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1.
For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a transect line. For assessing seedlings and saplings,two 2 × 10 m sub quadrats were set upon opposite sides of each main quadrat. Data on species diversity, abundance,structure, basal area, density, frequency and regeneration status were collected and analyzed using standard procedures and programs. Of 58 woody plant species identified,69 % were trees, 16 % were shrubs, 12 % were tree/shrubs and 4 % were climbers. Fabaceae was the most speciesrich family comprising 17 species. The Shannon–Weiner diversity index was 2.73, and evenness was 0.67. The population structure in the cumulative diameter class frequency distribution revealed an interrupted and inverted J-shape with a very high decrease in higher diameter class.Acacia lahai(49 %) was the most important woody species with the highest importance value index. To maintain balanced structure, enhanced regeneration and protecting the forest from selective cutting are recommended. 相似文献
2.
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. 相似文献
3.
埃塞俄比亚东南部Dello Menna森林植被的植物区系和结构分析(英文) 总被引：2，自引：0，他引：2
描述了埃塞俄比亚东南部Dello Menna森林植被的植物区系组成和植被结构。鉴定和描述了50个20m×20m的样方的植物群落类型、物种多样性、丰富度和均匀性,分析了已鉴定植物群落类型与环境因子的相关性,还描述了木本植物种群结构。每个样方内,均记录木本植物的物种、丰富度、高度和胸径以及海拔、坡度。利用PC-ORD软件对植被进行分类。用Sorensen相似性系数探测群落之间的差异性。计算Shannon-Wiener多样性指数、物种丰富度、Shannon均匀性来描述各种植物群落的物种多样性。共记录了53个科的171个维管植物种。豆科植物是主要的优势植物科系,包括13个属26种(1 5%),其次依次是菊科、唇形科和槭树科,各包括8个物种(4.6%)。根据植物分类结果,识别并描述了3个植物群落(Dalbergia microphylla群落、Grewia bicolar-Acaciabrevispica群落、Combretum molle-Combretum collinum群落)。植物区系之间的物种丰富度、多样性和均匀性存在差异。物种丰富度和多样性随海拔变化呈现出贝尔型分布。群落间植物随海拔梯度有一定的变化,表明海拔是决定植物群落分布的重要因素之一。Dalbergia microphylla群落物种丰富度和多样性均最高。优势种群落结构呈现出各种模型。植被可持续利用是今后的研究方向。 相似文献
4.
对水胡黄天然次生林的植物物种组成及多样性进行分析的结果表明:两个地点所有物种的共有度为0.681;通过调查,标准地中共记录植物物种60种,分别隶属于39科、54属,其中乔木16种、灌木14种(藤本2种)、草本30种;茂林河林场木本植物的物种多样性明显高于建设营林所,其丰富度指数为30,Shannon-Weiner指数达到2.602,均匀度指数为0.914,优势度指数为0.116;而且两个地点的乔木层的多样性指数明显高于灌木层的多样性指数。 相似文献
5.
《林业研究》2021,(5)
Dry afromontane forests are among the most poorly managed and endangered ecosystems.Therefore,we assessed the composition,diversity,and conservation status of woody plant species of the Debre Libanos church forests and surrounding forest lands in Oromiya Regional National State,central Ethiopia in 62 nested circular sample plots spaced 200 m apart along two transect lines.Large circular plots 314 m~2 were used to sample trees with DBH of at least 10 cm,and subplots of 28.26 m~2 were laid in each main plot were used to assess saplings and shrubs;a small subplot of 3.14 m~2 was used to assess seedlings.In total,70 woody plant species belonging to 62 genera and 43 families were recorded.Of these,59,28 and 32 were in the church,government and private forest types,respectively.The most dominant families were Fabaceae and Verbenaceae,each represented by five species.In the forests considered,trees accounted for 61%,and shrubs with diameter at breast height(DBH) of 1-10 cm accounted for ca.33%.Among growth forms of woody species,shrubs and seedlings,followed by trees constituted much of the density of woody species in all the three ownership types of forests.The church forest had the most species(59) and highest Shannon(3.12) and Simpson(0.92) species diversity indices,and the government and private forests had a nearly similar total number of species and Shannon and Simpson species diversity indices.Most of the species with higher importance value indices(IVI) were indigenous in origin within the church forest(Juniperus procera=82),government forest(J.procera=66) and private forest(Acacia abyssinica=84).The composition,diversity,and population structure of woody species in the church forest were significantly higher than in the other forest lands.However,interventions of the government and private sectors to conserve forest systems in the areas,particularly the government-owned forest and specific species such as Olea europaea need active enrichment plantings due to their limited natural regeneration.Without improved management interventions,livelihood income diversification and ecosystem services obtained from the forest will not be sustainable. 相似文献
6.
