HispaVeg: a new online vegetation plot database for Spain

We describe a new online database, named HispaVeg, which currently holds data from 2663 vegetation plots of Spanish woodlands, scrublands and grasslands. Unlike other similar databases, a detailed description of the structure is stored with the floristic data of each plot (i.e., number and physiognomy of the vertical layers, cover values for each layer).Most of the vegetation plots are large rectangles (400 to 2000 square meters) with an average of 34 species per plot. The survey dates range from 1956 to present, with most of the records between 1964 and 1994. The elevation of the plots ranges from 0 to 2880, with most of the plots between 300 and 1500 m. HispaVeg is freely available to the scientific community. Users can query the online database, view printable reports for each plot and download spreadsheet-like raw data for subsets of vegetation plots.

Soil compaction and vegetation cover in a Scots pine stand at the Mediterranean rangelands

Right development of ROOT SYSTEMS is essential to ensure seedling survival in the initial stages of natural regeneration processes. Soil compaction determines this development both because of its influence on soil T�� & moisture dynamics and for its direct effect on soil mechanical impedance to root growth. All this effects can be assessed as a whole through soil penetration resistance (Soil Strength) measurements. SOIL STRENGTH has been usually evaluated in forest research in connection with severe disturbances derived from heavy machinery works during forest operations. Nevertheless, undisturbed soils are also expected to show different levels of compaction for root development. Organic matter modifies soil structure and so on porosity, compaction and resultant soil resistance to penetration. Its concentration in surface layers is rather related to vegetation cover composition and density. So within forest stands, a relationship is expected to be found between VEGETATION COVER density and compaction measured as resistance to penetration (soil strength)

Small-scale variation of vegetation in a mixed forest understorey is partly controlled by the effect of overstory composition on litter accumulation

We investigated how richness and composition of vascular plant species in the understory of a mixed hardwood forest stand varied with respect to the abundance and composition of the overstory. The stand is in central Spain and represents the southernmost range of distribution of several tree and herbaceous species in Europe. Understory species were identified in 46 quadrats (0.25 m2) where variables litter depth and light availability were measured. In addition, we estimated tree density, basal area, and percent basal area by tree species within 6-m-radius areas around each plot. Species richness and composition were studied using path analysis and scale-dependent geostatistical methods, respectively. We found that the relative abundance of certain trees species in the overstory was more important than total overstory abundance in explaining understory species richness. Richness decreased as soil litter depth increased, and soil litter increased as the relative proportion of Fagus sylvatica in the overstory increased, which accounted for a negative, indirect effect of Fagus sylvatica on richness. Regarding understory species composition, we found that some species distributed preferentially below certain tree species. For example, Melica uniflora was most frequent below Fagus sylvatica and Quercus petraea while the increasing proportion of Q. pyrenaica in the overstory favored the presence of Cruciata glabra, Arenaria montana, Prunus avium, Conopodium bourgaei, Holcus mollis, Stellaria media and Galium aparine in the understory. Overall, these results emphasize the importance of individual tree species in controlling the assemblage and richness of understory species in mixed stands. We conclude that soil litter accumulation is one way through which overstory composition shapes the understory community.

Integrated methodology for assessing the effects of geomorphological river restoration on fish habitat and riparian vegetation

