Structure

Wetlands structure and the spatial distribution the land greatly affects which plants are found in each area of the wetland. Zonation is a process that is used to measure the changes in the environment of the wetlands, and tends to be measured by water depth (Keddy, 273). The different zones are separated mainly by the varying water levels which influences which plants can live in the area, and is a primary factor in influencing how the ecosystem develops. The process in which a wetland often develops and transitions into a progressively more terrestrial environment is through a process called Hydrarch Succession (Tiner, 34). 

The Hydrarch Succession is manifested through how each zone is developed around the water and how the different zones influence each other. At a smaller spatial scale, tidal freshwater marshes, like most types of wetlands, exhibit horizontal donation of vegetation along elevation/hydro period gradients. As in most marshes, tidal freshwater marsh vegetation is often divided into two zones, high marsh and low marsh (Swarth). When we visited Jug Bay, we saw many different zones, but we mainly studied open water, low marsh and high marsh. 

When we unloaded our canoes, we started in open water, where no above-water plants grow. One of our first stops was in the low marsh, which is the next stage of zonation in relation to water depth. In low marsh, species such as spatterdock and wild rice best survive. The root systems of these plants are completely submerged in water, but their leaves and buds grow above water. In the high marsh, more tall, grassy plants grow. In this zone grows low-land herbaceous vegetation. The high marsh is also able to sustain a higher variety of animal life.

At the end of our field trip we transitioned from marsh to swamp. One of the primary differences between the two is that trees grow in swamps. In low marshes, the plants are dependent on water and have adaptations that allow them to survive in water, whereas in swamps the plants have fewer limitations on how they grow. In the picture on the right is a part of Jug Bay that is a good example of a transition from marsh to swamp. The plants begin to heighten and there are fewer grassy plants.

Past the transition from marsh to swamp was this beautiful Riparian Swamp. The riparian zone are an area of land adjacent to a stream or river that is periodically influenced by fluctuations of water levels (Mitsch & Gosselink 1986). This area appears to be more of a typical river area in which there are a substantial amount of trees along each river bed and up into the surrounding woods. 

To learn more about the difference between marshes and swamps, read this article.

References: 

Keddy, Paul A. Wetland Ecology: Principles and Conservation. Cambridge, UK: Cambridge UP, 2000. Print.

Mitsch, William J., and James G. Gosselink. Wetlands. 3rd ed. New York: Van Nostrand Reinhold, 1993. Print.

Swarth, Chris. "Jug Bay Data." Jug Bay Wetlands Sanctuary News 26 (Summer 2012): n. pag. Print.

Tiner, Ralph W. In Search of Swampland: A Wetland Sourcebook and Field Guide. New Brunswick, NJ: Rutgers UP, 1998. Print.