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1.
To restore the human-disturbed natural ecology and to assess the impact of the projected future climatic change on the natural ecology at a plant community level or at a plant species level, we need to understand the potential distribution of the community or the species under current climate conditions. Many methods have recently been developed to simulate the potential distribution of a particular community or a particular species, but very little has been done to assess the potential distribution of Qinghai spruce (Picea crassifolia) in Qilian Mountains where the spruce forests are extremely important ecologically and hydrologically. This study used maximum entropy model to simulate the potential distribution of Qinghai spruce under current climate conditions and the validity of the model was verified by statistically comparing the simulated potential distribution with the observed actual distribution of the spruce. We then applied this verified model to assess the impact of the projected future climatic changes on the spruce and the simulated results show that the areal extent of the potential distribution of Qinghai spruce may increase by 1% under the projected future climate change scenario. In addition, this study revealed that among the 19 environmental and climatic factors used in this model, the most important factors are the mean maximum temperature in the warmest month and the mean temperature of the wettest quarter in controlling the potential distribution of Qinghai spruce, these two factors accounting for as much as 75.6% of the variations. 相似文献
2.
青海云杉是祁连山森林生态系统的主要建群种,具有重要的生态水文功能.冠层盖度是评估生态环境的一个重要参数, 但目前缺乏有效评估手段.半球摄影技术在估算林冠盖度方面已显示出潜在优势,但它受到环境条件例如天气的影响仍然没有报道.在祁连山排露沟流域利用半球摄影技术反演冠层盖度,界定不同天气条件对阈值的影响,评估与传统方法估算林冠盖度的差别,结果表明:分类阈值受天气状况的影响较大,阴天的最佳阈值为118,晴天的最佳阈值为149;另外传统观测与半球图像法获得的林冠盖度有一定的差异,其中最大差值17.88%,最小差值5.34%.该项研究对青海云杉林盖度估算提供新的方法,为生态水文过程模型提供有价值的输入参数. 相似文献
3.
The evergreen coniferous creeping shrub, Sabina vulgaris, is widely distributed in China, from high and cold mountain sites to low-elevation arid desert areas. This paper performed dendroclimatological analysis of the samples of S. vulgaris from three sampling sites (2700–2900 m a.s.l.) at sites in the northern border of the middle Qilian Mountains, Northwest China. We found that the radial growth of S. vulgaris was mainly limited by rainfall during the growing season, especially in May and June, but was also limited by low temperatures in the late growing season. It presents the regional differention of the climate response of the shrub radial growth from the other distributed areas, such as the sandland and mountains. We constructed a 274-year drought record by calibrating growth-ring data and relating this data to the regional monthly Palmer Drought Severity Index (PDSI56), which represents regional moisture conditions. The PDSI56 reconstruction accounted for 35.5 % of the variation of the actual May to June PDSI56 during the period for which meteorological data was available (1950–2014). The most severe drought occurred during the 1920s, followed by the 1950s, 1740s, and the period from the 1870s to the 1880s; the wettest years were during the 1980s, followed by the 2010s, 1770s, and 1750. The changes between drought, normal, and wet periods were consistent with the reconstructed results from previous conifer ring series for Sabina przewalskii and Picea crassifolia in the study area. Our results demonstrate the value of S. vulgaris in dendrochronology. 相似文献
4.
深入探讨植物和土壤化学计量的空间格局和驱动因子,对于把握元素循环和量化生态系统对环境因子的响应具有重要意义。基于此,实验测定了祁连山北坡不同纬度青海云杉组织及土壤碳(C)氮(N)磷(P)含量,采用单因素方差分析(One-Way ANOVA)、皮尔逊相关分析(Pearson correlation)及冗余分析(Redundancy analysis, RDA)来揭示祁连山北坡不同纬度青海云杉及林下土壤化学计量特征及关键影响因素。结果表明：(1)青海云杉组织和土壤C、N含量随纬度增加而减少;而青海云杉组织N∶P、C∶P随纬度增加而增大,土壤N∶P、C∶P则减小。(2)青海云杉组织养分分配不均衡,C、N元素含量,叶>枝>根,而P元素含量,枝>叶>根,且青海云杉枝、根N∶P均小于14,表明祁连山青海云杉生长受土壤N元素的限制。(3)土壤因子(含水量、pH值、容重、SOC、TN、TP及SOC∶TN∶TP)及气候因子(年均气温和年均降水量)变化影响青海云杉组织N、P元素含量,且土壤因子对植物组织N、P、N∶P的解释率大于气候因子,其中,植物叶片N、N∶P与土壤TN、TN∶TP呈正相关(P<0.05),而植物根系N、N∶P值与气温呈负相关、与年均降水量呈显著正相关(P<0.05)。本研究有助于评估祁连山青海云杉生态系统养分动态变化,探索不同纬度青海云杉林养分调控分配机理,以期为祁连山森林生态系统的持续健康发展提供科学依据。 相似文献
5.
