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1.
Taking Elaeagnus mollis Diels and seven dominant woody species in its community from Yicheng County of Shanxi Province as research objects, leaf traits including specific leaf area (SLA), nitrogen content in leaf per unit area ( Narea ) , leaf dry matter content ( LDMC ) and photosynthetic nitrogen use efficiency ( PNUE ) were compared, and correlations of SLA value with LDMC and PNUE values were analyzed. The results show that there are different degree variations in four indexes of leaf traits of E. mollis, Vitex negundo var. heterophylla ( Franch.) Rehd., Broussonetia papyrifera ( Linn.) L' Hér. ex Vent., Lespedeza bicolor Turcz., Caragana microphylla Lam., Rosa xanthina Lindl., Amygdalus davidiana ( Carrière) de Vos ex Henry and Periploca sepium Bunge, in which, SLA value with the largest coefficient of variation ( 404%) , and LDMC value with the lowest coefficient of variation ( 103%) . Compared with other tested species, SLA and PNUE values of E. mollis are the lowest ( 103 cm-2 · g-1 and 108 μmol · mol-1 · s-1 , respectively) , while its Narea value is the highest ( 0243 g · m-2 ) , and its LDMC value is also relatively high ( 0380 g·g-1 ) . SLA value of eight tested species show an extremely significant positive correlation ( P<001) with PNUE value, and a significant negative correlation ( P<005 ) with LDMC value, correlation coefficient are 0923 and -0718, respectively, indicating that SLA value is an important parameter of leaf photosynthetic capacity and resource utilization ability. It is suggested that compared with other dominant woody species, E. mollis is more sensitive to environmental change, and has a poor environmental adaptability. 相似文献
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甘肃兴隆山自然保护区森林演替对鸟类群落结构的影响 总被引：12，自引：0，他引：12
运用固定面积法调查了青林三个主要演替阶段森林(阔叶林、混交林和针叶林)的鸟类群落结构。结果表明,混交林中鸟类物种数、鸟类物种多样性和种团多样性最高,阔叶林最低。方差分析和聚类分析均表明,三种演替阶段森林的鸟类群落组成差异显著。所记录到的35种鸟类中有11种差异显著。其中,山雀科和科在阔叶林中占优势,而柳莺亚科在混交林和针叶林中占优势。食性种团中,阔叶林以食虫鸟和食果食虫鸟为主;混交林和针叶林均以食虫鸟、食果食虫鸟、食谷鸟和食果鸟为主。鉴于阔叶林和混交林有向顶级群落(针叶林)演替的趋势,建议采取人为干扰来维持三种演替阶段森林的面积,以便从景观水平上保护鸟类物种多样性。 相似文献
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外来植物入侵严重威胁着当地生物多样性和生态系统功能,引发巨大经济损失,已成为日益严重的全球性问题。光是热带和亚热带森林生态系统植物生长最重要的限制性资源之一,对光的捕获和利用直接影响植物在自然生态系统中的生存和适合度。本研究以华南地区危害严重的入侵植物薇甘菊(Mikania micrantha)和飞机草(Chromolaena odorata)为研究对象,对比二者生长、生物量分配及叶片特征对光照强度变化的响应,从而验证假设:外来植物入侵力受有效光辐射的限制,光照是影响不同演替阶段林型具有不同可入侵性的重要原因之一。研究结果表明,3%—60%全光照下两种外来植物均可存活,并显示较灵活的生物量分配策略,可见其对光照具有广适性,为其广泛分布提供生态学基础。低光严重抑制了两种外来植物的生物量积累,这可能是导致演替后期季风林入侵现象少的主要原因之一。对比两种植物叶片特征对光照强度变化的响应,高光下薇甘菊SLA降低,LAR、LARMR减小,叶片变小变厚,有利于植株保持强光下的水分平衡;低光下薇甘菊增加SLA和LAR,叶片变薄变大,增大对光的截获面积,以实现对光强减弱的适应。相比薇甘菊,3种光照处理对飞机草的SLA、LAR、LARMR无显著影响。以上结果提示:(1)光照影响所在群落对外来植物入侵的抵抗力;(2)攀援植物薇甘菊较丛生型草本飞机草对变化的光环境在叶片水平上具有更高的形态可塑性,有效寻觅光资源。 相似文献
