Microbial Community Structure and Carbon-Utilization Diversity in a Mine Tailings Revegetation Study

Restoration of metals‐contaminated environments requires a functional microbial community for successful plant community establishment, soil development, and biogeochemical cycling. Our research measured microbial community structure and carbon‐utilization diversity in treatment plots from a mine waste revegetation project near Butte, Montana. Treatments included two controls (raw tailings) either (1) with or (2) without tilling, (3) shallow‐tilled lime addition, (4) deep‐tilled lime addition, (5) lime slurry injection, (6) topsoil addition, and (7) an undisturbed area near the tailings. Microbial community structural differences were assayed by plate counts of heterotrophic bacteria, actinomycetes, fungi, and bacterial endospores, and quantification of arbuscular mycorrhizae colonization. Metabolic diversity differences were assessed by carbon‐utilization profiles generated with Biolog microtiter plates. Heterotrophic bacteria counts were significantly higher in the limed and topsoil treatment plots than the control plots, and the actinomycete and fungal counts increased in the tilled control plot as well. Endospore counts were significantly higher in the topsoil addition and the undisturbed plots than the other treatment plots. Carbon‐utilization activity was very low in untreated plots, intermediate in lime‐treated plots, and very high in topsoil and undisturbed plots. Arbuscular mycorrhizae (AM) colonization levels of two grass species showed low levels of colonization on control, shallow‐limed, and lime slurry‐injected plots, and high levels on the deep‐limed and topsoil‐addition plots. Plant and soil system components increased across the treatment plots, but individual components responded differently to changing environmental conditions.     

芦芽山亚高山草甸、云杉林土壤有机碳、全氮含量的小尺度空间异质性

分析比较了山西芦芽山不同海拔处分布的亚高山草甸（样地A,海拔2756.3 m;样地B,海拔2542.3 m）和云杉林（样地C,海拔2656.8 m;样地D,海拔2387.2 m）土壤有机碳和全氮的小尺度空间异质性特征。结果表明：相同植被类型下海拔较高的样地有机碳含量较高（A：49.84 g/kg,B：38.33 g/kg,C：47.06 g/kg,D：40.67 g/kg）,而较低海拔的样地土壤有机碳含量的异质性较高;除样地A以外的其他3个样地均表现为高度空间依赖性。亚高山草甸土壤全氮含量的异质性远远高于云杉纯林,四个样地中均表现出强的空间自相关性。亚高山草甸样地土壤有机碳和全氮含量均在较大尺度上空间自相关,云杉纯林样地则表现为较小尺度的空间自相关变异。     

Prevalence of parasitism by Amblyomma americanum on wild turkey poults as influenced by prescribed burning.

Captive-raised eastern wild turkey (Meleagris gallopavo silvestris) poults were allowed to forage on either recently burned plots or on plots that had not been burned during the previous 3 years. Following a two hour exposure on the study plots, external parasites were recovered from all poults. The louse (Menacanthus stramineus) and the lone star tick (Amblyomma americanum) were the only parasites recovered. Fifty-nine poults exposed to the burned plots had a significantly (P less than 0.001) lower prevalence of A. americanum infestation than did 57 poults exposed to the unbured plots. Thirty-five percent of the poults exposed to the unburned plots were infested by A. americanum. A single A. americanum was recovered from one poult exposed to burned plots.     

Evaluation of various deployment strategies of imidacloprid-treated spheres in highbush blueberries for control of Rhagoletis mendax (Diptera: Tephritidae)

