Tree Seed Production and Food Conditions for Rodents in an Oak Wood in Southern England
Tree Seed Production and Food Conditions for Rodents in an Oak Wood in Southern England
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英格兰南部橡树林中的树木种子生产和啮齿动物的食物条件
DOI：
10.1093/forestry/66.3.291
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发表时间：
1993
期刊：
影响因子：
2.8
通讯作者：
J. Gurnell
中科院分区：
文献类型：
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作者：
J. Gurnell
1975 年至 1988 年间，对英格兰南部的橡树 (Quercus robur) 树林中的种子产量和种子损失进行了监测。除了橡子之外，还监测了树林中生长的几种大型山毛榉 (Fagus sylvatica) 和甜板栗 (Castanea sativa) 树以及榛树 (Corylus avellana) 树下层的种子。这四种树种的种子都受到啮齿动物以及鸟类和昆虫等其他食种子动物的严重捕食。种子的掉落往往不规律，1976年、1985年和1987年这三年被认为是橡树肥大年。橡子大丰收的年份太少，无法检验这些年份的资源枯竭是否导致随后几年的歉收。四种树种之间的种子产量没有相关性，这与捕食者捕食行为的捕食者饱和理论的预测之一不相符。研究了天气对种子生产的影响，但几乎没有发现显着的相关性。总的来说，结果倾向于支持之前的发现。 1980 年至 1982 年间，木材内爆发了严重的卷蛾毛虫疫情，可能影响了橡子的生产。研究发现，橡树落叶与第二年的橡子产量之间存在负相关关系。最初，森林地面的种子流失速度很快，在 9 年内没有种子存活到下一年，而且食粮动物的食物条件很差。在剩下的四年中，有三年橡子一直存活到春季和初夏，为森林啮齿动物提供良好的食物条件，直到替代食物供应出现为止。尽管橡树在丰年时贡献了大部分种子能量，但其他树种，尤其是山毛榉，在橡子产量不佳时变得重要。由于捕食者造成的扩散前损失通常很高，榛树、甜栗树、橡树和山毛榉的平均损失分别为 80%、40%、38% 和 33%。平均而言，榛子往往首先掉落，比橡子早大约 6 周，而橡子往往是这四种树种中最后掉落的种子。诺珀瘿和象鼻橡子比健全的橡子掉落得早。一项关键因素分析表明，成熟失败、扩散前的捕食以及象鼻虫和诺珀瘿的昆虫侵扰对橡子数量的逐年变化同样有影响。
Seed production and seed losses were monitored in an oak (Quercus robur) wood in southern England between 1975 and 1988. In addition to acorns, seeds from several large beech (Fagus sylvatica) and sweet chestnut (Castanea sativa) trees which occurred within the wood, and from the understorey of hazel (Corylus avellana) trees, were also monitored. The seeds from these four tree species are all subject to heavy predation by rodents, as well as other seed-eaters such as birds and insects.Seed fall tended to be irregular and three years, 1976, 1985 and 1987 were considered oak mast years. There were too few years with large acorn crops to examine whether resource depletion in these years resulted in poor crops in subsequent years. There was no correlation in seed production between the four tree species which does not agree with one of the predictions of the predator satiation theory of masting behaviour. The effects of weather on seed production were investigated but few significant correlations were found. In general the results tended to support previous findings. Between 1980 and 1982 a serious outbreak ofTortrixmoth caterpillars occurred within the wood and may have affected acorn production. A negative relationship was found between oak defoliation and acorn production in the subsequent year.The loss of seeds from the forest floor was initially rapid and in 9 years no seeds survived into the following year and food conditions were poor for granivores. In 3 of the remaining 4 years acorns survived well into spring and early summer providing good food conditions for forest rodents through to the times when alternative food supplies became available. Although oak trees contributed most seed energy in good years, the other tree species, especially beech, became important when acorn production was poor. Predispersal losses due to predators were frequently high and averaged 80 per cent, 40 per cent, 38 per cent and 33 per cent in hazel, sweet chestnut, oak and beech respectively. On average, hazel nuts tended to fall first, some 6 weeks before acorns which tended to be the last seeds to fall of the four tree species. Knopper galls and weeviled acorns fell earlier than sound acorns. A key-factor analysis indicated that a failure to mature, predispersal predation and insect infestation from weevils and Knopper galls contributed equally to changes in numbers of acorns among years.