Data from: Resource tracking and its conservation implications for an obligate frugivore (Procnias tricarunculatus, the three-wattled bellbird)

In Monteverde, Costa Rica, the vulnerable Three-wattled Bellbird (Procnias tricarunculatus) feeds primarily upon the fruit of Lauraceae species during its reproductive and post-reproductive seasons. To understand and advance appropriate conservation measures, this study identified the bellbird’s foraging challenges in its search for a temporally and spatially fluctuating resource. Although there are at least 96 species of Lauraceae found in the five life zones of Monteverde, the distinct distributions of tree species both among and within life zones require the bellbirds to track seasonal fruiting across the various zones. In this six-year study, we monitored the fruiting of tree species and bellbird abundance in 24 study plots within its post-reproductive life zone, the Premontane Wet forest, in order to identify preferred bellbird food resources and how the fruiting of these species drives the spatial distribution of the bellbird. Our research revealed phenological patterns of annual, biennial, and triennial fruiting with high levels of fruiting synchrony within several identified key fruit species. Of critical conservation importance is that no single species of Lauraceae produced a consistent food supply for bellbirds each year. Therefore, even within life zones, the bellbird’s survival depends on its mobility to search for and obtain fruit, as well as the availability of fruits of multiple tree species. The conservation implications include focused attention on multiple core areas within given life zones, protection of existing forest and remnant trees, and forest restoration with plantings of multiple tree species. We suspect that other tropical frugivorous species face similar conservation challenges.

在哥斯达黎加蒙特韦德地区，易危物种三肉垂钟伞鸟（Three-wattled Bellbird, Procnias tricarunculatus）在繁殖期与繁殖后期主要以樟科（Lauraceae）植物的果实为食。为理解并推进适宜的保护策略，本研究探究了该钟伞鸟在搜寻时空动态波动的食物资源时所面临的觅食难题。尽管蒙特韦德地区的五个生命带中至少分布有96种樟科植物，但各生命带之间以及同一生命带内部的树种分布格局差异显著，迫使钟伞鸟需追踪不同区域的季节性结实规律。在这项为期六年的研究中，我们于该鸟繁殖后期的栖息生命带——山地湿林（Premontane Wet forest）内的24个研究样地中，监测了树种结实情况与钟伞鸟的种群丰度，以期明确钟伞鸟偏好的食物资源，以及这些物种的结实动态如何驱动钟伞鸟的空间分布。本研究揭示了多个关键结实树种的物候模式：结实周期涵盖一年生、两年生及三年生，且这些物种内部的结实同步性较高。极具保护警示意义的是，没有任何一种樟科植物能够每年为钟伞鸟提供稳定的食物来源。因此，即便在同一生命带内，钟伞鸟的生存也依赖于其搜寻和获取果实的移动能力，以及多种乔木树种果实的可获得性。本研究的保护启示包括：重点关注指定生命带内的多个核心区域，保护现存森林与残存林木，以及通过混植多种乔木树种开展森林修复工作。我们推测，其他热带食果动物可能也面临类似的保护挑战。