Which of the following is true of ecological succession? pioneer organisms move into new communities first. primary productivity decreases as succession proceeds. secondary succession takes place within new communities with no previous soil. all of the above are true. which of the following is true of ecological succession? pioneer organisms move into new communities first. primary productivity decreases as succession proceeds. secondary succession takes place within new communities with no previous soil. all of the above are true. which of the following is true of ecological succession? pioneer organisms move into new communities first. primary productivity decreases as succession proceeds. secondary succession takes place within new communities with no previous soil. all of the above are true.