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1.
Microbial population and activity can be influenced by changes in the physical and chemical conditions of the soil. The objective of this study was to compare fungal diversity under different agricultural management systems and associated differences in soil properties. This research was carried out in three areas, representing the Atlantic Forest, AFS and cassava (Manihot esculenta Crantz) monoculture system. Five composite samples were collected during the rainy and dry seasons from each area. Using the composite soil samples, fungal isolation was carried out using a serial dilution technique. Physical, chemical and DGGE analyses of the filamentous fungi community were performed. The fungal isolation data were used to calculate ecological indices of diversity, species richness, equitability, dominance, similarity and density. In general, Atlantic Forest soil presented the highest ecological indices followed by the AFS. The DGGE technique revealed that the structure of the soil mycobiota of the Atlantic Forest and AFS are more than 50% similar. The data indicate that the similarity of the structure and composition of soil mycobiota between AFS and Atlantic Forest is mainly due to the conservation of above-ground plant diversity, and the conservation of soil characteristics can be attributed to the absence of pesticides and fertilizers.  相似文献   

2.
Traditionally, most cocoa farms are established by removing the forest understorey and thinning the forest canopy so that cocoa seedlings can grow into productive trees by utilising the forest rent of the newly cleared area and the shade provided by the remaining trees. With the introduction of new hybrid cocoa varieties, there is a gradual shift towards the elimination of shade trees in the cocoa landscape. Farmers have found it necessary to eliminate forest tree species to effect high performance of these new varieties and as a result large areas of forested land are being lost, thereby posing a threat to biodiversity A study was carried out in Atwima, a major cocoa farming district in the Ashanti region of Ghana, to assess the impact of cocoa cultivation on tree diversity. The study also investigated farmers’ preferences for tree species retained on cocoa farms as well as their traditional knowledge on tree species and their effect on cocoa cultivation. The assessment consisted of identification and enumeration of all tree species with diameter at breast height greater than or equal to 10 cm, and was carried out on one-hectare plots of: (a) Active Cocoa Farms (ACF), stratified into (i) Mature Cocoa Forest (MCF) and (ii) Young Replanted Cocoa (YRC); (b) Fallow land (FL), and (c) Natural Forest (NF). A total of four one-hectare plots replicated five times (or 20 ha) were enumerated. Tree diversity was more strongly influenced by landuse type than age of cocoa farm. Fallow lands contained a higher tree diversity followed by natural forest, with the active cocoa farms, both mature and young, containing the lowest variety of species. However, stem count was highest in the natural forest followed by FL and ACF. Generally, stem counts of important tree species, as well as those classified as either endangered or vulnerable, were extremely low in the landscape (0–2 per hectare), indicating a critical potential for conservation and rejuvenation. Farmers’ preference for trees on cocoa farms was based on their usefulness. Three categories of trees emerged from their classification of trees on cocoa farms: (i) naturally occurring trees that are very useful; (ii) naturally occurring species of minor economic use; and (iii) naturally occurring tree species that are aggressive or incompatible with cocoa. Multistrata cocoa farms are a potential niche for conservation, but given the current trends in cocoa replanting, future conservation strategies will have to focus on identified targeted species which are of conservation concern, as well as those that are of value to farmers.  相似文献   

3.

Context

Prediction of the effect of harvests and climate change (CC) on the changes in carbon stock of forests is necessary both for CC mitigation and adaptation purposes.

Aims

We assessed the impact of roundwood and fuelwood removals and climate change (CC) on the changes in carbon stock of Finnish forests during 2007–2042. We considered three harvest scenarios: two based on the recent projections of roundwood and fuelwood demand, and the third reflecting the maximum sustainable cutting level. We applied two climate scenarios: the climate was in the state that prevailed around year 2006, or it changed according to the IPCC SRES A1B scenario.

Methods

We combined the large-scale forestry model MELA with the soil carbon model Yasso07 for mineral soils. For soils of drained, forested peatlands, we used a method based on emission factors.

