Conservation Biology & Global Change Chapter 56

YOU MUST KNOW The value of biodiversity and the major human threats to it How human actions are changing the Earth How to predict consequences on both local and global ecosystems of specific human activities

Overview 1.8 million species have been named and described Biologists estimate 10–200 million species exist on Earth Tropical forests contain some of the greatest concentrations of species and are being destroyed at an alarming rate Humans are rapidly pushing many species toward extinction

Biodiversity A. Considered on 3 main levels – genetic diversity, species diversity, ecosystem diversity

B. 4 major threats – habitat loss, introduced species, over- B. 4 major threats – habitat loss, introduced species, over- harvesting, and global change

Population Conservation Minimum viable population (MVP) – results in loss of genetic variation and increases risk of genetic drift (disappearance of genes from the gene pool by random chance)

2. Extinction vortex - process that declining populations undergo when a mutual reinforcement occurs among biotic and abiotic processes that drives population size downward to extinction

Globally, 12% of birds, 20% of mammals, and 32% of amphibians are threatened with extinction An endangered species is “in danger of becoming extinct throughout all or a significant portion of its range” A threatened species is likely to become endangered in the foreseeable future

Benefits of Species and Genetic Diversity In the United States, 25% of prescriptions contain substances originally derived from plants For example, the rosy periwinkle contains alkaloids that inhibit cancer growth

Landscape and biodiversity 1. Habitat fragmentation - causes a decrease in biodiversity 2. Movement corridors – help dispersal of population to promote diversity in a population

Biodiversity hot spot – relatively small area with many endemic (unique to that area) species and a large number of endangered or threatened species a. Also hot spots of extinction, and therefore prime candidates for protection

Global changes and human activities A. Human activities such as farming alter nutrient cycles 1. Ex. Nitrogen depleted by crops 2. Livestock activities cause excess nitrogen to enter aquatic ecosystems and cause eutrophication (explosion of plant growth leading to death of animal populations)

Acid precipitation – pH of less than 5.2 1. Often a result of the burning of wood - releases sulfur oxides and nitrogen oxides into the atmosphere where they react with water to form sulfuric acid and nitric acid

C. Biological Magnification – toxins become more concentrated in each trophic level of a food chain

Greenhouse effect – absorption of heat by the Earth due to certain atmospheric gases 1. CO2 and water vapor absorb reflected infrared radiation, and re-reflect it back to Earth 2. Global warming – increase in burning of fossil fuels has increased CO2 in atmosphere, increasing global temperatures

Ozone layer – reduces UV radiation (which can damage DNA) from the sun that reaches the Earth’s surface 1. Chlorine-containing compounds used by humans erode the ozone layer, allowing more UV radiation through

Conservation biology, which seeks to preserve life, integrates several fields: Ecology Physiology Molecular biology Genetics Evolutionary biology Restoration ecology applies ecological principles to return degraded ecosystems to conditions as similar as possible to their natural state

These organisms can take up, and sometimes metabolize, toxic molecules Bioremediation is the use of living organisms, (such as prokaryotes, fungi, or plants) to detoxify ecosystems These organisms can take up, and sometimes metabolize, toxic molecules 6 5 4 soluble uranium (µM) Concentration of 3 2 1 50 100 150 200 250 300 350 400 Figure 56.22 Bioremediation of groundwater contaminated with uranium at Oak Ridge National Laboratory, Tennessee Days after adding ethanol (b) Uranium in groundwater (a) Unlined pits filled with wastes containing uranium

Biological augmentation uses organisms to add essential materials to a degraded ecosystem

Cuyahoga River Fire - 1969

EPA loosened compliance standards for air pollutants Penalties companies are forced to pay for violating pollution regulations have dropped by 49% over the last year Injunctive relief ($ polluters pledge to spend in order to remediate their pollution) was reduced by 65% from 2016 to 2017 EPA is proposing to repeal requirements to reduce wasted methane from oil and gas drilling Proposed 2019 budget cuts funding for EPA by 25% EPA put a two-year suspension on the Clean Water Rule Interior Department implemented policies to speed up oil and natural gas drilling, including limiting protest periods for sales to 10 days EPA considering allowing spraying of thiamethoxam (a pesticide that is acutely toxic to bees) on the most widely grown crops in the US Repealed requirements for frackers to disclose the ingredients chemical cocktails they use