logging

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  • 文章类型: Journal Article
    在森林生态系统中,茎呼吸占自养呼吸的很大一部分。但是它在不同空间尺度和土地利用梯度上的驱动因素仍然知之甚少。这项研究量化并检查了伐木干扰对马来西亚婆罗洲茎CO2排放(EA)的影响。使用静态室方法,在从大量记录到旧生长的记录梯度上,在9个1公顷地块的树木和林分水平上对EA进行了量化。树木水平的结果显示,在伐木和旧生长的地块中,每单位茎面积的EA较高(37.0±1.1vs26.92±1.14gCm-2month-1)。然而,在立场上,由于老生长地块的茎表面积更大,伐木和老生长地块之间的EA没有差异(6.7±1.1vs6.0±0.7MgCha-1yr-1)。在伐木地块中,生长呼吸和碳利用效率的分配明显更高。树木和林分水平的EA变化是由树木大小驱动的,森林类型之间的增长和投资策略的差异。这些结果反映了不同的资源分配策略和优先事项,优先考虑增长,以应对伐木地块中光照的增加,而旧增长地块优先考虑维护和单元结构。
    Stem respiration constitutes a substantial proportion of autotrophic respiration in forested ecosystems, but its drivers across different spatial scales and land-use gradients remain poorly understood. This study quantifies and examines the impact of logging disturbance on stem CO2 efflux (EA) in Malaysian Borneo. EA was quantified at tree- and stand-level in nine 1-ha plots over a logging gradient from heavily logged to old-growth using the static chamber method. Tree-level results showed higher EA per unit stem area in logged vs old-growth plots (37.0 ± 1.1 vs 26.92 ± 1.14 g C m-2 month-1). However, at stand-level, there was no difference in EA between logged and old-growth plots (6.7 ± 1.1 vs 6.0 ± 0.7 Mg C ha-1 yr-1) due to greater stem surface area in old-growth plots. Allocation to growth respiration and carbon use efficiency was significantly higher in logged plots. Variation in EA at both tree- and stand-level was driven by tree size, growth and differences in investment strategies between the forest types. These results reflect different resource allocation strategies and priorities, with a priority for growth in response to increased light availability in logged plots, while old-growth plots prioritise maintenance and cell structure.
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  • 文章类型: Journal Article
    河流发电厂(ROR)代表了全球大多数水力发电厂。它们对环境的影响没有充分的记录,据信是有限的,特别是关于甲基汞(MeHg)对食物网的污染,一种神经毒素.ROR通常安装在小河流中,流域干扰与大坝建设的综合影响会使环境管理复杂化。我们报告了一项关于圣莫里斯河(加拿大)的多年案例研究,在建造了两个ROR植物后,观察到捕食者鱼中甲基汞积累的暂时增加。相关的池塘充当了受森林大火和伐木干扰的流域中汞(Hg)和有机物的沉积盆地。这种新鲜的有机碳可能推动了微生物甲基汞的生产。与汞的存在相比,汞甲基化与环境条件更相关,并鉴定了主要的甲基化微生物群。人工湿地是汞甲基化的重要部位,但不是鱼类汞增加的主要来源。有机碳降解是食物链底部甲基汞积累的主要驱动因素,而营养水平解释了食物链顶部的变化。总的来说,碳循环是该系统中汞动力学的关键驱动因素,和ROR植物可能会导致暂时的(大约12年)在受干扰的流域发展时,食物网中的汞增加,尽管这一增幅小于大型水库。未来ROR建设的建议是建立具有初始高时间分辨率的良好环境监测计划,并在计划中考虑近期和潜在的流域干扰。
    Run-of-river power plants (ROR) represent the majority of hydroelectric plants worldwide. Their environmental impacts are not well documented and are believed to be limited, particularly regarding the contamination of food webs by methylmercury (MeHg), a neurotoxin. RORs are typically installed in small rivers where combined effects of watershed disturbances with dam construction can complicate environmental management. We report a multi-year case study on the Saint-Maurice River (Canada) where an unpredicted temporary increase in MeHg accumulation in predator fish was observed after the construction of two ROR plants. The associated pondages acted as sedimentation basins for mercury (Hg) and organic matter from a watershed disturbed by a forest fire and by logging. This fresh organic carbon likely fueled microbial MeHg production. Hg methylation was more associated with environmental conditions than to the presence of Hg, and main methylating microbial groups were identified. A constructed wetland was a site of significant Hg methylation but was not the main source of the fish Hg increase. Organic carbon degradation was the main driver of MeHg accumulation at the base of the food chain whereas trophic levels explained the variations at the top of the food chain. Overall, carbon cycling was a key driver of Hg dynamics in this system, and ROR plants can cause temporary (ca. 12 years) Hg increase in food webs when developed in disturbed watersheds, although this increase is smaller than for large reservoirs. Recommendations for future ROR construction are to establish a good environmental monitoring plan with initial high temporal resolution and to consider recent and potential watershed disturbances in the plan.
