北部湾典型入海流域植被CUE时空变化特征及驱动力因素分析     

张亚丽  梁晓燕  田义超  林俊良  王栋华 《测绘通报》2023,(8):1-6

植被碳利用效率(CUE)反映了植被生态系统在碳储存方面的效率,对于“双碳”政策背景下植被碳循环研究具有重要参考价值。本文基于MODIS数据、气象数据、DEM数据,采用趋势分析、变异系数、Hurst指数等方法,对北部湾典型入海流域2001—2020年植被CUE时空变化特征展开了研究。结果表明：(1)时间上,CUE年均值呈显著下降趋势(P<0.01),年际变化率均值为-0.003/a;年际CUE波动程度较小,整体上较为稳定。(2)空间上,北部湾典型入海流域CUE多年均值介于0.08～0.60之间,流域整体平均值为0.465。CUE年均值从高到低依次为,北仑河流域、钦江流域、江平江流域、防城江流域、茅岭江流流域、南流江流域、大风江流。(3)驱动力因素上,气温对北部湾典型入海流域植被CUE变化起主要控制作用,其次为高程和降水,土壤类型、坡度对植被CUE的驱动有限。  相似文献   

面向植被均质单元的生物量多尺度估算研究     

杜英坤  胡华浪  王静  裴志远  姜雷  杨唯  苏飞 《测绘科学》2023,(1):176-188

针对以往植被地上生物量(以下简称“生物量”)多尺度估算方法在数据收集、尺度转化、结果呈现等方面的局限,该文提出了面向植被均质单元的生物量多尺度估算方法：(1)定义了具有实际景观意义的植被均质单元,作为植被生物量估算的基本单元;(2)基于多源数据提取直接反映和间接影响植被生物量的多源因子,利用多尺度分割技术构建多尺度下的植被均质单元;(3)通过随机森林回归模型实现植被生物量多尺度估算。结果表明,该方法可避免多尺度下的数据获取,仅基于一套数据实现了研究区植被生物量多尺度估算,产生了较好的建模和估算精度。该方法不仅可量化生物量大小,还可描绘生物量均质区域,具有尺度变换便捷、灵活等优势。  相似文献   

基于无人机影像的无瓣海桑单木提取与地上生物量估算     

余楚滢  龚辉  曹晶晶  刘燕君  刘凯 《热带地理》2023,43(1):12-22

无瓣海桑(Sonneratia apetala)是中国红树林恢复种植最早引进的优质红树树种,其生产力在红树林群落中处于较高水平,具有显著的高生物量和能量积累。然而,由于红树林群落冠层密集、结构复杂,精确描绘无瓣海桑的单木树冠存在极大挑战性。传统的卫星遥感侧重于区域或更大尺度监测需求,而新兴的低空无人机遥感在更精细尺度的红树林生态监测中具有显著优势。以广东省珠海市淇澳岛红树林自然保护区为研究区,利用消费级无人机影像生成的冠层高度模型(Canopy Height Model, CHM)和种子区域生长(Seed Region Growing, SRG)算法进行无瓣海桑单木树冠提取,并建立基于地面调查数据获取的树高和胸径两者之间的回归关系,以优化无瓣海桑地上生物量异速生长方程,进而实现研究区单木尺度的无瓣海桑地上生物量估算。结果表明：基于无人机影像可以有效提取无瓣海桑单木树冠,其提取精度达到67%;验证了树高和胸径之间较高的相关性,提出了基于树高的无瓣海桑地上生物量异速生长方程;研究区无瓣海桑平均地上生物量的范围为2.99～247.24 t/hm²,平均值为92.14 t...  相似文献   

Root structure,distribution and biomass in five multipurpose tree species of Western Himalayas   总被引：1，自引：0，他引：1  

Kartar Singh VERMA  Sandeep KOHLI  Rajesh KAUSHAL  Om Parkash CHATURVEDI 《山地科学学报》2014,11(2):519-525

【Title】

【Author】

【Addresses】1

The tree root distribution pattern and biomass of seventeen year old trees of Grewia optiva, Morus alba, Celtis australis, Bauhinia variegata and Robinia pseudoacacia were studied by excavation method. B. variegata roots penetrated to a maximum depth of 4.78 m, whereas, M. alba roots were found down to 1.48 m depth. Lateral spread was minimum in B. variegata （1.10 m）and maximum inR. pseudoacacia （7.33 m）. Maximum root biomass of 6.30 kg was found in R. pseudoacacia and minimum （2.43 kg） was found in M. alba. For four species viz.,G. optiva, M. alba, C. australis andR. pseudoacacia, 68%-87% root biomass occurred within top 0-30 cm soil depth, but forB. variegata this was only45%. The soil binding factor was maximum in G. optiva and minimum in B. variegata. Soil physico-chemical properties also showed wide variation. The study suggests thatB. variegata with a deep root system is the most suitable species for plantation under agroforestry systems. R. pseudoacacia and G. optiva with deep root systems, more lateral spread and high soil binding factor are suitable for plantation on degraded lands for soil conservation.  相似文献   