为了探究海拔和郁闭度对青海云杉林叶凋落物分解的影响,本文选择海拔为2850 m,3050 m,3250 m和3450 m四个梯度和高、中、低三个林分郁闭度,采用分解网袋法,研究青海云杉叶凋落物分解速率及分解过程中N、P元素变化。结果表明,质量损失率随时间在波动增大。分解速率先减小后增大,不同海拔下分解速率为K3450 > K3050 > K3250 > K2850,不同郁闭度下分解速率为K低 > K中 > K高,青海云杉叶枯落物分解50%和95%所需时间约为5.3 a和22.7 a。枯落物分解过程中,N、P含量和累积系数在不同海拔和郁闭度下的变化不同,与季节变化有关。研究结果为祁连山森林生态系统地球化学循环奠定基础。 相似文献
6.
祁连山青海云杉林生物量和碳储量空间分布特征 总被引：7，自引：0，他引：7
根据野外调查资料、祁连山地区青海云杉林相图和气象资料,在GIS技术的支持下估算了祁连山地区青海云杉林的生物量和碳储量及其空间分布.结果表明：2008年,研究区青海云杉林平均生物量为209.24 t·hm-2,总生物量为3.4×107 t;研究区水热条件的差异使青海云杉生物量在地理空间上存在较大的差异性;经度每增加1°,青海云杉生物量增加3.12t·hm-2;纬度每增加1°,生物量减少3.8 t·hm-2;海拔每升高100 m,生物量减少0.05 t·hm-2;2008年,研究区青海云杉林碳密度在70.4～131.1 t·hm-2,平均碳密度为109.8 t·hm-2,幼龄林、中龄林、近熟林、成熟林和过熟林的平均碳密度分别为83.8、109.6、122、124.2和117.1 t·hm-2,研究区青海云杉林总碳储量为1.8×107 t. 相似文献
7.
Different tree species exhibit different phenological and physiological characteristics, leading to complexity in inter-species comparison of stem radial growth response to climate change. This study explored the climate-growth responses of Qinghai spruce (Picea crassifolia) and Chinese pine (Pinus tabulaeformis) in the Qilian Mountains, Northwest China. Meanwhile, Vaganov-Shashkin model (VS-oscilloscope) was used to simulate the relationships between radial growth rates and phenology. The results showed that 1) in their radial growth patterns, Qinghai spruce showed a significant increasing trend, while Chinese pine showed a decreasing trend, and Qinghai spruce has a longer growing season than Chinese pine. 2) For the radial growth-climate dynamic response, Qinghai spruce was influenced in an unstable manner by the mean temperature in the mid-growing season of the current year and the late growing season of the previous year and by the mean minimum temperature in the mid-growing season of the current year, while Chinese pine was influenced in a stable manner by the mean temperature and mean maximum temperature during the growing season of the current year. 3) The radial growth rates of the two conifer species were limited by temperature at the initiation and cessation of growth and by soil moisture at the peak of growth. But Chinese pine was more severely affected by soil moisture than Qinghai spruce in the middle of growth. Therefore, different management and restoration measures should be taken based on the differences in ecological responses and physical and physiological properties of the two conifer species to climate change in the subalpine forest ecosystems in the semiarid and arid regions of Northwest China. 相似文献
8.
