Combined influence of food level and inoculation density on competition between <Emphasis Type="Italic">Anuraeopsis fissa</Emphasis> and <Emphasis Type="Italic">Brachionus patulus</Emphasis> or <Emphasis Type="Italic">Brachionus macracanthus</Emphasis> (Rotifera: Brachionidae)

We tested separately the effect of two taxonomically related rotifers (B. patulus and B. macracanthus) on the population dynamics of another species (A. fissa) at low (0.5 ×10 ⁶) and high food levels (1.5 × 10⁶ cells/ml of Chlorella vulgaris) using different inoculation densities (0–100%). We also quantified the impact of A. fissa on the two brachionid species. Regardless of the presence of the competing species, an increase in the availability of food led to increase in the abundances of the three rotifers. The population growth of B. patulus, B. macracanthus, or A. fissa was affected negatively when cultured together with another species. An increase in the initial density of any one of the competing species became advantageous to maintain a certain population size. At a low algal food level, B. patulus was able to suppress A. fissa more strongly than B. macracanthus. On the other hand, at a high food level, B. macracanthus suppressed the population of A. fissa more strongly than B. patulus. Peak population densities for A. fissa varied from about 150 to 1000 ind./ml, depending on food density and the presence of competitors. The rate of population increase (r) of A. fissa, B. patulus, and B. macracanthus increased with an increase in food availability but decreased with increasing initial density of the competitor. Both Brachionus spp. experienced negative growth rates in the presence of A. fissa, especially at a high initial density of the latter. Published in Russian in Ekologiya, 2007, Vol. 38, No. 5, pp. 381–390. The article was submitted by the authors in English.     

The Spatiotemporal Structure of Rodent Populations in the Steppe Zone of Western Siberia

The spatial structure of populations has been studied in two rodent species inhabiting the subzone of meadow steppes of the steppe zone of Omsk oblast: the narrow-sculled vole (Microtus gregalis Pall.) and steppe lemming (Lagurus lagurus Pall.). Their populations are represented by combinations of territorial family groups whose structure and spatial distribution vary by season depending on population density, the phase of the population cycle, and the status of their members in the population. In the areas cohabited by M. gregalis and L. lagurus, the pattern of territory use and the rhythm of animal activity during the day depend primarily on their total density: under conditions of low density, the population groups of both species are spatially separated; at increased density, they are distributed with respect to the pattern of daily activity. Both species jointly use part of the territory but at different times of day: M. gregalis, mainly at night and in the morning; L. lagurus, in the daytime.     

Spatial population structure in forest voles of the genus <Emphasis Type="Italic">Clethrionomys</Emphasis> in the southern taiga of the Middle Irtysh region

A comparative analysis of spatial population structure in the northern red-backed vole (Clethrionomys rutilus Pall.) and large-toothed red-backed vole (Cl. rufocanus Sund.) has been performed in the middle taiga zone of the Middle Irtysh region (Omsk oblast). Populations of these species are represented by sets of territorial groups whose numbers and spatial distribution change from year to year depending on the ratio of these species in a biotope and their population density. There is no significant interspecific competition between cohabitant Cl. rutilus and Cl. rufocanus. In particular, this follows from the fact that the population density and distribution pattern of one species are independent of those of the other species. It has been found that the size of home ranges in Cl. rutilus inversely depends on its population density, with that in Cl. rufocanus remaining approximately the same at different population densities, and that the structure of the resident part of the population in both species changes during the season, as voles from neighboring habitats or dispersing voles settle in the study area.     

