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Carabid beetles,predatory insects,are abundant in forests and sensitive to environmental changes.The dis-tribution patterns and diversity of carabid beetles in several natural forests were studied to provide a basis for evaluating the importance of a forest in the protection of carabid beetle diversity.Carabids were captured by pitfall traps during their seasonal activity from 2012 to 2013 in a poplar-birch forest,ash-walnut forest and broad-leaved Korean pine forest.A total of 5252 individuals,representing 21 species,were col-lected.Carabid abundance was highest in the broad-leaved Korean pine forest and lowest in the ash-walnut forest.Carabus billbergi Mannerheim and Pterostichus pertinax(Tschitscherine) were the dominant beetle species in each stand.Carabus canaliculatus Adams was dominant in the poplar-birch and ash-walnut forests,and Leistus niger Gebler was dominant in the ash-walnut forest.The carabids were affected differently by stand factors.C.billbergi and P.per-tinax was positively correlated with mean DBH.C.cana-liculatus and L.niger were not positively correlated with any stand factors.The broad-leaved Korean pine forest with greater age,large DBH and thick leaf litter fostered a high diversity of carabid species.The main yearly activity period for most carabids was during July.Different carabid species responded differently to seasonality,and the activity period of several species was relatively late (August) in the year.  相似文献   

3.
The study developed models for predicting the post-fire tree survival in Catalonia. The models are appropriate for forest planning purposes. Two types of models were developed: a stand-level model to predict the degree of damage caused by a forest fire, and tree-level models to predict the probability of a tree to survive a forest fire. The models were based on forest inventory and fire data. The inventory data on forest stands were obtained from the second (1989–1990) and third (2000–2001) Spanish national forest inventories, and the fire data consisted of the perimeters of forest fires larger than 20 ha that occurred in Catalonia between the 2nd and 3rd measurement of the inventory plots. The models were based on easily measurable forest characteristics, and they permit the forest manager to predict the effect of stand structure and species composition on the expected damage. According to the stand level fire damage model, the relative damage decreases when the stand basal area or mean tree diameter increases. Conversely, the relative stand damage increases when there is a large variation in tree size, when the stand is located on a steep slope, and when it is dominated by pine. According to the tree level survival models, trees in stands with a high basal area, a large mean tree size and a small variability in tree diameters have a high survival probability. Large trees in dominant positions have the highest probability of surviving a fire. Another result of the study is the exceptionally good post-fire survival ability of Pinus pinea and Quercus suber.  相似文献   

4.
Voles and shrews are key species in northern forest ecosystems. Thus, it is important to quantify to what extent new forestry practices such as planting of non-native tree species impact these small mammals. In northern Norway stands of coastal subarctic birch forests have increasingly been converted to non-native spruce stands during the last century. This leads to changes in the forest floor vegetation and soil conditions that can be expected to negatively impact the community of ground-dwelling small mammals. In this 10-year trapping study we contrasted seasonal small mammal population abundances in spruce plantations with four birch forest varieties. Six different small mammal species were trapped (in descending order of abundance; common shrew Sorex araneus, red vole Myodes rutilus, field vole Microtus agrestis, grey-sided vole M. rufocanus, pygmy shrew S. minutus and water shrew Neomys fodiens). None of the voles appeared to exhibit temporal dynamics resembling population cycles. The three most numerous species were clearly less abundant in the spruce plantations compared to the other forest types. Autumn abundances were most impacted by spruce plantations, indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats (i.e. field vole and common shrew) were most impacted by tree species conversion. Still young spruce plantations inter-mixed with birch trees and the ecotone habitat, sustained small mammal abundances comparable to the native birch forests. This implies that managing spruce plantations to maintain a mix of different tree species and high spatial heterogeneity (i.e. more ecotones), will reduce the negative impacts on the small mammal community. On the contrary, if young spruce plantations, as they age become spruce monocultures covering larger parts of the landscapes than they do presently, the negative effects on small mammal communities may be larger than observed in the present study.  相似文献   

5.
对惠州市生态公益林的木材薪柴生产、涵养水源、保持水土、保肥效益、净化空气等效益价值进行了估算。结果表明:惠州市生态公益林主要分布于惠东县、博罗县、龙门县,生态效益的总价值为91 609.1万元/年,其中生态功能价值比例达74%。  相似文献   

