Elevation patterns of woody taxa richness in the evergreen Afromontane vegetation of Ethiopia

Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricted to small areas or single/few Mountains. Moreover, there is no general consensus on the patterns of woody taxa distribution by elevation. The objectives of this study were to examine the elevation patterns of woody taxa richness and their relationship with elevation in the AFE. Data were collected and compiled from the Flora of Ethiopia and Eritrea (Vols. 1-7). About 5918 plant species of 243 families were examined and their elevational distributions were recorded. The distributional ranges of woody taxa were aggregated at 19 points (sites) at 100?m intervals starting from 1500 to 3400?m a.s.l. Single-factor analysis of variance (one-way ANOVA) was used to test the hypothesis that mean species richness of woody taxa decreases from the lower to the upper limit of AFE. Simple linear correlation and regression were used to show the relationships of woody taxa richness with elevation. We documented the presence of 505 woody taxa (441 species, 31 subspecies and 33 varieties) representing 267 genera and 90 families in the AFE. In terms of habit, 279 taxa are shrubs, 178 are trees and 48 are lianas. The distribution of woody taxa (trees, shrubs and lianas) showed a slight increase at the lower portion and a monotonic decline with increasing elevation. Species richness of trees, shrubs and lianas was negatively and significantly correlated with elevation (r?=??0.985, ?0.984, ?0.981, respectively; all p?<?0.001). Our hypothesis was accepted because mean richness significantly decreased from the lower to the upper limit of AFE (p?<?0.001). Generally, monotonic patterns of decline in richness were observed for trees, shrubs and lianas. The contribution of shrubs to total richness increased with increasing elevation whereas that of trees and lianas decreased.

Gnetifolin L and O, Two Dimeric Stilbenes from Gnetum Montanum

Two new dimeric stilbenes, named gnetifolin L and gnetifolin O, were isolated from the alcoholic extract of lianas of Gnetum montanum. Their structures were elucidated mainly on the basis of spectroscopic data including 2D-NMR studies on peracetate derivatives.

Diversity, distribution and resource values of woody climbers in tropical forests of southern Eastern Ghats, India

We investigated the distribution and resource values of liana species assessed in six hill complexes of southern Eastern Ghats, India. 143 liana species （DBH （diameter at breast height） ≥1.5 cm） and 32,033 liana individuals were recorded from 110 transects （0.5 ha each covering 55 ha area） in the study sites. The resource values of lianas were broadly categorized into ecological and economic importance. About 90% （129） of liana species and 96% （30,564） of liana individuals were established ecological/economic values. Fruit rewards provided by 76 species and 20,325 individuals constituted the major resource of ecological importance. 82 species and 21,457 liana individuals are of economic importance as medicine, edible fruits, edible and medicinal values, and yet others are used for different domestic purposes including furniture, fuel wood, rope making etc.. Ecologically, the prevalence of succulent diaspores in lianas of Indian Eastern Ghats indicates the animal dependence of many liana species for dispersal and underlines the need for a holistic and whole-forest conservation approach in maintaining forest biodiversity.

Woody species composition and structure of Kuandisha afromontane forest fragment in northwestern Ethiopia

To investigate the woody species composition,diversity and structure of Kuandisha Afromontane forest,vegetation and environmental data were collected from 53 plots of 10 m 9 50 m for trees and shrubs and 265 subplots of 2 m 9 4 m for seedlings were laid along eight transect lines. The local name, scientific name, abundance,DBH, height and percentage foliage cover of species were recorded. Environmental variables, namely altitude, latitude and longitude as well as disturbance levels were also recorded in each plot. Structure, basal area, importance value index（IVI） and species prioritization were analyzed using spreadsheet programs. Correlation coefficients, frequency, relative frequency, Shannon diversity index,Shannon evenness and vegetation classification were analyzed using an R package. Sixty-six species belonging to40 families were recorded. Fabaceae was the most diverse family consisting of seven species, followed by Euphorbiaceae and Asteraceae. In terms of habit, 29 species were trees, 28 were shrubs, and 9 were lianas. The overall Shannon diversity index was 2.5. The frequency and relative frequency of woody species with DBH C2.5 cm ranged from 1.9 to 92.5 and 0.1 to 5, respectively. Seedling density varied among species ranging from five to 9938 individuals ha-1. The total basal area of woody species having DBH C2.5 cm is 15.3 m2ha-1. The IVI of species ranged from 0.13 for Solanum giganteum Jacq. to 28.4 for Croton macrostachyus Del. The woody vegetation was classified into five community types. Species richness,diversity and evenness of communities were strongly positively correlated. On the other hand, the correlation between disturbance and seedling density, and species richness was strongly negative. Thus, among the recorded woody species, a significant portion was either lacking regeneration or selectively removed for various purposes.The lack of seedlings of those species is mainly attributed to anthropogenic disturbances particularly free grazing. As a result, 14 tree, seven shrub and one liana species were prioritized for conservation and management interventions.