Sustainable Exploitation of Borassus aethiopum, Elaeis guineensis and Raphia hookeri for the Extraction of Palm Wine in Côte d'Ivoire

In the rural areas of developing countries palms are major sources of many products. One of these is palm wine, which has an important role for nutrition, income and social life. In the Côte d'Ivoire (West Africa), palm wine is extracted from three different species: Borassus aethiopum Mart., Raphia hookeri Mann & Wendland and Elaeis guineensis Jacq. As the extraction methods are destructive, palm stands are locally threatened by extinction. This could have serious consequences not only for the nutritional situation of the population but also for their income. Field visits were conducted in order to assess the degree of sustainability of palm wine extraction in eight villages of Côte d'Ivoire's three major agro-ecozones. Based on the annual palm wine need for consumption and commercialisation and on the availability of palms, a sustainability index was calculated for each palm species in each village. The occurrence of palm trees depends on the vegetation type. B. aethiopum is a typical savanna tree (> 20 palms per hectare) and is almost absent in other vegetation types. In 75% of the villages the exploitation of B. aethiopum is not sustainable. The preferred vegetation type for R. hookeri is the forest along the rivers (> 33 palms per hectare) compared to the other vegetation types of the forest zone (< 5 palms per hectare). Due to the high preference for the palm wine of this species its exploitation is not sustainable in any of the selected villages. The distribution of E. guineensis depends mostly on human activities, the main vegetation types being plantations (34 palms per hectare), fallow land and cultivated fields (15 palms per hectare) and the forest along the rivers (31 palms per hectare). The exploitation of this species is in general sustainable throughout all ecozones with some rare exceptions.     

Effect of interspecific competition on functional properties of plants in mountain-steppe communities of the Gobi

The isotope ratios δ¹³C and δ¹⁵N and the contents of nitrogen, carbon, and mineral substances have been studied in the leaves of Ephedra sinica, Allium polyrhizum, and Stipa glareosa plants growing separately or together under arid conditions of the Gobi (Mongolia). The contents of nitrogen, mineral substances, and δ¹⁵N have proved to decrease when these species grow together, providing evidence that they compete for environmental resources. The nitrogen content decreases to the greatest extent in E. sinica due to the low competitiveness of this species. The direction of change in δ¹³C in E. sinica is opposite to that in A. polyrhizum and S. glareosa. Differences in physiological mechanisms of adaptation to stress between these species provides a basis for attributing them to different functional groups and for predicting the result of their competition upon changes in climatic conditions.     

Interrelations of Epibiontic Microalgae and Crustacean Zooplankton under Conditions of a Blooming Eutrophic Water Body

The possibility of symbiotic, mutualistic (++) interrelations between epibiontic microalgae (Characidiopsis ellipsoidea, Colacium vesiculosum) and cyclopoids (Cyclops vicinus, Mesocyclops leukarti) in the Bugach recreational reservoir with a bloom of cyanobacteria is demonstrated. Overgrown cyclopoids, compared to those free from microalgae, have advantages in oxygen supply, which may be insufficient in the period of intensive algal bloom. Calculations have shown that oxygen requirements of cyclopoids may be fully satisfied due to C. vesiculosum photosynthetic activity in the dysphotic zone if the density of overgrowth exceeds 1000 algal cells per individual. There is no significant correlation between the natural mortality of crustaceans and the indices of their overgrowth by microalgae.     

Changes in Vegetation Cover and Socio-Economic Transitions in a Coastal Lagoon (Kalametiya, Sri Lanka), As Observed by Teledetection and Ground Truthing, Can be Attributed to an Upstream Irrigation Scheme

According to some non-scholarly reports, Kalametiya lagoon (dry zone of southern Sri Lanka, formerly 8.9 km², now 7.5 km²) had been a moderately or high salinity water body and a very important centre of prawn fishery until the late 1960s. Most of the lagoon area had remained open water until then. An upstream irrigation project, the Udawalawa irrigation scheme, came into operation in 1967, increasing the freshwater inflow to the lagoon. The flora, fauna and water quality of the lagoon was reported to have changed since then.The lagoon now is a shallow coastal water body with low salinity water. More than 75% of the lagoon is covered by freshwater species or mangrove species characteristic for water with a low salinity: Eichhornia crassipes, Typha latifolia resp. Sonneratia caseolaris. There is actually no commercially important fishery in the lagoon.The present study was carried out to assess scientifically the said changes in the vegetation within a GIS, using aerial photographs taken in 1956 and 1994 and IRS IC, PAN+LISS III satellite images of 1997 in combination with ground surveys and information from a questionnaire-based survey.It appeared from this work that the aerial cover by Sonneratia caseolaris has increased by more than 30 times over the period from 1956 to the recent dates. Also, the lagoon area with open water has been drastically reduced during the same period as a result of spreading of freshwater and low salinity plant species. The results strongly suggest that the locally reported changes (fisheries decline, water salinity decrease) can be corroborated by the observed profound changes in plant cover and that upstream water works may have had strong impacts on this ecosystem, thus causing these changes.This study couples data obtained from retrospective aerial photograph series, from spaceborne imaging, from actual ground surveys and from questionnaires amongst elderly people to reconstruct decadal environmental change, thus attempting to fill the gap of lacking historical environmental data.     

