Jim Shives

Image of Arnica

One of the great joys of discovering the botany of Denali and Alaska’s other large natural areas is the intact nature of the plant communities that exist here. The distribution and abundance of the species that you will see in these landscapes is the result of the natural processes of birth, growth, and dispersal of our native species and their symbionts, parasites, predators, and competitors. This rich and intact tapestry woven by the multitude of interactions of species with their environments over geological spans of time is rare indeed on the face of our planet today. The flora and vegetation of even the largest wilderness parks of the continental United States, for example, are in fact very different from their condition even just 150 years ago. Many of the plant communities in those areas are today entirely dominated by non-native species that were introduced from Europe and other parts of the Mediterranean basin. Fortunately this is not the case here in Alaska, where the relative scarcity of roads and other developed land has limited these outside invaders to only relatively small and tenuous footholds around human settlements. At present, no exotic species are known to occur in intact native plant communities in our region of Alaska. Intact natural plant communities are an extremely precious resource, and unfortunately are becoming increasingly scarce on the face of our planet today. This is why it is so important that we continue to protect the natural landscapes that still exist in Alaska’s great wild lands.

Alaska stands at a floristic crossroads between Asia and North America. During the past two million years, this area has been predominantly associated with the biota of northeastern Asia as opposed to that of North America. This is because the periodic formation of continental ice sheets thousands of feet thick (which covered most of Canada and parts of the northern continental U.S.), has separated Alaska from continental North America on many occasions during this period of time. At the same time, the exposure of the Bering Land Bridge allowed plants and animals a wide dispersal corridor into Alaska from northern Asia. For this reason, many of the plant species of Denali occur in Alaska and northern Asia, but not elsewhere in North America. These plants are known as Beringian endemic species – species that occur only within the large region that was free of ice during the Pleistocene glacial advances.