Plant drought tolerance trait is the key parameter in improving the modeling of terrestrial transpiration in arid and semi-arid regions   总被引：1，自引：0，他引：1       下载免费PDF全文

Xintao Liu  Xingjie Lu  Shulei Zhang  Zhongwang Wei  Nan Wei  Shupeng Zhang  Hua Yuan  Wei Shangguan  Shaofeng Liu  Jianfeng Huang  Lu Li  Xiulan Ye  Jinxuan Zhou  Wenke Hu  Yongjiu Dai 《大气和海洋科学快报》2022,15(1):35-41

陆面过程蒸腾作用的模拟制约着天气,气候降水预测的精确度.近几十年来,为了更好地描述植被蒸腾的水力约束,陆面过程模式发展了基于植物性状的植物水力胁迫方案.然而,我们对于植物性状在蒸腾模拟中的地位仍然缺乏了解,植物性状对蒸腾的重要性仍需进一步量化.本研究利用Morris方法评估植物性状参数在通用陆面模式植物水力胁迫方案(CoLM-P₅₀HS)中的重要性,针对17种植物性状,筛选出最为重要的:耐旱性状(P₅₀),气孔性状,和光合作用性状.在12个FLUXNET站点中,参数的重要性由归一化敏感度来衡量.P₅₀的重要性随着降水的减少而增加,而气孔性状和光合作用性状的重要性则随着降水的减少而减少.在干旱或半干旱地区,P₅₀比气孔性状和光合作用性状更重要,这意味着当植物经常经历干旱时,水力安全策略比植物生长策略更关键.而耐旱性状的巨大变异性进一步暗示了多种植物水力安全策略的共存.忽视P₅₀的变异性可能会对陆面过程模式蒸腾作用的模拟造成严重误差.因此,为了更好地表示植物水力功能的变异性,需要增加对耐旱性状的观测并耦合到陆面模式中.  相似文献   

The imprint of plants on ecosystem functioning: A data-driven approach     

《International Journal of Applied Earth Observation and Geoinformation》2015

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近岸海域大型水母来源与迁移路径分析——以红沿河电厂海域为例     

孙雪  魏皓  张海彦  王彦涛  张广跃  刘汉霖 《海洋与湖沼》2019,50(6):1281-1291

近岸海域水母暴发可导致滨海火/核电厂取水口堵塞,对电厂安全运行造成潜在威胁。寻找水母源地及其迁移路径是水母治理的基础。本文基于拉格朗日质点追踪方法(LTRANS)建立反向追踪模型,并结合水母生态学特性对2015年6—9月聚集在红沿河电厂海域的大型水母进行溯源,获得水母源地及迁移路径,可以为螅状体栖息地寻找和水母拦截打捞提供依据,对近岸海域水母灾害防治具有重要指导意义。溯源结果表明:(1)红沿河电厂及其邻近海域的水母可能来自多个不同源区,辽东湾西部、北部及电厂南北两侧等海域的水母均有可能迁移至电厂附近;(2)受水温和环流影响,6—9月期间到达电厂附近的水母主要源区及迁移路径不同,早期出现在电厂海域的水母很可能是局地产生的,而7—9月持续的高风险水母灾害则主要取决于渤海不同源区水母的物理聚集;(3)根据水母的主要迁移路径,建议在电厂取水口约15km的海域设置一条封闭监测断面,对水母进行实时监测;在距离取水口约30km的外侧海域设置一条调查断面,于7月初至8月中旬,每5天进行一次定点拖网调查。此外,在距离电厂取水口15—20km的西南方向上,对水母进行拦截打捞可大大降低水母入侵风险。  相似文献   

Associated terrestrial and marine fossils in the late-glacial Presumpscot Formation, southern Maine, USA, and the marine reservoir effect on radiocarbon ages   总被引：1，自引：0，他引：1  