Phytoremediation of Nickel-Contaminated Soils by Brassica Species

Two Brassica species Brassica juncea and Brassica carinata of the Indian mustard, were grown in an artificially Ni-contaminated soil to study the tolerance and Ni accumulation. Chelating agent, EDTA was applied at the rosette stage for enhancing the metal uptake. Nickel concentration over almost double that in control was observed in both the species with Ni contamination along with EDTA application. Specie B. juncea appeared to be slightly more tolerant and higher accumulator of Ni. In agreement with the earlier reports, the translocation of the pollutant metal to the shoot from the root seemed to be restricted in both of Brassica species at higher rate of Ni application plus EDTA. The results of the present study indicated that B. juncea has the potential to be hyperaccumulator of Ni.     

Host Specificity of Flukes of the Genus Sphaerostomum (Trematoda: Opecoelidae) within Their Geographic Ranges

The host specificity of flukes belonging to the genus Sphaerostomum (S. bramae and S. globiporum) in the center and at the periphery of the genus range is discussed. Both fluke species are specific parasites of cyprinids. However, fish of nine other families and one cyclostome species have also been recorded as their hosts. At the periphery of the range, the spectrum of definitive hosts is broader than in the center owing to a greater number of unspecific hosts. In the center, unspecific hosts are represented by six fish species (Esox lucius, Misgurnus fossilis, Perca fluviatilis, Lota lota, Gymnocephalus cernuus, and Salmo sp.), four of which are predators. At the periphery, 11 fish species, including six predators (Anguilla anguilla, Barbatula barbatula, Cottus gobio, Cobitis taenia, Coregonus lavaretus, Salmo trutta, Alosa sp., Potamoschistus minutus, E. lucius, P. fluviatilis, and L. lota), and the cyclostome Lampetra fluviatilis are unspecific hosts. In the peripheral populations, compared to central, flukes manifest greater adaptive plasticity and can infest new hosts.     

Intake of ²³⁸U and ²³²Th through the consumption of foodstuffs by tribal populations practicing slash and burn agriculture in an extremely high rainfall area

The concentration of naturally occurring radionuclides ²³²Th, ²³⁸U was determined using Instrumental Neutron Activation Analysis (INAA) in different food groups namely cereals, vegetables, leafy vegetables, roots and tubers cultivated and consumed by tribal population residing around the proposed uranium mine. The study area is a part of rural area K. P. Mawthabah (Domiasiat) in the west Khasi Hills District of Meghalaya, India located in the tropical region of high rainfall that remains steeped in tribal tradition without much outside influence. Agriculture by Jhum (slash and burn) cultivation and animal husbandry are the main occupation of the tribal populations. A total of 89 samples from locally grown food products were analyzed. The concentration of ²³⁸U and ²³²Th in the soil of the study area was found to vary 1.6-15.5 and 2.0-5.0 times respectively to the average mean value observed in India. The estimated daily dietary intake of ²³⁸U and ²³²Th were 2.0 μg d⁻¹ (25 mBq d⁻¹) and 3.4 μg d⁻¹ (14 mBq d⁻¹) is comparable with reported range 0.5-5.0 μg d⁻¹ and 0.15-3.5 μg d⁻¹ respectively for the Asian population.     

