火干扰对小兴安岭白桦沼泽温室气体排放的短期影响

利用静态箱-气相色谱法,研究了火干扰对小兴安岭白桦沼泽生长季CH4、CO2和N2O排放的季节变化、源/汇功能的影响,以及其与环境因子的关系.结果表明:轻度火干扰使白桦沼泽的气温和地表温度升高1.8℃～3.9℃,水位下降6.3 cm;重度火干扰使气温和0～40 cm土壤温度升高1.4 ℃～3.8℃,水位下降33.9 cm.轻度火烧、未火烧样地CH4呈春季吸收、夏秋季排放,重度火烧样地则呈春夏季吸收、秋季排放;未火烧样地CO2呈夏季>秋季≈春季,火干扰样地呈夏季>秋季>春季;未火烧样地N2O呈春季>夏季>秋季,轻度火烧样地呈秋季>春季>夏季,重度火烧样地呈夏季>秋季≈春季.未火烧样地CO2通量与气温、地表温度呈显著正相关,轻度火烧样地CO2通量与气温、5～10 cm土壤温度和水位呈显著正相关,重度火烧样地CO2通量与5～40 cm土壤温度呈显著正相关.火干扰使其CHM4排放量提高169.5%(轻度)或转变为弱吸收汇(重度),CO2和N2O排放量分别下降21.2%～34.7%和65.6%～95.8%,全球温暖潜势下降22.9%～36.6%.火干扰能够减少白桦沼泽温室气体排放,湿地管理实践中可适当开展有计划的火烧.     

火干扰对小兴安岭草丛、灌丛沼泽温室气体短期排放的影响

利用静态箱-气相色谱法,研究了火烧干扰对小兴安岭草丛、灌丛沼泽生长季CH4、CO2、N2O排放的季节变化及影响因子结果表明:火干扰使草丛、灌丛沼泽生长季的平均气温和各层土壤温度提高0.1—2.0℃,水位平均下降2.7 cm。火干扰使草丛、灌丛沼泽样地CH4排放通量提高了56%、524.9%,CO2排放通量分别下降了57.3%、14.5%,N2O排放通量分别下降27.1%,64.9%。火烧前后草丛沼泽CH4、N2O与灌丛沼泽CO2排放通量季节性规律未发生变化。火干扰改变了草丛沼泽生长季CO2、灌丛沼泽N2O排放通量的季节性变化规律。草丛沼泽对照样地CH4排放通量与5 cm土壤温度存在显著相关性,草丛沼泽CH4排放通量与水位相关性不显著。灌丛沼泽CH4排放通量与各层土壤温度及水位均无显著相关性。草丛、灌丛沼泽对照样地土壤CO2排放通量与0—15 cm土壤温度呈显著或极显著正相关,火烧样地与0—30 cm土壤温度呈显著或极显著正相关。草丛、灌丛沼泽对照、火烧样地土壤CO2排放通量与水位极显著负相关。火干扰使草丛、灌丛沼泽CH4排放源的强度增强,CO2、N2O的排放消弱,全球温室潜势下降约为23.3%。火干扰能够减少草丛、灌丛沼泽温室气体排放。     

黑土稻田CH4与N2O排放及减排措施研究

通过对黑土稻田CH₄和N₂O排放的观测,发现水稻生长季CH₄和N₂O排放量低于全国其它地区稻田CH₄和N₂O排放之间存在互为消长关系(r=-0．513,P<0．05),但在同样施肥水平条件下,间歇灌溉与长期淹灌相比,CH₄排放明显减少而N₂O略有增加,其相对综合温室效应被大大减少且水稻产量未受影响。为此,间歇灌溉可作为减少稻田温室气体排放的水分管理措施。另外,通过对CH₄和N₂O排放的相关微生物过程探讨,揭示产甲烷菌数与CH4排放问呈显著性正相关(R²=0．82,P<0．05),硝化菌数和反硝化菌数与N2O排放有重要关系。     

