Global Ecology and Conservation Biology 43 Global Ecology and Conservation Biology

Aim: How can we describe global ecology and conservation biology Aim: How can we describe global ecology and conservation biology? Do Now: How can we describe the difference between species diversity and species density? Homework: Read chapter 43 and complete associated concept questions.

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. 3

Figure 43.1 Figure 43.1 What will be the fate of this newly described lizard species? 4

Figure 43.2 Figure 43.2 Tropical deforestation in Vietnam 5

Conservation biology, which seeks to preserve life, integrates several fields: Ecology Evolutionary biology Molecular biology Genetics Physiology 6

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. 7

Three Levels of Biodiversity Biodiversity has three main components: Genetic diversity Species diversity Ecosystem diversity 8

Genetic diversity in a vole population Figure 43.3-1 Genetic diversity in a vole population Figure 43.3-1 Three levels of biodiversity (step 1) 9

Genetic diversity in a vole population Figure 43.3-2 Genetic diversity in a vole population Species diversity in a coastal redwood ecosystem Figure 43.3-2 Three levels of biodiversity (step 2) 10

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 11

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. 12

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. 13

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. 14

Ecosystem Diversity Human activity is reducing ecosystem diversity, the variety of ecosystems in the biosphere. More than 50% of wetlands in the United States have been drained and converted for agricultural or other use. 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 15

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 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. 16

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. 17

Aim: How can we describe global ecology and conservation biology Aim: How can we describe global ecology and conservation biology? Do Now: What are some examples of habitat destruction?

Threats to Biodiversity Most species loss can be traced to four major threats: Habitat loss Introduced species Overharvesting Global change 19

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 20

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 21

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 22

Figure 43.8 Figure 43.8 Ecological forensics and elephant poaching 23

Overfishing has decimated wild fish populations. For example, the North Atlantic bluefin tuna population decreased by 80% in ten years 24

Figure 43.9 Figure 43.9 Overharvesting 25

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. 26

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 27

Concept 43.2: Population conservation focuses on population size, genetic diversity, and critical habitat Biologists focusing on conservation at the population and species levels follow two main approaches The small-population approach The declining-population approach 28

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. A meaningful estimate of MVP requires determining the effective population size, which is based on the population’s breeding potential. 29

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 =

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

Aim: How can we describe gloabal ecology and conservation biology Aim: How can we describe gloabal ecology and conservation biology? Do Now: What is global warming? List some ways it can be limited?

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 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

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

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

Establishing Protected Areas Conservation biologists apply understanding of landscape dynamics in establishing protected areas to slow the loss of biodiversity 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 39

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

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 43

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

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

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 50

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

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 53

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, 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

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

Aim: How can we describe global ecology and conservation biology Aim: How can we describe global ecology and conservation biology? Do Now: Describe what an ecological foot print is? Do you have a large or small one? Describe your rationale.

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 The human population increased relatively slowly until about 1650 and then began to grow exponentially 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 57

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 58

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 The carrying capacity of Earth for humans is uncertain The average estimate is 10–15 billion 59

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 60

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 61

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 62

Concept 43.6: Sustainable development can improve human lives while conserving biodiversity The concept of sustainability helps ecologists establish long-term conservation priorities 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 63

Case Study: Sustainable Development in Costa Rica Costa Rica’s conservation of tropical biodiversity involves partnerships between the government, nongovernmental organizations (NGOs), and private citizens Human living conditions (infant mortality, life expectancy, literacy rate) in Costa Rica have improved along with ecological conservation 64

The Future of the Biosphere Our lives differ greatly from those of early humans, who hunted and gathered and painted on cave walls

(b) A 30,000-year-old ivory carving of a water bird, found in Germany Figure 43.31 (a) Detail of animals in a 17,000-year-old cave painting, Lascaux, France (b) A 30,000-year-old ivory carving of a water bird, found in Germany Figure 43.31 Biophilia, past and present (c) Nature lovers on a wildlife-watching expedition (d) A young biologist holding a songbird 66

Our behavior reflects remnants of our ancestral attachment to nature and the diversity of life—the concept of biophilia Our sense of connection to nature may motivate realignment of our environmental priorities