洪泽湖典型水生植物群落碳储量   总被引：1，自引：0，他引：1  

潘宝宝  张金池  冯开宇  陈家栋  郭晓平 《湿地科学》2014,(4)

于2012年4月6日、7月5日、9月8日和12月11日,在洪泽湖湿地国家级自然保护区内,进行典型植物群落调查,选取芦苇(Phragmites australis)、荷花(Nelumbo nucifera)、水花生(Alternanthera philoxeroides)、浮萍(Lemna minor)、金鱼藻(Ceratophyllum demersum)和菹草(Potamogeton crispus)群落为研究对象,研究这些植物群落的生物量、植物碳储量和土壤碳储量。结果表明,在各植物群落的平均生物量中,芦苇群落的平均生物量最大,为4 553.47g/m2;芦苇群落地下部分与地上部分生物量的平均根冠比为3.03,荷花群落为0.67;芦苇群落、荷花群落、金鱼藻群落、水花生群落、浮萍群落和菹草群落的平均土壤碳储量分别为5.32 kg/m2、3.83 kg/m2、2.35 kg/m2、2.11 kg/m2、1.57 kg/m2和1.33 kg/m2;芦苇群落、荷花群落、菹草群落、金鱼藻群落、水花生群落和浮萍群落的平均植物碳储量分别为2.25 kg/m2、0.51 kg/m2、0.19 kg/m2、0.11 kg/m2、0.09 kg/m2和0.05 kg/m2;芦苇群落、荷花群落、金鱼藻群落、水花生群落、浮萍群落和菹草群落的平均碳储量分别为7.57 kg/m2、4.34 kg/m2、2.46 kg/m2、2.20 kg/m2、1.62 kg/m2和1.52 kg/m2。  相似文献   

Zooplankton community structure in relation to environmental factors and ecological assessment of water quality in the Harbin Section of the Songhua River     

李晓钰  于洪贤  马成学 《中国海洋湖沼学报》2014,32(6):1344-1351

To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River, investigations were carried out in June, August, and October 2011. Canonical correspondence analysis （CCA） and saprobic indices were used to process and analyze the data. Seasonal variability was identified as a significant source of variation, which explains the fluctuation in zooplankton density. In autumn, the dry season, water residence time increased and zooplankton biomass and abundance accumulated in the slow flowing waters. Zooplankton abundance increased when food conditions improved. Therefore, the total zooplankton abundance in autumn is much higher than that in spring and summer. According to the saprobic indices, all the sample sites had mesosaprobic water and water quality was worse in autumn. CCA revealed that temperature accounted for most of the spatial variation in the zooplankton community. Moreover, pH, dissolved oxygen saturation, and turbidity were important factors affecting zooplankton community distribution.  相似文献   

Effects of Nitrogen Addition on Plant Functional Traits in Freshwater Wetland of Sanjiang Plain,Northeast China   总被引：1，自引：0，他引：1  

MAO Rong  ZHANG Xinhou  SONG Changchun 《中国地理科学(英文版)》2014,(6):674-681

To clarify the responses of plant functional traits to nitrogen（N） enrichment, we investigated the whole-plant traits（plant height and aboveground biomass）, leaf morphological（specific leaf area（SLA） and leaf dry mass content（LDMC）） and chemical traits（leaf N concentration（LNC） and leaf phosphorus（P） concentration（LPC）） of Deyeuxia angustifolia and Glyceria spiculosa following seven consecutive years of N addition at four rates（0 g N/（m^2·yr）, 6 g N/（m^2·yr）, 12 g N/（m^2·yr） and 24 g N/（m^2·yr）） in a freshwater marsh in the Sanjiang Plain, Northeast China. The results showed that, for both D. angustifolia and G. spiculosa, N addition generally increased plant height, leaf, stem and total aboveground biomass, but did not cause changes in SLA and LDMC. Moreover, increased N availability caused an increase in LNC, and did not affect LPC. Thus, N addition decreased leaf C∶N ratio, but caused an increase in leaf N∶P ratio, and did not affect leaf C∶P ratio. Our results suggest that, in the mid-term, elevated N loading does not alter leaf morphological traits, but causes substantial changes in whole-plant traits and leaf chemical traits in temperate freshwater wetlands. These may help to better understand the effects of N enrichment on plant functional traits and thus ecosystem structure and functioning in freshwater wetlands.  相似文献   

Distributions of Picophytoplankton and Phytoplankton Pigments Along a Salinity Gradient in the Changjiang River Estuary,China     

WANG Baoli  ;LIU Congqiang  ;WANG Fushun  ;LI Siliang  ;Sivaji Patra 《青岛海洋大学学报(英文版)》2014,(4):621-627