Changes in the geomorphology of rivers have serious repercussions, causing losses in the dynamics and naturalness of their forms, going in many cases, from a type of meandering channel, with constant erosion and sedimentation processes, to a channelized narrow river with rigid and stable margins, where the only possibility of movement occurs in the vertical, causing the only changes in channel geometry occur in the river bed. On the other hand, these changes seriously affect the naturalness of the banks, preventing the development of riparian vegetation and reducing the cross connectivity of the riparian corridor. Common canalizations and disconnections of meanders increase the slope, and therefore speed, resulting in processes of regressive erosion, effect increased as a result of the narrowing of the channel and the concentration of flows. This process of incision may turn the flood plain to be "hung", being completely disconnected from the water table, with important consequences for vegetation. As an example of the effects of these changes, it has been chosen the case of the Arga River The Arga river has been channelized and rectified, as it passes along the meander RamalHondo and Soto Gil (Funes, Navarra). The effects on fish habitat and riparian vegetation by remeandering the Arga River are presented. and Ttwo very contrasting situationsrestoration hypothesis, in terms of geomorphology concerns, have been established to assess the effects these changes have on the habitat of one of the major fish species in the area (Luciobabus graellsii) and on the riparian vegetation. To accomplish this goal, it has been necessary to used the a digital elevation model provided by LIDAR flight, bathymetric data, flow data, as inputs, and a hydraulic simulation model 2D (Infoworks RS). The results obtained not only helped to evaluate the effects of the past alterations of geomorphologic characteristics, but also to predict fish and vegetation habitat responses to this type of changes.

Implementation of a module for risk of ozone impacts assessment to vegetation in the integrated assessment modelling system for the Iberian peninsula. Evaluation for wheat and holm oak

A module to estimate risks of ozone damage to vegetation has been implemented in the Integrated Assessment Modelling system for the Iberian Peninsula. It was applied to compute three different indexes for wheat and Holm oak; daylight AOT40 (cumulative ozone concentration over 40 ppb), cumulative ozone exposure index according to the Directive 2008/50/EC (AOT40-D) and PODY (Phytotoxic Ozone Dose over a given threshold of Y nmol m���2 s���1). The use of these indexes led to remarkable differences in spatial patterns of relative ozone risks on vegetation. Ozone critical levels were exceeded in most of the modelling domain and soil moisture content was found to have a significant impact on the results. According to the outputs of the model, daylight AOT40 constitutes a more conservative index than the AOT40-D. Additionally, flux-based estimations indicate high risk areas in Portugal for both wheat and Holm oak that are not identified by AOT-based methods.

Din��mica vegetal desde el tardiglaciar en la cuenca del Duero: interacciones con clima, fuego e impacto humano

