Ecogeographical analysis of the distribution of six Trifolium species in Sardinia

Collections of six species of Trifolium (Fabaceae) were made at 16 sites across the island of Sardinia in June/July 1998 and detailed ecogeographic information was recorded at each site. The six species collected were the inbreeding T. glomeratum, T. subterraneum and T. tomentosum, and the outcrossing T. nigrescens, T. michelianum and T. resupinatum. A principal components analysis and canonical variate analysis were conducted to group the sites, using the ecogeographical variables collected at each site. The variables that were found to be most important in grouping the sites were: mean January and July temperature, mean annual rainfall, latitude, longitude and soil pH. None of the six species were limited to only one ecogeographical group. However, it was often found to be only one or two variables that were determining their distribution. It is suggested that more detailed analysis of ecogeographic data of collection sites will become vital for improved planning of future collection missions, as the cost of collections and genetic erosion increases.     

Conservation and multivariate analysis utility in characterization of ecogegraphical relationships of Trifolium and Lotus species

The maintenance of species in an environment and the durability of rangeland and fallow improvement depend on the choice of populations used. The study of abundance and the relationship between the natural distribution of spontaneous legumes species of forage and/or pastoral interest and environmental factors is an important step for an adequate utilization of local genetic resources. Collection of annual Trifolium species and the genus of Lotus were conducted at 45 sites in Morocco in May/June 2004. Ecogeographical information was recorded at each site. Twelve species of annual Trifolium and two species of Lotus were identified. Most prolific were T. tomentosum and L. corniculatus. A principal components analysis and canonical variate analysis were conducted to group the sites, using the ecogeographical variables collected at each site. The variables that were found to be most important in grouping the sites were mean coldest month temperature, mean hottest month temperature, mean annual rainfall, latitude, longitude and soil pH. None of the species identified were limited to only one ecogeographical group.     

水菜花种群潜在生境选择与空间格局预测

国家二级保护野生植物水菜花(Ottelia cordata)，喜生于清洁的水环境中，对环境变化极为敏感，是检验湿地环境及气候变化的关键指示物种之一，在我国仅零星分布于海南北部的火山熔岩湿地区，生存状况不容乐观。研究水菜花种群潜在生境选择及其空间格局演变，有利于加强濒危物种保护保育及湿地生态系统修复、管理。该研究基于GIS平台和MaxEnt模型，结合气候、地形和土壤因子，探究水菜花种群环境限制因子及其在气候变化背景下潜在适宜生境的演变格局。结果表明，水菜花种群对温差与降水量变化敏感，等温性、最冷季度降水量、土壤类型和年均降水量对水菜花种群分布影响显著；全新世中期-当前-2070年气候变化背景下，水菜花适宜生境面积先减小后增大，分布重心呈西南-东北-西南转移格局；未来气候情景下，水菜花种群高度和中度适宜生境缩减，低适宜生境增加，南部地区将出现新增适宜生境，东北、西北及西南部适宜生境将发生消减。该研究从气候环境角度论证了水菜花种群的潜在生境选择及空间变化特征，可为濒危物种保护保育、湿地管理及其生物多样性维护工作提供参考和指导。     

藏北高原草地群落的数量分类与排序

采用TWINSPAN数量分类和DCA、CCA排序的方法,对藏北高原草地29个样点进行统计分析。结果显示:(1)TWINSPAN数量分类将藏北高寒草地群落划分成10种类型。(2)样点DCA排序第一轴基本反映了水分环境梯度,第二轴基本反映了热量梯度。(3)TWINSPAN分类所划分的各群落在DCA排序图上都有各自的分布范围和界限,说明DCA排序能较好的反应各优势群落与其环境资源之间的关系。(4)样点CCA排序表明,影响群落分布的首要环境因子是水分因子(年均降水量)和空间因子(经度),其次是热量因子(年均温度),CCA排序进一步阐明了群落分布决定于水分和温度等环境因子,并间接验证了TWINSPAN的分类结果。(5)物种CCA排序和TWINSPAN分类结果表明:植物群落中物种的分布格局与植物群落类型的分布格局存在一定的相似性。     