Biodegradable, ammonium-baited spheres treated with the neonicotinoid insecticide Provado (imidacloprid) at 2% (AI) were evaluated for controlling blueberry maggot flies, Rhagoletis mendax Curran. Three strategies for sphere deployment in highbush blueberries, Vaccinium corymbosum L., were compared with untreated control plots in 1999 and once again compared against control plots and organophosphate insecticide sprays in 2000. The patterns of sphere deployment were as follows: (1) perimeter deployment in which spheres were hung individually and spaced equally around the perimeter of experimental plots; (2) cluster deployment in which four groups of three spheres were hung in equally spaced perimeter locations of experimental plots; and (3) uniform deployment in which spheres were placed 10 m apart (in a grid-like pattern) within experimental plots. In 1999, there were no significant differences in fruit injury levels based on observed R. mendax oviposition scars and reared larvae among plots containing imidacloprid-treated spheres in perimeter, cluster, and internal-grid patterns. However, all plots containing spheres had significantly lower fruit infestation levels (<2%), compared with unsprayed control plots with no spheres deployed, which had infestation levels (>20%). In 2000, there were no significant differences in fruit injury based on observed R. mendax oviposition scars between plots containing imidacloprid-treated spheres in the three deployment strategies tested and plots that received Guthion (Azinphosmethyl) spray applications. However, significantly fewer R. mendax larvae were reared from berries collected from plots that received two applications of Guthion compared with plots in which imidacloprid-treated spheres were deployed. Irrespective of sphere deployment strategies, all sphere-treated and sprayed plots had significantly lower injury levels (<1.5%), based on numbers of reared larvae compared with berries collected from the control plots (>4.0%). Based on captures of flies on unbaited Pherocon AM boards placed in the center of treatment plots, we observed a suppression of R. mendax in plots containing imidacloprid-treated spheres compared with control plots. The potential of using imidacloprid-treated spheres as a behavioral control integrated pest management tactic for blueberry maggot flies is discussed.     

Influence of hop yard ground flora on invertebrate pests of hops and their natural enemies

A 3‐year study in Washington State, USA examined the influence of hop yard ground flora both on the invertebrate pests of hops [including hop aphid (Phorodon humuli Schrank), two‐spotted spider mite (Tetranychus urticae Koch) and hop looper (Hypena humuli Harris)] and on their natural enemies. Each year half of the experimental plots were sown with a mixture of ‘insectary’ plants [including California poppy (Eschscholzia californica von Chamisso), dwarf cornflower (Centaurea cyanus L.) and buckwheat (Fagopyrum esculentum Moench)]. Season‐long average cover provided by the flowering mixture ranged from 2% to 26%, with some blooms being present for most of the season in each year. In terms of vegetation, the other main differences between cover‐cropped and control plots were in the proportions of bare soil (which was always significantly higher in control plots) and the percentage of Chenopodium album L., which was significantly higher in the cover‐cropped plots in two of the three seasons. Populations of spider mites on hop foliage were significantly lower in cover‐cropped plots than in control plots in 2 of 3 years, while mite numbers in the cones at harvest were generally low and usually did not differ between treatments. Responses of hop aphids were much more variable, with no consistent treatment effect on either leaf or cone infestations. Larval populations of hop looper tended to be higher in cover‐cropped plots in the first two generations, but usually not in the third (final) generation. Of the beneficial invertebrates, spiders and nabids consistently reached higher average densities in the ground flora of cover‐cropped plots than in control plots in all 3 years, while anthocorids, geocorids and parasitic hymenoptera reached higher mean densities in the former plots in 2 of 3 years. Adult coccinellids were higher in cover‐cropped plots only in 2006.     

啮齿动物和鸟类对东灵山地区辽东栎种子丢失的影响

20 0 0年 8月中旬至 10月上旬 ,在北京东灵山地区小龙门林场选取两块辽东栎分布近似而坡向不同的样地 ,并对样地内种子库与啮齿动物的种群数量变化进行了调查。结果表明 ,两块样地种子雨持续 4 0天左右 ,且种子下落趋势基本一致 ,高峰期都集中在 9月中旬 ,不同坡向的种子产量差异显著。在两样地随机各设置 2 4个种子方形收集器 (0 5m2 )和 2 0个地表样方 (1 0× 0 5m2 )调查种子产量。通过比较收集器内壳斗和种子数量 ,发现二者无显著差异 ,说明鸟类对林冠层种子丢失作用不明显 ;而收集器和地表样方种子数量差异显著 ,表明辽东栎种子库扩散主要由林中啮齿动物完成。标记重捕发现辽东栎林中啮齿动物群落包括大林姬鼠 ,社鼠 ,棕背鼠平和花鼠 ,其中大林姬鼠为优势种 ,占群落的 77.2 %。     

