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By: Holly Kragiopoulos 11 October 2018
** This is a guest post from one of the UK’s top ecologists, John Altringham, from the University of Leeds.
Environmental responsibility is something we are very passionate about here at North Star and we wholeheartedly recognise how vital it is for the production of high quality coffee both now and in the years to come.
This blog post discusses why bees are so beneficial to Arabica despite the fact it is self pollinating and why coffee contributes positively to the health of bees. To learn more, make sure you follow John on Twitter to stay in the loop with new research and insights**
Arabica coffee plants, those that produce high quality coffee, are self-pollinating so they don’t need the help of bees and other insects – or so the story goes. But several careful studies have shown that bees can not only increase the yield of an Arabica crop by 50% or more, but they can improve crop quality too. And that’s just the beginning – in addition to transferring pollen, bees help to move around some of the vital bugs and beasts that keep coffee plants healthy. Coffee plantations are, to varying degrees, functioning ecosystems in which animals and plants co-exist – competing with each other, eating each other, but also benefiting each other. This community has its fair share of pests, from insects to microbes, that can damage the coffee in various ways and reduce the size and quality of the crop. However, the community also has natural pest-controllers such as frogs, snakes, birds, bats, insects, spiders – right down to microbes. There’s a growing belief, backed up by hard science, that for many crops, coffee included, preserving these ecosystems is not only good for the environment, but it also makes good economic sense.
Agricultural intensification, through the use of new plant varieties, artificial fertilisers, pesticides and other practices, has massively increased coffee crop yield. However, this has often been at a huge environmental cost – agricultural intensification is not always sustainable. In a rush to produce bigger crops systems have been adopted that drastically reduce biodiversity, decrease soil fertility and structure and are bad for human health. But, the way we grow coffee, or at least specialty coffee, is changing, slowly but surely. In my blog entry back in June I talked about the value of shade-grown coffee to wildlife and hinted at the importance of bees – let’s take a closer look at these busy pollinators.
Back in the 1970’s a large-scale study on an Arabica plantation in Jamaica found that the introduction of honey bees led to 52% more ripe coffee berries, a result that was repeated over several harvests. This was done by netting a whole field, excluding bees from some plants and giving them access to others and monitoring the differences. Thirty years later, independent studies in Indonesia and Panama showed that wild bees also increase coffee yield, with over 20 native bee species visiting Arabica coffee flowers in both countries. The importance of cross-pollination by bees in these later studies varied enormously, but it was always significant. Different coffee strains appear to vary in the proportion of flowers that need cross-pollination, from just a few percent to over 90%. Many other studies in coffee-growing areas across the world report similar results, giving growers powerful reasons to nurture bees and the habitats they depend on.
I said at the beginning that cross-pollination by bees can also improve crop quality. This is because the beans on a bush, or even on a single branch, do not ripen at the same time. To ensure every bean is at the peak of ripeness for the best flavour and sweetness would mean picking individual beans as they ripen, which is usually prohibitively expensive. The compromise is to pick whole bunches when most in the bunch are ripe, accepting that some may be under- or over-ripe. Cross-pollination by bees improves the synchrony of pollination and ripening, so that a higher proportion will be at their best when picked.
So, if Arabica growers want to increase yield and quality, what should they do? They could bring in honey bee hives to pollinate their coffee flowers, or they could improve the habitat on their plantations to encourage native bees. Which is most appropriate will depend on the conditions at each plantation, but if possible, native bees are best, since studies suggest they are more effective pollinators, and if they are given the right conditions, they look after themselves. Introducing honey bees typically leads to a decline in wild, native bees, since they can’t compete with the huge commercial colonies, so this needs careful thought. Honey bees also need to be looked after and the cost of maintaining them needs to be factored in. However, they do make honey, and coffee blossom honey is marketed from at least two coffee-producing countries as a profitable sideline.
How do you support your neighbourhood wild bees? You give them food and shelter. Most species are solitary or live in relatively small colonies, making their nests in the ground or in trees, often digging their own burrows. Growers can provide low earth banks for ground nesters and old or dead trees for those that prefer them. They can even save them the trouble of digging by providing simple, cheap artificial nests. When the coffee is not in flower they will thrive on native flowering plants, and the growers need to set aside only small patches of their land to support them. The bees will repay growers with interest. Setting aside or managing land for biodiversity is something many growers do already to meet various sustainability accreditation’s – and many have noticed the benefits they get from the bees.
This is not a simple, one-dimensional relationship. In return for a little nectar, the coffee plant gets more from the bees than having its pollen spread around. Coffee has many commercially important pests and diseases and bees can carry viruses, bacteria, fungi and even other insects that can help control them. This is all part of any natural, healthy ecosystem, but it can also be enhanced commercially if honey bees are used as pollinators, in a process called pollinator bio control vector technology (PBVT) – something that is being researched by agricultural scientists and ecologists working on Brazilian coffee.
It will come as no surprise to hear that climate change is going to have a significant effect on where coffee can be grown in the future – the effects are already becoming apparent. The effects of climate change on bees is likely to be different, which could have a profound influence on the mutually beneficial relationship between bees and coffee. In some areas, it may exacerbate the effects of climate on coffee production, in others it could ameliorate them – a topic for another blog?
A final bit of bee biology – some plants provide a little shot of caffeine with their nectar – it improves the bees’ memory so they remember the distinctive scent of the plant’s flowers and come back. There are some interesting ramifications to this story which I’ll also leave for another time!
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