Omar Flores

Vrije Universiteit Amsterdam | VU · Department of Ecological Science

The current state of knowledge on bud dormancy is limited. However, expanding such knowledge is crucial in order to properly model forest responses and feedback to future climate. Recent studies have shown that warming can decrease chilling accumulation and increase dormancy depth, thereby inducing delayed budburst in European beech (Fagus sylvatic...

Wood growth phenology of temperate deciduous trees is less studied than leaf phenology, hindering the understanding of their interaction. In order to describe the variability of wood growth and leaf phenology across locations, species and years, we performed phenological observations of both xylem formation and leaf development in three typical tem...

Responses of terrestrial ecosystems to climate change have been explored in many regions worldwide. While continued drying and warming may alter process rates and deteriorate the state and performance of ecosystems, it could also lead to more fundamental changes in the mechanisms governing ecosystem functioning. Here we argue that climate change wi...

Deciduous seasonal forests (DSFs) have a peculiar floristic composition, with species capable of surviving periods of high water deficit in a year. Our goal was to demonstrate that abiotic filters lead to the assembly of two DSF communities that have high floristic dissimilarity. For this, we characterized the environment of the areas and used the...

Research on wood phenology has mainly focused on reactivation of the cambium in spring. In this study we investigated if summer drought advances cessation of wood formation and if it has any influence on wood structure in late successional forest trees of the temperate zone. The end of xylogenesis was monitored between August and November in stands...

Research on wood phenology has mainly focused on reactivation of the cambium in spring. In this study we investigated if summer drought advances cessation of wood formation and if it has any influence on wood structure in late successional forest trees of the temperate zone. The end of xylogenesis was monitored between August and November in stands...

New knowledge on soil structure highlights its importance for hydrology and soil organic matter (SOM) stabilization, which however remains neglected in many wide used models. We present here a new model, KEYLINK, in which soil structure is integrated with the existing concepts on SOM pools, and elements from food web models, that is, those from dir...

The relatively poor simulation of the below-ground processes is a severe drawback for many ecosystem models, especially when predicting responses to climate change and management. For a meaningful estimation of ecosystem production and the cycling of water, energy, nutrients and carbon, the integration of soil processes and the exchanges at the sur...

The extent to which the increasingly frequent episodes of drought-induced tree decline and mortality could alter key soil biogeochemical cycles is unclear. Understanding this connection between tree decline and mortality and soils is important because forested ecosystems serve as important long-term sinks for carbon (C) and essential nutrients (e.g...

Global change, defined as the set of environmental changes (e.g. climate change and/or land use change) resulting from anthropogenic activities and their impacts on Earth system functioning, is threatening the terrestrial biodiversity conservation and thus the ecosystem services provided by nature. It is therefore of upmost importance to anticipate...

This Handbook of methods aim to provide the different techniques and methodologies to obtain a minimum data set of variables, from soil biodiversity assessment to SOM dynamics, including, isotope analysis, bioturbation assessment and metagenomics. With the knowledge gathered in forthcoming projects and studies, researchers (biogeochemists and soil...

Background The study of biodiversity spatial patterns along ecological gradients can serve to elucidate factors shaping biological community structure and predict ecosystem responses to global change. Ant assemblages are particularly interesting as study cases, because ant species play a key role in many ecosystem processes and have frequently been...

Nestedness indices for dry grassland ant assemblages in surveys from all study areas in central Spain. Guadarrama range (-G2014- year 2014: 18 grasslands, 35 species; -G2015- year 2015: 6 grasslands, 26 species) and Serrota range (-S2015- year 2015: 6 grasslands, 20 species). Indices are Nestedness metric based on Overlap and Decreasing Fill (NODF)...

Relationships between temperature and elevation. Linear regressions between elevation and mean annual (air) temperature (top left, R2 = 94%), maximum (soil) temperature (top right, R2 = 80%), minimum (soil) temperature (bottom left, R2 = 96%), and mean annual rainfall (bottom right, R2 = 91%). Regressions built for Guadarrama 2014 data (n = 18 site...

Multiple-site dissimilarities of beta diversity. Multiple-site dissimilarities accounting for the spatial turnover (βSIM) and the nestedness components (βNES) of beta diversity, and sum of both values (βSOR) for dry grassland ant assemblages in all study areas in central Spain. G2014: Guadarrama range 2014; G2015: Guadarrama range 2015; S2015: Serr...

Temporal validation of the relationship between nestedness and elevation. Generalized additive model (GAM) of nestedness ranks (based on nestedness temperature index) on elevation in ant assemblages from Guadarrama range (central Spain) fit to Guadarrama 2014 data and validated with Guadarrama 2015 data. (TIF)

Ant species occurrences and environmental characteristics of sampling plots. IDPlot: plot identification. Survey: G2014 for Guadarrama range in 2014, G2015 for Guadarrama range in 2015 and S2015 for Serrota range in 2015. For each sampling plot we give the elevation (in m), latitude and longitude (UTM, datum European 1950), mean annual rainfall (Me...

Spatial validation of the relationship between nestedness and elevation. Generalized additive model (GAM) of nestedness ranks (based on nestedness temperature index) on elevation in ant assemblages from Guadarrama range (central Spain) fit to Guadarrama 2014 data and validated with Serrota 2015 data. (TIF)

The study of biodiversity spatial patterns along ecological gradients can serve to elucidate factors shaping biological community structure and predict ecosystem responses to global change. Ant assemblages are particularly interesting as study cases, because ant species play a key role in many ecosystem processes and have frequently been identified...

The number of episodes of forest defoliation and mortality associated with drought events has increased substantially during the last decades, and they are further expected to increase even more given the projected climate change scenarios. These increase in episodes of tree mortality suggest that many tree species worldwide are experiencing their...

Litter quality is crucial for the exchange of carbon and nutrients between aboveground and belowground ecosystem compartments through its effect on litter decomposition. Although the effect of grazing on forest ecosystems has been investigated in various studies, the interactive effect that native ungulates and forest management can have on litter...

Mediterranean holm oak (Quercus ilex L.) forests are suffering extensive forest dieback. This may affect plant-soil interactions and in turn, litter decomposition. Here, we propose a study to investigate which factors (climate, litter quality, and soil microbiota and fauna) affect litter decomposition at different scales, and how forest dieback, th...

Integrar las comunidades del suelo en la teoría ecológica general es uno de los desafíos actuales de la Ecología Terrestre. Las comunidades de organismos del suelo son responsables de la descomposición y el reciclado de nutrientes, procesos esenciales para el funcionamiento de los ecosistemas terrestres y los ciclos biogeoquímicos a escala global....

El patrón de distribución biogeográfica de un conjunto de especies puede ser útil para conocer cómo interactúan entre ellas y con el ambiente, así como para anticipar cómo les afectarán cambios futuros como los climáticos. En concreto, el patrón altitudinal de las comunidades de hormigas en pastizales de la Sierra de Guadarrama permite conocer mejo...