鼠类对辽东栎橡子的搬运

在北京东灵山地区,在灌丛、森林2 种生境类型中共设计了5 个处理,以检验种子质量、种子可视度、生境类型如何影响鼠类对辽东栎（Quercus liaotungensis）橡子的搬运。每个处理包括200 枚种子。每日检查种子状态,实验持续16 d。鼠类在几天之内将大多数种子搬运走。完好橡子比虫蛀橡子消失得快。橡子在森林生境中明显比在灌丛生境中消失的快。鼠类对放置在灌丛下方和灌丛之间的橡子的搬运速率差别不大。放置在落叶下方的橡子消失速率明显慢于地表的橡子。本研究利用半存活时间测量种子的搬运率。各处理的半存活时间范围是0. 6 ～ 8. 6 d。各处理的橡子搬运率均较高,这说明鼠类有能力在种子下落到冬季来临的2 个月时间内,搬运绝大多数的橡子。实验说明,鼠类是辽东栎橡子重要的捕食者和扩散者。     

都江堰地区灌丛内袍栎橡子的捕食和搬运

从2000年9月至2002年12月,以四川都江堰常绿阔叶林灌丛内的优势种--枹栎(Quercus serrata)为研究对象,研究了昆虫、鼠类和真菌对枹栎橡子的捕食和搬运.结果表明(1)取食橡子的鼠类的群落结构和数量在年间差异较小,这可能与三年间袍栎橡子的产量相对稳定有关;(2)袍栎橡子的虫蛀率在三年间存在显著性差异,范围在14.17%-32.49%之间;(3)鼠类的就地取食和搬运是影响种子库内橡子命运的主要因素;(4)橡子虫蛀率的变化影响鼠类的觅食活动.鼠类对饱满橡子和虫蛀橡子的选择性取食和搬运可能影响许多坚果植物(栎树)的自然更新过程[动物学报50(4)535-540,2004].     

都江堰地区灌丛内迺栎橡子的捕食和搬运(英文)

从 2 0 0 0年 9月至 2 0 0 2年 1 2月 ,以四川都江堰常绿阔叶林灌丛内的优势种———栎 (Quercusserrata)为研究对象 ,研究了昆虫、鼠类和真菌对栎橡子的捕食和搬运。结果表明 :(1 )取食橡子的鼠类的群落结构和数量在年间差异较小 ,这可能与三年间栎橡子的产量相对稳定有关 ;(2 )栎橡子的虫蛀率在三年间存在显著性差异 ,范围在 1 4 1 7% - 32 4 9%之间 ;(3)鼠类的就地取食和搬运是影响种子库内橡子命运的主要因素 ;(4 )橡子虫蛀率的变化影响鼠类的觅食活动。鼠类对饱满橡子和虫蛀橡子的选择性取食和搬运可能影响许多坚果植物 (栎树 )的自然更新过程     

都江堰地区灌丛内枹栎橡子的捕食和搬运

从2000年9月至2002年12月,以四川都江堰常绿阔叶林灌丛内的优势种——枹栎(Quercus serrata)为研究对象,研究了昆虫、鼠类和真菌对枹栎橡子的捕食和搬运。结果表明：(I)取食橡子的鼠类的群落结构和数量在年间差异较小,这可能与三年间枹栎橡子的产量相对稳定有关;(2)枹栎橡子的虫蛀率在三年间存在显著性差异,范围在14．17％-32．49％之间;(3)鼠类的就地取食和搬运是影响种子库内橡子命运的主要因素;(4)橡子虫蛀率的变化影响鼠类的觅食活动。鼠类对饱满橡子和虫蛀橡子的选择性取食和搬运可能影响许多坚果植物(栎树)的自然更新过程[动物学报50(4)：535-540,2004]。     