Impacts of forest management on liana diversity and community structure in a tropical forest in Ghana:implications for conservation

We studied the impacts of liana cutting as a forest management tool on liana diversity （species richness, Shannon diversity index） and community structure （diam- eter distribution, basal area, species dominance） in the Asenanyo Forest Reserve, Ghana. Two types of silvicul- turally treated forests were studied： Logging treated （LT） and Tropical Shelterwood System （TSS） treated forests. An untreated primary forest was included as a control, result- ing in three forest management systems. Lianas with diameter 〉2 cm were identified in ten 40 × 40 m2 plots within each management system. Liana cutting signifi- cantly reduced liana species richness, Shannon diversity index, and basal area in the LT forest after two decades. However, liana species richness and basal area werecomparable in the TSS treated and untreated forests, indi- cating significant recovery in the former after over six decades. Sφrensen similarity index of liana species com- position between the untreated forest and each of the treated forests was moderate. Our findings suggest that liana cutting most likely influenced the dominance of some liana species. In view of the adverse impact of blanket liana cutting on liana diversity, selective liana cutting is rec- ommended as a means of controlling liana numbers while maintaining liana diversity.

A Left-Handed, Stem-Twining Plant from the Miocene Shanwang Formation of Eastern China

Twining stems of plants are very common in extant tropical and subtropical forests, and the climbing growth habit of plants may be an evolutionary innovation and ecological adaptation to either closed, shady or open, edge environments. However, the origin of handedness in climbing plants remains unclear. Here we report a Miocene (ca. 16 million years ago) macrofossil from the Shanwang Formation of Shandong Province, Eastern China, unequivocally exhibiting the first direct fossil evidence for a left-handed, stem-twining growth habit in plants. This fossil plant bears a thicker, slightly curved supporting stem (2 - 3.5 mm wide), which is loosely, spirally twined by a thinner stem (1.5 - 2 mm wide), possibly representing part of distal branches from a liana or vine.

Effects of human disturbance on liana community diversity and structure in a tropical rainforest, Malaysia: implication for conservation

Aim Due to the important role of lianas in the functioning of forest ecosystem,knowledge of the factors that affect them are important in the management of forests.Currently,there are conflicting reports on the response of liana communities to disturbance,calling for more research in the area.The present study was carried out to investigate the response of liana diversity and structure to human disturbance within two major forests in the Penang National Park,Malaysia.The study also looked at the implication of the findings for conservation.Methods A total of 15 40×40-m^(2)(or 40-m×40-m)plots each were randomly located across a range of habitats in a primary forest and disturbed secondary forest.Trees with diameter at breast height≥10 cm were examined for lianas with diameter≥2 cm.Both lianas and trees were enumerated and compared between the two forests.Diversity and structural variables of lianas were compared between the two forests using the t-test analysis.Tree abundance was also compared between the two forests with t-test,while linear regression analysis was run to determine the effects of tree abundance on liana abundance.Important Findings A total of 46 liana species belonging to 27 genera and 15 families were identified in the study.Human disturbance significantly reduced liana species richness and species diversity in the secondary forest.Liana abundance remained the same in both forests whereas liana basal area was;7 times higher in the primary forest.Twiners and hook climbers were significantly more abundant in the primary and secondary forest,respectively.Large diameter lianas were more abundant in the primary forest compared with the secondary forest.The diameter distribution of most families in the primary forest followed the inverted J-shaped curve whereas only a few of the families in the secondary forest did so.Tree abundance was significantly higher in the primary forest.The abundance of lianas significantly depended on tree abundance in all the forests.The study has provided evidence of negative effects of human disturbance on liana diversity and structure that does not auger well for biodiversity in the forest.In view of the critical role of lianas in maintaining biodiversity in the forest ecosystem,lianas in the national park should be protected from further exploitation.

Liana community and functional trait analysis in tropical dry evergreen forest of India

Aim lianas are abundant and diverse throughout the world and consti-tute an important structural and functional component of tropical forests.This study aims to investigate liana diversity,abundance and their functional traits in Indian tropical dry evergreen forest(TDEF).Methods a total of ten 1-ha plots,one each in 10 Indian TDEF sites were demarcated.Each 1-ha plot was divided into one-hundred 10-×10-m quadrats to facilitate woody species inventory.all lianas≥1 cm diameter measured at 130 cm from the rooting point and all trees≥10-cm girth at breast height(gbh)were recorded from the study sites to analyze the patterns of liana diversity and abundance and also to compare the contribution of lianas to the total woody species richness,density and basal area.liana variables across the study sites were compared using one-way analysis of variance.The qualitative functional traits of inventoried lianas and trees were assessed on the field and referring to pertinent field manuals.Important Findingsa total of 9237 liana individuals(ranged from 408-1658 individu-als ha^(−1))representing 52 species,45 genera and 28 families were encountered from the 10 study sites.liana species richness ranged from 11-31 species ha^(−1) in 10 sites,which averaged 23.4(±5.7)species ha^(−1).The total basal area of lianas in the study sites was 7.3 m^(2)(0.20-1.76 m^(2) ha^(−1)).There was a significant variation in liana species richness,density and basal area across the studied sites.on the whole,lianas contributed 52%,49.3%and 4.1%to the total woody species(lianas and trees)richness,density and basal area,respectively.liana trait analysis revealed the majority(50%)of lianas belonged to brevi-deciduous type.stem twining was the chief climbing mechanism,exhibited by 21 species(52.6%of total abundance).more than half of the liana species(34 species;6925 individuals)had microphyllous leaves.Fleshy-fruited lianas mostly bearing berries and drupes constituted the major fruit type in the studied sites.Zoochory was the predominant dispersal mode observed in 63.4% of species.Considering the ecological and func-tional role of lianas in Indian TDEF,the need for conservation is emphasized.