Species diversity,population structure and regeneration of woody species in fallows and mature stands of tropical woodlands of southeast Angola 总被引：1，自引：0，他引：1
Francisco M. P. Gonçalves Rasmus Revermann Manuel J. Cachissapa Amândio L. Gomes Marcos P. M. Aidar 《林业研究》2018,29(6):1569-1579
This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population structure of the most harvested woody species by calculating size class distribution and evaluated their regeneration potential based on the density of saplings. The vegetation was surveyed in 20 plots of 20 × 50 m(1000 m2). In each plot, we measured the diameter at breast height(DBH) of all woody species with DBH ≥ 5 cm. The saplings were counted, identified and recorded; 718 individuals, corresponding to 34 species in 32 genera and 15 families were recorded. The size class distribution of target woody species showed three different patterns in fallows and mature woodlands. In general,most of the smaller diameter classes had more individuals than the larger ones did, showing that the regeneration may take place. However, in some diameter classes, the absence of larger stems indicated selective logging of larger trees. Few saplings were recorded in the fallows or mature woodlands; fire frequency and intensity is probably the main obstacle for seed germination and seedling survival rates in the studied area. 相似文献
7.
广东象头山吊皮锥种群及其群落结构研究 总被引：2，自引：0，他引：2
吊皮锥（Castanopsis kawakamiiHayata）为我国特有的第三纪孑遗植物,稀有种。文章应用样方调查法分析了惠州市象头山吊皮锥种群结构及其所在群落的物种多样性。在1800m。的样方内,共记录了维管植物172种,隶属73科126属;胸径≥2．5cm的乔灌木层物种丰富度指数为8．39,Shannon—Wiener多样性指数为3．06,Pielou均匀度指数为0．80。该群落以樟科、壳斗科和山茶科为优势科,樟科植物种类最丰富,具有最高的重要值。重要值最高的树种为黄果厚壳桂（Cryptocarya concinna）,其次为荷木（Schimasuperba）、唐竹（Sinobambusatootsik）和硬斗稠（Lithocarpus hancei）。比较分析了黄果厚壳桂、阿丁枫（Altingia chinensis）、鼠刺（Iteachinensis）、硬斗稠、荷木、黄杞（Engelhardtiaroxburghiana）、马尾松（Pinusmassoniana）、吊皮锥的种群结构。结果表明,黄果厚壳桂和鼠刺的种群较大,但以Ⅰ～Ⅲ级苗和幼树为主,缺乏大径级林冠层大树;荷木种群也较大,但缺乏幼苗;吊皮锥和硬斗稠为稳定型种群;阿丁枫、马尾松和黄杞的种群较小,有少量林冠层大树,但缺乏幼苗,林下自然更新不良,为衰退种群。建议加强吊皮锥的种群动态监测和迁地保护研究,促进吊皮锥资源的保护和利用。 相似文献
8.
采用典型样方调查法,对云南九龙山自然保护区内的水青冈群落生物多样性及群落特征进行研究,共设置7个30 m×30 m的样方,从群落的物种组成、重要值、物种多样性、种群年龄结构等方面进行分析。结果表明:云南九龙山水青冈群落中共有维管束植物81种,隶属48科71属,其中蔷薇科为优势科;物种丰富度、多样性、均匀度和优势度在所有群落中均表现为草本层>灌木层>乔木层;在水青冈种群年龄结构中,Ⅳ级和V级所占比例为21.4%、78.6%,未发现幼苗、幼树分布,表明种群自然更新不良,表现为衰退型。提出减少人为干扰因素,促进群落自然更新,建立种群动态数据库,在保持群落物种多样性的同时注重维持群落稳定性等保护建议。 相似文献
9.