蒙古沙冬青群落区系组成及分类研究

蒙古沙冬青是西北地区珍稀濒危树种,探究区系组成和群落特征对于维持西北干旱荒漠区脆弱生态系统具有重要意义。该研究调查了26个蒙古沙冬青群落样地,采用TWINSPAN进行群落分类,同时利用典范对应分析(CCA)分析沙冬青群落物种组成与生态因子的关系,为珍稀濒危植物蒙古沙冬青的保护提供基础数据。结果表明:(1)蒙古沙冬青群落物种组成以豆科、禾本科、菊科和藜科植物为主,隶属于28科63属90种,区系组成以地中海、北温带分布及世界分布为主。(2)TWINSPAN等级分类可将26个蒙古沙冬青样地划分为9个群落类型,即蒙古沙冬青+蓍状亚菊群落、蒙古沙冬青+红砂群落、蒙古沙冬青+新巴黄耆群落、蒙古沙冬青+无芒隐子草群落、蒙古沙冬青+霸王群落、蒙古沙冬青+驼绒藜群落、蒙古沙冬青+白刺群落、蒙古沙冬青+沙鞭群落和蒙古沙冬青+毛刺锦鸡儿群落。(3)CCA排序分析显示,年均降雨量(F=2.8,P=0.002)、生长季降雨量(F=2.6,P=0.002)、速效氮(F=2.1,P=0.006)、太阳辐射量(F=2.1,P=0.008)、蒸汽压(F=1.9,P=0.006)、土壤有机质(F=1.7,P=0.04)、纬度(F=1.7,P=0.006)是影响蒙古沙冬青群落组成的主要生态因子。     

Species relationships and taxonomy inTulipa subg.Tulipa (Liliaceae)

Principal component and canonical variate analyses were used to analyse the variation of 34 morphological characters measured in 98 accessions ofTulipa subg.Tulipa, formerly known as sect.Leiostemones. In addition 43 accessions were analysed cytogenetically by means of C-banding methods. Based on the encountered variation and on geographical distribution data 30 species in five sections were recognized, of which the synonymy is stated. Seven new series in two different sections have been designated.     

我国原生植物假泽兰(菊科)的细胞学研究

该文研究了我国原生植物假泽兰(Mikania cordata)台湾花莲居群、苗栗居群、宜兰居群以及台北居群的染色体数目和染色体形态。结果表明:所有居群的染色体数目为2n=36,第一对染色体为近中部着丝粒染色体,其长臂中部具有次缢痕,显著大于其余染色体。各居群的核型公式皆为2n=18m+18sm,核型均为2B型,染色体内不对称性指数(A_1)的变化范围为0.38~0.39,染色体之间不对称性指数(A_2)的变化范围为0.30~0.32。此为我国假泽兰居群染色体数目的唯一报道,也是对该种核型的首次报道。结合前人对假泽兰染色体数目的研究结果,认为假泽兰存在种内非整倍性现象,但在中国台湾的居群中目前仅发现基于x=18的二倍体(2n=36)。假泽兰的第一对染色体的长臂中部具次缢痕,与假泽兰属已报道的核型相似,这一次缢痕可作为假泽兰属的细胞学标记。核型资料、野外观察以及ISSR数据显示薇甘菊(M.micrantha)在我国的成功入侵与入侵种和本土种之间的杂交渐渗无关。根据标本记录和野外考察结果,我国假泽兰现在的分布区与过去相比有了很大的缩减,推测生境的破坏和薇甘菊的侵入可能是导致假泽兰在中国台湾地区逐渐消失的主要原因。     

Morphological recognition of cryptic species in the planktonic foraminifer Orbulina universa

