In a new paper published June 1 in Frontiers in Ecology and the Environment, scientists argue that environmental managers must broaden their focus from routine ecological monitoring to include social and economic factors if we are to protect ecosystems before they cross undesired tipping points.
A fashion for otter fur in the 19th Century has given researchers insight into how social changes can be a warning for ecosystems on the brink of collapse. In a new paper published today in the journal Frontiers in Ecology and the Environment, scientists argue that environmental managers need to broaden their focus from routine ecological monitoring to include social and economic factors if we are to protect ecosystems before it is too late.
As part of the study, the team at Lancaster University, the Center for Ocean Solutions at Stanford University, Conservation International and the ARC Centre of Excellence for Coral Reef Studies at James Cook University looked back into history to examine four iconic marine ecosystems that collapsed, investigating the social changes that preceded their demise. From the dramatic decline in Canadian cod populations to the decimation of Jamaican coral reefs, they found social factors from fashion to technological advances had a strong influence in driving environmental collapses.
For example, in the North Pacific, otter populations had been harvested by native hunters for thousands of years but were driven close to extinction by commercial hunting in the 1800s due to lucrative foreign markets for otter fur, which saw the value of otter pelts leap from a mere $15 to over $28,000 for a single pelt at the height of the market. The near extinction of otter populations created an explosion in urchin densities that diminished kelp forests and associated fish and invertebrates.
Sometimes ecosystems can undergo major changes in species composition, known as a regime shift, and although these shifts appear to unfold quickly, it often takes decades to get to that point. Undoing the damage is not easy.
"By examining these four iconic marine regime shifts, we found that in all cases a range of social factors set the scene for the ecosystem shift, ultimately driving them towards collapse," says lead author Christina Hicks of Lancaster University Environment Centre.
These social factors, which can include new technologies, opening of markets, demographic changes, or changes in governance structures or policy, often precipitate dramatic changes in how natural resources are harvested, thus escalating ecological change.
For example, fishing may increase steadily over time in connection with human population growth. Alternatively, fishing could increase radically in response to the introduction of a new, more efficient fishing technology or new connections to the global market.
In the sea otter example, market-driven harvesting accelerated in pulses when new markets in Russia and China entered the trade, ultimately leading the commercial extinction of otters throughout their range. Meanwhile, in the case of Jamaica’s coral reefs, overfishing and pollution were the main causes of ecosystem collapse, driven by the interaction of new markets, new fishing technologies, population growth and policy changes. The result was a system dominated by algae with coral nearly absent. The complexity of multiple interactive drivers highlights the importance of a diverse monitoring portfolio and cross-sectorial cooperation for sustainable environmental management.
Images: (Top) Sea otter fur trimmed winter court gown from Qing Dynasty, China (Garrett 2008). (Bottom) Sea otter off the coast of California (Mike Baird, Flickr Creative Commons). Overharvesting of Pacific sea otters for these luxury fur markets caused regime shifts from kelp-dominated ecosystems to sea urchin barrens.
After a regime shift, the services provided by the ecosystem are likely to have changed, with potential ramifications for the societies that depend on them. Furthermore, it may require considerable management effort to reverse such regime shifts, if it is possible at all.
Researchers say their new study underlines the importance of looking beyond ecological systems for clues, to understanding the root social causes that may forewarn when and where we are heading into dangerous waters. While recent research has identified certain ecosystem behaviors that indicate a system may be reaching a tipping point, these signals are often difficult to detect in enough time to prevent a regime shift.
“If we can tune into these social drivers we could potentially use them as an early warning signal of ecosystems at risk,” explains co-author Larry Crowder of Stanford University. “This is really important if we want to spot these changes before they happen and take action. Without knowing the root social drivers, we can get caught in a trap of treating the symptoms, rather than the underlying causes of the disease – this is critical for saving ecosystems before they are irreversibly lost.”
Indeed, the consequences of ecological collapse can be devastating and long lasting. Of the four cases discussed in this review, three have not recovered from their collapse (sea otters are thus far the one “success” story—as their populations have begun to rebound, kelp forests have come back along many Pacific coastlines). After an ecosystem has undergone a regime shift, it may be difficult to reverse not only due to ecological limitations, but also because social preferences may shift to favor new conditions (e.g., after the collapse of cod of the New England coast, lobster populations were able to expand their niche creating a new lucrative fishery).
Solutions for monitoring social drivers of change
Hicks and her co-authors describe three ways that social factors can influence ecosystem condition. One, a single social factor (like population growth) may act continuously but at different rates in different regions. Two, multiple social factors (e.g., population growth, economic growth, and land-use change) interact to catalyze change. Three, socio-economic changes (e.g., new technology, new markets) can have pulse effects that rapidly escalate change.
Based on these various types of social change, the researchers recommend key steps for incorporating social drivers into early-warning systems to help identify and counter regime shifts:
Invest in social monitoring. Environmental managers should work with social scientists and relevant government agencies to gather data on and monitor demographic, technological, market, cultural, and governance social drivers.
Specify social trigger points. Monitoring strategies should have clear specifications of what social driver information should trigger a response, whether it be reaching certain levels or thresholds of social change, or showing sudden variations in the rate of change, which could drive behaviors that would lead to a possible ecosystem collapse.
Identify policy responses. Each actionable trigger point needs to be associated with a suitable management or policy response, e.g. via access restrictions or market incentives, followed by ongoing monitoring and assessment of expected versus observed outcomes.
The root social drivers implicated in ecological shifts are often context specific, which will require managers to gain an understanding of their system’s ecology and of the history of associated human–environmental interactions.
Monitoring social drivers, specifying social trigger points, and identifying policy responses, will provide managers with the basis for a clear strategy for when action is possible, such as to regulate or close a market (e.g., for a specific species, as may have been appropriate for northern sea otters); ban or modify a technology (e.g., that spreads rapidly or affects critical ecosystem processes, such as those in the Canadian cod or Chesapeake Bay oyster fisheries); and amend or lift a policy (e.g., that creates unexpected or perverse behaviors, such as those enhancing fishing in Jamaica).
Ultimately, by recognizing how social drivers influence ecological outcomes, and monitoring those drivers, managers and conservation practitioners may have advance notice to anticipate ecosystem shifts as well as the capacity to offset those drivers, thus proactively avoiding or mitigating negative impacts to ecosystems and resource users.
Social drivers forewarn of marine regime shifts. C Hicks, Crowder, L, Graham, N, Kittinger, J, and Le Cornu, E (2016). Front Ecol Environ; 14(5): 1–9, doi:10.1002/fee.1284
Figure (below): Simplified timelines representing key changes in social drivers contributing to regime shifts in four marine ecosystems: (a) Northeast Pacific kelp forests, (b) Northwest Atlantic continental shelf, (c) Jamaican coral reefs, and (d) Chesapeake Bay estuary. *Otter pelt price converted to present-day US dollar values. **Relative cod price index based on Spanish and US data (1505–1892) from Vickers (1996).