Global Ecology and Conservation Biology 43 Global Ecology and Conservation Biology

Do Now: How would cutting down trees affect the water cycle? How does burning fossil fuels affect the carbon cycle? How does using nitrogen rich fertilizers affect the nitrogen cycle?

Human Impacts on the ecosystem Whenever our actions reduce biodiversity, we reduce the stability of our ecosystem. Invasive Species Deforestation Biological Magnification Global Warming

Invasive species How does invasive species disrupt stability? Nonnative species enters an ecosystem. Usually happens through human travel Has no predators to keep in check, population rises Occupies the niche of other organisms and can lead to the elimination of native species

How does deforestation reduce stability? Humans cut down trees for farming, paper products, logging etc Trees are habitats for species. Loss of habitat results in loss of species When deforestation occurs in the rainforest, this is the greatest loss to biodiversity Deforestation also leads to global warming because there are less trees to absorb atmospheric carbon dioxide.

Herring gull eggs 124 ppm Lake trout 4.83 ppm Concentration of PCBs Figure 43.23 Herring gull eggs 124 ppm Lake trout 4.83 ppm Concentration of PCBs Smelt 1.04 ppm Figure 43.23 Biological magnification of PCBs in a Great Lakes food web Zooplankton 0.123 ppm Phytoplankton 0.025 ppm 6

Biological Magnification Top trophic levels most affected. Example: PCBs and DDT affected the egg shells of birds, resulting in decline of reduction rates. Rachel Carson wrote Silent Spring to bring problem to public Toxins in environment can also have other effects. Ex: estrogen in birth control causes feminization of fish

CO2 concentration (ppm) Figure 43.26 14.9 390 14.8 380 14.7 14.6 370 Temperature 14.5 360 14.4 CO2 concentration (ppm) 350 14.3 Average global temperature (C) 14.2 14.2 340 14.1 CO2 330 14.0 Figure 43.26 Increase in atmospheric carbon dioxide concentration at Mauna Loa, Hawaii, and average global temperatures 13.9 320 13.8 310 13.7 300 13.6 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Year 8

Global Warming Case study: coral bleaching

Overview: Psychedelic Treasure Scientists have named and described 1.8 million species Biologists estimate 10–100 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, including the newly discovered psychedelic rock gecko, toward extinction 11

Figure 43.1 Figure 43.1 What will be the fate of this newly described lizard species? 12

Figure 43.2 Figure 43.2 Tropical deforestation in Vietnam 13

Concept 43.1: Human activities threaten Earth’s biodiversity Rates of species extinction are difficult to determine under natural conditions Extinction is a natural process, but the high rate of extinction is responsible for today’s biodiversity crisis Human activities are threatening Earth’s biodiversity 14

Genetic diversity in a vole population Figure 43.3-3 Genetic diversity in a vole population Species diversity in a coastal redwood ecosystem Figure 43.3-3 Three levels of biodiversity (step 3) Community and ecosystem diversity across the landscape of an entire region 15

Genetic Diversity Genetic diversity comprises genetic variation within a population and between populations Population extinctions reduce genetic diversity, which in turn reduces the adaptive potential of a species 16

Species Diversity Species diversity is the variety of species in an ecosystem or throughout the biosphere According to the U.S. Endangered Species Act 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 near future 17

Extinction may be local or global Conservation biologists are concerned about species loss because of alarming statistics regarding extinction and biodiversity Globally, 12% of birds and 21% of mammals are threatened with extinction Extinction may be local or global 18

Philippine eagle Yangtze River dolphin Figure 43.4 Figure 43.4 A hundred heartbeats from extinction 19

Philippine eagle Figure 43.4a Figure 43.4a A hundred heartbeats from extinction (part 1: Philippine eagle) Philippine eagle 20

Yangtze River dolphin Figure 43.4b Figure 43.4b A hundred heartbeats from extinction (part 2: Yangtze River dolphin) Yangtze River dolphin 21