One of the key hypotheses of paleoceanography is that planktonic foraminiferal morphospecies record reasonably stable and homogeneous oceanographic and climatic characteristics over their geographic and stratigraphic ranges. The discovery of numerous genetically-defined cryptic species challenges the morphospecies concept in planktonic foraminifera and paleoceanographic interpretations based on them. Here, we present a combined genetic and biometric analysis of Orbulina universa specimens in the Atlantic, Indian and Pacific Oceans. Our study is based on shells retained after DNA extractions. On those genotyped shells, we perform biometric analyses (shell size and thickness, inner porosity and pore surface distribution). Our genetic data confirm the presence of three cryptic species of O. universa in the world ocean, whose distributions are primarily correlated to the productivity of the surface waters. The Mediterranean species of O. universa is most abundant in the vertically mixed and nutrient-rich areas of the low to mid-latitudes, whereas the Caribbean and Sargasso species occur in stratified and oligotrophic subtropical waters. Our biometric data show no correlation between shell size and inner porosity within each cryptic species of O. universa. Combining Principal Component Analyses with MANOVAs performed on shell pore surface distribution, we demonstrate that the three different cryptic species are characterized by significant morphological differentiation. The Caribbean species typically exhibits large pores and higher porosity values, while the Mediterranean and Sargasso species are characterized by smaller pore areas and shell porosity. A model based upon pore surface distribution correctly assigns 60% to 90% of the specimens to their corresponding genotype. Although the inner shell surface of the Sargasso species resembles that of the Mediterranean species, our model demonstrates that the pore surface distributions of these two cryptic species can be distinguished. Finally, the Sargasso species exhibits significantly thinner shells than the two other cryptic species.     

Floristic changes in the Castanopsis cuspidata var. sieboldii-forest communities along the Pacific Ocean coast of the Japanese Islands

The forest vegetation of Japan can be classified into three major regions: (1) the Camellietea japonicae evergreen broad-leaved forest region, e.g. Laurel forest which can be compared with the sclerophyllous gorest (durilignosa sensu Rübel, 1930), in the Mediterranean region, (2) the Fagetea crenatae summergreen Broad-leaved forest region, (3) the Vaccinio-Piceetea japonicae subalpine and subboreal conifer forest region. The distribution of these forest types on the Japanese Islands is related to both the warmth index, WI, and to the coldness index, CI, after Kira (1945). The borderline between the evergreen Camellietea japonicae and the summergreen Fagetea crenatae in Japan almost coincides with the 85°C line of WI. The chorological ariation of the forest vegetation in Japan and Korea shows a close correlation with the amount of warmth in the actual vegetation season.The evergreen broad-leaved Castanopsis cuspidata var. sieboldii forests can be classified into three major alliances; Quercion acuto-myrsinaefoliae, Maeso japonicae-Castanopsion sieboldii, and Psychotrioastanopsion sieboldii.The distribution limit of these three alliances on the Japanese Islands is again related to temperature. Changes in temperature and latitude correspond closely to changes in the Evergreen Broad-leaved Forests long the Pacific Ocean coast of the Japanese Islands. The three forest alliances differ in their number of evergreen and deciduous broad-leaved woody species, secondary forest types and syndynamic processes.Contribution from the Department of Vegetation Science, Institute of Environmental Science and Technology, Yokohama National University, No. 154.     

Comparative wood anatomy ofCoriaria

Wood anatomy ofCoriaria was surveyed to clarify generic features on the basis of 14 species collected from various regions of the World to cover the whole range of geographic distribution and habitual variation. Wood anatomy ofcoriaria is considerably uniform, and the species share a combination of the following features: 1) pores are thin-walled, polygonal in outline and mostly in multiples; 2) vessel elements and libriform fibers are very short; 3) perforation plates are exclusively simple; 4) intervessel pits are alternate; 5) vascular tracheids are present; 6) wood parenchyma is vasicentric and sometimes confluent; 7) rays are heterogeneous and large. Its species differ in several characters, such as distinctness of growth rings, pore size, pore patterns, type and abundance of wood parenchyma, and distinctness of storied structure. Comparisons among species indicate that the species of the Northern Hemisphere show a tendency toward having semi-ring porosity, while those of the Southern and Western Hemisphere have diffuse porosity. The other infrageneric variations appear to be related to different habits of the species rather than to geographic distribution. Small trees mostly have confluent and vasicentric parenchyma composed of fusiform cells and distinctly storied tissues, while shrubs and herbs have less abundant parenchyma which is vasicentric and comprises strands of two to four cells and indistinctly storied tissues.     

