祁连山东部森林林分结构和环境因素对草本物种多样性的影响

林下草本物种多样性在维持西北干旱与半干旱地区的生态系统服务功能方面起着重要作用,探究其相关影响因素,可为祁连山东部地区的人工生态公益林的可持续经营提供理论基础。选取位于祁连山东部地区的针叶纯林、阔叶纯林、针叶混交林、针阔混交林(人工林)为研究对象,在相关性分析的基础上构建草本物种多样性的多因素参数预测模型和结构方程非参效应模型,探究多重因素(林分空间结构、林分非空间结构、环境因子)间的关系以及对林下草本物种多样性的影响程度。结果表明:(1)针阔混交林中林下草本的科、属、种数量最多。(2)平均胸径、平均树高、角尺度、混交度、大小比、坡度与草本物种多样性呈显著性相关(P<0.05)。(3)平均胸径是影响林下草本Simpson多样性指数的关键因子;坡度是影响林下草本Shannon-Wiener多样性指数的关键因子;角尺度、混交度是影响Pielou均匀性指数的关键因子;平均胸径、平均树高是影响物种丰富度的关键因子。(4)结构方程非参效应模型显示林分结构是影响草本物种多样性的关键因子(P<0.001),环境因子是影响草本物种多样性的重要因子(P<0.05)。因此,在后续森林植被恢复措施中,应当着重考虑林分的空间结构,形成随机分布的异龄复层混交林,以增加光合利用效率并遵循生态位互补理论,从而提高草本多样性。     

Late Quaternary climate legacies in contemporary plant functional composition

The functional composition of plant communities is commonly thought to be determined by contemporary climate. However, if rates of climate‐driven immigration and/or exclusion of species are slow, then contemporary functional composition may be explained by paleoclimate as well as by contemporary climate. We tested this idea by coupling contemporary maps of plant functional trait composition across North and South America to paleoclimate means and temporal variation in temperature and precipitation from the Last Interglacial (120 ka) to the present. Paleoclimate predictors strongly improved prediction of contemporary functional composition compared to contemporary climate predictors, with a stronger influence of temperature in North America (especially during periods of ice melting) and of precipitation in South America (across all times). Thus, climate from tens of thousands of years ago influences contemporary functional composition via slow assemblage dynamics.     

上海城市森林草本植物多样性的城乡分布格局

林下草本植物是城市森林生物多样性重要的保育层,敏感度高,可塑性强,能有效反映城市植被对城市化的响应策略。本研究在上海市范围内沿中心城区—近郊—远郊的城乡梯度,共选取16块林地共398个样方,分析了上海市森林草本群落区系特征和多样性格局沿城乡梯度的变化规律。结果表明:上海城市森林生态系统中共有草本植物144种,隶属47科118属;多年生草本74种,占半数以上(51.39%);属和种分别涵盖18和12个分布区类型和亚型,以热带和温带成分为主;外来植物28种,占比接近20%;物种丰富度和群落多样性指数均沿中心城区—近郊—远郊梯度先下降后上升,近郊最低,远郊最高;中心城区物种构成与远郊相似,与近郊差异最大。本研究揭示了城市森林生态系统中草本植物的分布格局以及多样性沿城乡梯度的变化规律,为深入开展城市化与城市植被的互作研究提供了理论支撑,为管理部门制定相关政策提供了科学依据。     

