东灵山地区啮齿动物群落组成及优势种群的季节变动

2000年9月和2001年9月在东灵山地区采用夹夜法对小型啮齿动物群落进行调查。共捕获啮齿动物6种,总捕获率为16．08％。大林姬鼠是该地区小型啮齿动物群落中的优势种。同时将8种生境样地划分为7类啮齿动物群落：即落叶松人工林大林姬鼠 社鼠群落、灌丛大林姬鼠 社鼠群落、辽东栎矮林大林姬鼠 大仓鼠群落、弃耕地大林姬鼠 黑线姬鼠群落、油松人工林大林姬鼠 社鼠群落、针润混交林大林姬鼠 社鼠群落、辽东栎林大林姬鼠 社鼠群落。群落间的相似性系数普遍较高,其中油松人工林大林姬鼠 社鼠群落和辽东栎林大林姬鼠 社鼠群落的相似性最高。灌丛大林姬鼠 社鼠群落的多样性指数和均匀性指数最高。     

啮齿动物对北京小龙门林场辽东栎地表种子的扩散

20 0 0年 9月至 10月在小龙门林场选取两块辽东栎林样地 ,在地表分别针对无脊椎动物 (处理 1)、啮齿动物和无脊椎动物 (处理 2 )、所有扩散者 (处理 3)、所有扩散者但具隐蔽性 (处理 4 )设置 4种试验处理 :两样地 4种处理各设置 0 5m× 0 5m的地表样方 5个 ,在样方内放置饱满和虫损辽东栎种子各 2 0粒 ,每样地全部样方共布放种子 80 0粒 ;4种处理的种子累计丢失情况共调查 9次。有网罩的处理 1无种子丢失 ;两样地处理 2和处理 3之间种子丢失量均无显著差异 (P >0 0 5 ) ;处理 2、 3种子丢失量均显著多于处理 4。在两样地中 ,不仅处理 2中饱满种子与虫损种子丢失量差异均显著 (样地 1:t =2 4 0 7,P <0 0 5 ;样地 2 :t =2 6 5 ,P <0 0 5 ) ,而且处理 3中亦然 (t=3 2 0 9,P <0 0 5 ;t =3 0 92 ,P <0 0 5 ) ;两样地中被啃咬的饱满种子都显著多于虫损种子 (χ2 =14 75 ,P <0 0 5 ;χ2 =9 85 ,P <0 0 5 )。标记重捕结果显示该地区啮齿动物群落包括朝鲜姬鼠等 4种小型哺乳动物 ,其中朝鲜姬鼠占啮齿动物群落的 74 4 %。以上结果说明该地区辽东栎种子主要扩散者是啮齿动物 ,鸟类和无脊椎动物对种子扩散无明显影响 ;地表微环境可降低种子被取食的几率 ;啮齿动物优先选择饱满种子 ,对种子质量有明显选     

东灵山辽东栎林啮齿动物群落组成及多样性

1999～ 2 0 0 1年采用标记重捕法对东灵山小龙门林场辽东栎林啮齿动物群落进行了 1 2次调查。共布 2 93 6笼日 ,捕得啮齿动物 2 68只 ,平均捕获率为 9%。啮齿动物群落包括三科四属 ,由朝鲜姬鼠(Apodemuspeninsulae)、社鼠 (Niviventerconfucianus)、棕背 (Clethrionomysrufocanus)和花鼠 (Eotamiassibiricus)组成 ,分别占群落的 85 5 %、8 6%、3 0 %和 2 6%;朝鲜姬鼠为优势鼠种。标记重捕调查表明朝鲜姬鼠重捕率无性别差异 (t =0 91 3 ,P >0 0 5 )。啮齿动物物种多样性指数和均匀度指数均呈“低 高 低”年间波动趋势 ,差异不显著 (t=0 1 65 ,P >0 0 5 ) ;生态优势度指数变化趋势反之 ,样地间无显著差异(t=0 0 64,P >0 0 5 )。可以认为该地区辽东栎林中啮齿动物群落结构较稳定。     

