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1.
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   

2.
In this article, we compared the structure, composition, and diversity of trees, shrubs and saplings, seedlings and herbaceous species of community- and government-managed forests in the lowlands of eastern Nepal. Results suggest that among the trees, the community forest was dominated by a single species, Shorea robusta. However, Shorea robusta and Terminalia myriocarpa were codominant in the government forest. Tree density and basal area were higher in the government forest, but shrub/sapling density and basal area were higher in the community forest, suggesting a positive effect of community management on tree regeneration. Overstory species assemblages showed an obvious compositional difference between the forests, but understory species assemblages were less obvious. Plot-level tree and shrub/sapling species richness was higher in the government forest than the community forest. However, seedling-herbaceous species richness was higher in the community forest. The dominance of Shorea robusta trees in the community forest suggests that people involved in managing forests may be more interested in a limited number of economically valuable species while removing less important trees. Such preferential management practices may increase resource heterogeneity within a forest and maintain species diversity in the understory. Thus, community participation in forest management should be encouraged, with guided management techniques and exercises, to achieve maximum forest recovery, provide sustainable ecosystem services, and maintain forest diversity.  相似文献   

3.
Non-coniferous vegetation, including herbs, shrubs, and broad-leaved trees, makes a vital contribution to ecosystem function and diversity in Pacific Northwest conifer forests. However, forest management has largely been indifferent or detrimental to shrubs and trees that have low commercial value, in spite of a paradigm shift towards more holistic management in recent decades. Forest management practices that are detrimental to broad-leaved trees and shrubs are likely to decrease habitat diversity for wildlife, but the number of species that may be affected has not previously been enumerated. I reviewed life history accounts for forest-dwelling vertebrate wildlife species and derived a list of 78 species in Oregon and Washington that are associated with non-coniferous vegetation. The diversity of direct and indirect food resources provided was the primary functional basis for associations of most species with non-coniferous vegetation. Thus, a diversity of herbs and broad-leaved trees and shrubs provides the foundation for food webs that contribute to diversity at multiple trophic levels in Pacific Northwest conifer forests. Given the number of species associated with non-coniferous vegetation in conifer-dominated forests, maintaining habitats that support diverse plant communities, particularly broad-leaved trees and shrubs, will be an important component of management strategies intended to foster biodiversity. Silvicultural practices such as modified planting densities, and pre-commercial and commercial thinning, can be used to control stand density in order to favor the development of understory herbs, shrubs, and a diversity of tree species within managed stands. Allowing shrubs and hardwood trees to develop and persist in early seral stands by curtailing vegetation control also would benefit many species associated with non-coniferous vegetation.  相似文献   

4.
In this study we analysed: (1) the biodiversity conservation capacity of Agroforestry Systems (AFS) in temperate highlands of the Tehuacán–Cuicatlán Valley, Central Mexico, (2) human cultural motives and actions for conserving such diversity and (3) problems endangering that capacity. We evaluated the richness and diversity of perennial plant species maintained in AFS through vegetation sampling of 14 agricultural plots and compared their composition with that of natural forests (14 plots of 500 m2 each). We examined the situations among communities of Náhuatl, Ixcatec and Cuicatec people, documenting through interviews the management practices of plant species and the whole system, reasons why people maintain vegetation cover within AFS, and factors influencing changes in decisions favouring agriculture intensification. In the AFS studied we recorded a total of 79 species of trees and shrubs, 86 % of them being native species and representing 43 % of all species of trees and shrubs recorded in the sampling of the natural forests the AFS derive from. People leave standing on average a total of 40 individual trees and shrubs per agricultural plot. Reasons for leave plant species standing were more frequently associated with their use as fruit trees, firewood, shade, beauty, respect to nature and other environmental benefits. Water availability for irrigation, land tenure, and dependence on agriculture and forest for peasant's subsistence were main decision factors influencing AFS variation in their composition. AFS in temperate zones are important reservoirs of biodiversity and biocultural heritage and should be keystones for conservation policies in the Tehuacán–Cuicatlán Valley.  相似文献   