【目的】通过监测森林大样地植物群落特征的长期动态变化,揭示物种多样性空间格局及维持机制,为该区域的生物多样性保护提供科学依据。【方法】以祁连山区青海云杉林生态系统为研究对象,采用相邻格子法进行大样地乔木植株每木调查,并解析其生物多样性调控因素。【结果】青海云杉林生态系统的乔木总数为35 835株,青海云杉和祁连圆柏分别占据57.84%和23.82%。物种丰富度和平均株高分别为3种和10.7 m。Shannon-Wiener指数和Simpson指数分别为0.74和0.43,Shannon-Wiener指数偏低,但Simpson指数较高,存在物种数量集中度较高现象。森林大样地Shannon-Wiener受乔木高度、物种丰富度和Simpson指数的极显著影响。机器学习模型训练集和测试集的决定系数分别为0.95和0.93,均方根误差分别为0.06和0.08,表明模型对Shannon-Wiener指数的解释能力和预测精度均较高。【结论】青海云杉林物种多样性较低且受乔木高度、物种丰富度和Simpson指数的显著影响,其对维持该区域的生物多样性具有重要作用。 相似文献
9.
Northwestern China has experienced dramatic climate change characterized by rapid warming since the 1980s with the warming trend substantially slowing after 2000. Qinghai spruce (Picea crassifolia Kom.), a key tree species in northwest China, has been predicted to be strongly coupled with climate change. However, how the trends in biomass growth change at different canopy positions under climate change and whether climate–growth responses vary with canopy position remain unclear. A total of 222 trees were sampled by a stand-total sampling strategy in the central Qilian Mountains. Trees were assigned to four canopy positions according to height and distance from neighbors: dominant, codominant, intermediate, and suppressed. Our results indicate that trees in dominant and codominant canopy positions dominate the decreasing trend in stand-level biomass from 1980 to 2000 and the increasing trend from 2000–2013, contributing 81.3 % and 86 %, respectively, whereas trees in the intermediate and suppressed canopy positions contributed less. This result was attributed to a more sensitive response of biomass growth in trees in dominant and codominant canopy positions to climate change. From 1980 to 2000, the stronger decreasing trend in biomass growth at dominant and codominant canopy positions is mostly accounted for by increasing temperature. A more pronounced water deficit might have restricted biomass growth more than that at the intermediate and suppressed canopy positions. However, from 2000 to 2013, drought stress was relieved and summer standardized precipitation evapotranspiration index became a leading factor, which promoted the recovery in biomass at dominant and codominant canopy positions. In a word, compared with intermediate and suppressed canopy trees, those in dominant and codominant positions are less resistant to drought, but dominant and codominant canopy position's biomass can recover more when drought stress is relieved. A more robust understanding of canopy-level growth response and resilience to climate change is crucial to fully understand forest growth dynamics under fluctuating climate conditions. 相似文献
10.
As marine environments are influenced by global warming there is a need to thoroughly understand the relationship between physiological limits and temperature in fish. One quick screening method of a physiological thermal tipping point is the temperature at which maximum heart rate (ƒHmax) can no longer scale predictably with warming and is referred to as the Arrhenius break temperature (TAB). The use of this method has been successful for freshwater fish by using external electrodes to detect an electrocardiogram (ECG), however, the properties of this equipment pose challenges in salt water when evaluating marine fish. To overcome these challenges, this study aimed to explore the potential use of implantable heart rate loggers to quantify the TAB of Chrysoblephus laticeps, a marine Sparid, following the ECG method protocols where ƒHmax is monitored over an acute warming event and the TAB is subsequently identified using a piece-wise linear regression model. Of the nine experimental fish, only five (56%) returned accurate ƒHmax data. The TAB of successful trials was identified each time and ranged from 18.09 to 20.10 °C. This study therefore provides evidence that implantable heart rate loggers can estimate TAB of fish which can be applied to many marine species. 相似文献
11.
《Basic and Applied Ecology》2014,15(4):279-287
Environmental changes due to land use developments, climate change and nitrogen deposition have profound influences on species assemblages. Investigating the dynamics in species composition as a function of underlying traits may increase our understanding of ecosystem functioning and provide a basis for effective conservation strategies. Here, I use a broad array of species traits for butterflies to identify four main components of associated traits. These reflect the spatial use of the landscape, abiotic vulnerability, developmental rate and phenology, and food specialisation, respectively. The first three trait components each contribute to determine Red List status, but only the developmental rate and phenology component is related to recent population trends. I argue that the latter component reflects the environmental impact of nutrient availability and microclimate, as affected by nitrogen deposition. This perspective sheds a new light on ongoing changes in community composition. Thus, a multidimensional view of trait associations allows us to move beyond the simplistic specialist–generalist dichotomy, renew our view on species-specific studies and help in setting new priorities for conservation. 相似文献
12.
