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1.
PLoS Comput Biol ; 18(1): e1009777, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35073313

RESUMO

Individual-based modeling is widely applied to investigate the ecological mechanisms driving microbial community dynamics. In such models, the population or community dynamics emerge from the behavior and interplay of individual entities, which are simulated according to a predefined set of rules. If the rules that govern the behavior of individuals are based on generic and mechanistically sound principles, the models are referred to as next-generation individual-based models. These models perform particularly well in recapitulating actual ecological dynamics. However, implementation of such models is time-consuming and requires proficiency in programming or in using specific software, which likely hinders a broader application of this powerful method. Here we present McComedy, a modeling tool designed to facilitate the development of next-generation individual-based models of microbial consumer-resource systems. This tool allows flexibly combining pre-implemented building blocks that represent physical and biological processes. The ability of McComedy to capture the essential dynamics of microbial consumer-resource systems is demonstrated by reproducing and furthermore adding to the results of two distinct studies from the literature. With this article, we provide a versatile tool for developing next-generation individual-based models that can foster understanding of microbial ecology in both research and education.


Assuntos
Biologia Computacional/métodos , Microbiota , Interface Usuário-Computador , Software
2.
Eur J Orthod ; 44(3): 279-286, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34532733

RESUMO

OBJECTIVE: The aim of this study was to evaluate intraoral scanning (IOS) in infants, neonates, and small children with craniofacial anomalies for its feasibility, scanning duration, and success rate. Impression taking in vulnerable patients can be potentially life-threatening, with the risk of airway obstruction and aspiration of impression material. The advantage of increasingly digitalized dentistry is demonstrated. MATERIALS AND METHODS: IOS was captured with the Trios 3® (3Shape, Copenhagen, Denmark) intraoral scanner. The underlying disorders were divided into cleft lip and palate (CLP), Trisomy 21 (T21), Robin Sequence (RS), Treacher Collins syndrome (TC), and isolated mandibular retrognathia (MR). Scan data were analysed by scanning duration, number of images, possible correlations of these factors with the different craniofacial disorders, patient age, and relationship between first and subsequent scans. Clinical experiences with the repeated digital impressions are described. RESULTS: Patient data of 141 scans in 83 patients were analysed within an 11-month period. Patients had a median age of 137 days. Median scanning duration was 138 seconds, resulting in a median of 352 images. There was a statistically significant difference in scanning duration (P = 0.001) between infants and neonates. IOS took longest in patients with CLP (537 seconds) and shortest in T21 patients (21 seconds), although there was no statistically significant difference between aetiologies. There was no statistically significant difference between first and subsequent scans in scanning duration. In four cases the IOS had to be repeated, and one patient ultimately required conventional impression taking (all CLP patients; success rate 94%). No severe adverse events occurred. CONCLUSION: IOS is a fast, safe, and feasible procedure for neonates, small children, and infants with craniofacial malformations. One special challenge for both technician and user was identified in patients with CLP, though implementing this new approach of digital impression taking was otherwise found to be highly successful in everyday clinical routine.


Assuntos
Fenda Labial , Fissura Palatina , Anormalidades Craniofaciais , Criança , Fenda Labial/diagnóstico por imagem , Fissura Palatina/diagnóstico por imagem , Desenho Assistido por Computador , Anormalidades Craniofaciais/diagnóstico por imagem , Técnica de Moldagem Odontológica , Estudos de Viabilidade , Humanos , Imageamento Tridimensional , Lactente , Recém-Nascido
3.
Environ Model Softw ; 135: 104885, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33041631

RESUMO

System-of-systems approaches for integrated assessments have become prevalent in recent years. Such approaches integrate a variety of models from different disciplines and modeling paradigms to represent a socio-environmental (or social-ecological) system aiming to holistically inform policy and decision-making processes. Central to the system-of-systems approaches is the representation of systems in a multi-tier framework with nested scales. Current modeling paradigms, however, have disciplinary-specific lineage, leading to inconsistencies in the conceptualization and integration of socio-environmental systems. In this paper, a multidisciplinary team of researchers, from engineering, natural and social sciences, have come together to detail socio-technical practices and challenges that arise in the consideration of scale throughout the socio-environmental modeling process. We identify key paths forward, focused on explicit consideration of scale and uncertainty, strengthening interdisciplinary communication, and improvement of the documentation process. We call for a grand vision (and commensurate funding) for holistic system-of-systems research that engages researchers, stakeholders, and policy makers in a multi-tiered process for the co-creation of knowledge and solutions to major socio-environmental problems.