Cadmium in insects after ash fertilization

Ash fertilization of forests returns nutrients to forest ecosystems and has a positive effect on soil pH, but it also may elevate Cd concentrations of forest biota. Cadmium concentrations of some forest insects ( Formica ants, carabids and Coleopteran larvae from decaying wood) were investigated in southern Finland, where two plots were fertilized with wood ash, while two other plots represented unfertilized control plots. In ants, mean Cd concentration was 3.6 ± 1.4 mg/kg, with nest workers having significantly higher concentrations than workers trapped in pitfall traps. Concentrations at fertilized and unfertilized plots were similar. In carabid beetles, the average Cd concentration of Carabus glabratus was 0.44 ± 0.36 mg/kg, with no significant difference between control plots and fertilized plots. In another carabid beetle, Pterostichus niger , mean Cd concentration was higher at fertilized plots compared to control plots. We conclude that the variation of Cd concentrations in the insects studied is more efficiently controlled by species-specific differences than fertilization history of the forest floor.     

Species Composition of Neotropical Understory Bird Communities: Local Versus Regional Perspectives Based on Capture Data

Species richness and composition of bird assemblages found in the understory of undisturbed Neotropical forests vary at local and regional scales but the extent of that variation has not been well documented. Yet, such variation can be important for understanding patterns of diversity and for conservation. Here, we use capture data from two ca 100-ha study plots (sampled from March 2001 through March 2005) to compare understory assemblages at a local scale; nets on the plots were separated by approximately 1.7 km at the closest point. A total of 157 species (133 per plot) was represented in 6023 captures of 4001 individuals. After eliminating species not likely to be well-sampled with nets, there were 122 species total with 110 and 113 on the two plots, respectively. Species-accumulation curves and abundance-rank relationships were almost identical on both plots. Capture rates were high (53 and 56 birds captured per 100 mist-net-hours, mnh) on both plots. Distributions of species and individuals among families and genera were similar on the two plots but numbers of captures of some common species differed between plots in response to small-scale variation in environmental features. Indicator-species analyses selected seven species as more characteristic of one plot and nine as more characteristic of the other. At the regional level, understory assemblages were most similar to a site in Peru but differed from sites in Brazil, Venezuela, and, especially, Costa Rica. Dissimilarity in species richness per family was related to geographic distance only when Costa Rica was included in the analysis.     

Positive effects of nitric oxide on Solanum lycopersicum

How plant communities are structured, and the relative roles of gradients and disturbances in that structuring, has long been of interest. Here I use plots in replicate tallgrass, mixedgrass, and shortgrass prairies across Northern Oklahoma to address this issue by sampling plant percent cover three years after applying treatments realizing common prairie disturbances of burning, grazing, and soil turnover. I found (1) shortgrass plots had the least amount of aboveground biomass (AGB), with burning and soil turnover plots also having low AGB in the other two prairies, (2) tallgrass plots had the most total cover, with soil turnover plots having the least in the other two prairies, (3) tallgrass plots had the most species, with soil turnover plots having the least in the other two prairies, (4) control plots in mixedgrass had the smallest evenness and plots in shortgrass had the highest, and (5) a high degree of functional similarity in all three prairies. In addition to controlling these different aspects of population and community structure in prairies, results also show that the most severe disturbances can lead to a prairie plant composition and structure more similar to that found in the drier, most western prairie areas.     

The transmission and effect on yield of ryegrass mosaic virus in a filtered air environment

The eriophyid mite vectors of ryegrass mosaic virus (RMV) were excluded from ryegrass by covering plots with a polyethylene film house ventilated by filtered air. Initially plots were manually inoculated to give different levels of RMV. During two seasons no mites were found within the house so that all transmission of virus was by sap. Rolling and frequent cutting of uninfected plots decreased yields, but surprisingly, increasing virus infection did not decrease yields significantly. Cutting transmitted virus within infected plots but not from infected to healthy plots, whereas combined rolling and cutting did transfer virus to healthy plots.     

