Climate change impact on cultivated and wild cacao in Peru and the search of climate change‐tolerant genotypes

Viviana Ceccarelli,Diego Zavaleta,Sphyros Lastra,Carlos Armando Rodriguez,Tobias Fremout,Evert Thomas,Wilbert Cruz Hilacondo,Enrique Arévalo‐Gardini,Sixto Imán Correa

doi:10.1111/ddi.13294

Abstract

AbstractAimCacao (Theobroma cacao L.) is expected to be vulnerable to climate change. The objectives of this study were to (a) assess the future impact of climate change on cacao in Peru and (b) identify areas where climate change‐tolerant genotypes are potentially present.LocationPeruMethodsDrawing on 19,700 and 1,200 presence points of cultivated and wild cacao, respectively, we modelled their suitability distributions using multiple ensemble models constructed based on both random and target group selection of pseudo‐absence points and different resolutions of spatial filtering. To estimate the uncertainty of future predictions, we generated future projections for all the ensemble models. We investigated the potential emergence of novel climates, determined expected changes in ecogeographical zones (zones representative for particular sets of growth conditions) and carried out an outlier analysis based on the environmental variables most relevant for climate change adaptation to identify areas where climate change‐tolerant genotypes are potentially present.ResultsWe found that the best modelling approaches differed between cultivated and wild cacao and that the resolution of spatial filtering had a strong impact on future suitability predictions, calling for careful evaluation of the effect of model selection on modelling results. Overall, our models foresee a contraction of suitable area for cultivated cacao while predicting a more positive future for wild cacao in Peru. Ecogeographical zones are expected to change in 8%–16% of the distribution of cultivated and wild cacao. We identified several areas where climate change‐tolerant genotypes may be present in Peru.Main conclusionsOur results indicate that tolerant genotypes will be required to facilitate the adaptation of cacao cultivation under climate change. The identified cacao populations will be target of collection missions.

Highlights

Climate change is expected to severely impact agricultural production
We modelled the current and future distribution of cultivated and wild cacao in Peru by comparing multiple ensemble models constructed using different pseudo-absence selection approaches and resolutions of spatial filtering
We modelled the distribution of suitable habitat of cultivated and wild cacao in Peru by comparing multiple ensemble models constructed using different pseudo-absence selection approaches and resolutions of spatial filtering

Summary

Introduction

Climate change is expected to severely impact agricultural production. Global average temperature has already increased by about 0.85°C during the period 1880–2012 and is projected to further increase by 1.4–3.1°C towards the end of this century (Stocker et al, 2013). Rising temperatures in combination with changes in precipitation patterns and higher frequencies of extreme droughts and floods (Cai et al, 2014; Stocker et al, 2013) are expected to reduce crop yields and threaten farmers’ livelihoods around the world (Parry et al, 2004; Porter et al, 2014). Evolved as an understory tree native to the Amazon basin, cacao is a drought-sensitive species and high temperatures and low precipitation can negatively impact its growth, productivity and yield quality (Daymond & Hadley, 2008; Moser et al, 2010; Zuidema et al, 2005). Increasing evidence indicates that climate change is already affecting cacao cultivation around the world, resulting in higher mortality, declines in yield quality and quantity (Medina & Laliberte, 2017), and increased incidence of diseases (Gateau-Rey et al, 2018)

Objectives

Findings

Discussion

Conclusion