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Undergrowth clearing is a widespread forest management technique used in many Mediterranean regions to reduce dense vegetation in order to prevent fire or to facilitate other forest exploitation activities. Here, we analyze the effects of undergrowth clearing on biodiversity by focusing on the variations in bird diversity in Holm oak forests in Catalonia (north-east Iberian Peninsula) under different forest management regimes: (1) coppice Holm oak forests where the undergrowth layer has been completely cleared, (2) partially cleared forests and (3) cleared and tree thinned forests and finally, (4) undisturbed forests. The synchronic comparison approach was used in conjunction with a before–after control impact (BACI) experiment in which the effects of undergrowth clearing were explicitly measured. Complete undergrowth clearing resulted in the almost complete disappearance of three Warbler species (Subalpine Warbler, Sardinian Warbler and Garden Warbler). Partial clearing also led to a marked reduction in the numbers of these three species, but the presence of Sardinian and Garden Warblers was maintained in the treated forests. Complete undergrowth clearing accompanied by tree thinning also led to a decrease in amount of undergrowth species and involved additional negative effects for species such as Wren, Robin, Blackbird and Blackcap. Only one species, the Nightjar, appeared to benefit from undergrowth clearing, while many others increased their numbers only when clearing was applied together with tree thinning: Turtle dove, Mistle thrush and Cirl bunting. Undergrowth clearing brought about a significant simplification in the vertical structure of the forest, which probably reduced foraging opportunities and breeding resources for most undergrowth species. These effects became more pronounced when tree thinning was applied together with undergrowth clearing. To reconcile forest management and bird diversity, undergrowth clearing should be applied selectively to ensure that a certain number of undergrowth patches, preferably corresponding to different shrub species, are not affected by management treatments.  相似文献   

8.
We compared the fire regimes in Mediterranean pine forests during two periods, 1370–1466 and 1966–1996 A.D. Medieval fire regime was estimated from the ‘claveria’ books of the Tortosa city, which record the city expenditures, including those for fighting fires that were burning in the city forest. We used the amount spent as an estimate of fire magnitude. Current fire regime was estimated for the same area from the local environment agency data bank, which includes date, location and burned area. The mean number of recorded fires per year, which mostly occurred in summer, is not significantly different between the two periods. Time-since-fire distributions of both periods fitted the negative exponential model, and they were not significantly different. The probability of fire occurring within 1-year interval was 0.44 for the 1379–1466 period and 0.46 for the 1966–1996 period. In both cases, small fires were more abundant, although there are some differences in the medieval series, 13% of all documented fires accounted for 47% of the suppression effort, whereas in the 20th century series, one single fire accounted for 88% of the area burned. Analysis of extreme fire also indicates that in the medieval series the largest fire per year needed one or less days of suppression effort in 58% of the years, whereas in the current period, fires were smaller than 1 ha in 78% of the years. We found that fire suppression in the Middle Ages was associated with forest exploitation. Although we cannot compare the two data sets accurately, there is not evidence of differences in fire frequency between the medieval and the current periods. Differences in fire magnitude distributions of both series of records may be explained by the different purposes and technical resources involved in the fire suppression practices.  相似文献   

9.
If national afforestation targets are met, the proportion of area under plantation forest cover in Ireland will almost double by the year 2030 to 17%, and will consist of mostly non-native trees. There is an urgent and vital need to assess and to maximise the biodiversity potential of these forests. This study compares carabid beetle (Coleoptera, Carabidae) composition and assemblage patterns across different stages of the forest cycle, in addition to intensive grassland habitats, the habitat the plantation forest will most likely be replacing. The clearfell habitat had the highest median species richness, while the grassland habitat had the highest species diversity, but lowest species dominance. Ordination analysis revealed that the species assemblages of all stages of the forest cycle could be clearly separated from the grassland habitat, while differences were also observed between forest stages. Canonical correspondence analysis revealed that the most significant factors influencing carabid community composition were percent cover of ground vegetation and mosses, and also percent soil moisture. Differences in species with varying physical traits and microhabitat preferences were also observed between habitats, with larger, brachypterous species positively associated with increasing canopy cover and smaller macropterous species displaying the opposite pattern. The presence and abundance of forest-associated species increased with increasing plantation age, with a corresponding decrease in open habitat-associated and generalist species. The results of this study suggest that at the landscape scale, a variety of different aged forest stands would maximise the biodiversity potential of the planned afforestation.  相似文献   

