Curious Nature: How the wind, animals water, and fire spread seeds
Walking Mountains Science Center
Have you ever walked outside on a windy day and seen seeds flying through the air? Or picked a dandelion and blew on it and watched the fluffy seeds blow away? These are both examples of how wind helps to disperse seeds.
Because plants are not mobile, they need help to spread their seeds and reproduce. Seeds can be dispersed by animals, water, and even fire. In some plants, seeds are contained within a fruit, which when eaten by animals are dispersed through defecation.
The invasive houndstongue found throughout the Rocky Mountain area has seeds with little hooks on them that can get stuck on the furry coat of animals passing by, while others will float on a body of water such as a creek or river until they land in a suitable spot. Whatever the method, these interactions with their environment are essential and effective in helping them to reproduce and survive from year to year.
Sitting by the creek on a breezy June day, what I thought was snow started falling all around me. I thought to myself, “Could this be snow? It looks like snow but it’s not cold out!”
And then I remembered that it was simply the creative cottonwood trees along the creek bed dispersing their plentiful seeds. The wind is almost everywhere, which makes it a great dispersal method for plants. Even a slight breeze can help carry seeds from one place to another which increases the chances of seeds such as those from the willow landing in a place suitable for growth.
Seeds that are dispersed by wind have adapted to be better suited to float in the air. For example, plants like willows and cottonwood trees have seeds with light, feathery bristles that can be carried in the wind. Trees such as maples, elms, and ashes have “winged” seeds called samaras that don’t float like a feather but flutter and spin to the ground like a helicopter. Mountain mahogany shrubs create an especially creative way to fly. The stigma from the flower remains attached to the seed, forming a fuzzy “tail” that lifts it in strong wind gusts.
Because there is no limit to how far wind can travel, the longer the seed can stay in the air, the further it will go. In fact, a cottonwood seed can travel up to 5 miles from its mother tree in the right conditions.
This is important because if plants grow too close together they will compete for sun, water, nutrients in the soil and lack the genetic diversity needed to withstand disease. Wind helps the plants spread out so they have room to grow without fighting with other plants in the area.
Without competition, these plants are able to grow strong enough to disperse their seeds and continue the reproduction of their species. The disadvantage, however, is that the plant has no control over where its seeds land, so a large majority of seeds won’t ever grow. This is why plants must devote so much energy to producing seeds. A single dandelion flower produces about 200 seeds.
Oftentimes, plants will just seem to pop up in places without being planted. This could be due to seeds blowing in on a strong breeze and being dropped on fertile soil. The next time you go outside, keep your eyes open for seeds flying through the air. You may be surprised just how many plants you find that use the wind in their pursuit for survival.
Dominique Rosario is a Summer Naturalist at Walking Mountains Science Center and loves hiking and finding new favorite restaurants in the Eagle Valley area.
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