Grenada Frog (Pristimantis euphronides)

Endemic · Endangered · A Montane Forest Specialist

The Grenada Frog is one of Grenada’s most distinctive species and one of the island’s few endemic vertebrates. Found nowhere else in the world, it occupies a narrow band of cool, mist-rich montane forest in the central highlands. Its soft clicking call, bronze iris, triangular finger pads, and orange-red hind thighs distinguish it from the introduced frogs that now dominate much of the island’s lower elevations.

Because it depends so strongly on humid, shaded forest, the Grenada Frog is highly sensitive to canopy disturbance, drying winds, and changes in moisture. Safeguarding this species means protecting the ecological integrity of Grenada’s cloud forests.

Habitat and Ecology

The Grenada Frog lives almost entirely in:

dense leaf litter of undisturbed montane forest
cool, moist microhabitats above roughly 300 m elevation
shaded gullies, mossy roots, and decaying logs
high-humidity zones that retain moisture year-round

Earlier work by herpetologists such as Henderson and colleagues first documented these patterns, establishing the species’ narrow elevation range and its strong dependence on intact, upland forest.

Recent research continues to confirm that the species’ survival is tied to forest continuity, moisture, and elevation — all of which are increasingly shaped by storms, development, and invasive species.

Threats

Habitat Loss and Forest Disturbance

Any reduction in canopy cover dries the forest floor, increases heat, and reduces the shaded, moisture-rich microhabitats the species depends on. Forest clearing, footpath widening, and storm-related damage all alter conditions in ways that can make upland forest unsuitable.

Climate Variability and Drying

Montane forests are experiencing shifts in rainfall and mist patterns. Because the Grenada Frog is highly moisture-dependent, even subtle changes in humidity and temperature affect its calling, movement, and reproduction.

Invasive Amphibians

The introduced Lesser Antillean Whistling Frog thrives in disturbed or open environments. While it does not appear to displace the endemic frog in intact montane forest, it outnumbers the endemic species at edges, agricultural margins, and drier forests — areas that expand when disturbance increases.

Storm Impacts and Vegetation Change

Recent hurricanes have altered upland forest structure, creating new gaps and changing leaf-litter composition. Increased light and drying reduce the cool, shaded conditions required by the endemic species.

Limited Range

The species’ extremely small distribution makes it vulnerable to any environmental change. With the entire global population restricted to Grenada’s upland forests, localized impacts have global consequences.

Research Insights and Long-Term Ecological Understanding

Modern ecological research builds on decades of earlier study. Foundational work by Henderson and colleagues established the frog’s restricted elevation range and its strong dependence on intact montane forest.

More recently, ecologist Billie Harrison has expanded this foundation through detailed field investigations. Her work focuses on:

mark–recapture studies to understand movement and site fidelity
microhabitat use, examining moisture, canopy structure, and litter conditions
calling behaviour, supporting improved detection
interactions between endemic and introduced frogs, clarifying how habitat quality shapes species overlap

Together, this growing body of research strengthens understanding of how the species uses the landscape and what conditions are essential for long-term persistence.

Across studies past and present, a consistent ecological theme emerges:
habitat quality—especially moisture, shade, and forest continuity—is the strongest predictor of where the Grenada Frog can survive.

Partners & Collaboration

The Grenada Frog conservation work brings together government agencies, academic researchers, and local conservation organisations with long-standing experience in Grenada’s upland ecosystems.

Government partners involved in this work include the Forestry and National Parks Department within the Ministry of Agriculture, Lands, Forestry, Marine Resources & Cooperatives, and the Ministry of Climate Resilience, the Environment & Renewable Energy. Forestry provides site access, ecological oversight, and continuity across protected areas where the species occurs.

Academic and research partners contribute the long-term scientific foundation for understanding the species. Earlier ecological studies by Henderson and colleagues established the frog’s range, elevations, and habitat associations. More recent work by researcher Billie Harrison has focused on fine-scale ecology—mark-recapture, movement, calling behaviour, and habitat use—helping to clarify the species’ persistence in mixed forests and areas shared with the invasive Johnstone’s Whistling Frog. St. George’s University supports this work through additional amphibian surveys, specimen documentation, and comparative ecological research.

Conservation organisations include the Gaea Conservation Network, which led the 2024–2025 surveys and is integrating amphibian monitoring into Grenada’s broader biodiversity programmes. Community partners across St. Andrew, St. David, and the Grand Etang/Annandale landscapes also contribute local knowledge and site-level observations, strengthening the national understanding of where the frog persists.

Going forward, Gaea, Forestry, and Billie Harrison will collaborate on continued field surveys, range refinement, and long-term monitoring to support conservation planning for the species. This partnership ensures that research, management, and community knowledge move together toward the shared goal of maintaining the Grenada Frog across its upland forest habitats.