Alaska Connections

Diane and I recently made a twelve day trip to Alaska with a group of birders from North Carolina and Virginia.  On this trip we would revisit places from our expedition of 31 years ago and go to some new ones.  We saw lots of new land- and seascapes, a Canada lynx and a walrus, a Gyrfalcon and Bristle-thighed Curlews.  We also ran into some plants and plant-ish things I have written about recently in this blog.

Last month I wrote about alders growing near my home.  In Alaska, at Summit Lake on the Kenai Peninsula, the alders were in flower.  Alders in North Carolina flowered in early March but in southern Alaska, June is the flowering season.   The alder we saw in at Summit Lake was Alnus viridis ssp sinuata, the Sitka alder.  This alder is a scrubby tree and grows throughout Alaska, across the Bering Strait into East Asia, along the west coast of North American into northern California and down to the northern Rocky Mountains. The Sitka alder’s leaves are bright green with serrated margins.  The female catkins were green and the male catkins were brown, had already released their pollen but were still on the plant.  Sitka alder is an early colonizer of new land, beginning primary succession.  With global climate change, glaciers are receding at an increased rate.  When the retreating glaciers leave exposed ground, Sitka alders become established.  Their nitrogen-fixing, symbiotic bacteria enrich the soil paving the way for new forest to grow where the glaciers disappeared. 

Sitka alder (Alnus virdis ssp. sinuata)
with catkins of male flowers.

Sitka alder (Alnus viridis ssp. sinuata)
with female catkins

Haircap moss (Polytrichum strictum) gametophytes

The moist forests on the south side of the Alaska Range support a wide variety of mosses.  I wrote about North Carolina mosses  in April.  In Denali State Park we found thick and beautiful stands of Polytrichum strictum, the haircap moss.  This moss has a circumpolar distribution and extends into the lower 48 US states.  Clusters of gametophyte plants produce a green, star-pattern.  The sporophytes, the result of moss sex, have a little hairy cap at their tops, covering the capsule where the spores are waiting to be released. 

Haircap moss (Polytrichum stgrictum) gametophyes
with sporophytes

Kamchatka rhododendron (Rhododendron camtschaticum)
flowering on the tundra

Back in January I posted about lichens in Florida and North Carolina.  Out on the tundra of Denali National Park, where willows are inches tall and tiny rhododendrons (Rhododendron camtschaticum) produce large flowers, we found several species of lichens including the famous reindeer moss.  Reindeer moss is, of course, not a moss but a lichen, that symbiotic organism made of a fungus and an alga.  The lichens pictured here are Cladonia rangiferina (gray reindeer moss) and Cladonia fimbriata (trumpet lichen).  Lichens form much of the diet of caribou, Rangifer tarandus who endlessly graze as they walk the tundra.  Caribou are the same species as the old-world reindeer but have never been domesticated.  These large herbivores can find lichens even in winter.  Caribou use their sharp hooves to expose the lichens below the snow.  Unfortunately we did not see any caribou grazing the lichens of the tundra.   

Reindeer moss, the lichen
Cladonia rangiferina

 

Trumpet lichen Cladonia fimbrata

The differences between the Southeastern US and Alaska are striking.  There is a transition from subtropical to arctic with different habitats, climates, plants and animals. These areas are separated by a distance of more than 3000 miles and 30 degrees of latitude.  But the similarities between the Southeast and Alaska are profound.  Linked by biogeography and the evolutionary history of the inhabitants, the similarities were as striking as the differences.