Intercontinental comparison of liana community assemblages in tropical forests of Ghana and Malaysia

Aims Liana research has increased in the past two decades,yet there is still inadequate comparison of liana communities at a cross-con-tinental scale.We compared liana assemblages in tropical forest ecosystems of Ghana and Malaysia,thereby determining patterns and mechanisms that are common or unique to the regions.Methods Liana diversity,community structure and taxonomic composition were determined in 60 plots of 40×40 m2 in three forest types(primary,disturbed secondary,selectively logged)in each biogeo-graphic area.Two traits,climbing mechanisms and dispersal modes were determined for all species and individuals via direct field observation and with published literature.Data were analyzed at biogeographic(using combined forest data)and forest-type levels.Important Findings Both observed and rarefied-extrapolated species richness of lianas were significantly higher in Ghanaian forests compared to Malaysian forests.In most cases,species diversity indices(Shannon diversity index,Margalef,Fisher’s alpha)showed significantly higher liana diversity at Ghanaian forests at biogeographic and forest-type lev-els.Similarly,Ghanaian forests harbored significantly higher values of liana abundance and basal area than Malaysian forests at both biogeographic and forest-type levels.The taxonomic composition of lianas differed considerably between the two biogeographic areas at all levels,although similarity in composition increased at generic and family levels.Though above-ground biomass of lianas was simi-lar between the two biogeographic regions,variations occurred at forest-type level between the two regions.The two biogeographic areas showed some similarities in assemblages of liana climbing mechanisms.Although more species of lianas were adapted for animal dispersal than other dispersal modes in both countries,the majority of liana individuals in Ghana were wind dispersed whereas the majority of liana individuals in Malaysia were animal dispersed.We speculate that the differences in liana community assemblages between the two biogeographic areas are due to historical and evo-lutionary processes,as well as climatic variation between the two biogeographic regions.

Indirect facilitation by a liana might explain the dominance of a small tree in a temperate forest

Aims Lianas are expected to influence composition,structure and func-tioning of forest systems due to unequal distribution across the potential set of host plants.However,our understanding of mecha-nisms associated with preferences for specific hosts is still limited,and so is our ability to discern between endogenous and exogenous forces driving forest dynamics in the long run.In this paper,we eval-uated whether the dominant liana Hedera helix can indirectly con-tribute to the eventual dominance of the small multi-stemmed tree Corylus avellana in a remnant temperate forest in central Iberian Peninsula from comparatively reduced liana infestation on C.avel-lana relative to co-occurring woody species.Methods through principal component analysis and co-occurrence ana-lysis,we studied the distribution and spatial association between woody species and the liana H.helix.We analyzed the relationship between the number of species in a plot and the number of species infested by the liana to test the hypothesis that H.helix is a gen-eralist liana.through generalized linear mixed models,we tested the dynamic-multi-stemmed growth form of C.avellana as a plaus-ible life strategy to withstand,in the long run,the liana infestation.In particular,we tested(i)the relationship between stem size and the probability of H.helix infestation including all the tree species within plots and(ii)the relationship between stem size and mortal-ity as evidence of the stem turn over in the tree C.avellana.Important Findings Our results indicate that H.helix and C.avellana significantly co-occur in mature stands of this remnant temperate forest where pion-eer woody species are absent.Hedera helix severely infests all the woody species whenever stem size exceed≈25 cm perimeter and there is physical contact at the base of the stem.this implies that all the trees in the community are potential hosts for H.helix.Mixed models indicate that both,infestation by H.helix and stem mortality,are positively related to C.avellana stem perimeter.Reduced long-term infestation of the liana by means of a multi-stemmed growth form with high stem turnover in C.avellana might be an advantage with respect to unipodial tree species.thus,the liana-tree coexistence pattern may be interpreted as an indirect positive interaction that,contrary to previous findings,results here in species dominance instead of species coexistence.

几何之美

牛顿说:"几何学的简洁美却又正是几何学之所以完美的核心所在。"在数学的世界里,几何学作为一个重要分支,它以其独特的图形美感著称,从点、线、面到平面图形再到立体图形,这些丰富的元素是那么平凡,却又是那么奇妙,它们共同组合在一起,总能变幻出层出不穷的美丽。可以说,这个大干世界的每一样东西即便再复杂,其结构都离不开最基本的几何构成,把它们还原成最初的形态,也许会是简单的圆形、三角形、正方形、多边形……这份最原始的几何美也正是万物的魅力所在。