The distribution of soil macrofauna on the west ridge of Gunung (Mount) Mulu,Sarawak

Summary The macrofauna of the soils on the west ridge of Gunung Mulu in 4th Division, Sarawak, were sampled during February and March 1978. The eleven sampling sites ranged from near the base of the mountain at 130 m a.s.1. to the summit at 2.376 m.Altitudinal changes from lowland rain forest (mixed dipterocarp forest) to lower montane and upper montane rain forests are concomitant with changes in soil from red yellow podzolics and regosols to peaty gley podzolics and organic peats.The abundance of the total macrofauna declined from 2,579 individuals m^-2 at 130 m to 145 m^-2 at 2,376 m. Declining population densities of ants and termites correlated significantly with increasing altitude but the effect on other groups was variable. Changes in total biomass were erratic and varied from 4.1–6.2 g m^-2 (alc. w.w.) in the dipterocarp forest soils to 5.8 g m^-2 in the lower montane, 9.3–20.2 g m^-2 in the upper montane (tall facies) and 1.9–9.5 g m^-2 in the upper montane (short and summit facies). Only the decline in the biomass of termites and ants correlated significantly with altitude. Other groups remained fairly constant, varied erratically or increased in the middle altitudes.The dipterocarp forest soil macrofaunal biomass was dominated by termites, beetles and earthworms (Megascolecidae and Moniligastridae), with ants the dominant predators. The lower montane forest was a transitional and ill-defined zone on the mountain and the soil macrofauna was also transitional to some extent. Termite biomass fell substantially and earthworms replaced them as the dominant detritivores, with beetles in a secondary role. Formicidae remained as the major predators. With the inception of peats in the upper montane forest (tall facies), the macrofauna was dominated by Coleoptera with earthworms, Diptera larvae and Blattodea in lesser roles. With increasing exposure in the upper montane forests (short and summit facies), several major groups disappeared altogether. The soils were dominated by Blattodea with Coleoptera and Megascolecidae of lesser importance. Chilopoda and Arachnida replaced Formicidae as the dominant predators.     

Foliage litter turnover and earthworm populations in three beech forests of contrasting soil and vegetation types

Summary Leaf litter decomposition, levels of accumulated litter as well as the abundance and biomass of earthworms were measured in three mature beech forests in southern Sweden: one mor site, one poor mull site, and one rich mull site. The disappearance rate of beech litter, measured with litter bags, increased with increasing soil fertility. On the rich mull site, the disappearance rate was much higher than in the two other forests, due to the combined effects of higher earthworm activity, more favouable soil moisture conditions, and higher litter quality. Incubating the litter in finely meshed bags (1-mm mesh) to exclude macrofauna had a great effect on litter mass loss in the rich mull site, but it had only a minor effect in the other sites. Simultaneous incubations of local and transplanted leaf litter on the three study sites showed that the substrate quality of the litter increased in the order: mor site — poor mull site — rich mull site. Lignin, N, and P concentrations of the leaf litter failed to explain the observed differences in decomposition rates, and acid/base properties are suggested to be more important. Earthworm numbers per m² were 2.5 (1 species) in the mor, 40 (6 species) in the poor mull and 220 (9 species) in the rich mull forest. Soil chemical conditions, notably pH, were suggested as the main factors determining the inter-site differences in abundance and species composition of earthworms. The role of litter decomposition and earthworm activity in the accumulation of organic matter in the forest floor in different types of beech woodlands are discussed.     

Soil macro-invertebrates and litter disappearance in a Japanese mixed deciduous forest and comparison with European deciduous forests and tropical rainforests

Soil macro-invertebrates and rate of litter disappearance were studied in a ridge plot with moder (mor) humus and a bottom plot with mull humus on a slope in a temperate mixed deciduous forest in Kyoto, Japan (J). The results were compared with those from two German beech forests (G) representative of European deciduous forest mor and mull. Between-plot differences in biomass of total saprophagous animals was much smaller in J than in G, which is dominated by earthworms. Susceptibility to soil acidity and zoogeographical distribution of earthworms were suggested to be related to this situation. Biomass of soil macro-invertebrates and litter turnover rate were compared among J, G and three types of tropical rainforests in Malaysia (M) in relation to climatic conditions. Taking into account among-site differences in temperature and moisture, which affect microbial activity and in biomass of saprophagous macro-invertebrates especially earthworms, the following order of importance of soil macro-invertebrates in determining the rate of litter disappearance was suggested: G>J>M. Based on the comparison of biomass of earthworms among European deciduous forests, Japanese deciduous forests and tropical rainforests, as well as on the presence or absence of anecic earthworms in these forests, it was suggested that this ranking could be generalized to European deciduous forests > Japanese deciduous forests > tropical rainforests. It was pointed out that this order was the opposite of the gradient in evapotranspiration rate existing among these regions.     

