[Photo: Northern leopard frog (Lithobates pippins) an amphibian species that is state-endangered in Washington. Source: Douglas Wilhelm Harder. CC-BY-SA 3.0 in Creative Commons.]
What is a Wetland?
Let's begin this unit by making sure we understand something about how wetlands are defined and then begin to explore and appreciate the vast diversity of different kinds of freshwater wetland systems throughout the world. As you will quickly learn, all wetlands are not the same. The different types of wetlands greatly influences the types of restoration strategies that might need to be employed.
Let's start by seeing how a few different wetland organizations answer this question. As you look through how these two organizations answer the question of what is a wetland, you'll begin to see and appreciate the diversity of different wetland types and how important they are to many different species.
The Wetlands Initiative - What is a Wetland?
Wetlands International - What are Wetlands?
Next, let's look at some short video clips that introduce wetland habitats and the importance of wetlands:
Wildfowl & Wetlands Trust (WWT):
Oklahoma Gardening: Benefits of Wetlands
Liquidity: The Value of Wetlands DOCUMENTARY
Wetland Management & Conservation: Hawai'i's Endangered Endemic Waterbirds
In our study units on wetlands, we will use a wide variety of open-source technical materials from the WSU libraries, including free online textbooks.
To start our studies, go to PLOS, the open-source journal and download a pdf copy of "Underwood, J.J., M. Silbernagle, M. Nishimoto, K. Uyehara. 2013. Managing conservation reliant species: Hawai'i's endangered endemic waterbirds. PLOS ONE Vol. 8, Issue 6, e67872.
Download Link: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0067872
[Photo: Yellow-winged Darter (Sympetrum flaveolum). Source: Wikipedia. Author: "Sympetrum flaveolum - side (aka)" by André Karwath aka Aka - Own work. Licensed under CC BY-SA 2.5 via Creative Commons.]
Wetland Habitats of North America
While there are different wetland habitats all around the world, the diversity of wetlands in North America represents a large portion of the different types of wetlands one can find no matter where on this Earth you might travel. But before we begin a survey of wetland habitats, let's consider how wetlands are classified and grouped into categories for study of ecological characteristics, management, conservation, restoration, legal protection, etc.
How to Define a Wetland?
In the first part of this unit, we had a broad and simple overview of what constitutes a wetland and their considerable ecological and economic importance. There are many, and sometimes highly technical and legal definitions of wetlands, but initially for our purpose, we may consider the following simple definition:
"A wetland is an ecosystem that arises when inundation by water produces soils dominated by anaerobic processes and forces the biota, particularly rooted plants, to exhibit adaptations to tolerate flooding."
- (Paul Keddy 2000)
Wetland Classification
Now that we have a handy, short definition of wetlands, let's begin to consider the amazing diversity of wetland types by looking at a few selected examples. But first, one of the most important, influential, and widely cited classifications of wetlands is that of Cowardin et al. (1979). If you are interested in wetlands, I recommend that you download and retain a copy of this publication to build your own reference library of key wetland literature:
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Dept. Interior, Fish and Wildlife Service, Office of Biological Services. Washington, D.C.
In addition, to the full publication above, several useful summary charts and tools provide an excellent, broad overview of what is called the "The Cowardin System of Wetland Classification." See and download one such definition and classification chart.
Another important wetland classification publication that you might want to download and retain for your future use if you are interested in wetlands is one from the Environmental Protection Agency (EPA):
U.S. EPA. 2002. Methods of Evaluating Wetland Condition: Wetlands Classification. Office of Water, U.S. Environmental Protection Agency, Washington, D.C. EPA-822-R-02-017.
[Photo: Sphagnum moss and sedges in a floating bog mat along the shore of a lake. Source: Wikipedia. Author: "Drosera anglica habitat" by No machine readable author provided. NoahElhardt assumed (based on copyright claims). - No machine readable source provided. Own work assumed (based on copyright claims). Licensed under CC BY-SA 2.5 via Creative Commons]
National Wetland Inventory
The U.S. Fish and Wildlife Service maintains the National Wetland Inventory (NWI) to provide federal and state agencies and the public with information on the distribution and status of wetlands in the United States. This extensive resource is particularly valuable when agencies and organizations are concerned with wetland delineation and mapping. To communicate information about specific types and conditions of wetlands on maps, a series of wetland codes are used to classify wetlands by the USFWS.
Characteristics of Major Types of Wetlands
There are fundamental differences in the characteristics of wetlands depending on whether they are coastal or inland wetlands and whether they formed primarily by inputs of water from precipitation, groundwater, or surface flow. In addition, specific characteristics and ecological features of wetlands are created by differences in climate, geomorphology, soils, chemistry, and disturbance factors (e.g., fires, grazing, flooding).