We investigated the abundance of different picophytoplankton groups and the phytoplankton pigment ratio in relation to environmental factors such as nutrients and suspended solids along a salinity gradient in the Changjiang River Estuary.The average numbers of Synechococcus spp.（Syn） and picoeukaryotes （Euk） were （2.7 ±5.1）×l03 and （1.1±1.4）×l03 cells mL-1,respectively.Prochlorococcus spp.（Pro） was only found in the high-salinity brackish water with the concentration of 3.0× 10^3 cells mL-1.Syn and Euk numbers both tended to increase offshore and Syn showed a larger variation in cell abundance than Euk.The contribution of picophytoplankton to total phytoplankton biomass increased with increasing salinity and decreasing nutrient concentrations from the estuary to the open ocean.The response of different picophytoplankton groups to environmental variables was different.Water temperature was more important in its control over Euk than over Syn,while nutrients were more important in their influence over Syn than over Euk.Phytoplankton pigment ratios were different in the three different ecological zones along the salinity gradient （i.e.,freshwater zone with 0-5 range,fresh and saline water mixing zone with 5-20 range,and high-salinity brackish water zone with 20-32 range）,where three different phytoplankton communities were discovered,suggesting that phytoplankton pigment ratios can be considered as a complementary indicator of phytoplankton community structure in the Changjiang River Estuary.  相似文献   

The Soil Moisture and Net Primary Production Affected by CO_2 and Climate Change Using a Coupled Model          下载免费PDF全文

PENG Jing  DAN Li 《大气和海洋科学快报》2014,(4):269-274

In this paper, a coupled model was used to estimate the responses of soil moisture and net primary production of vegetation （NPP） to increasing atmospheric CO2 concentration and climate change. The analysis uses three experiments simulated by the second-generation Earth System Model （CanESM2） of the Canadian Centre for Climate Modelling and Analysis （CCCma）, which are part of the phase 5 of the Coupled Model Intercomparison Project （CMIP5）. The authors focus on the magnitude and evolution of responses in soil moisture and NPP using simulations modeled by CanESM, in which the individual effects of increasing CO2 concentration and climate change and their combined effect are separately accounted for. When considering only the single effect of climate change, the soil moisture and NPP have a linear trend of 0.03 kg m^-2 yr^-1 and-0.14 gC m^- 2 yr^-2, respec- tively. However, such a reduction in the global NPP results from the decrease of NPP at lower latitudes and in the Southern Hemisphere, although increased NPP has been shown in high northern latitudes. The largest negative trend is located in the Amazon basin at -1.79 gC m^-2 yr^-2. For the individual effect of increasing CO2 concentration, both soil moisture and NPP show increases, with an elevated linear trend of 0.02 kg m^-2 yr^-1 and 0.84 gC m^-2 yr^-2, respectively. Most regions show an increasing NPP, except Alaska. For the combined effect of increasing atmospheric CO2 and climate change, the increased soil moisture and NPP exhibit a linear trend of 0.04 kg m^2 yr^-1 and 0.83 gC m^2 yr^-2 at a global scale. In the Amazon basin, the higher reduction in soil moisture is illustrated by the model, with a linear trend of-0.39 kg m^-2 yr^-1, for the combined effect. Such a change in soil moisture is caused by a weakened Walker circulation simulated by this coupled model, compared with the single effect of increasing CO2 concentration （experiment M2）, and a consequence of the reduction in NPP is also shown in this area, with a linear trend of-  相似文献   

2012年冬季菲律宾海浮游动物丰度和生物量的水平分布   总被引：1，自引：1，他引：0  

代鲁平  李超伦  孙晓霞  吉鹏  张武昌 《海洋与湖沼》2014,45(6):1225-1233

为了解西太平洋菲律宾海浮游动物丰度和生物量的水平分布特征,于2012年11月26日至2012年12月12日对菲律宾海上层海洋(0—200m)的浮游动物进行了调查。调查站位分别位于受赤道逆流(NECC)、棉兰老流(MC)、北赤道流(NEC)和黑潮(KC)影响的海域。通过比较浮游动物的丰度和生物量(分别用干重,灰分,无灰干重和含能量等指标表示),探讨不同海流中浮游动物的分布特征。结果表明:桡足类、毛颚类和水母类是菲律宾海浮游动物的三大主要类群。调查海域浮游动物丰度为11—116ind./m3,NECC区平均丰度最高((96±28)ind./m3),然后依次是MC区和KC区,NEC区最小((26±9)ind./m3)。在浮游动物生物量(干重)方面,同样NECC区最高((3.25±1.11)mg/m3),其次为MC区,但是平均丰度最小的NEC区生物量超过KC区。造成这一差异的主要原因,可能是由于KC区的浮游动物具有更高的含水量以及较小个体所占比例较高。不同水团之间浮游动物灰分、无灰干重和含能量的分布特征与干重相一致。结合环境因子分析显示,上升流、叶绿素a、初级生产力、海流和温度等因素对浮游动物的分布具有一定影响。  相似文献