Some Deeper Thoughts on What Makes an Endangered Species

     Recent news items about preservation of endangered species regularly raise questions about exactly what a species is and how it differs from other similar less-threatened relatives.  For example, the eastern red wolf is only maintained under controlled breeding with a very limited wild colony or two – maintained by testing all pups and destroying those with traces of coyote genes.  Now, the New York Times had a piece on the large-scale destruction of a barred owl population in the northwest to save another species.  We all remember the great hullabaloo about saving the spotted owl by preserving the last fragments of that owl’s habitat in old-growth redwood forests.  Now, human habitat manipulation has created a corridor of woodland across the great plains to allow the eastern barred owl to expand its range into Washington and Oregon.        

     We remember from biology 101 that two similar species are distinct when they are unable to produce fertile offspring after mating. That can happen through genetic incompatibility, or just because they live on separate continents.  Spotted and barred owls look a bit different (spots versus bars), but only range separation kept them from interbreeding. 

    As barred owls have spread across the grassland barrier, their much larger population is expected to swamp the spotted owl genome.  The last resort is to manually cull the barred owls from the area of potential contact.  I had wondered how the wildlife staff required to go out and kill red wolf puppies that tested as genetically impure could face their children at night when questioned about what they did at work that day.  Now we have the specter of ornithologists massacring an owl we have learned to love here in the Ozarks.  Imagine what those Pacific northwest loggers will have to say about that. 

     This brings us back to the basic question of what exactly a species is and how did we get to our current definition.  If you investigate the history of taxonomy to figure that out, you run into a complex web of events that involve religious controversies about the accuracy of Genesis, the existence of evolution as a natural force, the apportionment of credit to the pioneers of taxonomy, and the political correctness of nomenclature. 

Fortunately, you don’t have to descend into that complicated historical jungle on your own.  Jason Roberts has just now (April 2024) published an eminently readable account of the complicated twists and turns along the path on which we came to describe the species that inhabit our earth: Every Living Thing – The Great and Deadly Race to Know All Life.   As a working scientist, I remember worshipping at the carefully groomed botanical shrine once maintained by the great Carl Linnaeus while attending a conference at the University of Upsala in Sweden.  Roberts shows that a whole lot more of the scientific community was involved in the development of Linnean taxonomy that we learn in biology class than just a precocious Swede proposing an effective way of ordering all life on earth.  

     Carl Linnaeas became a prominent Swedish medical professor in the 1740’s when medicinal plants were a major part of existing treatments.  Earlier naming systems for botanical components of the medicine cabinet had seemed too cumbersome, so he designed a rational system based on the sexual character of flowers such as the number of stamens or petals.  Some thought that even referring to sex was scandalously licentious.  This approach worked as it turns out that reproductive features are one of the dominant aspects that identify most plants.  But a published version of the scheme extended to animals and minerals.  Many experts found this just too simple to be effective.  Chief among these was Georges de Buffon, director of Louis XIV’s royal garden in Paris.  He was publishing his own encyclopedia of all life on earth, finding the Linnaean system totally inadequate because only a carefully distilled set of characteristics could be used to classify, for example, the mammalian world.  Behind this controversy were the conflicting beliefs about creation: were there a limited number of creatures such as could fit on the Ark, or was there a much greater number in existence that had been further proliferated by evolution?  Could the discovery of a few fossilized creatures that had possibly gone extinct be just the remains of those that didn’t make it onto the Ark?  In subsequent years, scientists continued to work the taxonomy field from both ends.  Some mentored by Buffon worked to streamline the list of defining features, while disciples of Linnaeas expanded and revised the original twenty-six (conveniently consistent with alphabetical representation) to improve accuracy.  Most importantly, they settled on the genus and species nomenclature we use today, and Buffon’s successors followed suit. 

     By the time of Buffon’s death in 1787, his approach seemed to be winning out as more creatures such as the kangaroo and platypus were discovered by expanding exploration.  Then the French Revolution turned the world upside down.  Buffon’s grave was desecrated, and the Jacobin crowd decided the “simplified” Linnaean system was the epitome of rational science on a par with the new decimal calendar system.  Citizen Carl had his image enshrined in the Pantheon, while ignoring his conspicuous wealth and ennobled position in his home country.  After Waterloo, a wealthy British merchant purchased the entire Linnaean set of papers and specimens from his impoverished widow, where they were enshrined in the British Museum.  Carl’s body was even named the official type specimen for Homo sapiens in the Linnaean system.  Membership in Linnaean societies such as those in Paris and London proliferated.  Buffon’s emphasis on using words from native languages such as Baobab for an iconic African tree were sometimes still honored, and the Linnaean precept that nomenclature be based on the first published reference became the rule.   According to Roberts, the original five-level hierarchy of classification from kingdom down to species has been elaborated to 21 levels.  Linnaeas gets the credit, but the taxonomy we know today was a complicated process of technical distillation with several seemingly arbitrary steps involved.

     All of this suggests that when we consider protecting endangered species we should be just as concerned with the species part of the designation as the technical aspects of endangerment.  A big factor here is the Anthropocene.  The environmental/ecological background against which we evaluate the level of endangerment needs to be considered.  We have seen the appearance of the wolf-coyote hybrid as a consequence of reducing the vast forests of the Appalachians to a mosaic of fields, pasture, secondary growth woodlot, suburban development and expressway medians.  Studies show that these environments are ideally suited for the omnivorous ways of the coyote instead of the strictly carnivorous wolf.  Ecologists now refer to the theory of punctuated equilibria in evolution, where species hold constant until a sudden change in environment forces drastic re-ordering of alleles.  Perhaps as punctuation perpetrators, we should revise how we think about species in our efforts to preserve the natural world.