PRBO biologists have gathered data on island wildlife in a consistent fashion throughout each season, year in and year out, since the program's inception in the late 1960s. We maintain a year-round field station for science and stewardship on Southeast Farallon Island, in cooperation with the U.S. Fish and Wildlife Service—an extraordinary opportunity.
|Northern fur seal was extirpated by past fur hunters and recently reestablished on the island.|
We consistently monitor the island's plethora of seabirds—storm-petrels, cormorants, alcids (puffins, guillemots, auklets, murres) and gulls, 11 species in all—and document their feeding interactions within the ocean ecosystem. We also study the island's changing seal and sea lion populations; record extraordinary occurrences of migratory songbirds; take the pulses of ocean dynamics such as sea surface temperature; and much more (some highlights below). The constancy of our data gathering over time has given PRBO a rare and valuable perspective on natural systems. Long-term research of this sort is most uncommon.
On the Farallones and perhaps a half-dozen other island systems worldwide, where seabird studies have continued for at least 30 and as long as 50 years, scientists can ask—and really begin to answer at meaningful levels of detail—how things are changing over time.
|Common Murre pair and (below) a view of their crowded colony. This Farallon population has responded dramatically to natural and human-caused impacts; high numbers today reflect the "fat" ecosystem of 1999–2002. Photos by David Gardner (above) and Anne Schmidt (below).|
In fact, we can ask the question in a more compelling way: "How is the environment changing in relationship to global warming?" This is essentially a research question—posed at an appropriately long time scale.
The vantage point provided by a small rocky outpost at the edge of the continental shelf enables PRBO to discern the workings of a marine ecosystem and discover some of its rhythms of change. With the passage of time, the system itself has shown us which new questions to ask.
Initially, we aimed to uncover the basic life histories of Farallon seabirds. Sampling from the island's vast populations, we asked, "When and how successfully do they reproduce?" and "What are their foods, and how great are their foraging efforts?" In 1990, based on our first 12 years of study, PRBO produced a landmark book on Farallon seabirds, detailing their adaptations to the variable marine ecosystem in the California Current.
Meanwhile, a series of warm-water years (especially in the 1980s and 1990s, when extreme "El Niño" warming events were frequent) was giving way to a sequence of cold-water (highly productive) years in the late 1990s. We then learned that variability occurs on greater scales than year-to-year or even decade-to-decade: the evidence points to an ecosystem that is perturbed, perhaps constantly!
The system also has "memory" of sorts. When upwelling of cold, nutrient-rich water in spring is strong for several years in a row, the ocean ecosystem primes itself, much as an animal does when it puts on fat. Common Murres on Southeast Farallon Island, bolstered by great reproductive success in the years 1999–2002 and evidently flourishing on alternate food supplies, now number roughly a quarter-million!
Lately, through our scientific lens, we have seen new kinds of change that may be explained in the context of global warming. In the critically important California Current off our coast, the marine food web has broken down in unexplained ways. Shortbelly rockfish, important food for most seabird species that nest on the Farallones, once were common but now have essentially disappeared.
The oceanic spring season when cold-water upwelling usually fuels the seabird breeding cycle appears to be shifting. Common Murres are timing their breeding earlier than in the past.
Perhaps most alarming, the regular hordes of "krill" (tiny shrimp-like crustaceans)—crucial to the food web supporting salmon, blue whales and other consumer organisms—has gone missing in the past two years.
Among Farallon seabirds, the Cassin's Auklet is unusual in that it feeds primarily on krill, not fish. This species' total nesting failure in 2005 (repeated to a lesser degree in 2006) was astonishing and unprecedented; it also coincided with extraordinary ocean-atmospheric patterns.
Farallon auklets are now the focus of worldwide attention, as scientists interested in marine ecology, fisheries, atmospheric patterns and oceanographic variables take note of conditions in the California Current.
|The cast of characters on Southeast Farallon Island includes: Pigeon Guillemot, a diving seabird that depends on nearby rockfish supplies.|
The span of PRBO's Farallon work to date falls within the half-century during which humans essentially industrialized the globe. Humanity's capacity to change the environment has become a major factor for setting new directions in marine ecology research on the Farallones and beyond. Having documented four decades of response by seabirds and marine mammals to environmental fluctuation (some of it human-caused)—and also having learned much about these consumers' feeding interactions in the marine ecosystem—PRBO has laid the groundwork for detecting and interpreting what's to come.
Given the increasing rate and scale of change, a major concern after 40 years of Farallon work is how much we do not know. To gain an even wider, more focused view of natural systems, PRBO will keep increasing cooperative efforts with both marine resource managers and environmental scientists of many disciplines. With our research emphases on feeding interactions and oceanographic dynamics, we are leading cross-disciplinary scientific discussions and translating seabird research for the management of sustainable fisheries.
Predictive models, which provide an entirely new level of understanding of environmental trends, will be another invaluable use for the wealth of Farallon Island data.
The outlook beyond the immediate future, to a horizon perhaps four decades hence, includes collaborative work on a much larger scale than ever before. "Big science" will be essential in order to address the questions facing us today, but such effort will call for major shifts in policy priorities and unprecedented levels of funding.
|Cassin's Auklet (chick in hand), a species whose recent breeding failures bespeak unprecedented ecosystem change.|
Given the scale and pace of change now in progress, findings from "natural laboratories" like the Farallones—until now seen as distant and peripheral—could become central influences in our society. Demand for what can be learned from extraordinarily long-term study of ecosystems will likely increase.
The work of PRBO biologists may well expand beyond science to include the role of emissaries, interpreting our findings in widening circles. Places like the Farallon Islands where scientists can take the pulse of natural systems—measuring their health—will likely grow ever more vital to human understanding of our rapidly changing world.