Conserving Slow‐Growing, Long‐Lived Tree Species: Input from the Demography of a Rare Understory Conifer, Taxus floridana
Conserving Slow‐Growing, Long‐Lived Tree Species: Input from the Demography of a Rare Understory Conifer, Taxus floridana
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保护生长缓慢、寿命长的树种：来自稀有林下针叶树佛罗里达红豆杉的人口统计数据
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发表时间：
2004
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影响因子：
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通讯作者：
W. Platt
中科院分区：
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作者：
C. Kwit;C. Horvitz;W. Platt
翻译后摘要：虽然土地保护和促进成功的再生是重要的保护行动，他们的能力，以增加人口增长率的缓慢增长，长寿的树木是有限的。 我们调查了佛罗里达红豆杉的种群数量，一种稀有的林下针叶树，分布在佛罗里达北方沿阿巴拉契科拉河布拉夫斯的沿着不同峡谷森林的三个种群中。我们通过使用四年的幼苗和已建立茎的招募和存活数据以及死茎横截面的直径生长数据，研究了人口参数和预测种群增长率的空间和时间模式。与其他年份相比，1996年所有种群的幼苗补充量都增加了大约10倍。8 ~ 16 mm的幼苗和茎的命运在种群间存在差异。其他两种尺寸类别（2 - 4 mm类别和4 - 8 mm类别）的股骨柄的结局在两个人群和年份之间存在差异。所有种群中的个体茎表现出相似的缓慢生长速率。随机矩阵模型预测所有人群的下降。随机矩阵分析揭示了高弹性的随机人口增长率的措施，在所有人口的大生殖干的停滞扰动。其他分析还表明，偶尔出现的高招募率不会对人口增长率产生很大影响。保护工作针对长寿，生长缓慢的稀有植物，如佛罗里达红豆杉，既要保护已建立的生殖个体，又要进一步提高处于其他生活史阶段的个体的存活率，如青少年，这通常不会对人口增长率做出很大贡献。
Abstract: Although land preservation and promotion of successful regeneration are important conservation actions, their ability to increase population growth rates of slow‐growing, long‐lived trees is limited. We investigated the demography of Taxus floridana Nutt., a rare understory conifer, in three populations in different ravine forests spanning its entire geographic range along the Apalachicola River Bluffs in northern Florida (U.S.A.). We examined spatial and temporal patterns in demographic parameters and projected population growth rates by using four years of data on the recruitment and survival of seedlings and established stems, and on diameter growth from cross‐sections of dead stems. All populations experienced a roughly 10‐fold increase in seedling recruitment in 1996 compared with other years. The fates of seedlings and stems between 8 and 16 mm differed among populations. The fates of stems in two other size classes (the 2‐ to 4‐mm class and the 4‐ to 8‐mm class) differed among both populations and years. Individual stems in all populations exhibited similarly slow growth rates. Stochastic matrix models projected declines in all populations. Stochastic matrix analysis revealed the high elasticity of a measure of stochastic population growth rate to perturbations in the stasis of large reproductive stems for all populations. Additional analyses also indicated that occasional episodes of high recruitment do not greatly affect population growth rates. Conservation efforts directed at long‐lived, slow‐growing rare plants like Taxus floridana should both protect established reproductive individuals and further enhance survival of individuals in other life‐history stages, such as juveniles, that often do not appear to contribute greatly to population growth rates.