Ecosystem Diversity Human activity is reducing ecosystem diversity, the variety of ecosystems in the biosphere More than 50% of wetlands in the contiguous United States have been drained and converted to agricultural or other use 22

The local extinction of one species can have a negative impact on other species in an ecosystem For example, flying foxes (bats) are important pollinators and seed dispersers in the Pacific Islands 23

Figure 43.5 Figure 43.5 The endangered Marianas “flying fox” bat (Pteropus mariannus), an important pollinator 24

Biodiversity and Human Welfare Human biophilia allows us to recognize the value of biodiversity for its own sake Species diversity brings humans practical benefits 25

Benefits of Species and Genetic Diversity Species related to agricultural crops can have important genetic qualities For example, plant breeders bred virus-resistant commercial rice by crossing it with a wild population In the United States, 25% of prescriptions contain substances originally derived from plants For example, the rosy periwinkle contains alkaloids that inhibit cancer growth 26

Rosy periwinkle Figure 43.UN01 Figure 43.UN01 In-text figure, rosy periwinkle, p. 885 Rosy periwinkle 27

The loss of species also means loss of unique genes and genetic diversity The enormous genetic diversity of organisms has potential for great human benefit 28

Ecosystem Services Ecosystem services encompass all the processes through which natural ecosystems help sustain human life Some examples of ecosystem services Purification of air and water Detoxification and decomposition of wastes Crop pollination, pest control, and soil preservation Ecosystem services have an estimated value of $33 trillion per year, but are provided for free 29

Threats to Biodiversity Most species loss can be traced to four major threats Habitat loss Introduced species Overharvesting Global change 30

Habitat Loss Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere In almost all cases, habitat fragmentation and destruction lead to loss of biodiversity For example In Wisconsin, prairie habitat has been reduced by over 99.9%, resulting in the loss of up to 60% of the original plant species 31

Figure 43.6 Figure 43.6 Habitat fragmentation in the foothills of Los Angeles 32

Introduced Species Introduced species are those that humans move from native locations to new geographic regions Without their native predators, parasites, and pathogens, introduced species may spread rapidly Introduced species that gain a foothold in a new habitat usually disrupt their adopted community 33

Humans have deliberately introduced some species with good intentions but disastrous effects For example, kudzu was intentionally introduced to the southern United States 34

Figure 43.7 Figure 43.7 Kudzu, an introduced species, thriving in South Carolina 35

Overharvesting Overharvesting is human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound Species with restricted habitats or large body size with low reproductive rates are especially vulnerable to overharvesting For example, elephant populations declined because of harvesting for ivory 36

DNA analysis can help conservation biologists identify the source of illegally obtained animal products For example, DNA from illegally harvested ivory can be used to trace the original population of elephants to within a few hundred kilometers 37

Figure 43.8 Figure 43.8 Ecological forensics and elephant poaching 38

Overfishing has decimated wild fish populations For example, the North Atlantic bluefin tuna population decreased by 80% in ten years 39

Figure 43.9 Figure 43.9 Overharvesting 40

Global Change Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems Acid precipitation is rain, snow, sleet, or fog with a pH 5.2 Acid precipitation contains sulfuric acid and nitric acid from the burning of wood and fossil fuels 41

Acid precipitation kills fish and other lake-dwelling organisms Air pollution from one region can result in acid precipitation downwind For example, industrial pollution in the midwestern United States caused acid precipitation in eastern Canada in the 1960s Acid precipitation kills fish and other lake-dwelling organisms Environmental regulations have helped to decrease acid precipitation For example, sulfur dioxide emissions in the United States decreased 40% between 1993 and 2009 42

Figure 43.10 4.8 4.7 4.6 4.5 4.4 pH 4.3 4.2 Figure 43.10 Changes in the pH of precipitation at Hubbard Brook, New Hampshire 4.1 4.0 1960 ’65 ’70 ’75 ’80 ’85 ’90 ’95 2000 ’05 ’10 Year 43

Small-Population Approach The small-population approach studies processes that can make small populations become extinct 44

