动物对濒危特有种大别山五针松种子的捕食和散布

大别山五针松(Pinus dabeshanensis)是大别山地区特有树种, 对研究松属(Pinus)植物分类、系统发育关系和区系分布具有重要科研价值。当前大别山五针松野生种群自然更新受到严重限制, 处于极度濒危状态。为探究大别山五针松野生种群更新受限机制, 本研究以大别山五针松及其3种同域分布物种茅栗(Castanea seguinii)、枹栎(Quercus serrata)和华山松(Pinus armandii)为研究对象, 通过开展野外调查和种子释放实验, 探讨了大别山五针松种子产量以及动物对种子的捕食压力和散布限制对大别山五针松自然更新的影响。结果表明: (1)大别山五针松种子产量较低, 在所调查的88株成年母树中, 仅有21株产成熟球果(共计312个), 且种子败育率高达51.89% ± 0.07% (平均值 ± 标准误); (2)针对146个球果的鸟类啄食情况调查表明, 被鸟类啄食的球果数量为90个, 显著高于未被鸟啄食的球果数量(56个), 平均啄食强度为8.94% ± 0.55%; (3)种子掉落地表后, 小型啮齿动物和地栖鸟类(主要为松鸦 Garrulus glandarius)为主要动物拜访者, 其拜访频率在不同物种之间差异显著; 其中鸟类对大别山五针松种子的拜访次数(n = 77)高于啮齿动物(n = 46); (4)种子释放实验结果表明, 茅栗种子被收获速率最快, 显著高于枹栎和大别山五针松, 华山松种子的被收获速率最慢; (5)在释放的2,000粒种子中, 共计157粒被成功散布, 其中华山松和大别山五针松分别为96粒和57粒, 显著多于茅栗(3粒)和枹栎(1粒); (6)茅栗的散布距离最远(13.9 ± 4.0 m), 其次是大别山五针松(7.3 ± 0.8 m)、华山松(3.8 ± 0.4 m)和枹栎(1.5 m, 仅有1粒被成功散布)。综上所述, 啮齿动物和鸟类均为大别山五针松种子的潜在散布者, 与同域分布的其他植物物种相比, 动物并未表现出更高的捕食强度和更低的散布效率, 表明种子的被捕食压力和散布限制并非影响大别山五针松自然更新的主要因素。此外, 本研究发现, 大别山五针松种子产量较低且种子败育率较高, 可能是导致其自然更新受阻的重要原因之一。     

濒危植物大别山五针松母树林花粉传播规律

大别山五针松是典型的风媒传粉植物,花粉流是种群基因流的重要形式。用重力玻片法研究大别山五针松母树林的花粉飞散特征,分析了时间和空间对花粉飞散的影响,结合林分密度和气象因子探讨花粉飞散的特点。结果表明:大别山五针松从5月中旬开始传粉,散粉期为14d,盛粉期为3d,种植密度低的下坡花粉密度比密度大的上坡的要高。日散粉最大值出现在10:00～14:00,植株中上部花粉密度较高,距花粉源50m处花粉密度最高。建议对种植密度大的区域移栽以促进花芽生成,以保证结实率与提高种子品质。     

大别山五针松群落物种多样性及区系分析

设置22个20m×20m的样地,对大别山五针松群落的物种多样性和区系成分进行了研究。结果显示,8800m²的样地内共有维管植物71科152属209种。其中,蕨类植物4科5属6种,裸子植物3科3属4种,被子植物64科144属199种。蔷薇科、樟科、菊科、杜鹃花科、豆科和禾本科等为优势科,所含物种较多。分析结果表明,大别山五针松群落种子植物区系起源古老,地理成分复杂,67个科中,世界分布、热带和温带分布的科分别有21、31和15个,显示出由热带向温带过渡的特性。147个属中,热带成分共43属,占总属数（不包括15个世界广布属）的32.58%;温带成分共有89属,占总属数的67.42%,并以北温带为主。群落垂直结构分为乔木层、灌木层和草本层,其中,Margalef指数、Simpson和Shannon-Wiener指数均以灌木层最大,其次为乔木层,草本层最低。灌木层与草本层的Pielou指数相近,且均大于乔木层。     