Response of ground beetle (Coleoptera: Carabidae) field populations to four years of Lepidoptera-specific Bt corn production

Pitfall traps were used to monitor populations of ground beetles (Coleoptera: Carabidae) in plots of corn grown in continuous cultivation during a 4-yr period (2000-2003). Treatments included transgenic corn expressing a Bt Cry protein with efficacy specific against Lepidoptera (Bt), conventional corn grown with insecticide application (I), and the same conventional cultivar grown without insecticide application (NI). Mixed-model analyses of variance were performed on pitfall captures of beetles combined across weeks to give seasonal sums. Effects of corn treatment were not detected (P > 0.05) on total beetle abundance or species richness in any year. Effects of corn treatment on individual taxa were detected (P < 0.05) for 3 of the 39 species-by-year combinations examined. Effects of near significance (P < 0.08) were detected for an additional two species. In 2001, captures of Amara farcta Leconte and Harpalus amputatus Say were lower in Bt plots than in I or NI plots. In 2003, captures of Amara apricaria (Paykull) and Amara carinata (Leconte) were higher in Bt plots than in I or NI plots. Also in 2003, captures of Poecilus scitulus Leconte were higher in I plots than in Bt or NI plots. These patterns were not repeated among years. Results of this study indicate that cultivation of Lepidoptera-specific Bt corn in southern Alberta does not appreciably affect ground beetle populations.     

Development of mass trapping technique for control of brinjal shoot and fruit borer, Leucinodes orbonalis (Lepidoptera: Pyralidae)

Locally-produced clear plastic water traps (12 cm x 14 cm base and 21 cm height) were optimized for use in large-scale mass trapping trials for control of brinjal fruit and shoot borer, Leucinodes orbonalis Guenée. Changing the shape (square and triangular) and number (two and four) of entry holes in the water trap had no significant effect on trap catch. Significantly more male moths were caught in traps treated with water containing powdered detergent than liquid detergent, light gear oil or insecticide. All water traps tested caught significantly higher numbers of moths than sticky delta traps with open sides under farmers' field conditions. Trap catches per 100 m2 were found to increase with increasing number of traps from 3 to 6 but the difference in catch between 4 and 6 traps per 100 m2 was not significant. Two small-scale replicated integrated pest management (IPM) trials were conducted consisting of the optimized water trap placed out with 10 m spacing (4 per 100 m2) and infested shoots pruned and destroyed. The first season trial had two treatments, IPM and farmers' practice in which farmers applied insecticide every two days in the peak harvest period. Overall, the percentage of healthy fruit and yields in both treatments were comparable at 53.8 and 49.6% and 20 and 19.4 tonnes per ha in the IPM and farmers' practice plots respectively. However, the initial infestations in the IPM plots (68%) were significantly higher than in farmers' practice plots (16%) due to the proximity of the nurseries used for the IPM plots to stacks of brinjal crop residues from the previous season that acted as a source of infestation. The second season's trials contained a third treatment in which IPM and farmers' practice were combined. The percent total healthy fruits harvested were 46.1, 58.6 and 69.1% respectively for the farmers' practice, farmers' practice plus IPM and IPM alone. Averaged total fruit yields were approximately 12 tonnes per ha for the farmers' practice plots and 30 tonnes per ha for each of the IPM-treated plots. The IPM plot had significantly fewer infested fruit than the IPM plus farmers practice plots and this was attributed to the activity of the larval parasitoid Trathala flavo-orbitalis (Cameron) that was suppressed in trial plots treated with insecticides.     

An experimental study of translocation success and habitat improvement in wild rabbits

The translocation of wild animals is a strategy frequently used in the conservation and management of natural populations. The aim of this study was to evaluate the impact of translocation (population supplementation) and habitat improvement on the abundance of European wild rabbit Oryctolagus cuniculus . We used eight open plots with different habitat treatments: two with increased shelter, two with increased food, two with increased shelter and food and two without habitat treatment (control plots). We translocated wild rabbits during 3 consecutive years, each year in four of the eight plots, with the remaining plots serving as control for the translocation treatment. Rabbit abundance (translocated plus native rabbits) was calculated by means of pellet counts, and the results were evaluated mainly by generalized linear mixed models. We found that rabbit abundance was determined primarily by habitat improvement. Rabbits were more abundant in treated than in control plots, and most abundant in the plots where food availability was increased. This effect persisted throughout the year. Translocation also increased abundance, but this effect was the strongest where shelter and food had also been improved and declined and disappeared after breeding. These findings suggest that the habitat is an important factor for rabbit abundance, with food availability being the prime factor regulating densities. Moreover, translocations on their own are only effective in the short term in situations in which factors limiting population growth (e.g. disease and predation) have not been corrected. Translocations should be carried out in conjunction with improvements in release habitat as rabbit densities will depend on the maximum carrying capacity of the habitat.     

