The structure of absorbing roots in invasive and native maple species

Specific structural features of absorbing roots have been studied in Acer negundo (an invasive species in the southern Cisural region), compared to native Acer platanoides and A. tataricum. A comparative analysis of the diameter of fine roots, stele and bark volumes, and the frequencies of roots with retained primary bark, root hairs, arbuscular mycorrhiza, and dark septate endophytes has been performed in the invasive and native species from four habitats (by two habitats in the forest–steppe and steppe zones). The roots of A. negundo have been additionally studied in trees from two monospecific stands. It has been found that the structure of fine roots significantly differs between the invasive and native species: the roots of A. negundo are larger, with relatively poorly developed root hairs and low occurrence of dark septate endophytes. In monospecific stands, the frequency of mycorrhiza in A. negundo roots is very low, with arbuscules and dark septate endophytes being totally absent. It is concluded that specific structural features of the belowground absorbing apparatus in A. negundo are accounted for mainly by traits autonomously formed in a plant, rather than by characteristics of symbiotic relationships, and that they are not consistent with the assumption that the invasive species can utilize soil resources more effectively or more rapidly than taxonomically close native species.     

Implications of future bioclimatic shifts on Portuguese forests

As climate is an important driver of vegetation distribution, climate change represents an important challenge to forestry. We (1) identify prevailing bioclimatic conditions for 49 relevant forest species in Portugal and (2) assess future shifts under climate change scenarios. We compute two bioclimatic indices (aridity and thermicity) and a new composite index, at ~1 km spatial resolution, and overlap with the species’ current ranges. Locations are based on a digital inventory, while climate parameters for both recent-past (1950–2000) and future climates (2041–2060), under RCP4.5 and RCP8.5, are provided by a multi-model ensemble of climate simulations. Results for future scenarios highlight an overall warming and drying trend. Supramediterranean and mesomediterranean climates will be significantly reduced, while thermomediterranean climates will dramatically increase, from their almost absence in current conditions to an area coverage of ~54 % in 2041–2060 for RCP8.5. There is also a clear shift from hyper-humid and humid to sub-humid and from the latter to semi-arid climates (area coverage of ~13 % in 2041–2060 for RCP8.5). Lower thermomediterranean sub-humid to semi-arid zones will cover the southern half of Portugal. These projections identify the most vulnerable (e.g. Betula pubescens, Quercus pyrenaica and Castanea sativa) and the most adapted (e.g. Quercus suber, Q. rotundifolia, Ceratonia siliqua, Pinus pinea, Quercus coccifera) species in future climates. Current bioclimatic zones associated with Eucalyptus globulus and Pinus pinaster, economically relevant species, will be moderately reduced and relocated. Possible adaptation measures are discussed to improve forest resilience to climate change, while maintaining its economic and environmental benefits.     

Livestock foraging behaviour on different land use classes along the semi-arid to sub-humid agro-ecological gradient in West Africa

This study compared the use of different land use classes and major foraging activities of pastoral and agro-pastoral livestock in the southern Sahelian, northern and southern Sudanian zone of Burkina Faso by monitoring three herds each of cattle, goats and sheep in three village territories during a 1-year cycle. Grazing routes were tracked using a Global Positioning System; coordinates logged every 10 s were overlaid on maps from where time and activity allocated to different land use classes were derived. Results indicate that daily distance travelled by cattle and goat herds was similar across agro-ecological zones (AEZs; p ≥ 0.05), whereas sheep travelled shorter distances in the southern Sudanian zone than in the two more northern zones (p ≤ 0.05). Daily pasturing time of cattle and sheep was longer (p ≤ 0.05) in the southern Sahelian and northern Sudanian zone than in the southern Sudanian zone. For goats, no significant difference was found between the two Sudanian zones, where their pasturing time was shorter than in the southern Sahelian zone. Except resting for cattle, browsing for goats and walking for sheep, time spent on different foraging activities by each species was similar across AEZs. Main areas for feeding across AEZs and species were degraded lands, fallows and harvested crop fields, as well as shrub and tree savannahs in the two Sudanian zones. To safeguard the nutrition of grazing livestock herds, interventions should focus on conserving still-existing pasture lands and regional livestock migration corridors to enable use of the remaining, often highly dispersed, pasture resources.     

Residues of organochlorine pesticides in fish from the Egyptian delta lakes

The distribution and residue levels of BHC, Lindane, Endrin, o,p′-DDT, p,p′-DDE, and p,p′-DDD in Mugil and Tilapia species collected from Egyptian Delta lakes were evaluated. Residues of BHC and p,p′-DDT were found in most fish samples obtained from El-Manzala, El-Burullus, Edku, and Maryut lakes. Fish samples from Lake Edku showed the highest residue levels of the studied compounds. Residues of BHC and p,p′-DDT in Mugil and Tilapia species are within the range found in fish from the northwest Atlantic but lower than the levels reported for other fish species the United States. Mugil and Tilapia species could be used as indicator organisms for monitoring the residue levels of organochlorine pesticides and their distribution.     

