physical features and biotic features of our planet

Ecological describes the process of ecological communities changing over time in terms of species composition. In primary succession, the formation of new land or rock provides a habitual framework which overtime, evolves to support a larger variety of life. For example, upon volcanic eruption, the resulting stream of lava incinerates everything along its path creating a barren environment habitable by only a few ‘pioneer’ plant species. Yet the presence of these pioneer species can attract other living organisms and over time, the environment gradually becomes habitable once again. Secondary succession on the other hand, occurs when an existent ecosystem is disrupted and then later recolonized. For example, following a forest fire many plant and animal species may be lost. However, the removal of these species subsequently provides space for other plant and animals to ‘move in’ and ultimately progressively repopulate the area.
Sand dune communities are a classic example of ecological succession. The sand dunes of Lake Michigan were studied by Henry Chandler Cowles in 1899. He identified multiple different communities of plants that represented different stages of succession. The community closest to the lake on the windward side of the dune is the youngest, and the community farthest from the lake on the leeward side of the dune is the oldest. Although there are some nice sand dunes in Indiana and Michigan, Illinois only has one site left with pristine dune habitat—Illinois Beach State Park.
At Illinois Beach State Park, we will examine succession in the dune and swale complex that forms parallel to Lake Michigan. Sand is deposited by winds coming from the lake to form dunes, or ridges. In between parallel dune ridges, lowland swales occur. These swales often include wetland habitat and are home to species found in few other places. Older dunes are often wooded (have trees) and younger dunes usually have vegetation that is low in stature.
As we walk around the habitat, note the physical features and biotic features of each area. Include illustrations of the various parts of the habitat with informative labels.
1. On the beach, what are your impressions of the habitat? What physical characteristics are important here for plants or animals that want to live on the beach? Do you see any plant or animal life here?
2. On the foredunes (closest to the beach facing the lake), what physical characteristics are important? Which types of plant species and growth forms are present? One of the main plants found on foredunes is marram grass (Ammophila breviligulata). Do you see A. breviligulata on only the foredunes, or does it occur elsewhere?
3. Describe a swale. What are the physical features of the swale? Which types of plants are present (what growth forms do you see)?
4. As you examine the dune ridges, describe the types of vegetation. Do the dunes look similar, or are some dominated by different plant species than others? What explains the similarities or differences?
5. What evidence do you see of facilitation, tolerance or inhibition? Do you see any evidence of competition?
6. Before this trip, had you visited a sand dune system before? What are your impressions of the site and the ecosystem in general?

Calculate your paper price
Pages (550 words)
Approximate price: -