53. Conservation Biology

What is a major advantage of herbicide-resistant crops?

The use of organisms to add essential materials to degraded systems defines __________.

__________ is the science of facilitating the return of a degraded ecosystem to a more natural condition.

One characteristic that distinguishes a population in an extinction vortex from most other populations is that a. it is a rare, top-level predator. b, its effective population size is lower than its total population size. c. its genetic diversity is very low. d. it is not well adapted to edge conditions.

Complete the following map, which organizes some of the key concepts of conservation biology.

What does species richness refer to? Select True or False for each statement. T/F the number of species in an area T/F the evenness of species in an area T/F the functional diversity of a species in an area T/F the phylogenetic diversity of species in an area

Carbon dioxide functions as a greenhouse gas by          . a. interfering with water's ability to absorb heat; b. increasing the random molecular motions of oxygen; c. allowing radiation from the sun to reach Earth and absorbing the re-radiated heat; d. splitting into carbon and oxygen and increasing the rate of cellular respiration

The main cause of the increase in the amount of CO2 in Earth's atmosphere over the past 150 years is a. increased worldwide primary production. b. increased worldwide standing crop. c. an increase in the amount of infrared radiation absorbed by the atmosphere. d. the burning of larger amounts of wood and fossil fuels.

Which of these statements best describes what conservation biologists mean by the 'the rapid loss of biodiversity'? a. Introduced species, such as starlings and zebra mussels, have rapidly expanded their ranges. b. Harvests of marine fishes, such as cod and bluefin tuna, are declining. c. The current species extinction rate is as much as 100 times greater than at any time in the past 100,000 years. d. Many potential medicines are being lost as plant species become extinct.

What community property does the red arrow in the model represent? a. low resilience b. high resilience c. low resistance d. high resistance

A mass extinction                   . a. is global in scale; b. affects many different groups of organisms; c. is caused only by human activity; d. A and B are correct; e. A, B, and C are correct

An ecological footprint                   . a. is the position an individual holds in the ecological food chain; b. estimates the total land area required to support a particular person or human population; c. is equal to the size of a human population; d. helps determine the most appropriate wastewater treatment plan for a community; e. is often smaller than the actual land footprint of residences in a city

What is the single greatest threat to biodiversity? a. overharvesting of commercially important species b. habitat alteration, fragmentation, and destruction c. introduced species that compete with native species d. novel pathogens

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as a. restoration ecology. b. thermodynamics. c. eutrophication. d. biogeochemistry.

Which of the following currently poses the single greatest threat to biodiversity? a. invasive species b. overhunting c. habitat loss d. pollution

What is a biodiversity 'hotspot'? a. an area where an all-taxon survey is under way b. an area where an environmental sequencing study has been completed c. a habitat with high NPP d. an area with high species richness and high threat to those species

The burning of fossil fuels                   . a. releases carbon dioxide to the atmosphere; b. primarily occurs as a result of human activity; c. is contributing to global warming; d. is possible thanks to photosynthesis that occurred millions of years ago; e. all of the above are correct

Current rates of species extinction appear to be approximately                    historical rates of extinction. a. equal to; b. 10 times lower than; c. 10 times higher than; d. 50 to 100 times higher than; e. 1000 to 10,000 times higher than

Which of the following is characteristic of endemic species? a. They are often found in biodiversity hot spots. b. They are distributed widely in the biosphere. c. They require edges between ecosystems. d. They are often keystone species whose presence helps to structure a community.

What is the primary threat in marine environments?

Which of the following strategies would most rapidly increase the genetic diversity of a population in an extinction vortex? a. Establish a reserve that protects the population's habitat. b. Introduce new individuals transported from other populations of the same species. c. Sterilize the least fit individuals in the population. d. Control populations of the endangered population's predators and competitors.

Ospreys and other top predators are most severely affected by pesticides such as PCBs because they a. are especially sensitive to chemicals. b. have very long life spans. c. store the pesticides in their tissues. d. consume prey in which pesticides are concentrated.

Why is the common phrase 'humans and animals' not accurate in biology? Suggest one way that a more scientific outlook could boost conservation efforts.

Which cause of extinction results from humans' direct use of a species? a. overexploitation; b. habitat fragmentation; c. pollution; d. introduction of competitors or predators; e. global warming

Which of the following statements about protected areas established to preserve biodiversity is true? (A) About 25% of Earth's land area is now protected. (B) National parks are the only type of protected area. (C) Management of a protected area does not need to be coordinated with management of the surrounding area. (D) It is especially important to protect biodiversity hot spots

Of the following statements about protected areas that have been established to preserve biodiversity, which one is not correct? a. About 25% of Earth's land area is now protected. b. National parks are one of many types of protected areas. c. Management of a protected area should be coordinated with management of the land surrounding the area. d. It is especially important to protect biodiversity hot spots.

Movement corridors are a. the routes taken by migratory animals. b. strips or clumps of habitat that connect isolated fragments of habitat. c. landscapes that include several different ecosystems. d. edges, or boundaries, between ecosystems.