高寒草地植物物种多样性与功能多样性的关系

物种多样性与功能多样性的关系是生态学当前研究的热点问题之一,不同区域典型生态系统物种多样性和功能多样性的关系研究有利于生物多样性保护理论的全面发展。以青藏高原地区的主要草地生态系统—高寒草甸和高寒草原为研究对象,采用4个物种多样性指数(Patrick丰富度指数、Shannon-Weiner多样性指数、Pielou均匀度指数和Simpson优势度指数)和9个功能多样性指数(FAD功能性状距离指数、MFAD功能性状平均距离指数、基于样地的FDp和基于群落的FDc功能树状图指数、FRic功能体积指数、FEve功能均匀度指数、Rao功能离散度常二次熵指数、FDiv功能离散指数、FDis功能分散指数),分析了高寒草地植物物种多样性、功能多样性关系及其与初级生产力的关系,以期阐明3个科学问题:不同草地类型的高寒草地生态系统植物物种多样性和功能多样性有何差异?高寒草地生态系统的植物物种多样性和功能多样性有何关系?高寒草地生态系统物种多样性、功能多样性对生态系统功能的影响有何异同?研究结果表明:(1)与高寒草原相比,高寒草甸具有更高的物种多样性、功能丰富度和功能离散度;(2)高寒草甸中,Patrick丰富度与功能丰富度指数(FAD、MFAD、FDp、FDc)和功能离散度指数(FDiv)的具有较强的相关性,最优拟合方程分别为幂函数和二次多项式函数;(3)高寒草原中,Patrick丰富度与功能丰富度指数(FAD、MFAD、FDp、FDc、FRic)、Shannon指数和Simpson指数与FEve指数的相关性较强,最优拟合方程为二次多项式函数,Pielou指数与FEve指数的相关性较强,最优拟合方程为指数函数;(4)高寒草甸的初级生产力分别与物种丰富度指数Patrick、功能离散指数FDiv具有较强的相关性;而高寒草原的初级生产力与4个物种多样性指数间均具有较强的相关性,与功能离散指数FDiv具有较强的相关性,最佳拟合方程均为二次多项式函数。研究的总体结论为:物种多样性、功能多样性、二者之间的关系以及二者与生态系统服务功能(以初级生产力为例)之间的关系在高寒草甸和高寒草原群落中表现迥异,因此在研究青藏高原高寒草地的生态功能时,不能仅仅测度传统的物种多样性,还应测度与物种多样性、生态功能密切相关的功能多样性。     

浙北地区不同土地利用下乡村草本层植物多样性研究

该文以浙江省安吉县两个典型乡村—繅舍村和赋石村为例,选取公园、农耕区、河道、人工林地四种不同土地利用类型,用Shannon-Wiener指数、Simpson指数、Sorensen指数为标识多样性的指标,分析不同生境下草本植物多样性差异。结果表明：乡村生境中共记录物种162种,分属47科123属,其中禾本科与菊科物种数占总数的31.48％;农耕区生境的Shannon-Wiener指数、Simpson指数最高,分别为2.76和0.91,农耕区与河道的Sorensen指数最高为0.57。从农耕区、河道、公园到林地生境,草本物种多样性整体呈减小趋势。另外,发现人工绿化措施会导致草本物种减少,如从种植水稻单一作物到复合作物,草本层植物随之改变。单一稻田与复合种植区比较,草本植物主要的科属组成无明显变化,莎草科、菊科、禾本科植物仍占主体;但草本植物群落主要物种组成发生变化,稻田转变成农耕区后,牛筋草、黑麦草,碎米荠、小飞蓬、喜旱莲子草成为草本层群落主要构成植物,水竹叶覆盖度减少,小飞蓬和喜旱莲子草的覆盖度增加。此外,还发现4种生境中共有喜旱莲子草、加拿大一枝黄花、土荆芥三种入侵物种,但未能对本土物种构成显著影响。这表明不同土地利用方式会严重影响草本群落物种组成及物种多样性;土地利用方式的变化,会引起草本植物主要群落构成发生改变;土地利用类型的多样化有利于本土草本物种多样性生存。该研究结果有助于为城镇化进程中保护乡村植物多样性、加速推进美丽中国建设提供技术支撑。     

Monitoring shifts in plant diversity in response to climate change: a method for landscapes

