Search results for "Dynamic"
showing 10 items of 12329 documents
From individual dispersal to species ranges: perspectives for a changing world.
2006
Dispersal is often risky to the individual, yet the long-term survival of populations depends on having a sufficient number of individuals that move, find each other, and locate suitable breeding habitats. This tension has consequences that rarely meet our conservation or management goals. This is particularly true in changing environments, which makes the study of dispersal urgently topical in a world plagued with habitat loss, climate change, and species introductions. Despite the difficulty of tracking mobile individuals over potentially vast ranges, recent research has revealed a multitude of ways in which dispersal evolution can either constrain, or accelerate, species' responses to en…
Hydrodynamic characterization of a new small-scale reactor mixed by a magnetic bar
2015
International audience; The purpose of this study was to evaluate the mixing characteristics of a new milliliter-scale (mL-scale) reactor developed for studying enzymatic activity or physiological cell response. The mL-scale reactor was designed to enable the integration of several sensors to carry out dynamic measurements in a controlled environment. Rapid homogeneity of the entire system is essential to ensure reproducible and reliable results, consequently the reactor was stirred to optimize both mass and heat transfers. A comparative study using three different techniques was undertaken to study mixing performances in the system. Firstly, mixing time (4,) was estimated in the reactor us…
Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction
2016
Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus i…
Dynamic Energy Budget provides mechanistic derived quantities to implement the ecosystem based management approach
2019
Abstract The on-going climate change threats are rapidly growing at both global and local scales, affecting ecosystems, societies and economies by altering natural distribution and productivity of key commercial species. Although the ecosystem based management (EBM) focuses on ecosystem equilibria, to provide realistic management measures for important activities at sea such as fisheries and aquaculture, there is a need of quantities; mechanistic approaches are suggested as reliable solutions. Here, a Dynamic Energetic Budget (DEB) application studies the link between environmental change (temperature forecasted increasing scenario in a context of COP 21 [Paris climate conference Agreement]…
Simple learning rules to cope with changing environments
2008
10 pages; International audience; We consider an agent that must choose repeatedly among several actions. Each action has a certain probability of giving the agent an energy reward, and costs may be associated with switching between actions. The agent does not know which action has the highest reward probability, and the probabilities change randomly over time. We study two learning rules that have been widely used to model decision-making processes in animals-one deterministic and the other stochastic. In particular, we examine the influence of the rules' 'learning rate' on the agent's energy gain. We compare the performance of each rule with the best performance attainable when the agent …
Demographic responses of a site-faithful and territorial predator to its fluctuating prey: long-tailed skuas and arctic lemmings.
2014
Summary1. Environmental variability, through interannual variation in food availability or climaticvariables, is usually detrimental to population growth. It can even select for constancy in keylife-history traits, though some exceptions are known. Changes in the level of environmentalvariability are therefore important to predict population growth or life-history evolution.Recently, several cyclic vole and lemming populations have shown large dynamical changesthat might affect the demography or life-histories of rodent predators.2. Skuas constitute an important case study among rodent predators, because of theirstrongly saturating breeding productivity (they lay only two eggs) and high deg…
A global perspective on the climate‐driven growth synchrony of neighbouring trees
2020
2 .pdf files: File 1. Author's article final version, Post-Print (19 Pags.- 4 Figs.- 2 Tabls.). File 2. Supplementary Materials (3 Figs.- 2 Tabls.- 1 Model Equation).
The effect of the quality of diet on the functional response of Mytilus galloprovincialis (Lamarck, 1819): Implications for integrated multitrophic a…
2017
Abstract The integrated multi-trophic aquaculture (i.e., IMTA) is a practice combining organisms with different trophic levels with the final purpose of transforming the continuous waste of food by targeting species into nutrient input for other non-target species. This practice very often involves filter feeders, such as bivalves, by the use of which bioenergetics budgets are strongly influenced by the quality and quantity of different foods. However, to date, scant information is available, to really understand the rebounds of food availability on the growth performances of these harvested biomasses in the natural environment. By choosing the mussel Mytilus galloprovincialis as a model, t…
The asexual enchytraeid worm Cognettia sphagnetorum (Oligochaeta) has increased Cu resistance in polluted soil
2001
We studied Cu resistance in the asexual (reproduction through fragmentation) enchytraeid worms (Cognettia sphagnetorum, Oligochaeta) originating from two sites: one uncontaminated, and another contaminated by heavy metals. Adult worms were smaller and population density was lower at the polluted site. However, adults from the contaminated site had better survival in Cu-contaminated soil, but lower survival as juveniles (fragments). As we do not know the genetic basis of Cu resistance of the worms, it may have been reached by acclimatization via induced Cu regulation. Because fragmentation is the only mode of reproduction, all phenotypic properties (including resistance) of a parental genera…
Species composition and richness of aphid parasitoid wasps in cotton fields in northern China
2017
AbstractThe cotton aphid, Aphis gossypii (Hemiptera: Aphididae), is a serious pest of cotton across the globe, particularly in the cotton agroecosystems of northern China. Parasitic wasps are deemed to be important natural enemies of A. gossypii, but limited information exists about their species composition, richness and seasonal dynamics in northern China. In this study, we combine sampling over a broad geographical area with intensive field trials over the course of three cropping seasons to describe parasitoid-hyperparasitoid communities in cotton crops. We delineate a speciose complex of primary parasitoids and hyperparasitoids associated with A. gossypii. Over 90% of the primary paras…