Cone characteristics and insect predation levels vary across years in mast seeding white spruce
Cone characteristics and insect predation levels vary across years in mast seeding white spruce
复制标题
肥大播种白云杉的球果特征和昆虫捕食水平因年份而异
DOI：
10.1139/cjfr-2020-0442
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发表时间：
2021
影响因子：
2.2
通讯作者：
LaMontagne, Jalene M.
中科院分区：
文献类型：
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作者：
Leeper, Abigail C.;LaMontagne, Jalene M.
许多树种的种群表现出同步的和高度时变的种子作物。这种繁殖模式有两种主要的假设：授粉效率和种子捕食者的满足。桅杆播种研究通常涉及种群水平的繁殖记录，关于生殖结构特征的信息较少。在这里，我们使用了6年（2012-2017）的数据，跨越了一系列种群水平的球果条件，来表征(i)白云杉（Picea glauca(Moench) Voss）的球果长度和每个球果的种子，以及（ii）种子捕食水平。我们量化了种群水平的球果产量，并从美国密歇根州休伦山的38棵树中采集了1399个球果。线性混合模型表明，平均锥长和最小锥长在不同年份间变化显著；两者在球果产量最大的年份最长。更大的球果有更多的种子，关系的斜率以及截距在不同年份变化显著。广义线性混合模型和赤池信息准则模型选择结果表明，种群水平繁殖最低时，昆虫捕食损害最大的球果，当年平均受损比例为0.82。我们的研究结果表明，白云杉球果的特征和昆虫种子捕食的损失是有时间变化的，并且遵循基于桅杆播种假设的预期。
Populations of many tree species exhibit synchronous and highly temporally variable seed crops across years. This is called mast seeding, and there are two predominant hypotheses for this pattern of reproduction: pollination efficiency and seed-predator satiation. Mast seeding studies typically involve records of population-level reproduction, with less information on the characteristics of reproductive structures. Here, we use data across 6 years (2012–2017), spanning a range of population-level cone conditions, to characterize (i) white spruce (Picea glauca(Moench) Voss) cone lengths and seeds per cone, and (ii) levels of seed predation. We quantified population-level cone production and collected 1399 cones from a total of 38 trees in the Huron Mountains, Michigan, USA. Linear mixed models showed that mean and minimum cone lengths varied significantly across years; both being longest during the greatest cone production year. Larger cones had more seeds and the slopes of the relationships as well as the intercepts varied significantly across years. Generalized linear mixed models and Akaike’s information criterion model selection showed that cones with insect predation damage was greatest when population-level reproduction was the lowest, with a mean proportion of cones damaged 0.82 in that year. Our findings show that white spruce cone characteristics and losses to insect seed predation vary temporally, and follow expectations based on mast seeding hypotheses.