4.
BMC Oral Health ; 21(1): 400, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34399746

RESUMO

BACKGROUND: Lyme disease is the most frequent tick-borne infectious disease in Europe. It often presents with a wide variety of symptoms. For this reason, affection of the temporomandibular joint (TMJ) caused by Lyme disease (LD) can be misdiagnosed as a common temporomandibular disorder (TMD). CASE PRESENTATION: The purpose of this case report of a 25-year-old woman presenting to the Departments of Orthodontics and Oral and Maxillofacial Surgery with extensive symptoms of temporomandibular disorder is to illustrate the delayed diagnosis of Lyme disease which was only made after extensive therapy of the temporomandibular joint. The specialist literature only reports a few cases of patients suffering from Lyme disease with TMJ manifestations. CONCLUSION: This case report and the relevant literature review aim to emphasize the importance of accurate request of medical history and differential diagnosis of acute TMJ arthritis and arthralgia. Early interdisciplinary diagnosis of Lyme disease and early antibiotic therapy are essential to avoid misdiagnosis and unnecessary, sometimes invasive, therapies.


Assuntos
Artrite , Doença de Lyme , Transtornos da Articulação Temporomandibular , Adulto , Artralgia , Feminino , Humanos , Doença de Lyme/complicações , Doença de Lyme/diagnóstico , Doença de Lyme/tratamento farmacológico , Articulação Temporomandibular , Transtornos da Articulação Temporomandibular/diagnóstico , Transtornos da Articulação Temporomandibular/etiologia
6.
J Proteome Res ; 16(4): 1593-1604, 2017 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-28252966

RESUMO

The gastrointestinal microbiota in the gut interacts metabolically and immunologically with the host tissue in the contact zone of the mucus layer. For understanding the details of these interactions and especially their dynamics it is crucial to identify the metabolically active subset of the microbiome. This became possible by the development of stable isotope probing techniques, which have only sparsely been applied to microbiome research. We applied the in vivo stable isotope approach using 15N-labeled diet with subsequent identification of metabolically active bacterial species. Four-week old male Sprague-Dawley rats were randomly assigned to chow diet (CD, n =15) and high-fat diet (HFD, n =15). After 11 weeks, three animals from each group were sacrificed for baseline characterization of anthropometric and metabolic obesity. The remaining animals were exposed to either a 15N-labeled (n =9) or a 14N-unlabeled experimental diet (n =3). Three rats from each cohort (HFD and CD) were sacrificed at 12, 24, and 72 h. The remaining three animals from each cohort, which received the 14N-unlabeled diet, were sacrificed after 72 h. The colon was harvested and divided into three equal sections (proximal, medial, and distal), and the mucus layer of each specimen was sampled by scraping. We identified the active subset in an HFD model of obesity in comparison with lean controls rats using metaproteomics. In addition, all samples were investigated by 16S rRNA amplicon gene sequencing. The active microbiome of the HFD group showed an increase in bacterial taxa for Verrucomicrobia and Desulfovibrionaceae. In contrast with no significant changes in alpha diversity, time- and localization-dependent effects in beta-diversity were clearly observed. In terms of enzymatic functions the HFD group showed strong affected metabolic pathways such as energy production and carbohydrate metabolism. In vivo isotope labeling combined with metaproteomics provides a valuable method to distinguish the active from the non-active bacterial phylogenetic groups that are relevant for microbiota-host interaction. For morbid obesity such analysis may provide potentially new strategies for targeted pre- or probiotic treatments.


