Updated: Sep 2
Plants, trees and vegetation are immobilized and anchored by roots. Unlike animals, plants and trees can't "get up and go" and physically travel to other regions. Because of this, Mother Nature has developed creative methods to help ensure the healthy continuity of plant and tree species. Seeds help to fill this gap in movement by dispersing to more favorable environments. Overcrowding isn’t sustainable and dispersing seeds farther away from the parent plant (to sites where more suitable conditions exist) can reduce conspecific competition for water, sunlight, nutrients, and space.
The dispersal of seeds can change the number of plants in a given community allowing different plant species to move and colonize new habitats. There are a variety of different types of seed dispersal methods which help to spread the plant species to other communities. Different Types of Seed Dispersal Gravity: Where the seeds simply fall to the ground, like apples, black locust tree seed pods, common mullein and teasel seeds.
Animals: Wildlife will help to spread seeds, like forgotten walnuts and acorns previously stored for winter. Birds also eat the fruit of plants such as wild grape, Virginia creeper, European buckthorn and staghorn sumac, which disperses seeds in their droppings after digestion.
Hitch Hiking: Some plants have also developed fur and feather hitch-hiking adaptations like hooks, barbs and spines, displayed by species such as common burdock, devil’s beggar-tick and enchanter’s nightshade.
Dehiscence: Ballistic seed dispersal is another adaptation to release seeds through explosive dehiscence; a noteworthy example is the common jewelweed which rapidly releases a seed when touched. Garlic mustard silique and common milkweed follicles also undergo dehiscence and open at seed maturity, though milkweed also develops white hairs that allow for wind dispersal as well.
Wind: Other species with wind capabilities are sow thistle, Canada goldenrod, and maple and ash samara. Common cattail also disperses well in the wind and in the water.
Lastly, humans play a large role in seed dispersal, with many activities like farming, gardening, recreation, and transportation causing widespread deliberate and accidental introductions and cultivations.
Different types of seed dispersal
1) Gravity – Seed falls to the ground;
2) Animal and wildlife seed dispersal;
3) Fur and feather hitch hiking adaptations such as hooks, barbs spines;
4) Ballistic seed dispersal that releases seeds through explosive dehiscence;
5) Wind seed dispersal;
6) Human seed dispersal through activities such as farming, gardening, recreation, and transportation