3/30/2009 Acidification and Amphibian Declines Brant Pace WFS 433 March 31, 2009 Outline • Introduction • Evidence • Problems • Importance Acidification of streams – How can it occur? • Acid precipitation • Snow Melt • Percolation Through Foliage 1
3/30/2009 Acid Precipitation • Negatively charged particles such as sulphur dioxide (SO 2 ), nitrogen oxide (NO x ) and ammonium (NH 4 ) ( 4 ) released into the atmosphere Acid Precipitation • These particles react in the atmosphere to form acids • Acids then transferred to • Acids then transferred to the ground by wet deposition (attached to small airborne particles) and wet deposition (attached to droplets of rain, snow, sleet, etc.) Acid Rain Video Snow Melt • Acid that has been tied up in the snow all winter is released into the soil and streams in a relatively short time y • This causes a rapid spike in acidity, known as “episodic acidification” Snow Melt Video 1 Snow Melt Video 2 2
3/30/2009 Percolation Through Foliage • Rain filtering through some types of foliage (particularly pine canopies) can become up to 3x more acidic Effects of Acidification on Amphibians • Decrease in activity level, foraging ability, predator evasion and effectiveness as a predator predator • Lower recruitment • Decreased egg distribution • Inhibition of egg development and reproductive activity (Green and Peloquin 2008, Harte and Hoffman 1989, Jung and Jagoe 1995) Effects of Acidification on Amphibians • Decreased aquatic invertebrate populations • Increased embryo mortality I d b t lit • Perturbation of sodium metabolism • Low growth rates • Weakening of natural defenses (immunosupression) (Beebee et al. 1989, Brodkin et al. 2003, Harte and Hoffman 1989) 3
3/30/2009 Effects of Acidification on Amphibians • Increased bacterial infection • Disruption in ion transportation • Decreased white blood cell count and viability • Direct mortality (Brodkin et al. 2003, Green and Peloquin 2008)) Why Is Acidification So Important? • Acidification has negative effects on all types of amphibians yp p and at all life stages Why Is Acidification So Important? • Negative effects are magnified when acidification is coupled with other environmental stressors, such as cold 4
3/30/2009 Why Is Acidification So Important? • Acidification has many direct negative effects on reproduction and development, both of which are essential for species sustainability Why Is Acidification So Important? • Acidification causes direct mortality References • Beebee TJC, Flower RJ, Stevenson AC, Patrick ST, Appleby PG, Flectcher C, Marsh C, Natkanski J, Rippey B, Batterbee RW. 1989. Decline of the Natterjack Toad Bufo calamita in Britain: Palaeoecological, Documentary and Experimental Evidence for Breeding Site Acidification. Biological Conservation 53:1-20. • Brodkin M, Vatnick I, Simon M, Hopey H, Butler-Holston K, Leonard M. 2003. Effects of Acid Stress in Adult Rana pipiens . Journal of Experimental Zoology 298A:16-22. • G Green LE, Peloquin JE. 2008. Acute Toxicity of Acidity in Larvae and Adults of Four LE P l i JE 2008 A t T i it f A idit i L d Ad lt f F Stream Salamander Species (Plethodontidae). Environmental Toxicology and Chemistry 27:2361-2367. • Harte J, Hoffman E. 1989. Possible Effects of Acidic Deposition on a Rocky Mountain Population of Tiger Salamander Ambystoma tigrinum . Conservation Biology 3:149- 158. • Jung RE, Jagoe CH. 1995. Effects of Low pH and Aluminum on Body Size, Swimming Performance, and Susceptibility to Predation of Green Tree Frog ( Hyla cinerea ) tadpoles. Can J Zool 73:2171-2183. 5
3/30/2009 Questions? 6
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