东灵山辽东栎虫损种子调查

2000年8月底至9月底,在北京东灵山地区小龙门林场对2块辽东栎样地中虫损种子下落动态进行了调查.结果表明:2块样地辽东栎种子产量分别高达19.15和91.23颗·m-2,而2块样地虫损种子较多,分别为49.23和33.38个·m-2,所占种子库比例分别为36.93%和25.96%;1999年研究发现(阎文杰,2000),2样地辽东栎种子产量为13.09和7.24颗·m-2,其中虫损种子产量为10.87和5.90颗·m-2,虫损率高达82.22%和75.43%.2年的观察结果均证实虫损种子在种子雨早期迅速下落,且低产年份的虫损种子在种子库中的比例显著高于高产年份.高比例的虫损种子可能是导致辽东栎实生苗更新率低的重要因素.     

埋藏和环境因子对辽东栎(Quercus liaotun-gensis Koidz)种子更新的影响

辽东栎萌生丛零散地分布在北京山区,虽然其种子量很大,但自然状况下的实生苗非常稀少。鼠类搬运并吃掉大量散落在地表的辽东栎种子,但鼠类是否影响辽东栎的自然更新尚不清楚。本研究主要在于了解：（1）将种子埋入土层内后对辽东栎种子出苗率的影响;（2）环境因子（如坡向、地表植被等）对辽东栎种子出苗率的影响。1996年9月24日,选取5块样地（Site）,在每块样地各设置1条样线（Transect),每条样线上设置若干样点（Plot）,样点间隔10m,用于种子埋藏实验,在每个样点设置6条平行线（Parallel transect),间隔10cm,各埋入10粒种子,种子间隔2cm;第1、2、3、4、5、6条线的埋藏深度分别为0、2、4、6、8、10cm。分别于1997年6月15日和10月4日调查出苗情况。研究结果表明,和秋季辽东栎种子出苗率均与埋藏深度呈正相关,埋藏通过改善湿度和减少鼠类等动物的取食而增加了出苗率,其贡献分别占18％和12％。但鼠类对埋入土层内种子的取食率依然很高（87％）。辽东栎种子在阴坡和阳坡的最终出苗率都很高,但阳坡地要早于阴坡。夏季辽乐栎种子出苗率均与地表植被覆盖度负相关,地表植被可能是通过与辽东栎种子竞争水分和养分而降低辽东栎种子出苗要早于阴坡。夏季辽东栎种子出苗率均与地表植被覆盖度和高度相关不显著,从夏季到秋季,从东栎种子出苗率有所增加,主要是由于埋藏在深处或阴坡处的种子出苗较晚的缘故。     

人工埋藏植物种子对鼠类采食下辽东栎坚果存活及萌发率的影响

辽东栎林（Q. liaotungensis)是北京东灵山地区典型地带植被。过去研究表明,鼠类对辽东栎更新有很大影响。本研究主要调查3个问题：（1）采食辽东栎坚果的鼠类种类;（2）将坚果埋藏于土中能否减少鼠类对坚果的采食,并提高出苗率？（3）地表植被是否影响辽东栎的出苗率？1996年9月在北京东灵山地区山地选取5个类型的样地37块,每样地在地表放置10粒坚果,检查地表种子消失率。使用木板夹来调查采食坚果的鼠类种类,诱饵分别为坚果和花生米。于1997年10月,选取5块样地,间隔25 m,每样地在1m²范围内埋50粒坚果,深度5 cm,次年5月调查出苗情况。研究结果表明,大林姬鼠、社鼠和黑线姬鼠为取食坚果的主要种类,取食比例与其丰富度有关。370粒坚果放在地表后,1d、10d、20d的消失率分别达15.1%、78.1%、和 100%。250粒坚果埋入土层后,出苗率达11.2%,苗平均高度为7.8cm,出苗率与地表植被盖度有一定负相关。本研究认为,人工埋藏植物种子可以减少鼠类捕食坚果,并能增加其出苗率。     

