Ecological succession occurs in this scenario because the area is changing again to its original or starting stage due to change in its environmental conditions. Those plants that needs large amount of water will vanished and those plants that needs less water will take the place of that plants. This phenomenon also occur with other animals that living in that ecosystem.
Gnetophytes are gymnosperms
, they are woody and the embryo has two cotyledons
. Cycads are woody plants that produce seeds found in Subtropical and warm temperate regions and also they produce motile sperm cells.