I’ve been meaning to read ‘Bringing Nature Home’ by Douglas Tallamy for a while. American readers will probably heard of it – the book which makes the case for growing native plants to support biodiversity, and something of a bible for ‘nativists’. Who, I gather are gaining strength in the US. Whenever I visit I hear complaints from gardeners about “native nazis” – people who dogmatically assert that anyone growing non-natives is somehow an enemy of the environment. It seems a tragedy that an important debate has gotten so bad-tempered.
Tallamy’s book certainly makes the case for North American gardeners to grow natives to support the food web for American wildlife, basically because most herbivorous insects feed only on very specific native food plants. That is a very different matter from saying that they should grow ONLY natives. Which Tallamy does not actually say, but he rather implies it. Like many nativists he implies too strongly that non-native = invasive alien, whereas any gardener can tell you that only a small proportion of garden exotics have leapt the garden fence to become smotherers and chokers of native habitats. The book is certainly a very useful resource for anyone wanting to know what to plant to attract what insect species – which of course then go on to support birdlife. So, I’d certainly recommend American readers to get it.
BUT, take it with a pinch of salt. Like any scientist who supports a cause, the polemic can overwhelm the science. I cannot imagine that the author’s reputation as a scientist is helped by the crude graphs in an appendix at the back showing proportions of insects supported by alien and native species – there is no indication of what the plant species are! This part of the book is a travesty of what presenting scientific data to the public is about.
The other day I had lunch with Ken Thompson, of Sheffield University’s Animal and Plant Sciences department. Ken is very involved with a series of projects going under the titles BUGS. Which look at garden biodiversity and how best to support it. The evidence here (in the UK) is that there is little relationship between the amount of native flora in a garden and the animal life it supports. The important thing is to have some trees and lots of diverse habitat: shrubs, climbers, perennials, little creepy ground-covery things down below, physical connections between different groups of plants, lots of different plants packed in together – a slightly messy plant-collectors garden in other words. Probably like the average KapliPRO reader’s garden. We discuss how the British flora is a rather sorry one, what we have is what managed to get over from the European continent after the last ice age, before we became an island. Ken tells me that not only is our flora very generalist but our insects too – so British herbivorous insects here are not too fussy about what they eat. North American biodiversity is much greater – especially of plants, which support a greater number of specialist insects, species whose larvae will only eat particular (native) species. So the situation here is undeniably different.
Ken hadn’t read ‘Bringing Nature Home’ but was familiar with Tallamy’s work. Which he was clearly a bit sceptical of. The word “spinning” was even used. The problem he explained was that Tallamy was like many ecologists – they don’t do much research in gardens, and tend to focus on native insect species, disregarding alien insects – and insect-eating birds and bats are not particularly fussy about whether it’s native or exotic insects they eat.
It all comes down to what insect larvae eat. They are the fussy ones. Nectar-sucking insects are not fussy. “No contest” says Ken, “when it comes to gardens being heaven on earth” for adult insects such as bees, hover flies, butterflies etc. which live on nectar. A BRITISH garden I should point out (see below for my rude remarks about American gardens). I also asked him about honey bees, as a friend in Vienna (a bee expert) suggested to me once that the current obsession with falling bee numbers which is leading to so many more people keeping honeybees, might be bad news for native species of bee – too much competition. “No” says Ken, “flowers keep on producing nectar as bees take it, so that’s not a problem”. Good, one less eco-thing to worry about.
Time to get back to gardens. Now look dear American readers, KapliPRO readers will I am sure have gardens a bit like most British gardens, full of plants, perhaps a bit untidy. I don’t need to tell you that most American gardens and managed landscapes are like deserts – all those acres of grass shaved to within an inch of its life, a few trees if you are lucky and some evergreen shrubs. And they tend to be big. Wildlife value = zilch.
The message to me is clear. There is plenty of room in the average American garden to grow lots of natives to support lots of native specialist insects and keep the food web going, but there is also plenty of space to grow lots of non-natives too. A good multi-cultural garden in other words. No need to feel guilty about growing non-natives, and every reason to stand up to bossy dogmatic nativists.
On to my final point. It’s an issue that I know makes African-heritage gardeners uncomfortable. There aren’t too many prominent Black or Asian people in British gardening (or in US gardening either for that matter). Banging on about native plants and invasive aliens has always made me, and quite a few other commentators uneasy – there are some unpleasantly racist undertones here. Anyone heard of Willy Lange? German landscape architect and garden writer? Very keen on native plants and extermination of alien species from German gardens? Got the Adolf Hitler Award for services to Nordic landscaping in, I believe, 1935?
I hear the sound of marching men. Which I do not like.
I am now tweeting on @noelk57 and don’t forget my own blog on: http://noels-garden.blogspot.com, where I have a piece on the lost garden of Hadspen House.