Swamps, marshes, bogs, fens are all examples of wetlands that are important to our ecological system. They provide water, control floods, and are important to fisheries. Swamps are forested wetlands which are near large lakes and rivers. They have slow-moving waters and support woody plants, such as mangroves or cypress trees. Marshes on the other hand have the same water source but have softer, non-woody plants. Bogs are characterized by peats, left overs of dead plant material. Their water source is mainly from precipitation and no external runoff or river. The water in bogs has mostly a lower pH limiting survival of plants and animals as compared to marshes that have a neutral pH making them rich with plants and animals. Fens also have peat. They are high in nutrients and usually also pH neutrals. Fens near each other can form bogs.

Swamps are forested, marshes are populated by herbaceous plants. Bogs accumulate peat. Fens have neutral or alkaline water chemistry. The types can overlap.

Surprisingly, there are some subtle differences between these habitats. They are all considered wetland habitats as they are periodically inundated with freshwater.

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.

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.