Climate Corner: Why biodiversity matters

Sep 25, 2021

Randi Pokladnik

While I was researching my masters thesis in 1998 on organic farming in Ohio, I came across a disturbing event in Jack Dole’s book, “Altered Harvest: Agriculture, Genetics and the Fate of the World’s Food Supply.”

In 1970-71, the USA lost over 15 percent of its corn crop. “In the late summer and early fall of 1969, a few corn fields in southern Iowa began behaving erratically. Ears rotted inside husks and stalks fell to the ground.” Soon the blight, which was found to be a fungus (Helminthosporium maydis) or Southern Corn Leaf Blight, began moving across corn fields from Florida to the Midwest. Unusually high humidity aided the spread of the fungus spores.

The fungus was able to reproduce within a few days of landing on corn, and in ten days a new generation formed. It was resilient and could survive temperatures of twenty degrees below zero. It rapidly moved into northern states and eventually into Canada. Some farmers lost 50 percent of their corn.

The underlying cause of this agricultural disaster was blamed on the type of corn grown. Over 80 percent of the corn in the USA contained T-cytoplasm and this particular hybrid was extremely susceptible to the blight.

The National Academy of Sciences said, “because of a quirk in technology, the redesigned corn plants of America had become as alike as identical twins. Whatever made one plant susceptible made them all susceptible.” Heirloom varieties of corn survived the fungus but the majority of America’s corn were hybrids from “six inbreed lines.”

Monocultures, or raising only one variety of crop on large acreages of land, whether it is corn or pine trees, leaves the species vulnerable. It also reduces biodiversity. A healthy biodiverse forest can be habitat for many different birds, plants, insects and animals. A monoculture is not a healthy ecosystem. It allows for some insect species to grow out of control or a single predator or disease to wreak havoc in a short period of time. This was the case with the corn crops.

Biodiversity matters more than most people realize. Our world is becoming less biodiverse; species populations are declining at an alarming rate, and entire species are becoming extinct. The journal Science reported that in the past five decades, bird populations have dropped 29 percent: a loss of three billion individuals.

In 2020, thousands of dead birds were found in the southwest USA. The event remains a mystery to scientists, but the American Birding Association cites some factors that might have caused the massive fatalities. In Albuquerque, N.M., on Sept. 8, 2020 the temperatures dropped from a sunny high of 96 to a record low of forty and experienced a windstorm with speeds of 70 mph. During the same week, Colorado, Montana and parts of New Mexico experienced a snowfall and record-breaking low temperatures.

Adding to the plight of migrating birds are the massive fires that continue to burn in the Western States. The birds were forced to leave the region before they had a chance to “replenish their fat stores.” Many areas adjacent to the fires saw a major influx of migratory birds over the past two weeks.

Starvation is another factor. All of the above weather events killed the insects these birds rely on in order to fatten up for the long journey south. Birds whose diets consist heavily of insects, like swallows and warblers, saw the highest rates of mortality. These incidents are all tied to climate change.

Biodiversity is also affected by habitat loss, overexploitation, and invasive species. Habitat loss is pervasive over the entire planet. We see this as the forests of the world are logged and land is converted from natural landscapes to urban uses. Additionally, habitats are degraded and fragmented. We see this in our own region with oil and gas development, logging, and farming.

Fracking requires a huge amount of infrastructure with roads, well pads, and pipelines eating away acreage. There are enormous water withdraws, which affect wetland ecosystems. Large fracking operations use evaporation pits containing toxins to reduce waste volumes. These pits are often mistaken by birds looking for bodies of water. The US Fish and Wildlife Service estimated 500,000 to 1 million birds are killed annually in oil pits and evaporation ponds. Also, birds are often burned to death by gas flares as they fly over gas and oil infrastructure.

A prime example of overexploitation occurs in our oceans. The now multi-million-dollar high-tech fishing industry allows fish to be taken from deeper depths and from every location in the ocean. The United Nations Food and Agricultural Organization said, “over 70 percent of the world’s fisheries are overexploited and significantly depleted due to overfishing.”

Invasive species have wreaked havoc on native species. Losing elm trees to the invasive fungus Ceratocystis ulmi, and chestnuts to the fungus Cryphonectria, caused a dramatic change in the structure of eastern forests and a loss of biodiversity. More recently, the USA is being invaded by the “spotted lanternfly.” These bugs came to us from Asia and can cause serious damage to trees, eventually resulting in death. The bug affects many species including grapes, apples, and hops as well as hardwoods.

However, the biggest contributor to a massive loss of biodiversity are the changes on our planet caused by climate change. Inside Climate News reported that “biodiversity is declining faster than at any time in human history and a million species are on the brink.” In order to avoid the collapse of entire ecosystems we need to rapidly reduce our greenhouse gas emissions. The flora and fauna of our planet simply cannot adapt to the current rate of climate change.

What are humans losing as we lose biodiversity? We will lose the ecosystem services like flood mitigation, crop pollination, cures for diseases, soil formation, nutrient recycling, pests and pollution control, and regulation of the climate. Most of these services are not valued on the New York Stock Exchange but make no mistake, the economic effects will be felt globally, especially within the food sector.

How can we help? As we near the end of the growing season, leave the garden and flower cleanup till spring to allow a shelter for insects and other organisms. Grab those seed catalogs and plan for a pollinator garden next year, one that use native species rather than non-native. Support nature preserves and government decisions that protect natural habitats, like the Endangered Species Act. Stay alert for invasive species like the Spotted Lanternfly. Reduce your carbon footprint.

Teach others that we share our planet with millions of other species and our existence depends on their existence.


Randi Pokladnik, Ph.D., of Uhrichsville, is a retired research chemist who volunteers with Mid Ohio Valley Climate Action. She has a doctorate degree in Environmental Studies and is certified in Hazardous Materials Regulations.