Habitat preferences of the larger mammals in the Parambikulam Wildlife Sanctuary,Kerala, India

The habitat preferences of large and medium-sized mammals in the Parambikulam Wildlife Sanctuary were studied. Twenty-four species were recorded. Most prefer to live in specific forest types. In the case of primates, Macaca radiata was more abundant in forest plantations and in deciduous forests. Macaca silenus was cinfined to the evergreen forests alone. Presbytis entellus was more numerous in deciduous forests. Presbytis johni was more or less evenly distributed between the west coast tropical evergreen and moist deciduous forests. Herbivores and carnivores were most abundant in grasslands and in the Tectona grandis plantations.     

Absorption coefficients and mass concentrations of the urban aerosol of Vienna,Austria, during the years 1985 and 1986

Nearly every day aerosol absorption coefficients and mass concentrations were measured at the physics building of the University of Vienna, located approximately 1.5 km from the city center. The aerosol was deposited on Nuclepore filters with 0.2 μm pore size, which were analyzed both gravimetrically for mass concentration c _m and by the integrating plate method for absorption coefficients (σ _a ). The overestimation of the method was corrected for using calibration factors derived from Hitzenberger (1993) and Hitzenberger and Puxbaum (1993). A statistical analysis showed marked seasonal changes of both σ _a and c _m with lowest values in summer (σ _a below detection limit, c _m =21.1 μg/m³) and highest in winter (σ _a =0.574 km^?1, c _m = 543.1 μg/m³).The monthly averages ranged from σ _a =0.014 km^?1 (July 85) to σ _a =0.127 km^?1 (Dec. 85). The monthly mean mass concentration had a low in June 85 (44.5 μg/m³) and a maximum of 159 μg/m³ in February 85. A marked dependence on the wind direction was found for both σ _a and c _m , although the wind directions of the maximum values do not match. An estimate of the black carbon (BC) content using a value of the specific absorption coefficient B _a for BC of 8 m 2/g showed that mean winter BC-concentrations were higher by a factor of 5.2 than in summer, although mass concentrations were increased by only a factor of 2. From seasonal and weekly variation patterns it can be estimated that heavy duty diesel traffic contributes 63 % of the absorbing aerosol in summer. In winter the main BC source is space heating (54 % during the week, 85 % on Sundays); followed by heavy duty traffic (27 % during the week, absent on Sundays). Mean single scattering albedos ω ₀ in winter were as low as 0.70 and in summer as high as 0.94, although individual days had ω ₀ below the critical value of 0.85.     

Diversity, abundance and vertical distribution of methane-oxidizing bacteria (methanotrophs) in the sediments of the Xianghai wetland, Songnen Plain, northeast China

Purpose

Methanotrophs in wetlands are of great importance because up to 90 % of the methane (CH₄) produced in such wetlands could be oxidized by methanotrophs before reaching the atmosphere. The Xianghai wetland of Songnen Plain represents an important ecosystem in northeast China. However, methanotrophic characteristics in this ecosystem have not been studied in detail. The aim of this study is to give an overview of methanotrophic diversity and vertical distribution in the sediments of this important wetland.

Materials and methods

Sediment cores were collected from three freshwater marshes, each dominated by a particular vegetation type: Carex alata, Phragmites australis and Typha orientalis. The diversity of methanotrophs was studied by phylogenetic analysis of both the 16S rRNA gene and the particulate methane monooxygenase (pmoA) gene. Methanotroph abundance was determined by quantitative PCR (qPCR) targeting the pmoA gene; group-specific pmoA gene quantification was also used to estimate the abundance of each methanotrophic group.

