Allee effects within small populations of Aconitum napellus ssp. lusitanicum, a protected subspecies in northern France.
Allee effects within small populations of Aconitum napellus ssp. lusitanicum, a protected subspecies in northern France.
复制标题
乌头小种群内的 Allee 效应。
作者：
Solenn Le Cadre;T. Tully;S. Mazer;Jean;J. Moret;N. Machon
由于花粉限制，低密度生长的植物可能会受到阿利效应的影响。先前对阿利效应的研究主要集中在种群规模或密度变化对繁殖的影响。在这里，我们在一种稀有植物乌头 (Aconitum napellus ssp) 中探讨了种群内植物分布对健康成分的影响。 lusitanicum 以及这些影响背后的生态和遗传机制已被确定。为了检测花粉限制，对自然斑块中不同大小的花序进行自然授粉和人工授粉下的种子产量进行比较，这些花序的花密度不同，并且与其他斑块的隔离程度不同。还比较了低密度和高密度斑块中产生的种子的发芽率和幼体存活率。补充花粉的花朵总是比开放授粉的花朵产生更多的种子，特别是在小型植物和低密度生长的植物中。低密度斑块中产生的后代表现出比高密度斑块中产生的后代更低的适应性。这可能是由受精后机制引起的，包括近交衰退或母体资源分配差异。这些结果表明，Allee 对适应度成分的影响（生态和遗传 Allee 效应）发生在不同空间尺度的 A. napellus 种群中。植物的空间分布似乎是影响繁殖产量和适应性的关键因素。
Plants growing at low density can suffer from Allee effects as a result of pollen limitation. Previous studies of Allee effects have focused on the effects of variation among populations in size or density on reproduction. Here, the effects of plant distribution within populations on fitness components are explored in a rare plant, Aconitum napellus ssp. lusitanicum, and ecological and genetic mechanisms underlying these effects are identified. To detect pollen limitation, seed production was compared under natural versus hand-supplemented pollinations on inflorescences of different sizes in natural patches differing both in flower density and in isolation from other patches. Germination rate and juvenile survival of seeds produced in low- and high-density patches were also compared. Pollen-supplemented flowers always produced more seeds than open-pollinated flowers, especially among small plants and plants growing at low density. Offspring produced in low-density patches exhibited lower fitness that those produced in high-density patches. This could have been caused by post-fertilization mechanisms, including inbreeding depression or differential maternal resource allocation. These results show that Allee effects on fitness components (ecological and genetic Allee effects) occur within A. napellus populations at different spatial scales. The spatial distribution of plants seems to be a crucial factor affecting reproductive output and fitness.