Distinguishing the effects of vegetation restoration on runoff and sediment generation on simulated rainfall on the hillslopes of the loess plateau of China

Aims

Since the 1970s, extensive croplands were converted to forest and pasture lands to control severe soil erosion on the Loess Plateau of China. We quantify the direct and indirect effects of vegetation restoration on runoff and sediment yield on hillslopes in the field to improve environmental governance.

Methods

An artificial rainfall experiment at a rainfall intensity of 120 mm h⁻¹ and a slope gradient of 22° were used to distinguish the effects of vegetation restoration on runoff and sediment yield.

Results

Compared to the farmland slopes, vegetation restoration directly prolonged the time-to-runoff by 140%, reduced the runoff rate by 20%, and increased the soil infiltration capacity by 15%. Vegetation restoration indirectly delayed the time-to-runoff by 120%, reduced the runoff rate and sediment yield rate by 50% and 94%, respectively, and increased the soil infiltration capacity by 58% on the hillslopes with vegetation restoration.

Conclusions

The direct effects of vegetation restoration on runoff and sediment yield were lower than its indirect impacts. Vegetation cover, decreases in soil bulk density, and increases in belowground root biomasses and > 0.25 mm aggregate stability were the primary causes of runoff and sediment yield reduction on the slopes with vegetation restoration.

     

NEW ARRENURUS SPECIES (ACARI,HYDRACHNELLAE, ARRENURIDAE) FROM SOUTHERN AFRICA

SUMMARY

Five new Arrenurus spp, from Southern Africa are described: A. amoenus sp. nov. from Natal, A. agnewi sp. nov., A. curtipalpus sp. nov., A. pedatus sp. nov. and A. cavatus sp. nov. from Botswana. The species from Natal came from an older collection belonging to the National Institute for Water Research. The species from Botswana were collected recently by Dr J.D. Agnew¹

The water mite fauna of South Africa is only partly known. Therefore it is important that collectors should know that alcohol and formalin are not suitable fixatives. Fixing and storing is most successful in the following mixture: 5 parts glycerin, 2 parts glacial acetic acid and 3 parts water.     

TURBIDITY AND OTHER PHYSICAL FACTORS IN NATAL ESTUARINE SYSTEMS PART 1: SELECTED ESTUARIES

SUMMARY

Data on turbidity and the factors influencing it, such as wind and substratum, were collected from eight representative estuaries along the Natal Coast. The results showed that Natal Estuaries can be divided into one of four groups, according to the turbidity regime present in the system, as either Clear (<10 Nephelometric Turbidity Units = NTU), Semi Turbid (10–50 NTU), Predominantly Turbid (51–80 NTU) and Very Turbid (>80 NTU). The influence of the tidal cycle on turbidity, salinity and temperature was also investigated. It was found that tidal action often creates gradients within a system. Turbidity gradients were more frequent in occurrence than either salinity or temperature gradients.     

A novel predictive algorithm to personalize autologous T-cell harvest for chimeric antigen receptor T-cell manufacture

Background aimsThe most widely accepted starting materials for chimeric antigen receptor T-cell manufacture are autologous CD3+ T cells obtained via the process of leukapheresis, also known as T-cell harvest. As this treatment modality gains momentum and apheresis units struggle to meet demand for harvest slots, strategies to streamline this critical step are warranted.MethodsThis retrospective review of 262 T-cell harvests, with a control cohort of healthy donors, analyzed the parameters impacting CD3+ T-cell yield in adults with B-cell malignancies. The overall aim was to design a novel predictive algorithm to guide the required processed blood volume (PBV) (L) on the apheresis machine to achieve a specific CD3+ target yield.ResultsFactors associated with CD3+ T-cell yield on multivariate analysis included peripheral blood CD3+ count (natural log, ×10⁹/L), hematocrit (HCT) and PBV with coefficients of 0.86 (95% confidence interval [CI], 0.80–0.92, P < 0.001), 1.30 (95% CI, 0.51–2.08, P = 0.001) and 0.09 (95% CI, 0.07–0.11, P < 0.001), respectively. The authors’ model, incorporating CD3+ cell count, HCT and PBV (L), with an adjusted R² of 0.87 and root-mean-square error of 0.26 in the training dataset, was highly predictive of CD3+ cell yield in the testing dataset. An online application to estimate PBV using this algorithm can be accessed at https://cd3yield.shinyapps.io/cd3yield/.ConclusionsThe authors propose a transferrable model that incorporates clinical and laboratory variables accessible pre-harvest for use across the field of T-cell therapy. Pending further validation, such a model may be used to generate an individual leukapheresis plan and streamline the process of cell harvest, a well-recognized bottleneck in the industry.     