Results

The stock change of trees accounted for approximately 80 % of the total stock change. Trees and mineral soils acted as carbon sinks and the drained peatland soils as a carbon source. The forest carbon sink increased clearly in both of the demand-based scenarios, reaching the level of 13–20 Tg C/year (without CC). The planned increase in the use of bioenergy reduced the forest sink by 2.6 Tg C/year. CC increased the forest carbon sink in 2042 by 38 %–58 % depending on the scenario. CC decreased the sink of mineral soils in the initial years of the simulations; after 2030, the effect was slightly positive. CC increased the emissions from the drained peatland soils.

Conclusions

It is likely that forest land in Finland acts as a carbon sink in the future. The changes in carbon stocks of trees, mineral soils, and peatland soils respond differently to CC and fuelwood and roundwood harvests.  相似文献   

4.
Studies were carried out on the arbuscular mycorrhizal (AM) fungal association in four potential timber yielding tree species from four forest areas of the Western Ghat region of Goa, India. The edaphic factors selected for the study varied within the four study sites. Significant positive and negative correlations were exhibited between spore density and root colonization of AM fungi at two sites, Collem and Dharbandoda. The study recorded the presence of 21 AM fungal species belonging to three genera—viz., Acaulospora, Gigaspora, and Glomus. The present study suggests that there is a site specific variation in root colonization (except at Mollem) and spore density as well as edapho-specific variation in association, composition, and distribution of AM fungi associated with potential timber yielding trees from four forest areas in the Western Ghat region of Goa. Further investigations of AM fungal dynamics if carried out can help elucidate the ecological significance of AM fungal associations in the Western Ghat region of Goa. To add, learning more about the ecology and intricacies of the AM association is crucial for attaining a good understanding of its life cycle and functions in edapho-climatic conditions of the Western Ghat region of Goa to further use it in the management of reforestation practices.  相似文献   

5.
Coffee agroforestry is a conservation strategy that has shown promise to support the diversity of bird, bat, and insect communities, but few studies have focused on non-volant mammals in coffee farms. We assessed mammal diversity within coffee agroforestry systems in Kodagu, India and investigated the impacts of the non-native shade tree species, Grevillea robusta, on mammal diversity. Twenty farms, with varying amounts of G. robusta planted within the coffee farm, were sampled throughout three rainfall zones during the 4-month study period. We captured six species of small mammals, with indirect methods yielding an additional five species, totaling 11 mammal species. Contrary to current ecological thought, we found that increased amounts of G. robusta did not have a negative impact on either abundance or richness of mammals. Small mammal abundances were higher at farms with greater amounts of herbaceous ground cover and larger, mature shade trees, while small mammal species richness was found to increase with an increase in tree species richness as well as greater amounts of herbaceous ground cover. Additionally, small mammal abundance was higher at coffee farms closer to forested areas. Based on these findings, we suggest the maintenance or cultivation of shade tree richness, mature shade trees, and herbaceous ground cover within coffee farms and preservation of forested areas within the landscape to enhance coffee agroforestry habitat for non-volant mammals. We hope that these habitat requirements will be incorporated into conservation strategies for the promotion of biodiversity within coffee agroforestry systems.  相似文献   

6.
The conversion of silvopasture to different land use systems cause effective changes in soil carbon distribution, due to disturbances in soil aggregation promoted by soil management and changes in crop residues inputs and decomposability. We evaluate the C and N stocks, and organic C fractions in soils under continuous arable land (AR) and silvopasture with apple trees and grass (SP); and after 4 years of conversion from silvopasture to arable land (SP-AR) and grassland (SP-GL). Total N (TN) and organic C (TOC), as well as microbial biomass carbon (CMB), light fraction (CLF) and heavy fraction (CHF) were evaluated at two different depths (0–10 and 10–20 cm). After 4 years of conversion, SP-AR and SP-GL presented C and N stocks similar to the observed for SP when the 0–20 cm depth was considered. However, AR presented TOC and TN stocks around 21 and 10% lower than SP, respectively. SP-AR tended to present the lowest CMB stocks and was positively correlated with salt extractable organic C (r 2 = 0.60, P < 0.001). CLF values declined by 62% from 0–10 to the 10–20 cm at SP and SP-GL, however there was no variation with increasing depth for AR and SP-AR. CHF represented the highest C fraction in soil, corresponding to 82% of TOC. Except for AR, δ13C values of the light fraction increased with increasing depth. In general, heavy fraction tended to be more enriched in δ13C than light fraction. In a long-term, conventional tillage can significantly contribute to reduce TOC and TN stocks when compared to the silvopastoral system.  相似文献   