大别山五针松种内和种间竞争强度

通过对安徽省岳西县大别山五针松群落内的53株对象木及2079株竞争木的调查,运用Hegyi单木竞争模型分析了大别山五针松的种内和种间竞争强度。结果表明,大别山五针松的种内和种间竞争强度分别为17.11%和82.89%,说明竞争主要来自种间。大别山五针松的伴生种较多,种内与主要伴生种间的竞争关系为短柄枹大别山五针松种内黄山松满山红茅栗金缕梅紫茎四照花灯台树鹅耳枥。竞争强度随对象木胸径的增大而减小,当对象木的胸径小于25cm时,所受到的竞争强度较大;当胸径在25cm以上时,竞争强度变化很小,二者符合幂函数关系(CI=AD-B),所得的预测模型能很好的预测大别山五针松种内和种间竞争强度。     

不同贮藏温度下大别山五针松花粉活力的变化

大别山五针松( Pinus dabeshanensis C. Y. Cheng et Y. W. Law)为松科( Pinaceae)松属( Pinus Linn.)植物,自然种群数量极少,目前仅发现在安徽省岳西县大王沟海拔900~1300 m阴坡和半阴坡有相对集中的分布,种群规模计200余株,且多为成年个体,林下幼苗极少,自然更新困难,为中国特有珍稀树种之一[1]。大别山五针松常在每年3月份至4月份形成花芽,5月中下旬花粉成熟并散发,花粉具气囊,此时雌球花张开接受传粉,球果翌年9月成熟[2]。据作者近年的调查,大别山五针松种子败育率较高,且种子质量较低,这也是该种类濒危的重要原因之一。     

华南五针松濒危机制生态学研究

为了揭示珍稀濒危特有种华南五针松天然种群的生存状况,在全面调查广东南岭国家级自然保护区华南五针松分布的基础上,结合文献收集法,利用群落内不同乔木的胸径、树高、冠幅等指标,计算不同海拔梯度内华南五针松种群的平均生存压力,分析不同海拔梯度内华南五针松种群的空间格局。结果表明：1)、海拔高度和温度影响群落的空间格局,沿994m至1600m的海拔梯度上华南五针松种群空间格局以聚集为主,且随海拔的升高,种群聚集强度增加,当达到1600m时,聚集强度降低,种内和种间竞争减缓,生存压力变小;2)、华南五针松种群平均生存压力指数总体沿海拔梯度上升呈递减趋势(R²=0.31,P<0.05),中低海拔华南五针松种群生存压力较大,高海拔聚集强度降低,生存压力减小,华南五针松有向高海拔迁移的可能,当达到1710m以上时,最终会因分布区逐渐缩小、生存环境恶劣和不适应等因素造成最终灭绝;3)、群落种间结构的复杂性造成种间和种内竞争激烈,同一海拔梯度上华南五针松种群平均生存压力指数不同;4)、针对华南五针松人工林,种群平均生存压力指数为50,受到来自竞争树种的威胁大,需加以严格保护。华南...     

