再看看濕地的分類
這裡提到：
Bogs - These are wetlands that have a hard sealed clay soil bottom that prevents water from seeping out. Water collects in bogs (sometimes just from precipitation) and sticks around. These habitats are anoxic and dominated by sphagnum mosses and shrubs.
Fens - these are groundwater fed wetlands where a breach in a hard clay pan allows groundwater to seep up into the depression and form a wetland habitat.
Swamps - generally have slow-moving water and reside adjacent to rivers or other moving bodies of water. The level of water in a swamp can vary considerably with the adjacent river.
Marsh - Also a wetland that is adjacent to a moving body of water, but tends to not have much water movement. It also forms a transition between open bodies of water and dry land.
這裡又提到：
Bog: Acidic, low nutrient, peat rich areas that may contain trees. The only water source is from precipitation and snowmelt. The main plants are peat mosses and shrubs.
Fen: Peat rich areas that receive nutrients from the water that flows through them (surface runoff, groundwater). Typically flooded in the winter and dominated by mosses, sedges, rushes, and shrubs. Streams and/or pools may be present.
Swamp: Treed wetlands with stagnant or slow-flowing pools.
Marsh: Periodically or permanently flooded wetlands with changing water levels. The main plants are rushes, reeds, grasses, sedges and shrubs.
Shallow Water: Transitional areas between bogs, fens, swamps, marshes and permanent water bodies such as lakes. Include basins, pools, ponds, and channels.
而這裡說：
Bog / Fen: may or may not have trees; waterlogged soil with lots of peat; low productivity
- Bogs - fed by precipitation
- Fens - Fed by groundwater & surface runoff
Swamps: have trees like bald cypress; high productivity
Marshes: no trees; tall grasses; high productivity
這裡如此說明：
Organic Soil Wetlands:
Generally these wetlands are referred to as "peatlands" in recognition of their common ability to form peat (organic soil produced by the accumulation of plant material). There are two major types of peatlands – bogs and fens, both of which occur in similar climatic and geographic regions.
Bog – a type of wetland ecosystem characterized by wet, spongy, poorly drained peaty soil, dominated by the growth of bog mosses, Sphagnum, and heaths, particularly Chamaedaphne. Bogs are usually acid areas, frequently surrounding a body of open water. Bogs receive water exclusively from rainfall.
Fen – a type of wetland ecosystem characterized by peaty soil, dominated by grasslike plants, grasses, sedges, and reeds. Fens are alkaline rather than acid areas, receiving water mostly from surface and groundwater sources.
Mineral Soil Wetlands:
Marsh – a type of wetland ecosystem characterized by poorly drained mineral soils and by plant life dominated by grasses. Marshes are common at the mouths of rivers, especially where extensive deltas have been built. The marsh plants slow down the flow of water and allow for the nutrient enriched sediments to be deposited, thus providing conditions for the further development of the marsh.
Swamp – a wetland ecosystem characterized by mineral soils with poor drainage and by plant life dominated by trees. Swamps are found throughout the world, most often in low-lying regions (with poor drainage) next to rivers, which supply the swamp with water. Some swamps develop from marshes that slowly fill in, allowing trees and woody shrubs to grow.
The dominant vegetation, therefore, distinguishes the two major types of mineral soil wetlands: grasses dominate marshes, while trees dominate swamps. Both marshes and swamps may be freshwater or saltwater.
它之後的說明也很有意思，說明其他濕地分類法的來源：
Unfortunately, the "traditional terminology" has the significant disadvantage of being based on the traditional concept of a wetland. As such, it takes into account comparatively few wetlands, mostly of inland freshwater character and of a relatively narrow climatic zone. Another great disadvantage of these traditional names is that many of them are highly localized – for example, Johnson outlines that a "heath" in New Hampshire or Maine might be referred to as a "spong" in New Jersey (Johnson, 1985, in Johannesen and Gurganus), and Aber (2003) notes that the term "mire" is used mainly in Europe to denote any peat–forming wetland (either bog or fen). To avoid these disadvantages, attempts have been made to develop a classification system that would take into consideration the various wetland types all over the world.
Two main scientifically-based and in a way comprehensive wetlands classification systems, developed for the purpose of wetlands inventory and management, have gained broad acknowledgement nowadays: the first of them has been developed by Cowardin and co-workers for the needs of the US government, and the second has been adopted by the Convention on Wetlands:
1. The system developed by Cowardin and co-workers is organized in a hierarchical structure. In tribute to the "traditional terminology", in their system they distinguish between "wetlands" and "deepwater habitats", because "traditionally the term wetland has not included deep permanent water" (Cowardin et al, 1979). Nevertheless, the scientists recognize the importance of the holistic approach to classification of wetlands, therefore in their classification they have included both types. The classification system developed by the team defines five main Systems (Marine 海洋, Estuarine 河口, Riverine 河岸, Lacustrine 湖泊, and Palustrine 不連接其他湖泊河水的淺淡水沼澤), which are further divided into smaller Subsystems, Classes, Subclasses, and Dominance Types. As initially developed, the classification system set up by Cowardin and co-workers (1979) did not include many wetland types that have resulted from human activities.
2. To avoid the weak point of Cowardin et all’s classification system, the Convention on Wetlands developed a new and more comprehensive wetland classification system (adopted in 1990 and modified in 1996) – the Ramsar Classification System for Wetland Type.
更多連結：
Wetland Classification Systems
Wetland (湿原)
How Wetlands Work: Types of Wetlands
Wetlands Classification and Types
Types of Wetlands
Classification of Wetlands and Deepwater Habitats of the United States
WETLAND RESTORATION. A HANDBOOK FOR NEW ZEALAND FRESHWATER SYSTEMS
WETLAND TYPES
Wikipedia - Cowardin classification system
本文連結