65 research outputs found

    No increase in fluctuating asymmetry in ground beetles (Carabidae) as urbanisation progresses

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    Environmental stress can lead to a reduction in developmental homeostasis, which could be reflected in increased variability of morphological traits. Fluctuating asymmetry (FA) is one possible manifestation of such a stress, and is often taken as a proxy for individual fitness. To test the usefulness of FA in morphological traits as an indicator of environmental quality, we studied the effect of urbanisation on FA in ground beetles (Carabidae) near a Danish city. First, we performed a critical examina- tion whether morphological character traits suggested in the literature displayed true fluctuating asymmetry in three common predatory ground beetles, Carabus nemoralis, Nebria brevicollis and Pterostichus melanarius. Eight metrical (length of the second and third antennal segments, elytral length, length of the first tarsus segment, length of the first and second tibiae, length of the proximal and distal spines on the first femurs) and one meristic (the number of spines on the second tibiae) traits were examined. Most of them showed FA but not consistently. Females generally displayed a higher level of FA than males. Finally, we examined the changes in the level of FA in bilateral morphological traits along an urbanisation gradient (forest - suburban forest - forest fragments in urban park) to test whether environmental stress created by urbanisation is reflected in FA. Ground beetles common along a Danish urbanisation gradient did not seem to indicate differences in habitat quality by their level of F

    Transgenic Insecticidal Crops and Natural Enemies: A Detailed Review of Laboratory Studies

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    This review uses a data-driven, quantitative method to summarize the published, peer-reviewed literature about the impact of genetically modified (GM) plants on arthropod natural enemies in laboratory experiments. The method is similar to meta-analysis, and, in contrast to a simple author-vote counting method used by several earlier reviews, gives an objective, data-driven summary of existing knowledge about these effects. Significantly more non-neutral responses were observed than expected at random in 75% of the comparisons of natural enemy groups and response classes. These observations indicate that Cry toxins and proteinase inhibitors often have non-neutral effects on natural enemies. This synthesis identifies a continued bias toward studies on a few predator species, especially the green lacewing, Chrysoperla carnea Stephens, which may be more sensitive to GM insecticidal plants (16.8% of the quantified parameter responses were significantly negative) than predators in general (10.9% significantly negative effects without C. carnea). Parasitoids were more susceptible than predators to the effects of both Cry toxins and proteinase inhibitors, with fewer positive effects (18.0%, significant and nonsignificant positive effects combined) than negative ones (66.1%, significant and nonsignificant negative effects combined). GM plants can have a positive effect on natural enemies (4.8% of responses were significantly positive), although significant negative (21.2%) effects were more common. Although there are data on 48 natural enemy species, the database is still far from adequate to predict the effect of a Bt toxin or proteinase inhibitor on natural enemies

    Cry Toxins and Proteinase Inhibitors in Transgenic Plants do have Non-Zero Effects on Natural Enemies in the Laboratory: Rebuttal to Shelton et al. 2009

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    A main point of our recent paper (Lovei et al. 2009) is that there are non-neutral effects of Cry toxins and proteinase inhibitors (PIs) on natural enemies in the laboratory and that the pattern of responses is complex and needs additional analysis. Shelton et al. (2009) aggressively attacked this conclusion. They claimed that all negative effects of Cry toxins are caused by effects of sublethally affected hosts and prey. We suggested in Lovei et al. (2009) and reiterate here that the actual situation is not that simple when laboratory studies are considered. We made our point by using statistical meta-analysis to show that there are more nonzero effects of Cry toxins and PIs on natural enemies than expected under a statistical null hypothesis that all observed effects were zero. The interested reader may want to examine the longer history of some of these issues (Lovei and Arpaia 2005; Andow et al. 2006; Romeis et al. 2006a,b). In our rebuttal, we first address the deeper, fundamental questions raised by Shelton et al. (2009) about the value of meta-analysis and then proceed to rebut the core criticisms about our statistical methods. Although Shelton et al. (2009) raised many other issues, we limited our rebuttal to these central issues; our lack of comment does not imply agreement with their other complaints. Shelton et al. (2009) make two criticisms of our work that are, in actuality, more fundamental criticisms of meta-analysis. These criticisms are made, in part, to defend the methods used and conclusions reached in reviews by O'Callaghan et al. (2005) and Romeis et al. (2006b), neither of which are based on meta-analyses. First they argued that nonsignificant P values are "devoid of futher meaning and interpretation" (Shelton et al. 2009, p. 318), and second, they

    Developing an integrated land use planning system on reclaimed wetlands of the Hungarian Plain using economic valuation of ecosystem services

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    The establishment of a sustainable land use system is crucial in Hungary (SE Europe) where 30% of croplands lie on former floodplains, and 40–45% of arable lands are drought-prone. We calculated and compared the monetary value of the main wetland ecosystem services, the profitability of land use and the additional costs of grain producer system on land at risk from groundwater inundation on the Hungarian Plain. We show that orchards and forestry generate a much higher profitability in former wetlands than cropland farming. Using the replacement cost method, we prove that the reservoir capacity of restored wetlands with an ecologically optimal 0.5 m water depth could replace 2150 €ha−1 flood protection investment cost. The calculated costs of protecting land under the two highest groundwater risk categories between 1999–2005 was 37.2 €ha−1 y−1 and 14.9 €ha−1 y−1, respectively. Although the flood protection benefits of former wetlands may provide an appropriate value base for restoration per se, combined with the potential advantages of land use change from cropland to forest in former wetlands and the carbon sequestration benefit provide ‘win-win’ solutions for land users and institutional actors interested in flood prevention, environmental protection and climate mitigation

    Ászkarák (Crustacea, Isopoda) együttesek egyedszám változásai egy dániai urbanizációs grádiens mentén

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    Szárazföldi ászkarák együtteseket (Isopoda: Oniscidea) tanulmányoztunk egy urbanizációs grádiens mentén 2004-ben a dániai Sorø mellett, a Globenet-protokoll szerint. Jelen tanulmányunkban négy mintavételi periódust értékeltünk. Három hipotézist vizsgáltunk: (a) a fajdiverzitás a zavarás növekvő mértékével csökken; (b) a fajdiverzitás a közepesen zavart területen a legnagyobb; (c) a zavartabb területeken megjelennek kozmopolita és/vagy behurcolt fajok. A természetes – városszéli és városi élőhelyek fajösszetétele megegyezett: Porcellio scaber, Oniscus asellus, Philoscia muscorum, Armadillidium vulgare, Trachelipus rathkii, Ligidium hypnorum. Az urbanizáció hatása nem a fajok minőségi összetételében, hanem azok egyedszám eltéréseiben tükröződött. Az egyes fajok élőhelytípusonkénti gyakorisága – a P. muscorum kivételével – szignifikánsan különbözött egymástól
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