Xavier Font

Coarse-scale plant species richness in relation to environmental heterogeneity

Abstract We test to what extent mean environmental conditions and environmental heterogeneity are related to species richness in a regular geographical grid system (UTM) of 10 km × 10 km in the NE Iberian Peninsula (i.e. Catalonia, ca. 31900 km2). Species richness of each UTM quadrat was estimated by compiling a large database (more than a million records) from bibliographic references and atlases. Mean environmental conditions of each quadrat were derived from climatic maps. Environmental heterogeneity was estimated from the diversity of geological substrates and climatic classes in each quadrat. The increase in effective (real) area due to topographic complexity was also considered (derived from the digital elevation model). The statistical analysis was performed by a weighted analysis of deviance assuming a negative binomial error distribution. The results suggest that species richness in the study area is a function of both within-quadrat heterogeneity (specifically, effective area, heterogeneity of geological substrates, heterogeneity of January temperature) and mean environmental conditions (mean annual temperature, Thornthwaite moisture index and aspect). All these parameters showed a positive relationship with species richness. Quadrat heterogeneity accounted for ca. 2/3 of the explained deviance, suggesting the importance of environmental heterogeneity when using a geographical grid system. The study fits well with earlier results on the importance of climatic parameters on plant species richness and provides one of the few rigorous, quantitative, coarse-scale studies testing environmental heterogeneity in plant species richness.

Widespread plant species: natives versus aliens in our changing world

Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments.

Geochemical mercury survey in the Azogue Valley (Betic area, SE Spain)

Abstract The old mining site in the Azogue Valley (Almeria, Spain) was exploited in the 19th century for mercury and antimony. This mineralisation is hosted in metamorphosed Permo-Triassic rocks and shows no spatial relationship with regional volcanism. The metallogenetic characteristics suggest the presence of an epithermal deposit as much as 1 km in length, with high Hg and Sb values. These values, together with high Ag, Au, As and Ba contents, suggest similarities to `hot spring-type epithermal mineralisation. An Hg vapour and soil survey yielded Hg haloes which identified the old mining zone, outlining the exploited veins and marking enrichment zones at fault–vein intersections. The geochemistry of Hg-vapour was particularly successful in delineating the epithermal deposit.

Assessing species diagnostic value in large data sets: A comparison between phi-coefficient and Ochiai index

Abstract Question: Diagnostic species are useful tools for the identification and ecological interpretation of community types. Vegetation databases facilitate the computation of diagnostic values of regional validity, but it is essential to understand the behaviour of fidelity measures in large data sets. Methods: We focused our study on the phi-coefficient (Φ) of association and its limit value, the Ochiai index. The northeast Spanish relevé database was stratified using an arbitrary distance threshold in species composition. Diagnostic species analysis was undertaken using three methods of context selection: I. within a syntaxon of higher rank; II. including relevés with similar composition to that of the target unit; III. using the entire stratified database. Species diagnostic values were computed as well as bootstrap percentile confidence intervals. Results: Many species deemed as diagnostic by method I have their optima in vegetation types neighbouring the unit chosen as context. In contrast, method II excluded many of these species. Φ-values and confidence intervals were similar to those obtained by the Ochiai indexwhen using a large dataset (method III) but this similarity was greater for low level syntaxa. Conclusions: The diagnostic value of species in a given region is best assessed using the Ochiai index, since it can be split into two interpretable asymmetrical components. We recommend the determination of context-dependent differential species using the Φ-coefficient, and the assessment of species regional diagnostic value by means of a stratification procedure in combination with the Ochiai index. Nomenclature: Bolòs et al. (1990).

Using 3-D structures and their virtual representation as a tool for restoring opencast mines and quarries

An important factor in the restoration studies of quarries and open-cast mines is the ability of generating final restored models of visualisation. These 3-D models are particularly useful for presenting projects, as they can greatly enhance the analysis of different alternatives. A method involving several subroutines for simulation purposes is presented in this paper. The system allows for the simulation of a variety of geological structures, both real and restored. The subroutines facilitate: (1) the automatic integration between the restoration structure and its geotechnical and morphological parameters, (2) the achievement of a uniform slope, and (3) the adjustment of the talus of the restoration structure to the relief. Graphic output in DXF and VRML formats allows for both static and dynamic optimal visualisation. Readers interested in subroutines written in Visual Basic can contact the first author: victor@geo.ub.es.