Assuntos
Microbioma Gastrointestinal/genética , Trato Gastrointestinal/microbiologia , Redes e Vias Metabólicas/genética , Verrucomicrobia/genética , Animais , Dieta Hiperlipídica , Interações Hospedeiro-Patógeno/genética , Marcação por Isótopo , Mucosa/microbiologia , RNA Ribossômico 16S/genética , Ratos , Ratos Sprague-Dawley , Verrucomicrobia/isolamento & purificação
7.
Appl Environ Microbiol ; 82(10): 2902-2908, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-26944849

RESUMO

Fungal mycelia serve as effective dispersal networks for bacteria in water-unsaturated environments, thereby allowing bacteria to maintain important functions, such as biodegradation. However, poor knowledge exists on the effects of dispersal networks at various osmotic (Ψo) and matric (Ψm) potentials, which contribute to the water potential mainly in terrestrial soil environments. Here we studied the effects of artificial mycelium-like dispersal networks on bacterial dispersal dynamics and subsequent effects on growth and benzoate biodegradation at ΔΨo and ΔΨm values between 0 and -1.5 MPa. In a multiple-microcosm approach, we used a green fluorescent protein (GFP)-tagged derivative of the soil bacterium Pseudomonas putida KT2440 as a model organism and sodium benzoate as a representative of polar aromatic contaminants. We found that decreasing ΔΨo and ΔΨm values slowed bacterial dispersal in the system, leading to decelerated growth and benzoate degradation. In contrast, dispersal networks facilitated bacterial movement at ΔΨo and ΔΨm values between 0 and -0.5 MPa and thus improved the absolute biodegradation performance by up to 52 and 119% for ΔΨo and ΔΨm, respectively. This strong functional interrelationship was further emphasized by a high positive correlation between population dispersal, population growth, and degradation. We propose that dispersal networks may sustain the functionality of microbial ecosystems at low osmotic and matric potentials.


Assuntos
Benzoatos/metabolismo , Ecossistema , Fungos/crescimento & desenvolvimento , Micélio/crescimento & desenvolvimento , Pseudomonas putida/metabolismo , Microbiologia da Água , Água/química , Biotransformação , Genes Reporter , Proteínas de Fluorescência Verde/análise , Pseudomonas putida/crescimento & desenvolvimento , Coloração e Rotulagem
8.
Ecology ; 97(11): 3143-3153, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27870022

RESUMO

Theory on viability of small populations is well developed and has led to the standard methodology of population viability analysis (PVA) to assess vulnerability of single species. However, more complex situations involving community dynamics or environmental change violate theoretical assumptions. Synthesizing concepts from population, community, and conservation ecology, we develop a generic theory on the viability of cyclic populations. The interplay of periodic population decline and demography causes varying risk patterns that aggregate during cycles and modify the temporal structure of viability. This variability is visualized and quantitatively assessed. For two standard viability metrics that summarize immediate extinction risk and the general long-term conditions of populations, we mathematically describe the impact of population cycles. Finally, we suggest and demonstrate PVA for cyclic populations that respond to, e.g., seasonality, interannual variation, or trophic interactions. Our theoretical and methodological advancement opens a route to viability analysis in food webs and trophic meta-communities and equips biodiversity conservation with a long-missing tool.


Assuntos
Modelos Biológicos , Periodicidade , Animais , Extinção Biológica , Dinâmica Populacional , Estações do Ano
9.
Trends Ecol Evol ; 38(11): 1051-1059, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37558537

RESUMO

Assessing and predicting the persistence of populations is essential for the conservation and control of species. Here, we argue that local mechanisms require a better conceptual synthesis to facilitate a more holistic consideration along with regional mechanisms known from metapopulation theory. We summarise the evidence for local buffer mechanisms along with their capacities and emphasise the need to include multiple buffer mechanisms in studies of population persistence. We propose an accessible framework for local buffer mechanisms that distinguishes between damping (reducing fluctuations in population size) and repelling (reducing population declines) mechanisms. We highlight opportunities for empirical and modelling studies to investigate the interactions and capacities of buffer mechanisms to facilitate better ecological understanding in times of ecological upheaval.