La cuenca del Duero constituye un vasto territorio ib��rico cuyo paisaje se encuentra actualmente muy alterado por la mano del hombre y es pr��cticamente imposible localizar alguna manifestaci��n de su cubierta vegetal natural. Aunque la historia de la vegetaci��n en los sectores central y oriental es relativamente bien conocida, en su mitad occidental los registros paleoecol��gicos estudiados hasta la fecha son pr��cticamente inexistentes. Esto hace que se desconozca la respuesta de la vegetaci��n a las diferentes oscilaciones clim��ticas que se han producido desde el ��ltimo M��ximo Glaciar, cu��l fue el impacto de las diferentes culturas sobre el medio, cu��ndo se produjo una alteraci��n profunda de la vegetaci��n natural y cu��l ha sido la historia de los incendios. Este ��ltimo aspecto, el papel e importancia de los incendios, reviste un especial inter��s en la pen��nsula Ib��rica dada su situaci��n geogr��fica y clim��tica dentro de la cuenca Mediterr��nea, donde el fuego es un factor ecol��gico de primer nivel. Las distintas t��cnicas paleoecol��gicas son las m��s adecuadas para abordar todas estas preguntas. De este modo, los avatares de la vegetaci��n a trav��s del tiempo se han reconstruido mediante el an��lisis pol��nico y de macrof��siles, el impacto humano se ha trazado utilizando indicadores pol��nicos ligados a actividades antr��picas y esporas de hongos copr��filos, estudi��ndose los incendios a partir del registro de part��culas microsc��picas de carb��n. La alta resoluci��n temporal y taxon��mica alcanzada en estos an��lisis, as�� como la amplia superficie abarcada con los yacimientos estudiados, hacen que la informaci��n obtenida sea altamente detallada y complete el conocimiento que se tiene sobre la cuenca del Duero. El Tardiglaciar se registra por primera vez en la Meseta Norte Ib��rica en la secuencia de Ayo�� de Vidriales, donde una vegetaci��n esteparia pr��cticamente desarbolada domina durante los periodos fr��os. Durante el interestadial B��lling/Aller��d la expansi��n forestal (pinos, abedules) fue muy leve y tard��a y fue interrumpida bruscamente por el Dryas Reciente. Al final del Dryas Reciente o al inicio del Holoceno se produjo una acusada y r��pida expansi��n de los bosques. Esta din��mica sugiere que no hubo refugios glaciares importantes en esta zona de la Meseta durante el ���Mystery Interval���, aparentemente el periodo m��s fr��o y seco. Los incendios fueron muy escasos, aumentando de forma muy brusca al inicio del Holoceno por el aumento de biomasa y las condiciones relativamente c��lidas y secas. A partir de los registros de Ayo�� y El Ma��llo se consolida la importancia del gradiente oceanicidad-continentalidad en el Sistema Central y la Meseta Norte, que se manifiesta principalmente en la dominancia m��s prolongada de los pinares hacia el interior. Adem��s, otra de las principales contribuciones de la presente tesis es proporcionar evidencia sobre la sucesi��n de distintos tipos de bosques en el noroeste de la Meseta, precisando el marco temporal en el que suceden. As��, se ha constatado que hubo un m��ximo desarrollo del bosque caducifolio durante el Holoceno medio en Ayo�� de Vidriales y una baja incidencia del fuego que sugieren que el clima fue m��s h��medo que en el Holoceno inicial. El estudio de macrof��siles le��osos ha permitido detectar procesos que con el an��lisis pol��nico habr��an pasado desapercibidos, como la persistencia hasta el Holoceno final de Pinus sylvestris en la sierra del Teleno y la sustituci��n de P. sylvestris por P. pinaster en la sierra de Francia durante el Holoceno inicial. Tambi��n el estudio de los carbones procedentes de los arenales de Tierra de Pinares han proporcionado la prueba definitiva de la naturalidad de los pinares de P. pinaster. El impacto humano se detecta temprano en las secuencias del oeste de la cuenca del Duero, durante el Neol��tico, aunque ha sido mucho m��s acusado desde la Edad del Hierro (ca 2700-2500 a��os cal BP). Para la detecci��n del impacto humano temprano ha sido clave el an��lisis de esporas de hongos copr��filos, cuyo an��lisis fue incorporado en la secuencia de Ayo�� de Vidriales. Una de sus principales consecuencias fue el establecimiento de comunidades de matorral (brezales, piornales) sobre amplias extensiones del occidente de la cuenca del Duero, vinculado al recrudecimiento de los reg��menes de incendios. A pesar de que los incendios han sido ecol��gicamente importantes desde el inicio del Holoceno, los cambios introducidos por el hombre en sus reg��menes sobrepasaron la resiliencia de los bosques originales, lo cual condujo a su sustituci��n sostenida por matorrales. ABSTRACT The Duero Basin constitutes a vast Iberian territory which is currently strongly disturbed due to human activities, so it is very difficult to find any remnant of the natural vegetation. Vegetation history for the eastern and western sectors of the Basin is relatively well-known but, in contrast, there is an almost complete lack of palaeoecological record in the western area. Consequently, there exists a profound ignorance about vegetation responses to the climatic oscillations occurred since the Last Glacial Maximum, the environmental impact of the different cultures, when a severe disturbance of the natural vegetation took place and fire history. The last question, the role and importance of fire, has a special interest in the Iberian Peninsula due to its geographic and climatic framework, the Mediterranean Basin, where fire is a major ecological factor. The diverse palaeoecological techmiques are the most suitable tools to address all these questions. Thus, vegetation shifts through time have been reconstructed using pollen and macrofossil analyses, human impact has been tracked by means of anthropogenic pollen indicators and dung fungal spores, while fire history has been studied from the quantification of microscopic charcoal particles. The high taxonomic and time resolution attained along with the extensive surface covered by the studied sites provide detailed information very useful to complete the knowledge on landscape dynamics in the Duero Basin. The Lateglacial is recorded for the first time in the Northern Iberian Plateau in the sequence from Ayo�� de Vidriales, showing that almost treeless steppic vegetation dominated during the cold periods. Tree expansion (pines, birches) was late and slight during the B��lling/Aller��d interstadial and was sharply interrupted by the Younger Dryas (YD) climatic reversal. By the end of the YD or the onset of the Holocene, a rapid forest expansion occurred. This forest dynamics suggests an absence of important glacial refugia for trees in this area of the Plateau during the Mystery Interval, apparently the coldest and driest period. Fires were fairly rare, increasing abruptly at the beginning of the Holocene due to the relatively warm and dry climate and the accumulation of biomass. The records from Ayo�� and El Ma��llo reinforce the role of the oceanicity-continentality gradient in the vegetation history of the Iberian Central Range and the Iberian Northern Plateau, reflected mainly in the longer dominance of pine forests towards inland areas. Further, another important contribution of this PhD Thesis is providing evidence on the succession of different forest types in the northestern fringe of the Plateau, specifying the chronological framework. A maximum of deciduous forest development and low fire activity have been detected in Ayo�� de Vidriales during the mid-Holocene, suggesting that climate was wetter than in the early Holocene. The study of woody macrofossils has allowed detecting processes which would have remained unnoticed using pollen analysis alone, such as the persistence of Pinus sylvestris until the late Holocene in the Teleno Mountains and the early Holocene replacement of P. sylvestris with P. pinaster in the sierra de Francia range. The study of macroscopic charcoal fragments from palaeosols of the Tierra de Pinares has also provided the definitive proof of naturalness for the P. pinaster stands gorwing over this area at present. Early human impact, during the Neolithic, has been detected in the sequences from the western sector of the Duero Basin, although human disturbance has been more severe from the Iron Age onwards (ca 2700-2500 cal yr BP). The analysis of coprophilous fungi incorporated in the sequence of Ayo�� de Vidriales has played a key role in recognizing that early human impact. One of the main consequences of human disturbance was the establishment of shrubland communities (heaths, brooms) over huge areas of the western Duero Basin, linked to severe and/or frequent fires. Despite fires has been ecologically important since the onset of the Holocene, human-induced changes in fire regimes have exceeded the resilience of original forests leading to a sustained replacement with shrublands.