黄河河龙区间退耕还林前后淤地坝拦沙特征分析

为探究黄河中游河龙区间退耕还林工程实施前后淤地坝拦沙变化特征,采用实地测量和文献集成分析相结合的方法,分析了退耕前后多个时段河龙区间不同分区淤地坝的拦沙特征。结果表明:退耕后,河龙区间北部、中部和南部淤地坝平均拦沙模数分别为7138.5 t km~(-2) a~(-1)、2596.5 t km~(-2) a~(-1)和4230.9 t km~(-2) a~(-1),比退耕前分别减少了49.5%、84.1%和52.1%,且均显著小于退耕前,坝控流域侵蚀程度总体上由极强烈侵蚀、剧烈侵蚀和极强烈侵蚀分别转变为强烈侵蚀、中度侵蚀和中度侵蚀;退耕前河龙区间中部和南部淤地坝拦沙模数随时间推进显著降低;退耕后河龙区间北部淤地坝拦沙模数随时间推进而下降。未来河龙区间淤地坝建设应根据小流域侵蚀产沙现状适当缩减规模,以免造成水土资源浪费,影响下游的用水安全。     

Temperature acclimation in Actinia equina L. (Anthozoa)

Respiratory adaptation to different sea temperatures on the Natal (east) and Table Bay (west) coasts of southern Africa is demonstrated in Actinia equina L. Animals are able to acclimate to lower sea temperatures but are unable to adapt to an increase of 3 °C or more above summer sea temperatures. Acclimation to elevated water temperatures may be limited by thermal sensitivity of the tissues and by lack of feeding when under thermal stress.The successful colonization of the Natal littoral zone by A. equina may be attributed partially to metabolic adaptability but also to its brooding ability, tolerance of desiccation, and capacity to retain water within the coelenteron. Slow exudation of this water enables evaporative cooling of the tissues during low tide. Other actinian species from Natal lack this range of features and are hence limited to damp habitats at lower tidal levels.     

Effects of Bradyrhizobium strain and host genotype,nodule dry weight and leaf area on groundnut (Arachis hypogaea L. ssp. fastigiata) yield

Effects of inoculating four Arachis hypogaea ssp. fastigiata cultivars with 17 Bradyrhizobium spp. strains were studied in a glasshouse experiment using a sandy soil devoid of an indigenous Bradyrhizobium population. Firstly, a wide range of parameters, indicative of symbiotic performance, were assessed for their influence on seed yield, by correlation and statistical analyses. It was found that nodule dry weight and leaf area were relevant parameters concerning seed yield. Secondly, the effects of host and strain genotype on those parameters were described.Variations in nodule dry weight did not have an effect on seed yield, except for cultivar Natal Common at lower nodule dry weight values. Therefore, it was concluded that the quantity of nitrogen fixing tissue met the demand for combined nitrogen and did not limit seed yield. This conclusion was further supported by the observation that at low nodule numbers per plant the nodule size increased to generate sufficient nitrogen fixing tissue.Leaf area, which comprises components for both photosynthetic capacity and plant development, was found to correlate well with seed yield. An increase in leaf area resulted in significant seed yield increases for all three spanish-type cultivars, but not for the valencia-type cultivar. Leaf area, thus, appeared as a factor limiting seed yield of spanish-type groundnuts.Cultivar performance concerning seed yield was significantly better for Natal Common compared to the other three cultivars, while Natal Common had a significantly lower plant (biomass excluding seed) dry weight value.Inoculation with different strains of Bradyrhizobium resulted in significantly different nodule dry weight values, but hardly led to significant differences in seed yield. This agreed with the finding that the amount of nitrogen fixing tissue appeared not to limit the availability of combined nitrogen.A large quantity of nitrogen was partitioned to the groundnut seeds: 62% to 76% of total accumulated nitrogen was located in the seeds.This study showed that testing for symbiotic effectiveness in the groundnut Bradyrhizobium symbiosis should include assessment of final (seed and biomass) yield, because parameters measured at stages prior to maturity, like nodulation parameters, may lead to flawed effectiveness ratings.     

