Nonnative phobia

My English insects love New England daisies

Cathi regular sends me emails with links to scientific research she thinks will interest me. I immediately replied about a recent one telling her that my hackles had risen. She replied “yes I know”. Based on a single piece of research Washington DC citizens were being urged by their local masters to plant native plants in their gardens; the missive implied nonnatives were the work of the devil.

I was reminded of when Mike and Isobel bought an acre of a neglected farm field attached to their garden. Quite reasonably they had to apply to the local authority for change of use. In this case to make a naturalistic wildlife area as a garden extension. 

They got their permission with the proviso that they only plant natives. I know if they transgressed just a smidgeon someone would report them.There were no restrictions on the original farmer!

US gift to UK

Europe's gift to America

The thrust of my piece today is why I consider such thinking is wrong and such sanctions are based on narrow and sometimes low quality research, intensely publicised propaganda by zealots and lack of promotion of facts that do not point the same way.

Readers will know my own predisposition is to let plants and animals of the world intermingle. Particularly in view of climate change we need all the good genes we can get. I know there are problems with invasive species and it is not my intention today to challenge worthwhile (but sometimes misguided) national attempts  to control movement of weeds, pest and disease.

This US nativer and UK nonnative grows wild in Wales

My motive is merely to tell gardeners to carry on spreading  diversity by planting in their gardens from a pallet of plants of the world that have already been established and made the UK (or wherever you maybe) their home. I find it quite ironic that our American friends regard our UK wild flowers as aliens and we do the same for their own. I might add determining whether a plant is nonnative or not is not easy!

Whilst my hackles were still high I read a wonderful piece on the Botany One website reviewing a book about the detailed thirty year record of her small Midlands garden lovingly kept by professional entomologist and lifetime ecologist Jennifer Owen. She recorded every living thing she could find using her professional skills and knowledge and the equipment of her university colleagues. She has precisely identified nearly 3000 plants, animals, insects and other invertebrates. Others have suggested this indicates perhaps a total of 8000 had she had all the time in the world. The diversity of plant and animal life per unit area she recorded was greater than any in such as the Amazon jungle. She is gracious enough to observe that as many of our gardens are so similar this diversity is somewhat repeated but as Cathi remarked last night the jungle is pretty repetitive too. Sadly her record shows a decline in diversity in recent years.

Her review makes no distinction between natives and none natives and nor would they be discernible or of consequence.

I wonder if we should resist planting horse chestnut as it has only resided in the UK for four hundred years

The very next day I clicked onto the excellent Garden Professors blog. They too had taken exception to the Washington research and were also quoting a similar project that comes to precisely the opposite conclusion

Both investigations focusses on a single (but different) chickadee species. These birds have a limited diet and specialist skills in locating and extracting leaf miners. Leaf miners have a fairly limited host range and this in itself negates the relevance of the effect of a single bird species to draw any overall conclusion damning all nonnative plants.

The Washington research by the way claims to show that if aliens provide more than 30% of the biomass of the garden the chickadee population declines.

The other piece of research published a year earlier was specifically how a different chickadee species had adjusted to a new alien plant Lonicera maackii which was now a valuable resource

The thing is that the flawed research had 37,000 google hits after two days, the earlier research a mere 196.

The difference was the advance publicity by the vested interest promoting themselves and pushing a preconceived doctrine

Several things make me uncomfortable about this much publicised trial

1. I am sure that the PHD student who was leader of the project was conscientious and able and had ample expert supervision but really….

2. The trial was quite small

3. I suspect unconscious bias. The gardens were partly self selected on the basis of volunteers in a community group - all birders with a specialist interest. 

4. One lady who had moved into a new house already planted with a lot of alien plants was told at the beginning that it was a perfect illustration of what not to do! 

5. I fear that the researchers and gardeners had a vested interest and prior expectation.

6. If most of the gardens were owned by bird lovers would there be consequential disproportionate bird feeding?

7. Similarly would gardens with a high proportion of aliens be owned by a different king of people, perhaps tidier, more prone to plant garden centre plants, use more pesticides and so on - I just don’t know but these things make a difference

8. The real crux is that the research was based on a single bird species with a rather specialised diet and yet huge leaps are made in its general significance

9. High quality research considers the work of others - no mention whatsoever is made of contradictory results elsewhere.

What happens in this world is that politicians with little knowledge latch on to a popular mantra and go along with it

US native Dicentra cucullaria is almost extinct in the wild but persists in our gardens

What I have discussed today revolves around planting native species to host native organisms. (Some we might regard as pest and disease). What I think much more important is to plant alien plants to conserve them. Many plants from worldwide sources only exist in our gardens. Their native habitats have been destroyed

I have written in a previous post how no native plant has been lost in the UK as a result of planting aliens -  although of course some have been lost by habitat destruction.

This Himalayan wild flower causes a bit of a stir in the UK but our native bees love them.

Since writing this piece I came across this research suggesting newly introduced plants may fair better with climate change than native plants or already established aliens….But is this good or bad?

I understand some of my relatives cause a bit of a stir in London parks

Links

What raised my hackles

The Garden Professors joined the debate

Jennifer's book is a little expensive but you can read about it here

I wrote about none natives before