Lecture 17 Conservation Part I PDF

Ecology BIOL-2101 Prof. Dan Mennill Department of Integrative Biology, University of Windsor Lecture 17: Conservation Part I Today: Chapter14 Conservation Historic & recent extinctions  Conservation Meaning of “conservation”: 1. Stewardship of the natural world “Biologic...

Ecology BIOL-2101 Prof. Dan Mennill Department of Integrative Biology, University of Windsor Lecture 17: Conservation Part I Today: Chapter14 Conservation Historic & recent extinctions  Conservation Meaning of “conservation”: 1. Stewardship of the natural world “Biological conservation” Focus of Chapter 14 2. Sustainable use of renewable natural resources  Conservation The natural world is defined by biodiversity at genetic, species richness, and landscape scales This biodiversity is valuable: it has instrumental value, ecosystem services value, aesthetic value, and intrinsic value Genetic Species Community  Conservation Humans have caused a global biodiversity crisis, destroying biodiversity at a catastrophic rate You and I are the agents of this crisis Understanding the biodiversity crisis, and using our ecological  Natural extinctions Extinctions have always been part of natural biological change Most species that have ever evolved are now extinct (99 percent) Mass extinction events occur when large number of species go extinct simultaneously We know of six…  REPTILES AMPHIBIANS We know of five mass extinctions: 1. 440 mya: the Ordovician-Silurian extinction 25% of marine families go extinct, probably due to global cooling 2. 370 mya: the Devonian-Carboniferous extinction 19% of marine families go extinct, probably due to global climate change from volcanism  REPTILES AMPHIBIANS We know of five mass extinctions: 3. 245 mya: the Permian mass extinction 54% of families and 96% of species go extinct probably due to volcanic activity in Siberia… known as “The Great Dying” 4. 210 mya: the Triassic-Jurassic extinction 23% of families go extinct due to volcanic activity  REPTILES AMPHIBIANS We know of five mass extinctions: 5. 65 mya: the Cretacious-Tertiary (K/T) extinction 17% of families and 76% of species go extinct due to meteorite impact in Mexico’s Yucatan Peninsula  Extinction Extinction is followed by periods of adaptive radiation as newly-evolved organisms occupy now-vacant niches The Burgess Shale in British Columbia provides the world’s best evidence from 542 mya: the Cambrian explosion The Burgess Shale in British Wiwaxia Opabinia Anomalocaris  Extinction No biologist has ever witnessed a natural extinction of a species All observed extinctions have been anthropogenic We have observed natural extirpations but not natural extinctions The Karner Blue butterfly, extirpated from  Holocene extinction The modern biodiversity crisis, sometimes called the Holocene extinction, is a mass extinction comparable to previous five mass extinctions The primary difference is that this mass extinction comes  Holocene extinction Three main elements of the biodiversity crisis: 1. Species extinctions are occurring at abnormally high rates 2. Number of endangered species and species at risk is rising quickly in all countries 3. Natural communities Golden Toads went are being diminished extinct in 1989 in Costa Rica  Holocene extinction E.O. Wilson predicts extinction for half of known species by end of century Edward O. Wilson  Holocene extinction Diverse anthropogenic stressors drive the current biodiversity crisis These stressors reduce population sizes and increase fragmentation This sets the stage for extirpation FIGURE 14.4 and  Species at risk Some groups of organisms are at particular risk, including large-bodied animals No groups of organisms, or regions of Earth, are immune  Ecology Labs Labs are optional this week; if you go to chat with your GAs please go at the start of your lab period Upcoming Due Dates: Independent Project due on Brightspace by 8pm on Nov 22 Video or Infographic due by email to GAs by midnight before your final lab on Nov 28/29  Prehistoric extinctions Holocene extinction began ~12,000 years ago The Pleistocene epoch (aka “the Ice Age”) lasted from 3 mya to ~12,000 years ago The Holocene epoch began as the last glaciers retreated, ~12,000 years ago FIGURE 14.6  Prehistoric extinctions The Pleistocene overkill hypothesis: migrating humans effectively hunted large animals People colonized Alaska ≥12,000 Extinction years ago, of and then 80% of the extant approx. the rest large of Americas mammals coincides with the colonization of North America by humans  Prehistoric extinctions In North America, early humans drove to extinction: 10 species of horse 4 species of camel 4 species of mammoth 2 species of bison Giant Armadillo  Prehistoric extinctions Predators and scavengers also went extinct: – 2 species of cheetah – Dire wolf – Giant short-faced bear – American lion – Sabre-toothed tiger  Prehistoric extinctions Pre-historic extinctions of large animals have coincided with human colonization around the globe: Australia and New Guinea (≥40,000 ya) Madagascar (1,500 ya) New Zealand (1,000 ya) Many other island Moas went extinct locations ~800 years ago in FIGURE 14.7 New Zealand  Island vulnerability Species restricted to oceanic islands are especially vulnerable to extinction Most extinctions that have occurred since 1500 have been island endemics Island endemics may not show aversion to predators and have Thylacine went extinct from island no other “source of Tasmanaia in  Recent extinctions Many extinctions have occurred recently Dodos were flightless pigeons on Mauritius in the Indian Ocean Hunted for food and devastated by introduced alien species Dodo “specimen” in Mauritius was French Museum of Natural History colonized in 1598; the dodos was extinct by 1662  Recent extinctions Great Auks were flightless seabirds in eastern Canada Eaten historically by Canada’s first people, it was overharvested by European sailors Extinct by 1852 Great Auk FIGURE 14.8 specimen  Recent extinctions Passenger pigeons were the most abundant bird on Earth; 3-5 billion individuals in North America “There are wild pigeons in winter beyond number or imagination; I have seen three or four hours together flocks in the air so thick that they shadowed the sky from us.”  Recent extinctions One flock was reported to be 60 m wide and 144 km long, containing 2 billion Pigeonsanimals were hunted for food Michigan’s harvest in just one year (1869) was 1 billion Passenger Pigeons Populations declined precipitously due to over- harvest The last passenger pigeon, named Martha, died in the Martha, 1914 Cincinnati Zoo in 1914  Recent extinctions Ivory-billed Woodpecker was North America’s largest woodpecker It was never common because breeding pairs occupied large landscapes But they began to decline through the late 1800’s… Ivory-billed Woodpecker in Ivory-billed Woodpecker (Campephilus principalis)  Last confirmed sighting: a female in Louisiana in 1944  Causes of anthropogenic extinction Over- harvesting Introductio n of alien species Habitat destructio n FIGURE 14.1  Habitat destruction Anthropogenic habitat loss is considered the leading cause of the modern biodiversity crisis in terrestrial ecosystems In aquatic ecosystems, over- harvesting is the leading cause of the modern biodiversity crisis  Habitat destruction Tropical forests support most of Earth’s biodiversity Rampant conversion of tropical forest to agricultural land is fuelled by food exports to temperate countries Slash and burn agriculture and industrial agriculture operate with increasing efficiency  Alien species Alien species (invasive species) a global problem Introductions may be deliberate or accidental Alien species compete with native species Alien species are diverse, from pathogens (e.g. chestnut blight) to insects (e.g. Asian long- horned beetle) to plants and animals Purple Loosestrife  Alien species Zebra mussels have had a particularly strong effect in the Great Lakes FIGURE 14.12  Recommended reading if these topics  Summary Biological conservation is the stewardship of the natural world Mass extinctions punctuated the evolution of life on Earth, including five well-known mass extinctions in the fossil record Humans are driving the sixth mass extinction: the Holocene extinction Mechanisms of the sixth