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Shifting Baselines and Ecological Detectives

David A. Bainbridge In ecological restoration and natural resource management in general, one of the biggest problems is that of shifting baselines. What does that mean? It is the human response to think what we have seen is somehow normal. As resources diminish and decline each generation accepts that what used to be seen (20 or 30 years ago) was normal and that the decline since then was minor or that a modest improvement was remarkable. Four examples illustrate this clearly — sea otters and their ecosystem impact, beaver, salmon, and desertification.


Sea otters and kelp are tightly linked. Sea otters control predators, like sea urchins, that eat kelp. If the otters are removed it is possible to see total devastation and the creation of a barren ocean floor with only urchins where once a kelp forest lived. With less kelp or no kelp the fish and shellfish decline or disappear. Yet despite the evidence of tremendous kelp forests along the coast of California in 1800, the management of resources has rarely acknowledged this loss, which some suggest has been 90% of the original extent. Biologists who grew up without kelp on their coastline still sometimes consider it normal and that it will continue to be so. They fail to consider why abalone, clams and fish are scarce today. A kelp and otter restoration program could make a big difference — despite the challenges of climate change. After kelp had been gone for more than 20 years, biologist Nancy Caruso (https:// and many others have restored some of Orange County’s kelp forests. With help from more than 5,000 kids growing kelp in their classrooms and 200 volunteer divers to plant it, they have returned this precious resource to parts of the the coast. Now they just need to return the otters to help protect and maintain the kelp. Further north in Monterey Bay the otters played a critical role in restoring the kelp forest to health. A full-fledged kelp and otter restoration project for the entire fur coast, from Baja California to Alaska, would put tens of thousands of students to work on an important project. With the help of divers and marine biologists, these vital kelp forests and resources could be repaired . An added bonus would be the return of fish and shellfish for recreational harvests.

BEAVER Beaver play an essential, invaluable role in stream stability and enhance biological productivity. They build dams that improve water storage, summer stream flow, trout and salmon survival, and increase biodiversity of plants, birds, amphibians and mammals. Beaver were once almost everywhere on every stream in the West, but beginning in the late 1700s they were being killed for their fur.. Beaver are very vulnerable to trapping and easily wiped out. In 1829 for example, fifteen hundred beaver pelts were collected at the Mission San Jose (Fremont, CA). In 1840 four thousand were taken in the Bay Area. Very capable biologists like Joseph Grinnell and Donald Trappe failed to recognize this — and their maps of historic distribution of beaver in California were incorrect. They had no idea of the tremendous impact trapping had on beaver populations and distribution. Rick and Chris Lanman and colleagues helped correct this misunderstanding by reviewing historical records, museum collections and other on the ground research. This completely revised the map.

Returning beaver to more streams is desirable for many reasons. The dams trap sediment, hold back floodwaters, improve stream flow, keep water cooler, and trap nutrients. The results can be amazing (see page 107 in Fur War Volume 1. Although check dams that do this can be built by humans (and some ranches in the SW have built thousands) beaver are less costly and the beaver work hard to maintain their waterworks year after year.

SALMON RUNS Salmon are so scarce now it is hard to realize how common they once were in the West (and the East). When Lewis and Clark were exploring the Columbia and Snake River basins in 1805, they reported native people catching massive quantities of salmon; 10-16 million fish by current estimates. Salmon was a dietary staple of the First Nations. Large, tasty, and with 4 or even up to 7 runs a year they were available at predictable times and places. Salmon runs on the Sacramento and San Joaquin Rivers were so enormous it was said you could walk across the river on their backs without getting your feet wet. Most salmon populations in the west were quickly diminished or destroyed after the Gold Rush and settlement. They were killed by over fishing (20 canneries on the Sacramento River alone), pollution from gold mining (mercury used to process gold ore plus 1 billion tons of sediment from hydraulic mining), pollution from saw mills, and water diversion and dams for mining, logging and farming. Later, paper mills added new often toxic waste and killed salmon and other aquatic life. The final straw was the construction of huge dams for hydroelectricity and for barge and ship traffic. Since European settlement, 9 out of 10 wild salmon runs and 100 distinct salmon stocks have disappeared from the Pacific Northwest. Three times that many are at risk of disappearing.

