June 1 – 5, 2020 Disturbances in Ecosystems Disturbance – a temporary change in environmental conditions that causes a pronounced change in an ecosystem Usually ecosystems are relatively constant under stable conditions A change in one or more biotic or abiotic factors can cause change Natural disturbances: damage or destruction caused by nature Tornadoes Volcanoes Forest fires Human-Caused disturbances: damage or destruction caused by humans Human Caused Disturbances Invasive Species Human population impacts the environment in many ways Greenhouse Effect and Carbon Footprint Pollution and Biomagnification Habitat Destruction The “Overs” Invasive Species Are species that are not native and whose introduction causes harm, or is likely to cause harm to the economy, environment or human health a plant, fungus, or animal species that is not native to a specific location and does not have a natural predator (an introduced species) tends to spread and can cause damage to the environment, human economy or human health Examples: Cane Toad Burmese Python Global warming aka Climate change Is the observed century-scale rise in the average temperature of the Earth's climate system, and its related effects. Occurs when CO2, fossil fuels, and other air pollutants get trapped in the atmosphere because of the greenhouse effect Effects of global warming result in: Rising sea levels Disruption of habitats Ozone depletion Greenhouse effect The greenhouse effect is a natural process that warms the Earth’s surface When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected to space and the rest is absorbed and re-radiated by greenhouse gases The carbon cycle adds to it Air Pollutants Anything added to the environment that has a negative effect on the environment or its organisms is called pollutants. Can take the form of chemicals, particulates, or microorganisms. The most common one is air pollutants. Water Pollution Rain can wash oil, pesticides, and fertilizers into storm drains Feedlots can discharge high volumes of waste, which flow into large bodies of water Industries can discharge waste with heavy metals, drugs, hormones, and other chemicals into bodies of water. Acid rain is a broad term that includes any form of precipitation with acidic components. These chemicals come from volcanoes, and the burning of fossil fuels (cars, electricity, manufacturing plants) Biomagnification Biomagnification refers to the amount of pollutants getting larger as they move from one trophic level to the next These chemicals don’t get broken down easily, so they build up Examples: Mercury in fish and Little fish eat polluted plants. DDT (pesticide) -tiny amount of chemical Medium fish eat the bigger fish. -tiny amount becomes a medium amount Big fish eat the medium fish. -medium amount becomes BIG!! Habitat Destruction Desertification Deforestation This process makes the land dry Deforestation is the clearing or becoming more desert-like over thinning of forests by humans time Drought, poor farming techniques, and deforestation can cause desertification Agriculture Industry Economic production and consumption Recreation It’s all about the “Overs” Overharvesting occurs when individual organisms are removed from an ecosystem faster than a population can replace them. Overfishing and overhunting will cause a decrease in genetic diversity or worse causing a species to go extinct. Ecological Succession Succession – the process of gradual, natural change and species replacement that takes place in the communities of an ecosystem over time Sequence of biotic changes that restores a damaged or uninhabited area Primary succession – the development of plant and animal life in an area that was previously uninhabited; no soil Secondary succession – the sequence of changes that take place after a community is disrupted by natural disasters or human actions Pioneer Species: Lichen and Moss Pioneer species – the first species to live in a new environment Initiate recovery following disturbance in both primary AND secondary successions Pioneers "pave the way" for later colonists by altering the biotic and abiotic environment: Primary vs. Secondary Primary Secondary NO SOIL or organic material YES SOIL; much faster than primary Only mineral material because soil does not need to be made sand, bare rock, bedrock from glacial Pioneers species are seeds or grasses outwash, volcanic ash and lava, flood and small plants remaining in the soil causing soil erosion, floods and or from seeds carried in by wind or tsunamis that add salt to environment animals from surrounding or soil erosion, landslide communities Lichens (fungi) and mosses are usually pioneer species that make soil Primary Succession Secondary Succession Results of Succession Pioneer community all the living organisms (usually just a few species, or even just one) that occupy an area undergoing primary succession in the beginning stages. Climax Community relatively stable, long- lasting community that is the result of succession .