Man-made litter on the shores of the United Arab Emirates on the Arabian Gulf and the Gulf of Oman

Frequency of occurrence, composition, and distribution of litter accumulating on western and eastern beaches of the Arabian Gulf and the Gulf of Oman, UAE, were investigated. In this study 27000 m² of UAE beaches were examined and 22771 items noted. An estimated 13.5×10⁶ man-made items are stranded along 800 km of Arabian Gulf and Gulf of Oman shorelines. Plastic fragments constituted 27.1% of the total items encountered. A strong correlation was found between plastic fragments and plastic bottles. Fishing floats and nettings represented 16.9% of the total items examined. A highly significant correlation (r=0.89) existed between the number of polystyrene blocks used as fishing floats and ropes, and nettings washed ashore. The west coast on the Arabian Gulf exhibited a much higher level of pollution by man-made debris than the east coast on the Gulf of Oman. Potential sources are pointed out and comparisons with other regions of the world are discussed.     

Modelization of the mercury fluxes at the air-sea interface

Aqueous and atmospheric Hg° concentrations for remote marine areas such as the equatorial Pacific Ocean and for coastal seas such as the North Sea and the Scheldt Estuary are discussed. Biological processes seem to be at the origin of the supersaturated Hg° concentrations in the water. On the other hand, transfer velocities across the air-sea interface were calculated with a classical shear turbulence model and with a wave breaking model. With these data, Hg° fluxes from the sea to the atmosphere were calculated: in the Pacific Ocean they range from 0.43 to 6.5 μg g Hg.m^?2. yr^?1 at a wind speed of 2.8 m.s^?1 and from 10.3 to 156 μg Hg.m^?2 yr^?1 at a wind speed of 54 m.s^?1, but they are still higher when wave breaking is considered (from 11 to 168 μg Hg.m^?2.yr^?1). These transfer fluxes are an order of magnitude higher in the Scheldt Estuary.     

Long-term trends in lobster populations in a partially protected vs. no-take Marine Park

Increasing the level of protection afforded to the marine environment requires assessment of the efficacy of existing marine protected areas (MPAs) in protecting exploited species. Long-term data from before and after the establishment of MPAs provide a rare but valuable opportunity to assess these effects. In this study we present long-term data (1977-2005) from before and after park establishment, on the abundance of spiny lobster Jasus edwardsii from fixed sites in a no-take marine park and a recreationally fished marine park, to assess the efficacy of no-take vs. partial protection. Lobster densities were comparable between both marine parks prior to park establishment, but the response of lobster populations differed markedly following protection. On average, legal-sized lobster were eleven times more abundant and biomass 25 times higher in the no-take marine park following park establishment, while in the partially protected marine park there has been no significant change in lobster numbers. Furthermore, no difference was found in densities of legal-sized lobster between the partially protected marine park and nearby fully-fished sites (<1 per 500 m²). Long-term data from fully fished and partially protected sites suggest long-term declines in lobster populations and reflect regional patterns in catch per unit effort estimates for the fishery. The long-term patterns presented provide an unequivocal example of the recovery of lobster populations in no-take MPAs, but clearly demonstrate that allowing recreational fishing in MPAs has little benefit to populations of exploited species such as J. edwardsii.     

Seasonal variations in the abundance of virus-like particles and bacteria in the floodwater of a Japanese paddy field

Abstract

Viruses are the most abundant biological entities in marine and freshwater environments. Many studies have shown the ecological importance of viruses in the primary production and microbial food web in aquatic environments. However, no studies have examined viral abundance in the floodwater of paddy fields. The present study surveyed the abundance of virus-like particles (VLPs) and bacteria in the floodwater of a Japanese paddy field under a long-term fertilizer trial since 1925 during the rice cultivation period. Virus-like particles and bacterial abundances in the floodwater ranged from 5.6 × 10⁶ to 1.2 × 10⁹ VLPs mL^?1 and from 9.2 × 10⁵ to 4.3 × 10⁸ cells mL^?1 with mean abundances of 1.5 × 10⁸ VLPs mL^?1 and 5.1 × 10⁷ cells mL^?1, respectively, and increased with an increase in the turbidity of the floodwater with suspended particles. The magnitude of seasonal variation was more than 50-fold for VLP abundance and 100-fold for bacterial abundance. The virus-to-bacterium ratios fluctuated over the rice cultivation period, ranging from 0.11 to 72 and their increase correlated with the decrease in bacterial abundance. Our results suggest that viral abundance in the floodwater of paddy fields is larger than in natural marine and freshwater environments.     

