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  • Writer's pictureIsaac yelchin

Ballistic Seed Invasion

Careful and thoughtful plant selection is vitally important when constructing a garden or planting anything around your house. Invasive species can take over an ecosystem rapidly and be detrimental to biodiversity. It may seem that having a small plant in your enclosed garden won't be an issue. However, plants have many different methods of seed dispersal that can spread their offspring far and wide without you noticing. Some plants may stick a bur into your pants as you walk past. Then the seeds in the bur will get deposited at the local park when you go for a picnic. Or a seed pod filled with hundreds of seeds can get picked up by a small gust of wind and fly for miles. It isn’t the plants fault, they are just trying to survive. We must be cautious and not give the opportunity to these plants.

You may be asking yourself, what's the big deal with invasive species, how do they lower biodiversity, aren’t you adding a new species, shouldn’t that be an increase in biodiversity? Invasive plants come from different parts of the world with different animals, parasites, and bacteria. The predators, parasites, and diseases, for those plants may not be transported with the invasive, so then the plant has no natural enemies in the new area it has invaded. They may be from harsher, drier climates, and thrive when exposed to the wetter soil. If you have a few native plants fighting for space, sun, water, and against predators, then a plant with none of these pressures will easily outcompete the natives. Once it does this, whole swaths of land can be rendered unlivable.

Take this huge area of dead mustard photographed above and below. Mustard is invasive, and outcompeted all the native plants to an extent that it covered almost every inch of the ground. Not only did it outcompete everything, but then all the mustard died. The dead stalks aren’t going to move on their own and have taken all the space away from any native plants. So not only did the invasive take over this area and create a monoculture, but they themselves died. Now this area is now almost completely void of life. Not even the mustard is living there! The dead grey stalks covering most of this landscape is the mustard. In this space of 60 plus acres you can see how few living native plants are able to squeeze into the mustard graveyard.

A terrible offender is Castor Bean. This plant is from east Africa and made its way to the United States long ago. There are no natural predators to this plant, so it grows fast and big completely unhindered. It then produces thousands of seeds, which are highly poisonous containing ricin. So unsuspecting animals may be killed if they sample a seed. This poison protects the seeds and allows them to germinate without any fear of predation. Young Castor Bean pictured below.

The dispersal method of Castor Beans is known as the ballistic method. This is what it sounds like, the seed pods will dry out and then constrict. This creates pressure that ultimately leads to an explosion, shooting the seeds out 20 feet on average. Take a look at the fresh and dried seed pods below. These seeds can lie dormant and viable for 2-3 years. So once a Castor Bean plant has matured and produces seeds, it is almost impossible to stop its spread.

Yet even with all this being common knowledge, the plant is still made readily available at garden stores and online. You can buy one without receiving any of these warnings. You can potentially destroy a neighboring native ecosystem without having the slightest idea. It is a shame because this is completely avoidable. You can have a Castor Bean in your garden as long as you carefully trim any seed pods before they become pollinated, then there is nothing to worry about.

The world is full of unknowns, and you cannot always have the answer before you try something. In fact not all invasive species are bad. The honeybee, or rather I should say the European honeybee is an invasive species to America, however it does its job pollinating. On top of this, the worst invasive species to exist in the history of the world is You and I. Don’t take that too hard, really all I ask is to take care when adding to your garden and do a little research.

Isaac Yelchin is foremost a herpetologist. He studies lizards, frogs, newts, and the like. Specifically, he spends all day and night thinking about what it is like to be an animal. What are the animals thinking about? What is their perspective? When he should be working, he sits and stares at his pet lizard asking himself these questions.

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