10.
  • ? Assessment of forest sustainability requires reliable soil quality indicators. The present study evaluated the use of several potential such indicators in forests in the Basque Country under different types of management, involving: (i) species change and (ii) heavily mechanised forest operations.
  • ? Five adjacent forest stands were selected for study: (i) two unmanaged forests (Quercus robur, Fagus sylvatica) and one (40-year-old) Pinus radiata plantation, to investigate the effect of species change; and (ii) a chronosequence of mechanised radiata pine plantations (3 and 16 years old), to investigate heavy mechanisation.
  • ? Several physical, chemical and biological parameters were analysed in the mineral soil. Species change could not be assessed with chemical parameters, but parameters related to organic matter indicated the disturbance caused by heavy mechanisation. The Least Limiting Water Range was a good indicator of soil physical degradation induced by heavy mechanisation. Biological parameters proved sensitive indicators: (i) the fungal phospholipid fatty acid biomarker 18:2ω6 for species change; and (ii) the ratio of Gram-positive/Gram-negative bacteria for heavy mechanisation. Nevertheless, these parameters are complementary, and monitoring programmes should include physical, chemical and biological parameters.
  • ? Further studies are required to assess natural boundaries of variation in soil quality indicators, and their resistance and resilience.
  •   相似文献   

    11.
    Factors influencing the relationship between ecosystem productivity and biological diversity form the basis of much ecological theory. An understanding of how productivity-diversity relationships are influenced by scale of observation and unique attributes of ecoregions may provide important insights to aid conservation planning for carbon retention and biodiversity. Here we use publically available datasets to investigate patterns of productivity-diversity and explore potential factors influencing these patterns in forests located in five mid-Atlantic and Appalachian states. We used a geographic information system (GIS) to overlay multiple publically available datasets including remotely sensed estimates of productivity from MODIS and tree diversity estimated from the forest inventory analysis (FIA) database. We evaluated productivity-diversity relationships using two scales of observation (among and within ecoregions). We also determined if productivity-diversity relationships might be related to region-wide patterns in land use, and if the relationships varied by forest type, land management zones, and along gradients of mean productivity and diversity. Productivity-diversity relationships depended on scale and varied among ecoregions, and land use was correlated with both productivity and diversity. Mountainous ecoregions were characterized by positive productivity-diversity relationships, whereas coastal ecoregions were characterized by negative productivity-diversity relationships. Forest types and management zones that were on average less productive and more diverse exhibited positive productivity-diversity relationships across stands (the most productive stands were more diverse). In contrast, ecoregions and forest types that were on average more productive and less diverse exhibited negative productivity-diversity relationships (the most productive stands were less diverse). In conclusion, regional and local ecological and anthropogenic factors likely influence productivity-diversity relationships and these relationships appear to change along gradients of productivity and diversity.  相似文献   

    12.
    Recurrence of recent large wildfires is threatening the permanence of Pinus nigra Arnold (Black pine) forests in central Catalonia (NE Spain), due to the almost nil post-fire regeneration of this non-serotinous pine. Potential practices to carry out extensive reforestation programs with P. nigra may differ widely in terms of their final success, economic cost and undesired ecological impact. In this framework, we have analysed different types of vegetation clearing (mechanical, controlled burning or grazing), soil preparation (ripping or planting holes) and reforestation methods (broadcast seeding, spot seeding and planting) to restore P. nigra forests. We have compared these practices in terms of seedling establishment, but also in the light of their economic costs and ecological impact, through a new multi-criteria analysis. Seedling establishment after sowing was very poor and not influenced by vegetation clearing. In plantations, seedling survival was higher in the ripper treatment than in planting holes for all vegetation clearing treatments except the control one. Nevertheless, the higher economic cost of the planting holes treatment and the negative impact of mechanical clearing and burning on the small mammals community made the stated differences in seedling survival irrelevant. Thus, the multi-criteria analysis revealed that the two most preferred options were planting in uncleared or lightly grazed areas with soil preparation through ripping. This study gives some valuable insights about the use of new decision-support tools in restoration programs and provides practical guidelines concerning the restoration of extensive burned P. nigra forests.  相似文献   

    13.
    Activities associated with timber harvesting have occurred within floodplain forests in the southern United States for nearly two hundred years. However, it is only in the last ten years that any information has become available about the effects of harvesting on the ecological functions of this valuable resource. Hydrology is the driving influence behind all ecological processes in floodplains, and timber harvesting alone usually has little long-term effect on hydroperiod. However, logging roads, built in association with harvest sites, can sometimes alter hydroperiod to the extent that vegetation productivity is raised or lowered. There is no evidence that harvesting followed by natural regeneration represents a threat to ground or surface water quality on flood plain sites, as long as “best management practices” are followed. Harvested floodplains may increase or have little effect on decomposition rates of surface organic matter. The nature of the effect seems to be controlled by site wetness. Data from recently harvested sites (i.e. within the last ten years) suggest that vegetation productivity is maintained at levels similar to those observed prior to harvests. During the early stages of stand development, tree species composition is heavily influenced by harvest method. Similarly, amphibian populations (monitored as bioindicators of ecosystem recovery) seem to rebound rapidly following harvests, although species composition may be different from that of unharvested stands.  相似文献   

