Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil.
Departamento de Botânica, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
PLoS One. 2021 May 7;16(5):e0251360. doi: 10.1371/journal.pone.0251360. eCollection 2021.
Changes in phenological events have been vastly documented in face of recent global climate change. These studies are concentrated on temperate plants, and the responses of tropical species are still little understood, likely due to the lack of long-term phenological records in the tropics. In this case, the use of herbarium specimens to gather phenological data over long periods and wide geographic areas has emerged as a powerful tool. Here, we used four Melastomataceae species endemic to the Brazilian Atlantic Forest to evaluate phenological patterns and alterations as responses to recent climate changes. Phenological data were gathered from Reflora Virtual Herbarium specimens collected between 1920 and 2018, and analyzed with circular statistics applied to the intervals 1920-1979, 1980-1999, and 2000-2018. The effects of temperature range, average temperature, precipitation, and photoperiod on flowering and fruiting of each species were tested using multiple linear regressions. Through circular statistics, we detected changes, mostly delays, in the flowering of Miconia quinquedentata, Pleroma clavatum and P. trichopodum, and in the fruiting of M. acutiflora, P. clavatum and P. trichopodum. We also found that flowering and fruiting occurrence were related to local climatic conditions from months prior to the collections. We found marked phenological variations over the decades and also that these variations are associated to global climate change, adding up to the large body of evidence from higher latitudes. Our results also support herbarium collections as an important source for long-term tropical phenological studies. The lack of consistent patterns of responses among the four species (e.g. fruiting delayed two months in P. clavatum and advanced one month in M. acutiflora) suggests that climate change has unequal effects across tropical forests. This highlights the urgent need for further research to understand and forecast the ecological implications of these changes in global ecosystems processes.
面对最近的全球气候变化，物候事件的变化已被广泛记录。这些研究集中在温带植物上，而热带物种的反应仍知之甚少，这可能是由于热带地区缺乏长期的物候记录。在这种情况下，使用植物标本馆标本在长时间和广泛的地理区域内收集物候数据已成为一种强大的工具。在这里，我们使用四种巴西大西洋森林特有物种的 Melastomataceae 来评估物候模式和变化，以作为对最近气候变化的响应。物候数据是从 Reflora Virtual Herbarium 标本中收集的，这些标本是在 1920 年至 2018 年间采集的，并应用循环统计分析了 1920-1979 年、1980-1999 年和 2000-2018 年的间隔。使用多元线性回归测试了温度范围、平均温度、降水和光周期对每个物种开花和结果的影响。通过循环统计，我们检测到 Miconia quinquedentata、Pleroma clavatum 和 P. trichopodum 的开花以及 M. acutiflora、P. clavatum 和 P. trichopodum 的结果发生了变化，主要是延迟。我们还发现，开花和结果的发生与采集前几个月的当地气候条件有关。我们发现几十年来物候发生了明显的变化，而且这些变化与全球气候变化有关，这增加了来自高纬度地区的大量证据。我们的结果还支持植物标本馆收藏作为长期热带物候研究的重要来源。四个物种之间的响应模式缺乏一致性（例如，P. clavatum 的结果延迟了两个月，而 M. acutiflora 的结果提前了一个月）表明，气候变化对热带森林的影响是不平等的。这突显出需要进一步研究以了解和预测这些变化对全球生态系统过程的生态影响。