Results and discussion

16S rRNA and pmoA gene homological analysis revealed the presence of type Ia, Ib and II methanotrophs. Novel pmoA sequences distantly affiliated to cultured Methylococcus sp. were detected, implying the existence of novel methanotrophs in the wetland. Most obtained representatives of Methylobacter genus (both 16S rRNA and pmoA genes) were closely clustered in relation to sequences acquired from the Zoige wetland, Tibet and Siberia permafrost soils, therefore suggesting methanotrophs belonging to Methylobacter genus shared characteristics with methanotrophs in cold areas. The dominance of type I methanotrophs (especially the Methylobacter genus) was detected by both clone library analysis and group-specific qPCR assay. The relatively high methanotroph diversity and pmoA copy numbers measured in the T. orientalis marsh sediments indicated that vegetation type played an important role during CH₄ oxidation in the wetland.

Conclusions

We present the first data set on methanotroph diversity and vertical distribution in the sediments of the Xianghai wetland. DNA sequences information of Methylococcus-like methanotrophs in the wetland will facilitate the isolating of novel methanotrophs from the wetland. In a worldwide context, our study has enriched the database of genotypic diversity of methanotrophs, which will help in the understanding of the geographical distribution of methanotrophic communities.     

Population dynamics of the mycoparasite, sporidesmium sclerotivorum, and its host, sclerotinia minor, in soil

The infection and survival of sclerotia of Sclerotinia minor and the production ofmacroconidia of the mycoparasite, Sporidesmium sclerotivorum, were studied in vitro when each fungus was added to soil at various initial inoculum densities. The rate at which S. sclerotivorum invaded host sclerotia and caused their decay varied with the amount of the mycoparasite added to soil. The results suggest that approximately 5 macroconidia of the mycoparasite g^?1 of soil are needed to successfully infect sclerotia and bring about their decay, when soils are sampled and mixed every 2 weeks. The rate at which S. sclerotivorum infects sclerotia of S. minor and causes their decay is also dependent on the initial inoculum density of the host. Each infected sclerotium supports the production of about 15,000 new macroconidia in soil regardless of the initial inoculum density of the host. It is concluded that successful biological control by S. sclerotivorum is dependent on the soil population of both the host and the mycoparasite.     

An analysis of the role of local fishermen in the conservation of the loggerhead turtle (Caretta caretta) in Pontal do Ipiranga, Linhares, ES, Brazil

The role of researchers and fishermen in the clutch management of loggerhead sea turtles was evaluated for 10 nesting seasons at Pontal do Ipiranga TAMAR station, Linhares, ES. The comparison of nests transferred by researchers and locals (carebeiros) showed that clutches transferred by researchers presented higher clutch size. Clutch size between nests transferred by carebeiros and left in situ did not show significant differences. Hatching success was significantly higher for clutches left in situ than for those transferred to other places in the beach or to hatcheries. The clutches transferred exclusively by researchers achieved a higher hatching success than those transferred partially or totally by carebeiros. The relocation time of clutches collected by carebeiros and handed to researchers affected hatching success. It is recommended that clutches be left in situ, provided they have adequate conditions for monitoring, but careful clutch translocation, independent of the interval elapsed after laying, may also constitute a viable technique for the conservation of sea turtles in the region.     

Invasions of the Portuguese millipede,Ommatoiulus moreleti,in southern Australia

The Portuguese millipede, Ommatoiulus moreleti, was first recorded in Australia on Eyre Peninsula, South Australia in 1953. By the early 1980s, O. moreleti had spread to several sites across southern Australia where it had become a significant nuisance pest invading houses in large numbers in autumn and spring. At that time, it was predicted that O. moreleti would further expand its distribution to occupy most areas of southern Australia with mean annual rainfall of 300–2400 mm (excluding areas with summer rain maxima), mean daily minimum air temperatures in winter of 0–15 °C and mean daily maximum temperatures in summer of 18–33 °C, based on climatic matching of where it had already spread to. This paper reports the known distribution of O. moreleti in Australia in 2013 and confirms the earlier prediction. Whilst stadial age and body size (width) of O. moreleti now vary greatly between individual sites in Australia, geographic scale patterns in these traits are slight, with both age and size only weakly correlated with rainfall and temperature. Millipedes are smaller in Australia compared with Portugal. The importance of this size variation is discussed with reference to its likely influence on fecundity and the success of an introduced biological control agent (Pelidnoptera nigripennis: Diptera, Sciomyzidae).     