不同恢复方式下大兴安岭重度火烧迹地林地土壤温室气体通量

为研究大兴安岭重度火烧迹地在不同恢复方式下林地土壤CO₂、CH₄和N₂O排放特征及其影响因素,采用静态箱/气相色谱法,在2017年生长季（6月-9月）对3种恢复方式（人工更新、天然更新和人工促进天然更新）林地土壤温室气体CO₂、CH₄、N₂O通量进行了原位观测。研究结果表明：（1）3种恢复方式林地土壤在生长季均为大气CO₂、N₂O的源,CH₄的汇;生长季林地土壤CO₂排放通量大小关系为人工促进天然更新（（634.40±246.52）mg m^-2 h^-1） > 人工更新（（603.63±213.22）mg m^-2 h^-1） > 天然更新（（575.81±244.12）mg m^-2 h^-1）,3种恢复方式间无显著差异;人工更新林地土壤CH₄吸收通量显著高于人工促进天然更新;天然更新林地土壤N₂O排放通量显著高于其他两种恢复方式。（2）土壤温度是影响3种恢复方式林地土壤温室气体通量的关键因素;土壤水分仅对人工更新林地土壤N₂O通量有极显著影响（P < 0.01）;3种恢复方式林地土壤CO₂通量与大气湿度具有极显著的响应（P < 0.01）;土壤pH仅与天然更新林地土壤CO₂通量显著相关（P < 0.05）;土壤全氮含量仅与人工促进天然更新林地土壤CH₄通量显著相关（P < 0.05）。（3）基于100年尺度,由3种温室气体计算全球增温潜势得出,人工促进天然更新（1.83×10⁴ kg CO₂/hm²） > 人工更新（1.74×10⁴ kg CO₂/hm²） > 天然更新（1.67×10⁴ kg CO₂/hm²）。（4）阿木尔地区林地土壤年生长季CO₂和N₂O排放量为8.85×10⁶ t和1.88×10² t,CH₄吸收量为1.05×10³ t。     

不同水位管理对恢复泥炭地土壤CO2、CH4排放的影响

泥炭地水文条件影响泥炭地生物地球化学循环,控制和维持着泥炭地生态系统的结构和功能,是泥炭地生态恢复的重要前提。然而,目前关于恢复泥炭地土壤碳排放对不同水位的响应尚不明确。以长白山区天然（NP）、退耕（DP）及实施不同水文管理的恢复泥炭地（低水位（LR）、高水位（HR）与高低交替水位（H-LR））为研究对象,采用静态箱-气相色谱法对研究区泥炭地进行生长季（6-10月）土壤CO₂、CH₄排放监测。结果表明：温度和水位变化是研究区泥炭地土壤CO₂、CH₄排放季节变化的主控因子。H-LR受水位控制的影响,生长季土壤CO₂排放速率波动剧烈,其它水位管理恢复区土壤CO₂排放速率呈单峰型排放模式,且均与近地表温度呈指数相关（P<0.05）。除HR外,土壤CO₂排放速率与水位呈显著负相关（P<0.05）。生长季,研究区HR土壤CH₄排放速率呈双峰型,H-LR与NP的土壤CH₄排放呈单峰型,与近地表温度呈指数相关（P<0.05）,LR水位与CH₄排放速率显著正相关（P<0.05）。研究区不同水位管理恢复泥炭地土壤碳排放差异显著,虽然HR的土壤CO₂-C累积碳排放量显著低于其它水位恢复区,但其土壤CH₄-C累积碳排放量和综合增温潜势显著高于其它水位恢复区（P<0.05）。LR的累积碳排放量显著低于退化泥炭地,且其综合增温潜势最低。因此,建议在泥炭地恢复初期将低水位管理作为短期策略,以更好地恢复泥炭地碳汇功能,减弱其增温潜势。     

双季稻田种植不同冬季作物对甲烷和氧化亚氮排放的影响

研究双季稻收获后填闲种植不同冬季作物在其生长季节内CH₄和N₂O的排放特征,对合理利用冬闲稻田,发展冬季作物生产及合理评价不同种植模式具有重要意义。采用静态箱-气相色谱法对冬季免耕直播黑麦草、紫云英、油菜以及翻耕移栽油菜和冬闲的双季稻田中甲烷(CH₄)和氧化亚氮(N₂O)排放进行了分析。结果表明:在冬季作物生长期,CH₄、N₂O平均排放通量和总排放量均表现为翻耕移栽油菜＞免耕直播黑麦草＞免耕直播油菜＞免耕直播紫云英＞冬闲。不同冬季作物稻田CH₄和N₂O总排放量与对照(冬闲)的差异均达到极显著水平(P<0.01);翻耕移栽油菜的双季稻田中CH₄和N₂O排放量最高,分别达2.989 g/m²和0.719 g/m²。翻耕移栽油菜稻田的CH₄和N₂O温室效应总和也最大,为2893.92 kg CO₂/hm²;免耕直播黑麦草和免耕直播油菜处理次之,而免耕直播紫云英处理最低。种植不同冬季作物促进了稻田生态系统CH₄和N₂O的排放。     

