Cothurnia limnoriae - NSCEP | US EPA - US Environmental ...

APPROACH AND DEFINITIONS
Marine Biogeographic Schema and Geographic Scope of the Atlas
One of our main objectives was to synthesize the global distributions of near-coastal
nonindigenous species that occur within the PICES countries. To achieve this, we used the
“Marine Ecoregions of the World” (MEOW) biogeographic schema (Spalding et al., 2007;
http://www.worldwildlife.org/science/ecoregions/marine/item1266.html) as the framework for
analyzing and displaying species’ distributions. MEOW is a hierarchical biogeographical schema
for near-coastal ecosystems to an approximate 200 meter depth, and it is increasingly being used
to evaluate regional and global patterns (e.g., Molnar et al., 2008; Piepenburg et al., 2011; Ocean
Biogeographic Information System, OBIS, http://iobis.org/mapper/).
The MEOW schema consists of 12 realms, 62 provinces, and 232 ecoregions. However, one
limitation is that it does not split the Pacific and Atlantic into east/west components. The lack of
such a split limits the ability to analyze patterns of transoceanic invasions, which account for
most near-coastal invasions in the Northern Hemisphere (see Ruiz et al., 2000). To accommodate
transoceanic invasions, the 12 realms were divided (Figure 1), adding a new level between the
realm and province levels to provide east-west breaks (Reusser and Lee, 2011). This
modification divided the MEOW North Pacific Realm into Northeast Pacific Region (NEP),
composed of nine ecoregions ranging from the Gulf of California through the Aleutian Islands
(Figures 2 and 8), and the Northwest Pacific Region (NWP) composed of eight ecoregions
ranging from the East China Sea through the Kamchatka Shelf (Figures 2 and 5). Other
modifications include the addition of Caspian Sea, Aral Sea, and Sea of Asov ecoregions, which
were combined with the Black Sea to form the Ponto-Caspian Region (Figure 17), and the
addition of a High Arctic Region (Figure 1) above the Arctic ecoregions. These modifications
result in a total of 20 regions (Figure 1).
Capturing all the non-Arctic shorelines bordering the PICES countries required adding several
ecoregions outside the North Pacific Realm. The Hawaii Ecoregion, which is in the Eastern Indo-
Pacific Realm (Figures 2 and 7), was included to complete coverage of the U.S. Pacific states.
For complete coverage of China and Japan, nonindigenous species were also reported from five
ecoregions in the Central Indo-Pacific Realm (Southern China, Gulf of Tonkin, South China Sea
Oceanic Islands, South Kuroshio, and Ogasawara Islands; Figures 2 and 6). We refer to these
five ecoregions as the North Central-Indo Pacific (NCIP) and they were analyzed as a group
even though they do not form a natural biogeographic entity. Because of the sparse information
on the ecoregions in the NCIP and the artificiality of the NCIP as a biogeographic unit, we report
the number of NIS from the NCIP but do not analyze the results in detail.
The specific objective of the project then became the synthesis of the distributions and
habitat/natural history attributes of all the reported near-coastal NIS in the 23 MEOW ecoregions
in the NEP, NWP, NCIP, and Hawaii (Figure 2). Nonindigenous species found only in the Arctic
ecoregions of PICES countries (e.g., Eastern Bering Sea, Chukchi Sea, Beaufort Sea, Siberian
Sea) were not included in PICES database or the Atlas. While the distributions of NIS were
mapped at the ecoregion scale, most of the analyses in the Atlas were conducted on the four
biogeographic units (NEP, NWP, NCIP, and Hawaii). Additionally, the PICES database is
designed around analyses at the region scale. While analyses at the ecoregion scale are possible
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