Conservation ecology for coastal Persea thunbergii forests at northern limit

我在北界森林中考察了刺柏的萌发物候，并在苗圃中进行了完整的肉质果实和去髓种子的萌发实验。在封闭的林冠下，黄连木分散后不久，秋季很少出苗；大多数幼苗在第二年夏天发芽。相反，在森林边缘，许多幼苗在秋天和接下来的夏天出现。百分之二十的去浆种子在播种后不久的秋天发芽，尽管大多数有完整果肉的种子在接下来的夏天发芽。食果鸟类通过吞食将果肉从种子中除去，并将种子撒开。食果动物的去髓可能导致了黄杨萌发的二态性。70%的秋季苗木在第二年冬天或早春时枯死。而在30%的相对光子通量密度下，秋季应急苗的生长速度明显快于夏季应急苗。发芽二态性可能对幼苗在北部不可预测的冬季气候中存活很重要。

I examined the germination phenology of Persea thunbergii in the forest at the northern limit and conducted a germination experiment in a nursery using intact fleshy fruits and seeds with the pulp removed. Under a closed canopy of P. thunbergii, few seedlings emerged in autumn soon after their dispersal; most seedlings emerged in the following summer. In contrast, at the forest edges, many seedlings emerged in autumn as well as during the following summer. Twenty percent of the depulped seeds germinated in the autumn soon after sowing, although most of the seeds with pulp intact germinated during the following summer. Frugivorous birds remove the pulp from the seed by ingestion and scatter the seeds. Pulp removal by frugivores probably induces germination dimorphism of P. thunbergii. Seventy percent of autumn emergent seedlings died back the following winter or in early spring. However, the autumn emergent seedlings that escaped from dying back grew significantly faster than the summer emergent seedlings under a 30% relative photon flux density. Germination dimorphism may be important for seedling survival in the unpredictable winter climate at the northern limit.