My Shea Story

From pollinators to policy – the story of applied ecological research across continents

Back in 2015, I had a blast from the past when a former colleague (we did our PhDs together at Southampton University in the late 1990s) got in touch to ask whether I’d like to work on pollination of shea (Vitellaria paradoxa) in West Africa. I had done very little tropical ecology work, and had to google shea, but said “Sure, why not?”. Before I knew it, I was in Ghana, learning about shea growth, production and markets as part of a team including scientists, international and national NGO workers, and representatives from the shea industry.

We designed an experiment across six sites in Ghana and southern Burkina Faso, and the following year, I was back setting up the experiment. We did pollinator exclusion trials to test for pollinator dependency, and surveyed which insects were visiting the flowers and actually doing the pollinating. This pilot study showed that the majority of flower visitors to shea (88%) were bees, most frequently small social stingless bees (Hypotrigona gribodoi), but native honey bees (Apis mellifera adansonii) were also common visitors to flowers early in the morning. The number of fruit produced per inflorescence was significantly lower when insects were excluded during flowering by bagging, but any fruits and seeds that were produced in bagged treatments were of similar weight to un-bagged ones. This work was published in the Journal of Pollination Ecology.

Of course, this study generated as many questions as it delivered answers, and so we sought more funding. Fortunately, we were successful and between 2016 and 2019, we were partners on a U.K government Darwin Initiative funded project researching both the impact of habitat diversity upon pollination services in shea parklands of southern Burkina Faso, and also how farmer led agro-ecological interventions, referred to as the ‘Trees Bees and Birds strategy’ can increase on-farm biodiversity, and improve parkland habitat at landscape level.

This time, I was lucky enough to go back to Burkina Faso with Dr Aoife Delaney, who had just completed her PhD with me. We set up an experiment to compare pollination and fruit production in landscapes with different levels of biodiversity, to try and understand whether in more degraded sites, the shea was adequately pollinated. Aoife stayed in Burkina Faso for six months to complete the field study, working with our local partners and farmers.

We found that in the more biodiverse sites, honey bees were observed more frequently, whereas other bee species were generally widespread, but they did visit trees in greater numbers at diverse sites. We also found that shea fruit production was significantly limited due to lack of pollination and that the degree of pollination limitation was greater in sites with lower levels of tree and shrub diversity. This work was published in Journal of Applied Ecology. See our blogs on The Applied Ecologist and RSPB sites for more.

So, the ecological conclusion was to maintain or improve habitat level biodiversity to optimise levels of pollination for shea, and presumably other plants in the Parklands. This biodiversity would then provide multiple benefits to people, including forage and shelter for livestock, firewood, building materials and traditional medicines. The presence of trees helps to bind the soil, reducing organic matter loss, and leguminous tree species in the parklands including acacia and African locust bean improve soil fertility. The populations of insect and bird species helps to provide pollination and pest control functions.

However, these are heavily populated landscapes and increased demand for land under active cultivation has led to more land clearance, shorter fallow periods and smaller fallow areas in the Parkland. With less time and space for natural regeneration to occur, the trees and shrubs in the shea parklands have become less diverse and less abundant. Thus there are trade-offs to be made in land-management, and sustainable solutions need to be found.

To address this issue, together with Elaine Marshall the Project Leader at BirdLife International, we highlighted these issues at a “Lessons Learned” workshop in June 2019 at the David Attenborough Building in Cambridge, focusing on partner-led community conservation approaches around the world, including the Trees Bees and Birds strategy. We summarised the challenges and solutions in terms of tackling ecological restoration as follows..

CHALLENGES:

1. We need solutions to reverse the drivers of biodiversity decline
2. Nature appears to be invisible in a lot of decision-making
3. Loss of biodiversity and ecosystem degradation damages the flows of benefits we get from nature
4. There are conflicts and trade-offs in ecosystem restoration
5. Research and education efforts are currently inadequate

SOLUTIONS:

1. Research and (importantly) knowledge transfer
2. Facilitation of Indigenous Local Knowledge (ILK) sharing
3. Target messages and roll out across sectors
4. Build on international initiatives for restoration and frameworks for accounting for the benefits from nature

And in 2020, we published a Policy Briefing on ” Building Resilient Landscapes and Livelihoods in Burkina Faso’s Shea Parklands” to try and address some of the issues that had been raised during the project. This highlighted the outcomes of our research, and made policy-relevant recommendations. This Briefing can be downloaded below.

And we are continuing to do the research. Latif Nasare, Lecturer at University for Development Studies in Tamale, Ghana, is conducting his PhD on shea pollination, and I’m co-supervising him. He’s investigating patterns of shea flowering phenology, how pollinator abundance varies with climate, the effects of honey bee keeping on shea yields, and forage resources for pollinators outside of the shea blooming period.

Latif is just completing his first field season, and I’m anxiously waiting for news of how he has got on, and for travel restrictions to be lifted so that I can go back to this wonderful part of the world to continue my shea story.

About the Author: Dr Jane Stout is Professor in Botany at Trinity College Dublin, and leads the Plant-Animal Interactions Research Group. She is co-founder of the All-Ireland Pollinator Plan and Natural Capital Ireland.