7.
Arora  Raavi  Sharma  Vivek  Sharma  Sandeep  Maini  Asima  Dhaliwal  S. S. 《Agroforestry Systems》2021,95(8):1479-1491

The soil biochemical properties are sensitive to change in land use systems and seasons. The variations in soil management practices and soil moisture content affect the sustainability of the systems. To study the sustainability in lower Shiwalik, a total of 144 soil samples (0–0.15 m) were undertaken to monitor the changes in the soil biochemical properties under rainfed land use systems, i.e., agri-horticulture, agroforestry, cultivated and barren system and seasons, i.e., summer, rainy and winter. Among soil biochemical properties, soil microbial biomass carbon, soil microbial quotient, dehydrogenase activities, basal soil respiration, fluorescein diacetate and urease activities ranged from 77 to 122 μg g?1, 0.023 to 0.027, 18.3 to 30.6 μg TPF g ?1 h?1, 13.2 to 22.7 μg CO2-C g?1 day?1, 1.3 to 2.2 μg g?1 and 5.83 to 6.38 μg NH4-Ng?1 h?1, respectively. Among 15 soil properties, principal component analysis specified that four major soil properties, i.e., basal soil respiration, metabolic quotient, electrical conductivity and clay content contributed 73% of the soil quality index with contribution of 44, 13, 9 and 7%, respectively. Among seasons, the values for soil biochemical properties were higher in rainy season as compared to winter and summer season. In systems, agri-horticulture followed by agroforestry was the best systems in terms of sustainability in Shiwalik foothills of northwest India.

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8.
Tropical forests are the world’s largest terrestrial storehouses of carbon and are recognized as rich, diverse and highly productive ecosystems. The present study was conducted to characterize the land use, diversity and biomass of tropical forest in Western Ghat of Maharashtra State in India through satellite remote sensing and GIS. The study has been designed and implemented to promote analysis on Western Ghat biodiversity resources including trees, shrubs and herbs based on inventorying, monitoring and mapping. Field measured biomass is integrated with spectral responses of various bands and indices of the Landsat TM satellite image for estimation of above-ground biomass in a 36,046 km2 area of relic forest in the Central Western Ghat. The above-ground biomass from field-based inventory varied from 30.2 to 151.1 ton/ha in moist deciduous forest, 9.2–99.1 ton/ha in dry deciduous forest, 42.1–158.6 ton/ha in semi-evergreen forest, and 160.9–271 ton/ha in evergreen forest. The total above-ground biomass of the study area was estimated to be 95.2 M tons. A regression equation between field above-ground biomass and a Normalized Difference Vegetation Index was used for spectral modeling to estimate and prepare the above-ground biomass map in the region. A total 120 plant species in 81 genera and 31 families were identified in the study area. This study emphasizes the importance of relic forests for their biodiversity, carbon sequestration and total biomass.  相似文献   

9.
Plants diversity and phenological pattern of the trees were monitored in a montane wet temperate forest (shola) in the  相似文献   

10.
Woodsurfaceroughnessisthemicrogeometrypropertycomposedbyalittlespacingandpeak-tovalley.Generallythesurfaceroughnesswascomposedbytheworkingmethodandotherfactorst123.Woodsurfaceroughnesswasnotonlyanimportantindexwhichmeasuredthesur-facesmoothextentofwoodproductandtheworkingqualitybutalsothewoodsur-fitceroughnessaffectedwoodsurfacefeel--lngandpsychologicalfeeling[3'4,lo,ll:.Th,'quantitativesurftlceproPertyparametersweretheimportantpartwhichmarkedthewoodsurfacevisualpsycho1ogicalmagni-tude,whichha…  相似文献   

