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Cc Tropical Humid Veg


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Surasinghe, T. D. (2006). Impacts of climate change on tropical humid vegetation. Proceedings of the International Conference on Humid Tropical Ecosystems. Changes, Challenges, Opportunities. Organized and hosted by the National Science Foundation of Sri Lanka and National MAB Committee in collaboration with the International Man and Biosphere Reserve Secretariat, UNESCO, Kandy, Sri Lanka. December 2006.

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Cc Tropical Humid Veg

  1. 1. EFFECT OF CLIMATE CHANGE ON TROPICAL HUMID VEGETATION Thilina Dilan Surasinghe Department of Zoology University of Sri Jayewardenepura Sri Lanka
  2. 2. WHAT IS CLIMATE CHANGE…….? Human activities – industrial and vehicle emission Greenhouse gases like CO 2 , CH 4 , NO to concentrate in the atmosphere Trap IR radiation form sun – Enhanced Greenhouse Effect Increment in the global ambient temperature and sea surface temperature – Global Warming Influences the dynamics of global air currents, hydrological cycle and circulations of the ocean waves Affects all the climate scenarios in global scale changes in rainfall patterns, sea level rise, potential droughts, flash floods, and heat waves.
  3. 3. MASS SCALE MODIFICATION IN THE TROPICAL HUMID VEGETATION <ul><ul><li>Structure and Composition </li></ul></ul><ul><ul><ul><li>Conversion of rainforests into grasslands or scrublands </li></ul></ul></ul><ul><ul><ul><li>Desertification of tropical biomes </li></ul></ul></ul><ul><ul><ul><li>Reduced biodiversity among floral elements </li></ul></ul></ul><ul><ul><ul><li>Dissociation of floral communities </li></ul></ul></ul><ul><ul><li>Dynamics </li></ul></ul><ul><ul><ul><li>Growth and maturity </li></ul></ul></ul><ul><ul><ul><li>Reproduction </li></ul></ul></ul><ul><ul><ul><li>Regeneration </li></ul></ul></ul><ul><ul><ul><li>Ecological Successions </li></ul></ul></ul><ul><ul><li>Magnitude </li></ul></ul><ul><ul><ul><li>Reduced extent of tropical humid forest coverage </li></ul></ul></ul><ul><ul><ul><li>Restriction of humid forests into mountain tops </li></ul></ul></ul><ul><ul><ul><li>Virtual disappearance of tropical moist lowland forests </li></ul></ul></ul>
  4. 4. VEGETATION SHIFT <ul><li>Global warming and climate change </li></ul>Unfavorable environmental conditions in tropics (high temperature, low precipitation, low humidity) Species seek for the ideal environment (Suitable environmental/climatic conditions) Polar regions become relatively warmer Tropical humid vegetation realm moving pole-ward
  5. 5. DISTRIBUTION CHANGES AND RANGE RESTRICTIONS <ul><li>Climate change and global warming </li></ul>Modify gross environmental conditions and microhabitat features Declination of availability in preferred habitats of environmentally sensitive floral species decreases Constriction of biogeographic range Distribution limitations of floral elements and floral assemblages
  6. 6. CONSEQUENCES OF RANGE RESTRICTION <ul><li>Limited distribution </li></ul>Scarcity of essential biological & spatial resources Decreased population size Inability to sustain the minimum viable population Increased inbreeding Extinction!!!!!!!!!!
  7. 7. EFFECT ON ECOSYSTEM PRODUCTIVITY <ul><li>Decline in net primary production </li></ul><ul><ul><li>Heat stress damages chloroplast & reduces </li></ul></ul><ul><ul><li>photosynthesis </li></ul></ul><ul><li>Enhanced heterotrophic respiration </li></ul><ul><ul><li>High temperature increases O 2 demand </li></ul></ul><ul><ul><li>Temperature induced increased metabolism </li></ul></ul><ul><li>Growth retardation </li></ul><ul><ul><li>Moisture stress Physiological stress </li></ul></ul><ul><ul><li>Heat stress Environmental stress </li></ul></ul><ul><ul><li>Energy wastage in respiration </li></ul></ul><ul><li>Reduction in net ecosystem production as </li></ul><ul><li>consequences of…….. </li></ul>
  8. 8. INCREASED VULNERABILITY TO PESTS AND DISEASES Low Productivity Moisture stress Heat stress High energy wastage Metabolic chaos High susceptibility on pest outbreaks and diseases Low immunity Prolonged droughts Growth retardation and regeneration
  9. 9. INVASION BY WEEDY AND ALIEN SPECIES <ul><li>High ambient temperature favor weedy (unnatural) species and heat loving invasive plant species by promoting… </li></ul><ul><ul><li>Increased seed production and dispersal </li></ul></ul><ul><ul><li>Increasing longevity of plant life-span </li></ul></ul><ul><ul><li>High seed viability </li></ul></ul><ul><ul><ul><li>Expand their range by invading into forests under constriction of natural forest vegetation. </li></ul></ul></ul><ul><ul><ul><li>Diminished reproductive success of tropical humid forests </li></ul></ul></ul>
  10. 10. DISSOCIATION OF SYMBIOTIC COMMUNITIES <ul><li>Obligatory symbiotic associations are essential for sustainability of tropical humid vegetation </li></ul><ul><ul><li>For instance… </li></ul></ul><ul><ul><ul><li>Seed dispersal by frugivores: primates, bats, birds </li></ul></ul></ul><ul><ul><ul><li>Pollination by Insects and birds </li></ul></ul></ul><ul><ul><ul><li>Mycorrhizae association between orchids and fungi </li></ul></ul></ul><ul><li>The component species of symbiotic associations respond to climate change in different rates and different magnitudes </li></ul><ul><li>Hence, the associations shatter with the segregation of component species endangering the life cycle of the floral element </li></ul>