Effects of white-tailed deer on the native earthworm,Eisenoides carolinensis,in the southern Appalachian Mountains,USA

Research on earthworms in North America has focused on the effects of invasive earthworms, with few studies examining the ecology of native earthworm species. Deer have been shown to influence belowground processes through grazing, trampling, and fecal pellet deposition. We proposed that native earthworms in an oak-dominated forest in Virginia might benefit from increased organic matter provided by deer fecal material. We examined potential interactions between a common aboveground herbivore, the white-tailed deer (Odocoileus virginianus), and earthworms using laboratory and field experiments. In our laboratory experiment, we found that a native earthworm, Eisenoides carolinensis, and an invasive earthworm, Lumbricus terrestris both fared better in treatments with deer pellets compared with the treatment with leaf litter alone. In our field experiment, we used fences to exclude deer from six plots and left twelve plots unfenced to explore the effects of deer activity on earthworm biomass and density. We also examined the effects of deer on soil and vegetation characteristics. After three years, the amount of herbaceous cover was higher on fenced plots compared with unfenced plots. Although we found no other differences for vegetation and soil characteristics between fenced and unfenced plots, many of these variables were important as covariates in our models examining the effect of deer exclusion on earthworms, indicating plot-level (as opposed to treatment-level) variation in these variables. All identifiable earthworms were either E. carolinensis or Diplocardia spp. (both native species), with E. carolinensis making up 90% of the specimens. The total biomass of earthworms, as well as the biomass and density of adult and small juvenile earthworms, was greater on unfenced plots with deer activity compared with fenced plots. This study highlights the importance of above- and below-ground interactions in forest ecosystems by showing that E. carolinensis appears to benefit from the presence of deer and adds to our sparse knowledge of the ecology of this native earthworm.     

Soil invertebrates and the degradation of vanillin,cinnamic acid,and lignins

A range of 8–25% of fed cinnamic 2-[¹⁴C] acid and 9–14% of injected vanillin 5-[¹⁴C] were oxidised to ¹⁴CO₂ at 15 C over 7 and 6 days respectively in an isopod, Oiuscus asellus; a millipede, Pseudopolydesmus serratus; a slug, Deroceras reticulatum; a snail, Oxychilus draparnaldi; and an earthworm, Eisenia foetida. Approximately 2–10% of nonmetabolised and 13–48%, of metabolised vanillin were present in the animal tissues after 6 days. Correspondingly. 1–4% and 22–66% of these materials were found in egesta.A millipede (Oxidus gracilis), O. asellus. D. reticuluttum. O. draparnaldi, and E. foetida were found unable to degrade ring [¹⁴C]-, methoxy [¹⁴C]- and side chain [¹⁴C]-lignin to ¹⁴CO₂ over 10 days, thus providing very strong evidence that these invertebrates are incapable of degrading liginin.     

Effect of land use on the denitrification, abundance of denitrifiers, and total nitrogen gas production in the subtropical region of China

The potential denitrification (PD) rate, NO, N₂O, and N₂ emission were determined after treatment with 50 mg NO₃ ^??N kg^?1 soil using the acetylene inhibition method, and meanwhile abundance of four denitrifying genes (i.e., narG, nirK, norB, nosZ) was also investigated in subtropical soils of China. Soil samples were collected from conifer forest (C), shrub forest, and farmland. These soils were derived from Quaternary red earth and granite. The PD rate and N gas emissions significantly (p?<?0.05) differed between forest and farmland soils; abundance of denitrifying genes was also significantly affected by the land-use change. Correlation and multiple stepwise regression analyses showed that the PD rate was significantly (p?<?0.05) and positively correlated with soil pH but not with soil organic C and total N contents (p?>?0.05). The norB gene copies in farmland soils were significantly higher than in conifer and shrub forest soils (p?<?0.01). Both norB and nosZ gene copies were linearly correlated with soil pH, and the PD rate and N₂ emission rate were significantly correlated with the abundance of norB (p?<?0.05). Probably, soil pH affected denitrifiers targeted by the norB gene, thus decreasing the reduction of NO and N₂O.     