10.
Microb Ecol ; 63(2): 339-47, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21826490

RESUMO

Bacterial degradation is an ecosystem service that offers a promising method for the remediation of contaminated soils. To assess the dynamics and efficiency of bacterial degradation, reliable microbial simulation models, along with the relevant processes, are required. We present an approach aimed at improving reliability by studying the relevance and implications of an important concept from theoretical ecology in the context of a bacterial system: conditional dispersal denoting that the dispersal strategy depends on environmental conditions. Different dispersal strategies, which either incorporate or neglect this concept, are implemented in a bacterial model and results are compared to data obtained from laboratory experiments with Pseudomonas putida colonies growing on glucose agar. Our results show that, with respect to the condition of resource uptake, the model's correspondence to experimental data is significantly higher for conditional than for unconditional bacterial dispersal. In particular, these results support the hypothesis that bacteria disperse less when resources are abundant. We also show that the dispersal strategy has a considerable impact on model predictions for bacterial degradation of resources: disregarding conditional bacterial dispersal can lead to overestimations when assessing the performance of this ecosystem service.


Assuntos
Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Pseudomonas putida/crescimento & desenvolvimento , Pseudomonas putida/metabolismo , Biodegradação Ambiental , Meio Ambiente , Modelos Biológicos , Poluentes do Solo/metabolismo
11.
PLoS One ; 16(3): e0248757, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33739990

RESUMO

Microinsurance is promoted as a valuable instrument for low-income households to buffer financial losses due to health or climate-related risks. However, apart from direct positive effects, such formal insurance schemes can have unintended side effects when insured households lower their contribution to traditional informal arrangements where risk is shared through private monetary support. Using a stylized agent-based model, we assess impacts of microinsurance on the resilience of those smallholders in a social network who cannot afford this financial instrument. We explicitly include the decision behavior regarding informal transfers. We find that the introduction of formal insurance can have negative side effects even if insured households are willing to contribute to informal risk arrangements. However, when many households are simultaneously affected by a shock, e.g. by droughts or floods, formal insurance is a valuable addition to informal risk-sharing. By explicitly taking into account long-term effects of short-term transfer decisions, our study allows to complement existing empirical research. The model results underline that new insurance programs have to be developed in close alignment with established risk-coping instruments. Only then can they be effective without weakening functioning aspects of informal risk management, which could lead to increased poverty.


Assuntos
Seguro Saúde/economia , Participação no Risco Financeiro/economia , Análise de Sistemas , Orçamentos , Características da Família , Fatores de Tempo
12.
Sci Total Environ ; 769: 144324, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33482551

RESUMO

Meeting ecological and water quality standards in lotic ecosystems is often failed due to multiple stressors. However, disentangling stressor effects and identifying relevant stressor-effect-relationships in complex environmental settings remain major challenges. By combining state-of-the-art methods from ecotoxicology and aquatic ecosystem analysis, we aimed here to disentangle the effects of multiple chemical and non-chemical stressors along a longitudinal land use gradient in a third-order river in Germany. We distinguished and evaluated four dominant stressor categories along this gradient: (1) Hydromorphological alterations: Flow diversity and substrate diversity correlated with the EU-Water Framework Directive based indicators for the quality element macroinvertebrates, which deteriorated at the transition from near-natural reference sites to urban sites. (2) Elevated nutrient levels and eutrophication: Low to moderate nutrient concentrations together with complete canopy cover at the reference sites correlated with low densities of benthic algae (biofilms). We found no more systematic relation of algal density with nutrient concentrations at the downstream sites, suggesting that limiting concentrations are exceeded already at moderate nutrient concentrations and reduced shading by riparian vegetation. (3) Elevated organic matter levels: Wastewater treatment plants (WWTP) and stormwater drainage systems were the primary sources of bioavailable dissolved organic carbon. Consequently, planktonic bacterial production and especially extracellular enzyme activity increased downstream of those effluents showing local peaks. (4) Micropollutants and toxicity-related stress: WWTPs were the predominant source of toxic stress, resulting in a rapid increase of the toxicity for invertebrates and algae with only one order of magnitude below the acute toxic levels. This toxicity correlates negatively with the contribution of invertebrate species being sensitive towards pesticides (SPEARpesticides index), probably contributing to the loss of biodiversity recorded in response to WWTP effluents. Our longitudinal approach highlights the potential of coordinated community efforts in supplementing established monitoring methods to tackle the complex phenomenon of multiple stress.