一株聚羟基脂肪酸酯合成菌的筛选及鉴定

【背景】传统石油基塑料产品给人类和环境带来的危害日益严重,聚羟基脂肪酸酯(polyhydroxyalknoates,PHA)作为新型可降解塑料原料越来越受到青睐。但PHA生产成本过高,使其推广应用严重受限。筛选适合大规模生产PHA的高产菌株是解决这一问题的重要途径。【目的】以挖掘合成PHA的菌种资源为目标,从极端环境筛选和鉴定新的高产PHA合成菌。【方法】通过尼罗蓝平板分离法和PCR法分离纯化菌株,采用16S rRNA基因鉴定并通过MEGA 6.0软件构建系统发育树,分析菌株的进化关系,最后通过尼罗红染色定性分析和气相色谱法定量测定该菌株在不同时期的PHA积累量。【结果】从盐碱地垃圾沉积物中分离得到了一株高产PHA的菌株,PhaC的PCR扩增结果证实了该菌株是PHA合成菌,经16S rRNA基因鉴定为Pseudomonas brassicacearum,将其命名为NP-2,进一步优化了菌株NP-2的培养条件,在培养48h时PHA积累量最大,达到3.78 mg/mL。【结论】NP-2属于Pseudomonas brassicacearum,能高产PHA。本研究为生产PHA提供了极端环境的...     

Species of natural hybrid origin and misinformation in the Irises: A reappraisal of the presence of I. aphylla L. in Italy

Abstract

The identity and status of the records of Iris aphylla L. for Italy are reconsidered. The authors are of the opinion that I. perrieri Simonet ex N. Service, present in Savoy, France, is genetically and morphologically distinct from I. aphylla, and that the Italian populations from Piemonte are in fact conspecific with I. perrieri. In addition, we consider that another iris, I. benacensis A. Kern. ex Stapf , which occurs near Lago di Garda (Mt. Brione) and is often also regarded as a synonym of I. aphylla, is not conspecific with either I. aphylla or I. perrieri. Macro-, micro-morphological and biosystematic data obtained during this investigation suggest a possible natural hybrid origin of these species and confirm the opinion of the authors, which is justified also by the different chromosome numbers and distribution of the taxa examined.     

Wetland Plant Species Used for Craft Production in Kwazulu–Natal,South Africa: Ethnobotanical Knowledge and Environmental Sustainability

Wetland Plant Species Used for Craft Production in Kwazulu–Natal, South Africa: Ethnobotanical Knowledge and Environmental Sustainability. In KwaZulu–Natal Province, there is a rich tradition of wetland plant utilization for craft production. A survey of the province, based on interviews and participatory field walks, revealed which wetland plant species are harvested and how the different species are used. The principal plant species utilized varied greatly among regions: In the coastal region it was Cyperus latifolius Poir. (iKhwane) and Juncus kraussii Hochst. (iNcema), whereas in the uplands it was Cyperus marginatus Thunb. (iNcema). The initial hypothesis that the diversity of plant morphologies added to the diversity of different weave types and products was confirmed by the data. Plant morphological characteristics influenced the weaving techniques suitable for craft production. For example, the fine culms of J. kraussii and C. marginatus have particular value for twilling, twining, and straight sewing and the robust C. latifolius leaves are well suited for the plait. Pressures on the supply of the natural resource were greatest from competing land uses, such as wetland cultivation and, to a lesser extent, from competition among plant harvesters. There was a high demand for J. kraussii, which is traded beyond the limits of its geographical distribution to a much greater extent than the other species. The paper concludes by recommending the wider application of the approach and methods used in the study in order to inform initiatives promoting small business development based upon sustainably harvested natural resources.     

