Woody Plant Populations Research Articles

Woody plant communities in different land management types and implications on mountain biodiversity conservation in central Ethiopia

The prominence of mountains as social-ecological systems and the need for sustainable mountain development have increasingly been recognized in global agendas and international conventions. This study aims to investigate woody plant diversity, composition, and population structure in two different land management types: lands managed by the Wanchi Ecotourism Association (WETA) and non-WETA members at the slopes of Wanchi Mountain. Trees and shrubs with diameter at breast height (DBH) ≥ 5 cm were recorded from 20 m by 20 m plots and those with DBH<5 cm were counted within sub-plots of 10 m by 10 m. Tree seedlings were recorded from five 3 m by 3 m sub-sub-plots. The quasi-Poisson generalized linear model with a log-link function was used to analyze the richness of woody species and their association with environmental variables. Non-metric multidimensional scaling with Bray-Curtis distance in two-dimensional space was employed for the woody species composition. Tree species population structure was analyzed using tree diameter distribution classes. The study identified 104 woody plants belonging to 82 genera and 52 families. Woody species richness in WETA-managed lands is significantly (P=0.009) greater than that of non-WETA-managed lands. The study found that woody species richness significantly declined with increasing anthropogenic disturbance (P<0.001) and slope (P<0.001) in both WETA and non-WETA-managed land. Woody species richness also showed negative associations with aspect. The tree species in both the land management types revealed nearly similar population structures. The study highlighted the importance of sustainable land management practices such as ecotourism in areas of significant natural endowments like that of the Wanchi Mountain. Such practices can guide more sustainable mountain biodiversity conservation while realizing appropriate local livelihood improvement strategies.

Niche of woody plant populations in Picea purpurea community in the upper Taohe River

The niche of plant populations is affected by the environment, species characteristics and anthropogenic disturbance. Picea purpurea, as a major constructive species in the northeastern Qinghai-Tibetan Plateau, had been severely damaged. Although the national project for the protection of natural forests has promoted the recovery of its community, its structure, survival status, development trend, and the factors affecting it are still unclear. We selected P. purpurea communities in Zecha, Dayugou and Yeliguan forest zones at different altitudes and disturbance levels. We analyzed niche characteristics of the woody plants and the relationship between niche and altitude, and disturbance. P. purpurea has absolute advantages as a constructive species, and its population dominance and niche width in the tree layer show a decreasing trend with decreasing altitude, there is niche overlap between all species pairs. In the shrub layer, the dominant species are mostly Caprifoliaceae and Rosaceae besides P. purpurea seedlings, the proportion of species pairs with niche overlap is YLG>ZC>DYG, and all appeared niche divergence and convergence species pairs. In addition, P. purpurea seedlings had niche overlap with most woody species, and this overlap index was the highest. The mean values of the niche overlap index between species in the tree and shrub layers were all YLG>DYG>ZC. The niche overlap index between species in the tree layer was greater than that in the shrub layer in the same forest zones, indicating that the tree layer is more stable than the shrub layer, providing evidence that niche overlap maintains community stability. Regression analyses showed that minimum temperature was the main factor affecting dominance, niche, niche overlap and shrub layer species richness of the P. purpurea population. Disturbance did not significantly affect dominance and niche of P. purpurea seedling populations, but promoted niche differentiation of shrub layer species. We conclude that the P. purpurea community is mainly influenced by altitude and anthropogenic disturbance. Altitude-induced climatic variation fundamentally determines the distinct community composition and population niche. Anthropogenic disturbance has altered habitat heterogeneity and enriched community structure. Furthermore, the P. purpurea populations show a trend towards expansion. Understanding the structure and niche characteristics of P. purpurea communities on different environmental gradients enriches our ideas for implementing vegetation restoration and sustainable forest management in subalpine zones in the context of climate change, and is conducive to improving the conservation capacity of this population or community type.