Studies on the impact of paths on the dune vegetation at Winterton,Norfolk, England

A study was made of paths on a dune system at Winterton, Norfolk, by ground and aerial surveys and a map produced of the 35 km of major paths in 104 ha of dune. Experiments were carried out on the resistance to trampling of a tall Festuca ovina-Carex arenaria sward. Estimates were made of the comparative vulnerability of other plant communities. The range extended from Ammophila arenaria, which was 10 x as vulnerable, to a short rabbit-grazed sward, only $\text{1}\text{3}\text{?}\text{1}\text{4}\text{x}$ as vulnerable. The more vulnerable habitats unfortunately attract more people. 42% of the paths at Winterton occur on the steep slopes dominated by Ammophila. Comparisons are made with a similar site at Meijendel where greater recreational pressure necessitated laid-out paths and fencing to control visitors. It is suggested that if visitor pressure increases at Winterton, similar management may also be required there.     

Harvesting, local trade, and conservation of parrots in the Northeastern Peruvian Amazon

In some places of the northeastern Peruvian Amazon the harvesting and local trade of parrot nestlings is still a common practice (loreada) that takes place every year between February and April, despite being banned by the national laws. Between 1996 and 1999, I monitored the use of these birds in 3890-ha of Mauritia flexuosa-palm swamps, located close to the village of Victoria (Loreto, Peru). Seven species of parrots were collected by local poachers in the study area, with Amazona amazonica (61.1% of the captures) and Ara ararauna (25.9%) the most commonly harvested. The total number of nestlings taken during the 4-year study period was 1718, ranging from 680 birds harvested in 1996 to 166 in 1998. The two methods used to collect nestlings, cutting down the nesting tree or opening a hole in the trunk to reach the nest cavity, are not sustainable because nest-trees become useless and the next generation is completely removed. The analyses of demographic data and annual harvest rates suggest that at least three species (Ara ararauna, Ara macao and Amazona amazonica) are being over-harvested and may be seriously threatened in the long term.     

Ecological influence of the entomopathogenic nematode,Steinernema carpocapsae,on pistachio orchard soil arthropods

The entomopathogenic nematode, Steinernema carpocapsae, can reduce pesticide reliance in pistachios by controlling overwintering larvae of the navel orangeworm, Amyelois transitella (Lepidoptera: Pyralidae). But, beyond this, their influence in pistachio soil food webs is unclear. Given soil food webs’ complexity, S. carpocapsae likely interact with more species than just their intended target, infecting alternate hosts or providing food for native predators. This study quantifies the nematodes’ effects on soil arthropod and surface arthropod diversity in two large orchards in Madera County, California. We found significantly more isotomid collembolans, predatory anystid mites and gnaphosid spiders under trees where nematodes were applied indicating either direct predation or indirect trophic effects. Significantly fewer Forficula auricularia (Dermaptera: Forficulidae) and Blapstinus discolor (Coleoptera: Tenebrionidae) were found under treated trees, suggesting a possible non-target infection. Nematode persistence was limited but positively correlated with pitfall catches of the tenebrionid beetles, Nyctoporis cristata and B. discolor.     

Population number, viability, and taxonomic composition of the bacterial nanoforms in iron-manganic concretions

It is shown for the first time that a significant part of the bacteria (up to 40%) in the iron-manganic concretions of soddy-podzolic and soddy meadow soils are represented by nanoforms; their number reaches 600–700 million cells/g. Judging from the specific luminescent coloration, the fraction of viable cells among the bacterial nanoforms is very high in the concretions and amounts up to 88–99%. For the first time, the following phyla were identified among the bacterial nanoforms in the concretions with the use of the FISH method: Alphaproteobacteria, Betaproteobacteria, Gammaproteobateria, Deltaproteobacteria, Acidobacteria, and Planctomycetes. The Gammaproteobacteria phylum predominated in the concretions from the soddy-podzolic soil, and the Deltaproteobacteria phylum predominated in the concretions from the soddy meadow soil. In the alluvial meadow soil, the Alphaproteobacteria, Betaproteobacteria, and Acidobacteria phyla were found. The significant number and portion of bacterial nanoforms in the concretions, their high vitality, and their taxonomic diversity allow us to conclude that the bacterial nanoforms play an important role in the processes taking place in the concretions.     

