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Chilka Saha, Saida Parveen, Joy Chakraborty, Soujita Pramanik and Gautam Aditya

Abstract

The life table characteristics of the invasive snail Physa acuta were assessed in the laboratory using the individuals occurring in a newly colonised area in Burdwan, West Bengal, India. Using the changes in the shell length and the body weight of the snails as surrogate, the population growth of the snails was estimated along with longevity and the fecundity schedule. The cohort of P. acuta lived for a maximum of 22 weeks with a life expectancy (ex) of 7.27 weeks and the age-specific survivorship being 0.825. Increment of the shell length of the snails complied with the von Bertalanffy growth equation, lt = 11.75(1 − exp−0.17(t−0.06)), and the observed and the expected data of the length at time t (lt) did not vary significantly (z score = 0.230; P = 0.818; n=20 pairs). Following attainment of sexual maturity between 28 and 42 days, oviposition continued till 20 weeks time, with 0.1-10 eggs laid by each individual. The eggs present per capsule remained between 01 and 11, whilst the net reproductive rate (R0), intrinsic rate of increase (rm) and the finite rate of increase (λ) were 116.07, 0.1 and 1.11, respectively. The observations are similar to those made earlier on the same species but from African and South American continents. The results of the present observation are pioneer in providing the initial studies about the life history of the invasive snail P. acuta in Indian context. Using the present information as a basis, further studies including long-term population monitoring should be initiated to understand the effects of the invasive snail P. acuta in the freshwater ecosystem of West Bengal, India.

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Peter Hanajík, Milan Zvarík, Hannu Fritze, Ivan Šimkovic and Róbert Kanka

Abstract

We studied soil PLFAs composition and specific soil properties among transect of small-scale fen in Stankovany, Slovakia. The aim of this study was to determine potential differences in the microbial community structure of the fen transect and reveal correlations among PLFAs and specific soil characteristics. PCA analyses of 43 PLFAs showed a separation of the samples along the axis largely influenced by i14:0, 16:1ω5, br17:0, 10Me16:0, cy17:0, cy17:1, br18:0 and 10Me17:0. We measured a high correlation of sample scores and distance from fen edge (Kendall’s test τ = 0.857, P < 0.01). Kendall’s test showed a negative correlation of PLFAs content (mol%) and distance from the fen border for Gram (+) bacteria, Actinomycetes, mid-chain branched saturated PLFAs and total PLFAs. The redundancy analysis of the PLFA data set for the eight samples using PLFAs as species and 21 environmental variables identified soil properties significantly associated with the PLFA variables, as tested by Monte Carlo permutation showing most significant environmental variables including dichlormethan extractables, water extractables, Klason lignin, acid-soluble lignin, holocellulose, total extractables, organic matter content, total PLFA amount, bacterial PLFA and total nitrogen negatively correlated to axis 1 and dry weight and carbonate carbon positively correlated to axis 1. The amounts of Klason lignin, acid-soluble lignin, holocellulose total extractables, total PLFA, bacterial PLFA and total nitrogen were significantly correlated positively to the distance from fen border while moisture and total carbonate carbon were correlated negatively.

Open access

Peter Bezák and Magdaléna Bezáková

Abstract

Landscape represents appropriate spatial dimension for a study of ecosystems, especially due to ability to translate scientific knowledge into proper guidance for land use practice and enhancing the inclusion of local stakeholders in decision-making procedures. We tested social preferences method to reach initial and raw overview of the ecosystem services (ES) distribution and their values in the study areas. Perception of experts and local residents about capacities of relevant CORINE land cover (CLC) types to provide various ES was linked with Geographic Information System databases. We quantified the results on the basis of the mean values for each CLC type and the ES groups and these were interpreted also in spatial context. The expectation about perceptible capacities of forest to provide goods and services was fulfilled by responses of the experts, as was the expected difficulty to assess capacities of transitional woodland shrub or complex cultivation patterns. However, additional land cover types in question are meadows and pastures or discon-tinuous urban fabric. Mostly middle ranking values prevail in responses of local residents and uncertainty in the background is much greater comparing to the experts. On the other hand, rural people may better recognise diversified fow of services due to their everyday close connection to more ES. Large variation in the scores of some valued CLC classes in responses of the local residents and also experts seems resulting from lack of knowledge in the background and differences in viewpoint and appreciation. We understand the gaps in evaluating ES by the experts and resident population as good experience and key challenge for the further steps and fine-tuning of the research methods.

