1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

SECTION 2: PROBLEM FORMULATION
Representative ecological receptors were selected from these communities to fulfill as many
of the following criteria as possible:
• Species that are known to occur or are likely to occur at the site.
• Species that relate to the assessment endpoints selected.
• Species that are likely to be maximally exposed to the COPECs.
• Sedentary species or species with a small home range.
• Species with high reproductive rates.
• Species that are known to play an integral role in the ecological community structure at
the site.
• Species that are known or likely to be especially sensitive to the COPECs, and thus are
an indication of ecological change.
• Species that are susceptible to bioaccumulation/biomagnification of COPECs from a
limited number of food items.
• Species that are representative of the foraging guild or serve as food items for higher
trophic levels.
The representative species selected for the Bolsa Chica Lowlands ERA are:
• Aquatic and semi-aquatic representative species
− Plants — aquatic grasses and forbs
− Invertebrates — benthic macroinvertebrates
− Fish — mosquitofish, topsmelt, killifish, tilapia
− Birds (semi-aquatic) — black-crowned night-heron, black-necked stilt, and least tern
• Terrestrial/upland representative species
− Plants — terrestrial grasses and forbs
− Invertebrates — insects and spiders
− Birds (upland) — American kestrel and Belding's savannah sparrow
− Mammals — western harvest mouse and coyote
Plants were selected because of their importance as habitat or forage for primary consumers.
Invertebrates were selected because of their importance as prey species for secondary
consumers. Representative vertebrate species (fish, birds, and mammals) were selected
based on their occurrence or potential occurrence onsite. Bird species selected were further
restricted to those species known to feed onsite or those observed onsite. The primary
criteria used to select vertebrate species include special-status listing, size of home range,
representativeness of trophic level or feeding guild, and potential exposure to COPECs. The
selection criteria for the representative ecological receptors are provided in Table 2-22.
Aquatic Plants – Aquatic plants (e.g., grasses and forbs) are in direct contact with
potentially contaminated sediments and surface waters. They are non-mobile and would
have high exposure to COPECs. Aquatic plants may also bioaccumulate chemicals and serve
as a direct or indirect food source for fish and semi-aquatic birds.
SAC/143368(002.DOC) 2-15 ERA REPORT
7/31/02