Juneau Nature

Natural & cultural history of Juneau & Southeast Alaska

Juneau Nature - Natural & cultural history of Juneau & Southeast Alaska

Stillwater

Habitat in and beside lakes & ponds

Beaver ponds and stillwater sloughs on the delta at the head of Windfall Lake, north of Juneau.

Beaver ponds and stillwater sloughs on the delta at the head of Windfall Lake, north of Juneau.

In 2002, Discovery Southeast began a 2-year study of amphibian habitat, principally within half a mile of the Juneau road system, but in following years branching out to other parts of northern Southeast Alaska. We (Armstrong, Willson and Carstensen) soon noticed that toad, frog and newt stillwater breeding habitat could almost be considered the inverse of aquatic habitats selected by anadromous fish.

In consequence, while moving waters important to the Southeast ‘money-fish’ (salmon and trout) have been intensively researched for more than a century, the quiet spawning ponds of inedible (even toxic!) herps are almost completely unstudied, and even unclassified.

For our study, a geomorphic classification seemed most appropriate. In other words, what are the geological and biological agents of pond formation. Here they are, listed roughly in order from most recent (and rapidly changing) to most ancient (and successionally stable):
human – anthropogenic

beaver – created and actively maintained by beaver

glacial – kettles, etc uncovered since peak of Little Ice Age

uplift – ponds on former tideland developed since Little Ice Age

fen – ponds on gently sloping sedge/herb dominated peatlands

bog – ponds in sphagnum-dominated peatlands

bedrock – controlled by bedrock, includes larger lakes

Lakes and ponds are well mapped throughout Southeast Alaska in the Forest Service database. This allows GIS (Geographic information Systems) exercises on a regional scale. Density of larger lakes(left) and smaller ponds (right) is indicated by progressively darker color tones.

Lakes and ponds are well mapped throughout Southeast Alaska in the Forest Service database. This allows GIS (Geographic information Systems) exercises on a regional scale. Density of larger lakes(left) and smaller ponds (right) is indicated by progressively darker color tones.