Effect of Flavonoids on the Ecology of Enterobacteria

The effect of flavonoids, natural plant metabolites, on the growth and viability of enterobacteria was studied using S. typhimurium and E. coli strains defective in some components of the DNA repair system. The minimal inhibitory concentrations of several flavonoids were measured. These agents were shown to have a weak bactericidal and a marked bacteriostatic effect, the latter increasing under anaerobic conditions. It is proposed that the mechanism of the bacteriostatic action of flavonoids is based on topoisomerase II inhibition. On the basis of these results, the ability of flavonoids to differentially suppress bacterial growth and their probable influence on the ecology of microorganisms (the formation, species composition, and ecological balance of natural microbial communities) are discussed.     

210Po in the marine environment with emphasis on its behaviour within the biosphere

The distribution and behaviour of the natural-series alpha-emitter polonium-210 in the marine environment has been under study for many years primarily due to its enhanced bioaccumulation, its strong affinity for binding with certain internal tissues, and its importance as a contributor to the natural radiation dose received by marine biota as well as humans consuming seafoods. Results from studies spanning nearly 5 decades show that ²¹⁰Po concentrations in organisms vary widely among the different phylogenic groups as well as between the different tissues of a given species. Such variation results in ²¹⁰Po concentration factors ranging from approximately 10³ to over 10⁶ depending upon the organism or tissue considered. ²¹⁰Po/²¹⁰Pb ratios in marine species are generally greater than unity and tend to increase up the food chain indicating that ²¹⁰Po is preferentially taken up by organisms compared to its progenitor ²¹⁰Pb. The effective transfer of ²¹⁰Po up the food chain is primarily due to the high degree of assimilation of the radionuclide from ingested food and its subsequent strong retention in the organisms. In some cases this mechanism may lead to an apparent biomagnification of ²¹⁰Po at the higher trophic level. Various pelagic species release ²¹⁰Po and ²¹⁰Pb packaged in organic biodetrital particles that sink and remove these radionuclides from the upper water column, a biogeochemical process which, coupled with scavenging rates of this radionuclide pair, is being examined as a possible proxy for estimating downward organic carbon fluxes in the sea. Data related to preferential bioaccumulation in various organisms, their tissues, resultant radiation doses to these species, and the processes by which ²¹⁰Po is transferred and recycled through the food web are discussed. In addition, the main gaps in our present knowledge and proposed areas for future studies on the biogeochemical behaviour of ²¹⁰Po and its use as a tracer of oceanographic processes are highlighted in this review.     

Distribution Of Cadmium And Nickel Among Various Forms In Natural And Contaminated Soils Amended With Edta

Because of its strong chelating capacity, application of ethylenediaminetetraacetic acid (EDTA) to soils may change the amount and distribution of heavy metals among their various chemical forms. Therefore, a greenhouse experiment was conducted using two cultivars of Brassica species (Brassica juncea and Brassica carinata) as hyper accumulator test crops on natural and artificially Cd and Ni contaminated soils. Both natural and metal amended soils were treated with disodium salt of EDTA at 0 and 1 g kg^–1 soil. After harvest of crops, soil samples were fractionated into water soluble plus exchangeable (WE), carbonate (CARB), organic matter (OM), Mn oxide (MnOX), amorphous Fe oxide (AFeOX), crystalline Fe oxide (CFeOX) and residual (RES) fractions. In metal amended soils, Cd and Ni were found predominantly in the AFeOX fraction in the absence of EDTA application and in the WE fraction in EDTA treated soil. Application of EDTA resulted in the redistribution of Cd among different forms and increased significantly Cd in the WE fraction with a concomitant significant decrease in the OM fraction. In natural soils, more than 40% of the total Cd was present in the RES fraction while in contaminated soil it was only 5%. Nickel in the WE fraction increased significantly while it considerably decreased in the CARB, OM, MnOX, AFeOX and CFeOX fractions with EDTA addition. This indicated that applied EDTA is capable to move Cd and Ni from the less soluble or more stable forms (CARB, OM, MnOX, AFeOX and CFeOX) to the most soluble form (WE). N natural soils, Ni in the RES fraction was found upto 49%, whereas only 10% of the total Ni was observed in contaminated soil, irrespective of EDTA treatment. In general, the amount of Cd recovered after harvest of both the Brassica cultivars did not differ significantly in any fraction except the WE fraction. The amount of Ni recovered in the AFeOX fraction was significantly higher after harvest of B. juncea as compared to B. carinata.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Population genetic structure of Pinus tabulaeformis in Shanxi Plateau, China