Improved sampling designs are needed to detect, monitor, and predict plant migrations and plant diversity changes caused by climate change and other human activities. We propose a methodology based on multi-scale vegetation plots established across forest ecotones which provide baseline data on patterns of plant diversity, invasions of exotic plant species, and plant migrations at landscape scales in Rocky Mountain National Park, Colorado, USA. We established forty two 1000-m² plots in relatively homogeneous forest types and the ecotones between them on 14 vegetation transects. We found that 64% of the variance in understory species distributions at landscape scales were described generally by gradients of elevation and under-canopy solar radiation. Superimposed on broad-scale climatic gradients are small-scale gradients characterized by patches of light, pockets of fertile soil, and zones of high soil moisture. Eighteen of the 42 plots contained at least one exotic species; monitoring exotic plant invasions provides a means to assess changes in native plant diversity and plant migrations. Plant species showed weak affinities to overstory vegetation types, with 43% of the plant species found in three or more vegetation types. Replicate transects along several environmental gradients may provide the means to monitor plant diversity and species migrations at landscape scales because: (1) ecotones may play crucial roles in expanding the geophysiological ranges of many plant species; (2) low affinities of understory species to overstory forest types may predispose vegetation types to be resilient to rapid environmental change; and (3) ecotones may help buffer plant species from extirpation and extinction.     

秸秆覆盖量对红壤旱地棉花生长及土壤温度的影响

为探索红壤旱地较适宜的秸秆覆盖量,采取随机区组大田试验,设置4个秸秆覆盖水平:S1为0 kg/hm~2、S2为4375 kg/hm~2,S3为8750 kg/hm~2和S4为13125 kg/hm~2,研究秸秆覆盖量对红壤旱地棉花产量、出苗率、株高、叶绿素含量和土壤温度的影响。结果表明:秸秆覆盖处理(S2—S4)较不覆盖处理(S1),一是提高棉花出苗率,差异极显著(P0.01);二是影响棉花生育后期的主茎生长速度,以S4效果最好;三是可明显促进棉花叶绿素含量的增加,且以S3和S4的效果较好;四是调节土壤温度,在8:00和20:00提高土壤温度,在14:00降低土壤温度,且日均地温变化幅度小,但随着土层的加深,调温作用逐渐减弱,整个覆盖期内日均温的差值与土壤深度具有高度的相关性;五是显著增加棉花产量,S2、S3和S4分别比S1高11.4%、35.9%和37.7%,差异极显著(P0.01),且随着覆盖量的增加,增产效果逐渐提高。综合来看,秸秆覆盖在改善红壤旱地棉花产量、出苗率、株高、叶绿素含量、调节土壤温度方面发挥着重要作用,且以8750—13125 kg/hm~2效果显著,是红壤旱地值得推广的栽培模式。     

Using niche-based modelling to assess the impact of climate change on tree functional diversity in Europe

Rapid anthropogenic climate change is already affecting species distributions and ecosystem functioning worldwide. We applied niche-based models to analyse the impact of climate change on tree species and functional diversity in Europe. Present-day climate was used to predict the distributions of 122 tree species from different functional types (FT). We then explored projections of future distributions under one climate scenario for 2080, considering two alternative dispersal assumptions: no dispersal and unlimited dispersal. The species-rich broadleaved deciduous group appeared to play a key role in the future of different European regions. Temperate areas were projected to lose both species richness and functional diversity due to the loss of broadleaved deciduous trees. These were projected to migrate to boreal forests, thereby increasing their species richness and functional diversity. Atlantic areas provided an intermediate case, with a predicted reduction in the numbers of species and occasional predicted gains in functional diversity. This resulted from a loss in species within the broadleaved deciduous FT, but overall maintenance of the group. Our results illustrate the fact that both species-specific predictions and functional patterns should be examined separately in order to assess the impacts of climate change on biodiversity and gain insights into future ecosystem functioning.     

中温型和暖温型草原五种植物构件生长与水热组合关系研究

在暖温型和中温型草原对大针茅(Stipa grandis)、羊草(Leymus chinensis)、糙隐子草(Cleistogeness quorrosa)、达乌里胡枝子(Lespedeza dahurica)和阿尔泰狗哇花(Heteropappus altaicus)5个共有植物种群的构件生长特征进行了比较研究,并应用种群统计的生长分析指标与研究站点的月平均温度、降水量和湿润度进行了灰色关联分析.结果表明,中温型草原各共有种的相对生长速率(DRGR &DRGRa)和单位叶速率(DULA)均高于暖温型草原,显示出对中温型草原生长季短、热量条件不足的生态适应特征;而暖温型草原则以较长的叶面积及构件持续时间适应该草原区生长季长、热量较为充足的气候条件.暖温型草原各共有种的构件生长指标与湿润度之间的灰色关联度普遍高于中温型草原,即暖温型草原植物的构件生长对生长季内的水热组合更为敏感,显示出不同热量型草原区植物构件生长的响应特征.     