外果皮厚度和种子大小对五种栎属橡子扩散的影响

动物对种子的扩散和贮藏是一个复杂的生态学过程,常常受到种子特征的影响。有关种子特征如何影响动物对种子扩散,许多研究结果并非完全一致。我们于2009 年9 月在黑龙江东方红林场野外和围栏内释放五种栎属橡子(Quercus mongolica,Q.serrata var. brevipetiolata,Q. aliena,Q.variabilis 和Q. liaotungensis),研究种子特征对鼠类(Apodemus peninsulae, Clethrionomys rufocanus 和Tamias sibiricus)扩散和埋藏橡子的影响。野外释放结果表明:橡子大小和外果皮厚度显著影响鼠类对橡子的扩散和埋藏。鼠类偏向扩散和埋藏种皮厚的大橡子,种皮薄的小橡子则多被原地取食。种皮厚的大橡子扩散距离显著高于种皮薄的小橡子。然而,只有外果皮的厚度显著影响围栏内花鼠对橡子的扩散和埋藏,橡子大小并非主要的影响因素。种子特征影响种子扩散的效应可能在种群和群落水平上存在差异。     

我国橡子资源开发利用现状与对策

在总结前人研究成果及作者实地调查的基础上,论述了我国,尤其是陕南秦巴山区的汉中地区橡子资源的植物物种来源和分类,并调查分析了我国橡子及橡子食品的营养、功能及安全特性、橡子资源的开发利用和橡子淀粉加工技术现状。指出了我国目前橡子资源开发利用存在的主要问题,并提出了解决措施。     

槲栎超寄生橡子内象甲幼虫的适应对策

栎属植物的橡子常常受到象甲的侵害, 对橡子存活产生影响, 但有关橡子对象甲幼虫适合度影响的研究尚未见报道。本研究旨在通过对槲栎Quercus aliena种子雨进程以及象甲幼虫逃逸过程的调查, 研究二者之间的进化适应关系。结果表明： 当年槲栎的种子产量为51.92±29.26粒/m², 虫蛀率达到42.4%。虫蛀的橡子中65%以上被象甲超寄生, 且显著大于完好的橡子。在种子下落过程中, 早期从橡子中逃逸的象甲幼虫要比后期逃逸的大。对某一超寄生的橡子而言, 首先逃逸出的象甲幼虫要比随后逃逸的幼虫大。另外, 从早期脱落的橡子中逃逸的幼虫明显小于后期脱落的橡子。象甲幼虫的干重随着橡子内象甲幼虫数量的增加而显著下降。象甲幼虫寄生数量与橡子的长径和短径呈现明显的正相关关系。尽管超寄生降低了象甲虫的适合度, 但雌性成体象甲产卵过程中偏好选择大橡子在一定程度上可以减少这种不利影响。因此, 小橡子可能更容易逃脱象甲的超寄生而获得较大的存活机会。     

锐齿槲栎橡子埋藏深度对发芽、幼苗出土和发育的影响

锐齿槲栎（Quercus aliena var.acuteserrata Maxim.)林内活动的许多型哺乳动物和鸟类不仅采食橡子,而且还常窖贮或在土壤大量的橡 子以便季后利用。这些埋藏的橡子构成了发育有效更新苗的主要种子来源。橡子被埋藏的深度和橡子的大小对幼苗的发育有潜在的影响。把橡子埋藏在6、12和18cm3个土层深度的实验结果显示：随着埋藏深度的增加,橡子的发芽率和发芽橡子的幼苗出土率都有明显下降,由深埋橡胶子发育的幼苗出土比较困难,所需时间较长,也更易腐烂,橡子的大小对发芽和幼苗出土没有明显的影响,早出土幼苗在第一个生长季内由于有较长的生长发育期,季末发育得较好,所以,由浅埋橡子发育的幼苗在更新成功方面有优势。     

“橡子新用途的研究”通过部级鉴定

1987年9月4日由商业部科技司委托吉林省供销社主持,在敦化市召开了“橡子新用途研究”的小试鉴定会。与会代表来自大专院校、科研及生产单位共22人,敦化市吴副市长也参加了会议。会议听取了项目承担单位商业部南京野生植物综合利用研究所沈卓群工程师和长春八十二中学江集远工程师关于“橡子新用途研究”的研制报告和应用报告。与会专家一致认为橡子是我国极为丰富的野生植物淀粉资源,通过多年的应用性研究,为橡子的开发利用找到了     

橡子淀粉的脱涩增白试验

橡子淀粉的脱涩增白试验李萱,宋扬（合肥三中,安徽省生物研究所）橡子是山毛榉科多种植物的坚果的俗称,橡子中淀粉含量约７０％左右,常被用来提取淀粉。山毛榉科在我国分布较广,除西北和西南地区较少外,在其他地区均广泛分布,因此,橡子可作为一种广泛的淀粉来源应...     