Spatial analysis of soil resources in the Mewat district in the semiarid regions of Haryana,India

The soil characteristics are critical for crop health and its yield and therefore for agriculture. The soil properties are spatially variable and therefore soil resources should be managed as per location-specific requirements. An integrated spatial analysis of the soil resources of Mewat district was conducted to identify the soil resource management zones to develop site-specific soil management plan which might lead to sustained and enhanced crop yield. Spatial analysis of soil resources was conducted by modeling soil fertility and erosion which determines the crop productivity in the region. Soil fertility of the region was modeled using weighted overlay approach using 10 soil parameters, namely nitrogen, phosphorus, potassium, sulfur, iron, zinc, manganese, organic carbon, electrical conductivity, and pH. Each parameter was assigned weights based on their relative importance to agricultural productivity. The modeled soil fertility was classified into three fertility zones, low, medium, and high. Soil fertility was found to be low to moderate in 65% of the area, largely because of the low nitrogen, soil organic carbon, phosphorus concentration, and excessive salinity. Soil erosion was modeled using the universal soil loss equation (USLE) model by estimating rainfall erosivity factor (R), the soil erodibility factor (K), the topographic factors (L and S), cropping factor (C), and the conservation practice factor (P). Soil erosion problems were limited to areas having high elevation with barren land and areas with minimal management practices. The severity of soil erosion was found high in 15% of the region, while the remaining 85% showed low to moderate erosion. Soil fertility and erosion were integrated using the multivariate clustering method to identify soil management zones. The region was delineated into three soil management zones. Zone I (29%) which covers majorly Tarou block, was characterized by high soil fertility and low soil erosion. Zone II (18%) with medium soil fertility and high erosion covers villages of Taoru, Nuh, Nagina, FP Jhirka, and Punhana, which are located in the foothills of Aravalli ranges. Zone III represents the major part of the region, covering Nuh, Nagina, and FP Jhirka blocks (54%) with low soil fertility and erosion conditions. Thus, within the study area, the soil management domains are spatially variable in terms of fertility and soil erosion, and thus zone-specific soil management measures are required to improve the soil condition in order to sustain and improve agriculture production. The study would help the policy makers to design site-specific planning for identified soil resource management zones.     

Plant communities in the zone of gas field development and heavy metal accumulation by them

Heavy metal accumulation by plant communities has been studied in different zones of impact of gas field development. The contents of heavy metals in different blocks of plant communities has proved to depend not only on the location of phytocenosis but also on its species composition. Communities dominated by species of the family Poaceae contain smaller amounts of heavy metals than those dominated by species of the family Asteraceae, especially of the genus Artemisia. The order of precedence in the accumulation of heavy metals in different blocks of plant communities has been revealed.     

Characteristics of parasitic infection in the least cisco, Coregonus sardinella valenciennes, 1848, in the Ural tributaries of the lower Ob

Data on the parasite fauna of the least cisco, Coregonus sardinella Valenciennes, 1848 in Ural tributaries of the Ob downstream of the city of Salekhard have been obtained for the first time. The formation patterns of the parasite fauna in this species and the rate (prevalence and intensity) of infection by Ichthyocotylurus erraticus (Odening, 1969), a parasite specific to coregonids, have been revealed. Infection of the least cisco with six parasite species (out of the 12 species found) occurs as the fish feed on zooplankton and benthic organisms. The dominant parasites are trematode larvae of the genera Ichthyocotylurus and, in some years, Diplostomum; this composition of dominants is evidence that the least cisco fattens up mainly in shallow areas. All sexually mature fish of this species were found to be infected by I. erraticus, but the average intensity of infection was rather low: the abundance index of the parasite did not exceed 40 ind. per fish. Analysis of the distribution of I. erraticus metacercariae in the least cisco shows that the relationship in the host-parasite system is stable and the parasite has no pathogenic effect on individuals of older age classes.     

Palm use and social values in rural communities on the coastal plains of Veracruz, Mexico

Palms are a resource of great importance in the tropics and are found in a variety of ecosystems, including the wetlands of the tropical coastal plains. In order to recover wetland ecosystems, we studied the traditional uses of wetland palms, by conducting interviews in the communities of four municipalities on the Gulf of Mexico coast. We found that people use five species of palm: Cocos nucifera, Sabal mexicana, Attalea liebmannii, Roystonea dunlapiana and Acrocomia aculeata. Main uses for the five species were for food and construction materials. Although palms are still used, traditional knowledge is declining in the younger generations, likely as a result of various social, cultural and economic factors. It is important to recover and promote the traditional use and value of palm trees, especially for the native species, because of both the economic benefits and the environmental services they provide. More participatory work with the inhabitants is needed to initiate palm breeding programs to assist in the recovery of wetland ecosystems.     

