Abstract Small features in ecological systems are often underrepresented in conservation monitoring, management and policy. Tree cavities and other forms of refuge play disproportionately large ecological roles due to their importance for shelter and rearing vulnerable offspring. Giant panda (Ailuropoda melanoleuca) cubs are highly altricial, and dependent on dens. In Fengtongzai—a reserve with cavity-containing old growth forest—we measured 19 structural and microhabitat variables in potential tree dens. We also established data loggers in rock cavities in Foping Nature Reserve (which due to logging does not contain old growth) and tree cavities in Fengtongzai to monitor temperature and humidity inside and outside dens to evaluate microclimatic buffering. Fengtongzai pandas selected tree dens that were better concealed, with large interiors and entrances but smaller entrance to interior ratios. Microclimate inside dens differed dramatically from ambient conditions outside: in cold weather dens were warmer, in hot weather dens were cooler, dens were less humid and dens had more stable microclimates. Dens used by maternal pandas were warmer, drier and less variable than tree and rock cavities that were not used. Tree dens showed better capacity to buffer against extremes of temperature and humidity than did cave dens. Our findings have important conservation implications, including the value of den sites and the need for better monitoring and management. Specifically, management practices that preserve large old trees may increase carrying capacity and any experimentation with artificial dens as a conservation intervention should reference our findings on structural and microclimatic characteristics of preferred den sites.

中文翻译：

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巢穴质量在大熊猫保护中的作用

摘要 生态系统中的小特征在保护监测、管理和政策中往往没有得到充分体现。树洞和其他形式的避难所发挥着不成比例的巨大生态作用，因为它们对于庇护所和抚养脆弱的后代很重要。大熊猫 (Ailuropoda melanoleuca) 幼崽性情高，依赖巢穴。在风桐寨——一个带有空洞的古老森林保护区——我们测量了潜在树穴中的 19 个结构和微生境变量。我们还在佛坪自然保护区的岩洞（由于伐木不包含旧生长）和风桐寨的树洞中建立了数据记录仪，以监测窝点内外的温度和湿度，以评估小气候缓冲。风桐仔熊猫选择了隐蔽性更好的树窝，具有较大的内部和入口，但入口与内部的比率较小。巢穴内的小气候与外面的环境条件大不相同：在寒冷的天气里，巢穴更暖和，在炎热的天气里，巢穴更凉爽，巢穴的湿度较低，巢穴的小气候更稳定。与未使用的树洞和岩石洞穴相比，母熊猫使用的巢穴更温暖、更干燥且变化更少。树窝表现出比洞穴窝点更好的缓冲极端温度和湿度的能力。我们的发现具有重要的保护意义，包括巢穴的价值以及更好地监测和管理的必要性。具体来说，