The Uptake of Copper by Aldama dentata: Ecophysiological Response, Its Modeling, and the Implication for Phytoremediation

Aldama dentata Llave & Lex. is a plant native to Latin America that exhibits metallicolous populations. Its ecophysiological (EP) response to Cu stress, administered as graded soil concentrations (C _s) of the fungicide copper(II) oxychloride, is examined in depth. Using a systems biology- and population dynamics-inspired approach, an r/K-driven model is proposed that satisfactorily explains the plant Cu concentration (C _p) versus C _s EP response curves for the root, shoot, and whole plant. A. dentata was found to be a Cu excluder (ME). The dual role of Cu as a nutrient and toxin at low and high concentrations, respectively, manifested as a parabolic variation of the foliar area where the toxicity appeared as a second-order effect. The power-law variance of biomass (B _p) with C _p expected from the universal allometric scaling law of biology was loosely followed and is discussed in terms of the mode of Cu uptake by the plant and Cu??s dual physiological role. Biometric growth indices reflected the impact of Cu on the photosynthetic energy harvest. The general applicability of the r/K-driven model was corroborated by its successful application to the published C _p?CC _s data of the well-known Cu ME, Silene vulgaris. The r?CK factors suggest a new quantitative manner of comparing the phytoavailability of the metal and the plant??s accumulation capability across soil types. A. dentata with high root C _p but low B _p diminution could potentially find use as a Cu phytostabilizer.     

Wood, nematodes, and the nematode-trapping fungus Arthrobotrys oligospora

Researchers have proposed that Arthrobotrys oligospora and related fungi trap soil nematodes to obtain nitrogen and thereby compete saprophytically for carbon and energy in nitrogen-poor environments, including litter and wood. The current study tested two hypotheses concerning this model. The first was that wood decomposition would be enhanced if both large numbers of nematodes (a potential nitrogen supply) and A. oligospora (a cellulolytic organism that can use that N supply) were present. The second was that A. oligospora trapping activity would increase if large numbers of nematodes were added to soil containing abundant carbon (a wood dowel or chip). Although the first hypothesis was supported by an in vitro experiment on agar (A. oligospora degraded much more wood when nematodes were present), neither hypothesis was supported by an experiment in vials containing field soil. In soil, wood decomposition was unaffected by the addition of A. oligospora or large numbers of nematodes. Whereas A. oligospora trapped virtually all nematodes added to agar cultures, it trapped few or no nematodes added to soil. Given that the fungal isolate was obtained from the same soil and that the fungus increased to large numbers (>1×10³ propagules g⁻¹ soil), the failure of A. oligospora to trap nematodes in soil is difficult to explain. Soil nitrate levels, however, were high (71 mg kg⁻¹), and it is possible that with lower nitrate levels, trapping in soil might be stimulated by wood and nematodes.     

The impact of harvester ants on decomposition, N mineralization, litter quality, and the availability of N to plants in the Mojave Desert

In arid areas of North America, nests of the seed-harvesting ant Pogonomyrmex rugosus tend to be elevated in mineral nitrogen and other soil nutrients relative to other microhabitats. We investigated the roles of decomposition, N mineralization, and plant nutrient uptake in maintaining high standing stocks of nutrients in P. rugosus ant nests. Decomposition rates of standard cellulose substrates placed on the surface of ant nests and other desert microhabitats suggest that conditions found in ant nests and bare areas are conducive to higher rates of decomposition than conditions under shrubs. In laboratory incubations of moist soil, net N mineralization rates were significantly higher in soil from ant nests than from bare areas and under two of three plant species. Net N mineralization rates measured in situ were much lower than those measured in laboratory incubations, but ant nest soil still exhibited higher rates at one of two sites. Litter collected from ant mounds, composed chiefly of seed chaff, was similar in N content to litter collected from underneath the dominant plant species, but had a significantly higher mean δ¹⁵N. Using this distinctive isotope signature as a tracer, we found no evidence that large perennial shrubs tap ant nests as a source of N. An invasive, annual grass species was significantly enriched in ¹⁵N, had higher leaf %N, and produced more seeds when growing on the mound than when growing several meters away; however P. rugosus nest surfaces are typically free of such annuals. We conclude that both high rates of nutrient cycling relative to other Mojave Desert microhabitats and low N utilization by the surrounding vegetation contribute to high standing stocks of mineral N in P. rugosus nests.     