Effects of Landscape Heterogeneity and Disperser Movement on Seed Dispersal

The primacy of endozoochory for the maintenance and expansion of many woody plant populations is well known, but seed dispersal is not well understood for most species. This is especially true for rare species, where small population size and low fruit production can limit field- or observation-based experiments. Additionally, the effect of environmental heterogeneity on disperser movement is rarely investigated but has been shown to improve estimates of plant population spatial patterns and dynamics. We used simulation experiments to explore the effects of environmental heterogeneity and disperser movement on Lindera subcoriacea seed dispersal, a rare shrub from the southeastern United States with avian-dispersed seeds. Our experiments incorporated environmental heterogeneity and simulated disperser movement for five bird species, based on either landscape permeability or straight path rules. We anticipated that permeability-based movement would result in greater dispersal distances and seed dispersal effectiveness, which characterizes both quantity and quality. Generally, we did not find differences in seed dispersal between permeability and straight path experiments. However, we did find that permeability-based experiments had greater deposition into suitable habitat during flight (23 vs. 1%). These rare but longer distance depositions may be especially important for plants that are influenced by gap or interpopulation dynamics. We also found consistently greater dispersal into high quality habitats regardless of disperser species in permeability experiments, implying that incorporating species-specific assessments of landscape utilization (occupancy) could influence the effectiveness of seed dispersal. Our study suggests that including environmental heterogeneity in seed dispersal models can provide additional insights not provided by avian parameters (e.g., gut capacity, seed retention time, and flight speed) commonly used to inform dispersal models.

Подбор и оптимизация методов экстракции ДНК из листьев гледичии трехколючковой (Gleditsia triacanthos L.)

Abstract. Currently, molecular genetic methods using DNA markers are increasingly used in studies of polymorphism of various populations of woody and shrubby plants. The purpose of this work was the evaluation and selection of protocols for the isolation and purification of DNA from the leaves of Gleditsia triacanthos L. for further studies using DNA labeling. Methods. Four protocols were used to isolate DNA from the leaf blade of Gleditsia triacanthos L. Anionic detergent sodium dodecyl sulfate was used in three isolation protocols for cell lysis, potassium acetate was used for purification from polysaccharides and proteins. In the fourth protocol, a cationic surfactant cetyltrimethyl ammonium bromide was used for cell lysis, the extract was purified with a mixture of chloroform-isoamyl alcohol (24 : 1). Precipitation of the isolated DNA was carried out with isopropanol. The quality of the isolated DNA was evaluated by spectrophotometry, horizontal electrophoresis and Real-time PCR with two types of primers. Results. Optimal conditions for DNA extraction from samples of Gleditsia triacanthos L. containing a large number of metabolites affecting the quality of the isolated extract were selected. By electrophoresis, it was found that both the isolation protocol with sodium dodecyl sulfate and the isolation protocol with cetyltrimethyl ammonium bromide make it possible to obtain a sufficient amount of DNA. The most purified DNA was obtained by the third protocol using sodium dodecyl sulfate and dithiotreitol and by the fourth protocol using cetyltrimethylammonium bromide. The results of PCR of the obtained samples with ITS and psbI-psbK primers indicate that a sufficient amount of product has been obtained and the reproducibility of ISSR markers. The scientific novelty of the work consists in choosing the optimal method of DNA extraction from the leaves of Gleditsia triacanthos L., which is a complex object containing a large number of potential PCR inhibitors. The protocol with sodium dodecyl sulfate and dithiotreitol made it possible to obtain DNA in the right amount and of acceptable quality.

