While wildlife extinction is a natural phenomenon, scientists report that the current rate is abnormal. Normally, extinction happens at a rate of 1 to 5 species every year. However, our planet is currently losing species 1,000 to 10,000 times faster than the normal rate. Over the last 500 years, as many as one thousand species have vanished, and this doesn't even account for the thousands more that went extinct before scientists discovered and described them.
Previous studies show that today’s extinction is far different from past ones. Extinctions used to be caused by catastrophic natural phenomena like volcanic eruptions, asteroid strikes, and violent climate changes. However, the current crisis is caused almost entirely by humans. Experts report that as many as 99% of the species at the threshold of extinction are there due to human activities. In recent years, we have seen reports of certain species being critically endangered such as the koalas and fireflies. This time, bumblebees are now under threat.
Facts About Bumblebees
Bumblebees are different from honey bees as their colonies are not perennial in nature. They don’t store a surplus of honey that can be harvested. These species contribute immeasurably as pollinators of wildflowers and crops, which is also beneficial to birds and small mammals as they rely on food for this. Scott Black, Executive Director of The Xerces Society, stated that 85% of the world’s flowering plants depend upon pollinators to reproduce, which makes them an essential link in Earth’s ecology.
According to Food Tank, a non-profit organization focused on building a global community for safe, healthy, nourished eaters, bumblebees and other native pollinators are vital to crop pollination as more than two-thirds of the world’s crop species rely on them. The fruits, seeds, and livestock feed produced by pollinators provide over 30% of the food that we consume. However, the ecological service of pollination is being placed at risk by extensive and ongoing loss, alteration, and fragmentation of habitats.
Bumblebees are also an effective alternative to labor-intensive manual pollination of greenhouse-grown tomatoes, sweet peppers, and strawberries. This is why they are reared commercially for shipment to growers, especially for greenhouse-grown crops. At the same time, these species have longer tongue and wing vibrating tendencies, making them more efficient pollinators for some plant species. However, just like other species, bumblebees have been listed as endangered, vulnerable, or near threatened by the International Union for Conservation of Nature and Natural Resource's Red List of Threatened Species.
Declining Bumblebee Population
Thomas Wood, an entomology postdoctoral researcher at Michigan State University, stated that bumblebees support the seeds and berries that birds and other animals depend on through pollination. They are proven effective pollinators of many fruits and vegetables that are important for people’s healthy diet. However, a 2019 study revealed that half of the species studied have seen a more than 50% decline.
According to the World Economic Forum, an independent international organization committed to improving the state of the world by engaging business, political, academic, and other leaders of society to shape global, regional, and industry agendas, researchers found out that some species declined while some remained stable. They investigated the kinds of plants each bumblebee species visits to find some patterns. The team then removed pollen from the specimens and identified them under a microscope.
“Species that declined collected pollen from fewer species of plants and seem to have a narrower range of plants they visit for pollen. In contrast, the stable species visit a much wider variety of plants. This suggests that picky eaters are less able to switch if a favorite plant isn’t available,” lead author Wood said.
The researchers also compared the distribution of 12 different bumblebee species across Michigan’s 83 counties before and after the year 2000. The study published in journal Ecology revealed that some of the biggest declines include the Rusty patched bumblebee (100%), American bumblebee (98%), Yellow banded bumblebee (71%), and Yellow bumblebee (65%). However, the researchers also found that the common eastern bumblebee and the brown belted bumblebee have increased by 31% and 10%, respectively.
Bumblebees Face Mass Extinction
Rampant pesticide use and habitat loss have been the main causes of the rapid decline of bumblebee populations. A recent study conducted by the researchers from the University of Ottawa revealed that the increasing global temperatures are also heavily affecting the species. The team looked at 66 different bumblebee species across two continents. They discovered that bumblebee populations have declined by 46% in North America and by 17% in Europe.
"The scale of this decline is really worrying. This group of organisms is such a critical pollinator in wild landscapes and agricultural regions,” Peter Soroye, a doctoral student in biology at the University of Ottawa and lead author of the study, said.
According to Carbon Brief, a UK-based website designed to improve the understanding of climate change, the decline of bumblebee populations matches closely with the “frequency and extent to which climate conditions approach or exceed species’ observed climate limits.” These species are heavily affected because they prefer cooler, slightly wet temperatures. Thus, they are unlikely to survive in areas prone to heatwaves, prolonged dryness, or frequent extreme weather.
The researchers used a complex modeling system to look at bee populations and to find the reason for their decline, where they concluded that bee populations suffered the largest decline in places that have warmed at a faster rate than the rest of the planet. They created the model using a database of roughly 550,000 bee records over a century. The team also studied two time periods: 1901 to 1974 and 2000 to 2015 and examined if temperatures and precipitation exceeded the bumblebees' tolerance level.
According to The Guardian, a British daily newspaper, the researchers were able to see how bumblebee populations have changed over the years. “We were surprised by how much climate change has already caused bumblebee declines. Our findings suggest that much larger declines are likely if climate change accelerates in the coming years, showing that we need substantial efforts to reduce climate change if we are to preserve bumblebee diversity,” Dr. Tim Newbold of University College London’s Center for Biodiversity and Environment Research said.
This only shows that even the tiniest species living on our planet can be directly affected by climate change and global warming. If this continues, there’s a high possibility that more and more species will face mass extinction.