13.
Ecol Evol ; 9(1): 111-124, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30680100

RESUMO

The distribution of a species along a thermal gradient is commonly approximated by a unimodal response curve, with a characteristic single optimum near the temperature where a species is most likely to be found, and a decreasing probability of occurrence away from the optimum. We aimed at identifying thermal response curves (TRCs) of European freshwater species and evaluating the potential impact of climate warming across species, taxonomic groups, and latitude. We first applied generalized additive models using catchment-scale global data on distribution ranges of 577 freshwater species native to Europe and four different temperature variables (the current annual mean air/water temperature and the maximum air/water temperature of the warmest month) to describe species TRCs. We then classified TRCs into one of eight curve types and identified spatial patterns in thermal responses. Finally, we integrated empirical TRCs and the projected geographic distribution of climate warming to evaluate the effect of rising temperatures on species' distributions. For the different temperature variables, 390-463 of 577 species (67.6%-80.2%) were characterized by a unimodal TRC. The number of species with a unimodal TRC decreased from central toward northern and southern Europe. Warming tolerance (WT = maximum temperature of occurrence-preferred temperature) was higher at higher latitudes. Preferred temperature of many species is already exceeded. Rising temperatures will affect most Mediterranean species. We demonstrated that freshwater species' occurrence probabilities are most frequently unimodal. The impact of the global climate warming on species distributions is species and latitude dependent. Among the studied taxonomic groups, rising temperatures will be most detrimental to fish. Our findings support the efforts of catchment-based freshwater management and conservation in the face of global warming.

14.
Front Microbiol ; 9: 734, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29696013

RESUMO

Bacterial degradation of organic compounds is an important ecosystem function with relevance to, e.g., the cycling of elements or the degradation of organic contaminants. It remains an open question, however, to which extent ecosystems are able to maintain such biodegradation function under recurrent disturbances (functional resistance) and how this is related to the bacterial biomass abundance. In this paper, we use a numerical simulation approach to systematically analyze the dynamic response of a microbial population to recurrent disturbances of different spatial distribution. The spatially explicit model considers microbial degradation, growth, dispersal, and spatial networks that facilitate bacterial dispersal mimicking effects of mycelial networks in nature. We find: (i) There is a certain capacity for high resistance of biodegradation performance to recurrent disturbances. (ii) If this resistance capacity is exceeded, spatial zones of different biodegradation performance develop, ranging from no or reduced to even increased performance. (iii) Bacterial biomass and biodegradation dynamics respond inversely to the spatial fragmentation of disturbances: overall biodegradation performance improves with increasing fragmentation, but bacterial biomass declines. (iv) Bacterial dispersal networks can enhance functional resistance against recurrent disturbances, mainly by reactivating zones in the core of disturbed areas, even though this leads to an overall reduction of bacterial biomass.

15.
Sci Rep ; 8(1): 9488, 2018 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-29934540

RESUMO

Terrestrial microbial ecosystems are exposed to many types of disturbances varying in their spatial and temporal characteristics. The ability to cope with these disturbances is crucial for maintaining microbial ecosystem functions, especially if disturbances recur regularly. Thus, understanding microbial ecosystem dynamics under recurrent disturbances and identifying drivers of functional stability and thresholds for functional collapse is important. Using a spatially explicit ecological model of bacterial growth, dispersal, and substrate consumption, we simulated spatially heterogeneous recurrent disturbances and investigated the dynamic response of pollutant biodegradation - exemplarily for an important ecosystem function. We found that thresholds for functional collapse are controlled by the combination of disturbance frequency and spatial configuration (spatiotemporal disturbance regime). For rare disturbances, the occurrence of functional collapse is promoted by low spatial disturbance fragmentation. For frequent disturbances, functional collapse is almost inevitable. Moreover, the relevance of bacterial growth and dispersal for functional stability also depends on the spatiotemporal disturbance regime. Under disturbance regimes with moderate severity, microbial properties can strongly affect functional stability and shift the threshold for functional collapse. Similarly, networks facilitating bacterial dispersal can delay functional collapse. Consequently, measures to enhance or sustain bacterial growth/dispersal are promising strategies to prevent functional collapses under moderate disturbance regimes.