5.
何涛 《绿色科技》2014,(4):26-30
指出了灌丛是陆地生态系统的重要组成部分,亚热带亚高山灌丛具有物种组成、分布与形成的特殊规律,研究其结构组成特征对于亚高山生物多样性保护具有重要的意义。对林芝地区亚高山落叶阔叶灌丛进行了实地调查,测定了株高、密度、盖度、冠幅等指标,记录了海拔、地形、经纬度等因子,分析了植物科属组成特点、物种丰富度、物种多样性、重要值等研究灌木群落的结构特征,为林芝地区亚高山落叶阔叶灌丛的合理利用、开发和保护提供理论依据。  相似文献   

6.
Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura.Overall 10,957 individual trees belonging to 46 family,103 genera and 144 species were counted at ≥30 cm DBH(diameter at breast height) using 28 permanent belt transects with a size of 1 ha(10 m × 1000 m).Four different tree communities were identified.The primary forests was dominated by Shorea robusta(mean density 464.77 trees ha-1,105 species) and Schima wallichii(336.25 trees ha-1,82 species),while the secondary forests was dominated by Tectona grandis(333.88 trees ha-1,105 species) and Hevea brasiliensis(299.67 trees ha-1,82 species).Overall mean basal area in this study was 18.01m 2 ·ha-1 ;the maximum value was recorded in primary Shorea forest(26.21 m 2 ·ha-1).Mean density and diversity indices were differed significantly within four different communities.No significant differences were observed in number of species,genera,family and tree basal cover area.Significant relationships were found between the species richness and different tree population groups across the communities.Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumulation of native oligarchic small tree species.Seventeen species were recorded with <2 individuals of which Saraca asoka(Roxb.) de Wilde and Entada phaseoloides(L.) Merr.etc.extensively used in local ethno-medicinal formulations.The present S.robusta Gaertn dominated forest was recorded richer(105 species) than other reported studies.Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests.Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur.The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T.grandis L.dominated community.  相似文献   

7.
High Andean cloud forests are home to a diversity of unique wildlife and are important providers of ecosystem services to people in the Andean regions. The extent of these cloud forests has been widely reduced through conversion to pasture for livestock, which threatens the forests’ ability to support biodiversity and provide ecosystem services. This paper explores whether impacts on woody plant biodiversity and four ecosystem properties (woody plant species richness, juvenile timber tree abundance, soil organic matter content and soil moisture) from converting forest to pasture can be mitigated if some woody forest vegetation is maintained within pastures. Woody vegetation in pastures was found to conserve those woody plant species that are more tolerant to exposure and grazing, but conservation of the high montane cloud forest community required areas of forest from which livestock were restricted. The sampled sites clustered according to woody plant species cover; these clusters represented a gradient from pasture with patches of shrubs to mature forest. Clusters differed in both woody plant species richness and number of juvenile timber trees whereas soil organic matter and soil moisture were observed to be similar among all clusters. This suggests that the different habitats may have some equivalent ecosystem properties. We conclude that the presence of woody vegetation in pastures may reduce some of the impacts of converting forest to pasture, but should not be considered a substitute for protecting large areas of forest, which are essential for maintaining woody plant species diversity in high Andean cloud forest.  相似文献   

8.
This paper describes an attempt to predict ground flora species richness under various forest management scenarios. The approach is based on a geographic information system (GIS) and uses three standard map layers of topography, soils and stands to derive environmental gradients of light, nutrients, water and disturbance. A simple floristic survey provides the data necessary to relate plant distribution with environmental variables. The potential distribution of 60 understorey plant species is modelled based on the four derived gradients. The sum of these maps, i.e., the total potential diversity, is used as a proxy for the prediction of actual species richness. The model predicts high species diversity along roads and in relatively disturbed areas and low species diversity in stands with coniferous species and in stands of old, deciduous trees (mainly beech). The overall predicted pattern of species diversity corresponds well with observations made in the forests. However, the model explained only a fraction of the variation in the data set on the plot level. Dispersal effects, demographic stochasticity and biological factors are the probable causes of this. The combination of GIS-based spatial operations and fuzzy cognitive mapping proved to be an efficient way of producing gradient maps based on standard forestry maps and expert knowledge.  相似文献   