Enchytraeid numbers,biomass and respiratory metabolism in a beech woodland - Wytham Woods,Oxford

Summary The mean annual population density of enchytraeids in the litter and upper 6 cm of soil was found to be 14,590 m^-2. Mean individual weights approximated 116, 158 and 151 g wet wt. in the litter, 0–3 cm and 3–6 cm strata respectively. The mean biomass was estimated to be 1.908 g wet wt m^-2. Vertical migration was shown to occur, the upward migration in late Autumn was a response to temperatures in the litter being temporarily higher than those of the 0–3 cm stratum. As a result of upward vertical migration and possibly recruitment, numbers reached a maximum in the litter during Winter. On an annual basis the litter, 0–3 and 3–6 cm strata contained 41.43, 46.44 and 12.12% respectively of the extracted enchytraeids. The equivalent biomass values were 33.18, 52.46 and 14.36%. Total numbers and biomass revealed a general picture of high values in late Autumn to Winter which gradually decreased through Spring and Summer except for a minor peak in May–June. The annual oxygen consumption of the enchytraeids approximated 4.285 l O₂ m^-2 yr^-1 (20.461 kcal85.610 kJ) and accounted for 1.63% of the total soil metabolism. A production/biomass (P/B) ratio of 4.93 was estimated as was a net population efficiency of 32%. For this site the contribution by enchytraeids to total soil respiration is about one-third that of the earthworms and an order of magnitude greater than that of the nematodes.     

Earthworm Succession in Afforested Colliery Spoil Heaps in the Sokolov Region, Czech Republic

Earthworm communities were studied at six heap sites representing a chronosequence of Alnus glutinosa (black alder) stands (age 3–62 years) and compared with those on an unameliorated heap and in an alder stand (60 years old) on natural soil. Spoil heaps in the open‐cast coal mining area near Sokolov (northwestern Bohemia) were mainly reclaimed using afforestation. No earthworms were found on the virgin heap. Young plots were colonized by euryecious epigeic earthworms (i.e., those living above soil surface), but higher proportions of endogeic species (i.e., soil dwellers), did not appear until after more than 30 years of succession. The density and biomass of earthworms increased from the youngest stand (67 individuals/m²; 5 g/m²) to the older ones (e.g., 407 ind/m²; 13 g/m² in the 23‐year‐old stand). However, both parameters were low in the oldest stand (35 ind/m²; 3 g/m²), but this may have been the result of extensive soil disturbance. Earthworm populations were often higher in reclaimed sites than in the control alder stand (150 ind/m²; 7 g/m²). However, the community structures were different, with the control being dominated by the litter‐feeding species, Dendrobaena vejdovskyi.     

Earthworm Invasion,Fine-root Distributions,and Soil Respiration in North Temperate Forests

The efflux of carbon from soils is a critical link between terrestrial ecosystems and the atmosphere. Current concerns about rising atmospheric carbon dioxide (CO₂) concentrations highlight the need to better understand the dynamics of total soil respiration (TSR, sum of root and heterotroph respiration) in changing environments. We investigated the effects of exotic earthworm invasion on TSR, fine-root distributions, and aboveground litterfall flux in two sugar maple-dominated forests in two locations in New York State, USA. The Arnot Forest in central New York was harvested in the late 19th century and has no history of cultivation. Tompkins Farm in eastern New York regenerated following abandonment from cultivation approximately 75 years ago. Arnot had 20% higher total soil CO₂ efflux (880 g C m^–2year^–1) than Tompkins (715 g C m^–2year^–1). The presence of earthworms had no influence on TSR at either location. However, fine-root (< 1 mm diameter) biomass in earthworm plots (350 g/m²) was significantly lower than in worm-free reference plots (440 g/m²) at Arnot. Fine-root nitrogen (N) concentrations were not influenced by earthworms, and total fine-root N content was significantly reduced in the presence of earthworms at Arnot. Our results indicate that the presence of exotic earthworms is not presently affecting net C emission from soil in these forests. They also suggest a change in root function in earthworm plots that is not associated with higher fine-root N concentration, but that increases efficiency of nutrient uptake and also may enhance the belowground supply of C for heterotroph metabolism.     

