The Wild Side: Insects impacted by climate change, pollution
I worked in southwest Minnesota for five years before returning to my home state of Wisconsin. One reason I left that area was my increasing sensitivity and reaction to chemicals sprayed on crop fields from planes to kill insects. These neurotoxin chemicals disrupted the food chain and even had direct impact to organisms (like me) that inhaled the mist or touched the material lying on the plants and the ground. While these chemicals kill harmful insects, they also kill any pollinators working to make the soybean plants bear fruit. The group of pollinators, or creatures that help fertilize flowering plants as part of their feeding activity, is in dire straits around the world. In my final wildlife doomsday installment, we will look at the global loss of pollinators.
The simple bumble bee, for example, is in alarming decline across the country. Here in the U.S., four common species of bumble bees have declined 96 percent in recent decades. Other bees are also crashing, as are butterflies, moths, wasps and bats. Chemicals have played a large role in their decline, making it extremely difficult to adjust to other factors like climate change. Some of the changes brought about by the changing climate, like an earlier spring or longer growing season, might not be too harmful or may even be helpful to some insects. Other changes, like invasive plants, competing invasive insects and an increase in diseases can all be linked to a moderation in climate.
The honey bee is suffering from a mysterious colony collapse disorder, which killed one of every three colonies starting around 2004. Honey bees also fall prey to a bloodsucking parasite called the varroa mite, which carries a virus deadly to the bees. Another species of honeybee, the Africanized honey bee (or killer bee) has moved north from South and Central America into parts of the southwestern U.S. They effectively take over resident honeybee hives by killing the queen and replacing her or by mating with her and displacing the former honeybee strain. It’s tough being a bee right now.
More than three-quarters of the world’s flowering plants need help with pollination from insects, birds or mammals. They pollinate more than 180,000 different plant species, including more than 1,000 crops. This means that much of the food we eat is impacted by the reduction in pollinators. The almonds grown in California are one example. For the last several years, farmers have had to truck in honey bee hives to pollinate their trees. The hives then must be moved to a different location or the bees will starve, because with only one kind of food in a large area for a brief period, the insects cannot sustain themselves. Naturally, the loss of beehives not only impacts foods like fruits, nuts, legumes and grains, but the loss of honey itself. To learn more about the current worldwide decline of pollinators, check out the website pollinator.org.
There are topics we haven’t covered in this series, like melting ice caps, rising sea levels and changes in wildfire regimes. This was just a glimpse into some examples of wildlife declines and links to climate change across the continent and around the world. How will these doomsday scenarios play out? Are we really going to lose insects, trees and native wildlife in the next half- century? There are predictions that cover the widest range, from stating little is going to change to stating the planet will be unlivable. The changes we have already documented are themselves the source of debate; some scientists claim the changes are strictly natural swings as part of a climate shift cycle, and others state that human expansion and development are to blame or have at least exaggerated the changes we are experiencing. Whatever the cause and whatever the product, change appears inevitable. We will have to learn as we go to make adjustments for ourselves, and to do what we can for wildlife.
Jeremy Holtz is a wildlife biologist with the Wisconsin DNR in Rhinelander and writes a weekly column in the Star Journal. To contact him, call (715) 365-8999.