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
features of mature dune
-greater species diversity can be found as top layer of soil has developed
-heath land developed as plants still have to survive in salty conditions
whats a heath land
-open, uncultivated landscape
-poor, acidic soils
-dominated by low-growing vegetation
where do sand dunes form
beyond the areas of spring tide at the back of the beach
what are the first colonising plants of a sand dune known as
pioneer species
role of pioneer species
-begin the process of plant sucession
-modify environment by binding sand or soil with roots and add nutrients when they die and decay
what is the final community that is adjusted to the climatic conditions of the area known as
-climatic climax community
what are the two sides of a sand dune known as and where does deposition occur
-leeward (deposition)
-windward
type of coast that sand dunes form on
-low energy coastal plainsq
conditions of waves for sand dunes
constructive waves
prevailing onshore winds blow sand inland
what allows pioneering species to colonise dune
-rotting seaweed brought in by storm