Effects of irrigation on the seasonal abundance of Empoasca vitis in north-Italian vineyards

The effect of irrigation on the abundance of Empoasca vitis (G?the) populations was investigated in four vineyards located in northeastern Italy. In two experiments, we compared leafhopper population densities in plots irrigated (micro-spray irrigation system) or nonirrigated. In another experiment, we studied the effect of various irrigation systems on E. vitis populations over two successive seasons. In particular, five treatments were compared: control (not irrigated), traditional drip system, three types of subirrigation varying in distance from the row (40, 135, and 95 cm). In this vineyard, stem water potential was monitored with a pressure chamber. E. vitis population densities were affected by irrigation, with higher densities of this pest recorded on irrigated vines. Highest E. vitis densities were detected in drip irrigation plots compared with nonirrigated plots where water stress was highest. Moderate water stress (subirrigation plots) was associated with intermediate leafhopper densities. Implications for integrated pest management are discussed.     

Structure, floristic composition, and vegetation forming factors of three vegetation types in Senegal

Six 1 ha plots were established in a coastal savanna, called Fathala Forest, in Delta du Saloum National Park, Senegal. Two plots were placed in woodland, two in wooded grassland, and two in transition woodland in order to describe structure and floristic composition of the vegetation. All trees ≥ 5 cm dbh were sampled. The three selected vegetation types showed distinct differences in structure as well as in species composition. Woodland had high density (440–449 individuals per ha), many small trees, and high basal area (13.4 m²per ha). Transition woodland was characterised by low density (54–118 individuals per ha) but many large trees and a relatively large basal area (8.6–12.8 m² per ha). Wooded grassland was characterised by medium sized trees, it had low density (86–102 individuals per ha) and low basal area (3.8–5.7 m² per ha). Species richness ranged between 17 and 27 species per ha in the six plots. Only two species were found in all plots, Daniellia oliveri (Caesalpiniaceae) and Prosopis africana (Mimosaceae). Legumes dominated all plots. Wooded grassland and transition woodland had many characteristics of fire-affected vegetation in contrast to woodland. Today wooded grassland encroaches on woodland and transition woodland. Management of the latter two vegetation types should be given priority as they maintain structural and floristic characteristics that are essential to conserve biodiversity and original features of the vegetation, and they are also important for local people who are allowed to make sustainable use of the vegetation.     

The impact of altered precipitation on spatial stratification and activity-densities of springtails (Collembola) and spiders (Araneae)

Abstract.  1. A field experiment was conducted to determine how short-term changes in moisture can alter activity-densities of spiders and springtails.
2. In a Kentucky forest 10 unfenced 4-m² plots were divided into two rainfall treatments. A clear roof over five plots excluded rainfall to simulate severe drought conditions ( drought treatment). Water was sprayed on the five uncovered plots at a rate equal to two times the long-term mean in order to establish the high-rainfall treatment. Activity-densities of Collembola and spiders were measured using pitfall traps designed to sample the top, middle, and bottom layers of leaf litter. The experiment ran from 20 July to 23 September 2001.
3. Overall (i.e. litter layers pooled) activity-density (mean number trapped each sampling date) of Collembola was ≈ 60% lower in drought plots than in plots receiving increased precipitation. Surprisingly, overall spider activity-density was ≈ 1.6 times greater in the drought plots.
4. Differences in rainfall affected the spatial stratification of Collembola and spiders in strikingly different ways. Activity-densities of neither group differed between drought and high-rainfall treatments in the bottom litter layer. Collembola activity-density was three times greater in the top and middle litter layers in high-rainfall plots than in drought plots. In contrast, spider activity-density did not differ between treatments in the top layer, but activity-density was decreased by 50% in the middle layer of high-rainfall plots compared with drought plots.
5. Three Collembola families (Sminthuridae, Tomoceridae, and Entomobryidae) accounted for most of the Collembola pattern. The spider response was due to altered activity-density of one family of wandering spider, the Gnaphosidae.     