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温度对黄瓜幼苗光合生理弱光耐受性的影响 总被引：3，自引：0，他引：3
以不耐弱光的津研2号和较耐弱光的戴多星黄瓜(Cucumis sativus L.)为试材,在人工气候室内研究适温25 ℃/18 ℃（昼/夜）、亚适温15 ℃/9 ℃和低温9 ℃/7 ℃对弱光(75～85 μmol·m-2·s-1)耐受性的影响.结果表明：弱光下黄瓜叶片的SPAD、净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、水分利用效率（WUE）、实际光化学效率（ΦPSⅡ）、光化学猝灭（qP）等指标下降,下降程度随温度的降低而加剧,而超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性上升.逆境解除后的恢复过程中,光合和荧光参数逐渐恢复,荧光参数恢复速度快于气体交换参数.弱光下温度越低对黄瓜幼苗叶片光合机构造成的伤害越重,低温降低了叶片对弱光的耐受性.在低温、弱光处理过程中,津研2号Pn、ΦPSⅡ、qP等下降程度较戴多星明显,而在随后的恢复过程中其回升速度较戴多星迟缓,表明弱光下戴多星对低温的耐受性强于津研2号. 相似文献
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该研究运用方差比率法、χ~2检验、Pearson相关检验和Spearman轶相关检验,对广西雅长兰科植物国家级自然保护区南盘江流域的细叶云南松(Pinus yunnanensis Franch.var.tenuifolia Cheng et Law)次生林14个大树树种(DBH≥10cm)、15个小树树种(5cm≤DBH10cm)和19个幼树树种(1cm≤DBH5cm)进行定量分析,以揭示南盘江流域细叶云南松次生林群落中木本种群的关联性及其更新演替规律,为桂西北细叶云南松林管理保护、干热河谷地区植被恢复和生态重建提供参考依据。结果表明:(1)研究区内细叶云南松林大树和小树的总体关联性表现为不显著负关联,幼树及群落总体表现为不显著正关联;χ~2检验显示,大树和小树负关联种对占多数(分别为48.35%和46.67%),幼树的正关联或负关联种对占比基本持平(分别为40.35%和39.18%),群落整体无关联种对占比较大(41.13%)。(2)Pearson相关系数和Spearman秩相关系数检验显示,细叶云南松林的大树、小树、幼树和群落总体均表现为负关联种对较多,正关联次之。(3)群落大树和小树物种在资源竞争上较激烈,结构不稳定;群落幼树物种适应了林下荫蔽环境,对光照要求较低,种间关系已具有较低的稳定性,个别物种表现出独立性。研究认为,南盘江流域细叶云南松次生林群落物种间存在一定的关联性,但未能形成稳定的配置关系,群落结构尚不稳定,仍处于演替早期阶段。 相似文献
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外来植物入侵已成为严重的环境和社会问题,了解外来植物的入侵机制是有效控制其入侵的前提。生物阻抗假说认为,入侵地本地植物群落中的许多生物因子及生物过程能够抵御外来植物入侵。但关于群落抵抗外来种入侵的主要机制,目前还没有确定的结论。本文综述了群落中物种功能特征的多样性以及与外来种功能特征的相似度、植物与动物、植物与植物以及植物与土壤微生物间的相互作用等因素对外来植物入侵的影响,以及以前研究存在的不足。未来研究应该注重不同条件下植物与植物间的相互作用;不同竞争强度下,植物与食草动物的相互作用;植物、动物及土壤微生物三者之间的相互作用对外来植物入侵的影响。这些研究不仅能够丰富和完善入侵生态学理论,而且对于预测外来植物未来的扩散范围,合理有效地管理生态系统,防止外来植物入侵,保护本地生物多样性具有重要的实际意义。 相似文献
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采用 2× 2列联表 ,通过方差分析、χ2检验、Ochiai指数对黑石顶森林次生演替过程中各阶段群落优势种的种间联结性进行了定量分析。研究结果表明 :群落的总体种间关联性在演替恢复初期表现为无相关性 ,针阔叶混交林阶段为总体的正关联 ,阳生性常绿阔叶林阶段呈总体负关联 ,中生性常绿阔叶林阶段总体呈显著正关联。在演替初期主要种对间尚未形成一定的种间关系 ,演替至混交林和阳生性常绿阔叶林阶段 ,种间关系开始形成 ,但大多表现为直接的竞争关系 ,中生性常绿阔叶林阶段形成了复杂多样的种间关系 ,表现为同层树种间的种间结合或竞争和不同层种间的结合关系 相似文献
