Photographing barnacles, counting seastars, measuring limpets—this is how volunteers spend their afternoons during low tide at Cabrillo National Monument. Plus they interact with the many tens of thousands of visitors that go to this park each year, educating them about the plant and animal life in the tidepools. Most importantly, volunteers enforce “tidepool rules” which ensure the tidepools are protected from over-visitation by humans. Volunteers have contributed thousands of hours to the National Park Service, providing a critical, but unfunded service. Data collected by volunteers follows MARINe protocols and is analyzed by MARINe scientists.

This careful data collection by volunteers overseen by the Cabrillo National Monument biologist, Ben Pister, and their direct interaction with the public to control poaching at the Park has led to great success. One direct indication of this success is noted in the large size and number of owl limpets along the shoreline. A recent peer-reviewed paper published in Marine Biology¹, analyzed the impacts of humans on the population size trends of giant owl limpets at MARINe sites throughout Southern California. This paper showed that, due directly to the volunteer and ranger oversight at Cabrillo National Monument, owl limpets are being protected. It is reasonable to assume that this same effort likewise protects other important tidepool animals and plants at the park.

So, the next time you are greeted at Cabrillo National Park by a volunteer or ranger, or are instructed by them to walk carefully and not put animals in your backpack, thank them for the work they are doing to protect the resources at the park. Know that it is time well spent.

1 Sagarin, R.D., R.F Ambrose, B.J. Becker, J.M. Engle, J. Kido, S.F. Lee, C.M. Miner, S.N. Murray, P.T. Raimondi, D.V. Richards, and C. Roe. 2007. Ecological impacts on the limpet Lottia gigantia populations: human pressure over a broad scale on island and mainland intertidal zones. Marine Biology 150:399-413.