The Experts below are selected from a list of 215877 Experts worldwide ranked by ideXlab platform
I S Mettrop - One of the best experts on this subject based on the ideXlab platform.
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the Ecological Effects of water level fluctuation and phosphate enrichment in mesotrophic peatlands are strongly mediated by soil chemistry
Ecological Engineering, 2015Co-Authors: I S Mettrop, Melchior D Rutte, A M Kooijman, Leon P M LamersAbstract:Abstract Since the re-establishment of a more natural water regime is considered by water management in wetlands with artificially stable water levels, the biogeochemical and Ecological Effects of water level fluctuation with different nutrient loads should be investigated. This is particularly important for biodiverse mesotrophic fens, sensitive to acidification and eutrophication. Mesocosm experiments were conducted to study the interactive Effects of water level fluctuation and P-enrichment under controlled summer conditions, using peat cores including vegetation from three fens differing in biogeochemical characteristics. The Effects of fluctuating water levels on biogeochemistry and vegetation appeared to be highly dependent on peat chemistry, and more important than the Effects of P-enrichment. Only when plant growth was stimulated by a favorable water level regime, P-enrichment led to increased P-consumption by plants. In rich fens with a high soil Ca-content, 7 weeks of lowered water table (−15 cm) did not lead to a drop in pH. However, soil subsidence, increased N-availability and decline of the rich fen bryophyte Scorpidium scorpioides give cause to concern. 7 weeks of inundation (+15 cm) offered possibilities for restoration in these fens, since alkalinity and Ca-concentrations increased, while soil P-mobilization did not occur. Even P-enrichment did not result in increased P-availability, presumably due to Ca-related precipitation of P. In rich fens with a high soil Fe-content, water table lowering should be avoided as well, because of soil subsidence, increased N-availability, decline of the rich fen bryophyte Calliergon giganteum , plus acidification due to Fe-oxidation. Shallow inundation, however, is also harmful, especially after mowing and with P-rich water, because plant growth was hampered, presumably by toxicity of NH 4 + and/or Fe(II). In mineral-poor fens with a high soil P- and S-content, shallow inundation should be avoided, because of tremendous internal P-mobilization. Vitality of the dominant bryophyte Sphagnum palustre , however, was not affected. Low water tables affected neither vegetation, nor biogeochemistry, showing resistance to short-term drought in these fens. Given the strong mediating effect of soil chemistry, risks and benefits of re-establishment of fluctuating water levels with clean or P-rich water need to be considered for different fen types separately in water and nature management.
Joshua S Weitz - One of the best experts on this subject based on the ideXlab platform.
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the virus of my virus is my friend Ecological Effects of virophage with alternative modes of coinfection
Journal of Theoretical Biology, 2014Co-Authors: Bradford P Taylor, Michael H Cortez, Joshua S WeitzAbstract:Virophages are viruses that rely on the replication machinery of other viruses to reproduce within eukaryotic hosts. Two different modes of coinfection have been posited based on experimental observation. In one mode, the virophage and the virus enter the host independently. In the other mode, the virophage adheres to the virus so both virophage and virus enter the host together. Here we ask: what are the Ecological Effects of these different modes of coinfection? In particular, what Ecological Effects are common to both infection modes, and what are the differences particular to each mode? We develop a pair of biophysically motivated ODE models of viral-host population dynamics, corresponding to dynamics arising from each mode of infection. We find that both modes of coinfection allow for the coexistence of the virophage, virus, and host either at a stable fixed point or through cyclical dynamics. In both models, virophage tends to be the most abundant population and their presence always reduces the viral abundance and increases the host abundance. However, we do find qualitative differences between models. For example, via extensive sampling of biologically relevant parameter space, we only observe bistability when the virophage and the virus enter the host together. We discuss how such differences may be leveraged to help identify modes of infection in natural environments from population level data.
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the virus of my virus is my friend Ecological Effects of virophage with alternative modes of coinfection
arXiv: Populations and Evolution, 2013Co-Authors: Bradford P Taylor, Michael H Cortez, Joshua S WeitzAbstract:Virophages are viruses that rely on the replication machinery of other viruses to reproduce within eukaryotic hosts. Two different modes of coinfection have been posited based on experimental observation. In one mode, the virophage and virus enter the host independently. In the other mode, the virophage adheres to the virus so both virophage and virus enter the host together. Here we ask: what are the Ecological Effects of these different modes of coinfection? In particular, what Ecological Effects are common to both infection modes, and what are the differences particular to each mode? We develop a pair of biophysically motivated ODE models of viral-host population dynamics, corresponding to dynamics arising from each mode of infection. We find both modes of coinfection allow for the coexistence of the virophage, virus, and host either at a stable fixed point or through cyclical dynamics. In both models, virophage tend to be the most abundant population and their presence always reduces the viral abundance and increases the host abundance. However, we do find qualitative differences between models. For example, via extensive sampling of biologically relevant parameter space, we only observe bistability when the virophage and virus enter the host together. We discuss how such differences may be leveraged to help identify modes of infection in natural environments from population level data.