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【目的】发现 支配权衡(discovery-dominance trade-off)在物种间的竞争起着重要作用。本研究旨在了解不同强度的红火蚁Solenopsis invicta入侵对本地蚂蚁群落物种的发现 支配权衡的影响,从而探讨红火蚁与本地蚂蚁的竞争机制。【方法】于2017年10-11月,在云南省楚雄州牟定县的一滇橄榄种植基地利用诱饵法和陷阱法结合的方式引诱和收集蚂蚁,观察并记录常见蚂蚁种类的发现能力、招募能力、支配能力、最早发现诱饵的时间段及个体数。【结果】红火蚁的入侵显著影响了本地蚂蚁群落物种的发现-支配权衡。强入侵区(5.6个活动蚁巢/100 m2)蚂蚁群落中物种的相对发现能力和相对支配能力不存在相关性;弱入侵区(0.14个活动蚁巢/100 m2)蚂蚁群落中两者存在较弱的负相关性,但不显著;对照区(无蚁巢)中两者存在显著负相关性(强入侵区：r=-0.01, P=0.97;弱入侵区：r=-0.60, P=0.21;对照区：r=-0.81, P=0.04)。强入侵区的红火蚁种群普遍在5 min之内就能发现诱饵,而弱入侵区的种群需要10~60 min才能发现诱饵(χ2(5)=33.37, P<0.001);强入侵区的红火蚁种群在发现诱饵频率和支配行为频率上均显著高于弱入侵区(发现诱饵频率: χ2(1)=17.27, P<0.001; 支配行为频率: χ2(1)=6.25, P=0.03),而招募频率在两种入侵区间无显著差异(χ2(1)=1.75, P=0.55)。【结论】红火蚁入侵打破了本地蚂蚁群落物种的发现-支配权衡,而且随着红火蚁种群规模的增大,从能够影响到完全打破这种发现 支配权衡。研究结果可为了解红火蚁入侵机制提供证据。 相似文献
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紫茎泽兰叶片化感作用对10种草本植物种子萌发和幼苗生长的影响 总被引：118，自引：3，他引：118
化感作用在生物入侵过程中具有重要的意义,紫茎泽兰具有化感物质,它能抑制豌豆等一些对化感物质敏感的植物种子萌发,但它对入侵早期直接与之竞争的植物的影响以及化感作用与其入侵性的关系还知之甚少。以紫茎泽兰入侵早期直接与之竞争的草本植物和为替代控制紫茎泽兰引进的牧草为材料,利用培养皿滤纸法研究紫茎泽兰叶片提取液对种子萌发和幼苗生长的影响,探讨化感作用与其入侵性的关系,并为其替代控制提供依据。紫茎泽兰叶片提取液对10种受体植物种子萌发和幼苗生长均有化感作用,不同浓度的提取液对植物的化感作用强度不同,低浓度时较弱,高浓度时较强。高浓度的提取液能降低种子发芽率、发芽速率、胚轴和胚根长度,增加幼苗丙二醛含量,其中发芽速率更敏感,可能是衡量化感作用的最敏感指标。不同植物对紫茎泽兰化感作用的敏感程度不同,无芒虎尾草、白三叶、细叶苦荬和莎草砖子苗对紫茎泽兰化感作用较敏感,紫花苜蓿最不敏感。 相似文献
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Hasan Yusuf Anna C. Treydte Sebsebe Demissew Zerihun Woldu 《African Journal of Ecology》2011,49(4):397-409
Ecological survey was executed to assess woody species encroachment into the grassland plain of Nechisar National Park (NNP). Forty‐one woody species were recorded. Dichrostachys cinerea Wight & Arn., Acacia mellifera (Vahl) Benth., Acacia nilotica (L) Willd., Acacia senegal (L.) Willd., Acacia seyal Del. and Acacia tortilis (Forssk.) Hayne were among the major encroaching woody species. The majority of the woody species were found to be highly aggregated in their pattern of distribution, while only few species showed some degree of randomness. The mean woody species density was ca. 1995 woody plants ha?1. Mean cover of woody, grass, unpalatable forbs and total herbaceous species were 31%, 58%, 68% and 121%, respectively. The woody species density and cover, unpalatable forbs and bare land cover were significantly higher in the highly grazed and fire‐suppressed part of the grassland plain. Pearson correlation coefficient matrix indicated that woody species cover and density were negatively correlated with total herbaceous and grass cover. The high woody, unpalatable forbs and bare land cover indicated the progressively increasing perennial grass species diversity deterioration in the grass plain of the Park. Decline in the grassland condition, unless reversed, will jeopardize the biological diversity as well as the aesthetic value of the NNP. 相似文献
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植被恢复树种在不同实验光环境下叶片气体交换的生态适应特点 总被引：17，自引：0，他引：17
