2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Management of the California least tern and western snowy plover nesting sites is expected to be
adaptive due to enhancement of the Bolsa Chica area and the creation of new nesting and foraging
areas. Management recommendations for 2008 were made to increase reproductive success and to
enhance the newly created nesting sites (Knapp and Peterson, 2008) and are summarized below.
There are currently at least 6 species nesting on NS1 including black skimmer, elegant tern, royal tern,
Caspian tern, as well as the western snowy plover and California least tern. This high-density nesting
may have some benefits but appears to be highly detrimental to least tern and snowy plover nests and
chicks. This problem requires long-term management that would address overcrowding and its effect
on listed species, as well as a review of monitoring methods that would minimize disruption of this
large nesting colony. For the 2008 breeding season, roof tiles were placed on the site. This
management aided in the increased survival of chicks on the site through protection from both
predation and trampling. Increased cover on NS1 in the form of vegetation and debris would decrease
least terns and snowy plovers chick exposure to predators, lowering predation and aiding in increased
foraging areas for snowy plovers. NS2 is not used by any nesting avian species and NS3 is currently
being utilized by the snowy plover. These sites need to be assessed to determine how they can be
managed and for what species. Finally, there needs to be improved water management in the Seasonal
Ponds. Several zones, normally utilized by the snowy plover for nesting, were not available in 2008
due to seasonal flooding and subsequent poor drainage.
Recommendations
• Increase cover on NS1 in the form of vegetation and debris.
• Assess sites NS2 and NS3 to determine how they can be managed and for what species.
• Improve water management in the Seasonal Ponds.
1.7. NON-NATIVE INVASIVE SPECIES
An awareness of the importance of tracking the arrival and spread of non-native species has increased
in recent years, particularly with the discovery of the invasive non-native seaweed Caulerpa taxifolia
in nearby Huntington Harbour and in Agua Hedionda Lagoon in San Diego County. Early detection of
some species of invasive plants and animals may allow the opportunity for quick and economical
response activities. These species may include non-native seaweeds such as Caulerpa spp., Sargassum
filicinum, and Undaria pinnatifida, or terrestrial weed plants such as pampas grass or Arundo, as
mentioned above. However, there are other non-native species that are already proliferating in
regional coastal embayments and are likely to invade the tidal areas of Bolsa Chica at some point in the
future. While options to restrict these species from Bolsa Chica are limited, keeping good records on
the time of arrival and the degree of spread can be helpful for understanding the threat posed by these
species to Bolsa Chica, as well as for the general body of knowledge about these species.
During the 2008 monitoring several non-native marine species were observed. At least two non-native
tunicate species were captured in the restoration areas: Styela plicata and S. clava. These species are
common occurrences in southern California and both have been documented to impact native species
of tunicate by competing with them for space or food, or by impacting the reproductive success of the
native species by consuming the planktonic larvae before they settle. Both species were first found in
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