Lesson 1.5 Pg.27- 36

Factors that Affect Wetlands and Watersheds Wetlands and Watersheds are controlled by interactions among chemical, physical, and biological factors These interactions are controlled in two ways Human interactions Natural events and processes

Human Activities More than half of the original 220 million acres of United States wetlands have been lost These wetlands were destroyed in a variety of ways due to human activities Mining - Waste disposal Agriculture - Mosquito control Urbanization - Industrial processes Construction - Draining

Effects of Agriculture Agricultural practice can disrupt or even destroy a wetland in different ways Examples: Wetlands are degraded when crops are harvested Drainage and Irrigation Ditches Inefficient irrigation leads to build up pesticides, pathogens, and nutrients Accumulation of these substances leads to degradation in water quality in the soil and groundwater

Effects of Agricultural Animals Animal wastes can contaminate wetlands Overgrazing can also damage wetlands Exposes soil to erosion by wind and water Increases the amount of sediment that reaches and often pollutes a wetland

Effects of Agricultural Pesticides and Fertilizers Pesticides and Fertilizers are the most harmful effects of agricultural on wetlands Contaminate wetlands by direct application in runoff, or by settling out of the air When these substances reach high enough levels they can: Kill wildlife Poison food sources Destroy the wetlands

Urbanization Urbanization is a major cause of Wetland Impairment – EPA Urbanization of the modern landscape of concrete and other materials increase the amount of runoff Runoff carries harmful substances that: Increases: turbidity and salinity Decreases: the amount of dissolved oxygen

Construction Construction of roads and bridges over wetlands increases the amount of sediment deposited in these ecosystems Paints, cleaners, salts, herbicides, dust-control substances, and other chemicals used along roads contribute to wetland damage Roads restrict the movement of species Leads to death of some species

Urbanization and Construction Canals, Ditches, and levees divert water away from its natural flow Increase the rate at which water flows into and out of the wetland Increased flow reduces the buffering ability of wetlands Increases turbidity Decreases aquatic plant life

Mining Mining operations can result in the loss of wetlands Phosphate Mining Eliminated thousands of acres of wetlands in Florida Peat Mining Peat = a form of organic matter that is used as fuel Vegetation is cleared from wetlands Wetlands are drained and roads are built so they can access the peat

Mining Rocks and Minerals Mining of rocks and minerals (Occurs in PA) Abandoned and active coal results in acid drainage Increases the pH of nearby wetlands Introduces heavy metals

Industry Construction of office buildings, factories, and processing plants can reduce the acreage of wetlands Work done in the industrial buildings damages the environment Water intake causes habitat fragmentation Release of water causes thermal pollution, which leads to algal blooms

Waste Disposal Waste is a by-product of urbanization Most urban waste is placed in landfills Landfills in the US are usually within 1 mile of wetlands Landfill leaks are extremely toxic to wetland organisms

Waste Disposal Sludge and wastewater treatment plant effluent are other major forms of waste Both are rich in nitrogen and phosphorus Causes algal blooms

Effects of Algal Blooms Excess algae prevents sunlight Reduces or entirely prevents photosynthesis Results in plant death Remove dissolved oxygen from the water , which kills many organism at the bottom of a wetland ecosystem

Complete the Following… Answer Review questions 1 and 2 on page 36 Hold on to them until you complete the rest of the review questions

Watershed Quality Human activities also affect watersheds Agencies are responsible for monitoring watersheds United States uses the Index of Watershed Indicators (IWI), to gather and assess data about aquatic resources Also used to determine whether human activities on the land within a watershed place them at risk

Condition Indicators IWI includes more than a dozen indicators One group of indicators reflect actual conditions in a watershed (Condition Indicators) 1. Presence of Contaminated Sediments Contaminated sediments can harm or even kill organisms Can also pose a risk to human who eat contaminated fish When indicators are high, fish consumption advisories are issued

Vulnerability Indicators IWI includes indicators that measure the vulnerability of a watershed Vulnerability Indicators show whether human activities produce negative effects on the watershed One vulnerability indicator measures the risk of extinction faced by various organisms If the indicator is high, measures are taken to protect the species at risk

Vulnerability Indicator Examples One vulnerability indicator measures the risk of extinction faced by various organisms If the indicator is high, measures are taken to protect the species at risk

Vulnerability Indicator Examples Another vulnerability indicator is human population growth Rapid increases in population growth can place stress on watersheds Need of freshwater and runoff produced by humans are important vulnerability indicators When both indicators are high Watersheds are at risk of becoming depleted or polluted

Vulnerability Indicator Examples Dams are another vulnerability Indicator Dams decrease water circulation Leads to increased temperatures Leads to decreased dissolved oxygen levels Leads to changes in salinity and pH If not corrected leads to deaths of many watershed organisms

Complete the Following On the same sheet of paper with the previous review questions Contrast the two types of IWI indicators Give two examples of each and explain how they affect watersheds