Holocene vegetation, fire and climate interactions in western Spain: El Ma��llo mire

Interacciones entre la vegetaci��n del Holoceno, el fuego y el clima en el oeste de Espa��a, ejemplo con datos de la turbera del Ma��llo.

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.

More macrofossils are needed to successfully model late-quaternary vegetation

The need of more macrofossils to model late-quaternary vegetation is emphasized in the light of Iberian palaeobotanical data

Nuances matter: How fossil woody remains changed the interpretation of the vegetation in Iberia

Ejemplos de c��mo los macrorrestos ayudan a mejorar la interpretaci��n del paisaje vegetal de la pen��nsula Ib��rica

Negative density dependence and environmental heterogeneity effects on tree ferns across succession in a tropical montane forest.

Although tree ferns are an important component of temperate and tropical forests, very little is known about their ecology. Their peculiar biology (e.g., dispersal by spores and two-phase life cycle) makes it difficult to extrapolate current knowledge on the ecology of other tree species to tree ferns. In this paper, we studied the effects of negative density dependence (NDD) and environmental heterogeneity on populations of two abundant tree fern species, Cyathea caracasana and Alsophila engelii, and how these effects change across a successional gradient. Species patterns harbor information on processes such as competition that can be easily revealed using point pattern analysis techniques. However, its detection may be difficult due to the confounded effects of habitat heterogeneity. Here, we mapped three forest plots along a successional gradient in the montane forests of Southern Ecuador. We employed homogeneous and inhomogeneous K and pair correlation functions to quantify the change in the spatial pattern of different size classes and a case-control design to study associations between juvenile and adult tree ferns. Using spatial estimates of the biomass of four functional tree types (short- and long-lived pioneer, shade- and partial shade-tolerant) as covariates, we fitted heterogeneous Poisson models to the point pattern of juvenile and adult tree ferns and explored the existence of habitat dependencies on these patterns. Our study revealed NDD effects for C. caracasana and strong environmental filtering underlying the pattern of A. engelii. We found that adult and juvenile populations of both species responded differently to habitat heterogeneity and in most cases this heterogeneity was associated with the spatial distribution of biomass of the four functional tree types. These findings show the effectiveness of factoring out environmental heterogeneity to avoid confounding factors when studying NDD and demonstrate the usefulness of covariate maps derived from mapped communities.