Carlos Lopez-vaamonde - One of the best experts on this subject based on the ideXlab platform.
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Ecological Effects of invasive alien insects
Biological Invasions, 2009Co-Authors: Marc Kenis, Marie-anne Auger-rozenberg, Alain Roques, Laura Timms, Christelle Péré, Matthew J. W. Cock, Josef Settele, Sylvie Augustin, Carlos Lopez-vaamondeAbstract:A literature survey identified 403 primary research publications that investigated the Ecological Effects of invasive alien insects and/or the mechanisms underlying these Effects. The majority of these studies were published in the last 8 years and nearly two-thirds were carried out in North America. These publications concerned 72 invasive insect species, of which two ant species, Solenopsis invicta and Linepithema humile , accounted for 18% and 14% of the studies, respectively. Most publications investigated Effects on native biodiversity at population or community level. Genetic Effects and, to a lesser extent, Effects on ecosystem services and processes were rarely explored. We review the Effects caused by different insect invaders according to: their ecosystem roles, i.e. herbivores, predators, parasites, parasitoids and pollinators; the level of biological organisation at which they occur; and the direct and indirect mechanisms underlying these Effects. The best documented Effects occur in invasive ants, Eurasian forest herbivores invasive in North America, and honeybees. Impacts may occur through simple trophic interactions such as herbivory, predation or parasitism. Alien species may also affect native species and communities through more complex mechanisms such as competition for resources, disease transmission, apparent competition, or pollination disruption, among others. Finally, some invasive insects, particularly forest herbivores and ants, are known to affect ecosystem processes through cascading Effects. We identify biases and gaps in our knowledge of Ecological Effects of invasive insects and suggest further opportunities for research.
Marjorie C Wellman - One of the best experts on this subject based on the ideXlab platform.
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aquatox modeling environmental fate and Ecological Effects in aquatic ecosystems
Ecological Modelling, 2008Co-Authors: Richard A Park, Jonathan S Clough, Marjorie C WellmanAbstract:AQUATOX combines aquatic ecosystem, chemical fate, and ecotoxicological constructs to obtain a truly integrative fate and Effects model. It is a general, mechanistic Ecological risk assessment model intended to be used to evaluate past, present, and future direct and indirect Effects from various stressors including nutrients, organic wastes, sediments, toxic organic chemicals, flow, and temperature in aquatic ecosystems. The model has a very flexible structure and provides multiple analytical tools useful for evaluating Ecological Effects, including uncertainty analysis, nominal range sensitivity analysis, comparison of perturbed and control simulations, and graphing and tabulation of predicted concentrations, rates, and photosynthetic limitations. It can represent a full aquatic food web, including multiple genera and guilds of periphyton, phytoplankton, submersed aquatic vegetation, invertebrates, and fish and associated organic toxicants. It can model up to 20 organic chemicals simultaneously. (It does not model metals.) Modeled processes for organic toxicants include chemodynamics of neutral and ionized organic chemicals, bioaccumulation as a function of sorption and bioenergetics, biotransformation to daughter products, and sublethal and lethal toxicity. It has an extensive library of default biotic, chemical, and toxicological parameters and incorporates the ICE regression equations for estimating toxicity in numerous organisms. The model has been implemented for streams, small rivers, ponds, lakes, reservoirs, and estuaries. It is an integral part of the BASINS system with linkage to the watershed models HSPF and SWAT.
Philipp Fischer - One of the best experts on this subject based on the ideXlab platform.
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Ecological Effects of water level fluctuations in lakes an urgent issue
Hydrobiologia, 2008Co-Authors: Karl M Wantzen, Karlotto Rothhaupt, Martin Mortl, Marco Cantonati, Laszlo Toth, Philipp FischerAbstract:Water-level fluctuations (WLF) affect the Ecological processes and patterns of lakes in several ways. Aquatic habitats and feeding or breeding grounds are gained or lost, as light, climate and wave impacts change to mention only a few phenomena. While the phenomenon of WLF has been studied in many rivers (better known as flood pulse, Junk & Wantzen, 2004) and environmental flows (Coops et al., 2003), so far it has not received due attention in lakes (Coops et al., 2003). A potential reason for why WLF in lakes have been overlooked for such a long time may be that central Europe and North America—the cradles of limnological research—are situated in landscapes which have been shaped by man for long time. Most central European lakes have been regulated since the middle ages; therefore, naturally fluctuating lakes such as Lake Constance (Fig. 1) are rare today.
