EarthTalk® | December 2020

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Our inability to notice or care about the plants around us could pose an existential threat to humanity. Credit: Francesca Zama, Pexels.

Dear EarthTalk: What on Earth is “plant blindness?” — Betsy Carlucci. New York, NY

Botanists James Wandersee and Elizabeth Schussler coined the term “plant blindness” in 1998 to describe “the inability to see or notice the plants in one’s own environment, leading to the inability to recognize the importance of plants in the biosphere and in human affairs.” An additional aspect of plant blindness is the “inability to appreciate the aesthetic and unique biological features” of plants and “the misguided, anthropocentric ranking of plants as inferior to animals, leading to the erroneous conclusion that they are unworthy of human consideration.”

Wandersee and Schussler coined the term after years of discussion back and forth about a fundamental problem: if we don’t pay attention to plants and their role in supporting the rest of the lives on the planet including our own, how will we ever agree on the need to conserve them, much less support plant science research and education? Also, letting plants die out poses an existential threat to humanity and the rest of life on the Earth. Researchers believe one in eight plant species around the globe are threatened with extinction as our (plant-dependent) human population continues to swell.

What causes plant blindness? According to Wandersee and Schussler, social and educational biases are definitely a big factor, with so-called “zoo-chauvinistic” educators at all levels tending to use animal (instead of plant) examples to teach basic biological concepts in the classroom, lab or field.

Of course, there is likely more to it than educational biases. Wandersee and Schussler argue in an article in Plant Science Bulletin that another major contributor to plant blindness is the nature of the human visual information-processing system, in that our brains can’t possibly process everything around us immediately just because our eyes are open, and we are hard-wired to prioritize certain visual cues (like movement that may signal an animal threat) over others.

One study they cite concludes that over the course of a single second, the eyes generate more than 10 million bits of data for visual processing, but the brain can only extract 40 bits during this timeframe and can only fully process 16 of them that reach our conscious attention. Another study found that participants more accurately detected images of animals than plants in an “attentional blink” study designed to test people’s ability to notice one or two rapid-fire images. And yet another study found that children recognize that animals are living creatures before they can tell plants are also alive, and that they remember images of animals much better than images of plants.

To Wandersee and Schussler, devoting more of our educational resources to teaching kids and adults about plants and their role in supporting life is the key to overcoming plant blindness. Indeed, seeing the plants all around us could be key to our survival on the planet, so it behooves each and every one of us to learn more about the environment around us and start appreciating not just the other fauna we share life with but also the flora that helps make it all possible.

Contacts: Plant Blindness, academic.oup.com/bioscience/article/53/10/926/254897; “Toward a Theory of Plant Blindness,” www.botany.org/bsa/psb/2001/psb47-1.pdf; “Plant blindness and the implications for plant conservation,” conbio.onlinelibrary.wiley.com/doi/pdf/10.1111/cobi.12738.


PPE waste is a big environmental concern now given we are discarding hundreds of billions of disposable masks & gloves every month globally. Credit: Kaspars Misins, Pexels.

Dear EarthTalk: What’s the environmental impact of all the single-use PPE we are throwing away now in huge numbers as a result of responding to the COVID-19 crisis? — Jay M., Cary, NC

There’s no question about it: all the disposable Personal Protective Equipment (PPE) in our waste stream is taking a toll on the environment. A recent study in the journal Environmental Science & Technology found that we are using some 129 billion disposable masks and 65 billion disposable gloves every month around the world nowadays as we try to stay safe in the midst of the worst pandemic to hit the human race in a century.

Most of the masks in the U.S. are made out of polypropylene-based plastic but some are made from related forms of plastic such as polystyrene, polycarbonate, polyethylene or polyester. These synthetic fibers are designed to resist liquids and do not biodegrade in the environment once discarded, instead breaking down into smaller and smaller pieces of plastic that end up in landfills or, even worse, as litter that finds its way into waterways and the ocean.

Some of the discarded PPE ends up in medical waste bins and is shipped off to an incinerator for disposal, which unfortunately may not be any better for our health or the environment. According to the U.S. Environmental Protection Agency (EPA), incinerators send particulate matter, heavy metals, acid gases, nitrogen oxides, carbon monoxide and other noxious pollutants airborne. As such, environmental advocates aren’t happy about a plan by the United Nations to help communities around the world set up their own small local incinerators to deal with PPE and other COVID-related waste.

Meanwhile, reusable masks may have a longer life as a useful product, but that doesn’t mean they’ll necessarily biodegrade in the environment when their time comes. Most are made from cheap synthetic fabrics like nylon or polyester and are prone to breakage and short lifespans, and can last even longer and wreak more havoc when littered into the environment.