Impact of earthworms on the diversity of microarthropods in a vertisol (Martinique)

In a study of a 15-year-old pasture in Martinique (French West Indies), abundance and organization of microarthropod communities were correlated with the spatial distribution of the earthworm Polypheretima elongata (Megascolecidae). In patches of high earthworm density (133 individuals m^–2), microarthropod density was significantly higher (80000 individuals m^–2) than in patches with few earthworms (31 worms m^–2 and 49000 microarthropods m^{– 2}). The diversity of microarthropod communities followed a similar pattern, the Shannon index for Collembola communities being, respectively, 3.12 and 1.82 in and outside earthworm patches. These results suggest that mesofauna abundance and diversity might be at least partly determined by the activity of larger invertebrates, as a result of the dramatic effects that the latter group exerts upon soil structure, pore distribution and food resources. Received: 7 February 1997     

A survey of the forest site characteristics in a transect through the central Canadian boreal forest

As a contribution to the BOReal Ecosystem Atmosphere Study (BOREAS), a total of 97 sites have been surveyed in the boreal forest regions of Manitoba and Saskatchewan. The sites extend across an ecoclimatic transect through the boreal forest of central Canada, from aspen parkland to sub-arctic woodland. Sites were selected using satellite, air photograph, and forest cover map data. Each site represents a minimum 100 m by 100 m homogeneous stand, suitable for satellite imaging. Data collected at each site covers overstory (species composition, DBH, pathogens, age, etc.), understory (percent cover by species), debris, and soil characteristics. These data provide a background database for the diverse measurements of terrestrial ecology, land surface climatology, tropospheric chemistry, and remote sensing. Such data provide an important baseline for ongoing studies of the boreal forest in a region sensitive to global change. The results of this study aid integration of a variety of more detailed studies being carried out in the region and also allow comparison with other international studies of a similar nature. Sites are concentrated in two regions: north of Prince Albert, Saskatchewan, and west of Thompson, Manitoba. Additional sites are located in the area of the Boreal Forest Transect Case Study (BFTCS) between Batoche, Saskatchewan and Gillam, Manitoba. The surveyed sites were classified according to three criteria: dominant species (Picea mariana, Populus tremuloides, Pinus banksiana, or “mixed”), age (mature, immature, or young/recently disturbed), and productivity (low, medium, or high). Overstory and understory measurements were usually taken at three points within each site. Debris measurements were taken at two points, and soil measurements at one point per site. This paper focuses on overstory and debris data taken at 97 sites in 1993 and 1994. The sites are predominantly in medium and high productivity stands. Overstoiy. data, primarily from point-sampling, have been used to estimate stand basal areas, stem densities, volumes, and aboveground biomass (excluding foliage). Stand basal areas ranged from 5 m² ha^?1 to over 60 m² ha^?1. Stem densities ranged from a few hundred to over 40 000 stem ha^?1. Estimates of total aboveground biomass range from a few Mg ha^?1 to over 250 Mg ha^?1. The Prince Albert sites tend to have greater values than Thompson for basal area, volume and biomass, but stem densities are highly variable. Detritus data show values from zero to 60 Mg ha^?1. Generally, these values are small compared to aboveground biomass, but in recently disturbed sites the detrital mass can exceed aboveground biomass.     