Stomatal conductance in a tropical xerophilous shrubland at a lava substratum

Diurnal variation in leaf stomatal conductance (g _s) of three xerophilous species (Buddleia cordata, Senecio praecox and Dodonaea viscosa) was measured over a 10-month period during the dry and wet seasons in a shrubland that is developing in a lava substratum in Mexico. Averaged stomatal conductances were 147 and 60.2 (B. cordata), 145 and 24.8 (D. viscosa) and 142.8 and 14.1 mmol m^–2 s^–1 (S. praecox) during the wet and dry season respectively. Leaf water potential () varied in a range of –0.6 to –1.2 (S. praecox), –0.6 to –1.8 (B. cordata) and –0.9 to –3.4 MPa (D. viscosa) during the same measurement periods. Stomata were more sensitive to changes in irradiance, air temperature and leaf–air vapour pressure difference in the rainy season than the dry season. Although stomatal responses to were difficult to distinguish in any season (dry or rainy), data for the entire period of measurement showed a positive correlation, stomata tending to open as increased, but there is strong evidence of isohydric behaviour in S. praecox and B. cordata. A multiplicative model relating g _s to environmental variables and to accounted for 79%–83% of the variation of g _s in three sites (pooled data); however, the performance of the model was poorer (60%–76%) for individual species from other sites not included in the pooled data.     

不同植被恢复类型的土壤肥力质量评价

科学确定森林土壤肥力指标并进行肥力质量的评价,对立地生产力和多目标森林经营的研究有着重要意义。以采伐(径级12 cm择伐)迹地上发育来的稀树灌丛、针叶林、针阔混交林和常绿阔叶林为研究对象,进行每木调查与群落分析,并比较各群落土壤因子间的差异,用典范对应分析(CCA)和因子分析对土壤肥力质量进行定量评价。结果表明,CCA可以有效地筛选土壤肥力质量指标,有助于质量指标的科学确定;土壤肥力质量综合评价分值为稀树灌丛(0.438)常绿阔叶林(0.414)针阔混交林(-0.170)针叶林(-0.331);演替初期(19 a)的植被恢复并未使土壤结构发生明显变化,土壤肥力质量是下降的;无人为干扰的3种群落类型,针叶林表现为更高的生物量积累,而天然更新的常绿阔叶林则更有利于生物多样性的增加与土壤养分的保蓄。     

Taxonomic notes on Mexican Ruellia (Acanthaceae)

The new nameRuellia comonduensis is provided for the species previously known asR. cordata Brandegee.Ruellia chilpancingana, a new species known only from Guerrero in southwestern Mexico, is described and compared to morphologically similar species. It is unique among Mexican species ofRuellia based on the following combination of characters: caducous bracteoles and secondary bracteoles, multiflowered dichasia from leaf axils, yellowish and cylindric-funnelform corollas, exserted stamens, and few (four or fewer) seeds per capsule. Macromorphological features and pollen ofR. chilpancingana are illustrated.     

Floristic patterns of epiphytes in the Brazilian Atlantic Forest,a biodiversity hotspot

To assess the main factors driving epiphytic angiosperm distribution throughout the Brazilian Atlantic Forest, we compiled 57 floristic surveys and analysed species composition under the influence of environmental variables, space and vegetation type using canonical correspondence analysis (CCA), similarity (Sorensen) and Mantel's tests. The indicator value index (IndVal) was used to find indicator species of each Brazilian Atlantic Forest vegetation type. Group sharpness analysis was performed in order to determine the appropriate group partition level. CCA showed a separation of the epiphytic flora reflecting temperature and rainfall gradients. Mantel's test showed that environment and space were highly correlated with floristic similarity. Cluster analysis, indicating floristic similarity, resolved five groups, mainly grouped by region. Clear differentiation of the Brazilian Atlantic Forest epiphytic flora on a north–south axis with a strong correlation with temperature and rainfall gradients was found. The role of space and environment on species composition varied according to distinct epiphytic species groups. In particular, for Bromeliaceae and Orchidaceae, the main factor associated with floristic similarity was space. Indicator species were found for all vegetation types apart from the Seasonal Semideciduous Forest that seemed to represent a subset of a more humid forest type. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 587–601.     