Trade-offs between seed and leaf size (seed–phytomer–leaf theory): functional glue linking regenerative with life history strategies … and taxonomy with ecology?

Background and AimsnWhile the worldwide leaf economics spectrum (Wright IJ, Reich PB, Westoby M, et al. 2004. The worldwide leaf economics spectrum. Nature : 821-827) defines mineral nutrient relationships in plants, no unifying functional consensus links size attributes. Here, the focus is upon leaf size, a much-studied plant trait that scales positively with habitat quality and components of plant size. The objective is to show that this wide range of relationships is explicable in terms of a seed-phytomer-leaf (SPL) theoretical model defining leaf size in terms of trade-offs involving the size, growth rate and number of the building blocks (phytomers) of which the young shoot is constructed.nnnMethodsnFunctional data for 2400+ species and English and Spanish vegetation surveys were used to explore interrelationships between leaf area, leaf width, canopy height, seed mass and leaf dry matter content (LDMC).nnnKey ResultsnLeaf area was a consistent function of canopy height, LDMC and seed mass. Additionally, size traits are partially uncoupled. First, broad laminas help confer competitive exclusion while morphologically large leaves can, through dissection, be functionally small. Secondly, leaf size scales positively with plant size but many of the largest-leaved species are of medium height with basally supported leaves. Thirdly, photosynthetic stems may represent a functionally viable alternative to small seeds + large leaves in disturbed, fertile habitats and large seeds + small leaves in infertile ones.nnnConclusionsnAlthough key elements defining the juvenile growth phase remain unmeasured, our results broadly support SPL theory in that phytometer and leaf size are a product of the size of the initial shoot meristem (≅xa0seed mass) and the duration and quality of juvenile growth. These allometrically constrained traits combine to confer ecological specialization on individual species. Equally, they appear conservatively expressed within major taxa. Thus, evolutionary canalization sensu Stebbins (Stebbins GL. 1974. Flowering plants: evolution above the species level . Cambridge, MA: Belknap Press) is perhaps associated with both seed and leaf development, and major taxa appear routinely specialized with respect to ecologically important size-related traits.

Multidata set analysis for gold-deposit exploration criteria: application in the Catalonian Coastal Ranges (NE Spain)

Abstract The method developed in the European Union `Midas project for the exploration of gold deposits was applied in the Catalonian Coastal Ranges of NE Spain. The method is based on the combined use of a multidata set compiled from tools that permit the identification of a series of regional characteristics and which are defined as signatures. These signatures are in turn contrasted with the attributes that characterize known gold deposits which allow for the identification of possible gold mineralization. In the present study, the superimposed multidata sets have helped to identify a series of signatures which are characteristic attributes of both turbidite-hosted and granite-associated type deposits.

Metal Mobilization and Zinc-Rich Circumneutral Mine Drainage from the Abandoned Mining Area of Osor (Girona, NE Spain)

