APPENDIX 1. Recommendations from invasion biologists
TED GROSHOLZ, University of California, Davis
(The letters A-E reference different monitoring suggestions described under the first question; these same monitoring regimes are discussed under the subsequent questions).
- Briefly describe an ideal national monitoring program to be carried out at the NERRs for answering a prominent (unanswered) question in the field of invasion biology.
- A one-time census (not monitoring) of invasive species in NERR sites and in paired, unmanaged estuarine sites. Questions: Do Estuarine Protected Areas (EPAs) such as NERRs have fewer invasive species than similar unmanaged areas? Is there a positive or a negative association between the number of native species and the number of invasive species? Is there a relationship between the number of invaders and the proximity of that NERR to a major port, aquaculture facility, or other invasion source?
- Annual site-wide monitoring of invasive species in each NERR. Questions: What are the rates of new invasions for individual NERR? What is the aggregate rate of new invasions across the US? What is the rate of spread of invaders among NERR sites?
- Annual monitoring of invasive species with parallel monitoring of water quality. Questions: What is the relationship between nutrient loading and the number of invaders across all NERRs? What is the relationship between nutrient loading and the abundance of targeted invaders within a NERR?
- One time collection (distinct from census), with annual follow-up for new records, of all invasive species for genetic analysis and museum archives.
- Annual monitoring of stable isotope signatures for key taxa (primary producers, primary and secondary consumers, top predators) to identify changing trophic position within food webs.
- Give an example of how the data resulting from such a monitoring program would be or would have been helpful to you in the course of one of your own scientific investigations of invasions.
- This would have allowed me the opportunity of incorporating data from EPAs and control sites with MPAs and control sites to ask whether this broad category of managed areas (MPAs and EPAs) have fewer exotic species.
- I would like to know how invaded Elkhorn Slough is relative to other NERRs. I would also like to know to what degree invaders are moving between NERRs. This would also help to quantify the risk of new invasions for a particular NERR such as Elkhorn Slough.
- I am interested to know what human impacts contribute to invasions. I would also like to know to what degree fluctuations in estuarine food webs might are driven by nutrient availability.
- This would help with certainty of species identity, which is a constant problem for invasive species research.
- This would provide information regarding the changing trophic positions and nutrient sources for invading species
- Would the type of monitoring program you propose also be useful to coastal managers (e.g., for designing prevention or control strategies) or would it be of more basic scientific interest?
- -E. Each of these monitoring regimes would be useful to coastal managers as well as being of basic scientific interest.
- If applicable, illustrate (with a hypothetical or retrospective example) how data from your ideal monitoring program would be or would have been useful to coastal managers.
- It would be very useful to help coastal managers prioritize NERR sites in need of additional resources for invasive species management. It would also help with prioritizing areas adjacent to the NERR sites for future inclusion within an existing NERR.
- This program would allow the prioritization of NERR sites with respect to their risk of future invasion and help with distributing resources and initiating programs aimed at preventing new invasions.
- This would permit assessing a pervasive human impact that is known to alter the abundance of exotic species, and that can be reduced under certain management practices.
- This would help distinguish new invasions from older invasions, help to identify the source of some invaders, and provide references for management activities.
- This would permit allow managers to determine whether prey choices have been altered (potentially leading to declining fish and shorebird populations) after a new predator invaders a NERR.