Ecological features affect patterns of plant communities in Mediterranean temporary rock pools

In this paper, the results of a study on the ecology, floristic composition and spatial assemblages of temporary limestone rock pool plant communities of a central Mediterranean area (S Sicily, the Maltese Islands and Lampedusa) are presented. A total of 76 temporary pools were studied, distributed between the infra-mediterranean and thermo-mediterranean bioclimatic belt. For each temporary rock pools, the floristic composition and cover of the species were determined using standard relevé methods. Moreover, for 50 of these pools, pH, conductivity, soil depth, water-level, altitude and floristic richness and diversity index were assessed. The plant communities were analysed using unweighted pair group method using arithmetic averages and Euclidean distance classification and ordination methods such as canonical correspondence analysis (CCA). A total of four plant communities with specific floristic composition were established, each one with a different dominant species: Callitriche truncata; Elatine gussonei; Tillaea vaillantii and Lythrum hyssopifolia. According to the CCA, the spatial patterns of plant communities follow an ecological gradient related to water level and depth/size of the rock pools: these are the main ecological features affecting the distribution of the plant communities of rock pools. In addition, floristic richness and diversity index showed a slight increase in trend from temporary pools submerged for long periods towards pools submerged for short periods.     

The ecological significance of phenology in four different tree species: effects of light and temperature on bud burst

The process of adaptation is the result of stabilising selection caused by two opposite forces: protection against an unfavourable season (survival adaptation), and effective use of growing resources (capacity adaptation). As plant species have evolved different life strategies based on different trade offs between survival and capacity adaptations, different phenological responses are also expected among species. The aim of this study was to compare budburst responses of two opportunistic species (Betula pubescens, and Salix x smithiana) with that of two long-lived, late successional species (Fagus sylvatica and Tilia cordata) and consider their ecological significance. Thus, we performed a series of experiments whereby temperature and photoperiod were manipulated during dormancy. T. cordata and F. sylvatica showed low rates of budburst, high chilling requirements and responsiveness to light intensity, while B. pubescens and S. x smithiana had high rates of budburst, low chilling requirements and were not affected by light intensity. In addition, budburst in B. pubescens and S. x smithiana was more responsive to high forcing temperatures than in T. cordata and F. sylvatica. These results suggest that the timing of growth onset in B. pubescens and S. x smithiana (opportunistic) is regulated through a less conservative mechanism than in T. cordata and F. sylvatica (long-lived, late successional), and that these species trade a higher risk of frost damage for the opportunity of vigorous growth at the beginning of spring, before canopy closure. This information should be considered when assessing the impacts of climate change on vegetation or developing phenological models.     

Life histories of desert geophytes —the demographic consequences of reproductive biomass partitioning patterns

Summary During five consecutive growing seasons (winters) ca. 110 plants of the desert geophyte Bellevalia desertorum were marked individually in a 25 m² plot on a south-facing slope in the central Negev Desert of Israel. The number of rosette leaves of each plant was recorded, as well as whether it flowered and produced seeds. Multiple regression analysis of the data on the B. desertorum individuals showed that the reproductive state of a plant was determined by 1) its previous size and 2) the current conditions (rainfall), but not by previous conditions, nor by previous reproductive activity. Plant surveys supported these findings. These demographic results were consistent with the current understanding of the reproductive resource allocation pattern of B. desertorum. Flowering was most affected by rainfall until January of the same season, the number of leaves by rainfall until March and seed set was by the total annual amount. Surveys in populations ofB. eigii, a species of more mesic habitats in the Negev Desert suggested that in this species there is a negative effect of previous reproduction in combination with the previous and current conditions, which is also expected from its biomass partitioning pattern.The significance of demographic studies of individual plants in natural populations for the interpretation of experimentally determined resource partitioning patterns was discussed.     