AbstractContaminated soil and mine wastes in Spain’s abandoned Osor mining area contain Cd, Co, Pb, Zn, As, Ba, and Sb at levels that exceed Catalonia’s regulatory limits for soils of industrial use. Mine water from the Coral adit, which is the main dewatering system in the Osor area, has circumneutral pH from carbonate and silicate dissolution, and high concentrations of Fe, Mn, Ni, Pb, and Zn. Geochemical modeling showed that smithsonite and hydrozincite were possible solid phases for Zn. The Coral adit is the main source of contaminants to Osor Creek, especially Zn and SO4−2.nZusammenfassungKontaminierte Böden und Bergbaurückstände im stillgelegten Bergbaugebiet Osor in Spanien enthalten Cd, Co, Pb, Zn, As, Ba und Sb in Konzentrationen, die die Katalanischen Grenzwerte für die industrielle Nutzung überschreiten. Das Wasser aus dem Coral-Stollen, dem Hauptentwässerungssystem des Osor-Gebietes, hat einen zirkumneutralen pH infolge Karbonat- und Silikatauflösung und hohe Konzentrationen an Fe, Mn, Ni, Pb und Zn. Geochemische Modellierungen wiesen Smithsonit und Hydrozinkit als mögliche Mineralphasen für Zink aus. Der Coral-Stollen ist die Hauptquelle für die Kontamination des Osor-Baches, insbesondere für Zn und SO4−2.ResumenLos suelos contaminados y los residuos mineros de la zona minera abandonada de Osor (España) contiene Cd, Co, Pb, Zn, As, Ba y Sb a niveles que exceden los límites regulatorios de Cataluña para suelos de uso industrial. El agua de mina desde el socavón Coral, que es el principal sistema de desagüe del area, tiene pH casi neutro debido a la disolución de carbonatos y silicatos y altas concentraciones de Fe, Mn, Ni, Pb y Zn. Mediante modelos geoquímicos se mostró que smithsonita y hidrocincita eran las posibles fases sólidas de Zn. El socavón Coral es la principal fuente de contaminantes, especialmente Zn y SO4−2, para el arroyo Osor.摘要在西班牙已废弃的奥索尔(Osor)矿区,受污染土壤和矿山固废的镉、钴、铅、锌、砷、钡及锑含量已超过西班牙加泰罗尼亚(Catalonia)地区规定的工业用土壤污染界限。科拉尔(Coral)是奥索尔地区的主要疏水矿坑,排出的废水为近中性的碳酸盐和硅酸盐水,含有高浓度的铁、锰、镍、铅和锌。地球化学模拟结果显示,锌可能主要源自固相菱锌矿和水锌矿。科拉尔矿坑是奥索尔河(Osor Creek)各类污染(尤其是锌和硫酸盐)的主要污染源.

Drastic reduction in the potential habitats for alpine and subalpine vegetation in the Pyrenees due to twenty-first-century climate change

Recent climate change is already affecting both ecosystems and the organisms that inhabit them, with mountains and their associated biota being particularly vulnerable. Due to the high conservation value of mountain ecosystems, reliable science-based information is needed to implement additional conservation efforts in order to ensure their future. This paper examines how climate change might impact on the distribution of the main alpine and subalpine vegetation in terms of losses of suitable area in the Oriental Pyrenees. The algorithm of maximum entropy (Maxent) was used to relate current environmental conditions (climate, topography, geological properties) to present data for the studied vegetation units, and time and space projections were subsequently carried out considering climate change predictions for the years 2020, 2050 and 2080. All models predicted rising altitude trends for all studied vegetation units. Moreover, the analysis of future trends under different climate scenarios for 2080 suggests an average loss in potential ranges of 92.3–99.9xa0% for alpine grasslands, 76.8–98.4xa0% for subalpine (and alpine) scrublands and 68.8–96.1xa0% for subalpine forest. The drastic reduction in the potential distribution areas for alpine grasslands, subalpine scrublands and Pinus uncinata forests highlights the potential severity of the effects of climate change on vegetation in the highest regions of the Pyrenees. Thus, alpine grasslands can be expected to become relegated to refuge areas (summit areas), with their current range being taken over by subalpine scrublands. Furthermore, subalpine forest units will probably become displaced and will occupy areas that currently present subalpine scrub vegetation.

Altitudinal species richness patterns of vascular plants in the south-eastern Pyrenees and nearby mountains of Catalonia

Background: Studying how species richness varies with altitude has become an important part of investigations on mechanisms explaining regional-scale plant species diversity. Altitudinal diversity patterns are poorly known in the Pyrenees and elsewhere in the main mountain massifs in Catalonia (north-eastern Iberian Peninsula). Aim: We examine the altitudinal patterns of species richness in the Catalan Pyrenees and compare them with those in other mountains in Catalonia. Altitude patterns of species richness in the Pyrenees are compared for functional and taxonomic groups of vascular plants. Methods: Data on vascular plants were obtained from the Biodiversity Data Bank of Catalonia. We used rarefaction and interpolation to quantify the altitudinal diversity patterns. Results: The interpolated and rarefied richness generally peaked in the lower part of the altitudinal gradient, but with remarkable variation depending on the taxonomic or functional groups considered. Using all species, there was little variation between the different mountains, but the altitude at which richness started to decrease varied between them. Conclusions: The pronounced differences among different taxonomic groups and life-forms indicate a strong phylogenetic and adaptive signal on the altitudinal diversity pattern in the Catalan Pyrenees. The lack of regional differences within Catalonia is probably due to small differences in the intensity of climatic gradients across mountains.