干扰对植物群落物种组成及多样性的影响

在介绍了干扰的概念及其性质和干扰对物种多样性影响的有关假说基础上,以森林干扰为主要对象,探讨了干扰对植物群落物种组成的影响,并从干扰类型、干扰强度和干扰频率等几个方面阐述了干扰对植物群落物种多样性的影响;另外,还分析了重要的小尺度干扰——林隙在该方面的影响。分析总结出干扰对植物群落的影响差异主要与干扰特征、植物群落特征及植物的生物学特性和受干扰地点的资源条件有关。最后,总结分析了国内外在该方面研究存在的问题,并对今后研究提出一些建议,为相关工作提供参考。     

Effects of nitrogen addition on the plant diversity and biomass of degraded grasslands of Nei Mongol,China

人为干扰及气候变化导致内蒙古草地发生了大面积退化, 氮添加是促进退化草地生产力恢复的一项重要措施。该文基于2011年建立的氮肥添加实验平台, 以3个不同退化程度(中度退化、重度退化、极度退化)草地群落为研究对象, 设置对照、10、20、30、40和50 g·m ^-2·a ^-1 6种氮添加处理, 分析氮添加对退化草地恢复过程中群落多样性和生物量的影响。结果表明: (1)氮添加降低了中度、重度退化草地恢复进程中物种丰富度和多样性, 对极度退化草地恢复进程中物种丰富度和多样性无明显影响。(2)氮添加促进了3个不同退化程度草地恢复进程中群落地上生物量的增加。(3)氮添加显著增加了群落中禾草的地上生物量及其在群落地上生物量中所占的比例, 降低了杂类草在群落地上生物量中的比例, 但对杂类草地上生物量无显著影响。研究表明在利用施肥措施治理退化草地的过程中, 需要充分考虑草地退化程度以及由氮添加引起的群落多样性和生产力的改变对草地生态系统功能的影响。     

氮添加对内蒙古退化草地植物群落多样性和生物量的影响

人为干扰及气候变化导致内蒙古草地发生了大面积退化, 氮添加是促进退化草地生产力恢复的一项重要措施。该文基于2011年建立的氮肥添加实验平台, 以3个不同退化程度(中度退化、重度退化、极度退化)草地群落为研究对象, 设置对照、10、20、30、40和50 g·m ^-2·a ^-1 6种氮添加处理, 分析氮添加对退化草地恢复过程中群落多样性和生物量的影响。结果表明: (1)氮添加降低了中度、重度退化草地恢复进程中物种丰富度和多样性, 对极度退化草地恢复进程中物种丰富度和多样性无明显影响。(2)氮添加促进了3个不同退化程度草地恢复进程中群落地上生物量的增加。(3)氮添加显著增加了群落中禾草的地上生物量及其在群落地上生物量中所占的比例, 降低了杂类草在群落地上生物量中的比例, 但对杂类草地上生物量无显著影响。研究表明在利用施肥措施治理退化草地的过程中, 需要充分考虑草地退化程度以及由氮添加引起的群落多样性和生产力的改变对草地生态系统功能的影响。     

竹叶眼子菜种群遗传多样性与群落物种多样性关系的研究

以洪湖中的沉水植物群落及其优势种竹叶眼子菜(Potamogeton wrightii Morong)为研究对象,利用AFLP分子标记结合野外调查的方法,分析保护区(干扰较小)与非保护区(干扰较大,敞水区)中沉水植物群落的物种多样性与竹叶眼子菜遗传多样性之间的相关性。结果显示:洪湖沉水植物群落物种丰富度(S)和物种多样性辛普森指数(D)在保护区和非保护区均未发现显著性差异;竹叶眼子菜的重要值(IV)在保护区(5.2%~23.2%)较非保护区(8.5%~73.3%)稳定。竹叶眼子菜的遗传多样性在两个区未发现显著差异,其遗传多样性与群落物种多样性这两个指标在保护区、非保护区及全湖水平均不相关,说明沉水植物群落的物种多样性和竹叶眼子菜的遗传多样性对不同环境干扰的响应有所差异。     