Assuntos
Ecossistema , Microbiologia , Análise Espaço-Temporal , Risco
16.
Ecol Appl ; 17(7): 1857-75, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17974327

RESUMO

It is widely accepted that successful grazing management strategies in semiarid ecosystems need to be adapted to the highly temporal and spatially heterogeneous forage production. Nevertheless, a full understanding of the key factors and processes for sustainable adaptive management has yet to be reached. The investigation of existing, successful range management systems by simulation models may help to derive general understanding and basic principles. The semi-nomadic Himba in northern Namibia applied a sophisticated management system until the mid-1990s which combined season-dependent pasture use (resulting in rainy-season pastures and dry-season pastures), preservation of reserves for drought and sanctions for rule breaking. A stochastic ecological simulation model has been developed here which represents the main aspects of this management system. With this model we analyze (1) which components of the traditional Himba strategy are essential for sustainability and (2) what happens to the state of the rangeland system under socioeconomic changes. This study shows that temporally and spatially heterogeneous pasture use yields higher productivity and quality of a pasture area than the pressure of homogeneous permanent grazing. Two aspects are of importance: (1) intra-annual heterogeneous use (resting of the dry-season pastures during the rainy season) and (2) interannual heterogeneous use (spatial extension of grazing in years of drought). This management system leads to an effective build-up and use of a buffer in the system: the reserve biomass (the non-photosynthetic reserve organs of the plants), an indicator for grazing and management history. Analyzing purchase as one form of socioeconomic change, we demonstrate that easier market access to purchase livestock may lead to a decline in vegetation quality. However, cattle production increases as long as rest periods on parts of the pasture during the rainy season are granted. Methodologically, we emphasize that simulation models offer an excellent framework for analyzing and depicting basic principles in sustainable range management derived from local knowledge. They provide the opportunity of testing whether these basic principles are also valid under different ecological and socioeconomic settings.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Modelos Teóricos , Animais , Bovinos , Humanos , Conhecimento , Namíbia , Poaceae , Chuva , Migrantes
17.
FEMS Microbiol Ecol ; 93(1)2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27798064

RESUMO

In times of global change and intensified resource exploitation, advanced knowledge of ecophysiological processes in natural and engineered systems driven by complex microbial communities is crucial for both safeguarding environmental processes and optimising rational control of biotechnological processes. To gain such knowledge, high-throughput molecular techniques are routinely employed to investigate microbial community composition and dynamics within a wide range of natural or engineered environments. However, for molecular dataset analyses no consensus about a generally applicable alpha diversity concept and no appropriate benchmarking of corresponding statistical indices exist yet. To overcome this, we listed criteria for the appropriateness of an index for such analyses and systematically scrutinised commonly employed ecological indices describing diversity, evenness and richness based on artificial and real molecular datasets. We identified appropriate indices warranting interstudy comparability and intuitive interpretability. The unified diversity concept based on 'effective numbers of types' provides the mathematical framework for describing community composition. Additionally, the Bray-Curtis dissimilarity as a beta-diversity index was found to reflect compositional changes. The employed statistical procedure is presented comprising commented R-scripts and example datasets for user-friendly trial application.


Assuntos
Bactérias/isolamento & purificação , Biodiversidade , Bactérias/classificação , Bactérias/genética , Interpretação Estatística de Dados , Bases de Dados Genéticas , Ecologia , Ecossistema
18.
Nat Commun ; 8: 15472, 2017 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-28589950

RESUMO

Fungal-bacterial interactions are highly diverse and contribute to many ecosystem processes. Their emergence under common environmental stress scenarios however, remains elusive. Here we use a synthetic microbial ecosystem based on the germination of Bacillus subtilis spores to examine whether fungal and fungal-like (oomycete) mycelia reduce bacterial water and nutrient stress in an otherwise dry and nutrient-poor microhabitat. We find that the presence of mycelia enables the germination and subsequent growth of bacterial spores near the hyphae. Using a combination of time of flight- and nanoscale secondary ion mass spectrometry (ToF- and nanoSIMS) coupled with stable isotope labelling, we link spore germination to hyphal transfer of water, carbon and nitrogen. Our study provides direct experimental evidence for the stimulation of bacterial activity by mycelial supply of scarce resources in dry and nutrient-free environments. We propose that mycelia may stimulate bacterial activity and thus contribute to sustaining ecosystem functioning in stressed habitats.