南京紫金山春季蛾类多样性研究 总被引：5，自引：1，他引：4
采用灯诱的方法对紫金山4种不同植被类型鳞翅目蛾类资源进行了调查.共收集蛾类1182只,隶属于9总科、21科、155属176种.应用Shannon-Wiener多样性指数、均匀度、优势度、相似性系数等分析了紫金山不同植被类型蛾类的多样性.结果表明:紫金山阔叶林蛾类多样性较高,种类较丰富;针阔混交林、针叶林、竹林等植物群落正处于演替的某个中间阶段.蛾类多样性指数不受均匀度影响.植物群落及生态环境的差异是导致蛾类群落结构差别的主要因素.蛾类可作为环境变化的指示物种. 相似文献
10.
We investigated the composition of tropical dry forest woody species at adult, sapling, and seedling stages, in terms of plant diversity, distribution, and importance value index (IVI), and identified the dominant and ubiquitous species in the five study sites having variable edaphic properties. Species varied markedly in the composition and IVI at different sites. The semi-evergreen species, Shorea robusta, was dominant at the wettest site at all the three growth stages; at the driest site, highly deciduous species Lannea coromandelica was the dominant adult species and Nyctanthis arbortristis the dominant sapling and seedling species. Soil moisture content (SMC) altered the distribution of about 8% of the adult species. ANOVA indicated significant site-wise differences in the Shannon-Wiener index, Whittaker’s evenness, Margalef’s species richness, and β-diversity for the woody species at all the three stages. The Shannon-Wiener index, Whittaker’s evenness, Margalef’s species richness, and β-diversity were greater in seedlings as compared to adult and saplings of tree species. These variations in species composition and distribution are evidently on account of different levels of SMC as well as habitat heterogeneity as indicated by β-diversity which was independent of SMC. 相似文献
11.
12.
《林业研究》2021,32(5)
Miombo woodlands near human settlements are under significant pressures from human activities,with negative consequences on their structure and composition.As studies are limited,we assessed the structure and species composition of a portion of miombo woodland along an increasing disturbance gradient from a national park,through a buffer zone to communal lands in northeast Zimbabwe.Five concentric plots of 2 and 11 m radii were established in each area to record woody species composition,diameter,height,basal area,density and volume as well as evidence of disturbance.Effects of site,growth stage and their interaction on vegetation diversity and structural parameters were tested using a general linear model(GLM).Principal component analysis(PCA) tested the association between species and site and ANOVA the differences in the level of disturbance across strata.Species diversity did not differ between sites except for evenness,which increased with disturbance.Evenness and richness were greater in seedlings and saplings than mature trees across sites,respectively.Sapling and mature tree diameters differed significantly between sites.Volume and density of mature trees declined with increasing disturbance while seedling densities peaked at intermediate disturbance levels(buffer zone).Tree harvesting,was more evident in the buffer zone and in the communal area relative to the national park.In contrast,fire frequency was greater in the national park and in the buffer zone relative to the communal area.The results of this study identify a true miombo woodland dominated by Brachystegia boehmii with a stable population,as illustrated by an inverse-J shape in diameter class distribution on all sites,and that these woodlands are generally resilient to disturbances,maintaining similar species composition and structure at various levels of disturbance.However,continued monitoring of disturbance levels and miombo woodland response is recommended to ensure sustainable utilisation of these resources. 相似文献
13.