The Extinction Vortex: Evolutionary Implications of Small Population Size A small population is prone to inbreeding and genetic drift, which draw it down an extinction vortex The key factor driving the extinction vortex is loss of the genetic variation necessary to enable evolutionary responses to environmental change Small populations and low genetic diversity do not always lead to extinction 45

Inbreeding, genetic drift Figure 43.11 Small population Inbreeding, genetic drift Lower reproduction, higher mortality Loss of genetic variability Figure 43.11 Processes driving an extinction vortex Lower individual fitness and population adaptability Smaller population 46

Case Study: The Greater Prairie Chicken and the Extinction Vortex Populations of the greater prairie chicken in North America were fragmented by agriculture and later found to exhibit decreased fertility To test the extinction vortex hypothesis, scientists imported genetic variation by transplanting birds from larger populations The declining population rebounded, confirming that low genetic variation had been causing an extinction vortex 47

(a) Population dynamics Figure 43.12 Results 200 150 Number of male birds 100 Translocation 50 1970 1975 1980 1985 1990 1995 Year (a) Population dynamics 100 Figure 43.12 Inquiry: What caused the drastic decline of the Illinois greater prairie chicken population? 90 80 70 Eggs hatched (%) 60 50 40 30 1970–’74 ’75–’79 ’80–’84 ’85–’89 ’90 ’93–’97 Years (b) Hatching rate 48

(a) Population dynamics Figure 43.12a Results 200 150 100 Number of male birds Translocation 50 Figure 43.12a Inquiry: What caused the drastic decline of the Illinois greater prairie chicken population? (part 1: population dynamics) 1970 1975 1980 1985 1990 1995 Year (a) Population dynamics 49

Results 100 90 80 Eggs hatched (%) 70 60 50 40 30 Years Figure 43.12b Results 100 90 80 70 60 Eggs hatched (%) 50 40 30 Figure 43.12b Inquiry: What caused the drastic decline of the Illinois greater prairie chicken population? (part 2: hatching rate) 1970–’74 ’75–’79 ’80–’84 ’85–’89 ’90 ’93–’97 Years (b) Hatching rate 50

Figure 43.12c Figure 43.12c Inquiry: What caused the drastic decline of the Illinois greater prairie chicken population? (part 3: photo) 51

Minimum Viable Population Size Minimum viable population (MVP) is the minimum population size at which a species can survive The MVP depends on factors that affect a population’s chances for survival over a particular time 52

Effective Population Size A meaningful estimate of MVP requires determining the effective population size, which is based on the population’s breeding potential

Ne = Nf + Nm Effective population size (Ne) is estimated by 4Nf Nm where Nf and Nm are the number of females and the number of males, respectively, that breed successfully Conservation programs attempt to sustain population sizes including a minimum number of reproductively active individuals to retain genetic diversity 4Nf Nm Nf + Nm Ne =

Case Study: Analysis of Grizzly Bear Populations One of the first population viability analyses was conducted as part of a long-term study of grizzly bears in Yellowstone National Park It is estimated that a population of 100 bears would have a 95% chance of surviving about 200 years The Yellowstone grizzly population is estimated to include about 500 individuals, but the Ne is about 125

Figure 43.13 Figure 43.13 Long-term monitoring of a grizzly bear population 56

The Yellowstone grizzly population has low genetic variability compared with other grizzly populations Introducing individuals from other populations would increase the numbers and genetic variation Promoting dispersal between fragmented populations is an urgent conservation need

Declining-Population Approach The declining-population approach Focuses on threatened and endangered populations that show a downward trend, regardless of population size Emphasizes the environmental factors that caused a population to decline

Case Study: Decline of the Red-Cockaded Woodpecker Red-cockaded woodpeckers require living trees in mature pine forests These woodpeckers require forests with little undergrowth Logging, agriculture, and fire suppression have reduced suitable habitat