    14.
    Although Zagros forests in western Iran lack industrial timber value due to the severe climate and socioeconomics problems, non-timber products are of great value and importance due to their high economic potential and also their potential to improve the welfare of forest-dwelling and forest-fringe villagers. This study was done in the forests of the Zemkan basin, an important part of central Zagros forests, Iran, to recognize the non-timber forest products (NTFPS), investigate their potential economic value and role in people’s livelihood. Data, collected using forest cruising, participatory observations, interviews with indigenous and local persons and experts, identified wild pistachio resin, wild pistachio fruit, oak fruit and oak syrup (Shokeh manna) among the non-timber products in this basin with total potential harvestable NTFPs of 77.16, 771.602, 13248.68, and 1324.868 tons per year, respectively. The economic rent from NTFPs is 33 US$/ha/year and its total expected values with consideration of real interest rate when the exploiter invests the capital in the bank (6.4 %) and when money is borrowed from the bank to execute the incorporated projects (8.4 %) are $516/ha and $393/ha, respectively. Furthermore, families’ economic share from potential profit of NTFPs is annually $601 per household. In addition wild pistachio resin has the highest share of the total potential profit of NTFPs and its equal to 51 % of the total of potential profit of NTFPs. Therefore, it is suggested that decisions be made to increase the infrastructure and strengthen the local selling market to enhance the cash income from NTFPs. Forest participatory management practices are suggested to organize and improve traditional use of the forests.  相似文献   

    15.
    黑龙江省的栎林种类主要有蒙古栎林、辽东栎林、槲栎林、栓皮栎林和槲树。其中,蒙古栎林又包括杜鹃蒙古栎林、胡枝子蒙古栎林和榛子蒙古栎林。它们的分布情况、群落结构、生态习性等各有特点。  相似文献   

    16.
    Norway spruce trees in the subalpine forests of the European Alps are frequently attacked by the needle rust Chrysomyxa rhododendri. The obligate parasite undergoes a complex life cycle with a host shift between rhododendrons (Rhododendron sp.) and Norway spruce [Picea abies (L.) Karsten] and causes a yellowing and defoliation of the current-year needles in summer. Infected trees show several anatomical, morphological and physiological modifications, including a decrease in pigment content and net photosynthesis of infected needles, lower biomass production and reduced radial and height growth. The consequences are diminished timber yield and cripple growth. Because of repeated heavy infections in recent years, forest managers report increasing difficulties in both natural regeneration and afforestation at high elevation sites, where rhododendrons occur. This review gives a summary of the present knowledge about the effects of C. rhododendri infections on Norway spruce, including so far unpublished findings and with particular attention to the phenomena of resistant trees. Implications for subalpine forests and counter strategies are discussed.  相似文献   

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    This study investigates the effects of increasing soil penetration resistance(SPR) on seedling morphology and seedling architecture. When seedlings of deciduous Cappadocian maple(Acer cappadocicum Gled.) were grown in a greenhouse in a loamy soil under a wide range of soil compactions, all morphological variables studied changed significantly with increasing SPR. The relationships between increasing SPR and all morphological responses except lateral root length followed a negative quadratic curve. All biomass variables except lateral root biomass showed a bell-shaped response with respect to SPR, with a maximum biomass variable between 0.6 and1.2 MPa, decreasing at higher soil compaction values. All allocation ratios were significantly affected by soil penetration resistance. Biomass allocation to roots was also affected by soil compaction. There was not a significant relationship between the specific stem length and increasing soil penetration resistance. The specific root length showed two trends to increasing SPR; it first decreased in response to the moderate compaction treatment(up to about 1.2 MPa), then increased significantly. We concluded that increasing soil compaction caused morphological changes to root and shoot sections of A.cappadocicum seedlings.  相似文献   

    19.
    广州城市绿地植物群落生态效应分析   总被引:5,自引:1,他引:5  
    对广州城市绿地中不同植物群落的生态效应进行对比分析和研究,探讨了不同的绿地群落在物种丰富度、三维绿量、空气质量改善、降温增湿等方面的差异及原因,指出叶面积指数在绿地生态结构与生态功能方面起着关键指标的作用,以期为城市绿地的生态建设提供相关依据。  相似文献   

    20.
    易门县2005、2009年先后启动实施国家级和省级公益林生态项目建设,针对项目实施以来公益林管护中存在的问题进行分析,藉此提出相应对策、建议。  相似文献   

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