11.
厦门白蚁种类名录与常见白蚁的防治   总被引:1,自引:1,他引:1  
记载厦门白蚁种类4科12属21种,其中9种为厦门新记录种。为害林木的主要有家白蚁、黑翅土白蚁、黄翅大白蚁,介绍了此3种白蚁常见寄主及防治方法。  相似文献   

12.
We compared patterns of acorn dispersal and predation by wood mice among four tree species (Quercus serrata, Quercus crispula, Castanea crenata, and Juglans mandshurica var. sieboldiana) that are abundant in cool temperate woodlands. We devised an acorn dispersal experiment using 400 magnet-inserted acorns and a magnetic locator in a 1.8-ha study plot, which spanned a cut-over area and an adjacent deciduous forest. Ten wire mesh baskets, each containing 40 acorns (10 acorns per species), were placed on the border between these two habitat types. About 13.0% (n = 52) of the total acorns remained in the baskets, while 77.3% (n = 309) were dispersed throughout the study plot and subsequently retrieved using the magnetic locator. Microhabitat, distance, and burial depth of transported acorns were significantly different among species. In the cut-over area, J. mandshurica var. sieboldiana acorns were dispersed under fallen trees or branches and near stumps, and were buried deeply in the soil. Dispersal distances of J. mandshurica var. sieboldiana acorns were significantly greater than those of Q. serrata acorns. The number and microhabitat of transported acorns significantly differed between habitat types. J. mandshurica var. sieboldiana acorns were dispersed in the cut-over area rather than in the forest. For all four species, the numbers of acorns delivered to fallen trees or branches, stumps, and crumbled soil with overhang under any vegetation type were greater in the cut-over area than in the forest.  相似文献   

13.
14.
In order to precisely assess the role of agroforestry for the conservation of (agro-)biological diversity there is a need to adjust sampling methods used in plant sociology. This study is on the contribution of agroforestry land use to the in-situ conservation of indigenous trees within a typical East-African smallholder farming system in Western Kenya. A modified approach to measuring species richness and abundance is presented. The selection of tree-rich structures was done according to management patterns rather than considering syntaxonomic classifications from the vegetation science point of view. This approach, which is better suited to the strongly human-influenced vegetation of agroecosystems, employs between-management unit diversity measures to help evaluate abundance and constancy of species in particular management units. The predominant off-farm vegetation patterns are riverine forests, rocky hillsides, hedgerows, wooded grassland relicts, woodlands or colline forest relicts and tree groves whereas the noticeable tree-rich on-farm management units are homegardens, homesteads, life fences, coffee- and banana-groves and annual cropping fields. 98% out of all indigenous tree species known from Bungoma, occur in off-farm lands. 53% of the indigenous tree species occur in tree rich on-farm management units while 47% of the indigenous trees are dependent on the maintenance of off-farm lands. Hedgerows embody the most promising secondary vegetation structure that shows ample potential to accommodate a wide range of indigenous perennial species outside the natural vegetation formations. The pattern of distribution of various vegetation structures, and the mixture with diverse tree-based on-farm plots are interesting features in regard to floristic and eco-diversity on a landscape level. In this respect, three areas that show different population densities and distinct agro-historical conditions were compared. In regions of particular high population density the degree of association of various functional land use forms and woodland structures – each characterised by its own floristic make-up – is comparatively high. In contrast, in regions with less population but that were settled at a later date, one encounters fewer stands of woody plants with lower numbers of species. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