濒危植物大别山五针松枝叶NPK化学计量特征季节动态

为了解我国特有珍稀濒危植物大别山五针松(Pinus dabeshanensis)枝和叶的养分状况及其季节变化特征,连续12个月对其开展野外取样和室内分析,探讨了枝叶N、P、K含量及其化学计量比的动态变化及其在器官间的差异性。结果表明,器官和月份对大别山五针松化学计量特征有显著影响,其中器官的影响最大。枝和叶化学计量特征的季节变化不规律,N∶K变异系数最大(枝叶分别为26.75%和28.00%),其余均属弱变异(变异系数<25%)。叶N、P、K平均含量(10.40、1.43及5.15 mg·g-1)显著高于枝(6.56、1.26及4.80 mg·g-1),叶N∶P(7.27)也显著高于枝(5.18),但枝和叶N∶P均远低于14,呈严重N限制。枝和叶N∶P、N∶K及P∶K分别受制于N、K和K(即相关系数最大)。枝和叶N、P和K之间(枝N-K除外)具有显著的相关性和异速生长关系,其中叶N分配速率高于枝而P分配速率低于枝。降水和温度对枝叶化学计量特征有不同影响。降水量具有明显的时间尺度效应,短时间尺度降水多影响叶而长时间尺度多影响枝。在各时间尺度下,温度均与叶P含量呈显著负相关而与枝K含量呈显著正相关。综合来看,大别山五针松枝、叶间化学计量特征差异显著,且具有明显的季节变异,在一定程度上受降水和温度的影响。     

濒危植物大别山五针松根际细菌群落特征与功能分析

植物根际微生物群落对植物健康生长有重要影响, 每种植物根际都有其特定的微生物群落。大别山五针松(Pinus dabeshanensis)被国际自然保护联盟列为濒危物种, 具有重要研究价值。该研究采用16S rRNA高通量测序技术与生物信息学方法, 对濒危植物大别山五针松根际细菌群落特征与功能进行分析。结果表明, 大别山五针松根际微生物的主要种类为变形菌门、放线菌门、酸杆菌门和疣微菌门。网络分析表明, 大别山五针松根际细菌类群存在显著相关性, 其中Bryobacter属、Bradyrhizobium属和未定义的TK10属是互作网络中的重要节点。PICRUSt1功能预测表明其微生物组功能主要为氨基酸运输和代谢、细胞壁/膜/膜生物发生以及能量产生和转换。FAPROTAX功能预测表明, 大别山五针松根际富含的优势菌群具有丰富的化学异养、纤维素水解、需氧化学异养和固氮功能, 其对植物生长发育具有重要作用。研究结果可为培育健康的大别山五针松根际微生物菌群及微生物资源的开发利用提供重要依据。     

海南五针松人工林分生物量的研究

 本文是对海拔930m的17年生海南五针松(Pinus fanzeliana)人工林分生物量和生产力进行了测定和研究。按平均标准木法和样方收获法分别调查了乔木层,灌木层,草本地被物层和枯枝落叶层。据调查数,建立了估测乔木层单株林木各器官干重的回归方程。方程的相关系数和估测精度都较高,具有参考价值．分析结果表明：林分总生物量平均为161.152t／ha,生产力为10630.69kg／(ha·a),其中：乔木层生物量为149.351t／ha,生产力为11095kg／(ha·a),叶面积为199248.734m2／ha,叶面积指数为19.9149m2／m2。     

大别山五针松根际微生物和内生菌群落特征及功能多样性

为探明大别山五针松根际微生物和内生菌群落特征及功能多样性,该文以大别山五针松根际土壤和根部组织为研究对象,利用高通量测序技术分析根际微生物和根部内生菌群落特征,并利用PICRUSt和FUNGuild软件分别对细菌群落和真菌群落进行功能预测。结果表明：(1)根际微生物总操作分类单元(OTUs)数目和α-多样性指数均明显大于根部内生菌。(2)根际微生物主要由厚壁菌门(如李斯特氏菌属)、变形菌门(如醋杆菌属)、子囊菌门(如镰刀菌属和毛壳属)等菌群构成,而根部内生菌则以厚壁菌门(如乳杆菌属和芽孢菌属)、子囊菌门(如枝孢菌属)、担子菌门(如须腹菌属和针菌属)菌群为主。(3)功能预测结果显示,根际细菌群落在细胞运动性、环境适应性、氨基酸代谢等功能方面较为突出,而根部内生细菌功能主要体现在酶家族、消化系统、能量代谢等方面;根际真菌群落和根部内生真菌均含有共生营养型、腐生营养型、病理营养型,以及多种交叉营养型的真菌类群,并且外生菌根更多富集在根部组织中。该研究认为,大别山五针松根际微生物与根部内生菌在菌群丰富度、群落结构组成及功能多样性上均存在差异。该研究结果为认识大别山五针松根际微生物和内生菌的结构与功能提供了依据,也为后期开发促进大别山五针松生长、防治其病害的菌剂提供了一定的理论基础。     

