Adaptation Measures

introduced exotic species may make it impossible for species to migrate to suitable areas in

response to climatic shifts.  Failure to include these stressors in any evaluation of potential

adaptation strategies will result in an incorrect picture of future ecosystem distributions.

CASE STUDY

Multiple Stresses on Great Lakes Rivers

Over the years, Great Lakes rivers have been subjected to numerous stresses.  For example, the

logging era resulted in cleared land, which led to warmer streams and increased sedimentation, which

was further exacerbated by floating the logs to river mouths.  Today, Grayling, Michigan, is a popular

recreational destination, but its namesake, a salmonid fish much sought after by fly-fishers in Alaska

and Canada, was extirpated in the 1990s.  Other types of fish habitat destruction, invasions of non-

native species, and chemical pollution are amongst the most important current stresses.  Agriculture

and sprawl are common examples of how changing land use and population can influence the delivery

of sediment, nutrients, and contaminants into surface waters.  Climate change will add yet another

stress.  Unless strategies focused on adapting to climate change also consider other significant

stresses, the adaptive responses may prove ineffective and fail.

Humans may also indirectly affect ecosystem migration through other activities, such as through

the consumption of water that is needed by the ecosystem to survive.  Competition for water in

the Great Lakes region is already a real concern, and is likely to increase with climate change.

Consider that as the climate changes, water supplies will be directly affected by precipitation

changes and increased evapotranspiration.  The availability of water also will be indirectly

affected by changes in the competition for water among multiple uses (e.g. urban water demand,

recreational activities, irrigation in agriculture, hydropower).  In such cases, the water required

by natural ecosystems such as wetlands and forests to survive may become scarcer.

A complete assessment of the vulnerability of Great Lakes systems to climate change and

potential adaptation strategies must consider the multiple stressors on the affected systems.  

Assessments that do not include these stressors will provide incorrect information to those who

are developing adaptive responses in anticipation of future change, increasing the possibility

that less effective adaptation, and in some cases maladaptive strategies, will be chosen.

By placing climate change in the context of multiple stressors, one opens up opportunities to

reduce vulnerabilities to other environmental stresses as climate change is addressed, and vice

versa (IPCC, 2002: 132).  For example, removing societal stresses and managing resources in a

sustainable manner may help unique and threatened systems also to cope with the additional

stress posed by climate change.  Addressing or avoiding land degradation also decreases

vulnerability to climate change, especially when response strategies consider the social and

economic factors defining the land-use practices together with the additional risks imposed by

climate change.  Problems with the availability, abundance, and pollution of freshwater, which

are often caused by demographic and development pressures, can be exacerbated by climate

change.  Reducing vulnerability to water stress (e.g. by water conservation, water-demand

management, and more efficient water use) also reduces vulnerability to additional stress by

climate change.

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