NEMESIS is being implemented, through an iterative series of phases, to provide on-line access to our expanding database for a diverse range of users -- including resource managers, scientists, students, policy-makers, industry groups, and the public.

Structure & Operation

NEMESIS organizes information on non-native species in a geographically explicit and hierarchical fashion (Figure 1). Species records are collected from a diverse array of sources --- including publications, reports, field surveys, museum collections, and public sightings (see "Report a Species" to contribute new records). The species records include geographic localities, which are combined with detailed information about the species' biology, ecology, taxonomy, and bibliography (for further description see "About the Database"). The combined information is used to produce reports and analyses on various geographic scales:

Bays are used as the primary geographic scale of synthesis, for reports and fact sheets, because most records of non-native marine species are from protected bays and estuaries. Data from bays serve as the "building blocks", contributing hierarchically to syntheses at the increasing spatial scales of biogeographic region, coast, and continent.

Species-level information is continually under collection and review, and modifications to the database are reflected instantaneously by NEMESIS, which is a dynamic system.

Figure 1. Geographical Hierarchy

Current Status

Our database currently includes species lists for most coastal bays (and subsequent hierarchical levels) throughout the continental U.S. New records are being accrued on a continuing basis, as they become available, to remain current and grow the overall information base.

We are now initiating on-line access to these data, beginning at the level of bays. At the present time, NEMESIS provides access to data on non-native species in the Chesapeake Bay. This serves as an example of the information structure and species reports, which will be made available for other bays throughout the country over the coming months.

NEMESIS should complete this process of bay-specific syntheses over the next year. Syntheses at the greater spatial scales will also become available within the same timeframe, beginning with the Northeastern U.S.

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