Who knew there are so many ecologists?
Theoretical Ecologists, Population Ecologists, Behavioural Ecologists, Landscape Ecologists, Marine Ecologists, Restoration Ecologists, Soil Ecologists, Ecosystem Ecologists, Evolutionary Ecologists, Community Ecologists
Community Ecologists focus on the interactions between species within a community and how these interactions shape the structure and function of the community. Interest in this group started to wane in the mid 1990s and spawned Conservationist and Invasion Ecologists.
Conservation Ecologists work to understand and address the impacts of human activities on nature (biodiversity) and ecosystem health, with a focus on preserving species and habitats. Invasion Ecologists study the negative impacts of invasive species on nature, ecosystem health, and human well-being.
The newest group is the Urban Ecologists who study the interactions between living organisms and their urban environments.
In today’s fast-moving world the work these ecologists do is important. At our human pace we don’t notice the planetary changes our modern living brings about. Their studies and theories help us understand and direct our better selves. Each of them is interconnected.
But it seems to me that it is the Conservation and Invasion Ecologists who are the outliers, especially with the Evolutionary Ecologists. Sadly, I believe, it is only the Conservation and Invasion theories that have captured the attention of many home gardeners. I speculate this is due to their alarming message (that non native species are bad and native species are good) being sold to lay people in simple terms via popular media and mass-marketed books. But, the ecology that touches gardeners most is not simple. In fact, it is complex. Nature (biodiversity) is complicated, ever-evolving – fraught with challenges, upheavals and extinctions – but I believe novel ecologies brought about by the movement of non native plants will be nature’s best chance.(1)
It was Daniel Janzen (Janzen 1980) who first coined the phrase, “ecological fitting”. That is where an introduced plant coexists with its new neighbours without causing mayhem. It is also in these novel ecosystems that new species are being formed, adding positively to biodiversity. There is no denying that co-evolution happened but it is now long-accepted that it is not the default explanation for every relationship between species.(2).
A common conservationist and nativist touchstone is the butterfly. Ponder then; even though the Black Swallowtail has lost a large amount of its former territory due to land development it has managed to survive due to the prevalence of non native Queen Ann’s lace, and is now the main host for its caterpillars. The Clouded Sulphur, Wild Indigo Duskywing and the Silvery Blue, all lay eggs on their non native adopted hosts, cow vetch and crown vetch. The Painted Lady prefers Canada thistle as its host plant. These native butterflies are all common in Toronto but they did not co-evolve with their adopted host plants.(3) (The Monarch in California is breeding on non native milkweed (4)) These are examples of “ecological fitting” and a rejection of the older, inflexible theories that co-evolution is the predominant driver of biodiversity.
Some of the modern ecologists whose work supports ecological fitting and novel ecosystems are worthy of review;
Professor Chris Thomas, York University, says, “it is time to rethink our irrational dislike of invading species”. He believes hybridization involving introduced plants is happening fast.(5)
Professor Arthur Weiss, Toronto University, studies indicate that plant speciation will accelerate with climate change(6)
Professor Mark Davis, Macalester College in St. Paul, is a leading critic of the idea that there is something unfit about non native species. “Nativeness is not a sign of evolutionary fitness or of a species having positive effects. The insect currently suspected to be killing more trees than any other in North America is the native mountain pine beetle Dendroc-tonus ponderosae.”(7)
Peter Kareiva, chief scientist of The Nature Conservancy in the USA, the world’s largest and richest environmental organization, says conservationists have “grossly overstated the fragility of nature, arguing that once an ecosystem is altered, it is gone forever.” “The trouble for conservation is that the data simply do not support the idea of a fragile nature at risk of collapse.”(8)
Discussion
As Master Gardeners we have always been inclusive of all gardeners. For example, I take no issue with a gardener who wishes to plant only natives, but I fail to see the science that it is an imperative. Likewise, those who believe native plants should be protected (conserved) should be allowed to do so. It may seem to me to be futile, requiring huge inputs of time, labour and resources, but there should be freedom to do so. What do you believe is the compelling scientific research that mandates Master Gardeners to be conservation activists? As educated horticulturalists should we not be embracing all scientific research and a wider, unbiased, approach to plants in home gardens?
(1) https://phys.org/news/2024-06-native-animals-ranges-faster-species.html
(2) https://www.researchgate.net/profile/Daniel-Janzen-2/publication/248428625_When_is_it_co-evolution/links/5559301f08ae6943a876b6d9/When-is-it-co-evolution.pdf
(3) https://www.toronto.ca/wp-content/uploads/2017/08/969e-Biodiversity_ButterfliesBook-Division-Planning-And-Development.pdf
(4) https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=46009
(5) https://www.nature.com/articles/502007a
(6) https://e360.yale.edu/features/first_comes_global_warming_then_an_evolutionary_explosion
(7) https://www.researchgate.net/publication/51202855_Don’t_judge_species_on_their_origins
(8) https://thebreakthrough.org/journal/issue-2/conservation-in-the-anthropocene
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