Ivan Romashkin Seppo Neuvonen Olli‐Pekka Tikkanen 《Agricultural and Forest Entomology》2020,22(3):238-249
- As the development of the eight‐toothed spruce bark beetle Ips typographus is temperature‐dependent, climate change may encourage development of its additional generations per year and facilitate mass outbreaks further north than previously known.
- The aim of the study was to analyse historical changes in effective temperature sums (ETSs) and early season swarming weather for I. typographus in different forest zones of European Russia between 1960 and 2016. The difference in ETSs was analysed with linear regression using daily temperature data from the 30 meteorological stations. Historical data regarding the location of I. typographus outbreaks were examined and changes in their distribution during the entire study period were analysed.
- There was a substantial increase in ETSs, especially in the latter half of the study period. Increased ETSs coincided with more favourable conditions for swarming of I. typographus. Areas with favourable ETSs for the complete development of bivoltine populations of I. typographus (>1500 DD) shifted northwards on average 450 km during the entire study period.
- The northward shift of ETSs may enhance the transition from univoltine to bivoltine life cycles of I. typographus in the south and middle taiga and from bivoltine to trivoltine life cycles in conifer‐broadleaf forests.
13.
Adam Felton Joern Fischer David B. Lindenmayer Rebecca Montague-Drake Arianne R. Lowe Debbie Saunders Annika M. Felton Will Steffen Nicola T. Munro Kara Youngentob Jake Gillen Phil Gibbons Judsen E. Bruzgul Ioan Fazey Suzi J. Bond Carole P. Elliott Ben C. T. Macdonald Luciana L. Porfirio Martin Westgate Martin Worthy 《Biodiversity and Conservation》2009,18(8):2243-2253
Recent reviews of the conservation literature indicate that significant biases exist in the published literature regarding
the regions, ecosystems and species that have been examined by researchers. Despite the global threat of climatic change,
similar biases may be occurring within the sub-discipline of climate-change ecology. Here we hope to foster critical thought
and discussion by considering the directions taken by conservation researchers when addressing climate change. To form a quantitative
basis for our perspective, we assessed 248 papers from the climate change literature that considered the conservation management
of biodiversity and ecosystems. We found that roughly half of the studies considered climate change in isolation from other
threatening processes. We also found that the majority of surveyed scientific publications were conducted in the temperate
forests of Europe and North America. Regions such as Latin America that are rich in biodiversity but may have low adaptive
capacity to climate change were not well represented. We caution that such biases in research effort may be distracting our
attention away from vulnerable regions, ecosystems and species. Specifically we suggest that the under-representation of research
from regions low in adaptive capacity and rich in biodiversity requires international collaboration by those experienced in
climate-change research, with researchers from less wealthy nations who are familiar with local issues, ecosystems and species.
Furthermore, we caution that the propensity of ecologists to work in essentially unmodified ecosystems may fundamentally hamper
our ability to make useful recommendations in a world that is experiencing significant global change. 相似文献
14.
祁连山作为我国重要的生态功能区、西北地区重要的生态安全屏障和河流产流区,是气候变化敏感区和生态环境脆弱区,其生态环境对西北地区经济发展起着重要作用。本研究利用祁连山区气温和降水观测数据、MOD10A2积雪产品以及石羊河、黑河和疏勒河流量资料,系统分析了1961—2020年祁连山区的气候变化特征,以及在气候变暖背景下,气候变化对祁连山区水资源的影响。结果表明: 1961—2020年,祁连山区平均气温呈显著上升趋势,升温速率达0.39 ℃·(10 a)-1,西段升温速率最大,中、东段次之,冬季升温趋势最显著,春季最小;祁连山区平均气温在1997年发生突变。祁连山区年降水量总体呈波动增加趋势[10 mm·(10 a)-1],中段增加最明显,2004年以来祁连山区处于多雨时期,气候呈暖湿化趋势;四季降水量均呈增加趋势,夏季降水增加对年降水贡献最大;年降水以年际尺度变化为主,2.8年的年际尺度贡献率高达64.3%。祁连山积雪面积受气温和降雪影响明显,与夏季气温存在负相关,与降雪量存在正相关;2016—2020年,祁连山增温趋缓、降雪增多,积雪面积呈增加趋势。2000年以来,祁连山升温加剧,降水增多,冰雪融水增加,石羊河、黑河和疏勒河出山径流均呈增加趋势。研究结果对祁连山区生态文明建设和应对气候变化具有重要意义。 相似文献
15.