比较研究了华南丘陵地区植被恢复8种乔木树种在不同光条件下的光饱和点、日平均净光合速率、叶温、气孔导度日平均值、内在水分利用效率和光合辐射利用效率等生理生态特征。结果表明,火力楠和藜蒴具有演替后期种的特征,在荫蔽条件下生存和生长良好,它们不宜用作构建先锋群落的树种。大叶相思、马占相思和樟树是典型的阳生性树种,具有鲜明的演替后期种的特征;红椎和海南红豆显示除叶温以外的阳生性的特征。这些种类可被选作构建先锋群落的组成成分。桂西红荷则只能作为演替的过渡种类,它兼具有演替前期种和演替后期种的特征,尤其适用于对先锋群落进行林分改造。 相似文献
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Eugen Grzen Karina Borisova Annamria Fenesi Eszter Ruprecht Tobias W. Donath 《应用植被学》2019,22(3):409-422
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- Invasion biology often focuses on the life‐history traits and the physiological tolerance of introduced species, and on assessing the suitability of receiving habitats. Few studies have examined how trait variation in recipient communities affects the responses of native fauna to pressures from invasive species.
- This study examines how previously identified life‐history differences in a species‐complex of native New Zealand galaxiid fish influence their spatial interactions with invasive salmonids (mainly Salmo trutta, but also Oncorhynchus mykiss, O. tshawytscha and Salvelinus fontinalis).
- A combination of a long‐term, broad‐scale, presence–absence dataset and a more intensive electrofishing survey was used to examine the extent to which galaxiid species distributions overlap with those of salmonids, and to assess demographic effects associated with salmonid presence. A generalised linear modelling approach was used to test the effect of life history on galaxiid–salmonid interactions while taking into account the possible confounding effects of habitat differences between species distributions.
- Galaxiid species with ‘fast’ life‐history traits (e.g. high fecundity, small eggs) regularly co‐occurred with salmonids over extensive areas, sometimes over long periods, occasionally where salmonid densities were high. In contrast, galaxiid species with ‘slow’ life‐history traits (e.g. low fecundity, large eggs) were almost never found co‐occurring with salmonids, and evidence suggested they were most often excluded even where salmonid densities were low. The model outputs indicated that, although habitat played an important role, galaxiid life histories were a dominant factor determining whether species co‐occurred with or were excluded by salmonids.
- The strong influence of interspecific life‐history variation on how these closely related galaxiid species interact with salmonids demonstrates the importance of detailed life‐history information in predicting how native biota are likely to respond to pressures from invasive species.