Chinese pine, Pinus tabulaeformis Carr., a species that ranges broadly across northeastern to southwestern China, plays a vital role in the maintenance of the structure and function of these ecosystems. In this study, we examined the genetic diversity of five widespread populations in Shanxi Plateau, the distribution center of Chinese pine, using 15 random amplified polymorphic DNA (RAPD) primers and five inter simple sequence repeat (ISSR) primers in 140 individual tree samples. Similar genetic differentiation results were obtained from the data of RAPD and ISSR. Based on the two sets of data, Nei’s genetic diversity was 0.2842 and 0.3078 and Shannon’s indices of diversity were 0.4332 and 0.4468. Genetic diversity at the species level was found high relative to that for other genera of Pinaceae. The greatest diversity was observed in the Lingkong Mountain population (0.3860), while the lowest was recorded in the Luya Mountain population (0.3352), most likely as a result of natural adaptation and anthropogenic perturbation. The relative magnitude of differentiation among populations (G _ST) was 0.1491 and 0.1356, respectively, implying that most genetic variation was within the populations (∼0.8509), rather than among populations. Published in Russian in Ekologiya, 2008, No. 1, pp. 36–42. The article was translated by the authors.     

Bioaccumulation of Ra by plants growing in fresh water ecosystem around the uranium industry at Jaduguda, India

A field study has been conducted to evaluate the ²²⁶Ra bioaccumulation among aquatic plants growing in the stream/river adjoining the uranium mining and ore-processing complex at Jaduguda, India. Two types of plant group have been investigated namely free floating algal species submerged into water and plants rooted in stream & riverbed. The highest ²²⁶Ra activity concentration (9850 Bq kg⁻¹) was found in filamentous algae growing in the residual water of tailings pond. The concentration ratios of ²²⁶Ra in filamentous algae (activity concentration of ²²⁶Ra in plant Bq kg⁻¹ fresh weight/activity concentration of ²²⁶Ra in water Bq l⁻¹) widely varied i.e. from 1.1 × 10³ to 8.6 × 10⁴. Other aquatic plants were also showing wide variability in the ²²⁶Ra activity concentration. The ln-transformed filamentous algae ²²⁶Ra activity concentration was significantly correlated with that of ln-transformed water concentration (r = 0.89, p < 0.001). There was no correlation between the activity concentrations of ²²⁶Ra in stream/riverbed rooted plants and the substrate. For this group, correlation between ²²⁶Ra activity concentration and Mn, Fe, Cu concentration in plants were statistically significant.     

Biodiversity, food consumption and ecological niche dimension: a study case of the riverine populations from the Rio Negro, Amazonia, Brazil

In this study we perform an ecological analysis of the resources use in the diet of the ribeirinho populations of the Barcelos municipality, Rio Negro, Amazonas, Brazil. Data on food composition, seasonality, and origin took place during three field trips between 1999 and 2000. Data were gathered based on structured interviews and observations from a total of 320 meals of 114 randomly selected families and 164 fishing trips. The staple food of the studied populations is based on fish and manioc, although the food niche amplitude can vary according to the factors such as the access to imported food items, resources seasonality, and socio-economic conditions. The migration to urban centers along with the changes in subsistence activities (reduction of small-scale agriculture and specialization in commercial fishing) may result in changes in the food habits of ribeirinho populations from Rio Negro.