Woodrow B. Thompson  Carol B. Griggs  Norton G. Miller  Robert E. Nelson  Thomas K. Weddle  Taylor M. Kilian   《Quaternary Research》2011,75(3):552-565

Excavations in the late-glacial Presumpscot Formation at Portland, Maine, uncovered tree remains and other terrestrial organics associated with marine invertebrate shells in a landslide deposit. Buds of Populus balsamifera (balsam poplar) occurred with twigs of Picea glauca (white spruce) in the Presumpscot clay. Tree rings in Picea logs indicate that the trees all died during winter dormancy in the same year. Ring widths show patterns of variation indicating responses to environmental changes. Fossil mosses and insects represent a variety of species and wet to dry microsites. The late-glacial environment at the site was similar to that of today's Maine coast. Radiocarbon ages of 14 tree samples are 11,907 ± 31 to 11,650 ± 50 ¹⁴C yr BP. Wiggle matching of dated tree-ring segments to radiocarbon calibration data sets dates the landslide occurrence at ca. 13,520 + 95/−20 cal yr BP. Ages of shells juxtaposed with the logs are 12,850 ± 65 ¹⁴C yr BP (Mytilus edulis) and 12,800 ± 55 ¹⁴C yr BP (Balanus sp.), indicating a marine reservoir age of about 1000 yr. Using this value to correct previously published radiocarbon ages reduces the discrepancy between the Maine deglaciation chronology and the varve-based chronology elsewhere in New England.  相似文献   

Differential utilization of a shallow-water pulse by six shrub species in the Patagonian steppe     

E. KowaljowR.J. Fernández 《Journal of Arid Environments》2011,75(2):211-214

A field experiment was performed to improve understanding of the functional diversity of western Patagonian shrubs. Anarthrophyllum rigidum, Adesmia volckmanni, Berberis heterophylla, Mulinum spinosum, Schinus poligamus and Senecio filaginoides were compared in their capacity to absorb water from a 10-mm pulse enriched in deuterium and applied at the beginning of the dry summer. Xylem-water enrichment 14 days after watering was rather subtle, but the upper-soil signal was clear enough to distinguish shallow from deeper absorption. According to a linear mixing model, the proportion of surface-pulse water relative to total water uptake was maximum for Senecio (29-38%) and Mulinum (22-32%), both relatively shallow-rooted species, intermediate for Berberis (16-17%) and Schinus (6-9%), and negligible for the two N-fixing Fabaceae: Adesmia (<1%) and Anarthrophyllum (<3%), despite this last one having a dimorphic (tap + shallow) root system. It is hypothesized that shallow-water pulses may be more profitable in terms of nitrogen than of water, and thus constitute a higher-quality resource for those species only able to use N from soil sources.  相似文献   

Herbaceous layer development during spring does not deplete soil nitrogen in the Portuguese montado     

D.O. Otieno  H. MirzaeiM.Z. Hussain  Y.L. LiM.W.T. Schmidt  M. Wartinger  E. Jung  N. RibeiroJ.S. Pereira  J. Tenhunen 《Journal of Arid Environments》2011,75(3):231-238

Nitrogen (N) content in the soil and in the herbaceous biomass were monitored during spring of 2004-2006 to determine how the herbaceous layer development influences soil N availability in the montado ecosystem of southern Portugal. Highest (246.6 ± 52.7 g m⁻²) and lowest (123.2 ± 89.5 g m⁻²) peak biomass occurred in 2006 and 2005 respectively. Total soil N within the top 20 cm soil profile ranged between 0.2 ± 0.1% in February and 0.41 ± 0.2% in May, while available soil N was lowest (5 ± 2 μg g⁻¹soil) in February but increased three-to-five fold in March and was >17.5 μg g⁻¹soil at senescence in May. Significant (p < 0.001) increase in total N in the aboveground pool occurred between February and May. There was however, no decay in soil N content. Instead, the herbaceous vegetation enhanced soil N input and N retention in the ecosystem. Most of the herbaceous plants were annuals with large reserves of organic N at senescence, which returned to the soil as detritus. The herbaceous vegetation is a critical component of the montado that contributes to N recharge and cycling within the ecosystem.  相似文献   

