habitat destruction

  1. Habitat destruction
    • More of a problem in quiet sandy or muddy areas
    • Human activities cause alterations of an area and badly affect the Fauna
    • Cumulative effect:
    • Multiple activities contribute to problems, especially if in small area
    • 1 person builds here-not much of a problem, but then another builds 1mi away and another etc
    • White point sewer outfall-drains LA toliets-nutrient rich
  2. There is lack of knowledge of BENEFITS of marshes, bays, sand flats etc to human beings
    • Human uses: fisheries (crabs, shrimps, fishes, fur) and nursery areas; Wildlife watching
    • Sea grass and marshes are good for juveniles
    • Storm protection
    • If more marshland, Louisiana wouldn't have been as affected and levis might not have broken
    • Marsh hay
    • Feeding area for many animals ie sea turtles (at one point)
  3. WHY does habitat destruction occur
    • Add to property taxes
    • Marshes don't pay taxes, condominiums do
    • LACK of appreciation of Value
    • Think of it as mosquito breeding ground
    • People use it as dump site
    • No beautiful coral reefs etc
    • Most there is burrowed down and small
  4. WHAT CAN HAPPEN to cause habitat destruction
    • Filling and construction
    • Diking
    • Building breakwaters and marinas
  5. Problems caused by filling/ contruction
    • Concrete, dirt and fill just dumped on top of mud or sand
    • Compaction-pressure pushed on sand /mud causes:
    • SUBSIDENCE
    • Subsidence=sinking
    • Can cause cracking in building, major dips in highways
    • Serious developer uses pilings
    • Pilling-supports heavily anchored and go way down into sand
    • Less subsidence
    • Totally destroys the marsh
  6. DIKING
    • Dike-building large barrier of earth to prevent waterflow
    • Prevents hurricane surge
    • Can get 8ft surge during hurricane
    • Vs typical 2ft tide
    • Building a dike: pile up dirt but make triangle so wave goes up and then slides back down
    • New Orleans-were cheap so they just put dirt around concrete column
    • Storm washed base away=> collapse
    • Older ones are often more stable and strong-built to last
  7. Problems with dikes
    • Water doesn't flow past dike=> marsh area closer inland can dry or have HYPERSALINE water=> lots die and can't live there
    • DREDING AND DITCHING
    • Creating channels for boats
    • Can disrupt natural flow in marsh
    • Natural channel meanders
    • Have areas where sediment accumulates and doesn't accumulate
    • Artificial channels are straight
    • Can cause erosion of marsh
    • Can cave in
    • Boat wakes-water kicked up behind it
    • The waves can cause additional erosion=>cave in
  8. Building marinas and breakwaters
    • Deflect flow of water
    • LA vs longbeach
    • Areas that were once deep become shallow
    • Deep dredged channels
    • Often stratified
    • Diffusion lacking, no gas exchange=>stratification
    • Build up at bottom, become stagnant
    • Fall storms=> mixes water=overturn
    • OVERTURN-acidic mess from bottom brought to surface by fall storm
  9. Marina problems
    • no water flow become very anaerobic=>No fish
    • Human activity can cause siltation=>bury local species , prevent feeding and /or respiration
    • If mud goes over sand=> no more gas exchange=>revent algae etc in water from being washed over shrimp clams etc to eat
    • Not dumping anything on top of it, just create tons of silt
  10. RESTORATION of habitats
    • Can it be done-Maybe
    • Mitigation-developer does something to provide equal habitat to that lost or damaged by activities
    • Replanting sea grasses, spartina, mangroves
    • Works sometimes ,but other not
    • Sediment may have been changed due to human activity
    • Doesn't have to work, just have to show effort
    • Takes years after restoring to establish
    • Often enough, damage is enough that need major hurricane or earthquake to bring it back to where it was
Author
alyspins
ID
106687
Card Set
habitat destruction
Description
habitat destruction
Updated