火干扰对小兴安岭毛赤杨沼泽温室气体排放动态影响及其影响因素

利用静态箱-气相色谱法,对小兴安岭轻度火烧毛赤杨沼泽CH4、CO2、N2O生长季排放通量进行研究.结果表明:火烧使毛赤杨沼泽生长季CH4排放通量提高485.2％,CO2和N2O排放通量分别下降45.5％、24.8％.火烧未改变CH4季节性排放规律,但改变了CO2、N2O季节性变化规律.火烧样地CH4排放通量与土壤15cm温度间存在显著正相关性关系而与水位相关性不显著,火烧样地CO2排放与土壤0-30 cm温度呈显著或极显著正相关,与水位极显著负相关.对照样地CO2排放通量与土壤0-15 cm温度呈显著或极显著正相关,与水位极显著负相关,火烧使毛赤杨沼泽CH4排放源的强度增强,CO2、N2O的排放消弱,全球温室潜势下降约为43.34％.     

小兴安岭典型草丛沼泽湿地CO2、CH4和N2O的排放动态及其影响因素

 2007年6~10月, 采用静态箱-气相色谱法, 同步研究了小兴安岭典型修氏苔草(Carex schmidtii)沼泽湿地CO₂、CH₄和N₂O排放通量的季节动态及其与环境因子的关系, 估算了CO₂、CH₄和N₂O的生长季排放量, 探讨了沼泽湿地碳与氮的源汇关系。结果表明: 草丛沼泽生长季节温室气体排放量以CO₂占绝对优势(99.61%), CH₄的排放量次之(0.39%), N₂O的排放量最低(0.000 7%), 且为碳、氮的吸收汇(分别为固定量的53.93%和0.04%); CO₂、CH₄和N₂O生长季平均排放通量依次为487.89、1.88和0.004 mg·m^–2·h^–1, 且具有明显的季节变化特征, CO₂和N₂O的最高排放量均出现在夏季(6月24日至8月14日和7月14日至8月14日), CH₄的最高排放量出现在夏秋季(8月24日至9月24日), 其中, CO₂季节变化与空气温度和0~20 cm土壤温度具有显著相关性(p < 0.05), CH₄与空气温度具有显著相关性(p < 0.01), N₂O与水位具有显著的负相关性(p < 0.05)。     

城市小型景观水体CO2与CH4排放特征及影响因素

淡水生态系统被认为是大气温室气体排放的重要来源,尤其在人类活动影响下,其排放强度可能进一步增强。城市小型景观水体是城市生态系统的重要组成,具有面积小、数量大以及人类干扰强的特征,其温室气体排放特征及影响因素尚不清楚。选择重庆市大学城8个景观水体和周边2个自然水体为对象,于2019年1、4、7、10月,利用漂浮箱和顶空法分析了水体CO₂与CH₄的溶存浓度及排放通量,旨在揭示城市小型景观水体CO₂与CH₄排放强度、时空变异特征以及影响因素。结果表明,10个小型水体CO₂、CH₄的溶存浓度范围分别为10.75-116.25 μmol/L和0.09-3.61 μmol/L（均值分别为（47.6±29.3）μmol/L、（1.13±0.56）μmol/L）,均为过饱和状态;漂浮箱法实测的8个景观水体CO₂和CH₄排放通量均值分别为（72.7±65.9）mmol m^-2 d^-1和（2.31±3.48）mmol m^-2 d^-1（顶空法估算值为（69.7±82.0）mmol m^-2 d^-1和（3.69±2.92）mmol m^-2 d^-1）,是2个自然水体的3.5-6.1和2.0-4.5倍,呈较强的CO₂、CH₄排放源;居民区景观水体CO₂和CH₄排放略高于校园区,均显著高于对照的自然水体;CO₂排放夏季最高,秋季次之,冬、春季最低,CH₄呈夏季>秋季≈春季>冬季的季节模式,温度和水体初级生产共同影响CO₂和CH₄排放的季节模式;水生植物分布对景观水体CO₂、CH₄排放有显著影响,有植物分布的水域比无植物水域平均高1.97和2.94倍;漂浮箱法和顶空法测得气体通量线性关系较好,但顶空法测得CO₂通量在春季明显偏低,而CH₄则普遍偏高。相关分析表明,景观水体碳、氮浓度、pH值以及DO等对CO₂排放具有较好的指示性,CH₄排放通量主要与水体中碳、磷浓度有关。城市小型景观水体CO₂、CH₄排放通量远高于大部分已有自然水体的研究结果,呈一种较强的大气温室气体排放源,在区域淡水系统温室气体排放清单中具有重要贡献,未来研究中应给以更多关注。     

