| Summary | From high tide to low tide, health of the rocky intertidal along shorelines of California and offshore islands. |
|---|
| Project | SESMAD |
|---|
| Subtype | Natural Resource System |
|---|
| Sector | Marine protected areas |
|---|
| Commons Boundaries | Clear boundaries (3) |
|---|
| Explanation | Clear map indicating where this ecosystem is. Also fairly visible. Defined by four key zones:
The Splash Zone: Few organisms survive here. Those that can (e.g., barnacles, limpets and a type of green algae) are almost always exposed to the air and are rarely submerged by water.
The High Zone: Organisms that inhabit this zone are exposed to air more than 70 percent of the time and must develop adaptations to survive the long dry periods. For example, limpets, chitons and black turban snails form a watertight seal onto the rocks with their shells to protect themselves from drying out.
The Mid Zone: This zone is densely populated. California mussels often form large beds that provide important refuge and habitat for a variety of other invertebrates and algae.
The Low Zone: In this zone, organisms may be exposed to air just a few times a month so they are more resilient to waves and less resilient to air exposure. Inhabitants include the giant green anemone, the purple sea urchin, the sunflower star and the beautiful sea palm. |
|---|
| Environmental Medium | Oceanic |
|---|
| Explanation | Oceanic-Terrestrial boundary, but relates to more oceanic feature and dynamics in terms of ecosystem health (e.g. tides, ocean acidification, ocean temperatures). |
|---|
| Inter Annual Predictability | High (3) |
|---|
| Explanation | Ecosystem fairly constant, habitat does not move and home to many sessile animals. Studies have shown that the California rocky intertidal communities are fairly uniform and predictable (Connell 1972; Horn et. al 1983). Rocky shore habitats are very sensitive to pollution, oil spills, invasive species, and fluctuating air and ocean temperatures, providing some variables to take into account when predicting the commons. Rocky shore habitat assemblages appear to have less interannual variation than seasonal variation (Foster et al. 1988, Kinnetic Laboratories Inc. 1992). |
|---|
| Intra Annual Predictability | High (3) |
|---|
| Explanation | Fairly constant populations in a well studied ecosystem. Physical habitat always there (rocks along shore), difference is population composition. Seasonality has been observed in species population trends in the rocky shore habitats, leading to more predictability (Horn et. al 1983; Foster et al. 1988, 1991). |
|---|
| Commons Renewability | Renewable (1) |
|---|
| Explanation | Most species are fast-growing. |
|---|
| Productivity | Very productive (3) |
|---|
| Explanation | The California rocky shores habitat is one of the most diverse and productive marine ecosystems. More than a thousand species of invertebrates and algae live in Central California’s rocky shores habitats, and many fish, birds, and mammals predate on the species from these habitats (NPS, 2015). |
|---|
| Commons Accessibility | Very accessible (3) |
|---|
| Explanation | Users can very easily access these habitats, many times alongside coastal trails. Some areas are fenced off, while most are accessible from public land. |
|---|
| Commons Heterogeneity | High (3) |
|---|
| Explanation | Rocky shores are broken up by natural patches such as natural beaches and cliffs, while manmade structures have broken up the rocky shoreline. Rocky shores are connected by the California current, providing a sort of fast highway to connect the various strips of rocky shores. Within the ecosystem, rocky shores are well known to be very patchy and to respond in succession to events (Paine and Levin 1981; Sousa 1984, 1985). |
|---|
| Commons Spatial Extent | 2.1 |
|---|
| Explanation | Rocky shoreline is about 56% of the Monterey Bay Sanctuary shoreline (EIS, 2008), so covers about 156 miles, or 251 kilometers, of the Monterey Sanctuary.
While none of Cordell Bank is covered by rocky shoreline, the activities in the bank could influence this ecosystem, particularly oil spills.
Although a number has not been found, the amount of rocky shores along the Gulf of the Farallones coast was 22% before 2015. The expansion added about 68 miles along the shoreline, coming to a very rough about 170 miles of shoreline. If the 22% is extended to the expansion, this would come out to about 38 miles, or 61 kilometers, of rocky shoreline. This is a total of 194 miles, or 213 kilometers of rocky shoreline. If we say an estimate of average rocky shoreline width (from splash zone to low zone) of 30 feet, that is about .01 kilometers, which is a total of about 2.1 square kilometers. |
|---|
| Technical Substitute | Yes |
|---|
| Explanation | Riprap or Bulkhead can be used, but it is not as effective at overall ecosystem health and is typically not used in this area. |
|---|