Wetlands with Mostly Precipitation Inputs:
[Photo: Viru Bog in Lahemaa National Park, Estonia. Source: Wikipedia. Author: "EE-Lahemaa-Bagno Viru" by Lysy - Own work. Licensed under CC BY-SA 3.0 via the Creative Commons)
Bogs: are formed on acid peat deposits, frequently in the boreal forest regions of the world, although other types of bogs (see below) are found in other regions.
Wikipedia - bogs.
National Geographic (note: click on the series of images to see different wetlands) - bogs.
What is a Bog and Why Should We Conserve It?
Pocosins (from a Native American word meaning "swamp on a hill"): are evergreen shrub bogs found in the Atlantic coastal plain of North America, although the majority of pocosins are located in North Carolina.
Wikipedia - Poscosins.
Pocosin Restoration: Ancient Ecosystem, Future Conservation Landscape
Carolina Bays: are unique wetlands formed in elliptical depressions found in the Atlantic Coastal Plain all the way from Maryland to Florida.
But here's the really interesting thing about Carolina Bays (especially for those interested in geology and geomorphology), we don't know (or at least not everyone agrees) on how they were formed. Imagine that. Not having a definitive knowledge of how they were created. Amazing!
Wikipedia - Caroline Bay.
A Google Earth Tour of the Carolina Bays
Let's take an aerial tour of the Carolina Bays to get a good feeling for how amazing these wetlands are and the geographic location and extent of this landscape.
Cypress Domes: are a type of swamp, found in flatland depressions in the Gulf and Atlantic coastal plain, often characterized by the presence of pond cypress (Taxodium ascendens). States which contain cypress domes include Georgia, Florida, Alabama, Mississippi, and Louisiana.
Big Cypress Swamp: the Western Everglades
An Introduction to Wetland Scientific Literature
Now that we've had an introduction to some extremely interesting types of wetlands (only a brief sample), let's look at a journal that is useful in studies about wetland ecology, management, and restoration.
Published journal papers provide an excellent summary of the topic on which they are written, and usually in a highly condensed form. Moreover, as has been typical so far, my approach is to use most journal papers to convey primarily key concepts or ideas, without going into all the technical details of methodology (how a study was conducted; its statistics, etc.).
Rather, my approach is generally to have you read only selected portions of any given journal paper, usually just the abstract, introduction, and perhaps sometimes the conclusion.
These key portions of most journal papers are short, but contain the major punchlines of the study or report. That way, if I have you look at 2, 3 or even more papers in this way, the time commitment is greatly reduced.
I want you to grasp a series of key concepts about wetlands, rather than get bogged down (sorry, I couldn't resist the pun....) with plowing through too much text just to get to the punchline for the paper.
Okay, let's take a shot at this approach and show you what I mean by looking at a small sample of papers that illustrate some of the interesting features of the types of wetlands we're covering in this study unit.
Selected Short Reading & Study Assignments
(Wetlands is an online journal available through the WSU library. It's about the 4th publication listed if you do a search on "Wetlands" in SearchIT.)
(please read the abstract & introduction only of the following journal papers):
1) Richardson, C.J. 2003. Pocosins: Hydrologically isolated or integrated wetlands on the landscape? Wetlands 23(3):563-576.
2) Sharitz, R.R. 2003. Carolina Bay wetlands: unique habitats of the southeastern United States. Wetlands 23(3):550-562.
3) Casey, W.P. and K.C. Ewel. 2006. Patterns of succession in forested depressional wetlands in north Florida, USA. Wetlands 26(1):147-160.
4) Aldous, A.R., M.W. Gannett, M. Keith, and J. O'Connor. 2015. Geologic and geomorphic controls on the occurrence of fens in the Oregon Cascades and implications for vulnerability and conservation. Wetlands 35:757-767.
5) Bedford, B.L. and K.S. Godwin. 2003. Fens of the United States: distribution, characteristics, and scientific connection versus legal definition. Wetlands 23(3):608-629.
Study & Discussion Questions:
- Why does the PLOS ONE article on Hawai'i's endangered waterbirds illustrate some of the important benefits of wetland management?
- From the Pocosins journal paper: Why is the legal definition (ruling) of "isolated wetlands" versus the ecological reality causing such concern among wetland scientists and conservationists?
- From the Carolina Bay wetlands journal paper: What is the primary driver of the hydrology (annual water source) of Carolina Bay wetlands?
- From the article on succession in forested depression wetlands in Florida: Why is the basal area of the conifer, Pond cypress (Taxodium distichum) generally seem to be greater in medium-depth swamps?
- From the article on fens in the Oregon Cascades: Why are these fens particularly susceptible to the predicted impacts of climate change?
- From the article on fens of the United States: Why are fens so critical for biodiversity conservation? Also, how would you try to describe to the general public (in your own words) what the difference is between a bog and a fen?
Due Date: Tues. Dec. 1st
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