华南丘陵区冬闲稻田二氧化碳、甲烷和氧化亚氮的排放特征

采用静态箱 气相色谱法对收获后冬闲稻田CO₂、CH₄和N₂O排放进行了田间原位测定,探讨了越冬稻田3种温室气体的排放规律.结果表明,残茬稻田和裸田的CO₂的排放峰值分别出现在18:00和16:00左右.日间CH₄排放为净值,夜间表现为弱吸收.残茬稻田和裸田N₂O夜间排放分别为日间平均的1.79和1.58倍.残茬稻田的昼夜CO₂平均排放通量显著高于裸田(P＜0.05).在测定期间,残茬稻田CO₂排放随温度升高而增高.相关分析表明,CO₂排放与土温、地表温度和气温均呈显著相关,表明温度是影响收获后稻田CO₂排放的主要因素.在11月10日至翌年1月18日测定期间,残茬稻田的CO₂和CH₄平均排放通量分别为(180.69±21.21) mg·m^-2·h^-1和(-0.04±0.01) mg·m^-2·h^-1,CO₂排放通量较裸田高13.06％,CH₄吸收增高50%.残茬稻田的N₂O排放通量为(21.26±19.31) μg·m^-2·h^-1,较裸田低60.75％.由此说明华南丘陵区冬闲稻田是大气CO₂和N₂O的源,CH₄的汇.     

Identification key for European strand-forming house-rot fungi

An identification key for 20 common strand-forming indoor wood decay fungi is given. The key is based on observations of material from affected buildings and on wood samples that have been incubated in the laboratory. The key is with macro- and microscopic photographs.     

Plant-Parasitic Nematodes of South Viet Nam

Between 1974 and 1978, 2,842 identifications of plant-parasitic nematodes were made from more than 1,700 soil and plant samples collected in eight provinces of South Viet Nam. Species in nine genera—Helicotylenchus, Criconemoides, Meloidogyne, Pratylenchus, Tylenchorhynchus, Hoplolaimus, Hirschmanniella, Xiphinema, and Rotylenchulus—comprised 96.1% of the identifications; the remaining 3.9% were species of 11 genera. Fourteen genera were associated with rice which was grown on about 2,500,000 ha in 1970. Of these, Ditylenchus, Hirschmanniella, and Meloidogyne were most important. Ditylenchus angustus caused severe damage to about 50,000 ha of flooded rice in the Mekong Delta in 1976. Hirschmanniella spp. were found in all samples examined from flooded rice fields. Meloidogyne spp. were common in rice seedbeds, upland rice, and rice not kept flooded continuously. Meloidogyne and Pratylenchus spp. were found in roots of 22 of the 32 crop plants sampled. Little or no attempt was made in South Viet Nam to control nematodes.     

Semicircular canal system in early primates

Mammals with more rapid and agile locomotion have larger semicircular canals relative to body mass than species that move more slowly. Measurements of semicircular canals in extant mammals with known locomotor behaviours can provide a basis for testing hypotheses about locomotion in fossil primates that is independent of postcranial remains, and a means of reconstructing locomotor behaviour in species known only from cranial material. Semicircular canal radii were measured using ultra high resolution X-ray CT data for 9 stem primates (“plesiadapiforms”; n = 11), 7 adapoids (n = 12), 4 omomyoids (n = 5), and the possible omomyoid Rooneyia viejaensis (n = 1). These were compared with a modern sample (210 species including 91 primates) with known locomotor behaviours. The predicted locomotor agilities for extinct primates generally follow expectations based on known postcrania for those taxa. “Plesiadapiforms” and adapids have relatively small semicircular canals, suggesting they practiced less agile locomotion than other fossil primates in the sample, which is consistent with reconstructions of them as less specialized for leaping. The derived notharctid adapoids (excluding Cantius) and all omomyoids sampled have relatively larger semicircular canals, suggesting that they were more agile, with Microchoerus in particular being reconstructed as having had very jerky locomotion with relatively high magnitude accelerations of the head. Rooneyia viejaensis is reconstructed as having been similarly agile to omomyids and derived notharctid adapoids, which suggests that when postcranial material is found for this species it will exhibit features for some leaping behaviour, or for a locomotor mode requiring a similar degree of agility.     