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  • 文章类型: Journal Article
    了解初级生产力和多样性如何影响次级生产力是生态学中的重要辩论,对生物多样性保护具有重要意义。特别是,植物多样性如何影响节肢动物多样性有助于我们对营养级联和物种共存的理解。先前的研究表明,植物与节肢动物多样性之间存在正相关。关联抗性理论表明,植物的食草率会随着植物多样性的增加而降低,这表明主要多样性之间的反馈。生产力,和二级生产率。然而,我们对这些关系如何由人为干扰介导的理解仍然有限.我们调查了10个森林遗址,其中一半受到火灾的干扰,测井,和树修剪,分布在贝宁的两个气候带,西非。我们建立了100个样带来记录植物物种,并使用陷阱陷阱对节肢动物进行采样,带诱饵的陶瓷板,和扫网。我们开发了一个结构方程模型来测试慢性人为干扰对植物多样性的中介作用以及它如何影响节肢动物的多样性和丰度。节肢动物多样性增加,但节肢动物丰度随干扰强度的增加而降低。我们发现植物多样性对节肢动物多样性没有显着的自下而上的影响,但植物多样性与节肢动物丰度之间存在显着的关系。一些节肢动物行会受到植物多样性的显着影响。最后,食草率与节肢动物多样性呈正相关。综合。我们的结果强调了慢性人为干扰如何在多样性和生产力方面介导营养水平之间的功能联系。我们的研究证明了节肢动物多样性和丰富度对干扰的解耦响应。我们在研究中发现,植物多样性对草食率的直接积极影响为关联抗性理论提供了反支持。
    Understanding how primary productivity and diversity affect secondary productivity is an important debate in ecology with implications for biodiversity conservation. Particularly, how plant diversity influences arthropod diversity contributes to our understanding of trophic cascades and species coexistence. Previous studies show a positive correlation between plant and arthropod diversity. The theory of associational resistance suggests that plant herbivory rate will decrease with increasing plant diversity indicating feedbacks between primary diversity, productivity, and secondary productivity rates. However, our understanding of how these relations are mediated by anthropogenic disturbance is still limited. We surveyed 10 forest sites, half of which are disturbed by fire, logging, and tree pruning, distributed in two climatic zones in Benin, West Africa. We established 100 transects to record plant species and sampled arthropods using pitfall traps, ceramic plates with bait, and sweeping nets. We developed a structural equation model to test the mediating effect of chronic anthropogenic disturbance on plant diversity and how it influences arthropod diversity and abundance. Arthropod diversity increased but arthropod abundance decreased with increasing intensity of disturbance. We found no significant bottom-up influence of the plant diversity on arthropod diversity but a significant plant diversity-arthropod abundance relationship. Some arthropod guilds were significantly affected by plant diversity. Finally, herbivory rates were positively associated with arthropod diversity. Synthesis. Our results highlight how chronic anthropogenic disturbance can mediate the functional links between trophic levels in terms of diversity and productivity. Our study demonstrated a decoupled response of arthropod diversity and abundance to disturbance. The direct positive influence of plant diversity on herbivory rates we found in our study provides counter-support for the theory of associational resistance.