Heathland management in the New Forest,Hampshire, England

Heathland in the New Forest, Hampshire, England, is subject to systematic controlled burning, the main intention of which is to maintain and enhance the quality of the grazing for commoners' animals. Mature heathland vegetation is richer in bird, reptile and invertebrate life than younger age classes. However, a survey has confirmed that despite a recent reduction in the area burnt annually, burning had produced an imbalance in favour of young age classes of heather Calluna vulgaris and Erica spp., and that intensive browsing after fire was severely inhibiting the regeneration of gorse Ulex europaeus. The data obtained made it possible to recommend management policies which attempted to correct the imbalance in vegetation age structure and also satisfied the requirements of the grazier.     

Use of Spinach, Radish, and Perennial Ryegrass to Assess the Availability of Metals in Waste Foundry Sands

Opencast coalmine effluent contains higher concentrations of Cd, Cr, Co, Ni and Pb. Biofiltration of these metals has been demonstrated successfully with the help of aquatic macrophytes i.e., E. crassipes, L. minor and A. pinnata. Experiments revealed E. crassipes reduced highest concentration of heavy metals followed by L. minor and A. pinnata on 20th days retention period. Plant tissue analysis revealed higher accumulation of metals in roots than leaves. Highly significant correlations have been noted between removal of heavy metals in effluent and their accumulation in roots and leaves of the experimental sets. Translocation factor also revealed lower transportation of metals from root to leaves. Reduction in chlorophyll and protein content was noted with the accumulation of heavy metals. N, P and K analysis in plant tissues indicated continuous decrease in their concentration with increasing metal concentration. Negative and significant correlations between metal accumulation and N, P and K concentrations in plant tissues showed adverse effects of heavy metals. Analysis of variance (Dunnett t-test) showed significant results (p?<?0.001) for all the metals in different durations.     

Co-introduction of exotic rhizobia to the rhizosphere of the invasive legume Acacia saligna,an intercontinental study

Invasive woody legumes have profound impacts in the nitrogen content and cycling of invaded ecosystems due to the ability to enter into symbiosis with nitrogen-fixing bacteria. In spite of the relevance of this symbiosis, the identity and origin of the symbionts involved in invasion are not well understood. We conducted a study to assess the diversity of symbiotic root-nodulating bacteria associated with the invasive Acacia saligna, in newly colonized areas in Portugal and Australia. BOX-PCR was used to discriminate the isolated bacteria and 16S rRNA and nifD genes were sequenced to identify the different isolates and their geographic origin. Bradyrhizobium and Mesorhizobium nodulated A. saligna in Australia while only Bradyrhizobium spp. were found in Portugal. The dominant strains nodulating A. saligna were related to Bradyrhizobium liaoningense and Bradyrhizobium canariense. Co-occurring Acacia longifolia and A. saligna in Australia harbor different rhizobial communities. As an example, we found Mesorhizobium sp. and Phyllobacterium trifolii in A. saligna and A. longifolia respectively, being this the first report for this association. The analysis of the phylogeographic marker nifD clustered most of the sequences obtained in this study with sequences of Australian origin, indicating that exotic bradyrhizobia might have been co-introduced with A. saligna in Portugal. This result highlights the risks of introducing exotic inoculants that might facilitate the invasion of new areas and alter native soil bacterial communities, hindering the recovery of ecosystems.