Leopold Center for Sustainable Agriculture

Interim Director: Sustainability and Resilience

Back to Leopold Letter Fall 2010

By LOIS WRIGHT MORTON, Interim director

Many of us have spent the summer scanning the Iowa skies, emptying our rain gauges and checking online weather radar. Painful memories of 2008 and August 2010 flooding have us re-evaluating this year’s land management decisions to prepare for next year’s risks and uncertainties. Eugene Takle, ISU professor of climate science, predicts wetter springs, drier autumns, more variability of summer precipitation with more intense rain events, an increase in humidity and, on average in Iowa, about five more frost-free days than in 1950.

Regardless of where you stand on the public debate about whether climate change is human induced, a natural cycle or some combination, there is scientific consensus that the natural variability of climate is significantly departing from our past experiences (Takle 2010; Milly 2009). The world we live in is dynamic and constantly changing. We see natural variability around us. Many of these changes we expect because of past experience. We expect that the Leopard frogs will call to each other in spring pools; the corn seeds will germinate and grow into straight tall stalks, ears bursting with yellow kernels; and our children will grow up to become adults.

However, some changes surprise us and we are unprepared for their impacts.

We are unprepared for a number of reasons. The change may be outside our current knowledge and past experiences. Change may have come slowly, creeping up on us so that we do not notice its evidence. We may have seen the changes but were too busy with other things in our lives and did not stop to consider future effects. Other times our science is incomplete. We have not discovered the patterns, trends or mechanisms that could predict change and prepare us for risks and uncertainties associated with change.

Rapid change is visible. A river overflows into an urban floodplain, submerging buildings and bringing soil washed from cultivated fields upstream. We are not as good at recognizing slow, less visible changes. Eastern redcedar encroachment on grasslands can amaze us by how quickly it dominates a landscape in a few short years, turning productive grassland into woody expanses. A decrease in natural forest patches in agricultural landscapes can lead to gradual habitat fragmentation, reducing the resilience of some bird and butterfly species that require tree habitats (Scheffer 2009).

Changes in water quality also can catch us unprepared. An overload of phosphorus and nitrogen nutrients in a shallow lake stimulates growth of microscopic vegetation called phytoplankton, turning the water greenish with a corresponding loss of clarity (Scheffer 2009). Vegetation feeding on nutrients can reduce turbidity (or cloudiness) and return lake clarity. However, at some point there can be too many nutrients for lake vegetation to get sufficient light and so it loses its capacity to clean the lake and disappears. The cloudiness returns, creating a new, hostile environment for fish and animals that require clear water to survive. Once nutrient levels exceed some threshold, it is not an easy process to reverse, as those who live in Shagawa Lake, Minnesota can attest (Carpenter 2003).

Changing weather patterns, Eastern redcedar encroachment, habitat fragmentation, soil erosion, and water quality are only a few of the serious resource management issues that threaten sustainability in Iowa. The “key to sustainability lies in enhancing the resilience of social-ecological systems, not in optimizing isolated components of the systems” (Walker and Salt 2006). Thus, it is critical that we not focus on one aspect of production or the environment, but learn to view our landscape as multiple, linked systems.

Our challenge is to better understand interactions among humans and nature, to recognize when they are vulnerable and in danger of losing resilience. Resilience is the ability of a system to absorb a disturbance and yet retain its structure and function (Walker and Salt 2006; Scheffer 2009). Gradual changes can reduce resilience and put the system at risk from small disruptions. We need to learn more about what makes a system fragile to the point that even a minor disturbance can trigger drastic change (Scheffer 2009). Resilience and sustainability are intimately linked. Managing our natural resource base and achieving sustainability requires understanding the resilience of the systems involved (Walker and Salt 2006).

The Leopold Center’s mandate from the Iowa Legislature is to build the science of sustainability in our agricultural landscapes and to communicate that science so that Iowans can make good decisions under uncertain and changing conditions. The Leopold Center exists because of the bold foresight of Iowa leaders who recognized that gradual and abrupt changes in agriculture have significant impacts on Iowa’s valuable natural resource base. They realized we need to know much more about interrelationships among agricultural systems, our rivers and lakes, soils, air, communities and economic health. They defined “sustainable agriculture” as “the appropriate use of crop and livestock systems and agricultural inputs supporting those activities which maintain economic and social viability while preserving the high productivity and quality of Iowa’s land.”

“Sustainability” and “resilience” are our goals. In the coming year the Leopold Center will focus on measuring sustainability and resilience and supporting projects that have potential to give Iowa more resilience and sustainability. The more we learn together about the processes and mechanisms of our social-ecological systems, the greater our capacity to change our policies and behaviors to adapt to, mitigate, and manage our agricultural landscapes and the natural resource base on which they depend.

Watch for guest columns in upcoming newsletters and on our website as we explore the meaning of sustainability and resilience, and how we can transfer what we learn to farmers, landowners and citizens of Iowa.

We are planning a Measuring Sustainability and Resilience workshop on May 25, 2011 for Iowa colleges, universities, private nonprofit agencies and foundations that are eligible to apply for the competitive grants we sponsor annually. These are our partners who are helping us build knowledge and work together on behalf of our precious Iowa landscape. – Lois

References

Carpenter, S.R. 2003. Regime Shifts in Lake Ecosystems. Ecology Institute, Oldendorf/Luhe, Germany

Milly, P.C. D., J. Betancourt, M. Falkenmark, R. M. Hirsch, Z. W. Kundzewicz, D. P. Lettenmaier, and R. J. Stouffer. 2009. Stationary is dead: Whither water management? Science 319, 573-574.

Scheffer, M. 2009. Critical Transitions in Nature and Society. Princeton University Press: Princeton, NJ.

Takle, E. S. August 13, 2010. Assessment of potential impacts of climate changes on Iowa using current trends and future projections.

Walker, B and D. Salt. 2006. Resilience Thinking: Sustaining Ecosystems and People in a Changing World. Island Press: Washington, DC.

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