Catastrophic Events Impact on Ecosystems

Hurricanes

Hurricanes An intense, rotating oceanic weather system with sustained winds of at least 74 mph and a well-defined eye Conditions for formation: Warm water Light upper-level winds Pre-existing disturbance of thunderstorms Hurricanes produce damaging surface winds and storm surges http://www.comet.ucar.edu/nsflab/web/hurricane/311.htm http://www.create.cett.msstate.edu/cosee/cosee-lplan_view.asp?articleID=53

How Hurricanes Affect the Ecosystem

Wind Trees damaged, snapped, or uprooted http://www.nhc.noaa.gov/aboutsshws.php Hurricane waves striking sea wall  Image ID: wea00415, NOAA's National Weather Service (NWS) Collection  Category: Monsters/Hurricanes/Waves/  • High Resolution Photo Available  http://www.nhc.noaa.gov/aboutsshws.php

Storm Surge The storm surge causes sediment to erode and shift. Coastal wetlands and barrier islands take the brunt of the storm surge. Sediment erosion and deposition often affect Oyster beds Coral reefs Sea grass beds http://www.comet.ucar.edu/nsflab/web/hurricane/313.htm Many barrier islands end up shifted or eroded below sea level. http://ecosystemslab.disl.org/pdfs/Publications/Low%20Impact%20of%20Hurricane%20Katrina.pdf http://seagrassrestorationnow.com/docs/Seagrass%20Orth%20et%20al%20BiosciSeagrassCrisisDec06final.pdf http://articles.washingtonpost.com/2011-05-30/national/35264991_1_tornadoes-algae-blooms-hurricanes

Salt Water Invasion! Saltwater intrusion in lakes, streams, and wetlands change ecosystems (e.g. causes massive fish kills) The storm surge kills tree species that are not tolerant of salt water. The aftermath of Katrina. Image ID: wea02851, NOAA's National Weather Service (NWS) Collection  Location: Louisiana, Southeast coastal parishes Photo Date: 2006 January Credit: Collection of Wayne and Nancy Weikel, FEMA Fisheries Coordinators  Category: Monsters/Hurricane Katrina/  • High Resolution Photo Available 

Flooding Moves Contaminants Contaminants (e.g. chemicals used to treat crops or solid and liquid wastes) are transported into groundwater Phytoplankton blooms lead to a decrease in dissolved oxygen Lieut. Commander Mark Moran, NOAA Corps, NMAO/AOC http://www.photolib.noaa.gov/htmls/wea02495.htm http://oceanservice.noaa.gov/education/pd/living_weather/humans.html http://www.nae.edu/Publications/Bridge/TheAftermathofKatrina/ToxicandContaminantConcernsGeneratedbyHurricaneKatrina.aspx

Floods

Floods Most common of all natural hazards. Occur during heavy rains, when rivers overflow, when ocean waves come onshore, when snow melts too fast, or when dams or levees break. It can happen in every U.S. state and territory. http://sciencepolicy.colorado.edu/socasp/weather1/myers.html http://www.fema.gov/kids/floods.htm

Environmental Impact of Floods Floods are important in maintaining ecosystem habitats and soil fertility Nutrients carried by floodwaters can benefit ecosystems and crops Expand habitats for fish, birds Recharge groundwater http://gallery.usgs.gov/photos/08_17_2010_uApc6GF664_08_17_2010_24 Environmental Impacts Floods are naturally occurring phenomena that are part of the physical and biological processes which have shaped our nation's landscapes. Smith claims "More than any other environmental hazard, floods bring benefits as well as losses." He points especially to the importance of floods in maintaining ecosystem habitats and soil fertility. (Smith, pg 257). Consideration of the negative impacts of floods on the environment more often appraise the detrimental aspects of human attempts to manage flood prone areas which, in turn, disrupt the natural flood cycle. For example, the Federal Interagency Floodplain Management Task Force reports that human activities have deeply affected floodplains and the nature of flooding. Activities such as drainage of wetlands and land clearance for farming; upstream development that replaces natural vegetation with paved asphalt; and construction of channels, levees, reservoirs change the flood cycle and often result in increased runoff, destruction of riparian habitat, and increased water pollution--all of which can be considered destructive to the natural environment (FIFMTF, pp. 19-21). However, systematic assessment of the environmental benefits and costs of flooding and the environmental benefits and costs of floodplain management programs has not been done. http://sciencepolicy.colorado.edu/socasp/weather1/myers.html http://africa.ipsterraviva.net/2010/10/15/birdlife-soars-above-botswanas-floodplains/

Environmental Impact of Floods Flood-management practices have affected floodplains and the nature of flooding Wetlands drained Land cleared for farming Upstream development that replaces natural vegetation with paved asphalt Construction of channels, levees, reservoirs Natural Hazards Research and Applications Information Center http://sciencepolicy.colorado.edu/socasp/weather1/myers.html http://www.ccfcc.org/greenway_project/stormwater-flood-issues.html

Effects of Floods Destruction of riparian habitat Significant erosion can lead to more frequent flooding if not repaired Water pollution Damaged drainage systems release raw sewage Damaged buildings can be a source of toxic materials (e.g. paint, pesticide, gasoline) Effects of Floods

Animals Flooding forces many wild animals from their natural habitats. Domestic animals are also left without homes after floods. The large amounts of pooled water lead to an increase in mosquito populations. http://www.bt.cdc.gov/disasters/floods/pdf/animals.pdf

Runoff Carries Sediment and Contaminants Sediment may obscure the sunlight which inhibits photosynthesis of marine organisms Contaminants (e.g. pesticides and fertilizers) are carried into the ocean ecosystem Coral reefs are particularly at risk from the runoff from floods

Runoff Flushes Away Contaminants The sudden appearance of an overflow of water can wash away Unneeded salt Contaminants like chemical waste Debris

Tornadoes http://www.photolib.noaa.gov/bigs/nssl0210.jpg http://www.spc.noaa.gov/faq/tornado/cordell.jpg

Tornadoes A rotating column of air reaching from a thunderstorm to the ground. The most violent tornadoes can have winds up to 300 mph. http://www.spc.noaa.gov/faq http://www.photolib.noaa.gov/nssl/tornado3.html

Tornadoes Effect on Ecosystems Trees damaged, stripped, or uprooted  Open forest canopies to sunlight Fallen trees offer shelter for small animals Potential destruction of waste storage or treatment facilities or chemical plants http://www.southbridgeeveningnews.com/Articles-c-2011-06-2 http://articles.washingtonpost.com/2011-05-30/national/35264991_1_tornadoes-algae-blooms-hurricanes2-154177.113119-Tornados-longterm-impact-on-ecosystem-limited.html http://www.spc.noaa.gov/faq/tornado/f0.htm