Red-cockaded woodpecker Figure 43.14 Red-cockaded woodpecker Figure 43.14 A habitat requirement of the red-cockaded woodpecker (a) Forests with low undergrowth (b) Forests with high, dense undergrowth 60

(a) Forests with low undergrowth Figure 43.14a Figure 43.14a A habitat requirement of the red-cockaded woodpecker (part 1: low undergrowth) (a) Forests with low undergrowth 61

(b) Forests with high, dense undergrowth Figure 43.14b Figure 43.14b A habitat requirement of the red-cockaded woodpecker (part 2: high undergrowth) (b) Forests with high, dense undergrowth 62

Red-cockaded woodpecker Figure 43.14c Figure 43.14c A habitat requirement of the red-cockaded woodpecker (part 3: woodpecker) Red-cockaded woodpecker 63

Red-cockaded woodpeckers take months to excavate nesting cavities In a study where breeding cavities were constructed in restored sites, new breeding groups formed only in sites with constructed cavities Based on this experiment, a combination of habitat maintenance and excavation of breeding cavities enabled this endangered species to rebound

Weighing Conflicting Demands Conserving species often requires resolving conflicts between habitat needs of endangered species and human demands For example, in the western United States, habitat preservation for many species is at odds with grazing and resource extraction industries The ecological role of the target species is an important consideration in conservation

Concept 43.3: Landscape and regional conservation help sustain biodiversity Conservation biology has attempted to sustain the biodiversity of entire communities, ecosystems, and landscapes Ecosystem management is part of landscape ecology, which seeks to make biodiversity conservation part of land-use planning

Landscape Structure and Biodiversity The structure of a landscape can strongly influence biodiversity

Fragmentation and Edges The boundaries, or edges, between ecosystems are defining features of landscapes Some species take advantage of edge communities to access resources from both adjacent areas

Figure 43.15 Figure 43.15 Edges between ecosystems 69

The Biological Dynamics of Forest Fragments Project in the Amazon examines the effects of fragmentation on biodiversity Landscapes dominated by fragmented habitats support fewer species due to a loss of species adapted to habitat interiors

Figure 43.16 Figure 43.16 Amazon rain forest fragments created as part of the Biological Dynamics of Forest Fragments Project 71

Corridors That Connect Habitat Fragments A movement corridor is a narrow strip of habitat connecting otherwise isolated patches Movement corridors promote dispersal and reduce inbreeding Corridors can also have harmful effects, for example, promoting the spread of disease In areas of heavy human use, artificial corridors are sometimes constructed

Figure 43.17 Figure 43.17 An artificial corridor 73

Establishing Protected Areas Conservation biologists apply understanding of landscape dynamics in establishing protected areas to slow the loss of biodiversity

Preserving Biodiversity Hot Spots A biodiversity hot spot is a relatively small area with a great concentration of endemic species and many endangered and threatened species Biodiversity hot spots are good choices for nature reserves, but identifying them is not always easy

Designation of hot spots is often biased toward saving vertebrates and plants Hot spots can change with climate change

Earth’s terrestrial ( ) and marine ( ) biodiversity hot spots Figure 43.18 Equator Figure 43.18 Earth’s terrestrial and marine biodiversity hot spots Earth’s terrestrial ( ) and marine ( ) biodiversity hot spots 77

Philosophy of Nature Reserves Nature reserves are biodiversity islands in a sea of habitat degraded by human activity Nature reserves must consider disturbances as a functional component of all ecosystems

An important question is whether to create numerous small reserves or fewer large reserves Smaller reserves may be more realistic and may slow the spread of disease between populations One argument for large reserves is that large, far-ranging animals with low-density populations require extensive habitats Large reserves also have proportionally smaller perimeters, reducing edge effects

Grand Teton National Park Figure 43.19 50 100 Kilometers MONTANA WYOMING Yellowstone MONTANA National Park IDAHO Figure 43.19 Biotic boundaries for grizzly bears in Yellowstone and Grand Teton National Parks Grand Teton National Park Snake R. Biotic boundary for short-term survival; MVP is 50 individuals. WYOMING Biotic boundary for long-term survival; MVP is 500 individuals. IDAHO 80

