春夏季长江口邻近水域仔稚鱼种类组成和丰度的月变化

利用2015年4—7月在长江口邻近水域的调查数据,对春夏季该水域仔稚鱼种类组成和丰度的月变化特征进行了观测。结果表明,共采获62种、35839尾仔稚鱼,分别属于14目、30科、45属。各月种类数范围为22~36种,从4月到6月,先是缓慢增加然后快速增加,至6月达到高峰期,7月则大幅降低。各月的丰度范围为11.45~114.31 ind/(100 m3);丰度随时间的推移而持续增加。各月主要种类数范围为5~13种,具有较大的波动性;优势种主要为小黄鱼(Larimichthys polyactis)、小公鱼属(Stolephorus sp.)、六丝矛尾虾虎鱼(Chaeturichthys hexanema)、鳀(Engraulis japonicus)、红狼牙虾虎鱼(Odontamblyopus rubicundus)、斑尾刺虾虎鱼(Acanthogobius ommaturus)、属(Callionymus sp.)等。优势种随时间推移表现出较大的更替性。种类数以20 m以浅水域最多,不同水深范围的月变化有一定的差异性。20 m以浅海域的种类数与表层水温的关系在4—6月为显著正相关(r=0.997,P0.05),6月到7月表现为相反的变化趋势;各月的丰度与表层盐度呈显著负相关(r=-0.91,P0.05)。从春季到夏季,仔稚鱼高丰度区从浅水区向深水区转移。     

主要人为排放源中氮氧化物~(15)N自然丰度的测定

氮氧化物(NO_x=NO+NO_2)因其对环境和人类健康的威胁,成为大气中需要严格控制的一种痕量组分。首次运用化学转化法,通过将主要人为排放源废气中的氮氧化物(NO_x)转化为氧化亚氮(N_2O),测定气体中NO_x的15N自然丰度,即氮稳定同位素比值(δ15N-NO_x)。利用酸性氧化剂将NO_x氧化为硝酸(NO_3~-),并通过三氯化钒(VCl_3)和叠氮钠(NaN_3)的共同作用将其转化为N_2O,利用带有自动预浓缩装置的稳定同位素比值质谱计(PT-IRMS)测定δ15N-NO_x。该方法的测量精度可达0.09‰,所需样品量仅为7μg(以氮计),对火力发电站、机动交通工具等人为排放源均适用,测量精度和准确度可满足NOx相关研究的需求。     

接种密度对植物生长及烃降解的影响

The combined use of plants and bacteria is a promising approach for the remediation of soil contaminated with organic pollutants. Different biotic and abiotic factors can affect the survival and activity of the applied bacteria and consequently plant growth and phytoremediation efficiency. The effect of inoculum density on the abundance and expression of alkane-degrading genes in the rhizosphere of plant vegetated in hydrocarbon-contaminated soil has been rarely observed. In this study, an alkane-degrading bacterium (Pantoea sp. strain BTRH79), at different inoculum densities (10⁵ to 10⁸ cells cm^-3 soil), was inoculated to ryegrass (Lolium perenne) vegetated in diesel-contaminated soil to find the optimum inoculum density needed for its efficient colonization and hydrocarbon degradation activity. Bacterial inoculation improved plant growth and hydrocarbon degradation. Maximum plant growth and hydrocarbon degradation wwereobserved with the inoculum having the highest cell density (10⁸ cells cm^-3 soil). Moreover, the inoculum with higher cell density exhibited more abundance and expression of alkane hydroxylase gene, CYP153. This study suggests that the inoculum density is one of the main factors that can affect bacterial colonization and activity during phytoremediation.     