Ecological and site historical aspects of N dynamics and current N status in temperate forests

Ecological developments during Holocene age and high atmospheric depositions since industrialization have changed the N dynamics of temperate forest ecosystems. A number of different parameters are used to indicate whether the forests are N‐saturated or not, most common among them is the occurrence of nitrates in the seepage water below the rooting zone. The use of different definitions to describe N saturation implies that the N status of ecosystems is not always appropriately assessed. Data on N dynamics from 53 different German forests were used to classify various development states of forest ecosystems according to the forest ecosystem theory proposed by Ulrich for which N balances of input – (output plus plant N increment) were used. Those systems where N output equals N input minus plant N increment are described as (quasi‐) Steady State Type. Those forests where N output does not equal N input minus plant N increment as in a ‘transient state.’ Forests of the transient state may lose nitrogen from the soil (Degradation Type) or gain nitrogen [e.g., from atmospheric depositions (Accumulation Type)]. Forest ecosystems may occur in four different N states: (a) (quasi‐) Steady State Type with mull type humus, (b) Degradation Type with mull type humus, (c) Accumulation Type with moder type humus, and (d) (quasi‐) Steady State Type with moder type humus. Forests with the (quasi‐) steady state with mull type humus in the forest floor (n= 8) have high‐soil pH values, high N retention by plant increment, high N contents in the mineral soils, and have not undergone large changes in the N status. Forests of the Degradation Type lose nitrogen from the mineral soil (currently degradation is occurring on one site). Most forests that have moder or mor type humus and low‐soil pH values, and low N contents in the mineral soil have gone through the transient state of organic matter loss in the mineral soils. They accumulate organic matter in the forest floor (accumulation phase, currently 21 sites are accumulating 6–21 kg N ha^?1 yr^?1) or have reached a new (quasi‐) steady state with moder/mor type humus (n= 15). N retention in the accumulation phase has significantly increased in soil with N deposition (r²= 0.38), soil acidity (considering thickness of the forest floor as indices of soil acidity, r²= 0.43) and acid deposition (sulfate deposition, r²= 0.39). Retention of N (4–20 kg N ha^?1 yr^?1) by trees decreased and of soils increased with a decrease in the availability of base cations indicating the important role of trees for N retention in less acid soils and those of soils in more acid soils. Ecosystem theory could be successfully applied on the current data to understand the dynamics of N in temperate forest ecosystems.     

Soil CO<Subscript>2</Subscript> flux affected by <Emphasis Type="Italic">Aporrectodea caliginosa</Emphasis> earthworms

The effects of Aporrectodea caliginosa earthworms on both carbon dioxide (CO₂) accumulation in and emissions from soil, as well as the simultaneous impact of earthworms on soil microbiological properties were investigated in a microcosm experiment carried out over 5.5 months. Concentration of CO₂ in soil air was greater at a depth of 15 cm when compared with a depth of 5 cm, but varied during the season both in control and earthworm-inhabited chambers. Peaks of CO₂ concentrations at both depths occurred in both treatments during August, approximately 80 days after the experiment started. Generally, the presence of earthworms increased the CO₂ concentration at 15-cm depth. Larger CO₂ emissions were consistently recorded in conjunction with higher amounts of CO₂ in soil air when chambers were inhabited by earthworms. The total CO₂ emissions during the experimental period covering 161 days were estimated at 118 g CO₂-C m⁻² and 99 g CO₂-C m⁻² from chambers with and without earthworms respectively. Moreover, the presence of earthworms increased microbial biomass in the centre and at the bottom of chambers, and enhanced both dehydrogenase activity and nitrifying enzyme activity in the soils. We suggest that the effect of earthworms on both the enhanced soil accumulation of CO₂ as well as emissions of CO₂ was mostly indirect, due to the impacts of earthworms on soil microbial community.     