Sediment integrative assessment of the Bay of Cádiz (Spain): An ecotoxicological and chemical approach

This study consisted of the sediment toxicity assessment of the Bay of Cádiz based on two endpoints: growth inhibition for Cylindrotheca closterium (benthic microalgae) and fecundity inhibition for Tisbe battagliai (harpacticoid copepod). A new methodology to eliminate (but not as storage technique) the autochthonous biota present in the sediment samples by immersing them in liquid nitrogen (? 196 °C) was also assessed. Sediment toxicity data showed different toxicity levels for both organisms. In general, T. battagliai was more sensitive; however a good correlation (r = 0.75; p  < 0.05) between sediment toxicity results for both species was found. Data in pore water (pH, redox potential, and toxicity for microalgae and copepod) and sediment (pH, redox potential, organic carbon, and metal concentrations) demonstrated that ultra-freezing did not alter sample characteristics; thus, this technique can be adopted as a pre-treatment in whole-sediment toxicity tests in order to avoid misleading results due to presence of autochthonous biota. Multivariate statistical analysis such as cluster and principal component analysis using chemical and ecotoxicological data were employed. Silt and organic matter percentage and lead concentration were found to be the factors that explain about 77% of sediment toxicity in the Bay of Cádiz. Assay methodology determined in this study for both assayed species is considered adequate to be used in sediment toxicity monitoring programs. Results obtained using both species show that the Bay of Cádiz can be considered a moderately polluted zone.     

Ecological and faunistic characteristics of the leech fauna in the Bukhtarma Reservoir,Eastern Kazakhstan

The taxonomic diversity of the Hirudinea fauna and its dependence on the ecological conditions in the Bukhtarma Reservoir (Eastern Kazakhstan) have been studied. The morphological analysis has shown that these leeches belong to two orders and three families: Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and Arhynchobdellida (family Erpobdellidae). On the whole, eight leech species from five genera (Alboglossiphonia, Helobdella, Theromyzon, Piscicola, and Erpobdella) have been identified. Among them, there are three glossiphoniid species (A. heteroclite, H. stagnalis, and T. tessulatum), two species of piscicolids (Piscicola geometra and Piscicola sp.), and three species of predatory leeches (E. octoculata, E. vilnensis, and Erpobdella sp.). Possible effects of hydrochemical parameters of the aquatic environment on the species diversity have been analyzed. Correlation has been revealed between the abundance of species and the physical and chemical characteristics of the environment.     

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.     

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.     

Ecological preferences of forest voles

Basic climatic parameters (annual average air temperature and annual amount of precipitation) over 12–25 years have been analyzed with regard to their values corresponding to different levels of abundance in three species of forest voles: Clethrionomys glareolus (in 11 areas of the species range), Cl. rutilus, and Cl. rufocanus (in three areas each). The results show that the abundance of all these species correlates significantly with fluctuations of annual average temperature, with the correlation being negative in Cl. glareolus and Cl. rufocanus but positive in Cl. rutilus. In addition, the abundance of Cl. rufocanus shows a significant correlation with annual precipitation. Voles inhabiting different geographic regions may reach high abundance under different conditions. As for the species range as a whole, however, Cl. glareolus is more ecologically flexible than the other two voles. This species is also more warmth- and moisture-loving, while Cl. rufocanus is more cold-loving and xerophilous, with Cl. rutilus occupying an intermediate position between them. Clethrionomys rutilus is most temperature-dependent and stenothermic among them, whereas Cl. glareolus is indifferent to the factors studied.     

Mercury in twelve Mediterranean trawl fishes of Israel

Total mercury concentration was investigated in the edible portion (muscle tissue) of twelve commercial trawl fishes. Samples were collected by a commercial trawl from five stations along the Mediterranean coast of Israel at depths from 32.9 – 91.4 m.The range and average mercury concentrations for both individual and composite samples of ten species are tabulated. The range of total lengths and weights for each species is also given. For two species only one composite sample was obtained.Sufficient data were obtained for five species to discuss the variation of mercury concentration with length, with depth and by station. Mercury concentration was found to increase with length for Saurida undosquamis, Trachurus mediterraneus, Upeneus moluccensis and Pagellus erythrinus. The correlation between mercury concentration and total length in Mullus barbatus was low. The mercury concentration of this species appeared to increase with depth. Mercury concentration in the fishes examined is discussed in regard to their position in the food web, depths and distribution along the shore.     

