Changes in the natural dynamics of Nothofagus dombeyi forests: Population modeling with increasing drought frequencies

Molowny-Horas, R., Suarez, M.L., Lloret, F. (2017) Changes in the natural dynamics of Nothofagus dombeyi forests: Population modeling with increasing drought frequencies. Ecosphere. 8: 0-0.
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Doi: 10.1002/ecs2.1708

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SAPFLUXNET: towards a global database of sap flow measurements

(2016) SAPFLUXNET: towards a global database of sap flow measurements. . : -.
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Doi: https://doi.org/10.1093/treephys/tpw110

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Soil food web stability in response to grazing in a semi-arid prairie: The importance of soil textural heterogeneity

Andrés P., Moore J.C., Simpson R.T., Selby G., Cotrufo F., Denef K., Haddix M.L., Shaw E.A., de Tomasel C.M., Molowny-Horas R., Wall D.H. (2016) Soil food web stability in response to grazing in a semi-arid prairie: The importance of soil textural heterogeneity. Soil Biology and Biochemistry. 97: 131-143.
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Doi: 10.1016/j.soilbio.2016.02.014

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Grazing of grasslands by large herbivores is a form of land use intensification that affects not only plant communities but also soil biota and the ecosystem services that it provides. While grassland ecosystem responses to grazing have been extensively studied, few studies have focused on the effects of aboveground herbivores on belowground diversity and functions. In this work, we quantified effects of grazing on the structure, function and dynamic stability of soil food webs. We sampled a long-term grazing manipulation in a semi-arid shortgrass steppe (USA Great Plains) at sites showing contrasting soil textures. Treatments included native steppe plots that have been moderately grazed since 1939 paired with plots totally protected from grazing since 1996. We sampled our plots for soil C and N, and for soil biota, separated microbes and micro- and mesofauna in trophic functional groups and defined trophic relationships. We used models to estimate carbon and nitrogen mineralization, energy flow throughout the food web, interaction strengths between trophic groups at steady-state and, eventually, asymptotic (near-equilibrium or local) stability (Moore and de Ruiter, 2012). Soil food web response to grazing depended on soil texture and organic matter content. In our food webs, most energy flowed through the fungal and bacterial detritus-based channels (sensu Moore and Hunt, 1988). There was a clear asymmetry between the amount of energy flowing through each of the two channels and, the higher this asymmetry, the higher was food web stability. Stability was affected by both grazing and soil properties (increased under grazing in high clay soils with high organic matter content but decreased in less organic loam sandy soils), and positively associated with soil organic matter content. Overall, we found that the carbon flow through the soil food web of the shortgrass steppe is responsive to grazing in ways that altered stability and that structural, functional, and dynamic attributes are sensitive parameters for evaluating soil response to land use under changing scenarios. © 2016 Elsevier Ltd.

Llegeix més

Body size phenology in a regional bee fauna: A temporal extension of Bergmann's rule

Osorio-Canadas, S., Arnan, X., Rodrigo, A., Torné-Noguera, A., Molowny, R., Bosch, J. (2016) Body size phenology in a regional bee fauna: A temporal extension of Bergmann's rule. Ecology Letters. : 0-0.
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Doi: 10.1111/ele.12687

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Synergistic mortality between a neonicotinoid insecticide and an ergosterol-biosynthesis-inhibiting fungicide in three bee species

Sgolastra, F., Medrzycki, P., Bortolotti, L., Renzi, M.T., Tosi, S., Bogo, G., Teper, D., Porrini, C., Molowny-Horas, R., Bosch, J. (2016) Synergistic mortality between a neonicotinoid insecticide and an ergosterol-biosynthesis-inhibiting fungicide in three bee species. Pest Management Science. : 0-0.
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Doi: 10.1002/ps.4449

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Investigating the Use of Multi-Gaussian Nonlinear Regressions to Separate Collembolan Size Classes for Soil Quality Assessment

Marks E.A.N., Molowny-Horas R., Domene X. (2015) Investigating the Use of Multi-Gaussian Nonlinear Regressions to Separate Collembolan Size Classes for Soil Quality Assessment. Water, Air, and Soil Pollution. 226: 0-0.
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Doi: 10.1007/s11270-015-2503-6

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Previous studies with bioindicator organisms have used somatic length distributions, i.e., population structure, to understand the effects of management, environment, or a potential contaminant on populations. We describe a statistical approach to separate somatic length classes of Folsomia candida juveniles as an endpoint for the assessment of changes in population structure. Reproduction-survival bioassays were carried out with five different biochars applied at increasing concentrations. Multi-Gaussian models parameterized juvenile size class cohorts, and the biomass of each size class cohort was estimated. Population structure was modified by both material type as well as concentration. Both biomass and population structure were sensitive to effects not reflected in juvenile number, the classic endpoint. Treatments with more size classes and larger individuals were taken to represent favorable conditions, and less size classes and smaller individuals indicated less favorable conditions. This extension of the standardized test provided additional information about the demography of the population. © 2015 Springer International Publishing Switzerland.

