2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
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<strong>Bolsa</strong> <strong>Chica</strong> Lowlands Restoration <strong>Monitoring</strong><br />
<strong>2008</strong> <strong>Annual</strong> <strong>Report</strong><br />
Zones 41 through 50 and Zone 66 (MTBs) occupy the northeastern section of <strong>Bolsa</strong> <strong>Chica</strong>. These<br />
zones generally contain less salt panne, with broad expanses of pickleweed. Zones 49, 50, 66, and a<br />
portion of 48 were exposed to muted tidal influence in March <strong>2008</strong>. The other zones of the MTBs were<br />
inundated by tidal overflow and rainwater for much of spring and summer, but were not open directly<br />
to the FTB. The portions of these zones closest to the residential neighborhoods have an increased<br />
amount of weedy species, particularly Zone 47.<br />
Zones 68 through 73 are located within the FTB and are subject to full tidal influence. Zone 68<br />
(Rabbit Island) is located on the western portion of the site between Inner <strong>Bolsa</strong> Bay and the FTB.<br />
This zone previously had more habitat diversity than most of the other zones, with salt marsh, alkali<br />
marsh, and upland plant species. The introduction of tidal influence in August 2006 resulted in the<br />
inundation of much of Rabbit Island during high spring tides, causing the existing low elevation<br />
habitats to die off as the area transitioned into mudflats and low to middle marsh habitats. Zone 69<br />
borders Rabbit Island to the east. Zone 71 is the newly created California least tern (Sternula<br />
antillarum browni) and western snowy plover (Charadrius alexandrinus nivosus) nesting site: Nest<br />
Site 1. Zone 71 is a relatively unvegetated, sandy strip that gently slopes towards the FTB. The<br />
remaining zones include the intertidal mudflat shelf on the eastern shore and open water bounded by<br />
riprap along the shoreline.<br />
The Muted Pocket Marsh occurs north of Rabbit Island and is not hydrologically connected to the<br />
<strong>Bolsa</strong> <strong>Chica</strong> Lowlands; rather it experiences a muted tidal influence through a restricted tidal inlet<br />
leading to Outer <strong>Bolsa</strong> Bay. This area is shallow intertidal and subtidal with salt marsh at the higher<br />
elevations. The northern shore of the Muted Pocket Marsh is lined with large eucalyptus trees that<br />
died when tidal influence was introduced. The dead trees that remain provide abundant roosting and<br />
perching habitat for multiple bird species that use the marsh.<br />
Survey Methodology<br />
Zones 1 through 66 included the MTB, Future Full Tidal Basin (FFTB), and Seasonal Ponds and were<br />
surveyed on foot by teams of field biologists. The FTB (Zones 68 through 73) was surveyed primarily<br />
by vehicles, with multiple stops to view and record birds. Much of Zone 68 was surveyed by foot<br />
along the pedestrian foot trail. Zone 71, which is a breeding colony for terns and shorebirds, and the<br />
Muted Pocket Marsh were surveyed on foot.<br />
Birding in the muted tidal basins.<br />
Surveys began in October 2007 to mark the start of Year 2 of the<br />
monitoring program and will continue every other month for a 2-year<br />
period (see Appendix 1-A for survey dates). Surveys were conducted in<br />
<strong>2008</strong> over a two-day period at each survey interval in such a way as to<br />
minimize the possibility of double-counts between the two days. The FTB<br />
and Seasonal Ponds were normally surveyed the first day, and the Muted<br />
Pocket Marsh, FFTB, and MTBs surveyed the second day. The surveys<br />
were conducted during a tide low enough to expose the mudflat on the<br />
eastern shore of the FTB, referred to often as the cordgrass bench, generally<br />
within a predicted oceanic tide range of +0.9 to +0.3m (+3 to +1 ft) NAVD.<br />
At this tide, the large sand shoals that had formed in the inlet of the FTB<br />
where large numbers of gulls, cormorants, and pelicans loaf in the<br />
afternoon were only minimally exposed.<br />
Merkel & Associates, Inc. 74