Sex-specific predation on two lizard species by kestrels

Sex-biased predation is thought to have important implications for sexual selection, sex allocation, and population dynamics (Magnhagen, 1991; Le-Galliard et al., 2005 for an example in lizards). Most studies found that males are subjected to higher predation pressure than females during the reproductive season (Korpimäki, 1985; Lodé et al., 2004; Christe et al., 2006; Costantini et al., 2007). In that period, males are very mobile, emit acoustic signals and exhibit brilliant colourations, which are needed to attract females but may make them more visible to predators. With regard to lizards, a recent study provided the first evidence that males of a lizard species may be preyed on more than females (Costantini et al., 2007). In the present study, we investigated whether there is sex-biased predation on two small lacertid species, the common wall lizard Podarcis muralis (Laurenti, 1768) and the Italian wall lizard Podarcis sicula (Rafinesque-Schmaltz, 1810), by Eurasian kestrels (Falco tinnunculus) during the reproductive season. We also examined whether (1) the rate of predation differed between species and (2) the rate of predation differed across years or among hunting habitats for each species.     

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.     

Phenotypic variation of Gymnadenia conopsea (L.) R. Br. (Orchidaceae) in marginal populations on limestones in the northeast of European Russia

Individual, intra- and interpopulation, ecological, and geographic variation has been studied in G. conopsea populations on limestones of the Timan Range. The results show that the response of plants to deterioration of growing conditions manifests itself in a decrease in the values of individual morphometric characters and the strength of correlations between them. In the northeast of European Russia, this species is represented by two forms, G. conopsea (L.) R.Br. s. str. and G. conopsea var. alpina Rchb. f. ex Beck (?), with the latter being regarded as an extreme form of its ecological variation.     

Influence of macroalgal diversity on accumulation of radionuclides and heavy metals in Bulgarian Black Sea ecosystems

Radionuclides and heavy metals were studied in green, brown and red Black Sea macroalgae by low-level gamma spectrometry and atomic absorption spectrometry. The samples were collected along the whole Bulgarian coast from 1996 to 2004. The levels have been depending on algae species, locations and year of sampling. The highest ¹³⁷Cs levels were found in red Ceramium rubrum species from all studied locations, while ²²⁶Ra and ²¹⁰Pb were up to three orders of magnitude higher in Bryopsis plumosa. The data showed that the red algae species (Rhodophyta) accumulate more heavy metals than the other phyla (except for Fe whose values were higher in green algae). The data confirmed that algae are valuable indicators of the environmental contamination. The observed elevated levels were mainly due to Danube, Dnieper and Dnester inputs in the NW corner of the Black Sea.     

Effects of landforms on the erosion rate in a small watershed by the Cs tracing method

It's very important to analyze and evaluate quantitatively the effects of landforms on soil erosion for the prevention and treatment of soil loss in a small watershed. The objective of this study was to evaluate the effects of landform factors on erosion rate by the ¹³⁷Cs tracing method in a small watershed in the Purple Hilly Area of China. The erosion rates under different slope lengths, slope gradients and slope aspects were estimated in Xiangshuitan watershed in the Purple Hilly Area in Sichuan Basin by the ¹³⁷Cs tracing method. The results showed that the erosion rate decreased exponentially with downslope distance, and it increased with increasing slope gradient during the scope of 5°-16°. The slope aspect had great impact on the erosion rate, and the hillside on the sunny slope had larger erosion rate than that on the shady slope, particularly for the farmland.     

Morphological relationships of the Wheatears (genus Oenanthe)

The genus Oenanthe comprises approximately 22 species, of which 16 species are restricted to the desert belt of the Palaearctic and Afrotropic regions, where they are often the most conspicuous passerines. Although they have been the subjects of some morphological and ecological studies, no complete morphometrical data has been used to verify their taxonomic relationships, and, the species relationships are still debated. Overall morphometrical similarities between Wheatears and their relationships in size and shape were assessed using measurements of 27 biometrical variables on 417 museum specimens. The 22 Wheatear species comprise some morphological groups: long migratory vegetation-tolerant species (O. pleschanka, O. hispanica, O. cypriaca and O. deserti), ground-dwelling migratory (O. isabellina and O. oenanthe), and sedentary (O. bottae, O. heuglini and O. pileata) of steppe-like habitants, relatively heavy and rock-dwelling species (O. leucura and O. monticola), inhabiting the most arid areas (O. monacha, O. leucopyga and O. alboniger), and finally a central core of medium-sized partial migrants, largely overlapping in morphometric space, that do not present any evident specialization (O. lugens, O. chrysopygia, O. xanthoprymna and O. finschii). It seems Wheatear species are well distributed in a morpho-space of size and shape with moderate overlaps and few hiatuses corresponding to a morphological continuum of species. Furthermore, our results largely hiatuses corresponding to a morphological continuum of species. Furthermore, our results largely differ from previous phylogenetic hypotheses (based on ecological, behavioural, and chromatic characters), but, are in congruence with molecular data.