昆虫寄生对辽东栎种子命运的影响

报道了昆虫寄生对辽东栎 Quercus liaotungensis 种子命运的影响。结果表明：（1）被昆虫寄生的种子发芽率明显低于正常成熟的种子,被昆虫寄生的种子或者不能发芽,或者能发芽但随后死亡;（2）从虫卵到老龄幼虫的发育在橡实内完成,当橡实落地后幼虫破壳而出,整个种子库的幼虫破壳时间延续2～50天,并非高度同步化;种子库的虫寄生率高达45.4%,以柞栎象Curculio dentipes为主,还有少量其它种类,如另一种象虫Curculio sp.、栗白小卷蛾 Cydia kurokoi 和螟蛾科（Pyralidae）的一未定名种;（3）昆虫寄生影响橡实成熟,测量种子大小分布表明,被昆虫寄生的种子的大小分布介于未成熟和成熟种子之间;（4）象虫寄生取食引起16.05% 的种子能量损失,显著低于对照组。结果证明昆虫寄生对辽东栎种子的命运有重要影响,是影响辽东栎种群更新的关键因素之一。     

北京东灵山落叶阔叶林中辽东栎种子雨

在北京东灵山地区的一个落叶阔叶林中调查了辽东栎（Ｑｕｅｒｃｕｓ ｌｉａｏｔｕｎｇｅｎｓｉｓ Ｋｏｉｄｚ．）的种子雨。对于选定的４棵辽东栎中的３棵,树冠下的种子雨分布格局符合二次分布,具有很高的决定系数。由设置在树冠下的种子捕捉器收集的坚果数量来估计整棵树的种子雨。４棵树的种子雨中有活力的种子很少,变化范围从２６到２５９个。每棵树的树冠下的种子雨密度变化范围从０．７６到７．２６个／ｍ＾２。林中平均种     

Utilization of red oak acorns in non-bumper crop year

Utilization of acorns from individual red oaks Quercus rubra Fagaceae) was examined in the tree canopies during fall and from the ground beneath the canopies during winter in a Missouri oak-hickory forest. The goal of the study was to determine whether vertebrates show preference for acorns from individual trees on the basis of acorn or crop characteristics. Seed production, percentage of crop which was viable, maldeveloped, or infested by insects, average seed weight and tannin content of mature, viable acorns were measured for 11 red oak adults. Behavioral observations were conducted in September and October during the peak period of seed fall. Over winter removal was determined by counting the number of acorns removed from 3x3 m plots underneath the trees' canopies between December and mid-April. Canopy removal of acorns was surprisingly low-an estimated average of 52 acorns per tree compared with a mean estimated crop size of approximately 1,200 mature acorns. Over winter, approximately 50% of the acorns were removed from ground plots (range 7% to 93.1%). Number removed corresponded more to the density of nuts rather than to seed and crop characteristics. The low rate of acorn utilization by canopy visitors contrasts with other studies in the literature and may have been due to 1) the fact that this study was done in a relatively homogeneous forest where high density of conspecifics reduces the impact on any one individual or 2) perhaps an unusually low density of birds and mammals.     