WETLANDS AND AGRICULTURE

SUMMARY

Emphasis is given to the importance of wetlands and the need for a rational and multi-use approach to their development. Their occurence in the landscape is explained and a brief account is given of characteristic soils and other related features.

Wetlands are widely distributed in certain landscapes and generally have high agricultural potential, especially for the production of cultivated pastures. A large proportion of the vleis in Natal have already been developed.

Important principles and procedures to be considered in planning wetland development are presented. The urgent need to develop a wetland strategy, initiate appropriate research, apply effective legislation and identify wetlands in need of total protection is stressed.     

黄土丘陵区坡面植被盖度及其配置格局的水蚀效应模拟

黄土高原因土壤侵蚀严重被视为生态脆弱地带,探讨植被盖度及其所处坡位对土壤侵蚀的响应,对坡面侵蚀产沙的预测和调控具有重要意义。基于WEPP模型情景模拟,分析了分布广泛、耐旱性强的长芒草和典型恢复灌木植被柠条在不同雨强(0.5、1.0、1.5 mm/min)、不同植被盖度(20%、40%、60%、80%)和不同坡位(坡上、坡中、坡下)条件下的土壤侵蚀变化情况,运用双因素方差分析和相关贡献指数阐明坡面侵蚀产沙特征对坡位和植被盖度交互作用的响应,并提出植被配置的优化模式。结果表明:(1)提高植被有效覆盖度是减小土壤侵蚀的重要举措,且当植被分布在下坡位时坡面土壤侵蚀最少;(2)植被盖度可以有效减少产沙量。小雨强时,柠条和长芒草随盖度增加对泥沙的拦截率分别从38%增加到90%,64%增加到96%;中、大雨强时,植被盖度小于20%或者大于80%时,长芒草坡面产沙量大于柠条坡面。盖度为40%—60%时,长芒草坡面产沙量小于柠条坡面;(3)双因素方差分析表明:坡位和植被盖度对坡面侵蚀产沙量有极显著的影响(P0.001);当植被是长芒草时,坡位和植被盖度交互作用对坡面侵蚀产沙有显著影响(P0.01),植被是柠条时,坡位和植被盖度交互作用对坡面侵蚀产沙作用不显著;(4)通过模拟柠条和长芒草不同配置情景得出:长芒草分布在坡面下部产沙量较小,且当柠条和长芒草配比为1∶2时产沙量最小。     

Hemiuridae (Digenea) from marine fishes of the southern Indian Ocean: Genus Lecithochirium Lühe, 1901 (Lecithochiriinae)

The genus Lecithochirium is briefly discussed and a provisional key to species groups is presented. The following species are described, figured and/or recorded from regions of the southern Indian Ocean: Lecithochirium genypteri from Xiphiurus capensis, Cape Province; L. magnus from Gymnothorax woodwardi and G. javanicus, Western Australia; L. parafusiforme n. sp. from G. flavimarginatus, Natal (type-host and locality) and G. woodwardi, Western Australia; L. macrorchis from G. woodwardi; Leithochirium sp. (ghanense-group?) from Platycephalus bassensis, South Australia; L. kawakawa from Euthynnus affinis and Chrysoblephus anglicus, Natal; Lecithochirium sp. (synodi-group?) from Saurida undosquamis, Natal; L. gymnapisti n. sp. from Gymnapistes marmoratus, Western Australia; L. jaffense from Trachichthodes gerrardi, South Australia and Blennioclinus brachycephalus, Cape Province; Lecithochirium sp. (group unknown) from Alectis ciliaris, Natal.     