Географические особенности возобновления Pinus sibirica Du Tour

One of the main problems of forest ecology is to identify the patterns of the dynamics of natural populations of woody plants at the stage of their renewal, which programs the entire subsequent structure and development of plant ecosystems. The process of reforestation is determined by both the dynamics of seed production and the peculiarities of the seed distribution of forest-forming tree species. The renewal of five-needled pines of the Cembrae subsection with wingless seeds is due to their close trophic relationships with birds of the genus Nucifraga sp., which spread seeds, creating soil forage stocks. The purpose of this study is to reveal geographical features of the relationship between seed production and renewal of Siberian stone pine (Pinus sibirica Du Tour) with the intermediary participation of the thin-billed nutcracker (Nucifraga caryocatactes macrorhynchos Brehm C.L.). The research was carried out in 3 geographical regions of Pinus sibirica forests: in the forests of the Aldan Highlands in Southern Yakutia (59º40´ N., 125º24´ E.), the Northern Urals in the area of the Denezhkin Kamen mountain (60º25´ N., 59º32´ E.), and the Khamar-Daban Mountain range in the South-Eastern Baikal region (51º32´ N., 103º32´ E.). It is shown that each region of the Pinus sibirica growth differs in the dynamics of both seed production and renewal. It was found that the abundance of Pinus sibirica seedlings in the forests of the Aldan Highlands is positively associated (R2 = 0.46) with the yield of cones the previous year. The number of seedlings in the Northern Urals and Khamar-Daban is negatively related to the yield of cones of last year but is positively (R2 = 0.48–0.49) associated with the yield of cones of the year before last. We believe that seedlings in any case appear from the seeds of last year's yield. But the visible connection is due to the activity of the nutcracker. As a result of the stationary studies conducted in the Northern Urals, we identified a constant close (R2 = 0.81) positive relationship between the number of Pinus sibirica seedlings and the number of nutcrackers during the period of seed storage and dispersal in August-September of the previous year. It is assumed that the nature of the dynamics of seed production in the region affects the change in the number of nutcrackers during the seed harvesting period, which in turn determines the abundance of Pinus sibirica seedlings next year. This determines the revealed differences in the dynamics of Pinus sibirica renewal and its dependence on the yields of tree cones in the regions under consideration. For citation: Tantsyrev N.V., Sannikov S.N., Usoltsev V.А. Geographical Features of Pinus sibirica Du Tour Renewal. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 6, pp. 44–56. (In Russ.). https://doi.org/10.37482/0536-1036-2023-6-44-56

Fluctuating Asymmetry as a Measure of Stress in Natural Populations of Woody Plants: Influence of Ecological and Geographical Factors on Developmental Stability

Fluctuating asymmetry is a sensitive indicator of favorable conditions during the period of individual development. The influence of climatic factors, biotopic conditions, latitude, altitude, and age of plants from the natural populations of the silver birch Betula pendula Roth was analyzed. The material consisted of 13,000 leaves of the silver birch from 11 regions of north-eastern Siberia. The influence of 23 climatic factors and six integrated coefficients characterizing the general suitability of the climate, as well as summer, winter, spring, and autumn was analyzed. The developmental stability of woody plants and, consequently, the level of the FA of the lamina in natural biotopes can vary in a wide range. We found that climatic factors, mainly conditions in the warm season, have a significant impact. We also noted the influence of the age, biotope, and light conditions. For Betula pendula, an increase in FA was registered on the ecological periphery of its range, i.e., on the edge of the forest belt in the north and in the mountains. The data obtained demonstrate the high influence of natural stress-inducing factors on development stability in plants.

Regeneration of Pinus sibirica Du Tour as a result of trophic relationships with the thin-billed nutcracker (Nucifraga caryocatactes macrorhynchos Brehm C L)

Identifying the patterns of dynamics of natural populations of woody plants at the stage of their renewal is one of the main problems of forest ecology. The reforestation process is determined by both the dynamics of seed production and the specificity of seed dispersal of forest tree species. The five-needled pine renewal the Cembrae subsection with wingless seeds depends on birds of the genus Nucifraga sp., which store and spread their seeds. The aim of this study is to determine the relationship between seed production and regeneration of Pinus sibirica Du Tour using the thin-billed nutcracker (Nucifraga caryocatactes macrorhynchos Brehm C. L.) as a mediator. Long-term studies of these relationships have been carried out in the Siberian pine forests of the North Ural Mountains. As a result, a paradoxical conclusion is made that the number of Nucifraga birds during the period of storing and spreading of seeds in the previous year is a key factor in the abundance of Pinus sibirica seedlings. In turn, the number of seeds, both from the previous year and the current year, affects the number of Nucifraga birds.

