BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 38 Conservation Biology Modules 38.1 – 38.3

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Modern human culture and the rapidly growing global human population have created a biodiversity crisis –There is a rapid decrease in the variety of species on Earth The decline in Key deer populations is an example of this crisis –The Key deer is a miniature subspecies of the whitetail deer found only in the Florida Keys Saving the Key Deer

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Key deer was nearly exterminated by hunting in the early 1900s The National Key Deer Pine Refuge was established on Big Pine Key island in 1957 –The deer population rebounded to The Key deer is still on the endangered species list

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The human population on Big Pine Key has increased tenfold since 1967 –Development has reduced the Key deer habitat –Motorists have become the main threat to the deer's survival

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Conservation biology is a goal-oriented science that seeks to counter the biodiversity crisis Conservation biology relies on research from all levels of ecology, from populations to ecosystems

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Human alteration of habitats poses the single greatest threat to biodiversity –The loss of tropical rain forests and marine habitats are especially devastating 38.1 Habitat destruction, introduced species, and overexploitation are the major threats to biodiversity THE BIODIVERSITY CRISIS: AN OVERVIEW Figure 38.1A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Competition with introduced species also threatens many species in their native habitats –Introduced species are those that have been transferred to an area where they did not occur naturally –Examples: European starlings, pigeons, and house sparrows

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings One of the largest rapid-extinction events ever recorded occurred in Lake Victoria, East Africa –200 species of freshwater fish were lost due to the introduction of the Nile perch Figure 38.1B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Overexploitation of wildlife also threatens many species –Excessive commercial harvest or sport hunting has reduced the numbers of many species –Examples: whales, American bison, Galápagos tortoises, and numerous fish

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Preservation of biodiversity is important to humans for aesthetic, ethical and practical reasons Biodiversity provides humans with food, clothing, shelter, oxygen, soil fertility, etc. We evolved in Earth's ecosystem –Large-scale changes in the ecosystem threaten us as well as other species 38.2 Biodiversity is vital to human welfare

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Medicinal plants and their derivatives play an important role in the pharmaceutical industry –The rosy periwinkle of Madagascar provides two substances effective in the treatment of Hodgkin’s disease Figure 38.2

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The explosive growth of the human population and of technology continues today Although the populations of developing nations are growing the fastest, it is the resource consumption of the less populous, developed nations that puts a greater strain on the biosphere 38.3 Connection: Technology and the population explosion compound our impact on habitats and other species

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Table 38.3

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Oil spills, acid rain, ozone depletion, and chemical pesticides affect the entire world Figure 38.3a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chemical pesticides are concentrated in food chains by biological magnification Figure 38.3B DDT in water ppm DDT in zooplankton 0.04 ppm DDT in small fish 0.5 ppm DDT in large fish 2 ppm DDT in fish-eating birds 25 ppm DDT concentration: increase of 10 million times

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Burning of fossil fuels is increasing the amount of CO 2 and other greenhouse gases in the air 38.4 Connection: Rapid global warming could alter the entire biosphere Figure 38.4A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 38.4B Light Heat GREENHOUSE EFFECT: CO 2 lets sunlight through but retains the heat generated by the sun CO 2 Adding CO 2 to the air increases the greenhouse effect Removal of CO 2 from the air by photosynthesizing plants and algae decreases the greenhouse effect CO 2

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Projected atmospheric temperatures indicate an increase in greenhouse gases Figure 38.4C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings An increase in global temperature could have many negative effects –Change in climate patterns –Melting of polar ice –Flooding of coastal regions –Increase in the rate of species loss

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Environments are patchy –As a result, species are not evenly distributed Geographic distribution patterns for many species indicate an uneven density –Example: terrestrial birds in North and Central America 38.5 Some locations in the biosphere are especially rich in biodiversity THE GEOGRAPHIC DISTRIBUTION OF BIODIVERSITY

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Density of bird species Figure 38.5A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Biodiversity hot spots are relatively small areas with a large concentration of species Many species in these hot spots are endemic –They are found nowhere else Biodiversity hot spots can also be hot spots of extinction

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Location of some biodiversity hot spots Figure 38.5B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Endemic species are highly sensitive to habitat degradation and thus prone to extinction Many migratory species, both terrestrial and aquatic, require international protection

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Monarch butterflies migrate throughout Canada and the United States during the summer months –In the autumn months, they migrate to local sites in Mexico and California –Such overwintering populations are susceptible to habitat disturbances Figure 38.5C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Sea turtles, such as the loggerhead turtle, are threatened in their ocean feeding grounds and on land Figure 38.5D

