Changes Over Time

Change is ever-present here in Denali National Park. Over thousands of years, the landscape has continually been shaped and altered.  Although plants often form the texture of the landscapes we inhabit, they are not guaranteed to persist unchallenged.

repeat photography toklat river: 1928, 2015Natural disturbances, both expected and unexpected can drastically alter a plant community at any time.  Successional cycles are at work in many communities as their species composition progresses along a presumed path.  Sometimes the path has an unexpected endpoint, and directional change occurs. Up until now these were the only forces at play but now, the greatest factor of change is being caused by humans.  Climate change has major effects on plant life and plant communities, thereby altering wildlife habitat throughout the subarctic.  Get a bird’s-eye view on Denali’s changing landscape by exploring the repeat photo collection.

2002 - 2007: Eolian Lowlands near Lake Minchumina AreaFires are a common natural disturbances in Denali’s boreal forest.  They have long been a part of the successional cycle and can provide many benefits to the park ecosystems.  Many abundant species in the boreal forest, such as black spruce (Picea mariana), have developed special adaptations to it.  There are however, limitations to these adaptations and it is uncertain how native plants will respond to the additional stress caused by climate change.

Human activity through direct land use and indirectly through modification of Earth’s climate system are rapidly changing Denali National Park’s landscape.  Some of these impacts have already been identified in repeat photo pairs taken within the park.  As a result of changes in vegetation there is potential for the tree line to continue moving farther north, widespread loss of habitat diversity and distribution, invasion of open wetland areas by woody vegetation, an increase in fires due to excess drying of woody material, shrinking ponds, successful proliferation of invasive species, permafrost melting, and glacial retreating, thinning, and stagnating.

Scientists are carefully tracking changes in landscape patterns by comparing photo pairs of the landscape. The changes thus far appear directional, representing a qualitative shift in the landscape composition, rather than a shift in vegetation due to succession or cyclical fluctuations.

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