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Paulina Andrea Bahamonde Gustavo Chiang Gabriela Mancilla Tamara Contador Caudio Quezada-Romegialli Kelly Roland Munkittrick Chris Harrod 《Journal of fish biology》2024,104(1):139-154
Salmonids were first introduced into the Chilean fresh waters in the 1880s, and c. 140 years later, they are ubiquitous across Chilean rivers, especially in the southern pristine fresh waters. This study examined the brown trout (Salmo trutta) and native taxa ecology in two adjacent but contrasting rivers of Chilean Patagonia. During spring 2016 and spring–fall 2017 we examined the variation in benthic macroinvertebrate and fish community composition and characterized fish size structure, stomach contents, and stable isotopes (δ13C and δ15N) to understand population structure, fish diet, and trophic interactions between S. trutta and native taxa. The native Galaxias maculatus (puye) dominated the fish community (74% of abundance). S. trutta was less abundant (16% of survey catch) but dominated the fish community (over 53%) in terms of biomass. S. trutta showed distinct diets (stomach content analysis) in the two rivers, and individuals from the larger river were notably more piscivorous, consuming native fish with a relatively small body size (<100-mm total length). Native fishes were isotopically distinct from S. trutta, which showed a wider isotopic niche in the smaller river, indicating that their trophic role was more variable than in the larger river (piscivorous). This study provides data from the unstudied pristine coastal rivers in Patagonia and reveals that interactions between native and introduced species can vary at very local spatial scales. 相似文献
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由于火山岩特殊的自然地理条件,其植被的组成与分布也具有特殊性。野外调查表明,湛江火山沟共有维管束植物238种,含种类较多的科为菊科、大戟科、禾本科、蝶形花科、桑科和芸香科。较重要的物种有大果榕、对叶榕、樟树、幌伞枫、假苹婆、桃金娘、野牡丹、鸭脚木、厚皮树等,它们在植被的组成与演替中起着举足轻重的作用。值得注意的是,外来入侵种在本区占有较大比例,这与本区的地理位置和日益增长的外贸、旅游交流等密切相关。该文对植被的组成、外来入侵种的危害作了分析与探讨,并提出了相应的保育措施。 相似文献
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Abstract Cades Cove, Great Smoky Mountains National Park, U.S.A. was historically cleared largely for pastoral purposes; it is now comprised of recently abandoned pastures dominated by non‐native pasture species. To investigate the potential for reducing non‐native species relative to native species, park managers initiated an experiment in 1995 that included mowing, herbicide application, planting of seed, and burning of replicate 20 × 50–m plots at each of two sites within Cades Cove. Between 1995 and 2001 we evaluated the response of the plant community (i.e., species‐specific cover and frequency, biomass, diversity) to this suite of treatments and compared it with unmanipulated control plots at each site. Four years after treatment initiation abundance measures of Plantago lanceolata, Setaria geniculata, and Trifolium spp. averaged one‐third lower in treated than control plots. Frequency of Festuca pratensis was lower in treated than in control plots for 2 years, but after 4 years its frequency, cover, and biomass did not differ between treated and control plots. By 2000 the cover of Sorghastrum nutans in treated plots increased to 23–47%, depending on the site. Total biomass and diversity increased in treated plots. The dominance of Lespedeza cuneata at one site apparently reduced planting success, biomass production, and diversity and evenness. Post‐treatment lags in response for several species, coupled with interannual variation in response to environmental conditions, suggest that evaluations of treatment success would differ greatly depending on when the evaluation was conducted. 相似文献
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Manipulating plant order of arrival, a process that creates priority effects, may be an unexplored powerful tool to hinder the establishment of invasive non‐native plants in sites under restoration. Knowledge and experimental studies on priority effects in the neotropics are scarce. Here, we propose a research agenda that investigates whether manipulating plant order of arrival can create priority effects in the neotropics, and if this strategy can be used to avoid the spread of undesired species in restoration projects. We also describe our view on expanding existing knowledge on priority effects to the neotropics and identifying key questions for future research. 相似文献