Ecosystem Structure Function and Change

Ecosystem structure, function, and change

Royce Hatlevig

SCI/256  

12/14/2015

Dianna Gielstra

        The Rock River is one of the largest eco systems in my area that is managed for native species. The river is 285 miles Long and is home to over 400 species of wildlife most of which includes twenty percent of Americas duck population and forty percent of the migrating birds (Riveraction.org). The Rock River watershed originates in Horicon Marsh, Wisconsin, and joins the Mississippi at Rock Island. Land use in the majority of the watershed is either livestock operations or crop production. Due to the farming and livestock there is a abundance of nitrates increasing exponentially leading to adverse effects on wildlife and vegetation. The Rock River is typical for this type of ecosystem and is categorized as a large, low velocity, warm water river.

        The Rock River’s eco system has had many of its natural processes affected by humans over the years. These systems include water, nitrogen, carbon, and phosphorus cycling. They have changed more rapidly in recent years than in any time in our history. Human modifications of the River’s ecosystem have changed not only the structure of the systems, such as what habitats or species currently present, but also its processes and functions are being altered as well. Water withdrawals from the river for irrigation and industrial use have increased drastically over the years. The concentration of carbon dioxide and nitrogen has increased as well and most of that has taken place over the last 50 years. The effect of changes in the terrestrial portion of the rivers ecosystem has had a negative effect on the carbon cycle. Factors contributing to the growth of carbon dioxide saturation in the Rock River include afforestation, reforestation, and forest management as well as changes in agriculture practices; and the fertilizing effects of nitrogen deposition and increasing atmospheric CO2. 

The clearing of forests to produce farmland has led to on-going erosion in the Rock River with large quantities of sediment deposited into the water. Agricultural increases along with excessive use of nitrogen rich fertilizers have resulted in chemical loss to nearby streams and rivers. Elevated nutrient concentrations such as phosphorus can result in the eutrophication of slow-moving waterways and kills algae and other vegetation below the water which also leads to reduced oxygen levels which can kill off fish and other marine life forms.