啮齿动物鉴别虫蛀种子的能力及其对坚果植物更新的潜在影响

作为种子捕食者和种子扩散者, 啮齿动物对产坚果植物的自然更新有很大作用。然而, 对啮齿动物鉴别虫蛀种子的能力颇有争议。2001 年秋季在中国四川都江堰市实验林场, 以3 种比例(I₁∶S = 1∶1 , I₁∶S = 4∶1 和I₁∶I₂∶S = 1∶1∶1)供给啮齿动物4 种壳斗科种子: 栓皮栎( Quercus variabilis) 、枹树( Q. serrata) 、青冈( Cyclobalanopsis glauca) 和栲树( Castanopsis fargesii) 的3 种坚果型(即饱满种子(S) , 不含象虫的虫蛀种子(I₁) 和含象虫的虫蛀种子( I₂ ) 验证了啮齿动物能够准确地鉴别虫蛀种子这一假说。结果表明, 在3 种比例下4 种坚果的虫蛀种子的消失速率均慢于饱满种子。即使虫蛀种子的比例增加, 啮齿动物显著地搬走了更多的饱满种子(67%～92%) 。当虫蛀种子的比例增加时, 虫蛀种子就地消耗和拒绝的比例降低, 搬走比例增加。啮齿动物并不拒绝虫蛀种子, 这可能与它们的可利用性(如象虫可以作为蛋白质的补充) 和数量以及它们的觅食行为有关。结果证实啮齿动物能准确地鉴别虫蛀种子, 从而有区别地搬走并贮藏更多的饱满种子, 消耗一部分可以利用的虫蛀种子(包括其内的象虫) 。这样, 啮齿动物通过对饱满种子和虫蛀种子的鉴别和选择会影响不同种子的命运, 从而对这些坚果植物的自然更新产生影响。     

包衣、埋藏的栓皮栎和枹栎种子在鼠类捕食下的存留

鼠类对壳斗科植物种子的捕食作用十分强烈,从而影响此类植物的更新.栓皮栎和枹栎是中国西南地区常绿阔叶林主要树种,不仅有重要的经济价值,而且还可用于植树造林.对栓皮栎和枹栎种子分别进行包衣地表、无包衣地表、包衣埋藏和无包衣埋藏等4种处理,并跟踪各种处理种子被鼠类捕食的情况.结果表明:各处理之间种子的中位存留时间显著不同,包衣埋藏后的种子存留时间显著长于未包衣且放置于地表的种子,埋藏显著地降低了鼠类对这2种种子的捕食;埋藏及包衣处理能够很好地保护栓皮栎和枹栎种子免于鼠类的捕食,有利于种子存留并萌发建成幼苗.该方法可用于人工播种造林以提高造林成活率.     

Acorns containing deeper plumule survive better: how white oaks counter embryo excision by rodents

Several squirrel species excise the embryo of acorns of most white oak species to arrest germination for long‐term storage. However, it is not clear how these acorns counter embryo excision and survive in the arms race of coevolution. In this study, we simulated the embryo excision behavior of squirrels by removing 4 mm of cotyledon from the apical end of white oak acorns differing in embryo depths to investigate the effects of embryo excision on acorn germination and seedling performance of white oak species. The embryo depth in the cotyledons was significantly different among white oak acorns, with Quercus mongolica containing the embryo most deeply in the acorns. We found that artificial embryo excision significantly decreased acorn germination rates of Quercus variabilis, Quercus acutissima, Quercus aliena, Quercus aliena var. acutiserrata, Quercus serrata. var. brevipetiolata but not Q. mongolica. Artificial embryo excision exerted significant negative impacts on seedling performance of all oak species except Quercus aliena. Our study demonstrates the role of embryo depth of acorns in countering embryo excision by squirrels and may explain the fact that squirrels do not perform embryo excision in acorns of Q. mongolica with deeper embryos. This apparent adaptation of acorns sheds light on the coevolutionary dynamics between oaks and their seed predators.     

Multi-trophic effects of ungulate intraguild predation on acorn weevils

Predators and parasitoids may contribute to controlling the population sizes of phytophagous insects, and this has been shown to benefit plants. Phytophagous insects may also be killed by other herbivores (intraguild predation), usually larger-sized vertebrates that ingest insects accidentally while feeding on common food sources. We studied the intraguild predation on acorn weevils by ungulates and assessed the consequences for weevil populations. Infested acorns are prematurely abscised and the weevil larvae finish their development inside the acorns after being dropped. Our results show that weevil larvae were killed by ungulates eating the infested acorns on the ground. Ungulates did not discriminate between infested and sound acorns, and the probability of a larva being incidentally eaten was inversely related to acorn availability. Thus, predation risk was enhanced by the premature drop of infested acorns when acorn availability on the ground was low. Predation rates on infested acorns were much higher where ungulates were present, and acorn infestation rates were significantly lower. However, ungulates did not provide the oaks any net benefit, since the reduction of infestation rates was not enough to compensate for the large amounts of sound acorns eaten by ungulates. Seed predation is usually studied as a progressive loss of seeds by pre- and post-dispersal predators, but the interactions between them are usually not considered. We show that intraguild predation on insects by large ungulates had an effect on the structure of the foraging guild, as the proportion of acorns predated by insects decreased; however, replicating the same experimental design in different ecological scenarios would increase the strength of these results. In conclusion, the present study shows the importance of considering the multi-trophic interactions between seed predators in order to have a complete picture of granivory.     

