Stevie Nicks, Naturalized Species, and the future of the biosphere

Art Shapiro is no stranger to the long-time readers of Million Trees.  Professor Shapiro is Distinguished Professor of Ecology and Evolution at UC Davis, and a renowned expert on the butterflies of California.  He is the author of a seminal, frequently cited study of California butterflies that reported the results of 30 years of observing butterflies in his research transects. (1)  He summarized this study in his Field Guide to the Butterflies of the San Francisco and Sacramento Valley Regions:

“California butterflies, for better or worse are heavily invested in the anthropic landscape [altered by humans].  About a third of all California butterfly species have been recorded either ovipositing [laying eggs] or feeding on nonnative plants.  Roughly half of the Central Valley and inland Bay Area fauna is now using nonnative host plants heavily or even exclusively.  Our urban and suburban multivoltine [multiple generations in one year] butterfly fauna is basically dependent on ‘weeds.’  We have one species, the Gulf Fritillary that can exist here only on introduced hosts.  Perhaps the commonest urban butterfly in San Francisco and the East Bay, the Red Admiral is overwhelmingly dependent on an exotic host, pellitory. And that’s the way it is.”

 Professor Shapiro has given us permission to reprint his Amazon review of the most recently published critique of invasion biology, Inheritors of the Earth, by Professor Chris Thomas (University of York, United Kingdom).  We recommend Professor Thomas’s book to our readers.  Although it is learned, it is accessible to the general public.  This book is another step forward in the long march to acceptance of the reality of existing landscapes that are adapted to present climate conditions.

 Million Trees

2011 Chris Thomas published a paper in the journal “Trends in Ecology and Evolution” entitled “Translocation of species, climate change, and the end of trying to recreate past ecological communities.” I immediately e-mailed him (April 11, 2011): “I have been delivering the same message in my advanced courses in Community Ecology and Biogeography for years, and have found the students by-and-large highly receptive, especially when they have internalized the overwhelming evidence for wild fluctuations in climate and vegetation since the end of the Ice Age 10-20,000 years ago. But over and over I have been told ‘but of course that is not the Party line…restoration ecology,’ blah, blah….Thank you for giving me a respectable citation, since merely citing one’s self can never do.” He e-mailed back: “…the conservation community in Britain seems mainly to be treating me with bewildered patience! I think that it will take time for everyone to become re-programmed to accept change as a reality.”

But of course change is not only a reality, it is the norm in ecology. Belief in equilibrium states and a “balance of nature” has been a dogma without a rationale beyond sentimentalism for many decades. There are coevolved segments of communities that are intimately synchronized and interdependent (say, figs and fig wasps or yuccas and their moth pollinators), but a great deal of any community is the product not of coevolution but of what Dan Janzen calls “ecological fitting,” whereby things haphazardly thrown together by the vicissitudes of geology, climate or commerce just happen to click. We are surrounded all over the globe by functioning communities and ecosystems with little to no history in geologic time. For about 40 years I have asked my students on their final exam how one might go about telling the difference between coevolved communities and “communities” assembled by chance. It is an exceedingly difficult question.

So this book is an expansion of the TREE [Trends in Ecology and Evolution] paper, and its message is vital. Resources for conservation are limited, and one must prioritize. The vast majority of naturalized alien species are harmless and many may be potentially beneficial. The ones that are genuinely harmful should be fought tooth and nail, but of course we do that anyway–we call it “pest management” and “public health.” The blanket indictment of “invasive species” makes no more sense than the blanket condemnation of human immigrants. Of course, when we say this, Thomas and I and Fred Pearce and “that Marris woman!” are immediately called out as shills for the extractive industries or the nursery industry or the Bilderbergers or the Zelosophists (conspiracy theory villains!!) or some despicable cartel of nature-haters. Pure poppycock. Truth-tellers attract trolls. That’s just the way it is.

Quite a few years ago a group of us took a prominent visiting British ecologist (not Thomas) on a field trip to the Sierra Nevada. We had half a dozen grad students and a few faculty crammed in a van. On the way up, one of the students sort-of apologized for the predominance of naturalized alien plant species in the lower foothill landscape. Our guest demurred forcefully: “Why must you consider this some kind of tragedy? Why don’t you see it as an opportunity for all kinds of evolutionary novelty to arise?” Indeed.
Thomas asks (p. 104): “How long will it be before the environmental police force of ecologists and conservationists is prepared to step back and decriminalize introduced species that have had the temerity to be successful?” An excellent question.

Stevie Nicks got over her fear of change: “Time makes you bolder…children get older…I’m getting older too.” Maybe conservationists can mature after all.

Arthur Shapiro

Professor Thomas’s book is very much in the mainstream.  The Economist magazine included it in their list of important books published in 2017.  It is one of only a few books in the category of “Science and technology” and it is at the top of the list.  The Economist says of the book, “Humans have consigned species to extinction at an alarming rate.  But hybridization and speciation is happening quickly too.  An ecologist at the University of York shows how humans are bringing about a great new age of biological diversity.  Extinctions ain’t what they used to be.”

The New York Times published a review of “Inheritors…” on New Year’s Eve.  The reviewer summarizes Thomas’s main argument: “He argues that new species are arriving and evolving faster than old species are dying out globally…Instead of the sixth extinction, it’s a sixth genesis.”  The reviewer faults Thomas for not portraying the “wonder of nature” and for giving oceans short shrift.  But, the reviewer concludes with this observation about the unhelpful role that humans often play in conservation efforts: “It is human concerns that determine everything here on Earth now.  An animal that arrived in a particular location hundreds or thousands of years ago is fine with us, while a more recent immigrant, like garlic mustard, is cause for alarm and extensive campaigns to extirpate the interloper.  Nostalgia is deadly, as people kill to preserve or restore some ill-remembered but more natural past, and we disdain new species as weeds.”  That observation about human attempts to control nature says it all.  Plants and animals are not to blame for the damage we are doing to satisfy our ideological commitment to the distant past. They are symptoms of change, not the cause of change.

Happy New Year!

Million Trees

Update:  Professor Thomas gave a presentation to the Long Now Foundation in San Francisco on June 19, 2018.  HERE is a video of the introduction to his presentation.
And HERE is a presentation at the National Academy of Sciences, “Moving Times for the World’s Biodiversity.” If you haven’t read his book, his presentation is a good summary of the issues he covers in his book.  MT

1. Arthur M. Shapiro, “Exotics as host plants of the California butterfly fauna,” Biological Conservation,110, 413-433, 2003