PhD student Hannah Rigney on her fieldwork experiences in Ghana 

In West Africa, more than 2 million small holder farmers grow cocoa that is exported worldwide, eventually becoming the chocolate bars we know and love.  

But cocoa production faces huge sustainability challenges. Global demand for chocolate is rising, but aging plantations, decreasing soil fertility, and increasing pests and disease mean that productivity is low. These environmental challenges, combined with socio-economic factors, often lead farmers to clearing new land to plant cocoa to meet this demand, rather than increasing productivity on already cultivated land.  This means that cocoa production is associated with massive amounts of deforestation and thereby poses a threat to tropical biodiversity.

But there is hope. Agroforestry, often hailed as a solution to reconcile agricultural production with biodiversity conservation, has been shown in previous work (led by Dr Wilma Hart) to have the possibility to provide habitat for biodiversity in agricultural landscapes, and can be implemented without a cost to production.  

In my PhD, I will use cocoa growing areas in Ghana as a case study for asking the how, why and where we can use agroforestry to improve outcomes for tree diversity in largely deforested, but historically biodiverse tropical areas. To begin to answer some of the big questions, I embarked on a massive field-campaign in Ghana last year. I share some of my impressions and experiences below. 

Fieldwork experiences in Ghana 

Soggy boots. Dense thickets. Spectacular rainforest, with trees so tall you can’t see their top. The morning chorus of birds, deafening our ears with the break of dawn. A sudden darkness in the middle of the day, as a storm rumbles over the looming canopy. Curious kids, and adults alike, shouting “OBRUNI!” as we walk by (“obruni” is the Akan/Twi word for ‘foreigner’ and has just been added to the Oxford English Dictionary). Ants attacking me in the farms. Ants chasing me in the forest. Ants biting me in my bed (yes, there were ants in my bed). Ants crawling into my dreams (nightmares). The rustle of leaves in the dense litter as a snake rushes past. Farmers excitedly showing us the trees they’ve planted, the cocoa pods they’ve harvested. 

Days spent traversing the thick rainforest, climbing up and up and down again, steep, slippery slopes… 

I spent seven months of last year collecting data in the field in cocoa farms and rainforests of the Central Region of Ghana, West Africa. For most of that time, I lived in a house with our field team in a town called Assin Fosu, where we could access Kakum National Park - a protected rainforest that belongs to the Upper Guinea forest zone biodiversity hotspot - as well as the cocoa-farming landscape that surrounds it.  

I was joined on this trip by Charlotte Jenkins who daringly said yes to 5 months of fieldwork in Ghana for her Honours year. We went into this as strangers and came out the other end as good mates who have seen each other through all the highs and lows such a field campaign can bring. Our work over there was supported by, and would not have been possible without, a team of local experts: Jonathan Dabo, a botanist; Mohammed Yombu and David Gorlecku, field technicians; and Robert Oteng, ornithologist. With my focus on tree diversity, I worked particularly closely with Jonathan and Mohammed. I was privileged to spend my days with them learning how to identify trees using bark and slash characteristics, their ecology and natural history, and their traditional medicinal and culinary uses.  

We’d start each day in the cocoa by driving to a village and introducing ourselves to the farming families and village chiefs. We’d explain our work and then with their blessing, head out to the farm to set up our plots. The generosity and warmth of the communities we worked with will stay with me forever. Then, the teams would split up. The bird and mammal team would head off to start their surveys and set up their loggers and cameras, and my plant team and I would get cracking with our trees. In each subplot we would record the identity, diameter and height of all the trees, and I also recorded some measurements of crown characteristics, like crown width and height.  

I ended my surveys in the cocoa with records of 152 unique species across 3694 individual trees in 187 plant plots. One question I will be looking at with this data is how tree diversity changes with differences in shade-tree cover and with changing landscape context – for example, whether the farm is close or far away from the protected forest.  

To have a reference point for the tree diversity we found in the cocoa farms, we also conducted tree surveys in the nearby rainforest. The days in the forest were some of the most physically demanding but incredibly rewarding field days of my life. We spent hours hiking in the rain through the dense vines and lianas, but we also got to see some spectacular sights. Spot-nosed monkeys swinging through the canopy, green vipers curled up to sleep on a branch, the footprints of forest elephants, the giant trees of the forest – the 70 m tall Ceiba pentendra, Hornbills screeching and screaming so we know they are the custodians of the forest, and even a glimpse of the Great Blue Turaco flying high above. For the bird nerds out there: I was also lucky enough to see the White-necked Picathartes up close in its rocky abode.  

I’ll most likely be heading back to Ghana later this year for a shorter stint to collect some data on how different tree species might influence cocoa yield. But for now, I am looking forward to some time digging into this huge dataset I have collected and look forward to finding interesting patters and hopefully some promising signs for how we can better reconcile agricultural production with biodiversity conservation.