Shifting baselines have been a persistent problem in discussion about salmon. As Daniel Pauly put it, “each generation of fisheries scientists accepts as baseline the stock size and species composition that occurred at the beginning of their career.” The downward slump from generation to generation has gotten to the point where fisheries managers may be excited when the wild salmon on a stretch of river increase to 1,000, up from an appalling low of 500, in a place that once probably supported 500,000 fish or more. In the 1950s the Middle Fork of the Salmon River still had 50,000 fish, but no longer. It has not gone well, as a more recent chart of salmon redds (nests) on the Upper Salmon River shows. If we put the salmon river data on graph paper at this scale we would need a sheet of paper more than 15 feet tall. This population of salmon may well go extinct. The baseline shift needs to go back to the incredible runs of the rivers before the Europeans arrived. We have to resolve to to more to restore and protect the wild salmon. Returning beaver to more streams will help. We also need to remove dams and other obstacles that block the salmon.

DESERTIFICATION The West has been transformed since settlement. Very few small pockets of native vegetation remain. Trees have been stripped from the hills and once grassy areas are barren after being over- grazed for 100 years. Unsustainable farming methods have exhausted soil organic matter and left thousands of acres polluted with salt and alkali from irrigation. Wicked invasive plants have further degraded the land. Yellow star-thistle, for example, is estimated to infest over 14 million acres in California.

Restoration work has too often neglected to look back in time before the ranchers and farmers arrived to see what the baseline should perhaps be. My parent’s ranch in SW Colorado was a perfect example. Their plot of land had been the headquarters for a ranch for more than 80 years when they bought it. It had been overgrazed for most of those years, as had the surrounding region. Range experts and biologists failed to consider what it had once been like. Early descriptions were striking, with rich, living, soil-protective crusts, grass taller than a horse’s belly, fields of wild flowers, and clear water in streams. A far cry from dry, eroded arroyos, salt and alkali crusted pastures, weedy species (most with thorns or poisonous) and scattered shrubs. After 40 years with minimal grazing, some parts of my parent’s pasture had returned to health—but the more abused areas would take centuries or/and an investment of time and money to restore.

SHIFTING BASELINES We believe what we see and experience and this leads to problems of shifting baselines. This failure to consider the past leads to persistent problems in resource management. Baseline shifting is dangerous and needs to be more openly discussed. We need to seek healthy and resilient ecosystems, not simply less bad messes. A historically informed approach to site-specific restoration can help practitioners and affected communities confront the social and political dimensions of environmental change. This is not easy because ecosystems and cultural practices are complex, interlinked and have always changed. Now this is further complicated by the impact of global climate change. Doing the detective work to establish better baselines is interesting and challenging. Often the best work is done by people who don’t know the conventional answer. The outstanding work on beaver was done by a doctor/biotechnology entrepreneur not a wildlife biologist. You an become an ecological history detective too (more details in a future blog).

FURTHER READING -— see the book Fur War in the West 1765-1840. and supplemental material at SEA OTTERS AND KELP Sea otters and kelp

BEAVER Chris Lanman., K. Lundquist, H. Perryman, J.E. Asarian, B. Dolman, R. B. Lanman and M. Pollock. 2013. The historical range of beaver (Castor canadensis) in coastal California and the San Francisco Bay Area: An updated review of the evidence. California Fish and Game 99(4): 193-221. Rich Lanman, H. Perryman, B. Dolman and C. D. James. 2012. The historical range of beaver in the Sierra Nevada: a review of the evidence. California Fish and Game 98 (2):65-80. SALMON Mark Kurlansky. 2020. Salmon: A Fish, the Earth, and the History of Their Common Fate. Patagonia Books. The appendix on Pacific wild salmon is excellent. DESERTIFICATION David A. Bainbridge. 2007. A Guide for Desert and Dryland Restoration. Island Press. Stephen Mitchell and David A. Binbridge. 1991. Sustainable Agriculture for California: A Guide to Information. University of California, Division of Agricultural and Natural Resources. Publication #3349 OVERVIEW Peter S. Alagona, John Sandlos and Yolanda Wiersma. 2012. Past Imperfect: Using Historical Ecology and Baseline Data for Conservation and Restoration Projects in North America. Environmental Philosophy. 9(1):49-70.


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