祁连山生态环境保护是建设我国西部生态安全屏障的关键环节,而核算祁连山生态系统服务价值是制定合理有效的生态环境保护措施的有力依据。然而受气候变化和人类活动的共同影响,祁连山地区生态环境问题依旧突出,亟需对该地区生态系统服务价值开展研究以服务后期生态环境建设。基于此目的,使用1990—2020年祁连山地区土地利用数据,运用土地利用动态度、土地利用转移矩阵揭示该地区土地利用变化规律。并使用生态系统服务价值评估模型测算了祁连山地区生态系统服务价值,探究了其动态变化过程,并明确了各土地利用类型与生态系统服务价值变化之间的内在联系。结果表明：(1)1990—2020年,草地和荒漠是祁连山地区最主要的土地利用类型,单一土地利用动态度分别为水域>湿地>耕地>荒漠>草地>林地。草地和耕地以及草地和荒漠相互转化成为该地区最主要的土地利用变化特征;(2)祁连山地区生态系统服务价值呈持续增加趋势,由1990年的7231.36亿元增加至2020年的7836.07亿元,在空间上呈现出东高西低的变化趋势。生态系统服务价值构成主体主要为水域、草地和林地,单项生态系统服务价值以水文调节和气候调节为主,反映了调节服务是祁连山地区生态系统的主要功能;(3)水域、草地和湿地这3种土地利用类型是近30年祁连山地区生态系统服务价值变化的主要贡献因子。1990—2020年,祁连山地区生态系统服务价值对土地利用的敏感性总体呈增加态势(1.48%—7.91%),土地利用变化对该地区生态系统服务价值的影响逐步增强。系统揭示了过去30年祁连山地区生态系统服务价值的演变及其与土地利用变化的内在联系,重点阐释了水域、草地、林地和湿地对该地区生态系统服务价值和生态环境保护的重要性,可为祁连山地区生态产品价值实现及生态保护管理等提供基础科技支撑。 相似文献
16.
Annually resolved and absolutely dated Maximum Latewood Density (MXD) and Blue Intensity (BI) measurements are frequently used for reconstructing summer temperature variability over the last centuries to millennia. A direct comparison of the outcome of both methods using similar material is needed due to how quickly this method is being adopted. The application of slightly different measuring systems (hardware) and analysis tools (software) in tandem with different wood samples and preparation procedures further challenges any straightforward assessment. Here we process 26 Norway spruce samples from the upper timberline in the Polish Tatra Mountains with the six most frequently used MXD and BI applications. Although offset is found in the raw MXD and BI data (0.04–0.13 g/cm3 and 0.45–1.58 dimensionless blue intensity), interannual and longer-term fluctuations are significantly (p < 0.01) positively correlated between all MXD and BI time-series. Our results emphasize the potential of faster and cheaper, as well as overall more user-friendly techniques to generate reliable MXD surrogates for high-frequency dendroclimatological studies. Although the correlations between MXD and BI were lower than within MXD and BI, the results of growth-climate response performed for both proxies show only marginal differences. The obtained level-offset further questions the suitability of joining different density surrogates for developing long-term composite chronologies to reconstruct low-frequency climate variability. 相似文献
17.