Open access

Dominika Dąbrowska and Jan Dąbrowski

rates of North American freshwater fauna. Conserv. Biol., 13: 1220-1222. Rosset V., Simaika J.P., Arthaud F., Bornette G., Vallad D., Samways M.J., Oertli B. 2013. Comparative assessment of scoring methods to evaluate the conservation value of pond and small lake biodiversity. Aquatic Conser. Mar. Fresh. Ecosyst ., 23: 23-36. Rzętała M. 2008. Funkcjonowanie zbiorników wodnych oraz przebieg procesów limnicznych w warunkach zróżnicowanej antropopresji na przykładzie region śląskiego. Uniw. Śląski, Katowice. Rzętała M., Rahmonov O., Malik I., Oleś

Open access

Pawel Wasowicz

conceptual framework for prioritization of invasive alien species for management according to their impact. NeoBiota , 15: 69-100. Kumschick S., Bacher S., Evans T., Markova Z., Pergl J, Pysek P., Vaes-Petignat S., van der Veer G., Vila M., Nentwig W. 2015. Comparing impacts of alien plants and animals in Europe using a standard scoring system. J. Appl. Ecol ., (in press) DOI: 10.1111/1365-2664.12427. Kumschick S., Richardson D.M. 2013. Species-based risk assessments for biological invasions: Advances and challenges. Divers. Distrib ., 19: 1095

Open access

Florian Ahlmeyer and Dirk Wittowsky

2004 ; Wulfhorst/Büttner/Ji 2017 ). Nachfolgend werden die methodentheoretischen Grundlagen vorgestellt, die der Entwicklung des neuen Erreichbarkeitsindexes zugrunde liegen. Modelle für kombinierte Erreichbarkeitsindizes (z. B. Walk Score, walkability ) werden vornehmlich für die fußläufige Erreichbarkeit aufgebaut (vgl. Frank/Sallis/Saelens et al. 2010 ; Walk Score 2011 ; Dinkel 2014 ). Generell bezieht sich die Erreichbarkeitsdebatte vor allem auf städtische Räume ( Rode 2014 ). Erreichbarkeitsindizes können aber gerade in ländlichen Räumen als

Open access

Michael Hoyler

other sources (e.g. annual reports of firms). In order to enable comparison across firms, the available information for every firm was standardized for each of its office locations to categorize their importance in a firm’s office network. Service values v ij were allocated on a scale from 0 (no presence of a firm in a city) to 5 (global headquarters of a firm in a city). The criteria applied to assess and score offices relate primarily to office size and extra-locational functions of the office(s). For example, all cities where a firm was present initially scored 2

Open access

Jiří Hasman, Yvona Kostelecká and David Hána

References: ALBA, R., NEE, V. (2005): Remaking the American mainstream: assimilation and contemporary immigration. Cambridge, Harvard University Press. BIFULCO, R., LADD, H. F. (2007): School choice, racial segregation, and test-score gaps: Evidence from North Carolina's charter school program. Journal of Policy Analysis and Management, 26: 31–56. BIFULCO, R., LADD, H. F., ROSS, S. L. (2009): Public school choice and integration evidence from Durham, North Carolina. Social Science Research, 38(1): 71–85. BLACK, S. E. (1999): Do Better

Open access

Aneta Spyra

., 74, 125−133. DOI: 10.1016/0006-3207(95)00021-U. Fehér, Z., Majoros, G. & Varga A. (2004). A scoring method for the assessment and conservation value of the Hungarian freshwater mollusc. Heldia, 6, 1−14. Gibbs, J.P. (1993). Importance of small wetlands for the persistence of local populations of wetland-associated animals. Wetlands, 13, 25−31. DOI: 10.1007/BF03160863. Glöer, P. & Meier- Brook C. (1998). Susswassermollusken. 12 Auf. Hamburg: DJN. Glöer, P. (2002). Suswassergastropoden Nord- und

Open access

Jonathan V. Beaverstock

1 Introduction Over the last decade, there has been a renaissance in the study of the connectivities and polycentricity of European cities in an age of economic prosperity and accelerating globalization ( Hall/Pain 2006 ; Taylor/Ni/Derudder et al. 2011 ). In these extant studies as well as in others (for example Hoyler/Freytag/Mager 2008 ; Derudder/Taylor/Ni et al. 2010 ), German cities, especially those associated with the Rhine hinterland, Ruhr and Main, have displayed relatively mediocre connectivity scores in relation to other European and global