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Habitat degradation can lead to population fragmentation –Portions of populations are split and subsequently isolated –It often results in species being designated as threatened or endangered 38.6 There are two approaches to studying endangered populations CONSERVATION OF POPULATIONS AND SPECIES Figure 38.6A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Endangered Species Act (ESA) defines an endangered species as one that is in danger of extinction throughout all or a significant portion of its range –Example: the northern spotted owl The ESA defines a threatened species as one that is likely to become endangered in the foreseeable future Figure 38.6B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Some conservation biologists believe that the smallness of a population will ultimately drive it to extinction The small-population approach –Identifies the minimum viable population size for a threatened species –Focuses on preserving genetic variation The declining-population approach diagnoses and treats the causes of a population's decline

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Identifying the specific combination of habitat factors that is critical for a species is pivotal in conservation biology The red-cockaded woodpecker requires three habitat factors –A mature pine forest 38.7 Identifying critical habitat factors is a central goal in conservation research Figure 38.7A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Low growth of plants among the mature pine trees –Controlled fires to reduce forest undergrowth Figure 38.7B, C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Increased fragmentation threatens many species –This includes those whose populations were historically highly fragmented 38.8 Connection: Increased fragmentation threatens many populations: A case study

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings One example is the endangered bull trout –It inhabits lakes, rivers, and mountain streams in northwestern Canada and the United States Figure 38.8A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The bull trout requires cold, fast-flowing streams with pebble-covered bottoms and little or no silt Figure 38.8B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Before human intervention, the bull trout population consisted of four subpopulations Figure 38.8C, left S1 S3 S2 S4 Egg-laying sites in mountain streams Regular, frequent dispersal and gene flow between subpopulations Irregular, infrequent dispersal; minimal gene flow between subpopulations

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The bull trout population has been further fragmented and reduced by –the construction of hydroelectric dams –logging –road building –mining Figure 38.8C, right s1 s3 s2 s5 s4 Mill site for silver mine Hydroelectric dam Egg-laying sites in mountain streams Clear-cut (logged) areas Roads Irregular, infrequent dispersal; minimal gene flow between subpopulations

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Conservation biologists often use computer simulations in a population viability analysis (PVA) –PVA incorporates as much information about a population's current status as available –It predicts a species' chance for long-term survival

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Conservation efforts are increasingly aimed at learning how to sustain whole ecosystems and landscapes Landscape ecology employs ecological principles to study land-use patterns –It aims to make species conservation a functional part of those patterns 38.9 Sustaining ecosystems and landscapes is a conservation priority MANAGING AND SUSTAINING ECOSYSTEMS

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Researchers often use gap analysis to study the distribution of organisms relative to landscape features and habitat types Gap analysis employs computerized maps along with information on the distribution of organisms

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 38.9A Map of vegetation patterns and river course Distribution of rare, endemic species Distribution of protected areas Final overlay map

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gap analysis can highlight areas with the greatest concentrations of rare and endangered species outside of protected areas –It can lead to sustaining the biodiversity of the whole area Figure 38.9B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Boundaries between ecosystems have their own set of features and assemblages of species Human activities can create edges that are more abrupt than those found naturally Edges and corridors can strongly influence landscape biodiversity Figure 38.10A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The increased frequency and abruptness of edges can increase the loss of species –Populations of the brown-headed cowbird, an edge-adapted species, are currently expanding –Populations of songbird species are declining Figure 38.10B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Movement corridors are strips or clumps of quality habitat that connect otherwise isolated habitat patches –They may be helpful or harmful to fragmented populations Corridors can promote dispersal and reduce inbreeding in declining populations Figure 38.10C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Restoration ecology uses ecological principles to develop ways to return degraded ecosystems to conditions as similar as possible to their natural, predegraded state There are two strategies in restoration ecology –Bioremediation –Augmentation Restoring degraded habitats is a developing science

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Bioremediation is the use of living organisms to detoxify polluted ecosystems –These organisms are usually prokaryotes, fungi, or plants –These lichens are concentrating mining wastes Figure 38.11A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Augmentation of ecosystem processes involves resupplying an area with key factors that have been removed Encouraging the growth of plants that thrive on nutrient-poor soils can hasten the rate of recovery of some tropical areas –In Puerto Rico, the legume Albizia helped set the stage for recolonization by native species Figure 38.11B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In numbers, geographic range, and capacity to alter the biosphere, our species is clearly one of the most successful ones ever to inhabit planet Earth Human attitudes and environmental awareness are of utmost importance in the search for solutions to the biodiversity crisis Sustainable development is an ultimate goal

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The gray-headed flying fox symbolizes the biodiversity crisis Habitat destruction and the killing of animals as pests has reduced the population 75% in the past 25 years Further decrease could endanger this species and hurt its ecological role in maintaining forest diversity by pollination and seed dispersal Figure 38.12

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Understanding the biosphere's limits and vulnerability and our own linkages to the natural world may help us make decisions that lead to a sustainable future