Search results for "Ecological model"
showing 10 items of 322 documents
F.A.L.C.A.D.E.: a fuzzy software for the energy and environmental balances of products
2004
Abstract It is generally well known that the reliability of Life Cycle Analysis (LCA) studies depends upon exact, complete and sharp input data that, unfortunately, are not always available. Furthermore, when available, the input data are affected by uncertainty whose importance is not always adequately taken into consideration. This paper describes the software F.A.L.C.A.D.E. (Fuzzy Approach to Life Cycle Analysis and Decision Environment): a tool designed for the calculation of the eco-profile of products, based on a fuzzy logic approach. The originality of the method already treated in other papers is to use the fuzzy representation to manage the complex relationships that arise in compi…
Extreme thermophilic (70°C), VFA-fed UASB reactor: performance, temperature response, load potential and comparison with 35 and 55°C UASB reactors
1999
Abstract The paper evaluates the reactor performance, load potential and temperature response of a 70°C, VFAs-fed UASB reactor, seeded with mesophilic granular sludge. Batch experiments were, in addition, conducted to assess the effect of temperature on the achievable residual VFAs in the 70°C effluent. The performance of similarly-fed and seeded 35 and 55°C UASB reactors was also tested. At a short HRT (2–3 h) and a moderate VLR of 12–20 g COD l−1 d−1, the 70°C UASB achieved 66–74% VFAs removal (acetate and butyrate 84–90%, propionate
Responses of soil carbon and nitrogen transformations to stump removal
2012
We studied in central Finland whether stump harvesting after clear felling of coniferous forest poses further short-term changes in soil carbon and nitrogen dynamics when compared to the traditional site preparation method, mounding. Exposed mineral soil patches in Norway spruce (Picea abies) dominated clear-cut stands were sampled 1â5 years after the treatments. The extent of the exposed mineral soil surface was significantly larger at the stump removal sites when compared to the mounding sites. No differences were found in soil pH, organic matter content or total concentration of soil C between the treatments or treatment years. Total concentration of soil N was consistently higher and …
DESASS: A software tool for designing, simulating and optimising WWTPs
2008
This paper presents a very useful software tool to design, simulate and optimise wastewater treatment plants. The program is called DESASS (DEsign and Simulation of Activated Sludge Systems) and has been developed by CALAGUA research group. The mathematical model implemented is the Biological Nutrient Removal Model No.1 (BNRM1) which allows simulating the most important physical, chemical and biological processes taking place in treatment plants. DESASS calculates the performance under steady or transient state of whole treatment schemes including primary settlers, volatile fatty acid generation systems by primary sludge fermentation, activated sludge systems for biological organic matter a…
Distribution of volatile organic compounds in Sicilian groundwaters analysed by head space-solid phase micro extraction coupled with gas chromatograp…
2008
This work presents the results of an assessment of the existence and concentration of 13 volatile organic compounds (VOCs) in groundwaters from 14 hydrological basins in Sicily (25,710km (2)). On the basis of hydrological, hydrogeochemical and geological studies, 324 sampling points were selected. All groundwater sampled were collected twice, from October to December 2004 and from February to May 2005, and were analysed to determine the concentration and spatial distribution of the VOCs in the aquifers. The need to analyze a large number of samples in a short space of time so as to obtain quantitative analyses in trace concentration levels spurred us to create a new analytical method, both …
Linking food webs to ecosystem processes: Piecewise linear models of soil microcosms
2008
Abstract A piecewise linear approach to link decomposer biomass and soil nitrogen dynamics is proposed. Dynamics of a detritus–fungus–nematode food chain were studied in a microcosm experiment and modelled to evaluate the role of fungal-feeding nematodes in N mineralization. The nematode dynamics switched from exponential growth to a resource-limited phase. At the same time the amount of ammonium nitrogen in soil started to increase, following an initial immobilization phase. Both nematode and ammonium dynamics could be described by two-phase linear equations. Two nitrogen models were compared. A model in which the nematode accounted for all mineralization could be fitted to the ammonium da…
The conservation potential of brook-side key habitats in managed boreal forests
2011
Today, maintaining biodiversity is included in the targets of boreal forest management. A widespread approach in northern Europe is to identify and preserve woodland key habitats within managed forests. Woodland key habitats are expected to be patches that host populations of threatened and declining species, and the preservation of these patches is assumed to enable the persistence of the focal species in the landscape. In Finland, the criteria for selecting woodland key habitats are defined in the Finnish Forest Act, and the selection has been done by forest practitioners. Our objective was to determine whether the surroundings of boreal brooks and rivulets qualified as key habitats are t…
Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs
2014
Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce ( (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest o…
The use of Markovian metapopulation models: Reducing the dimensionality of transition matrices by self-organizing Kohonen networks
2006
Abstract Markovian population models are used in conservation biology to find an accurate estimate of a population's extinction probability. Such models require handling of large transition matrices and calculations are thus extremely time-consuming when large populations have to be studied. To accomplish these problems, some authors have suggested to group together several states/sizes of the population. Unfortunately, this so-called binning frequently results in errors in estimates obtained. The main problem with binning is that it assumes that grouped states behave nearly identical with respect to the underlying stochastic population process and that so far binning methods implicitly vio…
Monitoring fungal biodiversity – towards an integrated approach
2012
Biodiversity information databases and platforms have seen considerable progress in recent years. They have a high potential in conservation science in general, but may be even more revolutionary in relation to poorly known species groups such as fungi, whose practical conservation work has been jeopardised by scattered and poorly controlled information. We review the tradition of collecting information on species occurrences in mycology and discuss the characteristics of the present fungal biodiversity information databases. With a special focus on population trend monitoring of fruit body producing macrofungi, we emphasise several unrealised opportunities of these databases and point out …