Rear‐edge daylily populations show legacies of habitat fragmentation due to the Holocene climate warming

AbstractAimsQuaternary climate changes dramatically affected species' distributions and thus impacted genetic diversity patterns, particularly for rear‐edge populations. Empirical studies have shown the southernmost (rear‐edge), fragmented populations of Japanese woody plants can harbour high genetic diversity owing to their origin in southern glacial refugia. The effect of Holocene climate warming on rear‐edge populations has, however, rarely been demonstrated. We assessed whether the genetic structure of populations of temperate plants in Japan can be interpreted to show legacies of both icy (Last Glacial Maximum, LGM) and warm (Holocene) climates.LocationJapanese Archipelago.TaxonHemerocallis middendorffii (Asphodelaceae).MethodsPopulation genetic profiles of 737 individuals from 41 populations were analysed to examine population structure and past population demography, using 12 EST‐SSR markers. Present and past suitable habitat areas during the LGM and the Holocene climatic optimum were estimated by ecological niche modelling (ENM). Reconstructed palaeodistribution was combined with population genetics to statistically predict population demographics in relation to past climate changes.ResultsGenetic analysis of the 41 populations revealed 6 regional population groups. Four groups widely dominating the northern–central ranges harboured high genetic diversity, whereas genetic divergence within the groups was low. In contrast, the two groups at the southwestern edge were geographically and genetically isolated, and they showed the lowest genetic diversity. The estimated palaeodistributions showed a decrease in the suitable range during the Holocene in comparison with that at the LGM, and only habitat suitability in the Holocene was able to predict the genetic diversity across the range.Main conclusionsPopulations at the centre of the current distribution harbour high genetic diversity because they remained stable during both cold and warm periods. However, habitat fragmentation and population decline in relation to climate warming during the Holocene resulted in genetic isolation and impoverishment of the rear‐edge populations.

Woody plant decline in the Sahel of western Niger (1996–2017):is it driven by climate or land use changes?

Although a recovery of woody vegetation has been observed throughout the Sahel, western Niger has not followed the overall satellite-derived greening trend. While satellite imagery can be used to study overall patterns and trends, only field observations can provide insights in the dynamics of woody plant populations. Here we used field data from 29 sites in the Dantiandou district in Niger to study woody species composition, plant density, crown cover, basal area, foliage and wood mass from 1996 to 2017. All sites show a decrease in woody plant parameters with a faster decrease in rangeland than in agricultural land. Most of the decrease is due to the loss of shrubs, while trees do not change significantly. When field observations were scaled up to the district level using land use maps, shrub density decreased from 342 to 155 ha−1 in agricultural land, and from 1567 to 250 ha−1 in rangeland. Trends in annual rainfall and soil moisture during the study period were not significant and cannot explain the decrease of woody vegetation. Instead, the expansion of cropped areas, shortened crop-fallow cycles and increasing pressure on wood resources to satisfy demand for fuel and construction materials may have contributed to the decline.

