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首页> 外文学位 >Reproduction, Demography, and Habitat Characterization of Astragalus peckii (Fabaceae), a Rare Central Oregon Endemic.
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Reproduction, Demography, and Habitat Characterization of Astragalus peckii (Fabaceae), a Rare Central Oregon Endemic.

机译：稀有俄勒冈州中部特有种黄芪（Fabaceae）的繁殖，人口统计学和栖息地特征。

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摘要

With little previous research on Astragalus peckii (Fabaceae), a state-listed Threatened species in Oregon, I investigated three facets of its biology which are integral to the conservation and management of the species. First, a four-year demographic study of two large populations revealed increasing population growth at one site (Chiloquin) and stable to declining population growth at another (Bull Flat). Both sites had varying levels of herbivory from a microlepidopteran larva, Sparganothis tunicana . Herbivore damage, regardless of when it occurred during the plant growing season, was correlated with increased plant mortality at Bull Flat but not Chiloquin. At Chiloquin, greater moth damage was correlated with decreased reproduction, particularly when the moth was active earlier in the growing season. These reductions in plant vital rates did not appear to contribute to negative population growth at either site. Rather, below-average precipitation levels during the growing season could be correlated with periods of population decline.;From a series of experiments on the reproductive biology of A. peckii, fruit and seed set were generally not limited by the quantity of pollen delivered by pollinators. Instead, high levels of seed abortion prevented most ovules from fully developing to seed. Quality of pollen (self-versus cross-pollen) also did not limit reproduction under natural pollination levels, but self-pollen reduced seed set, and to a lesser degree fruit set, during one of two years of hand-pollination experiments. Possible explanations for the treatment effect, including procedural causes, are discussed. Significant inbreeding depression was evident in the growth of greenhouse-grown seedlings but no statistical differences were found for seed germination or seedling survival. In order to minimize inbreeding depression in the field, adequate sizes of plant and pollinator populations need to be maintained.;Finally, using vegetation, habitat, climate, and soil data in a habitat model, greater A. peckii abundance was correlated with patches of low litter and soil crust cover within sites. Supporting these model results, greenhouse-grown seedlings with 1 cm of juniper litter on the soil surface had lower survival than those grown with less or no litter. There were no strong vegetation associations for A. peckii, though, indicating that within its restricted geographical range, A. peckii can be found in a diversity of plant habitats that have low litter cover.
机译：以前对俄勒冈州的一种濒危物种黄芪（Fabaceae）的研究很少，我研究了其生物学的三个方面，这些方面对于该物种的保护和管理至关重要。首先，一项针对两个大种群的四年人口统计学研究显示，一个地点的人口增长不断增加（Chiloquin），而另一个地点的人口增长却稳定到下降（公牛扁平化）。两个地点的鳞翅目昆虫均来自微鳞翅目幼虫Sparganothis tunicana。草食动物的损害，无论在植物生长季节何时发生，都与Bull Flat的植物死亡率增加相关，而与Chiloquin无关。在Chiloquin，蛾的危害更大与繁殖能力的降低有关，特别是当蛾在生长季节较早时活跃时。这些植物活力率的降低似乎并未导致两个地点的种群负增长。相反，生长季节降水量低于平均水平可能与种群下降时期有关。;从一系列有关啄木拟人生殖生物学的实验中，果实和结实种子通常不受制于花粉输送量的限制。传粉者。相反，高水平的种子流产阻止了大多数胚珠完全发育为种子。花粉的质量（自交花粉相对于异花粉）也没有限制自然授粉水平下的繁殖，但在两年的人工授粉实验之一中，自花粉减少了种子结实，并降低了结实程度。讨论了对治疗效果的可能解释，包括程序原因。在温室生长的幼苗的生长中有明显的近交抑制作用，但是对于种子发芽或幼苗存活没有统计学差异。为了最大程度地减少野外近亲繁殖的衰退，需要保持足够的植物和传粉媒介种群数量。最后，在栖息地模型中使用植被，栖息地，气候和土壤数据，将较高的拟南芥丰度与斑块的相关性联系起来。场地内的垫料和土壤结皮较低。支持这些模型结果的是，在土壤表面上生长杜松凋落物1厘米的温室种植的幼苗，其存活率要低于没有或没有凋落物的幼苗。但是，没有很好的植被相关性，表明在有限的地理范围内，可以在凋落物覆盖率低的多种植物栖息地中发现啄木鸟。

著录项

  • 作者

    Martin, Elizabeth F.;

  • 作者单位

    Oregon State University.;

  • 授予单位 Oregon State University.;
  • 学科 Botany.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 120 p.
  • 总页数 120
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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