大果马蹄荷(Exbucklandia tonkinensis)群落的纬度地带性

大果马蹄荷主产南亚热带至中亚热带南缘,南至海南岛,北至罗霄山脉中段的井冈山、桃源洞地区,是常绿阔叶林的特征种。以纬度地带性(海南霸王岭、广东黑石顶、广东南岭、江西金盆山、江西井冈山、湖南桃源洞)为依托,选定6个具代表性的大果马蹄荷群落开展群落生态学研究,结果表明:(1)各样地物种多样性较高,尤以金盆山蕨类植物9科10属11种、种子植物42科78属128种和桃源洞蕨类植物9科11属12种、种子植物41科79属134种最为丰富。群落组成的优势科主要为金缕梅科、壳斗科、樟科、山茶科、杜鹃花科、山矾科等。(2)从区系特征和环境梯度看,大果马蹄荷群落以南亚热带为分布中心,向南或向北其物种多样性Simpson指数、Shannon-Wiener指数及相应的均匀度指数均呈下降趋势,其中霸王岭、黑石顶、南岭、金盆山、井冈山、桃源洞的Shannon-Wiener指数分别为3.453、4.021、4.130、3.790、3.415、3.712。(3)群落相似性聚类分析显示群落随纬度和随海拔高度形成两个梯度系列,一是以黑石顶、金盆山、井冈山、桃源洞的纬度地带性为一支,相似性系数0.51;二是以南岭和霸王岭聚成海拔梯度较高的另一支,但其相似性系数0.50,为0.33—0.48。(4)大果马蹄荷群落种类组成在区系性质上很相似,具有明显的南亚热带特征;同时,受海拔、地形、气温、降雨条件等因素的影响,种子植物属的热带成分随纬度增加而呈波动性下降趋势。(5)大果马蹄荷种群在各群落中的重要值水平和径级结构表现出一致性,在纬度地带性差异上无明显的相关性。霸王岭大果马蹄荷的径级结构为增长型,但重要值排名为32,说明向南分布该种群优势度明显下降;在南岭、黑石顶、金盆山、桃源洞该种群优势度较大,且为稳定型种群;在井冈山该群落受到人为干忧,大果马蹄荷的重要值排名第1,但为衰退型种群。     

Areography of the genus Dendroctonus (Coleoptera: Curculionidae: Scolytinae) in Mexico

Objective To analyse whether the geographical ranges of Dendroctonus species are (1) associated with factors such as host species or elevation, and (2) in agreement with Halffter's Nearctic distribution pattern. (3) To identify and discuss the factors that are likely to act as barriers to the genus’ geographical distribution. (4) To explore whether there is an association between the size of the geographical ranges of Dendroctonus species and the number of Pinus host species used by each of them, and (5) to assess if these host species are most common at the elevations preferred by the individual Dendroctonus species. Site Mexico. Methods Records of 12 species of Dendroctonus were gathered from entomological collections in Mexico. Distribution ranges were defined by using the propinquity method ( Rapoport, 1975a ). Analysed parameters were: (1) geographical distribution of single species, (2) overlapping of species ranges, (3) disjunction patterns and barriers by means of isoprobabilistic lines, based on the morphotectonic subdivision of Mexico ( Ferrusquía‐Villafranca, 1998 ), (4) spatial variation in species richness with respect to latitude and altitude, (5) size of geographical ranges, and (6) host species for each Dendroctonus species. A correlation was determined between area size and number of pine host species. Results The species ranges varied in shape and size. Geographical ranges tend to be discontinuous in shape. Composite patterns showed that disjunctions among ranges do not closely follow Mexico's morphotectonic subdivision. There are repeated discontinuities among individual distributions, which define five areas: (1) Baja California Peninsula, (2) Sierra Madre Occidental (SMOC), (3) northern Sierra Madre Oriental (SMOR), (4) Sierra Madre de Chiapas, and (5) SMOR + Faja Volcanica Transmexicana (FVT) + Sierra Madre del Sur. The isoprobabilistic lines confirm that the inner part of SMOC provides an optimal environment for the genus, and the FVT province constitutes the broader corridor for it in the country. Richness does not directly decrease or increase with latitude. Richness behaviour of the insect is not associated with that of its host. Elevation distributions showed that most Dendroctonus species move within broad margins of tolerance and species richness is concentrated in the montane interval. Dendroctonus attack 24 of the 47 Pinus species distributed in Mexico. Preferred pine species belong predominantly to Leiophyllae, Ponderosae and Oocarpae subsections. The Spearman rank correlation between area size and number of pine host species was not significant. Dendroctonus clearly belongs to a Nearctic distribution pattern (sensu Halffter, 1987 ). Main conclusions Dendroctonus is present in all montane systems of Mexico and its species coexist within a high geographical sympatry. Overlapping of species distribution appears to be the result of two elements – generalized polyphagy inside Pinus and a wide elevation tolerance within mountainous environments. This behaviour, linked to a high vagility, has allowed the genus Dendroctonus to expand its distribution across Mexico and to employ mountainous systems as corridors separated by barriers that exert a low selective filter effect.