沙地樟子松天然林南缘分布区林木竞争、空间格局及其更新特征

以呼伦贝尔沙地樟子松地理分布南缘天然林为研究对象,采用Hegyi竞争指数与点格局等分析方法,研究了沙地樟子松天然林的种群结构、种内竞争、空间格局及幼树更新等特征。结果表明:1)所调查区域天然沙地樟子松纯林处于中幼龄阶段,属增长型种群;2)其竞争指数与对象木胸径服从幂函数关系CI=242.24D~(-1.12)(R~2=0.91);3)幼树在小尺度上呈聚集分布,中树与大树在中大尺度上呈随机分布;幼树与中树在小尺度上呈正相关性,中树与大树在小尺度呈负相关性;4)竞争指数与更新幼树和存活更新幼树的密度均呈显著正相关性。在林分管理中需要充分考虑林木竞争、空间格局以及种群更新的关系,本研究可为沙地樟子松天然林的经营管理与保护提供重要的科学依据。     

Removal and predation of Quercus liaotungensis acorns by animals

Two types of acorns (fresh, current-year acorns and old, previous-year acorns) of Quercus liaotungensis were used under two different situations (night and day) to examine the removal and predation by animals in the field. The acorns disappeared very fast. During the day, all of the 280 this-year acorns (TA) and all of the 140 last-year acorns (LA) were removed by animals within 6 h and 5 h, respectively, after acorns were put in place. At night, all of the 280 TA acorns were removed by animals within 10 h after acorns were distributed, and 71 out of 140 LA acorns were removed within 10 h. Animals consumed a small proportion of acorns in situ (11.8%). The number of TA acorns consumed in situ at night was higher than that during the day. During the day, the number of LA acorns consumed in situ was significantly higher than TA acorns. This result suggests that the most important harvesters of Q. liaotungensis during the day were visually orientated diurnal animals, and the most important harvesters at night were olfactorily orientated nocturnal animals. Furthermore, the latter are more efficient than the former at finding and harvesting acorns, because they spend less energy on harvesting the same number of sound acorns.     

Distribution patterns and predation risk of the coexisting cladocerans Bythotrephes longimanus and Leptodora kindtii in a large lake – Lake Constance

The distributions of the coexisting, planktonic, predatory cladocerans Bythotrephes longimanus and Leptodora kindtii were studied at four different stations (Langenargen-Arbon, Fischbach-Uttwil, Bregenzer Bucht and Zeller See) of a great lake, Lake Constance. The stations Langenargen-Arbon and Fischbach-Uttwil are deep (>200 m) with a high density of the coregonid fish Coregonus lavaretus, the stations Bregenzer Bucht and Zeller See are shallow (<60 m) with lower densities of coregonid fish. B. longimanus was present in the pelagic zone from mid May to November at all stations. L. kindtii generally appeared slightly later in the year than B. longimanus. Peak abundances of B. longimanus with more than 5000 ind. m^–2 (Langenargen-Arbon) appeared in late spring. During summer, when predation pressure by fish is high, abundance of B. longimanus decreased gradually. In contrast, L. kindtii displayed maximum abundances with more than 18 000 ind. m^–2 (Zeller See) in summer. During the summer months, B. longimanus lived in greater depths than L. kindtii. Differences of vertical distribution between both species were most pronounced at the deep stations (Langenargen-Arbon, Fischbach-Uttwil). Analysis of stomachs of the planktivorous fish Coregonus lavaretus showed that B. longimanus was preferred by C. lavaretus over all other prey; Ivlev's selectivity index was 0.97–0.99. Due to this high positive selection for B. longimanus by coregonids, it is surprising that the cladoceran could maintain its existence since the first recordings in 1877. Spatial refuge or indigestible resting eggs may be the underlying mechanism for this phenomenon.     

