Abstract:
Thermophilization is the directional change in species community composition towards greater relative abundances of species associated with warmer environments. This process is well-documented in temperate and Neotropical plant communities, but it is uncertain whether this phenomenon occurs elsewhere in the tropics. Here we extend the search for thermophilization to equatorial Africa, where lower tree diversity compared to other tropical forest regions and different biogeographic history could affect community responses to climate change. Using re-census data from 17 forest plots in three mountain regions of Africa, we find a consistent pattern of thermophilization in tree communities. Mean rates of thermophilization were +0.0086 °C·y-1 in the Kigezi Highlands (Uganda), +0.0032 °C·y-1 in the Virunga Mountains (Rwanda-Uganda-Democratic Republic of the Congo) and +0.0023 °C·y-1 in the Udzungwa Mountains (Tanzania). Distinct from other forests, both recruitment and mortality were important drivers of thermophilzation in the African plots. The forests studied currently act as a carbon sink, but the consequences of further thermophilization are unclear.
摘要:
嗜热是物种群落组成向与温暖环境相关的物种相对丰度增加的方向变化。这个过程在温带和新热带植物群落中有很好的记录,但是不确定这种现象是否发生在热带其他地方。在这里,我们将对嗜热的搜索扩展到赤道非洲,与其他热带森林地区相比,树木多样性较低以及不同的生物地理历史可能会影响社区对气候变化的反应。利用非洲三个山区17个森林地块的再普查数据,我们在树木群落中发现了一致的嗜热模式。Kigezi高地(乌干达)的平均嗜热速率为0.0086°C·y-1,维龙加山脉(卢旺达-乌干达-刚果民主共和国)的0.0032°C·y-1和乌宗格瓦山脉(坦桑尼亚)的0.0023°C·y-1。与其他森林不同,招募和死亡率都是非洲地块高温化的重要驱动因素.目前研究的森林充当碳汇,但进一步热灭菌的后果尚不清楚。