Experience in using ecological phytoindication scales for revealing unfavorable factors at the boundary of species distribution

The ecological phytoindication scales proposed by Tsyganov (1983) were used for characterizing biotopes at the northern limit of the distribution of three nemoral species:Ajuga reptans, Asarum europaeum, andPulmonaria obscura. Regional ecological amplitudes of the model species were determined. The environmental factors approaching the lower limit of species amplitudes in Tsyganov's scales were classified as unfavorable.     

An attempt to recover economic losses from decadal changes in two lagoon systems of Sri Lanka through a newly patented mangrove product

Kahandamodara and Kalametiya are two estuarine lagoons located within about 12 km distance along the Southern coast of Sri Lanka. According to a socio-economic survey, both lagoons have been moderately to high saline water bodies and the latter was an important center of prawn fishery until the late 1960s. Two irrigation projects upstream (Udawalawe irrigation scheme and Muruthawela Wewa), which came into operation in 1967 and 1968 respectively, increased freshwater inflows to these two lagoons and altered flora, fauna, and water quality, with a decline of lagoon fishery as a result. At the same time, the increase in freshwater favorised the Mangrove Apple Sonneratia caseolaris to expand spontaneously. Following many hectares of vegetation increase of this species, our study focused on recovering the economic loss of fisheries decline by using new ethnobotanic information on this species. We found that the pulp of the fruit of the Mangrove Apple is tasty and can be used to prepare a fruit drink. However, it has not been commercialised, or even practiced widely at homes, due to the fact that numerous small seeds in the fruit release certain phenolic compounds when damaged, giving a bad colour and an astringent taste to the pulp. We developed a method to get the fruit pulp from the Mangrove Apple minimising the addition of phenolic compounds. This fruit pulp was then used to produce ice cream and fruit drinks, and the whole procedure has been patented in Sri Lanka for the favour of the local people. Apparently this is a novel mangrove product reported for the first time in mangrove ethnobotany. In addition, analysis of the fruit pulp of the S. caseolaris for nutritional composition revealed that it is very rich in phosphorus and dietary fiber, indicating that these new products may have an even higher potential as a supplementary food. Its use as a health food and as a commercialised eco-product is expected to bring new gains in spite of the former ecosystem and fishery decrease. It is however not known to which extent these novel ethnobiological/socio-economical uses outbalance functions lost by ecosystem degradation.     

Problems of Population Dynamics of the White-Eyed Pochard (Aythya nyrocaGuld., 1770) in the Eastern Sea of Azov Region

The long-term population dynamics of the white-eyed pochard (Aythya nyroca) in the eastern Sea of Azov region was analyzed. It was found that the local population of this species tends to decrease in size. Clutch size, egg size, reproductive behavior, intraspecific clutches, embryonic mortality, and hatching success in this population were studied. The contents of PCDD and PCDF in the eggs of waterfowl were estimated. The eggs of white-eyed pochard, compared to other waterfowl, proved to contain abnormally high concentrations of xenobiotics. Possible causes of A. nyrocapopulation decline, including the impact of superecotoxicants, are discussed.     

Modelling bark beetle disturbances in a large scale forest scenario model to assess climate change impacts and evaluate adaptive management strategies

To study potential consequences of climate-induced changes in the biotic disturbance regime at regional to national scale we integrated a model of Ips typographus (L. Scol. Col.) damages into the large-scale forest scenario model EFISCEN. A two-stage multivariate statistical meta-model was used to upscale stand level damages by bark beetles as simulated in the hybrid forest patch model PICUS v1.41. Comparing EFISCEN simulations including the new bark beetle disturbance module against a 15-year damage time series for Austria showed good agreement at province level (R2 between 0.496 and 0.802). A scenario analysis of climate change impacts on bark beetle-induced damages in Austria’s Norway spruce [Picea abies (L.) Karst.] forests resulted in a strong increase in damages (from 1.33 Mm3 a⁻¹, period 1990–2004, to 4.46 Mm3 a⁻¹, period 2095–2099). Studying two adaptive management strategies (species change) revealed a considerable time-lag between the start of adaptation measures and a decrease in simulated damages by bark beetles.