The upshot of all this is that we’ll have discarded PPE from the pandemic around for a lot longer than we would like. It joins the rotting plastic that sits in landfills, washes up on beaches and floats in oceans, amounting to more than five trillion plastic particles contaminating the world’s surface waters. The particles are toxic to ecosystems and wildlife. Marine creatures can mistake mask remnants and fibers for food, and/or can get entangled in them so they can’t hunt, feed or eat.

So what can we do to offset, or even halt the impact? The pandemic continues, but by choosing reusable, biodegradable masks, we can reduce the demand and consumption of PPE. Eco-friendly alternatives are available — or you can make your own using salvaged fabric and online craft guides. The Hemp Foundation and Tentree sell masks made from biodegradable and repurposed materials. Meanwhile, Bambooo’s bamboo masks are made out of sustainably sourced, pesticide-free bamboo, and Planet Organics’ cotton/rubber varieties are also attractive and easy on the environment.


Contacts: “COVID-19 Pandemic Repercussions on the Use and Management of Plastics,” pubs.acs.org/doi/pdf/10.1021/acs.est.0c02178; “COVID-19: Unmasking the Environmental Impact,” earth.org/covid-19-unmasking-the-environmental-impact/; “Health experts call for reusable PPE to protect people and planet,” greenpeace.org/international/press-release/44356/health-experts-reusable-ppe-protect-people-planet/; Hemp Foundation, hempfoundation.net; Tentree, tentree.com; Planet Organic, planetorganic.com; Bambooo, Bambooo.com.


The polar bears of Alaska’s arctic are already threeatened by global warming but now they may have to contend with oil drilling apparatus in one of the most ecologically sensitive and important parts of their habitat. Credit: Cheryl Strahl, FlickrCC.

Dear EarthTalk: Where I live in Southeast Michigan, an invasive insect called the Emerald Ash Borer is wreaking havoc on our forests. Are other parts of the country dealing with this pest or others that are killing large numbers of trees? — John D., Sterling Heights, MI

In a growing number of U.S. states, residents have been dealing with a different kind of quarantine that began back in the early 2000s and continues on today. But this one involves wood, not people, and the perpetrator is a beetle, not a virus.

The problem started in 2002 when the Emerald ash borer, an exotic green beetle that probably hitched a ride to the U.S. with wood materials from Asia, began decimating ash forests in Michigan. Since then, this little invader has killed hundreds of millions of ash trees across 35 U.S. states and five Canadian provinces. Ecosystems where these ash trees play a pivotal role are decimated, while forest products industries and property owners in these areas are also worse off. And wood coming out of affected regions is being quarantined to make sure it isn’t harboring the invasive pest before being shipped out to other parts of the country or world.

While the Emerald ash borer is found almost exclusively on ash trees, several other invasive bugs are also plaguing other types of forests across the continent. Asian long-horned beetles, Spotted lanternflies, Banded elm bark beetles, Brown spruce long-horned beetles, Common pine shoot beetles and European oak bark beetles are just a few of the bugs preying on our native forests.

A new Asian gypsy moth strain is another emerging threat to U.S. coastal forests. The U.S. Department of Agriculture (USDA) warns, “If established in the United States, Asian gypsy moths could cause serious, widespread damage to our country’s landscape and natural resources.” In May 2020, Washington governor Jay Inslee issued an emergency order in response to the infestation. These moths have wrought havoc before, and scientists have offset infestations using a special kind of moss on different East Coast strains. Hopefully similar measures are that a measure can counteract impacts on the West coast soon, as well.

There are many factors driving the spread and growth of harmful species to trees in North America. Clothing imported from China, wood brought from Canada, sugar transported from Brazil, and much else of what we consume here that comes from abroad brings with it the transport of species, whether on purpose or by accident, with potentially catastrophic effects.

Climate change is also a factor. Insects live in specific environments based on weather, and their ranges expand and breeding seasons increase as global temperatures rise. Mountain pine beetle numbers, for example, have grown rapidly in recent decades due to the warming climate. Cold winters that usually drive beetles to hibernate, protecting pine forests for a spell, are growing shorter. Beetles can now complete two reproductive cycles in the expanded warm seasons, leading to increased tree mortality in affected regions. If warming continues at the current rate, trees won’t be able to adapt fast enough to survive.

There’s not much individuals can do to prevent the spread of invasive tree pests except by buying wood products produced by local logging operations or wood lots. Likewise, procure firewood from local sources, as many pests hitchhike into new terrain on firewood in back of the family station wagon.

Contacts: USDA Emerald Ash Borer Info, invasivespeciesinfo.gov/terrestrial/invertebrates/emerald-ash-borer; DontMoveFirewood.org, DontMoveFirewood.org.

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