捡拾牦牛粪对高寒草甸植物功能群特征与生产力的影响

青藏高原高寒草甸广大牧区由于交通不便、能源短缺和生活习俗等原因,牛粪依然是当地牧民的主要生活能源来源,长期、大量地捡拾牛粪改变了粪斑的数量和面积,使养分在天然草地上无法回到草地生态系统进行再循环,因而对草地植物群落结构和生物量产生一定影响,从而增加了生态风险。为探讨捡拾牛粪对草地的生态影响,本文以青海省河南县高寒草甸生态系统为研究对象,通过对适度放牧草地上牦牛粪开展为期3年的不捡拾、一半捡拾和全部捡拾3个处理的试验研究,探讨捡拾牛粪对高寒草甸生态系统植物经济功能群落特征和生产力的影响。结果表明:牛粪不捡拾处理的草地生产力显著低于半捡拾和全捡拾处理,植物多样性显著低于半捡拾处理,禾草类优良牧草生物量显著高于半捡拾和全捡拾处理,莎草类优良牧草生物量显著高于全捡拾处理;牛粪半捡拾处理比不捡拾处理草地植被丰富度显著提高31.9%,植物多样性显著增加,群落生产力显著提高9.7%(42.6 g·m~(-2)),优良牧草和可食牧草生物量变化不显著;牛粪完全捡拾比不捡拾处理也显著增加草地植被的丰富度,增幅为10.7%,植物多样性显著增加,群落生产力显著提高4.1%(17.96 g·m~(-2)),但同时毒杂草显著增多,优良牧草和可食性牧草显著减少,牧草适口性变差。捡拾(半捡和全捡)牛粪会使禾草类和莎草类优质牧草生物量显著减少,莎草类在完全捡拾牛粪区生物量极显著减少70%以上;豆科植物生物量显著增加,在完全捡拾牛粪区生物量极显著增加,可达5倍以上;占总生物量74%~79%的杂类草和毒草的生物量也显著增加,且以半捡拾区增量最多。适度的牛粪捡拾可增加植被的丰富度和多样性,也提高了植被的生物量,并可保证牧草的营养品质和适口性。本项研究结果可以为高寒草甸牧区牛粪的适度捡拾和草地生态系统可持续管理提供科学依据。     

Does the Intensity of Anisakis Infection Affect the Quality of Hake Muscle?

The distribution of Anisakis larvae in fresh caught hake was studied, and the influence of three infection levels of the viscera (low, medium, high) on quality changes of deep frozen muscle was followed over 220 days. Differences in quality were attributed more to the size of the individuals than to the infection degree of the three groups. The removal of belly flaps diminished the risk of consumers’ infection and sensitization as prevalence and intensity was reduced to 75.6 and 5.9%, respectively. Allergens were detected after 220 days frozen storage, which represents a risk for consumers already allergic to Anisakis.     

物种多度格局研究概况

 介绍了群落水平多度格局与物种水平多度格局,概述了国内群落多度格局应用研究状况。其中节肢动物群落多度格局研究最为丰富,许多学者利用节肢动物群落物种多度格局对栖境质量进行评价。国内由于多度分布模型的拟合比多样性指数的计算复杂且困难得多,远没有群落多样性研究广泛;国内的物种多度分布研究往往集中在用现有的模型去拟合目标群落的多度分布,缺乏在物种多度分布的研究尺度和抽样方法方面,以及多度分布机制和新模型探索等方面的深入研究。这些内容应该成为今后研究的重点。     

Comparison of litterfall and nutrient return in a Vaccinio uliginosi–Betuletum pubescentis and an Empetro nigri–Pinetum forest ecosystem in northern Poland

Litterfall abundance and composition of organic and inorganic nitrogen and phosphorus forms were studied for 34 months in two different forest ecosystems (Vaccinio uliginosi–Betuletum pubescentis (Vu–Bp) and Empetro nigri–Pinetum (En–P)) in S?owiński National Park (northern Poland). Including broadleaves, litterfall abundance in Vu–Bp was above 25% higher than in En–P. In Vu–Bp the mean litterfall abundance was equal to 4050 kg ha⁻¹ year⁻¹ with needles (31%) and broadleaves (32%) dominating while in En–P the mean litterfall abundance was equal to 2828 kg ha⁻¹ year⁻¹ and needless made up 59% of total. Almost all litterfall fractions in both forest ecosystems followed a clear, coherent seasonal pattern with maximal values in Autumn and minimal values in the growing season. In general, inter-annual fall variation of needles, branches, broadleaves and seeds was not significant in both ecosystems, however, for the fall of needles and branches a decreasing tendency was observed. In Vu–Bp and in En–P total litterfall (Vu–Bp: T-N 97.5%, N_org 96.8%, En–P: T-N 95.6%, N_org 97.9%) as well as the needless (Vu–Bp: T-N 31.9%, N_org 46.4%; En–P: T-N 53.5%; N_org 53.6%) were the most abundant with nitrogen with the supremacy of organic forms. Besides needles fall, the highest nitrogen return in Vu–Bp was contributed by broadleaves, seeds and branches fall, while in En–P with branches and bark fall. The lowest nitrogen return was contributed by inflorescences and flower buds fall. Similar to organic nitrogen, organic phosphorus was dominant in Vu–Bp (91%) and in En–P (77%) ecosystems. In Vu–Bp total phosphorus contributed by broadleaves was comparable to deposited with needles. In the fallen needless phosphorus contribution was significantly higher in En–P than in Vu–Bp. Nearly 40% of total phosphorus return was contributed by branches, seeds and other litterfall material in Vu–Bp. Litterfall mass in Vu–Bp showed positive correlation with air humidity, total nitrogen content in the rooting zone, and negative with underground water level and air temperature indicating lower resistance towards climatic stress. At both forest ecosystems total litterfall mass, total nitrogen and organic nitrogen were positively correlated with air humidity, while neither total litterfall, nor total nitrogen (T-N) and total phosphorus (T-P) at both forest ecosystems were correlated directly with precipitation volume. This is probably because air humidity is partially related to precipitation (r_Sp = 0.31), however it could be also an effect of sea sprays contribution. Homogeneous Pinus sylvestris stand indicates higher resistance towards unfavorable climatic conditions than Betula pubescens, and this is why it should be preferably used in afforestation campaigns in seashore.     

