Search results for "Fishe"
showing 10 items of 2001 documents
Mixed company : a framework for understanding the composition and organization of mixed‐species animal groups
2020
Mixed‐species animal groups (MSGs) are widely acknowledged to increase predator avoidance and foraging efficiency, among other benefits, and thereby increase participants' fitness. Diversity in MSG composition ranges from two to 70 species of very similar or completely different phenotypes. Yet consistency in organization is also observable in that one or a few species usually have disproportionate importance for MSG formation and/or maintenance. We propose a two‐dimensional framework for understanding this diversity and consistency, concentrating on the types of interactions possible between two individuals, usually of different species. One axis represents the similarity of benefit types …
Exploring individual and population eco-evolutionary feedbacks under the coupled effects of fishing and predation
2020
Intensive fishing that selects for large and old individuals can have pervasive effects on traits directly associated with the fecundity and survival of the target species. The observed reduction in fish body size can result in earlier sexual maturity at a smaller body size, leading to a lower individual reproductive output and population productivity in the long term. In addition, increased predation can induce similar responses in age and size at maturity due to the release of intraspecific competition and the lower population density. Thus, the combined impact of fisheries and predation is more difficult to predict due to their competition for fish, ultimately limiting and directing the …
Sediments as Factor in the Fate of the Threatened Endemic Fish Species Romanichthys Valsanicola Dumitrescu, Bănărescu and Stoica, 1957 (Vâlsan River …
2020
Abstract The main emphasis of this paper is on the negative effects of sedimentation on the most highly endangered fish of Europe Romanichthys valsanicola and the habitats of its main trophic resource Rhithrogena semicolorata. Some inexpensive and easy-to-implement solutions are identified and proposed (dam reservoir related recommendations for basin sediments management, forestry related recommendations for sediment basin management, basin sediments general management recommendations, riverbed ecological reconstruction approach proposal, etc.) in the paper with the same conservative purpose for Romanichthys valsanicola species in the actual situation of habitat loss and drastic regress of …
Interaction between diclofop-methyl and 2,4-D in wild oat (Avena fatua L.) and cultivated oat (Avena sativa L.), and fate of diclofop-methyl in culti…
1989
Summary Influence of 2,4-D on toxicity of diclofop-methyl to Avena sativa (cv. Selma) and Arena fatua at 2·5 leaf stage has been evaluated under controlled conditions. Effects of 2,4-D on the fate of diclofop-methyl in cultivated oat have also been studied. Mixture with 2,4-D reduced the toxicity of diclofop-methyl to both species. When applied immediately after diclofop-methyl treatment, 2,4-D still reduced herbicide toxicity to wild oat. This reduction was smaller in cultivated oat. and was only observed at higher phytotoxicity. No interaction was observed when a 10-day period separated the two applications. In mixture, 2,4-D enhanced diclofop-methyl penetration and diclofop acid conjugat…
DNA barcoding of marine fishes from Saudi Arabian waters of the Gulf
2019
We used the cytochrome oxidase subunit I (coI) gene DNA to barcode 117 endemic Gulf and cosmopolitan Indo-West Pacific fish species belonging to 54 families and 13 orders. Novel DNA barcodes were provided for 18 fish species (Trachinocephalus sp., Nematalosa sp., Herklotsichthys lossei, Upeneus doriae, Trachurus indicus, Apogonichthyoides taeniatus, Verulux cypselurus, Favonigobius sp., Suezichthus gracilis, Sillago sp., Brachirus orientalis, Pegusa sp., Lepidotrigla bispinosa, Lepidotrigla sp., Grammoplites suppositus, Hippichthys sp., Paramonacanthus sp. and Triacanthus sp.). The species delimitation analysis, conducted with Poisson tree processes- Bayesian PTP (PTP-bPTP) and nucleotide-d…
Effect of Agronomic Practices on Yield and Quality of Borage at Harvest and During Storage as Minimally-Processed Produce
2020
Borage (Borago officinalis L.) is a hairy pubescent herb known throughout the world for its folk medicinal uses, as well as for many culinary uses. There is still little information on the cultivation needs of this species, especially for its use as vegetable crop and as fresh-cut produce. Hence, the aim of the research was to study the effects of agronomic practices on yield and quality of borage and on the storability as minimally-processed product. Two experiments were carried out in two consecutive years in order to evaluate the effect of plant density and plastic mulching on yield and quality of two borage accessions at harvest and during storage as minimally-processed produce for 14 d…
Carbon partitioning in a walnut-maize agroforestry system through arbuscular mycorrhizal fungi
2020
National audience; In tree-based intercropping systems, roots of trees and crops are interacting and could influence ecosystem services provided by soil microorganisms. Here, the analysis of diversity of arbuscular mycorrhiza fungi (AMF) associated with roots of walnut and maize reveals differences. Of interest, Funneliformis genus is mainly associated with maize roots, and one OTU related to an uncultured Glomus, might form a common mycorrhizal network linking roots of both plants. In addition, the analysis of 13C of mycelium living in the surrounding environment of roots, suggest that part of the carbon derived from walnut trees could be transferred to maize plants. Our results suggest th…
Which traits allow weed species to persist in grass margin strips ?
2017
EASPEGESTADINRA; Sown-grass margin strips, historically established to limit pesticide drift and soil erosion, are now also promoted for enhancing floral diversity and associated ecosystem services. To better understand weed community assembly in grass margin strips, we performed floral surveys in 75 sown-grass margin strips in two regions in France and characterized each species using information from trait databases. We hypothesized that traits of dominant species would differ between newly sown-grass margin strips and older strips. Weed species were separated into functional groups based on their traits using multiple correspondence analysis and hierarchical ascendant classification. Fun…
The “Porţile de Fier/Iron Gates” Nature Park (Romania) Some Danube Northern Tributaries Fish Fauna
2014
Abstract The relative larger size of the Berzasca River, respectively the relatively constant environmental conditions, with relatively stenotopic ichthyocenosis, suffered small qualitative and quantitative fish fauna modifications in time, compared to the smaller rivers such as Sirinia, Liubcova/Oreviţa and Mraconia. The Danube “Iron Gates” I Lake influences the lower sectors of the studied rivers in term of fish species exchange. The accidental droughts in the karstic zones of the studied lotic sectors have a negative influence on the spatial continuity of the local fish fauna, and the climate change can increase these influence in the future. All the studied rivers play an important role…
Spatial Variation of Soil Seed Bank under Cushion Plants in a Subalpine Degraded Grassland
2017
Cushion plants can affect wind speed and sediment movement patterns which probably modify the water and sediment redistribution along slopes and increase the accumulation of seeds under and around their canopies. This study was carried out to assess the spatial variability of soil seed bank (SSB) and seed bank composition around cushion plants to estimate the SSB potential for restoration of degraded area. Twenty cushions of Onobrychis cornuta were selected in a mountainous rangelands in northern Alborz in Iran, measuring density, richness and composition of SSB at four locations of each cushion (upslope edge, downslope edge, center and outside). SSB composition and density were determined …