sand dunes Flashcards
ecosystem
-areas that share the same set of characteristics
-interaction of biotic and abiotic
examples of biotic components
-living organisms
-microorganisms
-trees and other plants
example of abiotic components
-soil
-climate
-relief
-geology
-drainage
the role of coastal vegetation
-protect unconsolidated sediment
-bind sediment together
-when submerged, protective layer so the surface of sediment is not directly exposed to moving water
-reduce wind speeds
2 types of coastal plants
Halophytes- can tolerate salt water around their roots
Xerophytes- tolerate very dry conditions
what is sucession
-the sequencial change in plant communities over time
-different from zonation
whats zonation
-where there is variaition in the ecology/ ecological change
features of sand dunes
-obstacles such as vegetation to trap moving sand grains
-harsh conditions, often dry and salty
-rotting seaweed brought in by storm waves add nutrients to allow pioneer species
what is beach dune interaction
-when they work dynamically together to balance and buffer large scale changes to system
what is the impact of storms on dunes
-waves causing erosion during storms
-if initial storm was particularly energetic or several storms in a rapid sucession, the breaking waves and longshore drift can remove sand from beach
secondary impact of storms on sand dunes
-lowers beach elevation
-reduces volume of sand available on the beach for aeolian processes
-reduced transport of sand back to foredune
what is an example of restoration of beach dunes
-newborough warren, wales
-strategy to increase dune mobility and amont of aeolian transport means resiliance increased
-as dunes are able to adjust to changes in waves and wind by exchanging sand with the ebach
example of vegetation in embryo dunes and its adaption
-saltwort is succulent
example of vegetation in yellow dunes and its adaption
marram grass- very long roots
example of vegetation in woodland and its adaption
pine- can survive in acidic soils
oak- can survive in alkaline soils
what happens if sand dunes are overstabelised and how
-due to the anthropogenic planting of vegetation
-creates a high dune wall
-vulnerable to storm impact as fixed nature and steep slopes promote intense erosion
-prevent dynamic exchange of sand between beach and dunes
what does dune progression result in
-small, lightly vegetated and dynamic foredunes at seaward edge
-larger more vegetated primary dunes further inland
what is the order of a sand dune
-embryo dune
-foredune
-yellow dune
-grey dune
-dune slack
-mature dune
what does more vegetation in the embryo dune allow
-allows for more humus
-meaning increased retention of nutrients and water
-meaning greater chance of soil creation
examples of dune protection
-signs
-walkways
-fences
-plantations
-boardwalks
what process often occurs in yellow and grey dunes
-blow out
what is a blow out
-form of positive feedback
-when dune system becomes unstable so a bare patch of sand is revealed
what process causes a blow out
-deflation
-the localised removal of sand
what is a dune slack
-a valley between ridges
-floods in winter as is boundary between saturated and unsaturated
-in summer is dry
-damper areas where water table is close to or at surface
