Notas corológicas sobre el Sistema Ibérico Central (provincia de Guadalajara), I

Se presentan nuevas localidades en la provincia de Guadalajara para un conjunto de 40 taxones de plantas vasculares. Entre estas caben destacar el limite meridional en el area de distribution de Erica vagans L. Se indican nuevas poblaciones de especies escasamente representadas en este tramo del Sistema Iberico, entre ellas Ranunculus ophioglossifolius Vill., Rosa villosa L., Geranium collinum Stephan ex Willd., Pulsatilla rubra Delarbre o Lathyrus pannonicus subsp. longestipulatus M. Lainz. Palabras clave: flora, plantas vasculares, corologia, Sistema Iberico, Guadalajara, Espana

Notas corológicas sobre el Sistema Ibérico (provincia de Guadalajara)II

Se presentan nuevas localidades en la provincia de Guadalajara para un conjunto de 33 táxones de plantas vasculares. Entre éstas caben destacar los primeros registros provinciales de plantas como Celtica gigantea (Link) Vázquez & Barkworth, Gagea bohemica subsp. saxatilis (Mert. & W.D.J. Koch) Asch. & Graebn., Gagea reverchonii Degen. y Peucedanum carvifolia Crantz ex Vill., novedad en la comunidad autónoma de Castilla-La Mancha. Palabras clave: flora, plantas vasculares, corología, Sistema Ibérico, Guadalajara, España

Vegetation and fire history since the last glacial maximum in an inland area of the western Mediterranean Basin (Northern Iberian Plateau, NW Spain)

We reconstructed vegetation responses to climate oscillations, fire and human activities since the last glacial maximum in inland NW Iberia, where previous paleoecological research is scarce. Extremely sparse and open vegetation composed of steppic grasslands and heathlands with scattered pioneer trees suggests very cold and dry conditions during the Oldest Dryas, unsuitable for tree survival in the surroundings of the study site. Slight woodland expansion during the Bolling/Allerod was interrupted by the Younger Dryas cooling. Pinewoods dominated for most of the early Holocene, when a marked increase in fire activity occurred. Deciduous trees expanded later reaching their maximum representation during the mid-Holocene. Enhanced fire activity and the presence of coprophilous fungi around 6400-6000 cal yr BP suggest an early human occupation around the site. However, extensive deforestation only started at 4500 calyrBP, when fire was used to clear the tree canopy. Final replacement of woodlands with heathlands, grasslands and cereal crops occurred from 2700 cal yr BP onwards due to land-use intensification. Our paleoecological record can help efforts aimed at restoring the natural vegetation by indicating which communities were dominant at the onset of heavy human impact, thus promoting the recovery of currently rare oak and alder stands

Simethis mattiazzi (Vandelli) Saccardo [(= S. planifolia (G.) Gren.], redescubierta para la flora de Castilla-La Mancha (España)

Durante los trabajos de seguimiento de la regeneración natural en la zona del Rodenal de Guadalajara afectada por las llamas en el verano de 2005, se localizó una numerosa población de Simethis mattiazzi (Vandelli) Saccardo

Effects of radio-frequency fields on bacterial cell membranes and nematode temperature-sensitive mutants

Membrane-related bioeffects have been reported in response to both radio-frequency (RF) and extremely low-frequency (ELF) electromagnetic fields (EMFs), particularly in neural cells. We have tested whether RF fields might cause inner membrane leakage in ML35 E. coli cells, which express β-galactosidase (lacZ) constitutively, but lack the lacY permease required for substrate entry. The activity of lacZ (indicating substrate leakage through the inner cell membrane) was increased only slightly by RF exposure (1 GHz, 0.5 W) over 45 min. Since lacZ activity showed no further increase with a longer exposure time of 90 min, this suggests that membrane permeability per se is not significantly affected by RF fields, and that slight heating (≤ 0.1°C) could account for this small difference. Temperature-sensitive (ts) mutants of the nematode, Caenorhabditis elegans, are wild-type at 15°C but develop the mutant phenotype at 25°C; an intermediate temperature of 21°C results in a reproducible mixture of both phenotypes. For two ts mutants affecting transmembrane receptors (TRA-2 and GLP-1), RF exposure for 24 h during the thermocritical phase strongly shifts the phenotype mix at 21°C towards the mutant end of the spectrum. For ts mutants affecting nuclear proteins, such phenotype shifts appear smaller (PHA-1) or non-significant (LIN-39), apparently confirming suggestions that RF power is dissipated mainly in the plasma membrane of cells. However, these phenotype shifts are no longer seen when microwave treatment is applied at 21°C in a modified exposure apparatus that minimises the temperature difference between sham and exposed conditions. Like other biological effects attributed to microwaves in the C. elegans system, phenotype shifts in ts mutants appear to be an artefact caused by very slight heating

The past distribution of pinus nigra arnold in northern iberia. Contribution from its macroremains.

The presence of Pinus nigra in central Spain, where its natural populations are very rare, has led to different interpretations of the current vegetation dynamics. Complementary to the available palynological evidence, macroremains provide local information of high taxonomic resolution that helps to reconstruct the palaeobiogeography of a given species. Here we present new macrofossil data from Tubilla del Lago, a small palaeolake located at the eastern part of the northern Iberian Meseta. We identified 17 wood samples and 71 cones on the basis of their wood anatomy and morphology, respectively. S ome of the fossil samples were radiocarbon dated (~4.230-3210 years cal BP). The results demonstrate the Holocene presence of P. nigra in the study area, where it is currently extinct. This evidence, together with other published palaeobotanical studies, indicates that the forests dominated by P. nigra must have had a larger importance on the landscape prior to the anthropogenic influence on the northern Iberian Meseta

Late Holocene vegetation dynamics in response to human activities in the Teleno Mountain Range (NW Iberia)

Teleno Mountains are a good area to address these questions. Today are almost completely deforested, and it is commonly assumed that Romans were the culture responsible of this situation, as they developed important mining activities all over this mountains. Our main aim has been to track human impact on the landscape of this Iberian mountainous area along the second half of the Holocene and confirm the role of Roman culture in this process. For this purpose, we have obtained a new palaeoecological record from the Teleno Mountain

Conservación del elemento boreo-alpino del sistema central: Microrreserva de los circos de Cerezuelo y Buitrera

El entorno del Pico del Lobo es uno de los enclaves del Sistema Central con una mayor diversidad de taxones eurosiberianos y boreo-alpinos, presentando además diversos hábitats de carácter atlántico y orófilo bien conservados. La presencia en la zona de dos especies del Catálogo de Flora Protegida regional,Swertia perennis L. y Huperzia selago (L.) Bernh. ex Schrank & Mart .subsp. selago y en el marco del Decreto 63/2007 de la Junta de Castilla y León, se propone la creación de la presente Microrreserva de Flora