WETLANDS AS KEYSTONE ECOSYSTEMS: CONSERVATION CORNERSTONES IN DYNAMICALLY-CHANGING LANDSCAPES

摘要

Ecosystems are interconnected to each other in a web of patches, some of which may be more important regionally than others. These are as keystone ecosystems, ecosystems which have an impact on the landscape inordinate to their size or distribution. Keystone ecosystem evolved from the antecedent keystone species concept and the associated keystone processes model. While these concepts share similar characteristics as with keystone species, the keystone ecosystem concept requires refinement. Wetlands were first introduced as keystone ecosystems in Alberta by Locky (2011). In addition to functioning as distinct ecosystems unto themselves, wetlands are critical conduits between upland and aquatic ecosystems on a heterogenous landscape. Wetlands, like other keystone ecosystems, influence the landscape by two primary but not mutually exclusive pathways: shaping landscape disturbance regimes and providing limited resources on the landscape (DeMaynadier and Hunter 1994). They can survive fire and often remain unlogged, both cases equally providing reliable oases in seas of disturbance. Their resilience on the landscape places them in the role of conduits between different ecosystem types. Peatlands similarly modify and store carbon. Important facets of keystone wetlands as keystone ecosystems include values and societal benefits related to conservation, like carbon storage. However, it is clear that the strong functional linkages between wetlands and other landscape types suggest that negative consequences of wetland loss and impairment are exported far beyond geographic boundaries. Addressing wetland losses and conserving existing wetlands through policy provides value far and above the spatial extent on the landscape (Stoneman et al. 2016). When identified and mapped, keystone ecosystems can provide politicians, managers, planners, and the public useful information about critical ecosystem components (Stohlgren et al. 1997). Uniquely, this is where ecology and management become one. The planning process can be fortified with knowledge of keystone ecosystems. Conversion and or loss of critical functions and values can thus be avoided, particularly for long-term planning. In the case of Alberta, wetlands are found in all of the province's biomes and provide a wide range of ecosystem functions and properties. Wetlands have been subjected to a variety of anthropogenic impacts, including climate change (Locky 2011, 2012, Stoneman et al. 2016). Conservation and enhancement of wetlands leverages ecological and societal benefits far above the areal extent of the wetland and far beyond a wetland's borders.