Spiders (Araneae) in the biological and integrated pest management of apple in the Czech Republic

Abstract:  Two management systems, biological and integrated, were compared to control the major pest, codling moth ( Cydia pomonella ) in apple orchards. The aim of the study was to assess the effect of these two systems on arboreal spiders. The biological system was based on the use of biological preparations, whereas in the integrated system selective pesticides were employed. The control plot had no pesticide treatment. The abundance of spiders was similar in all study plots during 3 years of study. Diversity, however, was higher in the biological plot than in the control and the integrated plots, suggesting that the response of spiders to management was guild-specific. Four spider families dominanted in all plots: Araneidae (orb weavers), Theridiidae (space-web weavers), and Philodromidae and Thomisidae (ambushers). While Araneidae and Thomisidae were similarly abundant on all plots, the density of Theridiidae and Philodromidae differed. In the integrated plot there were significantly more theridiid spiders, whereas in the control plot philodromid spiders were significantly more abundant. On the biological plot, the two families were similarly abundant. These differences were attributed to different age of trees in the control and treated plots, different prey spectrum, different susceptibility of the two families to applied chemicals and intraguild predation of theridiids by philodromids.     

Overall Versus Band Application of the Nematode Phasmarhabditis hermaphrodita With and Without Incorporation into Soil, for Biological Control of Slugs in Winter Wheat

In two concurrent field experiments, the effects of three types of soil cultivation and two patterns of nematode application were studied in order to investigate their effects on damage to winter wheat by slugs (assessed at Zadoks Growth Stage 12). In experiment 1, infective juveniles (IJs) of the nematode Phasmarhabditis hermaphrodita were applied to soil as an overall spray or as a band spray (8-cm wide), centred on the drill rows (16.7-cm apart). Nematodes were either left undisturbed on the soil surface or harrowed into the soil immediately after application. The control provided by nematodes was compared with that provided by metaldehyde and methiocarb pellets broadcast at the recommended rate immediately after drilling. In this experiment, winter wheat on plots treated with IJs showed significantly less slug damage than on wheat plots treated with metaldehyde or methiocarb pellets or untreated plots. There was no significant difference in plant damage between plots treated with band and overall spray applications of IJs, nor was there any significant difference between plots with and without harrowing. There was also no significant difference between untreated plots and plots treated with metaldehyde or methiocarb pellets, probably because rainfall shortly after treatment rendered the pellets ineffective. In experiment 2, nematodes were applied as an overall spray or plots were not treated with nematodes before soil was cultivated with tines, Roterra or Dutzi cultivators. Nematode application before soil cultivation using tines or Roterra reduced the number of plants damaged significantly. However, nematodes applied before Dutzi cultivation appeared to be rendered ineffective. Damage to winter wheat was lowest in plots that had been sprayed with nematodes and subsequently cultivated with tines or Roterra.     

Changes in Mediterranean plant succession: old-fields revisited

Abstract. Old-field plots used for a study of succession in Mediterranean France were revisited after 12–14 yr. Our aims were: (1) to verify if predicted patterns of species richness, turnover and composition are confirmed; (2) to compare the development in disturbed plots with that in undisturbed ones; (3) to discuss the impact of management changes. In undisturbed plots species richness and turnover decreased with successional age. Floristic composition changed in a way consistent with the predicted successional development in most plots. Therophytes decreased and phanerophytes increased; anemochorous species decreased and endozoochorous species increased, as expected. In plots disturbed since the first analysis richness decreased with successional age, but generally remained higher than in undisturbed plots. Floristic composition, species turnover and an increase in therophytes indicated changes towards younger successional stages. Thus, disturbance changed succession but not much. This is probably linked with the regeneration abilities typical of mediterranean species, e.g. resprouting. At the landscape scale, richness did not change and species turnover was low. The plots studied were situated in two distinct locations. One had not been disturbed between the two observation periods, while the other is a mosaic of undisturbed and disturbed sites. Observations fitted predictions much more closely at the undisturbed location. We conclude that permanent plot studies are powerful in identifying successional trends and can also provide additional insights into the effects of disturbance some of the mechanisms underlying the dynamics of diversity.