Although homegardens are most often suggested as the refuges for biodiversity in human-dominated landscapes, how the surrounding landscape and socioeconomic characteristics affect this diversity in the tropics has received little research attention. Hence, this study has examined how these factors affect woody species diversity in homegardens of northeast Ethiopia. Three landscapes which are similar in agroecology were selected and in total 54 households were used for both a survey and a woody species inventory in respondents’ homegardens. The homegardens were stratified based on their locations in relation to crop fields and natural vegetation using satellite images from Google Earth. The variation in Shannon–Wiener diversity index among homegardens and the effect of the socioeconomic factors including household wealth status, homegarden area and the households’ types of uses of woody plants on species diversity were analyzed using one-way ANOVA. Altogether 53 woody plant species belonging to 35 botanical families were identified. Survey results indicated that the woody species diversity was higher in homegardens situated close to crop land as compared with the diversity in homegardens close to natural vegetation. Higher woody species diversity was recorded in homegardens which are larger in area and where the households’ types of uses of woody plants is higher. Moreover, the woody species diversity was found to be higher in homegardens of the high and medium income households when compared with that of poor households. Overall, results suggest that the concurrent ecological and socioeconomic studies are needed to design conservation strategy and policy for plant biodiversity in agricultural landscapes. 相似文献
14.
In the Euro-Mediterranean region, mechanical fuel reduction is increasingly used in response to the mounting occurrence of catastrophic wildfires, yet their long-term ecological effects are poorly understood. Although Mediterranean vegetation is resilient to a range of disturbances, it is possible that widespread fuel management at short intervals may threaten forest structural complexity and the persistence of some plant species and functional types, with overall negative consequences for biodiversity. We used a chronosequence approach to infer woody vegetation changes in the first 70 years after understory clearing in upland cork oak (Quercus suber) forests, and to assess how these are affected by treatment frequency. Across the chronosequence there was a shift between plant communities with contrasting composition, structure and functional organization. Understory cover increased quickly after disturbance and a community dominated by pioneer seeder and dry-fruited shrubs (Cistus ladanifer, C. populifolius, Genista triacanthos, and Lavandula stoechas) developed during about 15 years, but this was slowly replaced by a community dominated by resprouters and fleshy-fruited species (Arbutus unedo, Erica arborea) >40 years after disturbance. During the first 15 years there were rapid increases in woody species richness, vertical structural diversity, cover by Q. suber juveniles and saplings, and shrub cover at <1.5 m strata, which levelled off or slightly declined thereafter. In contrast, tree species richness, tree density and density of arboreal A. unedo and E. arborea, vertical structural evenness, and cover at >1.5 m strata increased slowly for >50 years. Treatment frequency showed strongly negative relationships with species richness, structural diversity and evenness, and horizontal and vertical understory cover, particularly that of slowly recovering species. These findings suggest that fuel reduction programs involving widespread and recurrent understory clearing may lead to the elimination at the landscape scale of stands with complex multi-layered understory occupied by large resprouters and fleshy-fruited species, which take a long time to recover after disturbance. Fuel management programs thus need to balance the dual goals of fire hazard reduction and biodiversity conservation, recognizing the value of stands untreated for >50 years to retain ecological heterogeneity in Mediterranean forest landscapes. 相似文献
15.
Plant species richness and diversity in urban and peri-urban gardens of Niamey,Niger 总被引：1，自引：0，他引：1
Hannah Bernholt Katja Kehlenbeck Jens Gebauer Andreas Buerkert 《Agroforestry Systems》2009,77(3):159-179
Urban and peri-urban agriculture (UPA) significantly contributes to food and nutritional security of urban dwellers in many
African countries. Economic and demographic pressures often lead to transformation of subsistence-oriented traditional homegardens
into commercial production units. Such transformation is claimed to result in decreasing plant diversity, particularly of
local species. A study was therefore undertaken in 51 gardens of Niamey, Niger, to assess the factors determining plant diversity
and the suitability of UPA for in situ conservation of plant genetic resources. In each garden, the number and abundance of
all human-used plant species were determined, and species density, Shannon index and Shannon evenness were calculated. In
the 51 surveyed gardens, a total of 116 plant species were cultivated, most of them for the production of fruits or vegetables.