SOIL CO2 FLUX IN GRASSLAND,AFFORESTED LAND AND RECLAIMED COALMINE OVERBURDEN DUMPS: A CASE STUDY

The aim of this study was to measure the in situ soil CO₂ flux from grassland, afforested land and reclaimed coalmine overburden dumps by using the automated soil CO₂ flux system (LICOR‐8100® infrared gas analyzer, LICOR Inc., Lincoln, NE). The highest soil CO₂ flux was observed in natural grassland (11·16 µmol CO₂ m⁻²s⁻¹), whereas the flux was reduced by 38 and 59 per cent in mowed site and at 15‐cm depth, respectively. The flux from afforested area was found 5·70 µmol CO₂ m⁻²s⁻¹, which is 50 per cent lower than natural grassland. In the reclaimed coalmine overburden dumps, the average flux under tree plantation was found to be lowest in winter and summer (0·89–1·12 µmol CO₂ m⁻²s⁻¹) and highest during late monsoon (3–3·5 µmol CO₂ m⁻²s⁻¹). During late monsoon, the moisture content was found to be higher (6–7·5 per cent), which leads to higher microbial activity and decomposition. In the same area under grass cover, soil CO₂ flux was found to be higher (8·94 µmol CO₂ m⁻²s⁻¹) compared with tree plantation areas because of higher root respiration and microbial activity. The rate of CO₂ flux was found to be determined predominantly by soil moisture and soil temperature. Our study indicates that the forest ecosystem plays a crucial role in combating global warming than grassland; however, to reduce CO₂ flux from grassland, mowing is necessary. Copyright © 2012 John Wiley & Sons, Ltd.     

Woodland structure,destruction and conservation in the Copperbelt area of Zambia

Between 1937 and 1983 a total of 391 400 ha of woodland, representing 51% of the 768 900 ha in the Zambia Copperbelt, had been deforested for industrial and household woodfuel. This has occurred in spite of a forest reservation programme that increased the area in forest reserves from 31 707 ha in 1942 to 252 715 ha in 1965. Between 1965 and 1980 the reserved forests were reduced to 246 930 ha and since then the area has remained static. The rapidly growing demand for charcoal by the increasing urban population, and the growing problem of acid dust and rain pollution from copper smelters, pose serious threats to forest conservation in this industrial region of Zambia. Current forest conservation is restricted to the establishment of exotic forest plantations and recently deforested areas are left to regenerate naturally.Forest destruction and conservation in the Copperbelt area were studied and the structure of old-growth and coppice woodland stands at 9 and 14 sites, respectively, investigated during 1982–1984. The Copperbelt vegetation is dominated by Brachystegia-Julbernardia woodland. Mean species diversity of 24·40·1 ha⁻¹ in coppice stands was higher than that of 18·9 found in old-growth stands. Stem density in coppice was 3·3 times that observed in old-growth woodlands. The majority of species (over 50%) in both old-growth and coppice were represented by less than 11 stems per sampling plot. Mean basal area at breast height in coppice aged 19–23 years was 14·33 m², which was 95% of the mean basal area of 15·15 m² found in old-growth woodlands.     

Pollution sources and spreading of sulphur dioxide in the North-Eastern Estonia

The greatest sources of atmospheric emissions of SO₂ in Estonia are caused by power plants (TP) which use oil shale. Since 1990 the amount of SO ₂ discharges has continuously decreased due to fall in production of electric energy, and it was from TP as follows: in 1990–1991 about 180–200 thousand tons, in 1992 about 140 and in 1993–1994 about 100 thousand tons. In 1990 the annual mean emission intensity of SO ₂ from all North-East (NE) Estonian pollution sources was fixed to be about 6.kg/s, with a maximum of 9.5–11 kg/s in winter period. In 1992–1993 the corresponding values were 3.5–4.6 and 5.1–6.8 kg/s. The single maximum concentrations (MC, per 30 min.) of SO ₂ in the overground air layer would be in the ranges 25–450 μg/m ³ depending on emission intensity and wind parameters. The annual mean concentrations are below 25 μg/m ³ on the main territory, but may be up to 50–75 μg/m ³ near the power plants. In Kohtla-Järve town the annual mean values of 15.8–19.1 μg/m ³ and MC values of 271–442 μg/m ³ were fixed during 1991–1994 by automatic air monitoring system. Many arable lands, forest areas and wild-life preserves are subjected to relatively high sulphur precipitation loads, exceeding 0.5 g S/m² per year, of which the role of emissions from local sources is about 60–95%. On the basis of air pollution concentration maps, the landscape of NE Estonia is classified into zones of high, moderate and low pollution level.     

