Garnier Suzon, Giordanengo Emma, Saatkamp Arne, Santonja Mathieu, Reiter Ilja M, Orts Jean-Philippe, Gauquelin Thierry, Meineri Eric
Aix Marseille Univ, Avignon Univ CNRS, IRD, IMBE Marseille France.
CNRS, ECCOREV Aix-en-Provence France.
Ecol Evol. 2021 Nov 10;11(22):16143-16152. doi: 10.1002/ece3.8295. eCollection 2021 Nov.
Seedling recruitment is a bottleneck for population dynamics and range shift. The vital rates linked to recruitment by seed are impacted by amplified drought induced by climate change. In the Mediterranean region, autumn and winter seedling emergence and mortality may have strong impact on the overall seedling recruitment. However, studies focusing on the temporal dynamic of recruitment during these seasons are rare. This study was performed in a deciduous Mediterranean oak forest located in southern France and quantifies the impact of amplified drought conditions on autumn and winter seedling emergence and seedling mortality rates of two herbaceous plant species with meso-Mediterranean and supra-Mediterranean distribution (respectively, and ). Seedlings were followed from October 2019 to May 2020 in both undisturbed and disturbed plots where the litter and the aboveground biomass have been removed to create open microsites. Amplified drought conditions reduced seedling emergence and increased seedling mortality for both species but these negative effects were dependent on soil disturbance conditions. Emergence of decreased only in undisturbed plots (-7%) whereas emergence of . decreased only in disturbed plots (-10%) under amplified drought conditions. The seedling mortality rate of . was 51% higher under amplified drought conditions in undisturbed plots while that of . was 38% higher in disturbed plots. Aridification due to lower precipitation in the Mediterranean region will negatively impact the seedling recruitment of these two species. Climate change effects on early vital rates may likely have major negative impacts on the overall population dynamic.
幼苗补充是种群动态和范围转移的一个瓶颈。与种子繁殖相关的生命率受到气候变化导致的干旱加剧的影响。在地中海地区，秋冬季节的幼苗出土和死亡率可能会对整体幼苗补充产生重大影响。然而，关注这些季节繁殖时间动态的研究很少。本研究在法国南部的一片落叶地中海橡树林中进行，量化了干旱加剧条件对两种具有中地中海和超地中海分布的草本植物（分别为 和 ）秋冬季节幼苗出土和幼苗死亡率的影响。从2019年10月到2020年5月，在未受干扰和受干扰的地块中跟踪幼苗，在这些地块中，凋落物和地上生物量已被清除以创建开阔的微生境。干旱加剧条件降低了两种植物的幼苗出土率并增加了幼苗死亡率，但这些负面影响取决于土壤干扰条件。在干旱加剧条件下， 的出土率仅在未受干扰的地块中下降（-7%），而 的出土率仅在受干扰的地块中下降（-10%）。在未受干扰的地块中，干旱加剧条件下 的幼苗死亡率高出51%，而在受干扰的地块中， 的幼苗死亡率高出38%。地中海地区降水减少导致的干旱化将对这两种植物的幼苗补充产生负面影响。气候变化对早期生命率的影响可能会对总体种群动态产生重大负面影响。
