied to Cherry Point, Washington for the European Green Crab, , to the Chesapeake Bay and the Asian Oyester and the mid-Atlantic states and the Nun Moth.  In the Cherry Point Washington area the species of interest are the European Green Crab and the algae Sargassum muticum. In the Chesapeake Bay area the Nun Moth and the Asian Oyster are the invasive species being investigated.  Although the Nun Moth is a forest species, our endpoints are at the watershed level.

These assessments are complete and include relative risks to endpoints and uncertainty analysis. In the Chesapeake Bay area the Nun Moth and the Asian Oyster are the invasive species being investigated. Although the Nun Moth is a forest species, our endpoints are at the watershed level. Our efforts to date have demonstrated that the combination of the relative risk model and the HPDP is amenable to estimating risks due to invasive species at a regional scale. The overall approach appears to be a robust framework in which to build a risk assessment dealing with a variety of biological agents at landscape and regional scales.

The EPA grant report "Development of a Conceptual Model for Non-Indigenous Species for the Mid-Atlantic States" is available as a pdf file. The 2007 Colnar and Landis paper was fortunate in being selected as the best ecological risk assessment paper published in the journal Human and Ecological Risk Assessment for 2007.

Invasive species risk assessment publications

Landis WG, Chen VC, Colnar, AM, Kaminski L., Kushima G., Seebach, A. 2010. Chapter 12: Landscape non-indigenous Species Risk Assessment: Asian Oyster and Nun Moth Case Studies.  In Kapustka, LA. and Landis WG. Environmental Risk Assessment and Management from a Landscape Perspective. John Wiley & Sons, Inc. New York pp 245-278.

Seebach, A., Colnar AM, Landis WG.  2010. Chapter 13: Ecological Risk Assessment of the Invasive Sargassum muticum for the Cherry Point Reach, Washington USA.  In Kapustka, LA. and Landis WG. Eds. . Environmental Risk Assessment and Management from a Landscape Perspective. John Wiley & Sons, Inc. New York pp 279-301.

Colnar, AM and Landis WG.2007.Conceptual model development for invasive species and a regional risk assessment case study: the European Green Crab, Carcinus maenas, at Cherry Point, Washington USA, Human and Ecological Risk Assessment. 13:120-155. Selected best Ecorisk paper for HERA 2007.

Deines,AM., Chen V, Landis WG. 2005. Modeling the risks of non-indigenous species introductions using a patch-dynamics approach incorporating contaminant effects as a disturbance. Risk Analysis 6: 1637-1651

Landis W. G 2004. Ecological risk assessment conceptual model formulation for nonindigenous species.  Risk Analysis 24:847-858