Biodiversity & Conservation

Transcription

1 Biodiversity & Conservation Professor Andrea Garrison Biology 3A Illustrations 2014 CENGAGE Learning

2 Ecosystem Services Ecosystems important to our well-being Provide us with variety of direct and in direct benefits (valued as high as $33 trillion) Source of food and genes Source of medicines Natural pest control and pollinators Jobs Natural processes purify our water and air Carbon sequestration Flood and erosion control Recreation Biodiversity & Conservation 2

3 Ecosystems & Biodiversity Healthy ecosystems have high biodiversity Species richness, genetic variation Biodiversity keeps ecosystems functioning At level of communities, ecosystems and biosphere Biodiversity has intrinsic value Humans just one of millions of species People often emotionally/spiritually connected to natural landscapes, etc. Biodiversity enhances our existence beyond its direct and indirect benefits to us Biodiversity & Conservation 3

4 Threats to Biodiversity Species extinctions decrease biodiversity Important to protect species; especially endangered and threatened species 1973 U.S. Endangered Species Act defines an endangered species as a species that is in danger of extinction throughout all or a significant portion of its range Biodiversity & Conservation 4

5 Threats to Biodiversity Habitat destruction Deforestation Biodiversity & Conservation; Illustration 2010 Pearson Education, Inc. 5

6 Threats to Biodiversity Habitat destruction Desertification results from clearing or overgrazing large tracts of land Loss of vegetation More runoff in rainy season Groundwater table recedes Less surface water results in less plant life Soil accumulates high concentrations of salt (if irrigated areas) Topsoil erosion Previously vegetation rich habitat becomes desert Biodiversity & Conservation 6

7 Threats to Biodiversity Habitat Fragmentation Human land use breaks up natural habitat into smaller areas divided by roads and cities Smaller patches of intact habitat Sustain smaller populations of organisms Lower carrying capacity Problem for higher trophic levels Many species won t cross roads, etc. Reduced gene flow between populations Edge effects further decrease habitat area Biodiversity & Conservation 7

8 Threats to Biodiversity Edge effects Human activities at borders of habitat disrupt quality of habitat Noise Pollution Extra sunlight, wind, rain at edge of forest Biodiversity & Conservation; photos 2013 Pearson Education, Inc. 8

9 Threats to Biodiversity Edge effects Habitat fragments have more edge effects than larger regions of habitat Biodiversity & Conservation 9

10 Threats to Biodiversity Invasive (exotic) species Outcompete and prey on native species Biodiversity & Conservation 10

11 Threats to Biodiversity Invasive (exotic) species Introduce diseases to which native species have no previous exposure, no resistance Devastating outbreaks Ex: chytrid fungus infection is at least partially responsible for drastic declines in amphibian population world-wide (along with habitat destruction and pollution) Traced back to African clawed frogs imported for biological research and the pet trade Biologists hypothesize that climate change has facilitated the growth of the fungal species over the last 35 years Biodiversity & Conservation 11

12 Threats to Biodiversity Overexploitation Sport or commercial hunting and fishing beyond sustainable levels Poaching protected animals for fur or body parts Biodiversity & Conservation; Illustration 2010 Pearson Education, Inc. 12

13 Kiyoshi Kimura, president of company that runs a sushi restaurant chain, poses with 220 kg bluefin tuna at Tsukiji Market, Tokyo, Jan 5, Kimura bid 14 million yen (almost $120,000) for the tuna. (Hiroto Sekiguchi/AP; from CNN;

14 Threats to Biodiversity Air pollution Biodiversity & Conservation 14

15 Threats to Biodiversity Water pollution Toxic chemicals Eutrophication Nutrient runoff in agricultural watershed Biodiversity & Conservation 15

16 Threats to Biodiversity Water pollution Nutrient run-off in agricultural watershed High algal growth Decomposition of algae as they die uses up oxygen (dark blue indicates lack of life) Biodiversity & Conservation 16

17 Threats to Biodiversity Global climate change Biodiversity & Conservation; right photo Hurricane Sandy, ABCNEWS.com; left photo 17

18 Threats to Biodiversity Hydrologic alteration Building massive dams Redistributing water to where humans want it Freshwater ecosystems among most endangered on earth Biodiversity & Conservation 18

19 Threats to Biodiversity Hydrologic alteration Changes rate and volume of water flowing in river Less, slower water downstream Seasonal changes in water flow become more regulated Disrupts life histories of aquatic organisms adapted to natural river Cold water from depths is brought to surface Interrupts spawning and other temperature regulated activities of organisms Reduces connections between streams and rivers Interrupts upstream fish migrations for spawning Facilitate introduction of nonnative species that thrive in disturbed habitat Biodiversity & Conservation 19

20 Threats to Biodiversity Biodiversity hotspots Places identified by scientists as having high biodiversity endangered by human encroachment Areas with at least 1500 endemic species (found nowhere else) and having lost at least 70% of its natural vegetation # has grown from 25 to at least 34 areas since 2000 Represent 1.4% of earth s land surface Include only remaining habitat for 45% of all terrestrial species and 35% of all terrestrial vertebrate species Biodiversity & Conservation 20