9.
Old growth stands of boreonemoral spruce (Picea abies) forests frequently have a shrub layer dominated by hazel (Corylus avellana) – a species which is generally excluded in intensively managed forests due to clearcutting activities. We sampled understory species composition, richness and biomass, as well as environmental variables beneath these two species and also within forest ‘gaps’ in order to determine the effect of overstory species on understory vegetation. Species richness and biomass of herbaceous plants was significantly greater under Corylus compared with plots under Picea and in forest gaps. Indicator species analysis found that many species were significantly associated with Corylus. We found 45% of the total species found under woody plants occurred exclusively under Corylus. Light availability in spring and summer was higher in gaps than under forest cover but no difference was found between plots under Corylus and Picea. Hence, reductions in light availability cannot explain the differences in species composition. However, Ellenberg indicator values showed that more light demanding species were found under Corylus compared to Picea, but most light demanding species were found in gaps. The litter layer under Picea was three times thicker than under Corylus and this may be an important mechanism determining differences in understory composition and richness between the woody species. The presence of Corylus is an important factor enhancing local diversity and small-scale species variation within coniferous stands. Hence, management should maintain areas of Corylus shrubs to maintain understory species diversity in boreal forests.  相似文献   

10.
霸王岭林区是海南岛最典型的热带山地雨林分布区.在该区,现存分布面积最广、资源数量最大的是热带山地雨林的各种伐后林.以霸王岭分布最广的以陆均松(Dacridium pierrii)为主的山地雨林的伐后林为对象,研究了其组成、径级、高度结构和物种多样性特征,对比分析了伐后林与原始林以及伐后林不同类型之间的异同.结果表明:原始热带山地雨林经采伐后中小乔木和灌木的优势度增大,而大乔木树种的优势度则明显下降.阳性树种的种类、数量和相对重要性随采伐破坏的程度而增加.伐后林中矮、小树木在林分中比例随采伐破坏的程度增加,而高、大树木,特别是进入主林层树木的比例则随采伐破坏的程度明显下降.从林分测树因子的变化来看,采育择伐和径级择伐的林分要优于大强度择伐和皆伐的林分.原始林的物种丰富度大于伐后林,但其多样性指数和均匀度指数大都小于伐后林.组成上与原始林相似性较大的伐后林是各种择伐后的林分,而皆伐后的林分与原始林在组成上已有很大差别.  相似文献   

11.
The distribution of plant species has always been altered by changing climatic conditions. Nonetheless, the potential for species’ range shift responses has recently become severely limited, as exceptionally fast temperature changes coincide with a high degree of anthropogenic habitat fragmentation. This study provides rare insights into the effects current temperature increases have on pristine temperate forest ecosystems, using the forests of Changbai Mountain, NE China, as a case study. On the northern slopes of the mountain at elevations between 750 and 2100 m, the composition of trees, shrubs and herbaceous species was recorded on 60 plots in 1963 and 2006/07. Multiple linear regression (MLR) and canonical correspondence analysis (CCA) were used to establish the response of plant diversity and plant distribution patterns to environmental conditions. Climatic factors proved important in explaining the spatio-temporal trends within the vegetation. The composition of dominant trees remained mostly unchanged over the last 43 years, reflecting a very slow response of the forest canopy to environmental change. The composition of young trees, shrubs and herb species showed varied changes in the different forest types. A homogeneous species composition in the cohort of regenerating trees indicates an increased future uniformity in the mixed broadleaved and coniferous forest. The understory vegetation of high elevation birch forests was invaded by floristic elements of the lower-elevation coniferous forests. Both these trends pose potential threats to forests plant diversity. Future research investigating climate change responses in forest canopy composition needs to be based on even longer timescales, while investigations in the near future need to pay particular attention to the changes in the distribution of rare and threatened herbaceous species.  相似文献   

12.
To address the pressing need to evaluate how conifer plantations can serve biodiversity functions in addition to other economic and social roles they play, we assessed the diversity of broad-leaf seedlings and saplings in Cryptomeria japonica plantations in Ogawa, Ibaraki Prefecture, Japan at increasing distances (0–1000 m) from old growth natural forest edge. For saplings, there was no overall significant trend in the frequency, species richness, and Shannon index with respect to distance. Seedlings on the other hand showed a decrease in frequency and species richness with increasing distance from the old growth forest, implying that should recruitment limitation occur in the plantations, it will be stronger at the seed-to-seedling transition than at the seedling-to-sapling transition. Assigning species into groups based on functional traits that are associated with recruitment and regeneration was more revealing. Relative frequency of species that are moderately shade-tolerant, are shrubs, have small seeds, and are frugivore-dispersed increased in the plantations. In comparison, species that are tall trees, have large seeds and are gravity-dispersed decreased in the plantations. Multi-trait analysis showed that propagule size was the trait that could best explain the difference in the distribution of broad-leaf species in the plantations. Based on our results, we suggest to policy-makers that plantation sizes be kept to within a few hundred meters wide, and should ideally be within dispersal distance of species from natural forests that could potentially be seed sources of broad-leaf species. Otherwise, steps must be taken to drive succession such that potentially recruitment-limited species may be able to overcome barriers to regeneration.  相似文献   