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  • 文章类型: Journal Article
    爬行动物是一个重要的,但经常被研究不足,自然保护中的分类单元。它们在生态系统中起着重要的作用1,可以作为环境健康的指标,通常比其他脊椎动物对人类压力的反应更快。2目前,至少有21%的爬行动物被评估为濒临灭绝的威胁。由于直到最近还缺乏全面的全球评估,在解决保护或空间优先次序的空间研究中省略了它们(例如,Rosauer等人。,4,5,6,7,8弗里茨和拉贝克,4,5,6,7,8Farooq等人。,4,5,6,7,8Meyer等人。,4,5,6,7,8和Farooq等4,5,6,7,8)。保护方面的一个重要知识差距是缺乏关于生物多样性主要威胁的空间明确信息,9,这显著阻碍了我们有效应对当前生物多样性危机的能力。10,11在这项研究中,我们计算了特定位置的爬行动物物种受到七种生物多样性威胁之一-农业影响的概率,气候变化,狩猎,入侵物种,测井,污染,和城市化。我们在全球范围内进行了分析,使用50公里×50公里的网格,并通过研究它们与灭绝风险的关系来评估这些威胁的影响。我们发现气候变化,测井,污染,入侵物种与灭绝风险联系最大。然而,我们还表明,这些结果存在相当大的地理差异。我们的研究强调了超越衡量威胁强度的重要性,以衡量这些威胁对世界各个生物地理区域的影响。在不同的历史偶然性下,而不是单一的全球分析对待所有地区都一样。
    Reptiles are an important, yet often understudied, taxon in nature conservation. They play a significant role in ecosystems1 and can serve as indicators of environmental health, often responding more rapidly to human pressures than other vertebrate groups.2 At least 21% of reptiles are currently assessed as threatened with extinction by the IUCN.3 However, due to the lack of comprehensive global assessments until recently, they have been omitted from spatial studies addressing conservation or spatial prioritization (e.g., Rosauer et al.,4,5,6,7,8 Fritz and Rahbek,4,5,6,7,8 Farooq et al.,4,5,6,7,8 Meyer et al., 4,5,6,7,8 and Farooq et al.4,5,6,7,8). One important knowledge gap in conservation is the lack of spatially explicit information on the main threats to biodiversity,9 which significantly hampers our ability to respond effectively to the current biodiversity crisis.10,11 In this study, we calculate the probability of a reptile species in a specific location being affected by one of seven biodiversity threats-agriculture, climate change, hunting, invasive species, logging, pollution, and urbanization. We conducted the analysis at a global scale, using a 50 km × 50 km grid, and evaluated the impact of these threats by studying their relationship with the risk of extinction. We find that climate change, logging, pollution, and invasive species are most linked to extinction risk. However, we also show that there is considerable geographical variation in these results. Our study highlights the importance of going beyond measuring the intensity of threats to measuring the impact of these separately for various biogeographical regions of the world, with different historical contingencies, as opposed to a single global analysis treating all regions the same.