Influence of livestock on the regeneration of fodder trees along ephemeral rivers of Namibia     

P.M. Moser-Nørgaard  M. Denich 《Journal of Arid Environments》2011,75(4):371-376

Faidherbia albida and Acacia erioloba (Mimosoideae) are important fodder trees for livestock and wildlife along the westward flowing ephemeral rivers of the Namib Desert. Together with other, mainly woody vegetation, F. albida and A. erioloba line these rivers and present a linear oasis in a resource poor environment. For centuries nomadic to semi-nomadic inhabitants seasonally utilised the resources of these ephemeral rivers to survive in the otherwise harsh desert environment. In the past decades, more permanent settlements were established along these rivers, with small stock subsistence farmers making a living from the available resources. Livestock (mainly goats) usually moves freely around, feeding on the available vegetation.This study investigated the influence of free moving animals on the regeneration and recruitment of F. albida and A. erioloba along the Kuiseb ephemeral river. It was found that a large numbers of recently emerged seedlings were removed soon after germination. In addition, tree densities of adult versus juvenile individuals differed in areas with large numbers of livestock. The overall height increase and health of juvenile plants were influenced negatively by browsing livestock. In general, browsing pressure differed spatially and was higher close to the main water channel.  相似文献   

Positive plant interactions in the Iberian Southeast: Mechanisms, environmental gradients, and ecosystem function     

F.I. Pugnaire  C. Armas  F.T. Maestre 《Journal of Arid Environments》2011,75(12):1310-1320

Semi-arid ecosystems are privileged sites to address the effects of plant interactions on community structure and dynamics because environmental conditions are demanding and may change quickly, altering in significant ways the balance between positive and negative effects among neighboring plants. Plant interaction processes have been well documented in the semi-arid region of Southeast Spain over the last 15 years. In this article we review the growing body of research on plant–plant interactions available from this area, highlighting its importance in increasing our knowledge on this field of study. This review has been organized in five sections, i) facilitation mechanisms; ii) the nurse effect; iii) the balance of interactions and environmental, ontogenic, temporal, and spatial gradients; iv) the effects of facilitation on biodiversity; and, v) facilitation and ecosystem functioning. Mechanisms of facilitation in these systems are relatively well known, but not completely explored. In these environments competition, mainly for water, is intense between neighbors and switches in intensity from belowground to aboveground as productivity increases. By contrast, facilitation may decrease quickly with increasing productivity, although the balance between facilitation and competition is not fully understood, and is further complicated because shifts can also be driven by factors such as life history or physiology of interacting species. Positive interactions are critical for maintaining biodiversity in some ecosystems in SE Spain, but their role as a driver of ecosystem functioning is less clear. Research on plant–plant interactions in this region has been highly influential and has contributed to our overall understanding of plant community dynamics. Despite the important progress achieved during the last 15 years, there is still substantial scope for exploring the effects of plant interactions at the ecosystem level, and their role as modulators of disturbances such as the current global environmental change.  相似文献   

衡水市滏阳河景观带植被配置分析     

刘红霞  李惠欣 《湿地科学与管理》2015,11(2):12-14

调查了衡水滏阳河岸景观带植被配置现状,在剖析景观带植被配置优势和问题的基础上,从适地适树,丰富季相景观,注重种植密度及乔灌藤花草合理搭配等方面提出了改进措施,以促进本区植被配置优化,充分发挥河岸植被的生态效益和社会效益。  相似文献   

Seasonal Dynamics of Rhizosphere Soil Microbial Abundances and Enzyme Activities under Different Vegetation Types in the Coastal Zone,Shandong, China          下载免费PDF全文

Gang Xu  Peng Chen  Jun‐Na Sun  Hong‐Bo Shao 《洁净——土壤、空气、水》2014,42(8):1115-1120

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