Application of Vegetation Indices to Estimate Acorn Production at Iberian

The Iberian pig valued natural resources of the pasture when fattened in mountain. The variability of acorn production is not contained in any line of Spanish agricultural insurance. However, the production of arable pasture is covered by line insurance number 133 for loss of pasture compensation. This scenario is only contemplated for breeding cows and brave bulls, sheep, goats and horses, although pigs are not included. This insurance is established by monitoring ten-day composites Normalized Difference Vegetation Index (NDVI) measured by satellite over treeless pastures, using MODIS TERRA satellite. The aim of this work is to check if we can use a satellite vegetation index to estimate the production of acorns.

Evaluating the quality of riparian forest vegetation: The Riparian Forest Evaluation (RFV) index

Aim of study: This paper presents a novel index, the Riparian Forest Evaluation (RFV) index, for assessing the ecological condition of riparian forests. The status of riparian ecosystems has global importance due to the ecological and social benefits and services they provide. The initiation of the European Water Framework Directive (2000/60/CE) requires the assessment of the hydromorphological quality of natural channels. The Directive describes riparian forests as one of the fundamental components that determine the structure of riverine areas. The RFV index was developed to meet the aim of the Directive and to complement the existing methodologies for the evaluation of riparian forests. Area of study: The RFV index was applied to a wide range of streams and rivers (170 water bodies) inSpain. Materials and methods: The calculation of the RFV index is based on the assessment of both the spatial continuity of the forest (in its three core dimensions: longitudinal, transversal and vertical) and the regeneration capacity of the forest, in a sampling area related to the river hydromorphological pattern. This index enables an evaluation of the quality and degree of alteration of riparian forests. In addition, it helps to determine the scenarios that are necessary to improve the status of riparian forests and to develop processes for restoring their structure and composition. Main results: The results were compared with some previous tools for the assessment of riparian vegetation. The RFV index got the highest average scores in the basins of northernSpain, which suffer lower human influence. The forests in central and southern rivers got worse scores. The bigger differences with other tools were found in complex and partially altered streams and rivers. Research highlights: The study showed the index���s applicability under diverse hydromorphological and ecological conditions and the main advantages of its application. The utilization of the index allows a better understanding of the status of riparian forests, and enhances improvements in the conservation and management of riparian areas.

Soil aggregate geometry: Measurements and morphology

Aggregates provide physical microenvironments for microorganisms, the vital actors of soil systems, and thus play a major role as both, an arena and a product of soil carbon stabilization and dynamics. The surface of an aggregate is what enables exchange of the materials and air and water fluxes between aggregate exterior and interior regions. We made use of 3D images from X-ray CT of aggregates and mathematical morphology to provide an exhaustive quantitative description of soil aggregate morphology that includes both intra-aggregate pore space structure and aggregate surface features. First, the evolution of Minkowski functionals (i.e. volume, boundary surface, curvature and connectivity) for successive dilations of the solid part of aggregates was investigated to quantify its 3D geometrical features. Second, the inner pore space was considered as the object of interest. We devised procedures (a) to define the ends of the accessible pores that are connected to the aggregate surface and (b) to separate accessible and inaccessible porosity. Geometrical Minkowski functionals of the intra-aggregate pore space provide the exhaustive characterization of the inner structure of the aggregates. Aggregates collected from two different soil treatments were analyzed to explore the utility of these morphological tools in capturing the impact on their morphology of two different soil managements, i.e. conventional tillage management, and native succession vegetation treatment. The quantitative tools of mathematical morphology distinguished differences in patterns of aggregate structure associated to the different soil managements.