Hydrosere

• • When an area of freshwater is created it is usually quickly colonised by single celled algae from the soil
  • Birds such as herons and ducks and flying insects such as water beetles and pond skaters can bring in spores and seeds of algae, diatoms and plants
  • The lake edges start to be colonised by rooting plants such as reeds, lillies and reedmace
  • However the open water may be too deep for such plants so only floating plants live there
  • The more the area is colonised by plants the more food and shelter there is so more animals that arrive can survive
• • As plants grow and die, the lake gradually fills in with dead organic matter as well as soil and sediments carried in from the surrounding area
  • As the water becomes shallower conditions continually change until rooted plants can survive
  • Emergent plants that have their leaves above the water shade the submerged plants which gradually die out
• • As sediment fills the lake and open water recedes, aquatic species progressively disappear
  • As soil accumulates and develops to the extent that it can support the weight of much bigger plants, trees that can survive in waterlogged soil such as willow and alder start to colonise the area
• • As transpiration by trees removes water and more sediments accumulate the soil becomes drier
  • Trees such as oak will be able to colonise
  • These larger trees create a denser canopy, providing shade which inhibits the growth of smaller plants
• • Eventually the community is dominated by the largest trees with other plants and animals living in,on or under them
  • Few of the original species involved in the early stages of the ecosystems development are still present