Effect of industrial emissions on membrane permeability of epiphytic lichens in Northern Finland and the Kola Peninsula industrial areas

The impact of air pollution on membrane permeability of the epiphytic lichens Hypogymnia physodes and Bryoria fuscescens was studied in northern Finland and the Kola Peninsula to assess the effects of the Kola industrial emissions. The conductivity and quantity of K⁺ in leachates of the lichens were determined both as absolute and relative leakage. The K⁺ leakage from the lichens was the most sensitive indicator of membrane disturbance. Positive relationships between K⁺ leakage and decreasing distance from pollution sources and modelled atmospheric SO₂ concentrations were found and the K⁺ leakage and Cu and Ni concentrations of Scots pine bark were also highly correlated. The relative conductivity of leachates was inversely related to distance from sources, while the absolute conductivity of leachates from lichens was positively correlated with bark S. The ion leakage was higher in fruticose Bryoria fuscescens than in foliose Hypogymnia physodes, but the overall response to pollution was similar in both species. The methods used were able to identify areas of disturbed membrane function around the Kola industrial areas and local point sources in northern Finland. However, the majority of the studied sites in Finnish Lapland can be regarded as undisturbed background areas with respect to these sensitive lichens.     

放养条件下密度和补饲量对蛋鸡生产性能及蛋黄胆固醇含量的影响

选择45周龄体重接近的健康本地鸡441只,随机分为7组,在山西省太谷县生态养鸡场进行2(补饲量)×3(密度)两因子放养试验,研究林下种植苜蓿不同放养密度与补饲量对蛋鸡生产性能和蛋黄胆固醇含量的影响。补饲量设自由采食量50%、70%两个处理,密度为每667m2 100只、250只、400只3个处理,以笼养全程自由采食为对照,每组3个重复,每重复3个小区用于轮牧,小区面积为62 m2;预试期7 d,正试期70 d。结果表明:补饲量和放养密度互作对平均产蛋率影响极显著(P0.01),对蛋重和料蛋比影响不显著(P0.05)。笼养+自由采食组(CK)与补饲量70%、100只·667m-2组蛋重、平均产蛋率及料蛋比差异不显著(P0.05),但产蛋率显著高于其他各组(P0.05),蛋重显著高于补饲量50%、100只·667m-2组(P0.05),料蛋比显著低于补饲量50%组(P0.05)。补饲量和放养密度互作对蛋黄重、蛋黄胆固醇含量和全蛋胆固醇含量影响不显著(P0.05);放养密度对全蛋胆固醇含量影响极显著(P0.01)。笼养+自由采食组蛋黄重极显著高于补饲量50%、100只·667m-2组(P0.01),蛋黄胆固醇含量和全蛋胆固醇含量显著高于100只·667m-2组(P0.05)。补饲量70%下,100只·667m-2放养密度对牧草的破坏性小于其他放养密度。结合产蛋性能、蛋黄胆固醇含量以及草地保护,以70%补饲量+100只·667m-2组养殖模式较好,效果较佳。     

Influence of paclobutrazol on photosynthesis rate and dry matter partitioning in the apple tree

Four‐year‐old ‘Aki Fuji’ apple trees in their second leaf of fruiting were used to study the influence of paclobutrazol on photosynthesis rate (Pn) and the partitioning of dry matter in the different parts of the tree. It was found that the Pn of paclobutrazol‐treated trees was significantly higher than the untreated check trees. This is partially accounted for by the higher light intensity in the canopy of the paclobutrazol‐treated trees. Production efficiency of the paclobutrazol‐treated trees was 2.6 times higher than that of the untreated check trees. Paclobutrazol significantly changed the partitioning pattern of dry matter in the different parts of the tree. A much higher percentage of total dry matter was distributed to the fruit. However, a higher percentage of dry matter was found in the root of the paclobutrazol‐treated trees than in the untreated trees, the difference being mainly in the lateral and fibrous roots. Total dry matter accumulated per m² of occupied land of the paclobutrazol‐treated tree was 4% greater than that of the untreated check trees, whereas total dry matter accumulated per kg of leaves was essentially the same in both trees. Whether calculated on the basis of per m² of occupied land or per kg of leaves, the dry matter distributed into the fruit and into the root was considerably greater in the paclobutrazol‐treated trees than the untreated trees.     

