They have special adaptations that enble them to survive on dry and nutrient poor soil.Pioneer species are hardly plants which usually have dense root systems to bind the sand particles and hold water and humus.they have  a short life cycle.When they die,their remains add to the hummus content of the soil.Hence,the pioneer species modify the environment,eventually creating conditions which are less favourable to themselves.Instead they establesh conditions that are more condusive to other species which are called successor  spesies.

                              Pioneer species at mangrove swamp have special adaptations that enable them to survive on dry and nutrient-poor soil.Pioneer species are hardly plants which usually have dense root systems to bind the sand particles and hold water and humus.They have  a short life cycle.When thet die,their remains add to the humus content of the soil.Hence,the pioneer species modify the environment,eventually cerating condotions which are less favourable to themselves,Instead, they establesh conditions that are more condusive to other species which are called successor species.Examaples of successor species at mangrove swamps are Rhizophora sp and Brugeira sp.

                

colonisation

Colonisation takes places in newly formerd areas where no life previously existed.  For example, very fews spscies can survivel in an environment of sand and stones since it stores little water and has few available nutrients.  The first colonisation are called pioneer spesies

Variation

Two types of variation:
1.continuos variation
2.discontinuous variation