PRBO is extremely fortunate to be joined by Dr. John Wiens in the new post of our Chief Conservation Science Officer. One of North America's preŽminent ecologists (some biographical data appear at right), who brings outstanding new leadership to PRBO's growing research programs, John is also a wonderful speaker and writer. In this special, single-feature issue, John Wiens offers a perspective on conservation science and PRBO.—Editor
The world is changing, rapidly. A trite observation, perhaps, made by the elders of every generation over time immemorial. But nonetheless true.
Conservationists are particularly concerned about the changes that affect the status of the Earth's biological diversity. Natural habitats are disappearing or being fragmented into tiny remnants at an alarming rate. The declines in abundances of many species are unprecedented in modern times. More and more species are winking out of existence, some undoubtedly before we even knew they existed. And projections of the future don't offer much relief. Confronted with rapidly deteriorating biodiversity, what is a conservationist to do?
More to the point, what should an organization like PRBO Conservation Science do?
PRBO is dedicated to conducting scientific research and public outreach on birds to advance the conservation of biodiversity. PRBO began (as Point Reyes Bird Observatory) as a bird-banding operation. Over the years this work expanded, geographically and conceptually, to encompass the sorts of long-term assessments of avian population dynamics and demography for which PRBO is famous. This work, in turn, lies at the foundation of our work in habitat restoration, ecosystem-based management, policy, and education in terrestrial, wetland, and marine ecosystems, all of which extends well beyond our California base. It's been a successful recipe, one that has helped foster public and political support for conservation and guide management and policy. But is it sufficient, or even relevant, to the changing world that is upon us?
Conservation has traditionally been something of a status quo discipline, aimed at preserving or restoring nature as it is or as it was in the recent past (generally what we remember it being when we experienced it as children). Recovery efforts for endangered species strive to return populations to some former steady state. Habitat restoration aims to recreate some former condition that existed before an area was disturbed, usually by human activities. Yet historical ecology tells us that things have never been the same for very long—there is no steady state of nature; the "balance of nature" is a myth. Examples are legion. Eastern forests are not what they were before a blight eradicated chestnuts, the distribution of piñon pine and juniper in the Southwest was quite different a few hundred years ago from what it is now, cattle egrets did not occur in North America a hundred years ago, and of course glacial advances and retreats during the Ice Ages transformed the American continent and reshuffled its biota. Not only do we live in transitory times: times are always transitory.
The difference now is that the changes are more rapid than in the recent past. They are often dramatic, raising the likelihood that hidden thresholds or "tipping points" will be passed and ecological systems will suddenly undergo irreversible changes into something different. And they are increasingly driven by global rather than regional or local forces. The nutrient balance of the Amazon Basin is affected by the transport of nutrients from dust storms in Africa. Air pollution created in China doesn't stay in China. The demand for biofuels for transportation in developed and developing countries affects the conversion of rainforest to palm-oil plantations in Indonesia, of the Brazilian Cerrado to soybeans and sugar cane, and of corn produced for food to corn produced for ethanol in the American Midwest. Land that was designated for wildlife habitat under the Conservation Reserve Program in the United States is now being converted back to row-crop agriculture, driven by high corn prices, which are driven by the demand for corn ethanol, which is driven by growing and shifting global demands for fuel.
And hanging over it all is the reality of global climate change, which is already altering the distributions of some species, the breeding times of songbirds, the flowering of Washington, D.C.'s fabled cherry blossoms, and salt-water intrusion into coastal wetlands as sea levels rise. The dramatic expansion of mountain pine beetles in British Columbia (and now Alberta), with its devastating effects on boreal forests, is associated with warming winters that have passed a threshold that formerly kept the beetle populations in check.
|Analyzing "conservation futures" might regard the Acorn Woodpecker as a focal species in oak woodlands...|
|...and the American Avocet (chick, above) within a group of tidal marsh birds. PRBO photos.|
It has become clear that the future will not be like the past. Conservation as usual, conservation that does not consider future probabilities, will be insufficient. The conservation community must shift its thinking about conservation, from protecting and managing what we have now to assessing, as well, what the future is likely to hold and how we deal with changing environments and a changing natural world. As conservationists, we cannot control the forces that drive future climate change or that create the global economic and political pressures that affect future land use. But we can anticipate how these forces may affect local and regional environments and populations of birds and other organisms. We need to develop programs on what I call "conservation futures" to assess how climate change and changing land uses will affect ecological systems.
