Papers by Cristina Gimeno
Ecosystems, 2008
Soil respiration constitutes the second largest flux of carbon (C) between terrestrial ecosystems... more Soil respiration constitutes the second largest flux of carbon (C) between terrestrial ecosystems and the atmosphere. This study provides a synthesis of soil respiration (R s ) in 20 European grasslands across a climatic transect, including ten meadows, eight pastures and two unmanaged grasslands. Maximum rates of R s (R s max ), R s at a reference soil temperature (10°C; R s 10 ) and annual R s (estimated for 13 sites) ranged from 1.9 to 15.9 lmol CO 2 m -2 s -1 , 0.3 to 5.5 lmol CO 2 m -2 s -1 and 58 to 1988 g C m -2 y -1 , respectively. Values obtained for Central European mountain meadows are amongst the highest so far reported for any type of ecosystem. Across all sites R s max was closely related to R s 10 .
Plant phenological development is orchestrated through subtle changes in photoperiod, temperature... more Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious , there is a need to supplement long-term observations with automated techniques such as those provided by digital repeat photography at high temporal and spatial resolution. We present the first synthesis from a growing observational network of digital cameras installed on towers across Europe above deciduous and evergreen forests, grasslands and crop-lands, where vegetation and atmosphere CO 2 fluxes are measured continuously. Using colour indices from digital images and using piecewise regression analysis of time series, we explored whether key changes in canopy phenology could be detected automatically across different land use types in the network. The piecewise regression approach could capture the start and end of the growing season, in addition to identifying striking changes in colour signals caused by flowering and management practices such as mowing. Exploring the dates of green-up and senescence of deciduous forests extracted by the piecewise regression approach against dates estimated from visual observations, we found that these phe-nological events could be detected adequately (RMSE < 8 and 11 days for leaf out and leaf fall, respectively). We also investigated whether the seasonal patterns of red, green and blue colour fractions derived from digital images could be modelled mechanistically using the PROSAIL model pa-rameterised with information of seasonal changes in canopy leaf area and leaf chlorophyll and carotenoid concentrations. From a model sensitivity analysis we found that variations in colour fractions, and in particular the late spring 'green hump' observed repeatedly in deciduous broadleaf canopies across the network, are essentially dominated by changes in the respective pigment concentrations. Using the model we were able to explain why this spring maximum in green signal is often observed out of phase with the maximum period of canopy photosynthesis in ecosystems across Europe. Coupling such quasi-continuous digital records of canopy colours with co-located CO 2 flux measurements will improve our understanding of how changes in growing season length are likely to shape the capacity of European ecosystems to sequester CO 2 in the future.
Biogeosciences, 2010
Soil respiration (SR) constitutes the largest flux of CO 2 from terrestrial ecosystems to the atm... more Soil respiration (SR) constitutes the largest flux of CO 2 from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SR MAT ), irrespective of the type of ecosystem and biome. This is theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q 10 ). We further show that for seasonally dry sites where annual precipitation (P ) is lower than potential evapotranspiration (PET), annual SR can be predicted from wet season Correspondence to: M. Bahn ([email protected]) SR MAT corrected for a factor related to P /PET. Our finding indicates that it can be sufficient to measure SR MAT for obtaining a well constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution of soil CO 2 emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatial resolution of a major component of the global carbon cycle.
En este trabajo se estudia la flora briológica de 10s principales afloramientos yesíferos de la C... more En este trabajo se estudia la flora briológica de 10s principales afloramientos yesíferos de la Comunidad Valenciana. Se ha elaborado un catálogo de 66 táxones, algunos de ellos poc0 citados hasta ahora en nuestro territorio. Se incluyen datos sobre las características del suelo (CE, pH y concentraciones de Mg+2, Ca+2, Na+, K+).
Orsis, 1998
... Key words: Anthocerotae, checklist, Hepaticae, Musci, Valencia. Orsis 13, 1998 27-41 Lista de... more ... Key words: Anthocerotae, checklist, Hepaticae, Musci, Valencia. Orsis 13, 1998 27-41 Lista de los briófitos de la Comunidad Valenciana (este de España) Felisa Puche Cristina Gimeno José Gabriel Segarra Universitat de València. ...
Journal of Bryology, 2004
Frey & Kürschner is shown to be a distinct taxon that is easily distinguished from the related C.... more Frey & Kürschner is shown to be a distinct taxon that is easily distinguished from the related C. crassinerve. Discovery of two plants of C. laxefilamentosum with sporophytes has permitted the description of the capsule and spore characters for the first time. This species is recorded as new to Europe and to North Africa. The known range of this desert species is now expanded from South-West Asia to North Africa, to the steep loess cliffs along the River Danube, and to the dry S.E. coast of the Iberian Peninsula. Among these regions five localities are reported from northern Serbia, three from central Hungary, S. of the 47° line of latitude, one from Romania, 20 from Spain and six localities have been found in Tunisia. The distribution of C. laxefilamentosum suggests that it had a circum-Tethyan origin. Al-Gifri AN, Kürschner H. 1996. First records of bryophytes from the Hadramout and Abyan Governorate, Southern Yemen. Studies in Arabian bryophytes 20. Nova Hedwigia 62: 137-146. Cano MJ, Guerra J, Ros RM. 1993. A revision of the moss genus Crossidium (Pottiaceae) with the description of the new genus Microcrossidium. Plant Systematics and Evolution 188: 213-235. Corley MFV, Crundwell AC, Düll R, Hill MO, Smith AJE. 1981. Mosses of Europe and the Azores; an annotated list of species, with synonyms from the recent literature. Journal of Bryology 16: 337-356. Delgadillo C. 1975. Taxonomic revision of Aloina, Aloinella and Crossidium (Musci). Bryologist 78: 245-303. Dirkse GM, Bouman AC. 1995. Crossidium (Musci) in the Canary Islands (Spain).
Botanica Complutensis, 2001
Anales del Jardín Botánico de Madrid, 1988
Las instrucciones para publicar en esta sección pueden verse en Anales Jará. Bot. Madrid 42: 231-... more Las instrucciones para publicar en esta sección pueden verse en Anales Jará. Bot. Madrid 42: 231-232.1985. Los signos convencionales empleados son los siguientes: * Antes del nombre del taxon, para indicar nueva cita nacional. * Antes del nombre de la provincia, para indicar nueva cita provincial. + Antes del nombre del taxon, para indicar que no es planta autóctona. + Antes del nombre de la provincia, para indicar que, aunque se trata de una planta autóctona en otras partes del país, no lo es en la provincia citada. « » Encerrando el nombre del taxon, para indicar que una cita anterior debe ser eliminada.
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Papers by Cristina Gimeno