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.

Black bear trails in low-marsh sedges, Kòonax, (Traitor’s Cove, Revillagigedo Island).

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.

Mud Bay (no Tlingit name?). In June, 2013, Discovery Southeast & Bosworth Botanical Consulting surveyed this estuary for the Southeast Alaska Land Trust. Our report is here. View is south down spine of Ayik, you gotta get ready (Chilkat Peninsula). Jilkáat Wát, cache-river mouth (Chilkat estuary) in right distance.

In this section

Fish Creek studies

DSE-SAWC collaboration Beginning in early 2020, Discovery Southeast is assisting the Southeast Alaska Watershed Coalition with investigations at Fish Creek…

2020 | Richard Carstensen |

1999 Spring newsletter: Birds and wet places

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

Supplement to the CBJ wetlands surveys, 2016

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)

Flight at Asx’ée, twisted tree (Eagle River)

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

Mud Bay survey for SEAL Trust

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

Eagle beach aerials

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

The Mendenhall Wetlands: a globally recognized Important Bird Area.

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

Teacher walk, Wigeon Ponds, West Refuge

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

2004 fall newsletter. Nexus: estuaries of Southeast Alaska

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

Hotspots: bird survey of Mendenhall Wetlands (April 2002 to May 2003)

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

Glacial rebound in the Mendenhall Wetlands

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