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  • 文章类型: Journal Article
    北方景观面临越来越多的干扰,可能会影响文化基石物种,即文化上突出的物种,以主要方式塑造一个民族的文化身份。鉴于其重要性,应该评估这些物种的命运,以便能够采取行动确保它们的持久性。我们评估了气候变化和森林采伐将如何影响杜鹃花和杜鹃花的栖息地质量,加拿大东部许多土著人民的两种文化基石。我们使用森林景观模型LANDIS-II结合物种分布模型,根据不同的气候变化和森林采伐情景,模拟了这两个物种在三个土著社区领土上的栖息地质量。气候敏感参数包括野火制度以及树木生长。适度的气候变化情景与景观中的绿叶菌和绿叶弧菌的比例增加有关,后一种物种也对严重的气候变化情景做出积极反应。收割效果甚微,但略微降低了两种物种存在的可能性。根据建模结果,在温和的气候变化情景下,这两种物种都没有风险。然而,在严重的气候变化下,roenlandicum可能会随着落叶乔木在景观中的比例增加而下降。缓解气候变化战略,如规定的火灾,可能有必要限制这种增加。这将防止根瘤的减少,并有助于保护生物多样性和可收获量。
    Boreal landscapes face increasing disturbances which can affect cultural keystone species, i.e. culturally salient species that shape in a major way the cultural identity of a people. Given their importance, the fate of such species should be assessed to be able to act to ensure their perennity. We assessed how climate change and forest harvesting will affect the habitat quality of Rhododendron groenlandicum and Vaccinium angustifolium, two cultural keystone species for many Indigenous peoples in eastern Canada. We used the forest landscape model LANDIS-II in combination with species distribution models to simulate the habitat quality of these two species on the territories of three Indigenous communities according to different climate change and forest harvesting scenarios. Climate-sensitive parameters included wildfire regimes as well as tree growth. Moderate climate change scenarios were associated with an increased proportion of R. groenlandicum and V. angustifolium in the landscape, the latter species also responding positively to severe climate change scenarios. Harvesting had a minimal effect, but slightly decreased the probability of presence of both species where it occurred. According to the modeling results, neither species is at risk under moderate climate change scenarios. However, under severe climate change, R. groenlandicum could decline as the proportion of deciduous trees would increase in the landscape. Climate change mitigation strategies, such as prescribed fires, may be necessary to limit this increase. This would prevent the decrease of R. groenlandicum, as well as contribute to preserve biodiversity and harvestable volumes.
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  • 文章类型: Journal Article
    树木作业和与拖拉机有关的活动造成的伤害和死亡事件导致农业和伐木部门与工作有关的伤害率已经上升。这份简短的报告强调了围绕这些事件的情况,以及一些监测来源,以确定它们在这些危险行业中造成伤害负担的程度。这些数据来源包括死亡调查,农业伤害新闻报道,从急诊室获取的消费品伤害数据和从参加国家翻滚保护结构回扣计划(NRRP)的个人获取的未遂报告数据。概述了进一步研究和干预工作的一些建议,特别考虑到滚柱在坠落物体事故中的参与方式。
    Injury and fatality events that are caused by tree work and tractor-related activities contribute to the already elevated rates of work-related injuries in the agriculture and logging sectors. This brief report highlights the circumstances surrounding these events, as well as a number of surveillance sources that identify the extent to which they contribute to the injury burden in these hazardous industries. These data sources include fatality investigations, agricultural injury news reports, consumer product injury data captured from emergency rooms and near-miss reporting data captured from individuals participating in the National Rollover Protective Structure Rebate Program (NRRP). Several recommendations for further research and interventional efforts are outlined, with particular consideration of the manner in which rollbars have been involved in falling object incidents.
