kevin.b.kenny at gmail.com
Wed Dec 18 22:22:43 UTC 2019
On Wed, Dec 18, 2019 at 2:08 PM Clifford Snow <clifford at snowandsnow.us> wrote:
> How should eelgrass be tagged? I see that wetland=reedbed  has been used in tidal areas mainly in Europe but also in the US but they are two different plants.
Perhaps wetland_class=emergent or wetland_class=aquatic_bed? (How does
the eelgrass grow in the area you're considering?)
Thus saith 'Classification of Wetlands and Deepwater Habitats of the
United States' (https://www.fws.gov/wetlands/documents/classwet/index.html):
Definition. The Emergent Wetland Class is characterized by erect,
rooted, herbaceous hydrophytes, excluding mosses and lichens. This
vegetation is present for most of the growing season in most years.
These wetlands are usually dominated by perennial plants. All water
regimes are included except subtidal and irregularly exposed.
Definition. The Class Aquatic Bed includes wetlands and deepwater
habitats dominated by plants that grow principally on or below the
surface of the water for most of the growing season in most years.
Water regimes include subtidal, irregularly exposed, regularly
flooded, permanently flooded, intermittently exposed, semipermanently
flooded, and seasonally flooded.
Aquatic beds further divide into algal (e.g., kelp, rockweed,
stoneword), moss (e.g. Fisseidens, Fontinalis), rooted vascular
(Zostera would fall in this category), and floating vascular
(duckweed, water lettuce, water hyacinth, water-nut (Trapa), water
fern (Salvinia), bladderwort, and so on).
Rooted vascular aquatic beds occur in marine, estuarine, riverine,
lacustrine and palustrine systems
Some species, such as the water lily Nuphar luteum, are hard to
classify between 'aquatic bed' and 'emergent', since it usually grows
as lily pads, but occasionally stands erect above the water surface.
Some of the eelgrasses have the same difficulty in classifying.
The categories are always going to be fuzzy around the edges.
USFWS would therefore label your eelgrass bed - if I understand
correctly what you're trying to label - as "Marine, subtidal, aquatic
bed, rooted vascular" while a typical reedbed might be "palustrine,
emergent wetland, persistent, dominant vegetation Phragmites spp." and
a typical alder meadow near me could be "palustrine, scrub-shrub
wetland, broad-leaved deciduous, predominant plant Alnus spp."
I have Absolutely No Idea how to fit a classification scheme like
Cowardin's into a 'folksonomy' like OSM's.
73 de ke9tv/2, Kevin
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