Temporal and spatial patterns in flowering phenology were assessed for eight tropical African tree species. Specifically, the frequency and seasonality of flowering at seven sites in central Africa were determined using field data, graphical analysis and circular statistics. Additionally, spatial variation in the timing of flowering across species range was investigated using herbarium data, analysing the relative influence of latitude, longitude and timing of the dry season with a Bayesian circular generalized linear model. Annual flowering was found for 20 out of the 25 populations studied. For 21 populations located at the north of the climatic hinge flowering was occurring during the dry season. The analysis of herbarium collections revealed a significant shift in the timing of flowering with latitude for E. suaveolens, and with the timing of the dry season for M. excelsa (and to a lesser extent L. alata), with the coexistence of two flowering peaks near the equator where the distribution of monthly rainfall is bimodal. For the other species, none of latitude, longitude or timing of the dry season had an effect on the timing of flowering. Our study highlights the need to identify the drivers of the flowering phenology of economically important African tree species.

中文翻译：

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热带非洲树种开花时间的纬度变化：来自实地观察和植物标本馆收藏的见解

对八种热带非洲树种的开花物候的时空格局进行了评估。具体而言，使用实地数据、图形分析和循环统计确定了中非七个地点的开花频率和季节性。此外，使用植物标本室数据研究了跨物种开花时间的空间变化，使用贝叶斯循环广义线性模型分析了旱季纬度、经度和时间的相对影响。在所研究的 25 个种群中，有 20 个发现每年开花。位于气候枢纽北部的 21 个种群在旱季开花。对植物标本馆藏品的分析揭示了开花时间随纬度的显着变化E. suaveolens，并且随着旱季的时间M. excelsa（并且在较小程度上L. alata)，在赤道附近有两个开花高峰并存，月降雨量分布呈双峰分布。对于其他物种，旱季的纬度、经度或时间都没有影响开花时间。我们的研究强调了确定经济上重要的非洲树种开花物候驱动因素的必要性。