Many of us grew up with childhood memories that included chasing and catching fireflies if you lived in northern latitudes and click beetles if you lived along the Gulf Coast. Collecting them, placing them in jars, and proudly showing them to our parents and friends, we all marveled at the critters’ iridescent green glow. Young people likely have rarely seen fireflies, certainly not in the numbers we once enjoyed. What happened to them?
Of course, no one thing nor individual group is responsible for the decline in insect numbers. Impacting all native wildlife throughout North America, the causes have been going on in insidious fashion throughout our history. However, during the past one-hundred years our impact is nearing an ecological tipping point. This tipping point may result in the collapse of food chains for animals, including the human food chain. Among the historical culprits are clearing forests for logging and stripping land for agriculture. These changes, while necessary, result in agriculture monocultures, the introduction of alien species, and overall reduction of native plants. During the past 75 years, we have added massive urbanization, highways, and streets. Collectively, these obstacles have contributed to the fragmentation of the environment to such a degree that the energy flow of the “Earth System” has changed. This disruptive change has led to the demise of insect fauna that provides the protein needs of all the animals.
Insect fauna comprises 72% of the terrestrial Earth biomass. We have abandoned the agrarian to embrace the urban, and as a result, we have decimated insect populations. We buy our food from HEB rather than harvest from a backyard garden. We landscape our yards with plants that serve little environmental purpose. The Judeo-Christian belief that all of the Earth’s bounty is provided for our personal greed is a false assumption perpetrated and encouraged by early religious storytellers.
We have responsibility for the stewardship of our property. The good news, we who caused the problem are key to fixing it. The following paragraphs will address the cause and effect relationships of native plant loss and the decline of wildlife and present ways to ameliorate the problem of these environmental changes. Fragmentation is that process whereby tracks of land have been repurposed to human use rather than Nature use to the extent of disrupting migration, population mixing, and mating access all of which reduce species diversification. Only in recent years are conservation groups trying to purchase large tracks of land to help restore native habitat and create linkage from Canada to Central America and beyond. This monumental effort will take generations of commitment and an enormous expenditure of money. Destroying habitat that took millions of years to create is cheap, restoration is expensive.
Our Plymouth Rock Mayflower settlers brought with them alien species of plants, and so the onslaught began and has been continuous. By promoting alien plants as viable landscape choices, modern nurseries are part of the problem. Examine your yard or patio plants if you live in an apartment. Do you see insect damage? If not, you likely are hosting alien plants. Not knowing the plant leaf’s chemical makeup, a native insect will not recognize it as food. The plant originated on another continent where it did have predators but here it has none. On the surface, this sounds wonderful.
Decorative flowers, beautiful yards of turfgrass, trees planted by the builder, all in keeping with neighborhood association requirements, may possess curb appeal but produce few insects. What most of us have is a sterile yard, more plastic-like than real. Multiply this scenario by millions of homes and commercial establishments and one sees that the loss of the storied “firefly” is an example of the demise of insect populations.
So, why is this bad? “I don’t like bugs when I’m in my yard,” you may say. The problem is that these “bugs” are fundamental to the ecology of the planet. Insects do not live in isolation. The relationship between insects and native plants goes back to nearly 500 million years. They co-evolved while traveling evolutionary pathways that predators and prey follow, adapting, and re-adapting while keeping sensitive equilibrium. While all plants produce primary metabolism (the production of oxygen gas and glucose through photosynthesis), it is within the leaf’s leaves whereby secondary metabolites fight the evolutionary battle of creating protective chemicals, pollination enticements through structure and savory treats to reward plant helpers. In order to answer the question at the beginning of this article, we all must understand that mass sterilization of the earth is decimating the ecosystems. As the insect populations collapse, vertebrate populations soon follow, and we are doomed to the same fate.
Today’s pandemic provides a valuable lesson. Viral diseases like COVID-19 jump from host to host in order to survive; this time the virus jumped to us. This in itself is not unusual. It is part of evolution. What is unusual is that no human has ever had this particular coronavirus; therefore, the entire human population is susceptible since we have developed no antibodies in our bodies to combat this virus. Humans have been the coronavirus that has devastated the world’s insect populations. As we kill off other species of animals by intent or negligence, we make ourselves more vulnerable. We decrease animal populations by killing the insect food source. In the case of insects and other Arthropods, we kill them off by removing native plants, genetically modifying food crop cultivars, and by applying massive pesticide applications. These actions break down the energy flow from plants to animals including vertebrates.
Let us look at the impact of insects on a chosen species of vertebrate, the bird. We go bird watching or birding. Birding is the most common outdoor activity of people worldwide, generating hundreds of billions of dollars. Birding revenues generate more economic impact than all athletic enterprises combined. We understand that habitat loss, fragmentation, automobiles, and buildings and other structures have a huge impact on the decline of bird populations. Ninety-seven percent of terrestrial bird species use insects to feed their young. Sorry everyone, baby birds do not eat seed, milk, bread, or even Whataburger. They eat protein from insects and other Arthropods. With all the obstacles mankind has placed before bird survival, we now systematically starve their progeny. When science researchers speak of habitat loss, they are not describing real estate allocation or neighborhoods for birds, but the loss of native places that grow native insects that feed the next generation of birds. These insects require native plants for sustenance. It is the insect that moves energy from the plant to the animals more highly evolved.
As negligent as humans have been toward the cornucopia of living things provided to us, thankfully many people are realizing that unless we make a determined effort to preserve native species, the human race will suffer the fate of the insect and experience a drastic decline in population. What would happen if everyone growing plants in a pot or in their yard would replace them with native plants? Your neighbors may be of the mindset that “a plant is a plant.” There is some myth that a nursery plant is more beautiful than the native. Remember that the nursery’s alien plant you think is so pretty is likely a “weed” where it originates and bears secondary metabolites unfamiliar to native insect populations. If over a few years each of us replace our sterile yards with productive yards of predominantly native plants, the insects would return, and bird populations would rebound in most places.
Urban centers easily can become part of the nature corridor for animal migration, for native plant restoration, and as a result, the bird population increases. Every yard should replace turf grass with native grasses and forbs. Yards should be modified. Removing turf grass and adding an understory of bushes around our trees grass will prevent tree damage. Hedgerows of alien plants can be hedgerows of native plants. Replacing alien plants with native plants will restore native insects. Guess what? Your neighbors will never know the difference in your plants but will recognize the differences in the insects they see, notably the butterflies. You will be modeling for your neighbors and neighborhood. Are you going to have insects that annoy you? Yes. Are your children and grandchildren going to see fireflies and click beetles? Absolutely. Will this happen overnight? No. Ten years appears to be the time it takes to begin seeing large changes in these conversions. If native plants are reestablished, increase populations of insects will follow, and our grandchildren will enjoy the green glow of the firefly.
This article first appeared in the Corpus Christi Caller-Times on July 26, 2020.
Chad Huckabee, South Texas Master Naturalist