洮河自然保护区大峪沟林区紫果云杉群落木本植物种群生态位特征

PDF HTML阅读 XML下载 导出引用 引用提醒 洮河自然保护区大峪沟林区紫果云杉群落木本植物种群生态位特征 DOI: 10.5846/stxb202102070395 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 甘肃省林业科技创新项目（KJCX201909，KJCX202001）；甘肃省林业科技项目（2015KJ051）；林业科技推广项目（2020ZYTG16） Niche of woody plant populations of Picea purpurea community in Dayugou forest area, Taohe Nature Reserve, Gansu Province Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于群落调查数据，以样地代表多种资源的综合状态，物种重要值作为生态位的计测指标，利用Levins和Shannon生态位宽度，Schoener生态位相似和Pianka生态位重叠对洮河自然保护区大峪沟林区的紫果云杉群落木本植物种群生态位进行定量研究。结果表明：紫果云杉群落乔木层共有树种8种，隶属于4科6属，紫果云杉占绝对优势，岷江冷杉为次优势种；灌木层共有植物50种，隶属于16科25属，忍冬科的蓝靛果、葱皮忍冬和唐古特忍冬等以及蔷薇科的峨眉蔷薇和银露梅等构成了灌木层的主体，紫果云杉幼苗优势不明显，但生态位宽度最大。本研究表明，生态位宽度受物种生态特性及其分布和生境共同影响，重要值大的物种生态位宽度一般较大，生态位宽度大的物种之间生态位相似性和重叠性一般较大，并与其它物种重叠的概率高、重叠程度大，生态位宽度小的物种集中出现时也会出现较大的生态位重叠，同科或同属的物种间常有较大生态位相似和重叠。生态位宽度反映着种群的扩散潜力，生态位相似反映着群落的稳定性，生态位重叠反映着物种间存在或潜在的竞争程度。紫果云杉在乔、灌木层均有最大的生态位宽度，生态适应性最强，群落结构稳定，具有进一步扩散的可能。 Abstract:Based on the plant community investigation data, and with plots representing the comprehensive status of multiple resources, and species importance values as measurement indicators of niche, the niche characteristics of woody plant species in the Picea Purpurea Community in Dayugou forest area of the Taohe Nature Reserve were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarities and Pianka niche overlap. The results showed that there were 8 tree species in the tree layer of the picea purpurea community, belonging to 4 families and 6 genera, among which the picea purpurea was the absolute dominant species, and the Abies faxoniana was the subdominant species; the shrub layer had a total of 50 species of plants belonging to 16 families and 25 genera, among which Lonicera caerulea, Lonicera ferdinandii and Lonicera tangutica of the Caprifoliaceae and Rosa omeiensis and Potentilla glabra of the Rosaceae are the dominant species of the shrub layer, and the picea purpurea seedlings did not have obvious advantages but they had the widest niche breadth. This study indicated that the niche breadth was affected by the ecological characteristics of species as well as their distribution and habitat. The species with large important values generally had larger niche breadth, and the species with large niche breadth generally had the larger niche similarity and overlap, and had higher probability and degree of overlap with other species; there were also large niche overlaps when species with small niche breadth were concentrated, and the species of the same family or genus often had larger niche similarities and overlaps. Niche breadth reflected the population dispersal potential, the niche similarity reflected the stability of a community, and the niche overlap reflected the degree of the existing or potential competition among species. Picea Purpurea had the widest niche breadth in both the tree layers and shrub layers, the strongest ecological adaptability, the stable community structure, and thus the possibility of further dispersal. 参考文献 相似文献 引证文献

Assessment of woody plant species composition in secondary deciduous forests of Odisha, India

Plant species composition according to their functional types, distribution pattern are crucial for biodiversity conservation in tropical deciduous forest. The study assessed the woody plant species diversity, stand structure and population density in the secondary deciduous forest of Chandaka wildlife sanctuary, Odisha, India. A total of 70 species belonging to 63 genera and families were documented in this study.The stem density was found to be 1080 stems/ha with reverse J-shaped population structure indicating good regeneration potential of the forests. Shannon diversity Index varied from 0 to 2.31 whereas Simpson's index varied from 0 to 0.85. The correlation study between Importance Value Index and basal area were significant (p=40.63). The present study would be helpful for conservation and management of biodiversity in secondary dry deciduous forests of Chandaka Wildlife Sanctury in particular and tropical dry forests in general.

Woody Plant Species Composition, Population Structure and Carbon Sequestration Potential of the A. senegal (L.) Willd Woodland Along a Distance Gradient in North-Western Tigray, Ethiopia

In Ethiopia, dry land vegetation including the fairly intact lowland and western escarpment woodlands occupy the largest vegetation resource of the country. These forests play a central role in environmental regulation and socio-economic assets, yet they received less scientific attention than the moist forests. This study evaluated the woody plant species composition, population structure and carbon sequestration potential of the A. senegal woodland across three distance gradients from the settlements. A total of 45 sample quadrants were laid along a systematically established nine parallel transect lines to collect vegetation and soil data across distance gradients from settlement. Mature tree dry biomass with DBH＞2.5 cm was estimated using allometric equations. A total of 41 woody plant species that belong to 20 families were recorded and A. senegal was the dominant species with 56.4 IVI value. Woody plant species diversity, density and richness were significantly higher in the distant plots compared to the nearest plots to settlement (p＜0.05). The cumulative DBH class distribution of all individuals had showed an interrupted inverted J-shape population pattern. There were 19 species without seedlings, 15 species without saplings and 14 species without both seedlings and saplings. A significant above ground carbon (5.3 to 12.7 ton ha-1), root carbon (1.6 to 3.6 ton ha-1), soil organic carbon (35.6 to 44.5 ton ha-1), total carbon stock (42.5 to 60.7 ton ha-1) and total carbon dioxide equivalent (157.7 to 222.8 ton ha-1) was observed consistently with an increasing of distance from settlement (p＜0.05). Distance from settlement had significant and positive correlation with species diversity and carbon stock at 0.64** and 0.78**. Disturbance intensity may directly influence the variation of species composition, richness and density along the A. senegal woodland. The sustainability of the A. senegal woodland needs urgent protection, conservation and restoration.