东太平洋多金属结核区两个站位深海沉积物细菌多样性北大核心CSCD

【目的】为了解东太平洋中国多金属结核勘探合同区西区2个站位(WBC1305和WBC1316A)深海沉积物细菌群多样性。【方法】直接提取环境样品总基因组,通过PCR和TA克隆策略构建了2个站位6个层次16S r RNA基因文库,对2个站位沉积物表层泥样中细菌多样性和群落结构特征进行分析,并通过构建系统发育树,进行系统发育学分析。【结果】2个站位6个文库共获得有效克隆533个,其中472个克隆包括α-变形菌纲、β-变形菌纲、γ-变形菌纲、δ-变形菌纲、浮霉菌门、酸杆菌门、硝化螺旋菌门、放线菌门、绿弯菌门、厚壁菌门、拟杆菌门、迷踪菌门、芽单胞菌门、Hydrogenedentes、Chlorobi和Nitrospinae16个细菌类群,而另外61个克隆为不可分类细菌类群。【结论】结果表明γ-变形菌纲和厚壁菌门分别是WBC1305和WBC1316A站位的优势种群;WBC1316A站位细菌群落结构更加丰富和复杂。     

黄土丘陵区生物结皮坡面产流产沙与其分布格局的关联

生物结皮在黄土丘陵区退耕地广泛发育,并在干扰等因素下形成不同分布格局。为明确生物结皮分布格局对坡面产流产沙的影响,采用模拟降雨试验研究了生物结皮条带状、棋盘状和随机3种分布格局对坡面产流产沙的影响,借助景观生态学方法,计算了生物结皮斑块的分布格局指数,解析了生物结皮分布格局与坡面产流产沙的关联。结果表明,（1）生物结皮分布格局显著影响坡面初始产流时间、径流率和土壤侵蚀速率。相同盖度条件下,生物结皮坡面的随机分布格局较带状和棋盘式分布格局显著降低了坡面径流量和产沙量,其径流率与土壤侵蚀速率分别是带状格局的71.7%、12.9%,是棋盘格局的89.6%、31.8%。（2）坡面径流率与生物结皮斑块最大斑块指数、斑块连结度呈极显著负相关,与分离度呈极显著正相关,与景观分裂指数呈显著正相关。（3）土壤侵蚀速率与生物结皮斑块最大斑块指数、斑块连结度呈显著负相关,与景观分裂指数、分离度呈显著正相关。（4）坡面径流率（Y₁）和土壤侵蚀速率（Y₂）与分离度（SPLIT,Splitting Index）的关系式为：Y₁=1.116+0.017SPLIT,R²：0.957;Y₂=22.767+17.936SPLIT,R²：0.801。（5）以上结果表明分布格局主要是通过影响生物结皮在坡面的分离度进而影响坡面产流产沙,随着生物结皮斑块分离度增大,生物结皮斑块破碎度增大,坡面产流产沙增多。从分布格局的角度解析了生物结皮对产流、产沙的影响,量化了生物结皮坡面径流率与侵蚀率与格局指数之间的关系,为量化认识生物结皮的水土保持功能提供了科学依据。     

内蒙古岗更诺尔湖泊退化情景下好氧甲烷氧化的微生物过程研究

【目的】内蒙古岗更诺尔湖退化为碱地、草地情景下,研究好氧甲烷氧化过程及其微生物群落的变化规律。【方法】针对湖泊沉积物及其退化后形成的碱地、草地土壤,在不同初始甲烷浓度下培养,研究其甲烷氧化速率,通过实时荧光定量PCR、高通量测序技术分析甲烷氧化菌的群落构成及其变化规律。【结果】湖泊退化过程中,沉积物和碱地的土壤理化性质、甲烷氧化速率变化规律基本一致,但与草地土壤有显著差异。在微生物属水平,甲烷氧化菌Methylococcus的丰度显著增加,在沉积物、碱地和草地中的丰度分别为19.2%、48.8%和78.3%,而Crenothrix的丰度明显降低,依次为54.7%、32.1%、和13.9%。进一步室内模拟不同初始浓度下甲烷氧化过程,发现沉积物中Crenothrix和Methylocaldum的增幅最大;碱地土壤中Methylococcus和Methylomonas的增幅远高于其他甲烷氧化菌;而在草地土壤中,Crenothrix增加高达7.81%,增幅达196倍。这些显著增加的微生物可能在不同浓度甲烷氧化过程中发挥了重要作用。【结论】湖泊退化过程中,甲烷氧化潜力降低。沉积物中的甲烷氧化菌发生了显著分异,Methylococcus逐渐成为碱地和草地的优势微生物,而Crenothrix则逐渐成为弱势类群。然而,草地土壤氧化高浓度甲烷过程中,数量上占弱势的Crenothrix迅速变为优势类群,可能发挥了重要作用。     

