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Threats to Biodiversity

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Presentation on theme: "Threats to Biodiversity"— Presentation transcript:

1 Threats to Biodiversity
Photo of a forest fragment, surrounded by newly created cattle pasture in Amazonas, Brazil; Photo of a sign on St. Lucia (provided by John Battista, LSU – taken by one of his former students)

2 Extinction ? Terborgh & Van Schaik (2002), pg. 3, in Making Parks Work: “Experts estimate that extinctions are occurring at hundreds of times the rate recorded through normal times in fossil history…” [Ref. = May et al Assessing Extinction Rates in Extinction Rates] Current mass extinction could result in ~ 50% of species going extinct in 100 years (Wilson 2002) K/T (Cretaceous-Tertiary) Mass Extinction ~ 65 m.y.a.; Ended the reign of the dinosaurs P/Tr (Permian-Triassic) Mass Extinction ~ 251 m.y.a.; ~ 96% of all marine species & ~ 70% of all terrestrial species Image from Wikipedia

3 Extinction “Martha” – the last living passenger pigeon – died on Sept. 1, 1914 in captivity in Cincinnati, OH The passenger pigeon was once the most common bird in North America. "Martha", thought to be the world's last passenger pigeon, died on September 1, 1914 in Cincinnati, OH. Image of Passenger Pigeon (extinct North American bird, once found in Louisiana) from Wikipedia

4 Extinction I highly recommend David Quammen’s (1996) book (The Song of the Dodo), especially for more information about patterns of diversity, their discovery, and the current extinction crisis. I also recommend David Wilcove’s No Way Home, which describes “the decline of the world’s great animal migrations.” See Groom et al. (2006, pg. 78) “Not only are species at risk of extinction, but some processes that undergird ecosystem functions, or that are glorious in and of themselves, are put at risk from human activities...” “Not only are species at risk of extinction, but some processes that undergird ecosystem functions, or that are glorious in and of themselves, are put at risk from human activities...” Groom et al. (2006, pg. 78) Image of Dodo (extinct Indian Ocean island bird) from Wikipedia

5 Habitat destruction Invasive species Pollution Overexploitation HIPPO
E. O. Wilson (b. 1929) Invasive species Pollution Human Population Overexploitation For more information on HIPPO, see: E. O. Wilson (2002) The Future of Life, Vintage Books, NY. Photo from Wikipedia; For more information on HIPPO, see: E. O. Wilson (2002) The Future of Life 5

6 Habitat Destruction & Degradation
HIPPO Habitat Destruction & Degradation Photos of forest destruction in Brazil & Malaysia

7 Habitat Destruction & Degradation
HIPPO Habitat Destruction & Degradation “An ever-expanding network of roads, railways, rivers, and shipping lanes means that only 10 percent of the earth’s surface is now remote, defined as being at least 48 hours away from a major city. More than half of the world‘s population lives within an hour of a major city…” Image from Discover Magazine, Jan-Feb 2010 Special Issue, “Top 100 Stories of 2009” – “#92: Nowhere to Hide from the Buzz of Civilization

8 Invasive Species Kudzu Walking catfish Snakehead HIPPO
Kudzu – from China & Japan, but now across U.S. southeast. Snakehead – fishes from Asia and Africa, but have appeared in several U.S. states. Walking catfish – from southeast Asia, but now in Florida and a few other U.S. states. Walking catfish Snakehead

9 HIPPO Pollution Pollution can be thought of as an overabundance of deleterious chemicals placed into the environment, including DDT, fertilizers, carbon dioxide, etc. Ecotoxicology is one sub-discipline of biology focused on pollutants. “Photoshopped” image of airplanes from

