The same characteristics that made the Taiya and Skagway valleys attractive to Tlingit traders and gold rush stampeders also contribute to the ecological importance of the Klondike Gold Rush NHP area. Lynn Canal is a saltwater fjord that pierces deep into the heart of the coastal mountain range. The Taiya and Skagway valleys provide short pathways to glacier-free mountain passes connecting to the interior. Thus, the Klondike Gold Rush National Historical Park area is the northernmost, interior-most conduit for ecological exchange between the coastal rainforest ecosystem and the interior continental ecosystem. It has been an important avenue for plant and animal expansions in the past, and continues to be the site of species interchanges today.
Our valleys also exhibit environmental conditions that are unique to southeast Alaska. There are other passes to the south, but they all open onto coastal river valleys with typical rainy, temperate rainforest climates. Rainfall in the Juneau to Ketchikan area ranges from 90 to 160 inches per year. Even Haines, only 15 miles to the southwest of Skagway, has 60 inches of annual rainfall. Skagway experiences an average of only 26 inches of rain per year.
The low rainfall produces a special environment for plants and animals. It can get dry enough in the Taiya and Skagway valleys that forest fires occur, something unheard of throughout the rest of southeast Alaska. Plants and animals that expand from the interior into the Klondike Gold Rush National Historical Park valleys find conditions that with some characteristics of the temperate rainforest (but much less extreme than most of the southeast Alaska coastal rainforest), and with some characteristics of the drier, interior ecosystem.
Our geographic position combined with an environment unique in the southeastern Alaska rainforest, has led many ecologists to postulate the Klondike Gold Rush National Historical Park area as a biodiversity "hot spot". Certain animals more common to the interior, such as the pika and arctic ground squirrel, are known to occur in the Park valleys. Some botanists propose the head of the Lynn Canal, near Skagway, as the "greatest centre for plant diversity in Alaska" (Pojar & MacKinnon, 1994).
Biodiversity is an important natural resource at Klondike Gold Rush National Historical Park. The natural resources also include the Park's scenic, glacial valleys - and the geologic and environmental processes that are still at work molding the landscape. They include the plants and animals that use the valleys now, and those plants and animals that may naturally expand into the valleys in the future. They also include the natural progression of growth and decay, and the effects of these processes upon the remains of past human endeavors. Finally, they are the setting for people to experience the natural sounds, sights, smells and feel of a special coastal ecosystem.