Assuntos
Bacillus subtilis/fisiologia , Ecossistema , Micélio/fisiologia , Água/metabolismo , Bacillus subtilis/citologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Basidiomycota/fisiologia , Carbono/farmacologia , Fusarium/fisiologia , Isótopos , Micélio/efeitos dos fármacos , Nitrogênio/farmacologia , Pythium/fisiologia , Espectrometria de Massa de Íon Secundário , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/crescimento & desenvolvimento
19.
Ecol Lett ; 9(9): 1049-60, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16925654

RESUMO

Although the aim of conservation planning is the persistence of biodiversity, current methods trade-off ecological realism at a species level in favour of including multiple species and landscape features. For conservation planning to be relevant, the impact of landscape configuration on population processes and the viability of species needs to be considered. We present a novel method for selecting reserve systems that maximize persistence across multiple species, subject to a conservation budget. We use a spatially explicit metapopulation model to estimate extinction risk, a function of the ecology of the species and the amount, quality and configuration of habitat. We compare our new method with more traditional, area-based reserve selection methods, using a ten-species case study, and find that the expected loss of species is reduced 20-fold. Unlike previous methods, we avoid designating arbitrary weightings between reserve size and configuration; rather, our method is based on population processes and is grounded in ecological theory.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Modelos Teóricos , Animais , Conservação dos Recursos Naturais/economia , Controle de Custos , Meio Ambiente , Previsões
20.
PLoS One ; 11(4): e0153862, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27082742

RESUMO

Meeting the world's growing energy demand through bioenergy production involves extensive land-use change which could have severe environmental and social impacts. Second generation bioenergy feedstocks offer a possible solution to this problem. They have the potential to reduce land-use conflicts between food and bioenergy production as they can be grown on low quality land not suitable for food production. However, a comprehensive impact assessment that considers multiple ecosystem services (ESS) and biodiversity is needed to identify the environmentally best feedstock option, as trade-offs are inherent. In this study, we simulate the spatial distribution of short rotation coppices (SRCs) in the landscape of the Mulde watershed in Central Germany by modeling profit-maximizing farmers under different economic and policy-driven scenarios using a spatially explicit economic simulation model. This allows to derive general insights and a mechanistic understanding of regional-scale impacts on multiple ESS in the absence of large-scale implementation. The modeled distribution of SRCs, required to meet the regional demand of combined heat and power (CHP) plants for solid biomass, had little or no effect on the provided ESS. In the policy-driven scenario, placing SRCs on low or high quality soils to provide ecological focus areas, as required within the Common Agricultural Policy in the EU, had little effect on ESS. Only a substantial increase in the SRC production area, beyond the regional demand of CHP plants, had a relevant effect, namely a negative impact on food production as well as a positive impact on biodiversity and regulating ESS. Beneficial impacts occurred for single ESS. However, the number of sites with balanced ESS supply hardly increased due to larger shares of SRCs in the landscape. Regression analyses showed that the occurrence of sites with balanced ESS supply was more strongly driven by biophysical factors than by the SRC share in the landscape. This indicates that SRCs negligibly affect trade-offs between individual ESS. Coupling spatially explicit economic simulation models with environmental and ESS assessment models can contribute to a comprehensive impact assessment of bioenergy feedstocks that have not yet been planted.


Assuntos
Agricultura/métodos , Conservação dos Recursos Naturais/economia , Biodiversidade , Biocombustíveis/provisão & distribuição , Biomassa , Simulação por Computador , Técnicas de Apoio para a Decisão , Ecologia , Ecossistema , Alemanha , Modelos Econômicos , Análise de Regressão , Solo , Análise Espacial
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