This shift in thinking is already well underway at PRBO. PRBO scientists are using information derived from our own work and that of partners to model current distributions and habitat associations of a core group of bird species. The results are being used in conjunction with model projections of future climate change, vegetation change, and land-use change to construct scenarios of future distributions of these species in California. This information, in turn, is enabling us to identify "hotspots" where distributional shifts for particular species are likely to be dramatic (or "coldspots" where distributions may remain stable). By extending the analysis to functional groups of birds (such as woodpeckers or ground-nesting species) or the entire assemblage being analyzed, we can determine where turnover in species composition is likely to be greatest, or where overall species richness will increase or decrease. The areas identified through this modeling may enable conservationists and resource managers to target their efforts where they are most needed or are likely to have the greatest return on investment. The next step will be to couple such model projections with PRBO's long-term data on songbird reproduction and survival, to move beyond an approach based largely on habitat associations and probe the underlying mechanisms, as well.
|PRBO's signature long-term research includes 40 years studying Common Murres and other Farallon Island life. PRBO photo.|
PRBO's marine program is also using our long-term studies to develop ways of assessing future conditions. Oceanic ecosystems are likely to undergo major changes associated with climate change; increasing ocean acidification is only one example. These changes are superimposed on the varied cycles of ocean dynamics: El Niño/La Niña Southern Oscillations on a scale of years, Pacific Decadal Oscillations on a scale of decades, and the like (see Observer 138, Fall 2004, online at www.prbo.org). Understanding how these cycles influence seabird populations is a key to projecting how future changes are likely to play out. By extending our marine work beyond the Farallon Islands and by encompassing studies of the prey base, PRBO's work on seabird demography can now be linked to the broader food-web dynamics of the marine systems that support the birds (as well as salmon!). This work can form an important contribution to the development of marine protected areas and fisheries management under future conditions.
PRBO is also actively engaged with partners in assessing conservation futures in other areas. Tidal wetlands, for example, may play an important (and only recently recognized) role in carbon sequestration. Documenting how and where this role intersects with the value of areas as habitat for breeding birds or migratory shorebirds may be a key to developing landscape-level plans for optimizing the management of large tidal wetlands and shorelines on the Pacific Coast, building on the spatial optimization modeling we have conducted for South San Francisco Bay (Observer 136, spring 2004). In the Central Valley of California, changes in water distribution and availability associated with changes in mountain snow packs and growing domestic and industrial demands are likely to affect the California rice industry, which creates wetland habitats that support breeding and migratory birds. Management of riparian habitats on major rivers and their upstream tributaries will become increasingly important in controlling and conserving water flows with changes in climate. Integrating the value of bird conservation with the other values of riparian vegetation will be critical to the formulation of comprehensive, watershed-scale water management.
Looking beyond certainty
Focusing on the future does not mean that the past is irrelevant. It's been said that those who ignore the past are condemned to repeat it. Given the looming changes in climate and land use, it's not likely that the past will be repeated even if we do ignore it. But we can learn much from the past. By looking at the past using PRBO's long-term data and analyses, we can begin to determine how and why species and ecological systems have varied and how and why they are changing. This is essential understanding if we are to anticipate future changes and develop responses that will soften their impacts on biodiversity.
The good thing about looking to the past to determine what we do in the present, as has been the tradition in conservation and management, is that we know (or think we know) what has happened in the past. Hindsight is 20-20. Using model projections of the future to determine what we should do now, on the other hand, is tainted by uncertainties. This is uncomfortable to those who expect science to provide certain answers, and it is uncomfortable to scientists who have been trained to minimize uncertainty in their work (that, after all, is the foundation of experimental design and statistics). Clinging tenaciously to rigid standards of certainty, however, may marginalize science in situations where conservation or policy decisions must be made quickly. Dealing with the future entails a willingness to accept and be comfortable with more uncertainty. We can use the knowledge that comes from long-term studies of bird populations, however, to reduce the uncertainty as we go along. This is why it is so important to continue to monitor changes in bird populations and their environments, so we can improve our model projections, see trends as they develop, anticipate looming tipping points, and plan for the changes that may be inevitable.
PRBO has come a long way from a fledgling bird-banding operation (or an operation banding fledglings). It has a strong foundation of actual data, rather than hunches or guesses, on which to build. This work will continue, but more and more in the context of conservation futures. There is no other way.