Temperate Coastal Ecology

Temperate Coastal Ecology

Decadal Changes in Invertebrate Communities

We have been able to sample benthic invertebrate communities along the California continental margin and most bays and estuaries. We were able to resample some of these communities 30 years after the first samples were taken thanks to support from the Monterey Bay National Marine Sanctuary and the Elkhorn Slough National Estuarine Research Reserve. Decadal changes in Elkhorn Slough were related to accelerating wetland erosion. In contrast, the surf zone, the low intertidal and shallow subtidal sandy beach, was colonized by a warm water species (the amphipod crustacean Americhelideium shoemakeri) over a 30 year period. No warm water species were found beyond the surf zone to water depths of 30m. Finally, from 10-30m, the Pacific Decadal Oscillation (PDO) correlated with deeper subtidal sandy bottom invertebrate community changes, but there was no signal from the PDO in the infauna of the surf zone or in Elkhorn Slough. A list of the benthic community data sets is here.

Monterey Submarine Canyon

Monterey Canyon experiences periodic sediment failures that open up new habitat space by removing the existing benthic community. The frequencies of these natural disturbances are partially dependent on storm activity and sedimentation rate, and we expect native communities to be evolutionarily adapted for periodic disturbance. In contrast, benthic disturbances in San Francisco Bay are driven by economic factors rather than seasonal ones. Dredging and filling activities over the last century have created an unstable, unpredictable system where invasive species may have an advantage over native communities.

Monterey Bay Deep Sea Megafauna

For this study, we used remotely operated vehicles (ROV’s) to produce continuous video footage, quantitative video samples, and still photos of benthic megafauna on the seafloor. We also used photoquadrat analysis to document bottom habitat types (based on physical and biological features of the seafloor), allowing us to develop a benthic classification system to be used in future studies. Our vessels were equipped with either a Phantom DS4 ROV for depths to 450 m), or the Remora, an ROV designed for deeper depths. More than 150 hours of digital video tape and thousands of still photos were made during these surveys.

California Legless Lizard Relocation Project

The California Legless Lizard (Anniella pulchra) is by nature an elusive creature and difficult to study because they live underground. In 1997, early surveys at the new MLML building site indicated that there were legless lizards present and experts thought that we might find a couple of hundred of them in the construction area. These animals are a designated California Species of Special Concern for two reasons; they have very specific habitat requirements meaning that there are very few places where they can live, and their specific coastal dune habitat is subjected to continual human impacts. Under an agreement with the California Department of Fish & Game that included specific permit requirements to mitigate any impacts to the lizards, the labs made plans to remove the lizards and translocate them to the adjacent dunes. The dunes, which surround the labs on three sides, were to be restored as native habitat, and harmful iceplant, radish, ripgut grass and other weeds were replaced with native bushes. This work began in 1997 on six acres, and continues to provide high quality habitat to a long list of native animals. Two federally protected plant species thrive there now (Chorizanthe pugens pugens and Gilia tenuiflora arenaria).

In 1997-1998 we carefully hand raked every inch of the construction zone. To everyone’s amazement, over 3500 Anniella were recovered. This project provided a great research opportunity to learn about the longevity, movement, population density, and microhabitat choices of Anniella. Our re-building agreement also included a stipulation that we closely track the health of translocated lizards for a five-year period. We used new technology as a tool for tracking the movements and habits of our population of animals. We placed small (rice grain-sized) microchips called PIT tags (Passive Integrated Transponders) in about 600 lizards, then released them. With a special modified reader that looks a lot like a metal detector, each unique PIT tag can be read to a depth of 11.5 cm below the soil surface. We were able to survey the hill and find lizards in their underground habitat without recapturing or disturbing them. Translocation efforts were very successful and have provided a model for other similar projects. Tagged animals continued to be found for at least decade, and we estimate that they were a minimum of 4 years old when tagged and released.

McWay Landslide - Big Sur, California

Manipulated and natural landslides are common disturbances along the slide-prone coast of California. They can affect marine intertidal and subtidal communities by direct burial, scouring by coarse sediments, and deposition of fine sediments. They also may increase turbidity in marine waters. The McWay landslide, on the Big Sur coast, caused by heavy winter rains in 1992-93, closed Highway One for almost two years. It is the largest landslide manipulated by CalTrans in recent years. In order to reopen the highway, CalTrans removed over three million cubic meters of sediment and debris. Much of the sediment was deposited onto the face of the slide on the west side of Highway One where it continues to erode and slump into the ocean.