Soil microarthropods and macrofauna in monsoon tropical forests of Cat Tien and Bi Dup-Nui Ba National Parks,southern Vietnam

The abundance, biomass, vertical distribution, and taxonomic composition of soil invertebrates (springtails, macrofauna, and termites) were studied in forest formations differing in edaphic and climatic conditions: lowland forests dominated by Lagerstroemia spp. or Dipterocarpus spp. in the Cat Tien National Park and in a mountain pine (Pinus kesiya) forest on the Da Lat Plateau, southern Vietnam. In the lowland forests, springtails had a relatively low density (10000–12000 ind./m²), but their diversity was high (41–43 species in each forest). The density of large soil invertebrates (without ants and termites) reached 500–700 ind./m² at a biomass of approximately 30 g/m² (with earthworms accounting for up to 230 ind./m² and 19–28 g/m²). Among termites, species of the genera Macrotermes and Odontotermes were dominant. Their total biomass in some areas exceeded 15–20 g/m². In the mountain pine forest, the total biomass of soil macrofauna was approximately 11 g/m², the abundance and diversity of springtails were low (7500 ind./m², 28 species), and wood-destroying species of the genera Schedorhinotermes sp. and Coptotermes sp. dominated among termites.     

Effects of earthworms on biomass production,nitrogen allocation and nitrogen transfer in wheat-clover intercropping model systems

The effects of earthworms (Lumbricidae) on plant biomass production and N allocation in model intercropping systems of winter wheat and white clover were evaluated in two pot experiments. Wheat and wheat-clover mixtures were grown in a low-organic loam soil, earthworms were added at densities comparable to field population densities and the experiments were terminated 48 and 17 d after earthworm introductions. In both experiments, earthworms significantly increased the biomass and N uptake of wheat while they had generally no effects on clover. As a result, earthworm activity increased the proportion of wheat biomass in the total plant biomass of the mixture. Nitrogen budgets of the experiment lasting 48 d indicated that additional N in the system made available by earthworm activity was primarily taken up by the wheat. Earthworms also affected intra-plant N allocation in wheat which had significantly higher shoot:root N ratios when earthworms were present. When clover was labelled with ¹⁵N in the experiment which lasted 17 d, endogeic earthworms significantly reduced the amounts of ¹⁵N excess transferred from living or decomposing clover roots to accompanying wheat plants. Earthworms assimilated small quantities of ¹⁵N tracer from decomposing clover roots but not from living clover roots. The results of these model experiments suggest that earthworms can affect the balance between intercropped cereals and legumes by altering intra- and inter-plant N allocation. This revised version was published online in June 2006 with corrections to the Cover Date.     

Response of alpine meadow communities to burrow density changes of plateau pika (Ochotona curzoniae) in the Qinghai-Tibet Plateau

Plateau pika (Ochotona curzoniae) is a key component of alpine meadow ecosystem in the Qinghai- Tibetan Plateau, and the increase of its number leads plant components of alpine meadow ecosystem to adaptively response. A field survey was carried out to determine the response of alpine meadow community to population densities of plateau pika by using available burrow density to replace the population density of plateau pika. This study showed that the height of alpine meadow communities gradually increased, and the cover of alpine meadow communities firstly decreased, and then increased as the available burrow density increased. With the increase of available burrow density, the richness index of alpine meadow communities firstly decreased and then increased, and the evenness index of alpine meadow communities firstly increased and then decreased, however, the diversity index of alpine meadow communities firstly increased, and then decreased, finally increased. In the increasing process of available burrow density, the total plant biomass and the unpalatable plant biomass firstly decreased and then increased, and the palatable plant biomass firstly increased and then decreased, indicating that the palatable plant biomass was the highest and the unpalatable plant biomass was the lowest at 14 available burrow per 625 m². In the economic groups of plant biomass, the weed biomass was the highest and the legume biomass was the lowest at any available burrow densities, and the grass biomass and the sedge biomass were related to available burrow densities, indicating that the sedge biomass were bigger than the grass biomass at 3 available burrow per 625 m², inverse at 54 available burrow per 625 m², similar between 3 and 34 available burrow per 625 m². Accompanying by the increase of available burrow densities, the legume biomass and the sedge biomass significantly decreased (P < 0.05) and the legume became disappearance at 54 available burrow per 625 m²; the grass biomass firstly increased and then decreased, peaking at 14 available burrow per 625 m². The weed biomass firstly decreased and then increased, and was the lowest at 14 available burrow per 625 m². This study suggested that the responses of alpine meadow communities to population density of plateau pika at 14 available burrows per 625 m² were more sensitive than that at other available burrow per 625 m² from plant species diversity, biomass, height, cover and economic group.     

