Human impact on the biosphere is so massive that it triggered a new geological age, the Anthropocene. So far, we have difficulties understand the extent of the influence we have on our planet. A recent study demonstrated how artificial light is a serious threat to plant pollination. It puts plant reproduction in danger, as well as the whole ecosystem.
A team of researchers at the Institute of Ecology and Evolution from the University of Bern has recently published a study on this issue. The Swiss team, led by Dr. Eva Knop, investigated how artificial light at night disrupts pollination.
Pollination happens when pollen gets transferred to the female reproductive organs of a plant. It enables fertilization. In many instances, this process depends on pollinators. These are animals - like wasps, flies, bees and hummingbirds - that move pollen from the male reproductive organs of flowers (anther) to the female (stigma).
Plants and animals have co-evolved for millions of years, perfecting this system. They formed symbiotic communities that depend on each other to survive and thrive. That is, of course, until a new species came into play, often bringing disruption and change.
Pollinators are declining worldwide, and anthropogenic (human caused) factors are to blame. These factors include intensive agricultural practices, the introduction of invasive alien species, not to mention climate change. Humans are putting in jeopardy the essential service that pollinators provide to plants, both crops or wild. As if that wasn't enough, the Swiss team has now added another factor: artificial lighting.
The researches found that "in artificially illuminated plant-pollinator communities, nocturnal visits to plants were reduced by 62% compared to dark areas", as stated in their study. This means that nightly visits from bees, flies and other pollinators decreased because of artificial human light.
We still don't know the extent of the negative impact of artificial lights on our ecosystem.
Despite receiving daytime visits from pollinators, the nocturnal lights were enough to reduce the fruit output of a single plant by 13%. Furthermore, the negative effects also propagate to daytime. This worsens the decline of pollinating networks. The impact of this decline is unknown, but it has the potential to cause serious problems to our biosphere since plants are at the basis of most ecosystems in the planet.
One of the paper cited sources states that "light pollution is the alteration of night natural lighting levels caused by anthropogenic sources of light". As the studies demonstrate, this often overlooked form of pollution has severe consequences for terrestrial ecosystems. The rapid global increase of artificial lights at night does not seem to be stopping anytime soon. Artificial sky glow impacts areas that are hundreds of kilometers away from the original light source. Even protected areas, such as the light domes of Las Vegas and Los Angeles, can be seen from the Death Valley National Park, situated nearly 200 km away.
Our planet at night, glowing with human lights.
This phenomenon is widespread, as the source states: "The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans". The impact of light is often overlooked and studies like the one conducted at Bern University may help us start "shedding light" on this issue.
Seems like this is another conflict between Technosphere and Biosphere. As human systems evolve, they must also deal with biological systems. Hopefully in the future we can improve their coexistence, as we move further and further into our next nature.
Sources: Nature, Science Advances