15.
【目的】为了更好地利用半干旱黄土丘陵区的土地资源,促进该区域植被恢复,提高生物多样性,使区域生态环境有所改善。【方法】以半干旱黄土丘陵区龙滩流域的植被为研究对象,对该流域11种典型的土地利用类型(2种农地、自然荒草地、人工牧草地、撂荒草地、灌木林地、5种乔木林地)的植被物种组成和多样性进行了调查研究。【结果】流域内共调查到种子植物56科166属254种,其中裸子植物门3科7属13种,占流域总科、总属、总种的5.36%、4.22%、5.12%;被子植物门53科159属241种,占流域总科、总属、总种的94.64%、98.78%、94.88%。在被子植物门中,双子叶植物纲有50科134属205种,单子叶植物纲有3科25属36种,两纲物种分别占流域总种数的80.71%和14.17%,占该门物种总种数的85.06%和14.94%。不同土地利用类型植被多样性分析结果表明,物种丰富度表现为农地物种丰富度低,人工牧草地、撂荒草地和灌木柠条林地居中,乔木林地(山杏、山毛桃、油松、侧柏、青杨)和天然荒草地高;物种多样性表现为马铃薯农地的物种多样性低,覆膜农地、人工牧草地、撂荒草地及灌木柠条林地居中,自然荒草地和乔木林地比较高;物种均匀度表现为农地、撂荒草地、人工牧草地及灌木柠条林地的均匀度高,自然荒草地居中,乔木林地低。【结论】不同土地利用方式和植被演替恢复时间差异是产生植被多样性差异的基础,也是该区域植被恢复和物种多样性保护需要考虑的重要要素。  相似文献   

16.
Wood quality data from 33 sites aged between 15 and 18 years old were analysed to determine the effect of prior land use (pasture, cleared grazing land or timber) on wood density, wood stiffness, fibre length and kraft pulp yield. Sampling sites covered 6 different forest areas within the estate. Prior land use (PLU) significantly affected wood stiffness, density and fibre length but not the kraft pulping traits. In contrast, differences were found between different forest areas for the kraft pulping traits plus fibre length but not for stiffness or density.  相似文献   

17.
We observed the influence of five different altitudes and prevailing agro ecosystems on biomass and carbon sequestration potential in Kullu district of Himachal Pradesh, India. The study area had five prevailing land uses viz., agriculture, agro-horticulture, horticulture, silvi-pasture, and forest at four elevations representing about 1 °C temperature change. The results showed that maximum total biomass of 404.35 Mg C ha?1 was accumulated by forest landuse and followed a decreasing trend in the order as forest > silvi-pasture > agro-horticulture > horticulture > agriculture. Similar trends were also seen with respect to biomass carbon (C) density and C-sequestration potential of different land uses. Biomass and carbon density potential enhanced with the increase in the altitudinal ranges from 1100–1400 to 2000–2300 m a.s.l. But, the rate of C-sequestration potential enhanced from 1100 to 2000 m and declined at 2000–2300 m a.s.l. Maximum carbon density (393.29 Mg C ha?1) of both plant as well as soil was displayed by the forest-based land use systems situated at an altitudinal gradient of 2000–2300 m a.s.l. The rate of C-sequestration was maximum (2.17 Mg ha?1) in the agro-horticulture at 2000–2300 m a.s.l. This study brings out the potential of different land use systems influenced by varying factors on their C-sequestration potential in western Himalayan elevation gradient, thereby providing useful information for effective management in a climate change mitigation and carbon budget.  相似文献   

18.
以湖南桑植县石漠化区为研究对象,采用样方调查法对3个不同石漠化等级样地进行植被调查,分析不同石漠化等级植物物种组成结构及植物多样性指数差异,并根据Jaccard群落相似性原理进行不同石漠化等级植物群落间的相似度评价分析.结果表明:调查区共出现草本植物23科39种、木本植物26科38种,优势科为菊科、蔷薇科、百合科、禾本...  相似文献   

19.
20.
The study was conducted with the objective of studying tree species diversity and dominance and the associated changes in soil characteristics in a man-made forest established on formerly barren sodic land at Banthra Research Station (National Botanical Research Institute, Lucknow, India) (80° 45–53E, 26° 40–45N) over three decades. The results revealed that the forest has a moderate value for the tree species diversity index (H). The tree species Derris indica, Dalbergia sissoo, Azadirachta indica, Cassia siamea, Terminalia arjuna, Syzygium cumini, and Tectona grandis were found to be the major dominant species which may be considered suitable for planting on such degraded wastelands. There was a perceptible reduction in soil pH and exchangeable sodium percentage (ESP) and an increase in organic C and Ca2++Mg2+ cation contents over the past three decades, indicating that the sodicity has declined in the surface soil.  相似文献   

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