THE DISTRIBUTION OF WETLANDS IN THE SOUTH-WESTERN CAPE PROVINCE,SOUTH AFRICA

Summary

The hydrological and habitat value of wetlands is beginning to be recognised in South Africa, but only in parts of Natal Province has an effort been made to map wetlands and to record their status over large areas. While the most accurate method of mapping wetlands is a combination of photogrammetry and field surveys, this is time-consuming and expensive. An alternative “desktop” method was therefore used to draw up a preliminary distribution of wetlands in the south-western Cape Province, and this approach consisted of summarising the information contained on 1:50 000 topographical survey maps. The summary shows that shallow, vegetated wetlands (vleis) occur mainly in the wetter south and south-west of the region, while the non-perennial wetlands (pans) predominate inland, where the land is dryer and flatter. There are many estuarine wetlands along the coast, resulting from the tendency of river mouths to be blocked by sand-bars. Farming requirements and suitable topography account for the many small artificial wetlands (farm dams) in the central southern parts. Farm dams predominate in the region (15067 were counted), followed by pans (1741), riverine wetlands (261), vleis (216) and estuarine wetlands (15).     

深渊沉积物中盐单胞菌(Halomonas sp.)NyZ771菌株的分离培养及其降解芳香酸的研究

【背景】海洋是地球上最大的碳库,也是地球生物最大的栖息地。在这个庞大的生态系统中拥有多种多样的微生物,它们在全球碳循环中扮演了重要的角色。海斗深渊(海平面6 000 m以下的海域)由于高静水压和表层沉积汇集了大量有机质,形成了包含丰富生物资源的特殊生境。【目的】从马里亚纳海沟海斗深渊沉积物样品中分离培养能够以芳香酸为唯一碳源和能源生长的微生物,并研究其降解特性。【方法】通过模拟原位高压环境富集培养和常压条件下芳香酸选择性分离培养获得深渊来源的纯培养细菌,并根据形态学观察和16S rRNA基因序列系统发育分析进行种属鉴定,利用不同芳香酸进行培养和生物转化,通过HPLC和LC/MS鉴定芳香酸代谢中间产物。【结果】从马里亚纳海沟6 300 m沉积物样本中分离获得了一株盐单胞菌(Halomonas sp.)NyZ771。该菌株能够利用苯甲酸和4-羟基苯甲酸作为唯一碳源生长。其代谢4-羟基苯甲酸的中间产物鉴定为原儿茶酸。【结论】从深渊沉积物样本分离得到一株能降解苯甲酸和4-羟基苯甲酸的盐单胞菌NyZ771,丰富了深渊来源的微生物资源,为今后研究深渊中微生物的芳香酸降解及海洋微生物驱动的碳循环提供了一定的理论基础。     

Redescription of <Emphasis Type="Italic">Neoscombrops cynodon</Emphasis> (Regan, 1921), a senior synonym of <Emphasis Type="Italic">Neoscombrops annectens</Emphasis> Gilchrist, 1922 (Perciformes: Acropomatidae)

Neoscombrops annectens Gilchrist, 1922, described from off Natal, South Africa, has long been regarded as a valid species. Although Acropoma cynodon Regan, 1921, also described from off Natal, was found to be Neoscombrops, they were regarded as distinct species, distinguishable by body depth and body color. Examination of many specimens, including the holotype of A. cynodon and neotype of N. annectens, revealed that the differences are within the range of intraspecific variation. N. cynodon is redescribed as a senior synonym of N. annectens.