The PhenoChange network protocol for monitoring leaf phenology in tropical dry ecosystems using phenocameras

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Abstract Tropical dry ecosystems (TDEs) cover half of the tropics and play a key role in global carbon dynamics. TDEs present distinct canopy and ground layers that often exhibit contrasting phenological patterns. On‐the‐ground observations of phenology by the human eye, though valuable, may suffer from limited temporal resolution and observer biases. Satellite data offer broad coverage but are limited by cloud interference and low spatial resolution. Phenocameras have emerged as a cost‐effective, high‐frequency monitoring tool, yet most studies rely on tower‐mounted set‐ups that may miss ground‐layer dynamics. Here, we developed a standardized protocol for simultaneously monitoring the leaf phenology of canopy and ground‐layer vegetation in TDEs, using pole and tree‐mounted trail cameras (phenocameras). The protocol was tested across savanna, dry forest and woodland sites in Brazil and Angola. We demonstrated that phenocameras mounted on trees or poles can effectively capture canopy and ground‐layer phenological patterns, that cameras should be mounted on fixed poles and, where not possible, on large trees. We found that the seasonal patterns of ground‐layer phenology captured by cameras mounted at 1 versus 2 m above the ground are strongly correlated. We recommend installing at least three cameras per site to provide more precise estimates of community‐level patterns and to maintain continuous time series in the case of camera failure or loss. Our protocol enables scalable, replicable phenological monitoring of plant communities and the canopy and ground layer, including in remote areas, enhancing our capacity to detect and interpret vegetation responses to environmental variability in tropical dry ecosystems.

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