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Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
Amphibians Humid Tropics
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Amphibians Humid Tropics

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• Surasinghe, T. D. (2006). Amphibians in humid tropical ecosystems of Sri Lanka: Threats and needs for Conservation. Changes, Challenges, Opportunities. Organized and hosted by the National Science …

• Surasinghe, T. D. (2006). Amphibians in humid tropical ecosystems of Sri Lanka: Threats and needs for Conservation. 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.

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  • 1. AMPHIBIANS IN HUMID TROPICAL ECOSYSTEMS OF SRI LANKA: THREATS AND NEEDS FOR CONSERVATION Thilina Dilan Surasinghe Department of Zoology University of Sri Jayewardenepura Sri Lanka
  • 2. TROPICAL HUMID AMPHIBIANS OF SRI LANKA <ul><li>Sri Lanka’s tropical humid ecosystems are rich in amphibian diversity and endemism </li></ul><ul><li>78% of islands’ amphibian fauna are confined to humid tropics </li></ul><ul><li>Family Ranidae of Sri Lanka is exceptional with 70 of 82 species are restricted to the humid tropics </li></ul><ul><li>97% of tropical humid amphibians are endemic </li></ul><ul><li>Three endemic genera Adennmus, Nannophrys, Lankanectes </li></ul><ul><li>One endemic subfamily – Lankanectinae </li></ul><ul><li>Local tropical humid amphibian hotspots… </li></ul><ul><ul><li>Central Highlands, Knuckles Range, Sabaragamuwa Range </li></ul></ul><ul><li>Habitats of the tropical humid amphibians: </li></ul><ul><ul><li>Tropical moist lowland forests </li></ul></ul><ul><ul><li>Moist savanna </li></ul></ul><ul><ul><li>High-altitude grasslands </li></ul></ul><ul><ul><li>Tropical moist montane forests </li></ul></ul><ul><ul><li>Tropical swamp forests </li></ul></ul><ul><ul><li>Wet grasslands </li></ul></ul>
  • 3. WHY SO DIVERSE…? <ul><li>Absences of climate change in last 31000 years in rainforest refugea </li></ul><ul><ul><li>Relatively stable environment </li></ul></ul><ul><ul><li>Minimal climate induced extinction </li></ul></ul><ul><li>Speciation via geographical disjunction of distribution </li></ul><ul><ul><li>Isolated large mountain-peaks and Long spanned mountain-ranges </li></ul></ul><ul><ul><li>Geography-specific vegetation </li></ul></ul><ul><li>Favorable climatic features </li></ul><ul><ul><li>Favorable optimum habitat conditions </li></ul></ul><ul><ul><li>High year round precipitation </li></ul></ul><ul><ul><li>High relative humidity </li></ul></ul><ul><ul><li>Optimum temperature - 24-28 ºC </li></ul></ul><ul><li>Heterogeneity in terrestrial, aquatic and arboreal habitats </li></ul><ul><ul><li>High niche spaces and partitions </li></ul></ul><ul><ul><li>Vegetation complexity </li></ul></ul><ul><ul><li>High microhabitat availability and diversification </li></ul></ul><ul><ul><li>Elaborated hydrology and stream morphology </li></ul></ul>
  • 4. THREATENED STATUS OF TROPICAL HUMID AMPHIBIANS <ul><li>30 species gone extinct from humid tropics in past 10 years </li></ul><ul><ul><li>Adenomus kandianus, Nannophrys guentheri, Philautus adspersus </li></ul></ul><ul><li>All falls under Red-List Categories </li></ul><ul><ul><li>Critically Endangered – 11 ( Adenomus dasi, Microhyla karunaratnei ) </li></ul></ul><ul><ul><li>Endangered – 35 ( Philautus zorro, Polypedates longinasus ) </li></ul></ul><ul><ul><li>Vulnerable – 6 ( Ichthyophis pseudangularis, Rana aurantiaca ) </li></ul></ul><ul><ul><li>Near Threatened – 5 ( Rana temporalis, Ramnella nagaoi ) </li></ul></ul><ul><li>All the Red-Listed Sri Lankan amphibians are restricted to the humid tropics </li></ul><ul><ul><li>Tropical moist lowland/motane forests </li></ul></ul><ul><li>Most are spot endemics </li></ul><ul><ul><li>Ph. simba, Ph. lunatus, Polypedatus fastigo : Morningside </li></ul></ul><ul><ul><li>Ph. mooreorum, Ph. fulvus, Ph. hoffmanni, N. marmorata: Knuckles Hills </li></ul></ul><ul><ul><li>Ph. limbus, Ph. nemus: Haycock Hill </li></ul></ul><ul><ul><li>Ph. Alto, Ph. frankenbergi: Horton Plains </li></ul></ul>
  • 5. THREATS TO THE AMPHIBIANS <ul><li>Deforestation and habitat destruction </li></ul><ul><ul><li>Only 750 km 2 are covered with tropical humid forests </li></ul></ul><ul><ul><li>Severely disunited into 100km 2 fragments or less </li></ul></ul><ul><ul><li>Declining of population sizes </li></ul></ul><ul><ul><li>Increased inbreeding within small forest patches </li></ul></ul><ul><ul><li>Severely confront edge effect in small habitat patches </li></ul></ul><ul><ul><li>Higher vulnerability for disturbances </li></ul></ul><ul><ul><li>Lower colonization and recovery rates </li></ul></ul><ul><ul><li>Inbreeding drastically reduces the reproductive fitness/success </li></ul></ul><ul><ul><ul><li>Inbreeding depression </li></ul></ul></ul><ul><ul><ul><li>Inability to avoid predators </li></ul></ul></ul><ul><ul><ul><li>Low diseases-resistance </li></ul></ul></ul><ul><ul><ul><li>High rates of juvenile mortality </li></ul></ul></ul><ul><ul><ul><li>Reduced genetic variation </li></ul></ul></ul><ul><ul><ul><li>Accumulation of deleterious </li></ul></ul></ul><ul><ul><ul><li>mutations </li></ul></ul></ul><ul><ul><ul><li>Small clutch sizes </li></ul></ul></ul>
  • 6. <ul><li>Invasion by alien species and domestic/village species imposes threats by… </li></ul><ul><ul><li>Direct predation and competition </li></ul></ul><ul><ul><li>Habitat alteration </li></ul></ul><ul><li>Parasites and pathogens </li></ul><ul><ul><li>hamper the growth, reproductive success, physical fitness and results direct mass mortality </li></ul></ul><ul><li>Climate change </li></ul><ul><ul><li>Reduced amphibians’ distribution, abundance, feeding niches </li></ul></ul><ul><ul><li>Disappearance of cloud-born mist with warming trend dispels the humid environment for montane amphibians </li></ul></ul><ul><ul><li>Modification in vegetation structure - conversion of forests into bushlands and semi-arid torn forests </li></ul></ul>
  • 7. <ul><li>Human-induced disturbances </li></ul><ul><ul><li>Extraction of forestry resources – Firewood &amp; timber </li></ul></ul><ul><ul><li>Encroachments into forests for cultivations </li></ul></ul><ul><ul><ul><li>“ Deniya” cultivation </li></ul></ul></ul><ul><li>Agro-chemicals and other environmental pollutants </li></ul><ul><ul><li>Adverse/harmful genetic mutations </li></ul></ul><ul><ul><ul><li>Anatomical malformations </li></ul></ul></ul><ul><ul><ul><li>Functional abnormalities </li></ul></ul></ul><ul><ul><li>Chronic and acute physiological disorders </li></ul></ul><ul><ul><li>Reduced reproductive output and low juvenile survival </li></ul></ul><ul><ul><li>Mass mortalities due to direct toxicity </li></ul></ul><ul><ul><li>Food scarcity due to destruction of forest insect communities by pesticides </li></ul></ul><ul><li>Acid depositions </li></ul><ul><ul><li>Predisposition for diseases: fungus </li></ul></ul><ul><ul><li>Forest diebacks - Horton Plains </li></ul></ul><ul><ul><li>Direct mortality in adults &amp; tadpoles due to high acidity in water </li></ul></ul><ul><li>Accidental causes </li></ul><ul><ul><li>Road kills </li></ul></ul><ul><ul><ul><li>Fragmentation of extensive habitats by motor ways </li></ul></ul></ul><ul><ul><li>Operation of agricultural machinery </li></ul></ul>
