Threat to Species: Extinction Most serious aspects of the loss of biodiversity extinction of a species Extinction when no number of the species remain

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1 THREATS BIOLOGICAL DIVERSITY ANI MARDIASTUTI DEPARTMENT OF FOREST CONSERVATION FACULTY OF FORESTRY BOGOR AGRICULTURAL UNIVERSITY 2002

2 Threat to Species: Extinction Most serious aspects of the loss of biodiversity extinction of a species Extinction when no number of the species remains alive anywhere in the world Extinction in the wild 4 individuals of a species remains alive only in captury or other humans, controlled situation Przwewalski s horse Pere David s deer

3 Globally extinct Extinction Locally extinct: no longer found in an area it once inhabited but is still found else where in the wild Ecological extinct: Persists at such reduced number that is effects on the other species inits community are negligible

4 Past Extinction: Natural Causes 9 episodes of high rates of extinction 5 mass extinction Earth: Form 4,5 billion years ago 600 million years ago, the live began Mass extinction: Ordovician, etc. (see page 78 of Primack)

5 Human Caused Extinction Insects Vertebrates Flowering plants Reached their greatest diversity about 30,000 years ago After human arrived: 74-86% of the megafauna (44 kg: 100 lbs) extinct, due to: Hunting Habitat reduction

6 Statistic: Birds and mammals Since 1600 : 83 mammlas (2.1%) (exploited in the last 150 years) 113 birds (1.3%) Rate of extinction: 1 species for every 10 years ( ) 1700) 1 species for every 1 years ( ) 1950) Extinct x greater than the past extinction Fossil record: 1 species every million years Highest extinction rates islands Endemic Speciation, reduced levels of competition,predation, threat of diseases Example: Hawaiian birds Mongoose

7 Vulnerable to extinction: 1. Species with a very narrow geographical range 2. Species with only one or a few populations 3. Species in wich population size is small 4. Species with low population density 5. Species that need a large home range

8 Vulnerable to extinction (continue): 6. Species that have large body size 7. Species with low rates of population increase 8. Species that are not effective dispersion 9. Species that migrate 10. Species with little genetic variability

9 Vulnerable to extinction (continue): 11. Species with specialized niche requirements 12. Species that are characteristically found in stable environment 13. Species that form permanent or temporary aggregations 14. Species that are hunted or harvested by people

10 Threat to ecosystem, community due to an ever increasing use of the world s natural resources by the expanding human population Habitat destruction Habitat fragmentation Habitat degradation (including pollution) Introduction of exotic species The increase spread of disease The overexploitation of many species for human use

11 A. Destruction of Habitat Due to: a. Deforestation: Commercial logging Cultivation of corps Fuelwood production Cattle ranching b. Desertification

12 Destruction of Habitat (continue) c. Catastrophic events: Fire Flood Volcanic eruption Other human development (dams, cities, industry,recreational sites, etc)

13 B. Fragmentation Habitat fragmentation is the process where by a large, cotinuious area of habitat is both reduced in area and divided into two or more fragment Habitat fragment vs Original habitat 1. Fragment have a greater amount of edge for the area of habitat 2. The centre of each habitat fragment is closer to an edge

14 Fragmentation (continue) Edge effects: Microcilmatic changes in light and temperature Wind Increased incidence of fire Increased predation and competition from exotic and pest species

15 C. Habitat Degradation a. Pesticide pollution b. Water pollution c. Air pollution: Acid rain Ozone Toxic metals c. Global climate changes Changes in the temperate zones Changes in the tropics Rising sea level Changes in plant population

16 D. Introduction of Exotic Species Exotic species alien species Why introduce exotic species? European colonization Horticulture and agriculture Accidental transport Effects of exotic species greatest on island Exotic species lead to exotic disease

17 E. Increased Spread of Diseases Diseases may be the single preatest threat to same rare species Diseases may spread from one species to anothers Diseases that are not obvious in one species can kill realted species

18 Increased Spread of Diseases (continue) Captive species kept in crowded conditions can escolate the spread of diseases Diseases transmitted to new parts of the world have particular powerful adverse effect on endemic species Human can transmit diseases to captive animals Once they are infected with exotic diseases, it may be impossible to return animals to the wild

19 F. Overexploitation Traditional hunting commercial hunting Overexploitation by humans 37% vertebarates became endangered

20 Human activities that have an impact on primates number Activity Logging Hunting / removal Removal of substrate Reduction of diet Fragmentation of habitat Reduction of gene flow Inbreeding Effects No access to isolated limiting resources (e. g., scarce minerals) Change in forest / open land ratio Changes in relative populations of different species Stress Diminished reproduction Reduction in density Increased demographic fluctuations Stress

21 Human activities that have an impact on primates number Activity Nontimber resources collection Silvicultural treatments Coastal zone development Forest clearance Shifting cultivation Reduction in density Effects Removal of substrate for prey species (e. g., insect) Poisoning of noncommercial trees Poisoning of animals who consume products from these trees Removal of mangrove Elimination of proboscis monkey Removal of substrate, food Elimination of forest spcesies Creation of open areas Increase of open-space dwellers Increase in crop raiders Reduction of forest species

22 Threats Biological Diversity 1. Treat to species: Extinction 2. Extinc Category 3. Past extinction: Natural Causes 4. Human Caused Extinction 5. Vulnerable to Extinction 6. Threat to Ecosystem 7. Habitat Destruction 8. Habitat Fragmentation 9. Habitat Degradation 10. Introduction of Exotic Species 11. The Increase Spread of Diseases 12. Overexploitation 13. Human Activities That have an Impact on Primates Number