10 Pollution HIPPO NASA image from May 24, 2010 posted on Wikipedia
Deepwater Horizon oil spill in Gulf of Mexico – oil rig explosion occurred on April 20, 2010. Note that the oil spill follows closely on the heals of severe hurricanes (Katrina [Aug. 29] & Rita [Sept. 23] 2005); also consider what might happen if a hurricane strikes during current hurricane season (2010). Up until the leak was stopped, about 4.9 million barrels of crude oil leaked into the Gulf. In contrast, Exxon Valdez oil spill in 1989 released about 260,000 to 750,000 barrels. Persian Gulf – from Wikipedia: In “Iraq dumped 400 million gallons of crude oil into the Persian Gulf” [about 9.52 million barrels]. Additionally – “somewhere around 6 million barrels (950,000 m3) of oil were lost each day” [to Kuwait oil field fires]. The photo: "NASA's Terra Satellites Sees Spill on May 24 Sunlight illuminated the lingering oil slick off the Mississippi Delta on May 24, The Moderate-Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image the same day. Oil smoothes the ocean surface, making the Sun’s reflection brighter near the centerline of the path of the satellite, and reducing the scattering of sunlight in other places. As a result, the oil slick is brighter than the surrounding water in some places (image center) and darker than the surrounding water in others (image lower right). The tip of the Mississippi Delta is surrounded by muddy water that appears light tan. Bright white ribbons of oil streak across this sediment-laden water. Tendrils of oil extend to the north and east of the main body of the slick. A small, dark plume along the edge of the slick, not far from the original location of the Deepwater Horizon rig, indicates a possible controlled burn of oil on the ocean surface. To the west of the bird’s-foot part of the delta, dark patches in the water may also be oil, but detecting a manmade oil slick in coastal areas can be even more complicated than detecting it in the open ocean. When oil slicks are visible in satellite images, it is because they have changed how the water reflects light, either by making the Sun’s reflection brighter or by dampening the scattering of sunlight, which makes the oily area darker. In coastal areas, however, similar changes in reflectivity can occur from differences in salinity (fresh versus salt water) and from naturally produced oils from plants. Michon Scott NASA's Earth Observatory NASA Goddard Space Flight Center" NASA image from May 24, 2010 posted on Wikipedia

11 “More people means more of all the other HIPPO effects” (Wilson, 2002)
Human Population “More people means more of all the other HIPPO effects” (Wilson, 2002) 12 11 2100 10 9 Modern Age 8 Old Billions of People Stone Bronze Iron Middle ? Future 7 Age New Stone Age Age Age Ages 6 2000 5 Quote from pg E. O. Wilson (2002) The Future of Life, Vintage Books, NY. 4 1975 3 1950 2 1900 1 Black Death The Plague 1800 1+ million 7000 6000 5000 4000 3000 2000 1000 A.D. A.D. A.D. A.D. A.D. A.D. years B.C. B.C. B.C. B.C. B.C. B.C. B.C. 1 1000 2000 3000 4000 5000 Image from the Population Reference Bureau © 2006

12 Overexploitation Atlantic Cod HIPPO
Mark Kurlandsky’s book chronicles the collapse of several cod fisheries. See also: K. T. Frank et al Trophic cascades in a formerly cod-dominated ecosystem. Science 308:

13 Jared Diamond’s “Evil Quartet”
Jared Diamond (b. 1937) Habitat destruction & fragmentation Introduced species Overkill Secondary or cascade effects For info. on Diamond’s “Evil Quartet” see: Diamond, J Overview of recent extinctions. Pp in M. Pearl & D. Western (eds.), Conservation for the Twenty-first Century. Oxford U. Press, Oxford, UK. Photo from Wikipedia 13

14 Compounded Effects & Synergies
Erosion of biodiversity in a site often results from multiple causes Curran et al. (1999) Science Impacts of logging are exacerbated through increased frequency of El Niño events The relative importance of each different cause of biodiversity loss varies from case-to-case. At times, multiple causes give rise to bigger effects on biodiversity than would occur if each process had occurred alone. Curran, L. M., I. Caniago, G. D. Paoli, D. Astianti, M. Kusneti, M. Leighton, C. E. Nirarita & H. Haeruman Impact of El Niño and logging on canopy tree recruitment in Borneo. Science 286: Image of shrinking forest cover on Borneo from 14


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