Earthworm Communities in the Pineapple (Ananus comosus) and Mixed Fruit Plantations of West Tripura, India

Present studies on the community characteristics of earthworms revealed the occurrence of 11 species of earthworms in the pineapple (Ananus comosus) and 14 species in the mixed fruit plantations of west Tripura (India). While 9 species of earthworms namely Drawida assamensis, Drawida papillifer papillifer, Drawida nepalensis, Kanchuria sp., Metaphire houlleti, Eutyphoeus gigas, Eutyphoeus scutarius, Eutyphoeus comillahnus and Pontoscolex corethrurus are of common occurrence to both the pineapple and the mixed fruit plantations, two and five earthworm species namely Kanchuria sumerianus, Eutyphoeus sp. and Metaphire posthuma, Perionyx excavatus, Lampito mauritii, Amynthus alexandri, Eutyphoeus gammiei are restricted to the pineapple and the mixed fruit plantations respectively. Earthworms were found mostly within 15 cm depth of soils having temperature 25–25.8 °C, moisture 18.8–22.4 %, water holding capacity 26–31.7 % and organic matter content 2.4–4.0 %. Mean earthworm densities (158 ind. m^?2) was significantly higher (p < 0.01, t = 9.67) and biomass (36.67 g m^?2) significantly lower (p < 0.01, t = ?5.98) in the pineapple plantation than the mixed fruit plantation (density 93 ind. m^?2, biomass 56 g m^?2). High density value of earthworms in pineapple plantation is linked with dominance of D. assamensis and high biomass value in mixed fruit plantation was due to the higher relative abundance of larger species like E. gigas, E. scutarius, E. comillahnus and E. gammiei. Compared to the mixed fruit plantation, significantly (p < 0.05) higher index of dominance, lower index of diversity, species richness index and species evenness were recorded in the pineapple plantation.     

Abundance and biomass estimates of the benthic fauna in Admiralty Bay,King George Island,South Shetland Islands

Summary Quantitative benthic samples were collected along three transects in Admiralty Bay, King George Island, South Shetlands. At each of a total of 18 stations, between 15 and 250 m depth, we took 3 replicate samples with a van Veen grab. Animals collected were classed into major groups. Abundance and biomass per m² was calculated for each sampling site. Considerable population densities and high biomass values were found. Most abundant groups were Bivalvia, Polychaeta and Amphipoda, whereas the largest part of the biomass was due to Ascidiacea, Ophiuroidea, Echinoidea, Polychaeta and Bivalvia. The maximum abundance recorded was 36,000 ind m^-2 while the average was approximately 6500 ind m^-2. Maximum biomass was over 2400 g m^-2 with an average of ca. 700 g m^-2. The contribution to the total biomass by groups such as the Oligochaeta, Cumacea and Tanaidacea was higher in the inner shallow part of Admiralty Bay (Ezcurra Inlet) than in the deeper areas of the bay. Our results confirm the reports on an unusually high density and biomass of the Antarctic sublittoral benthic fauna. Sessile suspension feeders belonging to the Bivalvia, Ascidiacea, sedentary Polychaeta, and vagile scavengers of the Ophiuroidea, Amphipoda and errant Polychaeta are the most significant groups in the Antarctic Ecosystem. The total benthic biomass in Admiralty Bay, based on the present preliminary quantitative data, was estimated to be over 600,000 t. This value is probably still an underestimate.     

