Tree species diversity and vegetation structure in shade coffee farms in Veracruz, Mexico

Background

While some studies have argued that shade coffee enables similar biodiversity to remnant forest fragments, others contest that the ecological functions of shade coffee can be assumed to be the same or that policies promoting shade coffee will also benefit remnant forest fragments. Not all taxa have been thoroughly studied in shade coffee. This study reports on tree species diversity and vegetation structure in shade coffee farms in Veracruz, Mexico.

Research goals & methods

Using 15 shade coffee farms and two forest reserves located in central Veracruz, Mexico, the authors evaluated how tree vegetation structure and richness changed as a function of management type and compared to that remnant forest fragments. Plots were established in shade monocultures, simple polycultures, diverse polycultures, and nearby cloud forest fragments.

Forest vegetation structure was higher than in coffee farms, except for mean canopy height that was similar to that in simple and diverse polyculture farms. Within coffee farms, tree density was generally higher in simple monocultures, whereas basal area and both mean and maximum height were higher in simple and diverse polyculture farms. Simple and diverse polyculture farms had the highest proportions of animal-dispersed species and were similar to forest.

Conclusions & takeaways

These results suggest that shade diversity is actively managed by coffee farmers and that all three types of coffee management studied may have an important role to play in the conservation of regional biodiversity. Considering factors such as complementarity, landscape heterogeneity, functional diversity, and the rigor of vegetation surveys may also help improve the validity, and thus the impact, of coffee certification programs designed with the goal of conserving tropical montane biodiversity.