Seed Dispersal Methods

The seed is the result of sexual reproduction in plants. The ovules contained in the flower are fertilized by pollen grains. And voilà! This creates a seed that contains and protects a plant embryo.

The seed is a future individual in dormancy. Depending on the species, it can spend several weeks, months, or even years waiting for favorable conditions to germinate.

To ensure their dispersal and the perpetuation of their species, plants have developed different strategies. Some use wind, others gravity, water, or even animals. Each dispersal method has a very specific ecological name. We wanted to introduce them to you!

Anemochory

Seeds transported by wind are generally small and light. They often possess adaptations such as wings, pappus, or hairs that allow them to glide. Examples include ash samaras or maple samaras, the dandelion achene, or the winged capsular seed of the linden tree. You know, those helicopters we try to catch mid-flight!

With the first gust of wind, the seeds fly several tens or even hundreds of meters!

Zoochory

Animals can disperse seeds passively: when seeds have specific mechanisms to attach to fur, plumage, or are appetizing (in the form of a fleshy fruit) to be transported by the animal inside its digestive system. For example, foxes and martens consume these fleshy fruits.

Dispersal can also occur actively! For example, Eurasian jays are birds that sort and store oak acorns to create reserves for the winter season. The jay thus contributes to the reforestation of forests because not all of them are found by the animal: it can disseminate nearly 6,000 per year.

With this type of dispersal, seeds can end up up to 1.5 km from the mother tree!

Anthropochory

Zoochory, but with Humans as the vector. Humans also transport seeds, voluntarily or not.

Through agricultural activities, trade, clothing, vehicles, or even sowing, they largely contribute to the dispersal of plant species.

Example of plants propagated by armies: l’ambroisie à feuilles d’armoise: Massively introduced into Europe via troop movements and horse fodder during world conflicts.

Unfortunately, this can also contribute to the emergence of invasive alien species, as our mobility is not the same as in Neanderthal times. But this is another debate.

Hydrochory

As its name suggests, hydrochory represents dispersal by water or rain. Water can be a means of transport, as for the seeds of the yellow iris, the willow, or even coconuts in a more tropical biome. Rain can also be the trigger for seed germination in many moss and fern species.

Autochory

Seeds are dispersed by a mechanism that the species creates itself, generally mechanical auto-ejection. Des Pods ou des husks se forment et dry out tellement qu’elles en burst au moindre friction et se dispersent sur un perimeter relativement close de la plante-mère. Le broom disperse ses graines de cette façon.

Barochory

Here, no intermediary.

Barochory is a mode of seed dispersal by gravity, in which seeds, sometimes carried in heavy fruits, fall directly to the ground, near the mother plant. The oak acorns are the most striking example.

These strategies promote reaching environments conducive to the germination of seeds, whose conditions are specific to each species. This dispersal ranges from the base of the mother plant to several kilometers away. The further away, the more the species minimizes competition between young shoots.

And let’s not forget: the seed ensures the perpetuation of the plant, its longevity, by containing its genetic heritage.

Did you know?

A simple hedgerow brings together species using several dispersal strategies: wind, birds, mammals, water… By restoring hedges, we are not just planting trees: we are also recreating the conditions that allow plants to spread naturally and strengthen ecological continuities.