Zoned Reserves A zoned reserve includes relatively undisturbed areas surrounded by human-modified areas of economic value The zoned reserve approach creates buffer zones by regulating human activities in areas surrounding the protected core Zoned reserves are often established as “conservation areas” Costa Rica has become a world leader in establishing zoned reserves

Nicaragua CARIBBEAN SEA Costa Rica National park land Buffer zone Figure 43.20 Nicaragua CARIBBEAN SEA Costa Rica National park land Figure 43.20 Zoned reserves in Costa Rica Buffer zone PACIFIC OCEAN 82

Many fish populations have collapsed due to modern fishing practices Some areas in the Fiji islands are closed to fishing, which improves fishing success in nearby areas The United States has adopted a similar zoned reserve system with the Florida Keys National Marine Sanctuary Video: Coral Reef

Florida Keys National Marine Sanctuary Figure 43.21 GULF OF MEXICO FLORIDA Florida Keys National Marine Sanctuary 50 km Figure 43.21 A diver measuring coral in the Florida Keys National Marine Sanctuary 84

Figure 43.21a Figure 43.21a A diver measuring coral in the Florida Keys National Marine Sanctuary (photo) 85

Concept 43.4: Earth is changing rapidly as a result of human actions The locations of reserves today may be unsuitable for their species in the future Human-caused changes in the environment include Nutrient enrichment Accumulation of toxins Climate change

Nutrient Enrichment Humans transport nutrients from one part of the biosphere to another Harvest of agricultural crops exports nutrients from the agricultural ecosystem Agriculture leads to the depletion of nutrients in the soil Fertilizers add nitrogen and other nutrients to the agricultural ecosystem

Critical load is the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity Nutrients that exceed the critical load leach into groundwater or run off into aquatic ecosystems Agricultural runoff and sewage lead to phytoplankton blooms in the Atlantic Ocean Decomposition of phytoplankton blooms causes “dead zones” due to low oxygen levels

Figure 43.22 Figure 43.22 A phytoplankton bloom arising from nitrogen pollution in the Mississippi basin that leads to a dead zone 89

Toxins in the Environment Humans release many toxic chemicals, including synthetics previously unknown to nature In some cases, harmful substances persist for long periods in an ecosystem One reason toxins are harmful is that they become more concentrated in successive trophic levels Biological magnification concentrates toxins at higher trophic levels, where biomass is lower

PCBs and many pesticides such as DDT are subject to biological magnification in ecosystems Herring gulls of the Great Lakes lay eggs with PCB levels 5,000 times greater than in phytoplankton

Herring gull eggs 124 ppm Lake trout 4.83 ppm Concentration of PCBs Figure 43.23 Herring gull eggs 124 ppm Lake trout 4.83 ppm Concentration of PCBs Smelt 1.04 ppm Figure 43.23 Biological magnification of PCBs in a Great Lakes food web Zooplankton 0.123 ppm Phytoplankton 0.025 ppm 92

In the 1960s Rachel Carson brought attention to the biomagnification of DDT in birds in her book Silent Spring DDT was banned in the United States in 1971 Countries with malaria face a trade-off between killing mosquitoes (malarial vectors) and protecting other species

Figure 43.24 Figure 43.24 Rachel Carson 94

Pharmaceutical drugs enter freshwater ecosystems through human and animal waste Estrogen used in birth control pills can cause feminization of males in some species of fish

Sewage treatment plant Lakes and rivers Figure 43.25 Pharmaceuticals Farm animals Humans Toilet Manure Agricultural runoff Sludge Farms Treated effluent Figure 43.25 Sources and movements of pharmaceuticals in the environment Sewage treatment plant Lakes and rivers 96

Greenhouse Gases and Climate Change One pressing problem caused by human activities is the rising concentration of atmospheric CO2 due to the burning of fossil fuels and deforestation