黄淮地区稻茬小麦超高产群体特征研究

为探讨黄淮地区稻茬小麦超高产(9 000 kg·hm-2)群体的生长发育特性,以该区域推广面积较大的半冬性小麦品种‘连麦6号’、‘济麦22’和‘烟农19’为材料,在试验总结出包括基本苗调控和氮肥运筹等一套适宜黄淮地区稻茬麦超高产栽培技术的基础上,建立稻茬小麦高产和超高产群体,对其系列生育、生理特性以及产量要素进行调查分析。结果表明,与高产小麦群体(产量为7 380~7 889 kg·hm-2)相比,超高产(9 000 kg·hm-2)小麦群体单位面积穗数差异不显著,但穗粒数和千粒重显著增加;超高产小麦抽穗前茎蘖数较高产群体少,但分蘖成穗率较高;超高产群体小麦的叶面积指数,生育前期较高产群体低,抽穗后则显著高于高产群体,两者干物质积累生育前期无明显差异;超高产小麦抽穗期、乳熟期与蜡熟期的根冠比、根系伤流量均显著高于高产群体;超高产小麦粒叶比、茎鞘物质运转率和收获指数均高于高产群体。因此,本文提出了黄淮地区稻茬小麦超高产(9 000 kg·hm-2)群体的产量结构与群体指标:单位面积穗数(700±20)×104·hm-2,每穗实粒数32,千粒重42 g,茎蘖成穗率45%;抽穗期叶面积指数6.5~7.0;成熟期总干重20 700 kg·hm-2,粒叶比14 mg·cm-2;抽穗期根冠比0.28,根系伤流量7.1 g·m-2·h-1;收获指数0.45。     

Assessment of soil losses on cultivated land by using the Cs technique in the Upper Yangtze River Basin of China

This paper presents the results of using the ¹³⁷Cs technique to assess soil erosion rates of both sloping cultivated land and flat terraces in the Upper Yangtze River Basin, China. The study was carried out on eighteen sloping cultivated fields and four flat terrace fields in eight counties and cities over the eastern part of the basin. The ¹³⁷Cs-reference inventory ranged from 620.5 to 2573.2 Bq/m². For the 18 sloping cultivated fields, the average ¹³⁷Cs inventory over a field ranged from 204.9 to 1847.7 Bq/m², which accounts for 15–77% of the local ¹³⁷Cs reference inventory, and the average water erosion rate ranged from 758 to 9854 t/km² per year, with erosion rates of <1000 t/km² per year in two fields; 1000–5000 t/km² per year in eight fields; and >5000 t/km² per year in eight fields. It is apparent that most of the sloping cultivated fields suffer severe or very severe soil erosion. For the four terrace fields under this study, the average ¹³⁷Cs inventory over a field ranged between 915.8 and 2675.4 Bq/m², which accounts for 97–104% of the local ¹³⁷Cs reference inventory. However, water erosion is very slight on the terrace fields and little soil is lost from the terraces. The study also indicated that the severity of soil erosion is strongly related to soil texture and slope gradient.     

Assessment of heavy metal pollution in surface sediments of the Montenegrin coast: a 10-year review

Purpose

Heavy metals are among the most common environmental pollutants, which can be introduced into coastal areas from natural and anthropogenic sources, and thereby possibly impact marine organisms and human population. Therefore, the aim of this study was to evaluate the pollution level of Montenegrin coastal sediments by determining the concentrations of 10 metals and metalloids (Fe, Mn, Zn, Cu, Ni, Pb, Cr, Cd, As, and Hg) during one whole decade.