Influence of Soil Type and Rocky Outcrops on the Species Distribution in a Woody Plant Community at Brazilian Semiarid

Cerrado is a biome that holds many phytophysiognomies, influenced by the edaphic factors, where the type of substrate is strongly related to the established vegetation. This study aims to verify on how soil physicochemical properties, as well as the presence of rocky outcrops, influence the species distribution of woody plants in a Cerrado fragment located in deep soils and tabular relief at Serra do Boqueir&amp;atilde;o (289 m elev.) Lavras da Mangabeira municipality (6&amp;ordm;72&amp;prime;24&amp;Prime; S; 38&amp;ordm;97&amp;prime;73&amp;Prime; W), Northeastern Brazil. Every individual with a DNS &amp;ge; 3 cm in 12 sampling units with an area of 12 &amp;times; 30 m (0.432 ha) was sampled. PAST v. 3.23 software was used in the Main Component analyses. The physical and chemical analyses of the soil were made with samples collected at 0-20 cm and 20-40 cm depths. Differences in diversity, hierarchy and dominance volume of woody plant populations were found between sites with or without the presence of rocky outcrops. The soil has a tendency for water erosion and the aluminum saturation reached values of concentration of 7.9 cmolc dm-3, with a pH value between 4.1-4.2 in rocky environments. The obtained results suggest that Q. parviflora and A. occidentale probably have some kind of resistance to the toxicity of aluminum in soil with a pH value below 5.0.

Impact of Exclosure on Species Diversity, Population Structure and Regeneration Status of Woody Plants in Lowland Northern Tigray, Ethiopia

Aim: This study was conducted to assessing woody plant composition, population structure and regeneration status in lowland exclosure (EX) of Northern Ethiopia.&#x0D; Study Design: Investigation of parameters was undertaken from 71 plots with size of 20 m x 10 m laid systematically along transect lines for vegetation data. These 200 m2 plots were used for assessment of trees with DBH &gt;5 cm. Small quadrats of 4 m*4 m (16 m2) nested within the bigger plots was laid at the four corners and center of each plots. These were used for measuring seedling and sapling individuals. To analyze species diversity, population structure and regeneration status of woody plants were by computing abundance, density, basal area, Importance value index (IVI) and using Shannon-Weiner diversity and evenness indices.&#x0D; Results: According to vegetation survey result, a total of 23, 17 and 26 woody species were recorded, at Kara, Erba and Shektekli exclosures (EXs), respectively. While 8, 7 and 5 species of woody plant were in open grazing land (OGL). The total mean densities of all woody plants were found to be 1530, 1480 and 2999 individual’s ha-1 at Kara, Erba and Shektekli in EXs.&#x0D; Conclusion: The study suggested that the regional government have to considering EXs as useful for restoration or rehabitation strategy in the region, the vegetation in all the EXs in the study sites have a higher species composition, diversity, density, increment of basal area and regeneration woody plants than OGL, as a result of management differences in EXs. However, there are also variation on species composition, diversity, density increment of basal area and regeneration woody plants among exclosures having similar age and altitude for instance the species recorded in Erba site is lower than with other of EXs, This could be due to among local site characteristic variation and high grazing happen before Ex establishment exists. Therefore, we need to apply soil and water conservation, enrichment planting with indigenous tree species and strengthen local management institution in effectively protect the exclosure.

A study on vegetation community and plant species diversity of Yeli Island, Zhuhai, China

The vegetation of Yeli Island is of great importance to biological and cultural diversity and to the ecosystem services of Zhuhai. To understand the vegetation ecology, vegetation development process and vegetation structure of Yeli Island, a detailed vegetation investigation was conducted on the Yeli Island through line survey and sampling survey methods. Analysis of woody plant population structure and plant species diversity were conducted. Vegetation on this island was relatively simple since it had been once destroyed. It was mainly covered by artificial Acacia confusa. The upper layer was filled with Acacia confusa and the lower was filled with small trees, shrubs and a few herbs. The dominant population of Acacia confusa was gradually degraded, and a series of newer secondary communities had been formed in the lower layer. The index of biodiversity was low. The vegetation quality was not high. Positive measures should be taken to promote the recovery of this community.