  • 8. CONSERVATION <ul><li>Extension of protected area network </li></ul><ul><ul><li>Recognition of gaps in protected areas </li></ul></ul><ul><ul><ul><li>Hanthana, Knuckles foothills, Central massif foothills </li></ul></ul></ul><ul><ul><li>Recognition of local amphibian-hotspots </li></ul></ul><ul><ul><ul><li>Eg: Eastern Sinharaja and surrounding habitats </li></ul></ul></ul><ul><ul><ul><li>Agra-Bopath Sanctuary </li></ul></ul></ul><ul><li>Extenuate degradation of core-forest </li></ul><ul><ul><li>Establishment of buffer zones </li></ul></ul><ul><ul><li>Rules and regulation enforcements to minimize disturbances </li></ul></ul><ul><ul><li>Strict physical protection </li></ul></ul><ul><ul><li>Introduce alternatives for resource overexploitation </li></ul></ul><ul><li>Prevention and elimination of invasions </li></ul><ul><ul><li>Bio-control mechanisms for eradication of invasive species </li></ul></ul><ul><ul><li>Continuous monitoring for re-invasion </li></ul></ul>
  • 9. <ul><li>Efficient ecosystem management </li></ul><ul><ul><li>Introduction of preferred native vegetation </li></ul></ul><ul><ul><li>Plantation &amp; conservation of gallery forests </li></ul></ul><ul><ul><li>Provision of ideal hydrological features </li></ul></ul><ul><ul><li>Enhancing the landscape &amp; macrohabitat diversity </li></ul></ul><ul><ul><li>Management of microhabitat features – small creeks, cascades, small forest pools, artificial phytotelms, talus, and crevice </li></ul></ul><ul><li>Linkage of forest/habitat fragments </li></ul><ul><ul><li>Suitable habitat corridors to establish population processes and metapopulations </li></ul></ul><ul><li>Restoration of degraded habitats </li></ul><ul><ul><li>Reforestation with native species </li></ul></ul><ul><ul><li>Enrichment-plantation </li></ul></ul>
  • 10. <ul><li>Adopting eco-friendly agricultural practices </li></ul><ul><ul><li>Agro-forestry and organic farming </li></ul></ul><ul><li>Solutions for road mortality </li></ul><ul><ul><li>Road crossing structures: tunnel systems, wildlife bridges, underpasses, viaducts </li></ul></ul><ul><li>Species-based approaches: ex-situ conservation </li></ul><ul><ul><li>Re-introductions and translocations </li></ul></ul><ul><ul><li>Intensive recovery management for critically endangered species </li></ul></ul><ul><ul><ul><li>Clutch manipulation </li></ul></ul></ul><ul><ul><ul><li>Provision of artificial nesting sites </li></ul></ul></ul><ul><ul><li>Elimination or mitigation of species specific threats </li></ul></ul><ul><ul><ul><li>Disease prevention by quarantine regulations </li></ul></ul></ul><ul><ul><ul><li>Elimination of disease/parasite hosts/reservoirs </li></ul></ul></ul><ul><ul><ul><li>Medical provisions </li></ul></ul></ul><ul><ul><ul><li>Captive maintenance of healthy populations </li></ul></ul></ul><ul><ul><ul><li>Captive breeding/artificial propagation and releasing to the wild </li></ul></ul></ul><ul><ul><ul><li>Establishing a genome resource bank </li></ul></ul></ul>
  • 11. SOME TROPICAL HUMID AMPHIBIAN HABITATS OF SRI LANKA Agra-Bopath Sanctuary Kanneliya Forest Reserve Sinharaja MAB Reserve Knuckles Conservation Forest

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