Bats, Birds, and Chocolate: How Shade-Grown Cacao Sustains Wildlife in Dry Tropical Forests

Redacción HC
28/09/2023

In the dry tropical forests of northern Peru, a quiet revolution is taking place—one that involves chocolate, biodiversity, and sustainable farming. A recent study published in Agriculture, Ecosystems and Environment reveals that shade-grown cacao farms can serve as seasonal refuges for insect-eating birds and bats, depending on how close they are to natural forest remnants and the time of year.

As climate pressures and agricultural expansion continue to threaten biodiversity hotspots, this research provides critical evidence that agroforestry systems can help conserve key animal species, even in fragile ecosystems like tropical dry forests.

When Forests Meet Farmlands: The Research Question

Tropical dry forests are among the most endangered ecosystems on the planet, with extensive land conversion for agriculture, especially cacao production. While shade-grown cacao is often considered environmentally friendly, scientists have questioned whether these systems truly support biodiversity, particularly for aerial insectivores like birds and bats that provide essential ecosystem services such as pest control.

The central question of this study was:

How do seasonal changes (dry vs. rainy season) and distance from dry forests affect the diversity and abundance of birds and bats in shaded cacao plantations?

Understanding this relationship could inform how to design agroforestry systems that are not only productive but also biologically rich.

Methodology in the Field: From Mist Nets to Ultrasound

Researchers conducted the study across 12 cacao farms in northern Peru, varying in proximity to dry forest patches—from adjacent to isolated. Over the course of more than a year, the team monitored wildlife using mist nets to capture birds and ultrasonic detectors to record bats, during both dry and rainy seasons.

Species were categorized by functional traits such as diet, forest dependence, and mobility. The team applied mixed-effects statistical models to assess how distance from forest and seasonality influenced species presence.

The methodology accounted for several challenges, including the difficulty of detecting cryptic species, the complexity of habitat categorization, and monthly—rather than weekly—sampling limitations.

Key Findings: Wildlife Patterns Shift with Season and Distance

More Bats in Farms Year-Round

In a somewhat surprising result, insectivorous bats were more abundant in cacao farms than in nearby forests throughout the year. These were primarily generalist species well adapted to agroforestry environments.

“Bats appear to thrive in the structural complexity and insect abundance of shaded cacao,” said co-author Bea Maas of the University of Vienna.

Birds Flock to Farms—But Only in the Dry Season

Bird dynamics told a more nuanced story. In the dry season, shaded cacao farms—especially those within 500 meters of a forest—had twice as many insectivorous bird species as isolated ones. However, during the rainy season, bird diversity between farms and forests was more balanced, possibly due to increased food availability across all habitats.

Functional Traits Determine Resilience

Species with high mobility or generalist diets were less affected by distance from forest, while forest-dependent specialists declined sharply in isolated farms, especially in the dry season. This highlights how ecological traits influence how well species can adapt to fragmented agricultural landscapes.

Bigger Picture: Why This Matters

These results bolster the argument that shade-grown cacao farms can support biodiversity—but proximity to natural forests and seasonal dynamics are key. Farms near remnant forests offer temporary habitat and food resources, particularly during the dry season when natural resources become scarce.

Ecosystem Services and Cost Savings

Increased presence of birds and bats translates into enhanced pest control, which can reduce pesticide use and save farmers money. For local cooperatives and organic growers, these benefits also offer marketing opportunities in the premium chocolate market.

Policy Implications

The study offers actionable insights for policymakers:

1. Prioritize cacao agroforestry in ecological restoration programs.
2. Subsidize conservation-friendly farming practices near natural forests.
3. Integrate biodiversity monitoring into agricultural extension services.

In countries like Peru, where cacao is a major export and dry forests are under siege, this research supports a win-win model for conservation and agriculture.

The Path Forward: From Research to Action

The authors recommend expanding this type of functional, seasonal biodiversity research to other regions and taxa—such as pollinators and seed dispersers—to gain a fuller understanding of how agroforestry systems interact with biodiversity and ecosystem services.

They also propose the development of co-designed biodiversity guides with farmers to ensure knowledge transfer and local ownership.

Topics of interest

Biodiversity Climate