DSE-SAWC collaboration Beginning in early 2020, Discovery Southeast is assisting the Southeast Alaska Watershed Coalition with investigations at Fish Creek…2020 | Richard Carstensen |
Vascular ‘halophytes,’ upper intertidal
‘Halophytes’ are salt tolerant plants (Not salt-loving plants,
halophiles, as the ecologist John Thilenius memorably insisted!) The community of vascular halophytes (as opposed to algae) in the upper intertidal is known as the salt marsh. It’s helpful to further subdivide the salt marsh into the high marsh, populated mostly by slightly tolerant grasses, and low marsh, dominated by more tolerant Lyngbye sedge.
The low marsh community of tidal sedges, goosetongue, and arrowgrass is the salad bowl of Southeast. In contrast, the high marsh is dominated by grasses like beach rye—more fibrous and less palatable than sedges—and this belt has generally lower wildlife value.
NWI (National Wetlands Inventory) maps do not delineate high and low marsh. This key ecological break needs more cartographic attention throughout Southeast Alaska. Only for the Mendenhall Wetlands near Juneau have the marsh differences been well-mapped (Carstensen et al 2004). Studies there show that the high marsh-low marsh break has changed dramatically during the past century. Human construction and river sedimentation are partially responsible, but the primary driver of salt-marsh community changes is glacial rebound. As glaciers and icefields melt, northern Southeast is responding by rising from the sea. The phenomenon, known as glacial or isostatic rebound, is more pronounced here than anywhere else in the world. Rebound rates in Glacier Bay and surroundings are as high as 1.23 inches per year (Larsen et al. 2005).
In spite of its confinement to a narrow intertidal belt, Lyngbye sedge may be the most important Southeast plant for many wide-ranging grazing birds and mammals. Its importance is especially significant in spring, before plants of the forest become available to herbivores. Sedges feed grazing black and brown bears, deer, moose, and several goose species.
For a salt-marsh food web and thoughts on trophic relations of this most generous of all ‘exporting communities,’ see Nature>Ecology>Trophics.
In this section
Fresh and saltwater wetlands serving birds Wet, open places shut down pretty firmly to feathered things in the Alaskan winter,…Spring 1999 | Richard Carstensen | 6 pages
In summer 2014, Koren Bosworth, Cathy Pohl, Andrew Allison and I surveyed wetlands throughout the CBJ. Although we were not…2016 | Richard Carstensen | 31 page excerpt (of 512p)
In late October, the meandery delta channels at Asx‘ée, twisted tree (Eagle River) are pretty ‘used-up.’ Salmon season is mostly…2015 | Richard Carstensen | 1 minute
In June, 2013, Diane Mayer of Southeast Alaska Land Trust asked Koren Bosworth and me to survey and describe wetlands…2013 | Richard Carstensen & Koren Bosworth | 64 pages, 12MB
Out to the scout campside of Eagle River today, Sept 10, 2017. This is where I became a naturalist in…2017 | Richard Carstensen | 2 minutes
In 2009, with support from the Southeast Alaska Land Trust, Bob, Mary, Marge and I distilled much of the information…2009 | Armstrong, Carstensen, Willson and Osborn | 82 pages
Discovery naturalists Steve Merli, John Hudson and Richard Carstensen walked from end Mendenhall Peninsula Road to Industrial Boulevard with staff…2018 | Richard Carstensen | 4:21 minutes
Trophics and geography Nexus explains how estuaries develop, their food webs, and their importance to the greater archipelago. Includes field…2004 | Richard Carstensen, Kathy Hocker | 12 pages
Summary of a 14 month bird survey on Mendenhall Wetlands State Game Refuge, undertaken on request from US Fish &…2004 | Robert Armstrong, Richard Carstensen, Mary Willson | 77 pages
Vegetation types, tidal elevations, property boundaries, and their relation to glacial rebound and the conservation of accreted land on Mendenhall…2004 | Richard Carstensen & Terry Schwartz | 18 pages