Not only size matters: Acorn selection by the European jay (Garrulus glandarius)

A strong selection for acorn characteristics is expected to have evolved in the mutualistic relationship between the European jay (Garrulus glandarius) and the oak (Quercus spp.). Bossema's pioneer work suggested that jays do not select acorns randomly, but rather they preferentially select some size and species. Preference for some seeds over others may have implications on plant community dynamics by conferring advantages (or disadvantages) on the selected (avoided) seed characteristics. In this paper we test to what extent jays select acorns by species and/or by size and the relation between these two traits in Mediterranean oak species. The experiments consist of a set of field tests in which acorns from four different coexisting Mediterranean oak species (Quercus ilex, Quercus faginea, Quercus suber, and Quercus coccifera) were placed in artificial feeders accessible to wild jays. The acorns were previously measured to control individual acorn characteristics. Using video-recording techniques, we followed jay activity and the fate of each acorn (sequence of acorn selection and method of transport). Q. ilex acorns were preferred over other acorns, and Q. coccifera acorns were avoided when other acorns were available. Preference for Q. faginea and Q. suber acorns was intermediate, that is, they were preferred over Q. coccifera acorns but not over Q. ilex acorns. Large acorns were also preferred although acorn species selection was stronger than size selection. Jays selected species and size both by visual means and by using acorn area as an indicator of size. Acorns wider than 17–19 mm were carried in the bill because of throat limitation. Our results confirm Bossema's study on temperate oaks and extend it to Mediterranean oak species, revealing implications on mixed oak forest dynamics.     

Relation of ramet size to acorn production in five oak species of xeric upland habitats in south-central Florida

This study examined variation in two components of acorn production. Percentage of bearing ramets (stems) and number of acorns per bearing ramet were examined in five clonal oaks in three xeric habitats of south-central peninsular Florida in relation to ramet size within and between species and vegetative associations. Counts of acorns on two white oaks (Quercus chapmanii and Q. geminata) and three red oaks (Q. inopina, Q. laevis, and Q. myrtifolia) were conducted annually from 1969 to 1996 (except in 1991) on permanent grids in southern ridge sandhill, sand pine scrub, and scrubby flatwoods associations at the Archbold Biological Station, Florida, USA. Percentage of bearing individuals and mean number of acorns per bearing individual increased with increasing ramet size for all species across all vegetation associations. However, in Q. geminata and Q. myrtifolia, acorn production declined in the largest size class (>3.2 m), implying that larger individuals of these clonal species may become senescent. All oak species in sand pine scrub, which had a nearly closed overstory, had lower frequencies of bearing oaks and mean numbers of acorns compared with similar-sized individuals of the same species in the more open-canopied southern ridge sandhill and scrubby flatwoods associations, suggesting light limitation. The annual production of acorns by a given oak species was correlated across vegetative associations and annual acorn production of oak species was correlated for species within the same section. Intermediate-size class oaks contributed the most acorns per unit area, suggesting that stands managed with short fire-return times will provide fewer acorns to wildlife than stands managed to produce more variable distributions of oak size classes. However, our study suggests that long-unburned stands, such as those studied here, will maintain relatively constant levels of acorn production as a consequence of ramet replacement within the clones of these shrubby oaks to create a variable distribution of size classes. Of the oak species studied, Q. myrtifolia had the highest acorn production and the smallest acorns, while Q. laevis had the lowest acorn production and the largest acorns, suggesting an allocation trade-off between acorn numbers and size.