黄河源园区高寒草地碳储量估算及其影响因素

高寒草地碳储量及其影响因素研究是认识青藏高原草地生态系统乃至陆地生态系统碳循环和气候变化的关键之一。利用2021年8月上旬地面调查数据与同期高分6号遥感数据建立回归关系,在反演研究区植被地上、地下生物量碳密度和0—40cm土壤层有机碳密度基础上,估算了黄河源园区高寒草地有机碳储量,并通过路径分析探讨了土壤理化性质对碳密度的影响驱动机制。结果表明：(1)2021年黄河源园区地上生物量、地下生物量、0—40cm土壤层碳密度分别为37.65g/m²、1305.28g/m²、4769.11g/m²;总碳储量为100.44Tg(1Tg=10¹²g),植被层和土壤层碳储量分别分为22.06Tg、78.38Tg,占总碳密度的21.96%、78.04%。(2)黄河源园区高寒草甸和高寒草原两种草地类型地上生物量碳密度分别为41.27g/m²、30.76g/m²;地下生物量碳密度分别为1661.41g/m²、618.74g/m²;0...     

Effects of soil density on yield and fertilizer requirement of sugar beet

Three experiments (1971–3) on medium-textured soils of low organic-matter content examined the effects of soil density on seedling emergence and yield of sugar beet, and the interactions between soil density and the requirement for nitrogen (N) and phosphate (P₂O₅) fertilizers. Three soil densities were produced by rolling and harrowing, dutch harrowing twice, and power harrowing once; each was tested with 75, 150 and 225 kg ha^-1 N and 0, 100 and 200 kg ha^-1 P₂O₅. Most seedlings emerged on the medium-density treatment produced by dutch harrowing twice. The crop in the least dense soil treatment, produced by power harrowing once, consistently yielded slightly more sugar than the medium-density treatment, which yielded significantly more than the most dense treatment. In dense soil, created by rolling and harrowing, there was a response to more fertilizer N than the less dense ones; the crop did not respond to phosphate fertilizer. Mechanical impedance, not toxic concentrations of ethylene in the soil atmosphere, appeared to be the cause of reduced yield on the dense soils; these reductions were considerable at dry soil bulk densities in excess of 1·5 g ml^-1.     

Production of Gammarus pulex L. (Amphipoda) in a small Danish stream

Quantitative samples of Gammarus pulex L. taken from a small Danish stream during 1975 showed mean annual population densities varying from 500 m^–2 in early May to 5 500 m^–2 in late September. The mean annual biomass was 1.5 g dry weight m^–2. No discrete cohorts could be distinguished from the size frequency distributions. Annual production, estimated by the size-frequency method, was 3.9 g dry weight M^-2 and P/B ratio was 2.6. The contribution to trout energetics may have been as much as 17%.     

The ecology of Lake Nakuru (Kenya)

Summary Consumer biomass and spatial distribution in the equatorial alkaline-saline Lake Nakuru were studied from 1972–1976. These data will provide the basis for estimating feeding and production rates and for quantifying energy flow at the consumer level. Two of the main consumers, the Lesser Flamingo (Phoeniconaias minor) and the Soda Tilapia (Sarotherodon alcalicus grahami), were covered by earlier papers. The biomass of the only planktonic crustacean, the copepod Lovenula (=Paradiaptomus) africana was very high (1.5 gDW (dry weight)·m^-3, mean in 1972/73) in comparison with other tropical lakes. Lovenula was absent in 1974 and 1975, and at very low levels (0.1–0.4 gDW·m^-3) in part of 1976. Among the rotifers Brachionus dimidiatus dominated in 1972/73 (0.2 gDW· m^-3), but was outnumbered by B. plicatilis throughout most of 1974 to 1976 (mean total rotifer biomass 1.4 gDW· m^-3, peak densities 7 gDW·m^-3); during high salinity periods (>20) Hexarthra jenkinae occurred in very low numbers. For short periods rotifers can be the dominant species of L. Nakuru. Aquatic heteroptera (four species) played a minor role: they contributed 0.4% to total consumer biomass in 1972/73; in 1974–1976 the lake had no aquatic heteroptera. Benthic biomass (0.4 gDW·m^-2) was within the range of other tropical lakes, it consisted almost exclusively of Leptochironomus deribae. Bird counts of the twelve most important species are given for the years 1972–1974: Pelecanus onocrotalus accounts for 90% of the biomass (0.44 gDW·m^-3, mean 1972/73) with peak densities of almost 20,000 birds.-The consumer organisms covered by this and the two preceding papers represent >99% of L. Nakuru's consumer biomass. Population dynamics of various consumer species are discussed.     