13.
研究了贵州茂兰自然保护区喀斯特峰丛中部典型常绿落叶阔叶混交林的群落特征、群落内种子植物的区系特点以及群落物种多样性。结果表明:茂兰喀斯特峰丛中部常绿落叶阔叶混交林群落由乔、灌、草及层间藤本植物组成,种类组成丰富,样地(1 800 m2)共有植物146种,分属55个科,其中种属比较多的科有樟科、壳斗科、山茱萸科、胡桃科、榛科等,群落无明显优势树种;群落以常绿树种、革质叶、高位芽植物为主;群落的植物区系与泛热带植物区系和热带亚洲植物区系的关系最为密切,热带、亚热带分布的属占65.31%,群落具有明显的热带亚热带植物区系特征。群落物种多样性指数、均匀度指数,生态优势度指数较高,群落结构复杂、稳定。  相似文献   

14.
地带性木本植物群落功能型的水热分布格局   总被引：3，自引：0，他引：3  
王国宏 《林业科学》2002,38(1):15-23
植物功能型是对环境条件做出相似的反应和对关键生态学过程具有相似影响的植物组合。不同功能型植物对生态系统过程的作用不同 ,通过植物功能型的分析对揭示生态系统功能至关重要。甘肃省境内 5种地带性木本植物群落 (亚热带常绿落叶阔叶林、暖温带落叶阔叶林、温带针阔混交林、寒温性针叶林和荒漠旱生灌木群落 )依据植物体的高度、叶片的生长对策及果实类型可划分出 2 3种功能型。其分布格局与水热因子的相关分析表明 :1)湿热的生境利于乔木、大灌木、藤木、寄生植物和常绿植物及翅果、坚果、核果、果、颖果类植物的发育 ,干冷生境利于灌木、小灌木和落叶植物以及蒴果类植物的发育。 2 )干果类和肉果类的成因可能与植物生长环境中水分供应状况密切相关 ,即潮湿的生境利于肉果类植物的发育 ,干旱的生境有利于干果类 (如胞果 )的发育。 3)研究区域地带性木本植物群落物种丰富度和功能型的丰富度格局主要受制于水分梯度影响 ,而良好的水热组合可孕育木本植物群落最丰富的果实类型。  相似文献   

15.
Estimating large herbivore density has been a major area of research in recent decades. Previous studies monitoring ungulate density, however, focused mostly on determining animal abundance, and did not interpret animal distribution in relation to habitat parameters. We surveyed large ungulates in the Biodiversity Exploratory Schorfheide-Chorin using faecal pellet group counts. This allowed us to explore the link between relative ungulate abundance, habitat use, and browsing damage on trees in a region with several types of forest, including unharvested and age-class beech forests, as well as age-class pine forests. Our results demonstrate that roe deer and fallow deer relative abundance is negatively correlated with large tree cover, and positively correlated with the cover of small shrubs (Rubus spec., Vaccinium spec.), and winter food supply. Habitat use of roe deer and fallow deer, as estimated by counting faecal pellet groups, revealed a preference for mature pine forests, and avoidance of deciduous forests. This differential habitat use is explained by different distributions of high quality food resources during winter. The response of deer to understory cover differed between roe deer and fallow deer at high cover percentages. The amount of browsing damage we observed on coniferous trees was not consistent with the relative deer abundance. Browsing damage was consistently higher on most deciduous trees, except for beech saplings which sustained less damage when roe deer density was low. Because roe deer is a highly selective feeder, it was reported to affect tree diversity by feeding only on trees with high nutritional value. Consequently, we propose that managing the number of all deer species by hunting is necessary to allow successful forest regeneration. Such an adjustment to deer numbers would need to account for both current tree diversity and alternative food resources. Our findings may be applicable to other forest landscapes in northeastern Germany including mature pine stands and differently harvested deciduous forests.  相似文献   