Forest management and temporal effects on food abundance for a ground-foraging bird (Catharus guttatus)

While food abundance is known to limit bird populations, few studies have simultaneously examined both temporal and habitat-related variation in food abundance for ground-foraging birds. We surveyed ground-dwelling arthropods throughout the breeding season and in three forest harvest types (clearcut, selection, and shelterwood stands managed for spruce, fir and hemlock) at the Penobscot Experimental Forest (PEF), Bradley, Maine, USA. Pitfall trapping during 2003 and 2004 was used to measure seasonal and habitat-related variation in abundance of ground-dwelling arthropod food items for hermit thrushes. Arthropods were sorted into relevant taxonomic and size class categories based on the known diet of hermit thrushes. Habitat variables included forest management type, stand-level structure and composition of tree species, and microhabitat measures in a 1 m² area around the pitfall traps. We used redundancy analysis to find stand-level and microhabitat measures that best explained variation in arthropod abundance during 2004. The majority of arthropod captures comprised three groups: ants (Formicidae, 44%), ground beetles (Carabidae, 13%), and spiders (Araneae, 11%). There was significant temporal variation in captures for many taxa. Notably, there were as many as six times more Araneae in early compared to late season samples suggesting the importance of Araneae to ground-foraging birds. Carabidae were more abundant in selection versus either shelterwood or clearcut stands on one sample date. Conversely, Formicidae and Curculionidae were more abundant in shelterwood plots on one and three sampling dates, respectively. Overall, our data provided little evidence that forest management type impacts arthropod food abundance, in stands 5–20 years post-harvest. Abundance of Carabidae was positively correlated with the number of softwoods less than 5 cm DBH and the number of hardwoods greater than 10 cm DBH, while abundance of Formicidae and Homopterans was negatively associated with these same measures. Several taxa were negatively associated with percent of the 1 m² around the pitfall that was shaded, including Araneae, Carabidae, Formicidae, and Staphylinidae. These results suggest that less-shaded forest microhabitats are important areas of increased food abundance for ground-foraging birds, regardless of forest management type or tree composition. Consequently, forest managers seeking to maximize food abundance for ground-foraging birds in managed spruce-fir forests should consider retaining some large diameter hardwood trees and use management techniques that reduce forest floor shading.     

美国杂交杏李果园害虫与天敌群落种-多度关系分析

应用对数级数分布模型、对数正态分布模型、几何级数分布模型和分割线段模型对生防美国杏李园、化防美国杏李园、混防美国杏李园、自生普通杏树园、自生普通李树园的害虫和天敌物种相对多度分布格局对比研究结果表明,对数级数分布模型、对数正态分布模型能较好地描述害虫与天敌的多样性,而几何级数分布模型和分割线段模型则不适于该果园害虫与天敌的多样性的拟合.     

Empty forests: Large carnivore and prey abundance in Namdapha National Park, north-east India

Illegal hunting poses a dual threat to large carnivores through direct removal of individuals and by prey depletion. We conducted a camera-trapping survey in the Namdapha National Park, north-east India, conducted as part of a programme to evaluate carnivore and prey species abundance. Clouded leopard (Neofelis nebulosa) was the only large carnivore detected by camera-trapping. Indirect evidences indicated the presence of the wild dog (Cuon alpinus) and leopard (Panthera pardus), however, there was no evidence of tigers (Panthera tigris), suggesting their possible extinction from the lower elevation forests. Of the major ungulate prey species, sambar (Cervus unicolor) and wild pig (Sus scrofa) were the only large prey detected, while the Indian muntjac (Muntiacus muntjak) was the only small prey species detected. Relative abundances of all species were appreciably lower than estimates from other tropical forests in south-east Asia. We suspect that illegal hunting may be the cause for the low carnivore and prey species abundance. An ongoing community-based conservation programme presents an opportunity to reduce local people’s dependence on hunting by addressing their socio-economic needs and for using their skills and knowledge of the landscape for wildlife conservation. However, long-term wildlife monitoring is essential to assess the efficacy of the socio-economic interventions in bringing about wildlife recovery.