Stand fine root biomass and fine root morphology in old-growth beech forests as a function of precipitation and soil fertility

Only very limited information exists on the plasticity in size and structure of fine root systems, and fine root morphology of mature trees as a function of environmental variation. Six northwest German old-growth beech forests (Fagus sylvatica L.) differing in precipitation (520 – 1030 mm year^–1) and soil acidity/fertility (acidic infertile to basic fertile) were studied by soil coring for stand totals of fine root biomass (0–40 cm plus organic horizons), vertical and horizontal root distribution patterns, the fine root necromass/biomass ratio, and fine root morphology (root specific surface area, root tip frequency, and degree of mycorrhizal infection). Stand total of fine root biomass, and vertical and horizontal fine root distribution patterns were similar in beech stands on acidic infertile and basic fertile soils. In five of six stands, stand fine root biomass ranged between 320 and 470 g m^–2; fine root density showed an exponential decrease with soil depth in all profiles irrespective of soil type. An exceptionally small stand fine root biomass (<150 g m^–2) was found in the driest stand with 520 mm year^–1 of rainfall. In all stands, fine root morphological parameters changed markedly from the topsoil to the lower profile; differences in fine root morphology among the six stands, however, were remarkably small. Two parameters, the necromass/biomass ratio and fine root tip density (tips per soil volume), however, were both much higher in acidic than basic soils. We conclude that variation in soil acidity and fertility only weakly influences fine root system size and morphology of F. sylvatica, but affects root system structure and, probably, fine root mortality. It is hypothesized that high root tip densities in acidic infertile soils compensate for low nutrient supply rates, and large necromasses are a consequence of adverse soil chemical conditions. Data from a literature survey support the view that rainfall is another major environmental factor that influences the stand fine root biomass of F. sylvatica.     

Nest and soil populations of Trinervitermes spp. with particular reference to T. geminatus (Wasmann), (Isoptera), in Southern Guinea savanna near Mokwa,Nigeria

Summary Nest and soil populations of Trinervitermes spp. were estimated on grazed secondary savanna woodland near Mokwa cattle ranch and on primary savanna woodland, 6 km from the ranch. Nest populations were estimated by obtaining a relationship between size of nest and the number of termites in the nest and using the relationship to estimate populations in measured nests within the study area.Mound populations of T. geminatus, by far the most abundant species, were 222 m^-2 at a mound density of 232 ha^-1 at the ranch, and 225 m^-2 at a mound density of 175 ha^-1 on primary savanna woodland. The mound population at the ranch represented a fresh weight biomass of 1.089 g m^-2. Changes in abundance of the mound population of T. geminatus were correlated with breeding and foraging cycles. Maximum numbers (388 m^-2, 2.03 g m^-2) in August/September were reduced by the flight of alates and loss of foragers to predators; thereafter, the population continued to decrease (126 m^-2, 0.57 g m^-2) until the cessation of foraging in April/May and numbers of larvae and nymphs began to increase. Soil and mound sampling in primary and secondary savanna showed that although T. geminatus is a mound inhabiting species, two thirds of the mound plus soil population was outside the mounds giving a total population of 737 m^-2 (3.08 g m^-2). Alate production was estimated at 15.5 m^-2 (0.19 g m^-2) and neuter production at 367 m^-2 (1.66 g m^-2); production/biomass ratio was 1.0 T. togoensis (total population of 21 m^-2) and T. occidentalis (200 m^-2) had 90–96% of the total numbers outside the mounds, indicating that these two species were primarily subterranean.     

Numbers and biomass of centipedes (Lithobiomorpha: Chilopoda) in a Betula-Alnus woodland in N.E. England

Summary Over a period of 1 year the mean monthly population densities of L. forficatus varied between 7.58 m^-2 (February) and 24.07 m^-2 (October). The equivalent values for L. crassipes were 17.05 m^-2 (February) and 64.17 m^-2 (October). The annual mean population density of the two species was estimated at 51 m^-2 with a biomass of 0.585 g live wt m^-2. Less than 4% of the total lithobiid population was found in decaying logs and tree stumps, most of the population inhabited the soil/litter layers.Seasonal fluctuation in numbers was shown to be unimodal in L. forficatus and bimodal in L. crassipes. A similar pattern was noted in the status of the ovaries, L. forficatus appears to have a single peak breeding period (September) while L. crassipes has two (June and September).In terms of biomass, the relative importance of centipedes among other woodland invertebrate predators is high.