Biologists claim that the all-taxa survey now under way at the Great Smoky Mountains National Park in the United States will improve their ability to estimate the total number of species living today. Discuss the benefits and limitations that this data set will provide in understanding the extent of global biodiversity.

With limited resources, conservation biologists need to prioritize their efforts. Of the following choices, which should receive the greatest attention for the goal of conserving biodiversity? a. a commercially important species b. all endangered vertebrate species c. a declining keystone species in a community d. all endangered species

Some biologists prefer to focus efforts on preserving endangered species while others prefer to focus on preserving ecosystems. What is your advice to biologists, based on the evidence from this chapter?

Which of the following human activities generates the most carbon dioxide? a. driving; b. cooking; c. bathing; d. using aerosol sprays

Which of the following statements about protected areas is not correct? a. We now protect 25% of the land areas of the planet. b. National parks are only one type of protected area. c. Most reserves are smaller in size than the ranges of some of the species they are meant to protect. d. Management of protected areas must coordinate with the management of lands outside the protected zone.

Explain why the construction of wildlife corridors can help maintain genetic diversity in a fragmented landscape.

What are the three levels of biological diversity? Explain how human activities threaten each of these levels.

What is rapid eutrophication? What steps might be taken to slow this process?

The population size of mountain pine beetles in the American Northwest has long been held in check by freezing temperatures during the winters. As winters warm, populations of pine beetles are increasing, killing whitebark pine forest. Grizzly bears rely on the nuts of whitebark pine trees. Do you think climate change is affecting the fitness of the grizzly bear population? a. No, because climate change is not a problem yet. b. No, because climate change is affecting the beetles, not the bears. c. Yes, because climate change is decreasing the food supply of the bears, which means they will be less strong. d. Yes, because climate change is decreasing the food supply of the bears, which is likely to reduce their ability to survive or reproduce.

Suppose that record snows blanket your campus this winter. Your friend says this is proof that global warming isn't really occurring. What is the flaw in your friend's logic? a. The average temperature of the Earth is not actually increasing. b. Global warming refers to temperatures, but snow is a type of precipitation. c. While the average global temperature is increasing, local temperatures and precipitation (weather) will vary. d. Your friend is confusing global warming and global climate change.

Which of the following actions can reduce humanity's ecological footprint? a. reducing our dependence on fossil fuels; b. reducing meat consumption; c. living in higher density settlements; d. better management of human wastewater; e. all of the above

One advantage of preserving more than one population of an endangered species at more than one location is                   . a. a lower risk of extinction of the entire species if a catastrophe strikes one location; b. higher levels of inbreeding in each population; c. higher rates of genetic drift in each population; d. lower numbers of heterozygotes in each population; e. higher rates of habitat fragmentation in the different locations

What are 'greenhouse gases'? Why are they important to life on Earth?

The maps shown here chronicle the loss of old-growth forest (more than 200 years old) that occurred in the United States. In your opinion, under what conditions is it ethical for conservationists who live in the United States to lobby government officials in Brazil, Indonesia, and other tropical countries to slow the rate of loss of old-growth forest?

During the Carboniferous period, plant growth was extensive but rates of decomposition slowed (probably due to the formation of vast, oxygen-poor swamp habitats). As a result, large amounts of biomass accumulated in terrestrial environments (much of this biomass is now coal). The fossil record indicates that atmospheric oxygen increased, atmospheric carbon dioxide decreased, and global temperatures dropped. Explain why.

What are the causes and possible consequences of climate change? Why is international cooperation necessary if we are to solve this problem?

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. Based on what you have learned in this chapter about global trends in terrestrial ecosystems, what is currently the largest threat to the wet tropical forests in Central America? a. habitat destruction, such as the clearing of forests for coffee plantations b. exotic species, such as the introduction of coffee berry borers c. pollution, such as the use of pesticides in coffee plantations d. climate change, such as changes in precipitation patterns

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. a. temperate forest b. tropical dry forest c. tropical grassland d. tropical wet forest

SCIENTIFIC THINKING The human-generated increase in greenhouse gases (see Module 38.3) provides many opportunities to study the effects of climate change. For example, snowshoe hares are adapted to the climate of their habitat in the taiga of the high mountains and northern regions of North America. One adaptation is seasonal changes in fur color—a white winter coat that turns brown in the spring—that camouflage hares from a long list of predators. These color changes are triggered by day length. As increasing spring temperatures cause earlier snowmelt in the taiga, biologists have observed many white hares sitting on brown earth. Suggest how this natural experiment could be used to investigate the effects of climate change on populations and communities in the taiga ecosystem (assume historical data are available).