16.
This study was done using the non brown fractal model to quantify and compare the variations in the species richness of trees, shrubs, herbs and all plants along an altitudinal gradient and to characterize the dominating ecological processes that determine the variations. Two transects were sampled far away from any anthropogenic disturbances along the shady slopes of the Dongling mountains in Beijing, China. Both transects were continuous and 2 m wide, and every individual tree and shrub was recorded in each of them. Discrete quadrats of 1 m × 1 m were located along the transects A and B for estimation of the herb species richness along the altitudinal gradients. The level interval between the quadrats was 10 m and 25 m respectively. In this study, transects A and B were combined into one transect AB, and 40 m was selected as the optimal quadrat length along the altitudinal gradients for measuring the plant species richness patterns. Species richness in each quadrat was calculated using a program written in Matlab 6.0. Direct gradient analysis was used to describe the overall trends in the species richness of trees, shrubs, herbs and other plants with change in altitude, while the non-brown fractal model was used to detect more accurately their variations at various scales along the gradient. The model assumed that each class of ecological processes affecting the distribution of a variable could be represented by an independent spatial random function. Generally, ecological phenomena are determined not by a single ecological process but by multiple ones. These processes act on ecological patterns within their own spatial scales. In the non-brown fractal model, the spatial random functions are nested within a larger range of spatial scales. The relative contribution of the spatial random functions to the spatial variation of a variable is indicated by a weighting parameter that has to be greater than or equal to zero. In this paper, we reached the following results and conclusions. Firstly, the direct gradient method describes the general trends of trees, shrubs, herbs and all plants along the altitudinal gradient but is unable to provide further details on the altitudinal variations in the species richness. The non-brown fractal model brought out the altitudinal variations in the species richness of trees, shrubs and herbs at various scales and related them to the ecological processes. The sharp changes in the double-log variograms suggest that the non-brown fractal model is suitable for characterizing the altitudinal patterns in the species richness of trees, shrubs and herbs at various scales but is not appropriate for explaining the variations in the plant species richness, since no significant changes were found in the double-log variograms in this case. Secondly, for the trees, the double-log variogram was divided into two scale ranges (0–245 m and 245–570 m), with a fractal dimension of 1.83 and 1.10, respectively, implying that changes in the tree species richness were random at small scales (0–245 m) and almost linear at large scales (245–570 m) along the altitudinal gradients. This suggests that altitudinal variations in the tree species richness are dominated by short-range processes at small scales and by long-range processes at large scales. Thirdly, for shrubs and herbs, the double-log variograms exhibited three ranges (0–101 m, 125–298 m and 325–570 m), and the fractal dimensions were 1.78 and 1.97, 1.56 and 1.43, and 1.08 and 1.25, respectively. The results indicate that, as in the case of trees, species richness of shrubs and herbs are distributed randomly at small scales and change in a linear manner at large scales although variations in the herb species richness is less heterogeneous than shrub species richness at large scales. These results also indicate that species richness of shrubs and herbs change approximately like brown movement at middle scales. The results also suggest that altitudinal variations in the specie richness of shrubs and herbs are dominated by three ecological processes, short-range ecological processes at small scales, long-range ecological processes at large scales, and brown fractal processes at middle scales. Interestingly, comparisons of the variations in the species richness of shrubs and herbs reveal that shrubs and herbs present the same scale range in spatial variation in species richness but display different trends in species richness along the altitudinal gradient, i.e. the shrub species richness decreased with increasing elevation whereas the herb species richness peaked at the mid-high elevation. These patterns suggest that although the scales at which the main processes affect patterns in species richness are the same, the processes are completely different, or the processes are similar but the responses of the shrubs and herbs to the ecological processes are different. Finally, the plant species richness did not show any obvious pattern along the altitude gradient and maintained a constant fractal dimension across all scales, this is perhaps because the processes defining the patterns of plant species richness had similar weights and acted over closely related scales. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(6): 901–909 [译自: 植物生态学报]  相似文献   