Post-dispersal predation and scatterhoarding of Dipteryx panamensis (Papilionaceae) seeds by rodents in Panama

In tropical rain forests of Central America, the canopy tree Dipteryx panamensis (Papilionaceae) fruits when overall fruit biomass is low for mammals. Flying and arboreal consumers feed on D. panamensis and drop seeds under the parent or disperse them farther away. Seeds on the ground attract many vertebrate seed-eaters, some of them potential secondary seed dispersers. The fate of seeds artificially distributed to simulate bat dispersal was studied in relation to fruitfall periodicity and the visiting frequency of diurnal rodents at Barro Colorado Island (BCI), Panama. The frequency of visits by agoutis is very high at the beginning of fruitfall, but in the area close (<50 m) to fruiting trees (Dipteryx-rich area) it declines throughout fruiting, whereas it remains unchanged farther (>50 m) away (Dipteryx-poor and Gustavia-rich area). Squirrels were usually observed in the Dipteryx-rich area. Along with intense post-dispersal seed predation by rodents in the Dipteryx-rich area, a significant proportion of seeds were cached by rodents in the Dipteryx-poor area. Post-dispersal seed predation rate was inversely related to hoarding rate. A significantly greater proportion of seeds was cached in March, especially more than 100 m from the nearest fruiting tree. This correlates with the mid-fruiting period, i.e. during the height of D. panamensis fruiting, when rodents seem to be temporarily satiated with the food supply at parent trees. Hoarding remained high toward April, i.e. late in the fruiting season of D. panamensis. Low survival of scatterhoarded seeds suggests that the alternative food supply over the animal's home-ranges in May–June 1990 was too low to promote survival of cached seeds. Seedlings are assumed to establish in the less-used area of the rodents' home-range when overall food supply is sufficient to satiate post-dispersal predators.     

贵州闽楠天然种群特征、空间分布格局及空间关联分析

为更好地保护闽楠天然种群,探究闽楠天然种群特征、空间分布格局及其空间关联性,对针对性地提出保护措施具有重要意义。以贵州台江县登鲁村闽楠天然种群为研究对象,通过野外设置60 m×60 m固定样地,采用种群径级结构代替年龄结构、点格局分析方法分析闽楠种群年龄结构、不同生长阶段空间分布格局及其关联性。结果表明：（1）闽楠种群年龄结构呈倒\"J\"型分布,幼龄个体数量多,随着年龄增加,能够成功进入后期的个体数量急剧下降,死亡率高。存活曲线趋于Deevey-Ⅱ型,属于稳定型种群。种群在第5龄级（7.5 cm≤DBH<12.5 cm）的生命期望（e_x）最高。（2）闽楠种群分布格局由随机分布转向随机分布。在幼苗、幼树、中树阶段空间分布格局趋于集群分布,大树阶段趋于集群分布。（3）不同生长阶段之间空间关联性表现有所差异。小尺度上,大树与幼树呈负关联,大尺度上,两者呈正关联;小尺度上,幼树与幼苗、大树与幼树都呈正关联,大树和中树无关联,在大尺度上,大树和中树、幼树与幼苗、中树与幼苗以及中树和幼树都呈负关联且随着空间尺度的增加负关联性逐渐增强。总体而言,该闽楠天然种群较稳定,但对环境干扰敏感,幼龄个体因呈聚集分布受密度制约而竞争剧烈,成年个体则因对环境的竞争而呈随机分布。为维持种群的长期稳定,需要分阶段适时进行人工调控。     