Unification of the genera Nonlabens, Persicivirga, Sandarakinotalea and Stenothermobacter into a single emended genus, Nonlabens, and description of Nonlabens agnitus sp. nov

Phylogenetic analyses based on 16S rRNA gene sequences showed that a bacterial isolate, designated JC2678(T), represents a distinct phyletic line within the suprageneric monophyletic clade containing the genera Nonlabens, Persicivirga, Stenothermobacter and Sandarakinotalea. The polyphasic data presented in this study demonstrated that the members belonging to the Nonlabens-like clade overall constitute a single genus. Therefore, it is proposed to transfer the members of genera Persicivirga O'Sullivan et al. 2006, Stenothermobacter Lau et al. 2006 and Sandarakinotalea Khan et al. 2006 to the genus Nonlabens Lau et al. 2005. Thus, P. dokdonensis (Yoon et al. 2006) Nedashkovskaya et al. 2009, P. ulvanivorans Barbeyron et al. 2010, P. xylanidelens O'Sullivan et al. 2006, Sandarakinotalea sediminis Khan et al. 2006 and Stenothermobacter spongiae Lau et al. 2006 should be transferred to Nonlabens dokdonensis comb. nov., Nonlabens ulvanivorans comb. nov., Nonlabens xylanidelens comb. nov., Nonlabens sediminis comb. nov. and Nonlabens spongiae comb. nov., respectively. In addition, strain JC2678(T) (=KACC 14155(T)=JCM 17109(T)) is proposed to constitute a novel species belonging to the genus Nonlabens with the name of Nonlabens agnitus sp. nov.     

Two common and problematic leucochrysine species – Leucochrysa (Leucochrysa) varia (Schneider) and L. (L.) pretiosa (Banks) (Neuroptera,Chrysopidae): redescriptions and synonymies

We dedicate this article to the memory of Sergio de Freitas, FCAV-UNESP, Jaboticabal, São Paulo, Brazil (deceased, 2012). He was an active and enthusiastic Neuropterist and the cherished mentor and friend of Francisco Sosa.Leucochrysa McLachlan is the largest genus in the Chrysopidae, yet it has received relatively little taxonomic attention. We treat two problematic and common Leucochrysa species – Leucochrysa (Leucochrysa) varia (Schneider, 1851) and Leucochrysa (Leucochrysa) pretiosa (Banks, 1910). Both are highly variable in coloration and were described before the systematic importance of chrysopid genitalia was recognized. Recent studies show that these species occur within a large complex of cryptic species and that they have accumulated a number of taxonomic problems. We identify new synonymies for each of the species–for Leucochrysa (Leucochrysa) varia: Leucochrysa (Leucochrysa) ampla (Walker, 1853), Leucochrysa internata (Walker, 1853), and Leucochrysa (Leucochrysa) walkerina Navás, 1913; for Leucochrysa (Leucochrysa) pretiosa: Leucochrysa (Leucochrysa) erminea Banks, 1946. The synonymy of Leucochrysa delicata Navás, 1925 with Leucochrysa (Leucochrysa) pretiosa is stabilized by the designation of a neotype. The following species, which were previously synonymized with Leucochrysa (Leucochrysa) varia or Leucochrysa (Leucochrysa) pretiosa, are reinstated as valid: Leucochrysa (Leucochrysa) phaeocephala Navás, 1929, Leucochrysa (Leucochrysa) angrandi (Navás, 1911), and Leucochrysa (Leucochrysa) variata (Navás, 1913). To help stabilize Leucochrysa taxonomy, lectotypes are designated for Allochrysa pretiosa and Allochrysa variata. Finally, Leucochrysa vegana Navás, 1917 is considered a nomen dubium.     

Annotated checklist of the recent and extinct pythons (Serpentes, Pythonidae), with notes on nomenclature, taxonomy, and distribution

McDiarmid et al. (1999) published the first part of their planned taxonomic catalog of the snakes of the world. Since then, several new python taxa have been described in both the scientific literature and non-peer-reviewed publications. This checklist evaluates the nomenclatural status of the names and discusses the taxonomic status of the new taxa, and aims to continue the work of McDiarmid et al. (1999) for the family Pythonidae, covering the period 1999 to 2010. Numerous new taxa are listed, and where appropriate recent synonymies are included and annotations are made. A checklist and a taxonomic identification key of valid taxa are provided.