Search results for "conte"
showing 10 items of 10369 documents
Exploration of the Oxynoticeratidae ornamental morphospace using the discrete cosine transform (DCT) to analyze rib patterns.
2006
The discrete cosine transform (DCT) is a Fourier-related transform widely used in signal processing and well suited to analyzing open outlines such as ammonite ribs. The method is applied here to depict and decipher the ribbing morphospace of a large group of Lower Jurassic ammonites composed of the Oxynoticeratidae and their close ancestors. Because they are clearly associated with buoyancy and/or swimming ability, the usually clearly involute, comparatively smooth and compressed shells of these ammonites may well be misleading taxonomic markers. In this context, quantitative analysis of the ribbing pattern using the DCT may significantly improve our perception of the ornamental patterns e…
Determination of fatty acids content, global antioxidant activity and energy value of weed seeds from agricultural fields in France.
2016
18 pages; International audience; The ecological consequences of seed size variation have been studied extensively in plants. Curiously, little attention has been paid to the qualitative and quantitative variation of the seed-stored molecules and on their ecological significance. Here, we analysed the oil content and oil composition of ca. 200 weed seed species from agricultural fields in France based on single seed accessions, concentrating on interspecies differences and ignoring within-species variation. The relationships between seed weight, oil %, fatty acids (FAs) and the energetic value of the seed and its antioxidant properties were also investigated. The antioxidant activity could …
Land cover and its transformation in the backward trajectory footprint region of the Amazon Tall Tower Observatory
2019
Abstract. The Amazon rain forest experiences the combined pressures from human-made deforestation and progressing climate change, causing severe and potentially disruptive perturbations of the ecosystem's integrity and stability. To intensify research on critical aspects of Amazonian biosphere–atmosphere exchange, the Amazon Tall Tower Observatory (ATTO) has been established in the central Amazon Basin. Here we present a multi-year analysis of backward trajectories to derive an effective footprint region of the observatory, which spans large parts of the particularly vulnerable eastern basin. Further, we characterize geospatial properties of the footprint regions, such as climatic condition…
A 350 year drought reconstruction from Alpine tree ring stable isotopes
2010
[1] Climate reconstructions based on stable isotopes in tree rings rely on the assumption that fractionation-controlling processes are strongly linked to meteorological variables. In this context, we investigated the climate sensitivity of 350 years of carbon and oxygen isotope ratios of tree ring cellulose from European larch obtained at a high-elevation site in the Swiss Alps (∼2100 m above sea level). Unlike tree ring width and maximum latewood density, which contain only summer temperature information at this site, we found that our stable isotope series reveal additionally to temperature a striking sensitivity to precipitation (mainly for carbon) and sunshine duration (mainly for oxyge…
Fifteen operationally important decisions in the planning of biodiversity offsets
2018
Many development projects, whether they are about construction of factories, mines, roads, railways, new suburbs, shopping malls, or even individual houses, have negative environmental consequences. Biodiversity offsetting is about compensating that damage, typically via habitat restoration, land management, or by establishment of new protected areas. Offsets are the fourth step of the so-called mitigation hierarchy, in which ecological damage is first avoided, minimized second, and third restored locally. Whatever residual damage remains is then offset. Offsetting has been increasingly adopted all around the world, but simultaneously serious concerns are expressed about the validity of the…
Response and effect traits of arable weeds in agro-ecosystems: a review of current knowledge.
2017
25 pages; International audience; Integrating principles of ecological intensification into weed management strategies requires an understanding of the many relationships among weeds, crops and other organisms of agro-ecosystems in a changing context. Extensively used during the last two decades in weed science, trait-based approaches have provided general insights into weed community response to agricultural practices, and recently to understanding the effect of weeds on agro-ecosystem functioning. In this review, we provide a holistic synthesis of the current knowledge on weed response and effect functional traits. Based on the literature and recent advances in weed science, we review cur…
Sex ratio at mating does not modulate age fitness effects in Drosophila melanogaster
2019
Abstract Understanding the effects of male and female age on reproductive success is vital to explain the evolution of life history traits and sex‐specific aging. A general prediction is that pre‐/postmeiotic aging processes will lead to a decline in the pre‐ and postcopulatory abilities of both males and females. However, in as much the sexes have different strategies to optimize their fitness, the decline of reproductive success late in life can be modulated by social context, such as sex ratio, in a sex‐specific manner. In this study, we used Drosophila melanogaster to investigate whether sex ratio at mating modulates age effects on male and female reproductive success. As expected, male…
Leaf sodium, potassium and electrolyte accumulation capacity of plant species from salt-affected coastal habitats of the Baltic Sea: Towards a defini…
2021
Abstract The aim of the present study was to compare a relatively large number of native plant species from salt-affected coastal habitats with respect to their Na+ and K+ accumulation capacity and electrolyte level in leaves. Sampling sites (77 in total) were chosen during field survey in coastal habitats located at geographically distant places along the Baltic Sea in the territory of Latvia, Estonia, Denmark and Sweden. The main criterion for selection of sampling sites was minimum average soil electrical conductivity (EC) above 200 mS m–1. Leaf samples of 102 taxa (species) from 34 families were collected, with a total number of samples reaching 502, and their water content, Na+ and K+ …
Ectomycorrhizal fungi in wood-pastures : Communities are determined by trees and soil properties, not by grazing
2019
Traditional rural biotopes such as wood-pastures are species-rich environments that have been created by low-intensity agriculture. Their amount has decreased dramatically during the 20th century in whole Europe due to the intensification of agriculture. Wood-pastures host some fungal species that prefer warm areas and are adapted to semi-open conditions, but still very little is known about fungi in these habitats. We studied how management, historical land-use intensity, present grazing intensity, time since abandonment, and stand conditions affect the species richness and community composition of ectomycorrhizal fungi. We surveyed fruit bodies on three 10 m × 10 m study plots in 36 sites…
A financial feasibility study of an aquaponic system in a Mediterranean urban context
2019
Abstract Aquaponics is largely recognized as a solution for sustainable food production as it follows a biomimetic natural system and the circular economy principles, allowing large food productivity on nonagricultural land, and at the same time strongly reducing inputs and waste. In this study, we collected technical, economic and production data from a pilot aquaponic plant producing lettuce (Lactuca sativa) and Nile tilapia (Oreochromis niloticus) realized in an urban context in Sicily (Southern Italy), very suitable area for aquaponic production in relation to the Mediterranean climate. Through the determination of Net return and Break Even Point, analysing on one side the items which c…