灌丛高度对啮齿动物贮藏和扩散辽东栎坚果的影响

本文选择高、矮两类灌丛生境, 于2002 年至2003 年在其中释放标记的辽东栎坚果, 并连续记录释放坚果的命运, 以了解生境差异对啮齿动物搬运、取食和贮藏辽东栎坚果的影响以及啮齿动物对微生境的选择等。研究结果表明, 大林姬鼠等啮齿动物对辽东栎坚果的短期取食非常强烈, 而分散贮藏的量则相对较少; 啮齿动物对辽东栎坚果的搬运距离在矮灌丛生境中显著大于高灌丛生境; 啮齿动物倾向于选择灌丛边缘和灌丛下方取食或贮藏辽东栎坚果, 这类微生境也有利于埋藏坚果的萌发。     

啮齿动物捕食压力下生境类型和覆盖处理对辽东栎种子命运的影响

在六盘山区的退化辽东栎灌丛和辽东栎次生林 (以下分别称“灌丛样地“和“次生林样地”),研究了群落生境和清除凋落物、凋落物覆盖及土壤覆盖等处理对啮齿动物取食和搬运/贮藏辽东栎种子的影响。结果表明：(1) 凋落物和土壤覆盖处理在种子释放的前期阶段有利于种子留存,但释放40天后,种子在释放点的最终留存率在灌丛样地显著高于次生林样地 (Z = -2.333, P = 0.020)。灌丛样地的自然状态的种子最终留存率显著高于凋落物覆盖处理 (Z = -0.674,P = 0.05),但其它处理间无显著差异;次生林样地的凋落物覆盖和清除凋落物处理种子的最终留存率为0%,自然状态和土壤覆盖处理均不足1%,各处理间无显著差异。(2) 种子被啮齿动物的就地取食率在不同群落生境间差异显著 (Z = -2.333,P = 0.020);在灌丛样地,凋落物覆盖处理种子被啮齿动物就地取食率最高 (45.56%),而次生林样地的土壤覆盖处理最高 (64.81%),种子被啮齿动物就地取食率在灌丛样地和次生林样地均为清除凋落物处理最低 (分别为23.70%和40.00%);生境类型和覆盖处理对种子搬运后的取食率均无显著影响。(3) 次生林样地种子被啮齿动物搬运后的埋藏率显著高于灌丛样地 (Z = -2.88,P = 0.004);在灌丛样地,土壤覆盖处理种子搬运后的埋藏率最高仅5.56%,而在次生林样地,清除凋落物处理最高达9.26%。(4) 种子被啮齿动物搬运后取食的距离在灌丛样地和次生林样地分别为3.01 m和2.13 m,差异显著 (Z = -2.080,P = 0.038),而种子搬运后的埋藏距离前者小于后者 (分别为1.35 m和2.10 m),两者间差异不显著。     

秦岭中段不同坡向锐齿栎种子雨、土壤种子库与幼苗更新

以秦岭中段不同坡向(阳坡、半阳坡、半阴坡及阴坡)锐齿栎天然林为对象,对锐齿栎种子雨、种子库的数量、质量动态以及幼苗发育过程进行研究.结果表明: 锐齿栎种子雨一般从8月中旬开始,9月中下旬到10月上旬达到高峰期,11月中上旬结束;不同坡向的种子雨降落历程、发生时间和组成不同;半阳坡种子雨强度最大,为134.13粒·m^-2,其余大小依次为阳坡、半阴坡、阴坡;阳坡种子雨降落时间最早、持续时间最长,高峰期持续时间也最长,阴坡种子雨降落时间最晚、持续时间最短,高峰期持续时间也最短;种子活力及成熟种子占其种子雨的比例大小顺序为半阳坡>阳坡>半阴坡>阴坡.从种子雨降落结束到翌年8月,各坡向土壤种子库总储量大小顺序均为半阳坡>阳坡>半阴坡>阴坡;各坡向的土壤种子库中成熟、未成熟、被啃食种子数量和种子活力均随时间变化呈递减趋势,而霉烂种子数量增加;各坡向土壤种子库中的种子均主要集中在枯落物层,其次为0~2 cm土层,而在2~5 cm土层中只有极少量种子存在.4种坡向中锐齿栎幼苗的密度差异显著,半阳坡幼苗最多,其余依次是阳坡、半阴坡和阴坡.半阳坡更适合锐齿栎种子的萌发和幼苗生长.     