Внутривидовое генетическое разнообразие популяций двух видов древесных растений Пермского края

Researched 3 Scots pine populations (Pinus sylvestris L., Pinaceae) and 3 populations of western species of Siberian larch (Larix sibirica Ledeb., Pinaceae) in Perm krai for genetic diversity within species detecting. 114 ISSR–PCR P. sylvestris markers and 116 ISSR–PCR L. sibirica markers were amplified. The rate of polymorphic loci expected heterozygosity and number of rare ISSR–PCR markers were identified. Researched species are characterized by high genetic diversity. The rate of polymorphic loci is higher in P. sylvestris; expected heterozygosity and the number of effective alleles is higher in L. sibirica. Each species has populations with high and low genetic diversity parameters. The rare alleles were identified in every of 6 researched populations, but the number ranges from 6 to 13 in P. sylvestris populations and from 3 to 10 in L. sibirica populations. Genetic structure of researched populations analysis show that the interpopulation component of genetic diversity accounts for 30.28% in P. sylvestris and 30.92% in L. sibirica; most of the genetic diversity of P. sylvestris (69, 72%) and L. sibirica (69.08%) is concentrated within populations. Generic markers were found for the genus Pinus and Larix, and species markers for P. sylvestris and L. sibirica. Identification polymorphic markers or their combinations typical for the studied populations of two studied species. The molecular genetic formulas and barcodes of the studied populations are composed. Data on the intraspecific genetic diversity of populations of woody plants of the Perm krai will allow to recommend measures of their conservation, as well as to carry out molecular genetic identification of both natural populations and wood from these populations, which is important for determining the legality of its harvesting.

Expanding networks of field hedges in densely populated landscapes in the Sahel

Changing woody plant density across agricultural landscapes of the Sudano-Sahelian region is a debated issue. This paper reports the results of an investigation on the contribution of field hedges to overall woody plant density. Hedges separating individual cropped parcels were studied within village agropastoral territories in the Dantiandou district in western Niger. In 1992, field hedges were mapped over the study area using aerial photography and in 2016, using high resolution Google Earth imagery. In 1992, field hedge length was equal to 1006 km within 435 km2 of croplands, equivalent to 2.3 km km−2. In 2016, 17.5% of these hedges had disappeared, but 1591 km of new hedges were observed resulting in an increased density of hedges to 5.6 km km−2. In 24 years, hedges had increased at a mean annual rate of 3.7% likely associated with the splitting of crop fields by inheritance.The composition and productivity of hedges were also monitored in 1996, 2010 and 2015. All trees (maximum height ≥ 4 m), shrubs (<4 m) and tussock perennial grasses were recorded within twelve field hedge samples of 200 m each. Field measurements were used to estimate basal area, crown area, foliage mass and wood mass of each woody plant within the sampled hedges. No significant trends were found between 1996 and 2015 in woody plant density, basal area, crown cover, wood and foliage masses across all monitored hedges. However, overall means hide a slight decrease in tree contributions, while shrub contributions first increased and then decreased. They also mask contradictory trends among sites most likely related to different rates of shrub coppicing and tree cutting. The woody species composition of the hedges is poor with an increase of Combretum glutinosum to the detriment of Guiera senegalensis over the study period.Multiplying the hedge sample statistics by the changing lengths of field hedges in the study area provides estimates of the contribution of the hedge woody plants to the woody plant population at a landscape scale. Between 1992 and 2016, field hedges contributed to increases of woody plant density by 3.9%, basal areas by 5.4%, crown cover by 2.7%, leading to 6.1% annual increase in foliage mass and 8.8% increase in wood mass.