Annual vegetables dominated, particularly exotic species grown for sale. In the cold season, an average of 14 species were
cultivated per garden, the Shannon index was 0.96 and evenness was 0.39. Commercial gardens had a species richness similar
to that of subsistence gardens, but a lower evenness (P < 0.005), caused by the dominance of a few vegetable species. Gardens of immigrants had a lower Shannon index than those
of members of the local Djerma ethnic group. Stepwise multiple regression analysis showed significant influence of various
variables on plant species richness and diversity parameters: garden size (richness and Shannon index), ethnicity of the gardener
(richness and evenness), gender of the gardener and cash-oriented production (evenness), household size (richness) and garden
possession status (Shannon index). Cluster analysis revealed the existence of five garden types. The highest species richness
and diversity, particularly of perennial and local species, was found in large, peri-urban, commercial gardens managed by
relatively wealthy, elderly gardeners with large families and a regular non-agricultural income. 相似文献
16.
对广东省东莞清溪林场短萼仪花(Lysidice brevicalyx Wei)群落的群落结构及其多样性特点和土壤肥力状况进行了研究。共设置了8个400m2的样方,4个样方设置于连片分布的沟谷林中,其余4个样方设置在山坡上零散分布的大树周围。在调查样方中共记录了维管植物142种,隶属于68科103属。沟谷片生林样方的Shan-non指数高于散生树丛群落,山坡散生树丛样方的物种丰富度和均匀度指数高于沟谷林群落,相似性指数为0.41。两类群落的短萼仪花种群均缺乏小苗和幼树,种群结构呈衰退型。现有短萼仪花群落的土壤肥力与邻近的灌草丛群落相近,但较东莞市荔枝园和人工林地稍高。 相似文献
17.
甜槠林是我国中亚热带地区地带性植被常绿阔叶林的主要类型之一,也是鹰咀界天然林保护区内代表性植被。我们在群落调查的基础上,通过统计计算分析将区内的甜槠林分成3大类别8种群落类型。并分别用物种丰富度指数（Dg1）、Simpson指数（D）、Shannon—Wiener指数（H’）、Pielou均匀度指数（J）、Alatalo均匀度指数（E）对各群落类型进行了物种多样性研究,结论为：群落多样性乔木层、灌木层（不包括乔木幼树、幼苗）〉草本层,但乔木层多样性不一定大于灌木层,灌木层、草本层的分布均匀度较乔木层高,变异系数小。 相似文献
18.
本文对贵州凯里喀斯特区最难恢复的白云质砂石山天然次生灌木林的植物多样性进行了初步研究。对研究区6个样地共计2 400m2植被的调查研究结果表明:白云质砂石山天然次生灌木林木本植物有21科37属49种,草本植物有6科10属15种,植物组成以落叶灌木树种+多年生草本为主;白云质砂石山天然次生灌木林群落各层次的优势种都比较明显,灌木层以金佛山荚蒾Viburnum chins-hanense、火棘Pyracantha fortuneana占优,草本层以五节芒Miscanthus floridulus、白茅Imperata cy-lindrical、荩草Arthraxon hispidus处于优势地位;物种丰富度和多样性特征指数都小,生境资源匮乏是导致白云质砂石山物种丰富度、植物多样性小的主要原因。 相似文献
19.
Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, we studied woody plant structure, diversity and regeneration potentials in 5- and 10-year grazing exclosures in comparison with open grazed sites in a semi-arid environment. Data on species diversity, abundance, structure, basal area, frequency, density, and regeneration status were collected from 270 sample plots. Forty-one woody species representing 20 families were identified, with 18, 28 and 38 species found in open grazed areas, and in 5- and 10-year grazing exclosures, respectively. The 10-year grazing exclosures had a higher (P < 0.05) species richness and plant densities compared to the 5-year grazing exclosures and the open grazed areas. The population structure and regeneration status of woody species in both grazing exclosures showed an inverted J-shape, indicating a healthy regeneration status, whereas hampered regeneration was observed in open grazed areas. The establishment of grazing exclosures had positive effects in restoring woody plant diversity and improving vegetation structure and regeneration potentials of degraded grazing lands. 相似文献