Since 1986, the Benthic Lab group has investigated the movement of this sediment into the ocean and its impacts on nearshore marine communities. Surveys of biological and physical conditions in the slide affected areas, (terrestrial, intertidal and subtidal) are conducted annually and will continue through 1998, providing an important long-term data set. Biological communities are assessed by photographic and video techniques. The seafloor affected by the slide has been mapped as to sediment type and distribution through the use of sidescan sonar and grain size analyses. Profiles track topographic changes in beach and intertidal areas. Additionally, baseline biological data has been collected to describe other slide-prone sites in the region. These data are essential in developing environmentally sound and defensible highway construction and maintenance strategies.

Lone Tree Slide - Ecological Mitigation, Monitoring, and Restoration

As a result of the Loma Prieta earthquake in October, 1989, the Lone Tree Slide, closed Highway One between Muir Beach and Stinson Beach along the northern California coast. The road was reopened in June, 1991, after over three quarters of a million cubic meters of soil and rock were removed from the slide face. The slide material was disposed into a large fill on the west side of Highway One. The seaward edge of the fill extended over 60 meters into the ocean. As a result of the slide, three major projects were directed to the Benthic Lab group: Highway One – Lone Tree Slide Monitoring, Big Lagoon Restoration, and Bolinas Lagoon Restoration.

Highway One - Lone Tree Slide Monitoring, Marin County, California

The Lone Tree Slide baseline and monitoring projects commenced in 1990 and ended in 1996. The long term ecological study included one year of baseline characterization of the slide area’s physical and biological environments. The slide was then manipulated by CalTrans to remove sediments closing Highway One. Five years of post-manipulation monitoring followed. The Benthic Lab group’s objectives were to document the physical attributes and ecological affects of the slide and to provide information useful towards the management of slide prone regions of California.

Physical information collected included: measurements of the limits, velocity and hydrologic conditions of the fill, beach sediment and rock movement, nearshore plume movement, suspended stream sediment, meteorological conditions, and seafloor mapping, morphology and bathymetry. Biological information included surveys conducted to characterize and monitor rocky intertidal and subtidal communities, intertidal sand beach communities, subtidal sand communities, and slide area vegetation.

Big Lagoon Restoration, Muir Beach, California

In 1992-94, as mitigation for the fill disposal from the Lone Tree Slide, CalTrans provided funds for restoration of the historic wetland and riparian system of Big Lagoon at Muir Beach. As part of the preparation for the development of restoration alternatives, the Benthic Lab group researched historic and current biological conditions of the site. Historic information was collected from archival sources. Current biological conditions were obtained from surveys to describe and document bird, amphibian, reptile, mammal, invertebrate, fish and vegetation communities. From these data, the Benthic Lab group predicted future conditions under current environmental and sociological regimes as well as identified biological restoration opportunities for the site. Restoration alternatives were presented to Golden Gate National Recreation Area for their implementation.

Bolinas Lagoon Restoration, Bolinas, California

In 1992-94, as mitigation for the fill disposal at the Lone Tree Slide, CalTrans provided funds to remove a causeway and fill disposal site in Bolinas Lagoon, Marin County. It was anticipated that these actions would increase the tidal prism, and restore natural hydrodynamic functioning and fishery habitat of the lagoon. The Benthic Lab group performed a year’s baseline surveys describing benthic invertebrates, birds, marine mammals, fishes, and plants prior to the removal of the causeway and fill. Post construction monitoring continued for an additional two years to track the effects of the mitigation.  

Wilder Ranch Restoration Plan, Santa Cruz County, California

Wilder Ranch State Park includes almost 5000 acres of coastal habitat and recreational area with about 900 acres in agriculture, some cattle grazing and a culture preserve. Approximately 110 acres were identified to be restored to historic habitat conditions and native vegetation. The area had great potential as a model for the restoration of coastal wetlands. It included Wilder Beach, saltmarsh, grassland, and riparian habitats, as well as three agricultural fields. From 1992 to 1994, the Benthic Lab group researched historical land use, and past and present physical and biological conditions of the Wilder Ranch restoration area. They proposed and designed restoration alternatives. The information was presented as a plan which the California Department of Parks and Recreation used to develop and implement the restoration of the park. The restoration has been extremely successful. Since 1994, the agricultural fields have been returned to wetland and riparian habitats with their native tree, shrub and plant species. Wetland birds, and hawks nest in habitat that formerly was farmland. Red-legged frogs and other wetland animals have moved into the area. The riparian corridor along Wilder Creek has been widened to about 100 feet. Dogwood, alder, cottonwood and willows planted in 1994 have grown at a good rate, with some trees already over twenty feet tall. The adjacent upland restoration also has been successful. With continued monitoring to eradicate pest plant species such as hemlock and thistle, Wilder Ranch will become one of the showcase coastal wetland restoration sites.