By Tundi Agardy, Contributing Editor, MEAM. Email: tundiagardy [at] earthlink.net
In an ever-changing world, with a burgeoning human population and growing demands for goods and services, who could argue against maximizing the resilience of the natural systems on which we depend?
The real question is whether we can.
Managing for resilience is one of EBM's main goals. As our understanding of EBM has matured, this goal has encompassed not just ecosystem resilience but social resilience as well. We could not hope for more than to increase the ability of ecosystems and human communities to cope with the vagaries of climate change and other stressors. Resilience encompasses robustness, stability, and health. Pretty in its logic, resilience remains elusive nonetheless.
Here's the catch: even the most predictable systems - e.g., coral reefs and associated coastal communities - are hugely complex. Some of the most basic tenets of ecological understanding have been disputed and remain controversial. Are there alternative stable states, such that reefs under pressure permanently switch from coral-dominated to algal-dominated? If so, can we identify thresholds that should be avoided? These are not esoteric questions - they underlie much of the management planning, evaluation of trade-offs, and scenario development that form the basic elements of EBM today. The understanding of resilience is, paradoxically, getting more complicated as our knowledge increases, especially as we now (rightfully) consider not only ecosystem resilience but also social resilience to evaluate management actions.
Yet even without full understanding of ecosystem functioning and how all the moving parts of ecological and social resilience fit together, we know enough to know what we should be avoiding. This isn't rocket science! Pressures that cause particularly significant negative impact need to be alleviated, whether these pressures originate in the target environment or well outside it.
In fact the best use of scientific understanding of socio-ecological resilience may be to help identify priorities. In a recent paper (see Mumby et al. in the above box "More sources on ecosystem resilience"), the authors present complicated notions of resilience, vulnerability, and robustness, tailored for effective management. In cases where there is a real danger of inhibited recovery from disturbance, they argue that using science to assess resilience helps avoid points of no return. But in systems that do not exhibit alternative stable states or clear thresholds, assessing vulnerability (a negative attribute) and robustness (a positive one) makes good use of science to identify the threats that need most urgent attention.
Do not stop with the low-hanging fruit
This issue of MEAM asks whether focusing attention on intact systems is preferable to focusing on degraded systems already in decline. While quick wins may be pragmatic, I would hope that we don't stop there, and that we use our science and understanding of what makes ecosystems and societies resilient to focus management attention where it is really needed. We can do that now, even with incomplete scientific understanding, especially if we tailor management so that it expressly generates useful information to fill the gaps.
In the vast mangrove complex that is Mexico's Marismas Nacionales, many questions about watershed and coastal hydrodynamics remain unanswered. But among the mosaic of pristine mangrove and saltmarsh, mixed with highly degraded lagoons and coasts, we can quickly identify which places provide - or could provide if restored - the most ecosystem services. These need to be priorities for management. And we already know what needs to be done to improve the health of the lagoons and prevent further mangrove die-back: ensure that adequate, good-quality water is delivered to the estuary, likewise ensure that appropriate sediments are delivered, reduce the dumping of feed into lagoon waters (meant to boost shrimp productivity), discourage ejidos (agricultural communities) from building earthen dams to irrigate, and redo some roads so that water circulation is improved. For the last, a targeted monitoring program could quickly fill gaps in hydrological understanding through low-tech, citizen science. No one would say the complicated situation in Marismas is a low-hanging fruit, but the management challenges are surmountable, especially if an integrated EBM approach is adopted.
Thus, instead of being seduced by the easy-to-pluck fruit, we should harness science to lower the fruit-laden branches that are tantalizingly out of reach. High-hanging fruits may present us with more of a challenge, and our attempts to practice good EBM may be rife with uncertainties, but we will never maximize resilience unless we point our attention to places and issues where management is needed most.