Mauricio Lima 《Ecology and evolution》2014,4(3):284-291
Population dynamics, economy, and human demography started with Malthus, the idea that population growth is limited by resources and “positive checks” occur when population growth overshoots the available resources. In fact, historical evidence indicates that long‐term climate changes have destabilized civilizations and caused population collapses via food shortages, diseases, and wars. One of the worst population collapses of human societies occurred during the early fourteenth century in northern Europe; the “Great Famine” was the consequence of the dramatic effects of climate deterioration on human population growth. Thus, part of my motivation was to demonstrate that simple theoretical‐based models can be helpful in understanding the causes of population change in preindustrial societies. Here, the results suggest that a logistic model with temperature as a “lateral” perturbation effect is the key element for explaining the population collapse exhibited by the European population during the “Great Famine”. 相似文献
18.
植被净初级生产力(NPP)是评价植被生长的重要参数,也是评估陆地生态系统质量与功能的重要指标。基于MODIS NPP、数字高程模型(DEM)、气象水文及人类活动数据,采用空间分析、趋势分析,分别从像元尺度和县域尺度识别了2000-2020年以来祁连山NPP时空变化特征,采用偏相关分析研究了NPP对年均温和年降水的响应,并借助地理探测器模型揭示了NPP变化的驱动因素,最后采用Hurst指数预测了NPP未来变化趋势。结果表明:2000-2020年祁连山平均NPP呈波动增加趋势,年均增加2.38 g C/m2,其中栽培植被和阔叶林增长最为明显。近20年,像元尺度上有75.37%的区域NPP增加,主要位于东南部;县域尺度上,古浪、平安、化隆和永登县NPP增速较快,而祁连、海西、德令哈和门源县增速较慢。祁连山NPP空间分布具有明显的集聚性,高值集聚区主要位于东南部,而低值集聚区主要位于西北部。年均温和降水量的增加均促进了NPP的增加,但不同区域NPP对气温和降水的响应有明显差异。降水量、饱和水气压差和蒸散发是NPP变化的主要驱动因子,驱动因子之间对植被NPP变化存在交互作用,分为双因子增强和非线性增强效应。未来祁连山NPP变化以增加非持续性为主,说明植被变化面临较大不确定性。研究结果有助于揭示全球气候变化背景下区域植被NPP对气候变化及人类活动的非线性响应机制,亦可为祁连山生态保护与可持续发展提供理论依据。 相似文献
19.
Mitigation of climate change (CC) is a regulating ecosystem service provided by priority habitats that is often co-delivered alongside their conservation of biodiversity. Carefully planned conservation management is thought necessary to support biodiversity adaptation to CC, but could also contribute to CC mitigation. This paper presents a methodology for assessing direct emissions of greenhouse gases (GHG: CO2, CH4 and N2O) from 12 UK priority habitats in 26 Special Areas of Conservation (SAC) using readily available data. Background emissions are estimated on the basis of published field research. The contribution of conservation management to GHG emission reduction is estimated using the IPCC GHG accounting methodology and other methods. Management Data Acquisition surveys carried out at selected SACs provided data on management practises for Scotland and Wales. Climate change mitigation actions identified in this study for priority habitats included livestock removal or change in stocking density, with GHG reduction potential of up to 3 tCO2e/animal/year, afforestation of acid grasslands—up to 19.4 tCO2e/ha/year, wetland restoration—0.3–0.8 tCO2e/ha/year and cessation of moorland burning—6.9 tCO2e/ha/year. Estimated GHG emissions from priority habitats can be used to identify win:win management options that co-deliver GHG mitigation, climate adaptation and conservation benefits for consideration by policy makers and conservation managers. 相似文献
20.
The Amazon rainforest covers more than 60% of Bolivia’s lowlands, providing habitat for many endemic and threatened species. Bolivia has the highest rates of deforestation of the Amazon biome, which degrades and fragments species habitat. Anthropogenic habitat changes could be exacerbated by climate change, and therefore, developing relevant strategies for biodiversity protection under global change scenarios is a necessary step in conservation planning.In this research we used multi-species umbrella concept to evaluate the degree of habitat impacts due to climate and land cover change in Bolivia. We used species distribution modeling to map three focal species (Jaguar, Lowland Tapir and Lesser Anteater) and assessed current protected area network effectiveness under future climate and land cover change scenarios for 2050.The studied focal species will lose between 70% and 83% of their ranges under future climate and land-cover change scenarios, decreasing the level of protection to 10% of their original ranges. Existing protected area network should be reconsidered to maintain current and future biodiversity habitats. 相似文献