Multifunctionality debt in global drylands linked to past biome and climate

Past vegetation and climatic conditions are known to influence current biodiversity patterns. However, whether their legacy effects affect the provision of multiple ecosystem functions, that is, multifunctionality, remains largely unknown. Here we analyzed soil nutrient stocks and their transformation rates in 236 drylands from six continents to evaluate the associations between current levels of multifunctionality and legacy effects of the Last Glacial Maximum (LGM) desert biome distribution and climate. We found that past desert distribution and temperature legacy, defined as increasing temperature from LGM, were negatively correlated with contemporary multifunctionality even after accounting for predictors such as current climate, soil texture, plant species richness, and site topography. Ecosystems that have been deserts since the LGM had up to 30% lower contemporary multifunctionality compared with those that were nondeserts during the LGM. In addition, ecosystems that experienced higher warming rates since the LGM had lower contemporary multifunctionality than those suffering lower warming rates, with a ~9% reduction per extra degree Celsius. Past desert distribution and temperature legacies had direct negative effects, while temperature legacy also had indirect (via soil sand content) negative effects on multifunctionality. Our results indicate that past biome and climatic conditions have left a strong “functionality debt” in global drylands. They also suggest that ongoing warming and expansion of desert areas may leave a strong fingerprint in the future functioning of dryland ecosystems worldwide that needs to be considered when establishing management actions aiming to combat land degradation and desertification.     

DNA from soil mirrors plant taxonomic and growth form diversity

Ecosystems across the globe are threatened by climate change and human activities. New rapid survey approaches for monitoring biodiversity would greatly advance assessment and understanding of these threats. Taking advantage of next-generation DNA sequencing, we tested an approach we call metabarcoding: high-throughput and simultaneous taxa identification based on a very short (usually <100 base pairs) but informative DNA fragment. Short DNA fragments allow the use of degraded DNA from environmental samples. All analyses included amplification using plant-specific versatile primers, sequencing and estimation of taxonomic diversity. We tested in three steps whether degraded DNA from dead material in soil has the potential of efficiently assessing biodiversity in different biomes. First, soil DNA from eight boreal plant communities located in two different vegetation types (meadow and heath) was amplified. Plant diversity detected from boreal soil was highly consistent with plant taxonomic and growth form diversity estimated from conventional above-ground surveys. Second, we assessed DNA persistence using samples from formerly cultivated soils in temperate environments. We found that the number of crop DNA sequences retrieved strongly varied with years since last cultivation, and crop sequences were absent from nearby, uncultivated plots. Third, we assessed the universal applicability of DNA metabarcoding using soil samples from tropical environments: a large proportion of species and families from the study site were efficiently recovered. The results open unprecedented opportunities for large-scale DNA-based biodiversity studies across a range of taxonomic groups using standardized metabarcoding approaches.     

On the relationship between plant species diversity and genetic diversity of Plantago lanceolata (Plantaginaceae) within and between grassland communities

Aims and Methods The relationship between genetic diversity and species diversity and the underlying mechanisms are of both fundamental and applied interest. We used amplified fragment length polymorphism (AFLP) and vegetation records to investigate the association between genetic diversity of Plantago lanceolata and plant species diversity using 15 grassland communities in central Germany. We used correlation and partial correlation analyses to examine whether relationships between genetic and species diversity were direct or mediated by environmental differences between habitats.Important findings Both within- and between-population genetic diversity of P. lanceolata were significantly positively correlated with plant species diversity within and between sites. Simple and partial correlations revealed that the positive correlations indirectly resulted from the effects of abiotic habitat characteristics on plant species diversity and, via abundance, on genetic diversity of P. lanceolata. Thus, they did not reflect a direct causal relationship between plant species diversity and genetic diversity of P. lanceolata, as would have been expected based on the hypothesis of a positive relationship between plant species diversity and niche diversity.