CONDON’S CORNER
[Published February 24, 2025, by The Daily Progress, the daily newspaper of Charlottesville, Virginia, and The News Virginian, the daily newspaper of Waynesboro, Virginia. Published by The Daily News-Record, the daily newspaper of Harrisonburg, Virginia, on March 10, 2025.]
On June 8, 2011, the journal Nature published a commentary by 19 ecologists who urged conservationists to “assess organisms on environmental impact rather than on whether they are natives”.
https://www.nature.com/articles/474153a
“Classifying biota [the plants and animals of a region] according to their adherence to cultural standards of belonging, citizenship, fair play and morality does not advance our understanding of ecology [the relations of organisms to one another and to their physical surroundings]. Over the past few decades, this perspective has led many conservation and restoration efforts down paths that make little ecological or economic sense”.
This other side to the story regarding alien species—in particular, nonnative “invasive” plants—is rarely publicized, yet it should be. It’s been fourteen years since this essay appeared and was ignored by virtually everyone. As a result, the general public, government at every level, scientists, the media, and especially environmental groups and the people that support them have currently instituted a scorched-earth policy that’s bringing about much destruction of viable habitat and the poisoning of our environment via herbicides.
Many people now fervently believe that so-called invasive alien plants pose a dire threat to native insects, undoubtedly due to the 2007 book by entomologist Doug Tallamy, Bringing Nature Home, which they often cite. In it, he wrote that “scientists who know what they are talking about” developed “an extensive body of theory” that predicts that native plant-eating insects “should be able to eat only vegetation from plants with which they share an evolutionary history”.
This assertion, which holds that herbivorous insects eat only those plants they have co-evolved with under the same environmental circumstances, sounds logical to the uninitiated. However, it disintegrates under scrutiny.
Dr. Tallamy tells us these 6-legged critters that feed upon plant tissues are limited to feeding upon “no more than a few plant lineages [a single line of genetic descent through time]”, thus making them “specialists”. However, each plant lineage can include hundreds, if not thousands, of species around the world—which means an insect is likely to be able to feed upon at least some of the plants that are related genetically, regardless of their country of origin.
Indeed, gardeners and butterfly enthusiasts know full well that the Monarch butterfly can feed on milkweeds that are not native to their region. The Showy Milkweed (Asclepias speciosa) is often planted in eastern gardens and considered native because it grows in the United States, but it's actually only native to the western half of North America. If President Thomas Jefferson hadn't made the Louisiana Purchase in 1803, the central area of our country might still be owned by France, in which case no one would dare call this milkweed "native". Obviously, then, geo-political boundaries do not determine whether a plant is native to your location.
We know that countries share plant lineages (and even some species), so it should be expected that phytophagous (herbivorous) insects should be able to eat vegetation from other areas on the Earth, and, indeed, they do (in contrast to Professor Tallamy’s “extensive body of theory” to the contrary).
In Bringing Nature Home, Doug Tallamy recounts the plight of native Eastern Tent caterpillars (Malacosoma americanum) that ran out of cherry leaves on a tree too small to feed them adequately. He mentions that leaves were still available to the caterpillars in the form of a Japanese Honeysuckle vine (Lonicera japonica) that had climbed the little tree, but he points out that the caterpillars “had not taken a single bite out of the alien plant…even in the face of starvation”.
The duplicity embedded in this tale is the subtle suggestion that the caterpillars would have eaten the honeysuckle if only it had been native, as he never points out that the caterpillars would have faced starvation even in the presence of a native vine if—like the alien honeysuckle—it wasn’t a member of the Rose Family (as is this caterpillar’s preferred native host plant, the cherry).
I have documented tent caterpillars feeding on a relative of the cherry—the nonnative, unevolved with, and much despised Multiflora Rose (Rosa multiflora) growing at the base of a leaf-stripped Black Cherry tree (Prunus serotina). A factuality is that you can find native insects feeding upon nonnative plants, but, of course, you need to look!
.jpg)
.jpg) |
| A native Eastern Tent caterpillar feeding upon an alien Multiflora Rose shrub in Albemarle County, Virginia, disproves Doug Tallamy’s contention that native plant-eating insects “should be able to eat only vegetation from plants with which they share an evolutionary history”. |
People have been manipulated into believing alien plants serve no ecological purposes when, in fact, they very much do, in very many ways, for innumerable insect (and other) species. As the 19 ecologists wrote in their paper, “[A] valuable step would be for scientists and professionals in conservation to convey to the public that many alien species are useful”, and that “Natural resource agencies and organization should base their management plans on sound empirical evidence and not on unfounded claims of harm caused by nonnatives.”
Amen.
No comments:
Post a Comment