Rabbits and livestock grazing alter the structure and composition of mid-storey plants in a wooded dryland

Woody plants are critical for supporting wildlife and maintaining ecosystem structure and function in drylands. Grazing has the potential to alter woody plant community structure by affecting the size and survival of shrubs and saplings. We assessed the role of recent and historic grazing by livestock, and recent grazing by kangaroos and rabbits, on woody plant structure and composition. We measured the density and species occurrence of saplings and shrubs within three plant communities across 0.5 M km2 of eastern Australia and used generalised linear mixed models to examine how grazing, soil texture and the basal area of mature trees altered the structure and composition of mid-storey woody plants. Due to co-evolution, we expected a stronger negative effect of grazing on shrub and sapling density and species occurrence by introduced herbivores than native herbivores and that shorter individuals would be more susceptible to recent grazing activity. We found that the density and occurrence of shrubs and saplings generally responded more negatively to introduced herbivores irrespective of their height. Sapling density was strongly reduced by recent rabbit and livestock grazing but increased in density at sites with greater kangaroo and historic livestock grazing. Recent livestock grazing also reduced the occurrence of sapling species. There were no strong effects of any grazing on shrub density, but rabbit grazing strongly reduced shrub species occurrence, with few strong responses among individual species. Our data provide strong evidence that recent grazing by livestock and rabbits can reduce sapling density and alter woody plant occurrence. This has the potential to induce long-term changes in ecosystem structure by limiting shrub and sapling establishment which could lead to aging and contracting woody plant populations.

Niche of main woody plant populations of Pterocarya stenoptera community in riparian zone of Lijiang River, China.

To understand the niche characteristics of main woody species in Pterocarya stenoptera community, we investigated P. stenoptera communities in riparian zone of Lijiang River, China. The niche characteristics of main species in tree layers and shrub layers were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarities and Pianka niche overlap. The results showed that P. stenoptera in the tree layer, and Ficus abelii and Morus alba in the shrub layer had higher niche breadth than other species. The species with larger importance values generally had larger niche breadth, but the rank orders of which were not exactly the same. The niche similarity of main populations in the tree layer was generally smaller than that in the shrub layer. The mean value of niche similarity of main populations in the tree layer and shrub layer was 0.151 and 0.236, respectively. There was a low degree of niche similarity among species within the community, indicating that they had a low similarity in resource use. The niche overlap of main populations in the tree layer was generally smaller than that in the shrub layer, with the mean value of niche overlap of main populations in the tree layer and shrub layer being 0.217 and 0.273, respectively. The niche overlap between the main species in the community was relatively lower. There was no significant correlation between niche breadth and niche similarity. The species with larger niche breadth often had more opportunities to overlap with other species. However, their overlap value was not necessarily larger. Larger niche similarity was often associated with higher degrees of niche overlap. The P. stenoptera community in riparian zone of Lijiang River was the climax community, the relationship among species was relatively stable, the population regeneration was very slow, and the development trend of this community was declining in the future.

English

Ethiopia is one of the biodiversity reach areas in the world. A study was conducted at Amoro Forest to determine the woody species composition, vegetation and population structure. Vegetation data were collected from 36 plots (900 m2) systematically laid along transects. A hierarchical cluster analysis with R software was used to identify plant communities. Structural analysis of the forest was performed based on frequency, density, DBH, basal area and importance value indices (IVI) of woody species. A total of 57 woody species belonging to 38 families were encountered, consisting of 19 tree (33.33%), 31 (54.38%) shrubs, and 7(4.37%) liana species. The vegetation of the forest was classified into four plant communities namely, Calpurnia aurea-Vernonia myriantha, Vernonia myriantha-Euphorbia abyssinica, Laggera tomentosa-Solanecio gigas, Allophyllus abyssinicus-Bersama abyssinica based on cluster analysis. The total basal area and density of woody plants were 18.5 m2/h and 2860.49 stems/h respectively. The DBH distribution showed a reverse “J” shaped curve, meaning that there is active regeneration and recruitment in the forest. Four representative woody plant population structures were identified, that is, inverted J, Gauss I, Gauss II and J- shaped patterns. There is high anthropogenic effect and high dependence of the local community in Amoro Forest so that forest conservation and restoration measures should be required. Key words: Ethiopia, Amoro Forest, vegetation communities, anthropogenic activities and population structure.