鼠类对山杏和辽东栎种子的贮藏

在北京市东灵山地区,选择灌丛生境,人工释放山杏和辽东栎种子,对两种种子在释放处被鼠类就地取食、存留动态、种子被搬运和贮藏的距离、位置、状态、微生境等进行了分析比较。采用活捕饲喂和咬痕比较的方法,对野外取食山杏和辽东栎种子的鼠类进行了鉴定。结果表明：1)取食山杏和辽东栎种子的鼠类主要是大林姬鼠和岩松鼠;2)山杏种子被鼠类搬运的平均距离大于辽东栎种子,两种种子大多数被搬运至21m之内,在9m之内最为集中;3)山杏种子的中位存留时间较辽东栎种子长;4)在释放处,鼠类对辽东栎种子的就地取食强度(54．83％)大于对山杏种子的取食(0．17％);5)在搬运之后,大部分山杏种子被埋藏起来,仅有3粒被取食;而辽东栎种子大部分被取食;6)鼠类趋向于把种子搬运到灌丛下方或灌丛边缘进行贮藏或取食。山杏种子在贮藏点的数量为1—3粒,而辽东栎种子在贮藏点的数量均为1粒。     

种子产量对鼠类扩散栓皮栎坚果的影响

为了解林木种子产量对鼠类种子扩散行为的影响,于2008 年和2009 年,在国有济源市愚公林场调查了栓皮栎的种子雨;在每年的种子雨结束后,选择次生林生境,研究了鼠类对人工释放栓皮栎坚果的扩散,旨在探讨种子产量与种子扩散间的关系。结果表明:1)取食栓皮栎坚果的鼠类主要有大林姬鼠、社鼠和岩松鼠,2008 年的鼠类捕获率(2% )低于2009 年(10%),其差异并未达到显著性水平;2)栓皮栎的种子雨构成和产量存在年际差异,2008 年以完好种子为主且产量高于2009 年,而2009 年以败育种子为主;3)2008 年人工释放栓皮栎坚果的中位存留时间显著高于2009 年;4)2008 年鼠类对栓皮栎坚果的平均扩散距离显著低于2009 年,且两年的搬运距离几乎都集中在9 m 以内;5)2008 年鼠类对栓皮栎坚果的埋藏比例显著高于2009 年。结果提示,在种子高产年份,可能有较多的种子逃脱动物的取食,从而增加种子萌发和幼苗建成的机会,最终促进植物的更新。     

Spatial and Temporal Variation of Seed Rain in the Canopy and on the Ground of a Tropical Cloud Forest

Spatial and temporal patterns of seed rain impact plant fitness, genetic and demographic structure of plant populations, and species' interactions. Because plants are sessile, they rely on biotic and abiotic dispersal agents to move their seeds. The relative importance of these dispersal agents may shift throughout the year. In tropical forests, seed dispersal of epiphytes constitutes a major but hitherto unknown portion of seed rain ecology. For the first time, we report on patterns of seed rain for both epiphytic and terrestrial plants across an entire year in a Neotropical montane forest. To examine seed rain, we placed traps in the canopy and on the ground. We analyzed seed dispersal syndrome (bird, mammal, wind) and plant habit (epiphyte, liana, shrub, small tree, large tree) across all seasons of the year (dry, misty, wet). We found that the community of species collected in canopy traps was significantly different from the community in ground traps. Epiphytes were the most common plant habit found in canopy traps, while large trees were most common in ground traps. Species with bird‐dispersed seeds dominated all traps. Species richness was significantly higher during the dry season in ground traps, but did not vary across seasons in canopy traps. Our results highlight the distinct seed rain found in the canopy and on the ground and underscore the importance of frugivores for dispersing both arboreal and terrestrial plants in tropical ecosystems.     