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  • 文章类型: Journal Article
    全球许多森林类型的频率都在增加,和被烧毁的区域,严重的野火.在这里,我们探讨了先前的干扰在增加后续森林火灾的范围和严重程度中所起的作用。Wesummariseevidencedocumentingandexplainingthemechanismsunderpunderingapulseofflammabilitythatmayfollowingdisturrantssuchasfire,测井,清除或排风(我们称之为干扰刺激的可燃性的过程)。扰动有时会引发短暂的低可燃性初始阶段,但是随着植被的重新生长,可燃性延长了一段时间。我们的分析最初集中在澳大利亚有据可查的案例,但是我们也讨论了这些模式可能适用于其他地方,包括在北半球。我们概述了干扰通过破坏在未受干扰的森林中限制其的生态控制来驱动可燃性的机制。然后,我们开发并测试了一个概念模型,以帮助预测可能发生这种干扰刺激的可燃性模式的木本植被群落。我们讨论了生态控制与气候变化的相互作用,正在引发更大更严重的火灾。我们还探索了当前的知识状态,容易起火的林分在景观中足够广泛,以至于它们可能会促进高严重性野火的空间传染,从而压倒了易燃性较低的林分所提供的火灾蔓延的任何减少。我们讨论了土地管理者如何应对景观覆盖变化和火灾状况改变可能带来的主要挑战。这在现在以伐木后大量年轻森林再生为主导的景观中尤其重要,在包括规定燃烧在内的大规模火灾后再生,或在放弃农业用地后再生。当发现干扰刺激可燃性时,然后,关键的管理行动应考虑以下方面的长期利益:(i)限制基于干扰的管理,例如伐木或燃烧,这会产生年轻的森林并引发林下的发展;(ii)保护年轻的森林免受干扰,并帮助它们过渡到较老的森林,不太易燃的状态;和(Iii)增强老年人的防火性能,通过快速火灾探测和灭火的方法,易燃性较低。
    Many forest types globally have been subject to an increase in the frequency of, and area burnt by, high-severity wildfire. Here we explore the role that previous disturbance has played in increasing the extent and severity of subsequent forest fires. We summarise evidence documenting and explaining the mechanisms underpinning a pulse of flammability that may follow disturbances such as fire, logging, clearing or windthrow (a process we term disturbance-stimulated flammability). Disturbance sometimes initiates a short initial period of low flammability, but then drives an extended period of increased flammability as vegetation regrows. Our analysis initially focuses on well-documented cases in Australia, but we also discuss where these pattens may apply elsewhere, including in the Northern Hemisphere. We outline the mechanisms by which disturbance drives flammability through disrupting the ecological controls that limit it in undisturbed forests. We then develop and test a conceptual model to aid prediction of woody vegetation communities where such patterns of disturbance-stimulated flammability may occur. We discuss the interaction of ecological controls with climate change, which is driving larger and more severe fires. We also explore the current state of knowledge around the point where disturbed, fire-prone stands are sufficiently widespread in landscapes that they may promote spatial contagion of high-severity wildfire that overwhelms any reduction in fire spread offered by less-flammable stands. We discuss how land managers might deal with the major challenges that changes in landscape cover and altered fire regimes may have created. This is especially pertinent in landscapes now dominated by extensive areas of young forest regenerating after logging, regrowing following broadscale fire including prescribed burning, or regenerating following agricultural land abandonment. Where disturbance is found to stimulate flammability, then key management actions should consider the long-term benefits of: (i) limiting disturbance-based management like logging or burning that creates young forests and triggers understorey development; (ii) protecting young forests from disturbances and assisting them to transition to an older, less-flammable state; and (iii) reinforcing the fire-inhibitory properties of older, less-flammable stands through methods for rapid fire detection and suppression.
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  • 文章类型: Journal Article
    这项研究的目的是为蒙大拿州的专业伐木工人开发和评估有针对性的紧急急救和安全培训计划。该计划有两个关键目标:(1)参与者对关键概念的召回和保留的演示;(2)与上一年的培训计划相比,改善了参与者的接受度。培训的系统方法为培训计划的开发和实施提供了总体模型。定性和定量分析用于评估培训计划的有效性。培训计划对873名伐木者进行了管理。Pre-,post-,后续考试用于评估关键学习目标的召回和保留情况,而调查用于评估学习者对更新培训计划的接受程度。培训后调查数据表明培训适用性增加,学习目标的理解,与上一年的培训计划相比,更新计划的整体课程享受。参与者在培训后考试中得分明显更高,这表明了对关键培训目标的回忆。培训评估获得的结果将指导未来的研究和培训计划的持续发展,以符合正在进行的分析活动和参与者的建议。
    The purpose of this research was to develop and assess a targeted emergency first-aid and safety training program for professional loggers in Montana. There were two key objectives for the program: (1) participant demonstration of recall and retention of key concepts and (2) improved participant reception in comparison to the previous year\'s training program. The Systematic Approach to Training provided the overall model for the development and conduct of the training program. Qualitative and quantitative analyses were used to assess the effectiveness of the training program. The training program was administered to 873 loggers. Pre-, post-, and follow-up examinations were used to assess recall and retention of key learning objectives, while surveys were used to assess learner reception of the updated training program. Post-training survey data indicated increases in training applicability, understanding of learning objectives, and overall course enjoyment of the updated program in comparison to the previous year\'s training program. Participants scored significantly higher on the post-training exams, which demonstrated recall of key training objectives. The results obtained by the training evaluation will guide future research and the continued development of the training program to align with ongoing analysis activities and participant suggestions.
