And now there’s scientific evidence that proves it.
A recent study in Australia has shown that mistletoes are essential for maintaining biodiversity in native Australian forests. One third of bird species vanished when mistletoe was absent and, since those birds were largely insectivorous species, the value of the mistletoe lies not just in berries and nesting habitat but also in the number of insects directly or indirectly supported.
The research took place over five years and involved physical removal of mistletoe in 17 sites ranging from 5 to 25 hectares. There were also 23 control sites either with undisturbed mistletoe or with a natural absence of mistletoe. For full details check out the Royal Society Proceedings or the summaries at ABC Science or in a recent Economist write-up.
This study is, of course, not about our native European mistletoe, and indeed as there are over 90 mistletoe species in Australia higher diversity is to be expected there. But our own single mistletoe species does have similarities – with a distinct assemblege of obligate insects and a handful of birds that specialise in the berries. This value is recognised in Europe and in the UK, where mistletoe’s biodiversity contribution to old orchards is often quoted. More obscure and indirect biodiversity benefits, such as those arising from the differing leaf litter etc implied in the Australian study, have not been assessed in Europe – perhaps they should be…
But any study needs careful planning and a long-term commitment. And it will be hard work – this is what Professor David Watson of Charles Sturt University (pictured) said about the mistletoe clearance work:
“it took teams of volunteers months and months to remove about 46 tonnes. It was a considerable logistical exercise. It was a royal pain in the ass.”
And, of course, his research proves it would have been better to have left it there…
Great to read about this – I saw the article in the Economist. I live in Durban, South Africa, close to the city centre, but with a marvellous nature reserve, Pigeon Valley, just across the road. My garden is coastal forest, unashamedly, and the local mistletoe, Tapinanthus (which species I am not certain, but I think it gracilis) has moved into the garden, attracting much life. We have had 75 bird species in the garden. See my posting today on wessadurban.blogspot.com. By the way, I have cousins living mainly around Ashton-under-Hill in Worcestershire; my one cousin has a farm which is very thoughtfully managed.
Hi Crispin, Thanks for your comment. I’m a little jealous of your Tapinanthus – as I do like the showier mistletoes (though, obviously, not quite as as much as Viscum album!). I got to know Tapinanthus sansibarensis for a few weeks back in the 1980s when studying Kenyan mangrove swamps, where it grew on a couple of the mangrove species. Your Tapinanthus picture reminds me of it, though T.s had darker red flowers. Interesting to hear you have cousins in Worcestershire – Ashton-under-Hill is well within Viscum album’s main range, so I assume they must have some on the farm?
Jonathan, sorry to respond so much later – didn’t check for a message. I did a bit more research, and in fact the most common mistletoe here is no longer classified as Tapinanthus. It is now Erianthemum dregei. Interestingly, it is moving into the invasive alien Syringa, Melia Azedarach, which is one way of limiting its negative impact. The other mistletoe I am trying to locate is Tieghemia quinquenervia. It is much more limited in its host trees, going for Chaetachme Aristata (Thorny Elm) and Celtis Mildbraedii (Natal Elm). The latter is a very sparsely distributed tree, with just a few in South Africa except in the nature reserve across the road, where there are probably 50. So I am trying to locate it by peering into the canopy to see if I can locate any of the red flowers. All the best.
Crispin Hemson
I have just come across this while doing an internet search, after a horticulturalist friend suggested that the parasitic plant that has appeared during the past year on the upper (and out of reach) branches of our plane tree might be mistletoe. I never even realised mistletoe occurs in S.Africa, let alone Durban. (I’m not much of a botanist/ horticulturalist). The plane tree must be over 40 years old, as we have been here since 1976, and the tree was already well established then, albeit much smaller than it is now. The house was built in the mid-1960s, so the tree could have been planted then.
I have some concern that the mistletoe will ultimately be detrimental to the plane-tree, which thanks to my husband’s efforts many years ago survived a massive colonising onslaught by weaver-birds that started to kill it when they stripped off its leaves in spring and summer. Being next to bush, we also have a fair amount of bird-life as well as large troupes of vervet monkeys which drop palm-tree seeds everywhere, resulting in “volunteer” palms growing prolifically, such as they never would if I tried to grow them!