甘肃莲花山秋季森林小型哺乳类群落结构初步研究

对甘肃省莲花山自然保护区秋季森林小型哺乳类群落的种类组成、多样性和生物量进行了初步研究共捕获7种138只,其中洮州绒鼾、大林姬鼠、中国鼩鼱为群落优势种。区系组成上,东洋界物种偏多。洮州绒鼾、大林姬鼠两种的生物量占绝对优势,水份可能足决定研究区域群落生物量的重要因素。     

Vertebrate‐mediated seed rain and artificial perches contribute to overcome seed dispersal limitation in a Mediterranean old field

Natural regeneration of vegetation is a frequent outcome of land abandonment, although the rate and diversity of such regeneration may be severely restricted by seed dispersal limitation, among other factors. In spite of this, studies aiming to quantify seed rain and test methods to enhance it, such as artificial perches, are still underrepresented in the Mediterranean. In our study, we quantified seed rain density and richness and tested the effects of artificial perches on such rain over a distance gradient on seven Mediterranean island old fields. In each of the seven sites, we positioned three sampling stations, each consisting of 1 seed trap under an artificial perch and 1 as a control on the ground, distributed at 30, 60, and 90 m from natural vegetation remnant. All traps received seeds, suggesting no overall dispersal limitation. Of the 11 seed species found, 10 were fleshy‐fruited and dispersed by vertebrates. Seed traps under perches received significantly higher seed rain of fleshy‐fruited species dispersed by birds, while ground traps received significantly more seeds of the species also dispersed by mammals, especially Rubus ulmifolius. The distance from the seed source was nonsignificant in all cases. Our study demonstrates the key role of vertebrate‐mediated seed dispersal services to overcome dispersal limitation in old fields, as well as the effective contribution of even small artificial perches in contrasting such limitation. The lack of differences over the distance gradient reveal that the upper spatial limit of dispersal limitation was not achieved.     

Community seed rain patterns and a comparison to adult community structure in a West African tropical forest

We examined the seed rain throughout a twelve month period in a lowlandtropical forest in Cameroon, West Africa, 1996–97. Traps (0.5m², n = 216) were erected throughout a 25km² area in 24 randomly placed clusters of nine trapseach. Fruits and seeds that landed in traps were collected every 7–10daysand classified by species and dispersal type. More than 32,000 seeds fromapproximately 200 species fell into the traps, an average of 297 seedsm^–2 yr^–1 Thirty species represent 82%of the total seed rain while an additional 175 species comprise the remaining18%. When we compared the adult community to the seed rain community within thesame plots, we found no apparent correlation between seed rain patterns andadult community structure for this year of study. Furthermore, only 49% of theadult tree community produced and dispersed seed into traps in this year. Morethan 100 species (52%) found in the seed rain represented long-distanceimmigrant seed rain. Seed rain was highly variable at several scales, bothspatially and seasonally, although seeds arrived in traps during eachcollectionperiod. Cluster analyses showed that traps within plots were seldom moresimilarto one another than traps between plots. While 82% of the tree species in thecommunity are thought to be animal dispersed, only 28% of all seeds that fellinto traps had been obviously handled (bitten, chewed, or passed)by animals. Tests for fruit and seed removal by predators or dispersers found5%or less removal rate from traps.     

The role of the seed bank,seed rain and the timing of disturbance in gap regeneration

Abstract. Question: Does the degree and timing of disturbance contribute significantly to the pattern and process of regeneration in plant communities as a consequence of the availability and number of species of propagules present? Location: Acid grassland at 230 m a.s.l., eastern Scotland, UK. Methods : Plots were surface disturbed or had their soil profile inverted at monthly intervals at 12 dates during a year. Seed bank and seed rain were assessed at each treatment time. The effect of disturbance intensity and timing on the regenerating vegetation was assessed. Results: Removing the seed bank significantly slowed regeneration, as it contributed 43 % of developing cover after one year where it was present. At an individual seed level, seed in the seed rain had a much higher likelihood of contributing to the regenerating vegetation than a seed in the seed bank. Some species showed a reliance on the seed bank for regeneration, and hence there was a significant difference in the vegetation that developed between plots with the seed bank intact and those where it was removed. Winter disturbed plots (little seed rain) had slower rates of re‐vegetation than summer disturbed plots. Timing had little effect on species composition, though a significantly higher cover of perennial forb species developed on the winter disturbed plots. Conclusion: Removing the contribution of the seed bank had a greater effect on the composition of regenerating vegetation than the effect of seasonal variation on the seed rain.     