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A multivariate fractional regression approach to modeling land use and cover dynamics in a Mediterranean landscape

Molowny-Horas R., Basnou C., Pino J. (2015) A multivariate fractional regression approach to modeling land use and cover dynamics in a Mediterranean landscape. Computers, Environment and Urban Systems. 54: 47-55.
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Doi: 10.1016/j.compenvurbsys.2015.06.001

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The way landscapes change in time reveal a great deal of information about the interplay between the forces of nature and the impact of human-driven changes in a Mediterranean landscape. To understand the dynamics behind the process of polygon fragmentation in land use and cover vector maps we illustrate the potential of a novel regression methodology to cope with multivariate fractional data.An overlay of two vector-based land cover maps separated by a time interval of several years (1956 and 1993) show polygons that have become fragmented. Those fragments thus form a multivariate fractional bounded data set. An extension of the Papke and Wooldridge (1996) fractional regression estimation to the case of multivariate response variables has been subsequently developed to study the processes of polygon fragmentation between the two land use and cover maps.The methodology has been applied to a representative set of vector maps from the Barcelona province, Spain. Several explanatory variables have been used, among them the land cover type of the most important adjacent 1956 polygon. The results of our study indicate that the dynamics of fragmentation are determined not only by geographical and environmental variables but also by the neighboring landscape. We discuss its potential use when employed with techniques of landscape modeling. © 2015 Elsevier Ltd.

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Using species distribution modelling to disentangle realised versus potential distributions for rare species conservation

Marcer A., Saez L., Molowny-Horas R., Pons X., Pino J. (2013) Using species distribution modelling to disentangle realised versus potential distributions for rare species conservation. Biological Conservation. 166: 221-230.
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Doi: 10.1016/j.biocon.2013.07.001

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Range maps provide important information in species conservation management, specially in the case of rare species of conservation interest. For the vast majority of cases, this information can only be estimated by means of species distribution modelling. When absence data is unavailable, modelled distribution maps represent the spatial variation of the degree of suitability for the species rather than their realised distribution. Although discerning potentially suitable areas for a given species is an important asset in conservation, it is necessary to estimate current distributions in order to preserve current populations. This work explores the use of species distribution modelling (Maxent) for species of conservation interest when their Extent of Occurrence (EOO) is well-known and there is quality occurrence data. In this case, derived binary maps of potentially suitable areas can be obtained and used to assess the conservation and protection status of a given species in combination with the EOO and existing protected area networks. Seven species, which are rare and endemic to the Western Mediterranean, have been used as an example. Valuable information for conservation assessment such as potentially suitable areas, EOO, Areas of Occupancy (AOO) and degree of protection is provided for this set of species. In addition, the existing informal view that among experts these species have range sizes much smaller than their potentially suitable area is confirmed. This could probably be attributed to important but currently unknown predictor variables and to historical phylogeographic factors. © 2013 Elsevier Ltd.

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Uncoupling the effects of seed predation and seed dispersal by granivorous ants on plant population dynamics

Arnan X., Molowny-Horas R., Rodrigo A., Retana J. (2012) Uncoupling the effects of seed predation and seed dispersal by granivorous ants on plant population dynamics. PLoS ONE. 7: 0-0.
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Doi: 10.1371/journal.pone.0042869

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Secondary seed dispersal is an important plant-animal interaction, which is central to understanding plant population and community dynamics. Very little information is still available on the effects of dispersal on plant demography and, particularly, for ant-seed dispersal interactions. As many other interactions, seed dispersal by animals involves costs (seed predation) and benefits (seed dispersal), the balance of which determines the outcome of the interaction. Separate quantification of each of them is essential in order to understand the effects of this interaction. To address this issue, we have successfully separated and analyzed the costs and benefits of seed dispersal by seed-harvesting ants on the plant population dynamics of three shrub species with different traits. To that aim a stochastic, spatially-explicit individually-based simulation model has been implemented based on actual data sets. The results from our simulation model agree with theoretical models of plant response dependent on seed dispersal, for one plant species, and ant-mediated seed predation, for another one. In these cases, model predictions were close to the observed values at field. Nonetheless, these ecological processes did not affect in anyway a third species, for which the model predictions were far from the observed values. This indicates that the balance between costs and benefits associated to secondary seed dispersal is clearly related to specific traits. This study is one of the first works that analyze tradeoffs of secondary seed dispersal on plant population dynamics, by disentangling the effects of related costs and benefits. We suggest analyzing the effects of interactions on population dynamics as opposed to merely analyzing the partners and their interaction strength. © 2012 Arnan et al.

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Els COVs al Montseny: entre l'smog urbà i la biogeneració.

Seco R, Peñuelas J, Filella I, Llusià J, Molowny-Horas R (2012). Els COVs al Montseny: entre l'smog urbà i la biogeneració. UABdivulga 03/2012.

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