CO2 concentration (ppm) Figure 43.26 14.9 390 14.8 380 14.7 14.6 370 Temperature 14.5 360 14.4 CO2 concentration (ppm) 350 14.3 Average global temperature (C) 14.2 14.2 340 14.1 CO2 330 14.0 Figure 43.26 Increase in atmospheric carbon dioxide concentration at Mauna Loa, Hawaii, and average global temperatures 13.9 320 13.8 310 13.7 300 13.6 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Year 98

CO2, water vapor, and other greenhouse gases reflect infrared radiation back toward Earth; this is the greenhouse effect This effect is important for keeping Earth’s surface at a habitable temperature Increasing concentration of atmospheric CO2 is linked to increasing global temperature

Climatologists can make inferences about prehistoric climates CO2 levels are inferred from bubbles trapped in glacial ice Chemical isotope analysis is used to infer past temperature

Northern coniferous forests and tundra show the strongest effects of global warming For example, in 2007 the extent of Arctic sea ice was the smallest on record

Range Shifts and Climate Change Many organisms, especially plants, may not be able to disperse rapidly enough to survive rapid climate change Researchers can track changes in tree distributions since the last period of glaciation to help infer future changes due to climatic warming 102

(b) 4.5C warming over next century Figure 43.27 Figure 43.27 Current range and predicted range for the American beech under two climate-change scenarios (a) Current range (b) 4.5C warming over next century (c) 6.5C warming over next century 103

Climate Change Solutions Global warming can be slowed by reducing energy needs and converting to renewable sources of energy Stabilizing CO2 emissions will require an international effort and changes in personal lifestyles and industrial processes Reduced deforestation would also decrease greenhouse gas emissions

Concept 43.5: The human population is no longer growing exponentially but is still increasing rapidly Global environmental problems arise from growing consumption and the increasing human population No population can grow indefinitely, and humans are no exception 105

The Global Human Population The human population increased relatively slowly until about 1650 and then began to grow exponentially 106

Human population (billions) Figure 43.28 7 6 5 Human population (billions) 4 3 2 Figure 43.28 Human population growth (data as of 2011) 1 8000 4000 3000 2000 1000 1000 2000 BCE BCE BCE BCE BCE CE CE 107

The global population is now more than 7 billion Though the global population is still growing, the rate of growth began to slow during the 1960s 108

Annual percent increase Figure 43.29 2.2 2.0 1.8 1.6 1.4 2011 Annual percent increase 1.2 Projected data 1.0 0.8 Figure 43.29 Annual percent increase in the global human population (data as of 2011) 0.6 0.4 0.2 1950 1975 2000 2025 2050 Year 109

The growth rates of individual nations vary with their degree of industrialization Most of the current global population growth is concentrated in developing countries Human population growth rates can be controlled through family planning, voluntary contraception, and increased access to education for females 110

Global Carrying Capacity How many humans can the biosphere support? Population ecologists predict a global population of 8.110.6 billion people in 2050 111

Estimates of Carrying Capacity The carrying capacity of Earth for humans is uncertain The average estimate is 10–15 billion 112

Limits on Human Population Size The ecological footprint concept summarizes the aggregate land and water area needed to sustain the people of a nation It is one measure of how close we are to the carrying capacity of Earth Countries vary greatly in footprint size and available ecological capacity 113

Energy use (GJ):  300 150–300 50–150 10–50  10 Figure 43.30 Figure 43.30 Annual per capita energy use around the world Energy use (GJ):  300 150–300 50–150 10–50  10 114

Our carrying capacity could potentially be limited by food, space, nonrenewable resources, or buildup of wastes Unlike other organisms, we can regulate our population growth through social changes 115

Concept 43.6: Sustainable development can improve human lives while conserving biodiversity The concept of sustainability helps ecologists establish long-term conservation priorities 116

Sustainable Development Sustainable development is development that meets the needs of people today without limiting the ability of future generations to meet their needs To sustain ecosystem processes and slow the loss of biodiversity, connections between life sciences, social sciences, economics, and humanities must be made 117