辽河源自然保护区油松群落特征及优势种群结构

通过实地踏查,选取辽河源自然保护区内成片的不同年龄的油松天然次生林群落,采用样方法进行群落学特征信息调查,分析研究区的群落区系特征、外貌特征和优势种群结构特征,为油松天然林的保护和抚育管理提供理论依据。结果表明：（1）辽河源自然保护区油松天然次生林群落中共有种子植物41科90属144种,植物种类丰富,具有明显的温带针叶林特征,以地面芽植物为主（60.27%）,中叶植物占优势（82.19%）;区系组成与温带的成分关系最为密切。（2）优势种油松在研究区构成成片的不同林龄的纯林,幼龄林的群落中小径级（Ⅰ~Ⅲ）个体所占比例较高（75%）,随着年龄增加,大径级个体所占比例逐渐增加,成熟林径级呈正态分布,各龄组高度级和冠幅的变化趋势与径级相似。（3）4个龄组幼苗储备都很丰富,均占更新层的58%以上,成熟林中幼苗所占比例达90%,但幼树比例较少,群落的更新状况不佳,但潜在更新能力较强。     

云南松三种同域共存切梢小蠹梢转干期的空间分布格局

分布在我国西南地区的横坑切梢小蠹,云南切梢小蠹和短毛切梢小蠹同域危害寄主云南松,给林业生产带来巨大损失。为探讨同域切梢小蠹种群在共存下对其空间分布格局的影响,采用传统聚集指标法和地统计学方法研究了三者在梢转干期不同受害云南松纯林树冠中的空间分布型。结果表明重度受害样地中云南切梢小蠹种群密度显著高于横坑切梢小蠹,在轻度受害样地则相反;传统聚集指标法结果显示同域共存的3种切梢小蠹种群在不同受害程度云南松中均为聚集分布,横坑切梢小蠹和云南切梢小蠹聚集是由环境因素和昆虫本身的聚集习性引起;地统计学结果表明除重度受害样地中短毛切梢小蠹呈随机分布外,其余切梢小蠹在不同种群密度下均呈聚集分布;除重度受害样地横坑切梢小蠹外,其他小蠹的空间依赖范围为4.01—7.45 m。横坑切梢小蠹和云南切梢小蠹在不同受害林分中拟合的半变异函数模型在球形模型和高斯模型之间转换。同域共存关系不影响不同种群密度下的切梢小蠹种群空间分布类型,但影响其半变异函数模型和理论参数。     

Some factors affecting size distribution and density of grass shrimp (Palaemonetes pugio) populations in two New Jersey estuaries

Mature Palaemonetes pugio, from a polluted estuary, Piles Creek (PC) are larger than those in a more pristine estuary in Tuckerton (TK). Possible causes for the differences in size-structure could be differences in environmental factors at the two creeks, differential competition at the two sites, inherent factors causing a greater growth rate in the PC population, differences in reproductive timing, or differential predation at the two sites. Lab microcosm studies were used to examine the possibility of inherent population differences or environmental conditions (including differences in salinity) causing faster growth in PC. There was no evidence that PC shrimp grew faster than TK shrimp, nor that PC conditions fostered greater growth compared to TK. Salinity adjustments in PC and TK tanks also had no effect on growth. Therefore, it appears that genetic and environmental factors did not play a significant role in greater shrimp growth in PC. In the field, data on relative abundances of Fundulus heteroclitus and P. pugio, and size-frequency distributions of P. pugio were collected from the two estuaries. Gravid females and recruits of young shrimp physically appeared at approximately the same time within both systems, eliminating earlier reproduction as a cause of the size discrepancy. There were three times as many shrimp in PC than in TK (eliminating the possibility of increased population density and competition at TK as a cause) and three times as many F. heteroclitus present in TK than in PC. Since it has already been established that the Fundulus at PC are smaller than at TK and that they are poor predators, differences in Fundulus predation would appear to be an important factor in determining the number and size-frequency of the grass shrimp.