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  • 文章类型: Journal Article
    背景:尽管安全性得到了显着改善,伐木仍然是美国最危险的行业之一。这项研究的目的是探索缅因州伐木工人的纵向伤害趋势。
    方法:伐木工人参加了七个季度调查,在18个月的过程中。与创伤性和急性损伤相关的分类和自由文本数据,肌肉骨骼疾病(MSD),慢性疼痛从REDCap导出到SAS9.4,Excel,还有NVivo,用于定量和定性分析,分别。使用两种不同的方法对损伤时间进行建模:(1)通过比例风险回归建模的首次损伤发生时间和(2)损伤频率的强度模型。两名研究小组成员还使用内容分析方法分析了定性数据。
    结果:在研究期间,报告有204人受伤。在154名参与者中,93(60.4%)在至少一项调查中报告了肌肉骨骼疼痛。大部分受伤是创伤性的,包括骨折,扭伤,和菌株。发现缺乏健康保险与首次受伤风险增加有关[HR=1.41,95%CI=0.97-2.04,p=0.069]。在单变量水平发现与损伤强度相关的变量是:(1)缺乏健康保险[HR=1.51,95%CI=1.04-2.20,p=0.030],(2)年龄[10岁增加的HR;=1.12,95%CI=0.99-1.27,p=0.082],和(3)伐木业雇用年限[10年增长的HR=1.12,95%CI=0.99-1.26,p=0.052]。对于这个队列来说,寻求受伤的医疗护理并不是一个优先事项,叙述揭示了自我评估的趋势。各种各样的障碍,包括金融,阻止伐木工人寻求医疗救助。
    结论:我们发现伐木工人仍然经历严重的,有时会致残,与工作有关的伤害。许多受伤是由于滑倒造成的,这并不令人惊讶,trips,和瀑布,以及与伐木设备和树木/原木的联系。这些叙述揭示了各种障碍,阻止伐木工人实现最佳健康。例子包括与医疗保健的地理距离,缺乏时间来获得护理,和根深蒂固的价值观,优先考虑独立和传统的男子气概。财务考虑也一直被认为是获得适当护理的主要障碍。
    结论:在伐木工业中仍然需要强调职业健康和安全。实施相关安全方案是关键,但是,在这个行业发生文化转变之前,这些好处很可能不会完全实现。
    Despite dramatic improvements in safety, logging remains one of the most dangerous industries in the United States. The purpose of this study was to explore longitudinal injury trends among Maine logging workers.
    Loggers participated in seven quarterly surveys, over the course of 18 months. Categorical and free text data related to traumatic and acute injury, musculoskeletal disorders (MSD), and chronic pain were exported from REDCap into SAS 9.4, Excel, and NVivo, for quantitative and qualitative analysis, respectively. Time to injury was modeled using two different approaches: (1) time to the occurrence of first injury modeled by proportional hazard regression and (2) an intensity model for injury frequency. Two research team members also analyzed qualitative data using a content analysis approach.
    During the study, 204 injuries were reported. Of the 154 participants, 93 (60.4%) reported musculoskeletal pain on at least one survey. The majority of injuries were traumatic, including fractures, sprains, and strains. Lack of health insurance was found to be related to increased risk of first injury [HR = 1.41, 95% CI = 0.97-2.04, p = 0.069]. Variables found to be related to injury intensity at the univariate level were: (1) a lack of health insurance [HR = 1.51, 95% CI = 1.04-2.20, p = 0.030], (2) age [HR for 10-year age increase;= 1.12, 95% CI = 0.99-1.27, p = 0.082], and (3) years employed in logging industry [HR for 10-year increase = 1.12, 95% CI = 0.99-1.26, p = 0.052]. Seeking medical attention for injury was not a priority for this cohort, and narratives revealed a trend for self-assessment. A variety of barriers, including finances, prevented loggers from seeking medical attention.