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. Pesticides are generally ineffective in killing coffee berry borers. Ecologist Daniel Karp and colleagues conducted a study in Costa Rica to determine if natural predators like birds reduce the beetle population. The researchers selected 12 control plots and used nets to exclude birds from 12 similar treatment plots. What is the take-home message of the graph? (Remember, * means P 6 0.05)

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. Select True or False for each statement about the effects of clear-cutting on the Amazon rain forest, then explain your reasoning. T/F Nutrient export is likely to decline. T/F Atmospheric CO2 is likely to decline. T/F Soil moisture is likely to decline. T/F Species diversity is likely to decline.

The price of energy does not reflect its real costs. What kinds of hidden environmental costs are not reflected in the price of fossil fuels? How are these costs paid, and by whom? Do you think these costs could or should be figured into the price of oil? How might that be done?

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. Look at the graph.

Why did the researchers bother to collect data from the coffee shrubs before adding the nets to treatment plots to exclude birds?

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. Researchers have measured the effects of periodic forest fires on primary productivity in Amazon rain forest plots, comparing years with average precipitation and years with severe drought. Propose which controls would be necessary for such studies.

SCIENTIFIC THINKING Researchers studied active and abandoned pika colonies at two sites (one in southeast Oregon and one in northwest Nevada) to understand how elevation might influence pika range (see Module 38.0 and Module 38.11). Sites were classified as old (no longer occupied) or current. How would you summarize the findings? Does this study support the hypothesis that pika ranges are shifting to higher elevations due to climate change? What are some limitations to describing patterns in nature as compared to doing a controlled experiment?

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. The abundance of birds and other predators of borer beetles depends on how much natural forest is left within and around the coffee plantations. What is the approximate percentage increase in borer predators per hectare if forest cover is doubled from 15 to 30 percent?

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. This box-and-arrow model summarizes some of the feedback links observed in the Amazon rain forest. Select True or False for the statements that follow, based on whether they are represented by the model. (Note that the boxes and arrows in this model are used differently than those in the nutrient cycle models). T/F The burning of fossil fuels increases atmospheric CO2. T/F Tree growth reduces atmospheric CO2. T/F The death of trees promotes the invasion of grasses. T/F An increase in CO2 increases the frequency of droughts. T/F Drought increases the frequency of forest fires.

Until recently, response to environmental problems has been fragmented—an antipollution law here, incentives for recycling there. Meanwhile, the problems of the gap between rich and poor nations, diminishing resources, and pollution continue to grow. Now people and governments are starting to envision a sustainable society. The Worldwatch Institute, a respected environmental monitoring organization, estimates that we must reach sustainability by the year 2030 to avoid economic and environmental disaster. To get there, we must begin shaping a sustainable society during this decade. In what ways is our present system not sustainable? What might a more sustainable society be like? Do you think a sustainable society is an achievable goal? Why or why not? What is the alternative? What might you do to work toward sustainability? What are the major roadblocks to achieving sustainability? How would your life be different in a sustainable society?

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. Draw a simple model to compare the relative species richness and species diversity of these two coffee plantations: one is clear-cut and planted with only coffee shrubs, the other retains some natural forest. For symbols, use a few letters to represent different species of plants and a few numbers to represent different species of animals in a square 1-ha plot.

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. Many studies have raised the concern that positive feedback loops among numerous variables in the Amazon will cause an ecosystem tipping point—a rapid and irreversible transition from forest to grassland. Use the model in Question 14 as a tool to summarize a possible sequence of effects that could cause a transition from forest to grassland.

SCIENTIFIC THINKING Will increasing atmospheric levels of CO2 make you sneeze as well as itch? Scientists studying the effects of rising CO2 levels have looked at ragweed, whose pollen is the primary allergen for fall hay fever. They grew ragweed in three levels of CO2: a pre-industrial concentration of 280 ppm, a year 2000 level of 370 ppm, and a projected level of 600 ppm. They found that pollen production increased by 131% and 320% in the plants exposed to the recent and projected CO2 levels, respectively. What was the hypothesis of this experiment? Do the results support the hypothesis? Given what you know about climate change, what other variables would you like to test, and what other measurements would you like to take?

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. Journalists must be concise when reporting science news. Why might journalists and the public struggle to understand and discuss ecosystems ecology and global warming?

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. Evaluate this statement: Leaving some natural forest in and around coffee plantations is a 'win-win' situation—a win for ecosystems and a win for farmers.

Most scientific experts agree that climate change is already occurring and has potentially catastrophic consequences for all of life on Earth. The Paris Agreement of 2015 represented a global consensus on the need to reduce greenhouse gas emissions. However, in 2017 the United States announced its intention to withdraw from the Agreement in 2020. Go online to research and summarize the main agreements reached in this historic global climate accord and the U.S. government's reasons for withdrawing. What roles do you think scientists, politicians, and citizens will need to play to cut emissions and limit global warming?

SCIENTIFIC THINKING In 1954, workers at Michigan State University began spraying the elm trees on campus annually with DDT to kill disease-carrying bark beetles. In the spring of 1955, large numbers of dead robins were found on the campus. Observers thought perhaps the robins died after eating earthworms contaminated by DDT the previous spring. Suggest how scientists could have investigated the scientific validity of this idea.