21 Threats to Biodiversity Most biodiversity hotspots in heavily populated areas Difficult to manage for the preservation of species Biologists looked for areas that would provide best outcome for their investment Identified 595 sites of imminent extinction, with total 794 endangered species; each site: Must have at least one species recognized as endangered by the World Conservation Union Must contain at least 95% of the world population of that species Must have clearly defined boundaries that separate it from surrounding areas (easier to manage species at the site) Lakes, mountain tops, forest fragments 33% of sites lie completely within protected areas 40% of sites have no protection Biologists working to protect these sites and their species Biodiversity & Conservation 21

22 Sites of Imminent Extinctions Biodiversity & Conservation 22

23 Conservation Biology Focuses on maintenance and preservation of biodiversity Uses theoretical concepts from biological disciplines of systematics, population genetics, behavior and ecology Biodiversity & Conservation 23

24 Conservation Biology Systematics Conservation plan for any area requires inventory of species Daunting task 1.6 million species named and described Estimated million living species How to inventory species when up to 98% of them have no name? Biodiversity & Conservation 24

25 Conservation Biology Population genetics Endangered species have small population sizes Genetic drift usually reduces genetic diversity within the population Reduces potential to adapt to changing environment Biologists work to increase population size and genetic diversity Breeding programs carefully monitored to prevent inbreeding Biodiversity & Conservation 25

26 Conservation Biology Ex: whooping crane Once abundant in wetland areas of Midwestern U.S. Overhunting and habitat destruction caused numbers to decline to 21 individuals in two isolated populations Population bottleneck, loss of genetic variability Developmental deformities of spine and trachea Biodiversity & Conservation 26

27 Conservation Biology Ex: whooping crane Aggressive conservation program Preserved habitats within winter and summer ranges Captive breeding program designed to minimize effects of inbreeding Currently >300 individuals in wild and captive populations Still have very low genetic variability Biodiversity & Conservation 27

28 Conservation Biology Population ecology and behavior Conservation programs require understanding of target species feeding habits, mating habits, predators, habitat preferences, movement patterns, space requirements and reproduction rates Population viability analysis (PVA) required Complex computer modeling How large must population be to ensure long-term survival (95% chance of surviving 100 years) Examine factors which may influence longevity of the population» Habitat suitability» Likelihood of catastrophes in habitat» Gene flow between populations» Other factors which influence population demographics, size or genetic variability Identifies minimum viable population size Smallest population size that fits specifications of conservation plan Always a risk If you transplant 50% of living individuals of an endangered species and program fails, there are even fewer of that species left Yellow-bellied glider (marsupial) Biodiversity & Conservation 28

29 Conservation Biology Community ecology Large regions of habitat contain more species than smaller regions Higher carrying capacity Smaller edge effects Beyond a certain area, adding area doesn t increase species richness (all species in area are represented) What is the right size area for the species under consideration? Is it physically and politically possible to get that much land set aside? US Threatened; IUCN Endangered (Int l Union for Conservation of Nature) Biodiversity & Conservation 29

30 Conservation Biology Landscape ecology Design geometry and size of protected areas Analyze large-scale ecological factors Distribution of vegetation, topography, human activity Large area vs smaller patches? Large area increase species richness Smaller patches connected by corridors seem to increase native plant species richness Corridors also allow animal movement between patches Corridors do not promote entry of exotic species Biodiversity & Conservation; photo 2013 Pearson Education 30

31 Conservation Biology Alpha diversity Biodiversity within well-defined communities Beta diversity Conservation biologists concentrate of this Biodiversity within area having wide variety of habitats and vegetation types Larger areas increase species richness (preserve greater # spp in the reserve area) Perhaps because they are more likely to include more environmental diversity Global climate change also increases need for variation of altitude within protected areas Biodiversity & Conservation 31

32 Conservation Biology Practical strategies Preserving species (in nature) requires preserving ecosystems Integrate biological research with economic and social realities 3 approaches Preservation Mixed use conservation Restoration Biodiversity & Conservation 32

33 Conservation Biology Preservation Set aside sensitive habitat where biodiversity is threatened Strict standards must be enforced for land use Sometimes people are totally excluded Sometimes access is restricted and resource exploitation controlled Requires enforcement capabilities Works well in developed nations Biodiversity & Conservation 33

34 Conservation Biology Mixed-use conservation Protect some land parcels and allow controlled use of others Ngorongoro Conservation Area (Tanzania) Tourist attraction Maasai people herd cattle and goats here Nomadic; move frequently, no permanent damage to habitat Maasai agreed to leave Serengeti National Park in return for right to remain in NCA; govt helped create infrastructure (water access) in NCA 40,000 people live in NCA without damaging habitat Biodiversity & Conservation 34

35 Conservation Biology Restoration Reestablish health of disrupted ecosystem Remove any contaminants, impediments to natural water flow, barriers to animal movement, etc. Restore natural processes such as periodic fires, floods Replant key plant communities Long-term management Biodiversity & Conservation; banner 35

36 Conservation Biology Requires local support and involvement Works best if preservation of the habitat provides local residents with some benefit Jobs as park wardens Ecotourism Biodiversity & Conservation 36