    We found that loggers still experience serious, and sometimes disabling, injuries associated with their work. It was unsurprising that many injuries were due to slips, trips, and falls, along with contact with logging equipment and trees/logs. The narratives revealed various obstacles preventing loggers from achieving optimal health. Examples included geographic distance from healthcare, lack of time to access care, and entrenched values that prioritized independence and traditional masculinity. Financial considerations were also consistently cited as a primary barrier to adequate care.
    There is a continued need to emphasize occupational health and safety in the logging industry. Implementation of relevant safety programs is key, but it is likely that the benefits of these will not be fully realized until a cultural shift takes place within this industry.
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  • 文章类型: Journal Article
    温带森林的初级生产力通常受到氮(N)供应的限制,树木的清除可能会加剧这种情况。选择性记录后,是否以及在恢复过程中通过迅速增加的养分周转来缓解N限制的机制,这对改善温带森林的碳固存很重要,仍然不清楚。我们通过选择28个林地,包括7个森林恢复期(在6、14、25、36、45、55和100年前),通过测量土壤N浓度进行低强度选择性测井(13-14m3/ha)和一次未采伐处理,研究了养分限制(群落水平的叶片N:P比)对植物群落生产力的影响。土壤磷(P)浓度,叶片N浓度,叶片P浓度,和234种植物的地上净初级生产力(ANPP)。温带森林的植物生长受到氮素的限制,但是在36年前记录的地点观察到了P限制,这表明在森林恢复过程中植物生长从N限制到P限制的过渡模式。同时,随着群落叶片氮磷比的增加,观察到群落ANPP的稳健线性趋势,这表明选择性测井后随着N限制的释放,群落ANPP的增强。养分限制(叶N:Pcom)对群落ANPP有显著的直接影响(56.0%),对群落ANPP变异的独立贡献(25.6%)高于土壤养分供应,甚至物种丰富度的变化。我们的结果表明,选择性测井减轻了氮的限制,但是,在学习恢复过程中碳固存的变化时,也应高度重视向P限制的转变。
    The primary productivity of temperate forests is commonly limited by nitrogen (N) supply, which may be aggravated by the removal of trees. After selective logging, whether and the mechanism by which the N limitation can be alleviated by the rapidly increasing nutrient turnover during the recovery processes, which is important for improving carbon sequestration in temperate forests, remain unclear. We investigated the effect of nutrient limitation (leaf N:Pcom: the leaf N:P ratio at the community level) on plant community productivity by selecting 28 forest plots including seven forest recovery periods (at the sites logged 6, 14, 25, 36, 45, 55, and 100 years ago) following low-intensity selective logging (13-14 m3/ha) and one unlogged treatment by measuring the soil N concentration, soil phosphorus (P) concentration, leaf N concentration, leaf P concentration, and the aboveground net primary productivity (ANPP) of 234 plant species. The plant growth in temperate forests was limited by N, but the P limitation was observed at the sites logged 36 years ago, which showed a transition pattern of plant growth from N limitation to P limitation during the forest recovery process. Meanwhile, a robust linear trend in the community ANPP was observed with the increase in the community leaf N:P ratio, which suggests the enhancement in community ANPP with the release of N limitation after selective logging. Nutrient limitation (leaf N:Pcom) had a significant direct effect (56.0 %) on the community ANPP and showed a higher independent contribution (25.6 %) to the variation in the community ANPP than the soil nutrient supply and even the changes in species richness. Our results suggested that selective logging alleviated the N limitation, but a shift toward P limitation should also be highly regarded in learning the changes in carbon sequestration during the recovery processes.
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