17.
Selection harvesting, by mimicking natural disturbance regimes of eastern deciduous hardwood forests, has been applied as a sustainable management practice that combines wood production with biodiversity conservation. However, the effects of this technique on understory herbs are unclear, particularly for spring ephemerals which have been suggested as sensitive to disturbance. Here, we experimentally assess the immediate effects of single-tree and group selection harvesting on spring ephemeral richness, diversity and abundance in deciduous forests of southwestern Ontario, Canada. Spring herbs were quantified in 4 m2 plots before and one growing season after harvesting and compared to similar uncut, reference stands. The percent of species lost was significantly higher in reference than harvested plots. Mean species richness significantly increased after harvesting, predominately due to an increase in spring–summer species. Increases in the diversity of early spring flowering species were significantly greater in the group selection plots than reference plots. At the community level, no species appeared to be vulnerable to harvesting, and ordination analysis indicated that post-harvest communities were primarily determined by pre-harvest community composition. Furthermore, no species declined in abundance in response to harvesting, and overall percent cover increased proportionately more in single-tree selection plots than in group selection or reference plots. While harvesting appears to have negligible effects on spring ephemerals immediately following harvest, we recommend additional studies over longer time frames to assess possible successional effects and to discriminate treatment induced changes from naturally high yearly variation in species composition.  相似文献   

18.
A study was conducted in Tara Gedam and Abebaye forests l,northwestern Ethiopia to investigate the diversity,regeneration status,socio-economic importance and the factors causing destruction of the forests.A total of 30 plots,measuring 20 m ×20 m,were established along line transects laid across the forests.Participatory Rural Appraisal (PRA) method was employed to generate the socio-economic data.Primary data were collected by field observation,semi-structured interview with key informants and discussion with relevant stakeholders.A total of 143 woody species belonging to 114 genera and 57 families were recorded,and of all the species 44 (30.8%) were trees,57 (39.9%) trees/shrubs,33 (23.1%) shrubs and 9 (6.3%) lianas.The diversity and evenness of woody species in Tara Gedam forest are 2.98 and 0.65,respectively,and in Abebaye forest they are 1.31 and 0.31,respectively.The total density and basal area of woody species in Tara Gedam forest are 3001 individuals ha-1 and 115.36 m 2 ha-1,respectively,and in Abebaye forest the values are 2850 individuals ha-1 and 49.45 m 2 ha-1,respectively.The results on the importance value index (IVI) and DBH class distributions suggest that the species with low IVI value and poor regeneration status need to be prioritized for conservation.In the socio-economic survey,the responses from the key informants indicatedthat the forests are the major sources of fuelwood (90%),construction material (80%),timber (75%) and farm implements (55%).The forests are also sources of medicines,animal fodder,bee forage and edible fruits.Tara Gedam monastery,assisted by the local people who have strong religious belief and high respect to the monastery,has played a great role in the maintenance of the sacred forest since a long time.At present,the conservation efforts are made jointly by the monastery and institutions concerned with conservation.The major factors that cause destruction of the forests are livestock grazing,tree cutting for various purposes and farmland expansion.The implications of the results are discussed,and the recommendations are suggested for conservation,management and sustainable utilization of the forest ecosystems.  相似文献   

19.
辽东山区次生林植物物种多样性研究   总被引：1，自引：0，他引：1  
通过对辽东山区18块样地的调查及数据处理,计算出各样地乔木、灌木、草本的Margalef丰富度指数、Gini均匀度指数和Simpson多样性指数。从调查及分析结果来看,在本研究区域内,海拔高度对调查区域内的物种多样性影响不大,郁闭度、坡向、坡度对物种多样性有一定影响。  相似文献   

20.
在调查群落种类组成的基础上,对三峡库区3种典型森林主要组成树种的种群结构进行分析,并推断群落的演替趋势.结果表明:1)三峡库区森林群落乔木层优势种主要为马尾松、柏木等针叶树种,短柄袍栎、栓皮栎等落叶阔叶树种及多脉青冈、石栎等常绿阔叶树种;2)针叶群落中乔木层个体高度级频度顶点位于10～15 m,针阔混交群落与阔叶群落为5～10 m;3)阔叶群落中短柄袍栎和栓皮栎等优势种的胸径频率为逆J字型,伴生树种主要为L型或逆J字型,主要组成树种的种群结构表明优势种种群处于稳定状态;4)针阔混交群落针叶优势种的种群属于单峰型和逆J字型的衰退类型,阔叶树种多为逐渐增长的L型或间歇性发展的多峰型;5)针叶群落优势树种胸径频率属于典型的单峰型,伴生树种为单柱型或L型;6)由主要组成树种的种群结构推断三峡库区森林群落演替过程为针叶林群落→针阔混交林群落→常绿阔叶林群落.研究结果为三峡库区生态建设和森林资源管理提供科学依据.  相似文献   

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