Materials and methods

Sediment samples were collected from 11 sites along the Montenegrin coast during the 2005–2016 exposure to different levels and sources of anthropogenic impact. The extent of pollution was estimated by determining total element concentrations in the sediment. Mineralized samples were analyzed for Cu, Ni, Fe, Mn, Cr, As, Pb, Zn, Cd, and Hg. Pollution status was evaluated using the contamination factor, pollution load index, and geo-accumulation index, as well as statistical methods, such as Pearson correlation coefficient (r) and cluster analysis (CA).

Results and discussion

This study showed that concentrations of individual metals at some locations were extremely high. The metal concentrations (in mg kg^?1) ranged as follows: Fe 1995–45,498; Mn 135–1139; Zn 10–1596; Cu 3.8–2719; Ni 2.94–267; Pb 0.1–755; Cr 2.5–369; Cd 0.1–5.4; As 0.1–39.1; and Hg 0.01–14.2. The calculated concentration factor and pollution load index indicates enrichment by either natural processes or anthropogenic influences. The geo-accumulation index value (Igeo) showed that one location was strongly or extremely polluted (3.78?<?Igeo ≤?6.15) with Hg in all investigated years, while extreme Igeo values for four bioactive elements, Pb, Cd, Cu, and Zn, were found in only a few single samples.

Conclusions

On the basis of the obtained values, it can be concluded that generally higher metal contents were distributed in Boka Kotorska Bay sites, although some extreme values were also recorded at the locations outside of the Bay. Geo-accumulation index and pollution load index showed that the metal levels were high enough to pose risk to the ecosystem.

     

The impact of marine reserves on nekton diversity and community composition in subtropical eastern Australia

The effectiveness of marine reserve protection on the biodiversity of aquatic assemblages (i.e. nekton) in subtropical eastern Australia was examined within two small (<6 km²) marine reserves and four non-reserve areas. The two marine reserves, and their corresponding non-reserves, were located in different geographical locations within Moreton Bay (north and south) and sites were surveyed with multiple hauls of a seine net. Species richness, evenness, density and mean size of the inshore communities were compared between the reserves and non-reserves. No statistical significant difference was detected in species richness between the areas however species evenness was significantly lower in the only non-reserve site impacted by commercial net fishing. Mean size of nekton was found to be significantly greater in the marine reserves compared to non-reserves but no statistical significant difference was found in the density of nekton between the study sites. Multivariate analysis revealed differences in community composition, particularly between the geographical locations where areas were impacted by different types of fishing pressure (recreational v commercial). These results highlight the impact commercial fishing can have on entire nekton assemblages, not just on targeted species. Our study demonstrates that the small marine reserves in Moreton Bay are protecting marine biodiversity and are thus at least partially achieving their management objective (to enhance the zone’s marine biodiversity).     

蓟运河故道消落带盐碱地土壤种子库特征

通过对蓟运河故道消落带的土壤种子进行萌发实验,确定了土壤种子库的物种组成、物种多样性指数和相似性指数,并对土壤种了库的物种特征进行了空间层次分析.结果表明:(1)蓟运河故道消落带土壤种子库共有16种植物,隶属于8科15属,其中藜科4种,菊科5种.3个区域土壤种子库物种相对多度和密度大小分布顺序为:洪淹区＞偶淹区＞常淹区.(2)不同区域种子库的Shannon—Wiener指数和Margalef丰富度指数随着水位的降低呈下降趋势,而生态优势度和Pielou均匀度指数有增大趋势.(3)种子库的空间分布特征明显,其中0--5 cm层种子数量最多,为623粒/m2;同时3个区域种子数量差异显著,洪淹区土壤种子库物种数量比偶淹区和常淹区分别多出253和353粒/,n2,而偶淹区土壤种子库物种数量与常淹区仅相差100粒/m2.     

