UC Santa Cruz
Climate consequences for ecosystem functions, production and producer responses in coffee agroecosystems
- Author(s): Ennis, Katherine Kimberley
- Advisor(s): Philpott, Stacy M
- et al.
Coffee is an important commodity crop, providing livelihoods for hundreds of millions worldwide. Like most plants and agricultural crops, coffee is anticipated to be strongly impacted by climate change forecasts. Grown at high altitudes and often accompanied by shade trees that provide additional ecosystem and conservation value, coffee is particularly climate sensitive requiring specific rainfall regimes for flower and fruit development. In this research I used ecological and interdisciplinary approaches to examine different effects of seasonality and climate change on coffee systems. In the first two chapters I examine the role of seasonality in predator-pest interactions of a tropical coffee agroforestry system in the highest coffee producing municipality of Chiapas, Mexico. Specifically, I use experiments and field manipulations to assess the impact of seasonal rainfall as a driver of changes to insect communities and predator-prey consumption patterns between natural biocontrol agents (ants) and coffee insect pests. I find that ant predation is affected by microclimate and seasonal rainfall and that reduced rainfall alters ecological communities and ecosystem functions. In the third chapter, I use environmental and socio-economic approaches to examine the impact of climate and price fluctuations on coffee production and producers in Mexico. Combining spatially-explicit historical climate, production and price data from all coffee-growing municipalities in Mexico, I examined trends of climate and coffee production and then further characterized and quantified coffee producer’s responses to changing conditions of climate and price. I found that coffee-specific climate variables contributed to a 60% decline in Mexican coffee production since its peak in the 1990s, and that farmers’ management responses to soaring temperatures, limited rainfall and price volatility are generally limited to reducing the proportion of planted area they harvest each year. In sum, my research examines seasonal climate impacts on coffee agroecosystem communities, functions and production. Specifically, I find (1) an unexplored potential effect of shifting seasonal climate on the natural biological control provided by ant predators; and that (2) climate change has already affected coffee production in Mexico, but producers have limited capacity to respond to changes. The findings of this research highlight the potential consequences of unmitigated global climate change for coffee agroecosystems and farmworker livelihoods.