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     

Effect of Bat Exclusion on Patterns of Seed Rain in Tropical Rain Forest in French Guiana

To assess the impact of bats on seed dispersal in a tropical mature forest (Nouragues, French Guiana), we conducted a bat exclusion experiment and tested the hypotheses that an artificial reduction in the abundance of bats would result in: (1) a decrease in seed species diversity, at the community level; and (2) an increase in seed limitation (a failure of seeds to reach all suitable sites for germination) at the species level. Seed rain was sampled in two contiguous forest plots for a total of 120 d, using 49 seed traps (1 m²) arranged in 7 × 7 grids and spaced at 5-m intervals. Using mist nets, bat activity was reduced in one forest plot for a total of 60 nights. Thirty-nine plant species, or species groups, likely to be consumed and dispersed by bats, were collected within a total sample of 50,063 seeds. The overall seed rain was dominated by epiphytic Araceae and Cyclanthaceae (83.3%) and tree species within the genera Cecropia and Ficus (16.0%). Seeds from bat-dispersed shrubs and treelets ( Piper , Solanum , and Vismia ) were relatively rare (0.7%). The bat exclusion resulted in a 30.5 percent reduction in seed species richness and increased seed limitation for most of the species sampled. Seed limitation was caused mainly by a reduced seed rain (seed source limitation) rather than a decrease in seed dispersal uniformity (seed dispersal limitation). Therefore, bat-dispersed plants with low seed production are likely to be particularly affected by a decline in bat abundance, as a result of anthropogenic change.     

Evidence for different bottom-up mechanisms in wood mouse ( Apodemus sylvaticus ) and bank vole ( Myodes glareolus ) population fluctuations in Southern Norway

Animals that feed on forest tree seeds, such as Apodemus mice, increase in number after a mast year. At high latitudes, there is a similar delayed response by Myodes voles to high seed crops of bilberry (Vaccinium myrtillus), but here the mechanism is hypothesised to be increased forage quality, caused by a trade-off between reproduction and defence in the plants. Both Apodemus mice and Myodes voles eat berries, but only the latter feed on bilberry plants. Hence, only Myodes voles are predicted to respond to bilberry peak years. A second prediction is that the effect should last longer than any possible direct impacts of bilberries, because the plants would not be able to rebuild their defence until the succeeding summer. During a 21-year snap-trapping study of small rodents in Southern Norway, the spring population of bank vole (Myodes glareolus) was positively related to a bilberry seed index of the previous year, indicating increased winter survival, whereas the wood mouse (Apodemus sylvaticus) was not affected. Also the succeeding autumn population index of the bank vole was positively related to the bilberry index of the previous year, even when controlling for spring population levels. The wood mouse population responded to mast years of sessile oak (Quercus petraea), whereas seeds of Norway spruce (Picea abies) seemed to have some impact on both species. It is concluded that these rodents are mainly limited from below, but by different mechanisms for the granivorous and the herbivorous species.     

Comparison of three seed trap types in a chalk grassland: toward a standardised protocol

In a chalk grassland in north-western France, vegetation and seed rain were studied along two transects. We compared the efficiency of three types of seed traps (funnel traps, sticky traps, pots exposed in the field) to estimate the annual seed rain and to reveal various processes involved in plant community regeneration. Data were analysed to compare seed density, species richness and composition across seed traps and vegetation. Geostatistical analyses (semivariograms. were used to detect possible autocorrelation and to examine patterns of spatial variation in seed rain and vegetation. The results show that (1) funnel traps are most efficient (56 species, 8079 seeds.m^–2). (2) Each type of seed traps brings different information about the processes involved in seed dispersal and seedling establishment. Sticky traps help to understand import and export of seeds in a community through anemochory. Funnel traps may provide a measure of the auto-regeneration capacity of the vegetation through its local seed production. Pot traps integrate various processes involved between seed dispersal and seedling emergence. (3.) The exposition to environmental conditions generates marked spatial patterns in species richness measured in pots and in vegetation, selecting species able to survive. Pot traps indicate that numerous species producing seeds in standing vegetation are unable to establish in the field through seedling recruitment. Our study emphasizes the need of using different types of seed traps and spatial sampling configurations to assess the regenerative potential of standing vegetation and the various mechanisms involved in seed dispersal. A standardised protocol for seed rain sampling was finally developed.