Effect of different densities of parthenium weed (Parthenium hysterophorus L.) on the performance of direct-seeded rice under aerobic conditions

Parthenium weed (Parthenium hysterophorus L.) is an emerging weed species in direct-seeded aerobic systems of rice production. This two-year field study was conducted to evaluate the effect of five different densities (0, 5, 10, 15 and 20 plants m^?2) of parthenium weed on rice yield and yield-related attributes. Parthenium weed produced ca. 38 to 178% higher biomass at its densities of 10 to 20 plants m^?2 as compared to the lowest density of 5 plants m^?2. The paddy yield and yield-related attributes were negatively affected with an increase in the parthenium weed density. In both years, the highest reductions in number of rice panicles (14 to 17%), panicle length (10 to 11%), number of grains per panicle (11 to 18%), 1000-grain weight (8 to 21%) and paddy yield (30 to 35%) were recorded at the highest parthenium weed density (20 plants m^?2) tested. However, the lower densities of 5 to 15 parthenium weed plants m^?2 also caused 11 to 24% and 12 to 26% losses in paddy yield during the years 2016 and 2017, respectively. Therefore, this weed species should be controlled below the density of 5 plants m^?2 to avoid the substantial yield losses (over 15%) in direct-seeded rice.     

Annual population dynamics and production ecology of Testacea (Protozoa,Rhizopoda) in an aspen woodland soil

The population studies of Testacea in an aspen woodland soil revealed 28 taxa of living Testacea, 14 of which were considered constant. The 14 species, while comprising 98 and 96% of the mean annual density and total annual production numbers respectively, accounted for only 80% of the mean annual biomass and 86% of the total annual production biomass. All 14 species had a peak in abundance in autumn, immediately or soon after leaf litter fall. While most species maintained small, active and reproducing populations over the winter period, some maintained higher than normal densities, had seasonal peaks in abundance and biomass, or higher than normal rates of production and turnover. All species had an increase in reproduction and usually in abundance also during the late winter-early spring period before spring thaw. The annual mean weekly density and biomass and the annual production totals tor numbers and biomass were highest in the H layer and lowest in the L. The F layer produced the highest numbers of generations per year and the highest annual mean weekly biomass turnover rate for most of the species. The majority of the periods of high intrinsic rate of natural increase, biomass production and turnover occurred during or after an increase, a decrease or a stabilization in soil moisture content. Mean annual biomass and total annual production were estimated as 0.72 and 206 g wet weight m^?2 respectively. The aspen woodland soil Testacea (in a mor humus) had a much higher production and number of generations per year than Testacea from mull and moder humus forms.Total annual ingestion, respiration losses and egestion losses for testate amoebae in an aspen woodland soil were calculated as 1377, 344 and 826 g wet weight of biomass m^?2, respectively. The annual secondary production of Testacea was about 250–300 times the standing crop of Testacea in all the soil layers. The dry weight of carbon respired per year by the Testacea was estimated as 16.2 g m^?2, which amounted to about 6% of the total carbon input.     

Spatial distribution of isopods in an oak–beech forest

Soil macroinvertebrates were studied in a Mediterranean-type forest on brown-pebble forest soils in southern Russia. At the site, 144 intact soil cores (76 cm² each) forming a grid of 24 × 6 units were taken in order to determine animal spatial distribution. Abundance of isopods was 166.3 ± 16.0 indiv. m^–2 and they constituted about 12% of the total macrofaunal abundance. Biomass of isopods was 3.5 g m^–2, or about 21% of the total biomass of macrofauna. Three woodlice genera (Armadillidium, Cylisticus, and Trachelipus) were found at the site. The two latter genera formed almost all (93%) of the isopod population. We found that spatial distribution of woodlice was heterogeneous: areas with 4–5 individuals per sample were neighboring those without animals. In order to study soil factors influencing isopod distribution in the brown-pebble forest soil, the size of a sample was artificially increased by combining adjacent sample units. Litter mass (r = 0.41) and loss on ignition (LOI) (r = –0.55) significantly influenced isopod distribution. Soil pH was near neutral (6.79), LOI was 8.39, and the water holding capacity was 70.9%. Pebbles comprised up to 84% of the sample's mass. Ca. 40 samples are recommended for estimation of isopod abundance in brown forest soil.