Aboveground Biomass Patterns of Dominant Spartina Species and Their Relationship with Selected Abiotic Variables in Argentinean SW Atlantic Marshes     

Diana I. Montemayor  Alejandro D. Canepuccia  Jesus Pascual  Oscar O. Iribarne 《Estuaries and Coasts》2014,37(2):411-420

Salt marsh zonation patterns generate different abiotic and biotic conditions that can accentuate species inherent differences in primary production and biomass. In South West Atlantic marshes, there are two Spartina species: Spartina alterniflora in the low intertidal and Spartina densiflora in the high intertidal. These two species are generally found in all marshes but with different dominance: In some marshes, the S. densiflora zone occupies higher extents, and in others, the S. alterniflora zone is the one that prevails. We found through field sampling that, in six studied marshes, there is greater S. densiflora live and total (i.e., dead+live) aboveground biomass (g m^?2) in the marshes dominated by S. densiflora than in the ones dominated by S. alterniflora. Spartina alterniflora had similar aboveground biomass in the six marshes, regardless of the dominance of each species. When comparing the two Spartina species within each marsh, S. densiflora had greater live and total biomass in the marshes it dominates. In the marshes dominated by S. alterniflora, both species had similar live and total biomass. In all marshes, there was greater dead S. densiflora biomass. A multivariate analysis using selected abiotic factors (i.e., salinity, latitude, and tidal amplitude) showed that S. alterniflora aboveground biomass patterns are mainly correlated with salinity, while S. densiflora live biomass is mainly correlated with salinity and latitude, dead biomass with salinity and tidal amplitude, and total biomass with salinity alone. We conclude that in S. densiflora dominated marshes, the main processes of that species zone (i.e., nutrient accumulation) will be accentuated because of its higher biomass. We also conclude that climatic conditions, in combination with specific Spartina biotic and ambient abiotic parameters, can affect marsh ecological functions.  相似文献   

Presence and spatial distribution of emerging contaminants (drugs of abuse) in protected agroecological systems (L’Albufera de Valencia Coastal Wetland, Spain)     

Juan Antonio Pascual Aguilar  Vicente Andreu  Pablo Vázquez  Yolanda Picó 《Environmental Earth Sciences》2014,71(1):31-37

The Mediterranean wetlands are unique in biological diversity and provide multiple benefits, constituting a great water reserve for the planet and producing biomass and nutrients for the trophic chain. However, the increasing human impact and socio-economic development in recent decades have caused important losses in these ecosystems. This work was carried out in the Natural Park of L’Albufera (Valencia, Spain), which includes a coastal lagoon, marshlands, dunes and pinewoods, surrounded by rice fields and orchard in its non-urbanized part. Despite this great ecological value, it suffers impacts derived from the high human and industrial occupation and the hydrological contributions of the connected irrigation systems. The study focused on the development of a combined methodology, based on environmental forensics principles, with the aim of identifying the presence, flow paths and spatial distribution of illicit drugs entering the Natural Park. It is organized around two major procedures: analysis of 16 water samples and application of Geographical Information Systems (GIS) integrating different sources and data formats, as analysis of 14 drugs of abuse by Liquid Chromatography-Mass Spectrometry techniques, and social and environmental data in either GIS layers or tabular digital formats. Results show that, at present, most analyzed drugs have been identified in all sample points. Besides the population distribution pattern, the traditional irrigation system connected to sewage treatment plant (STP) locations is the way by which illicit substances are introduced into the Natural Park waters.  相似文献   

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

César Morales-Molino  Mercedes García-Antón 《Quaternary Research》2014

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 Bølling/Allerød 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 cal yr BP, 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.  相似文献   

Hydrogeochemistry approach to the identification of flow components under the descending limb conditions of a hydrograph (Corbeira stream,Spain)     

Juciene Andrade Figueiredo  Eldemar Albuquerque Menor  Maria Teresa Taboada-Castro  Maria Mercedes Taboada-Castro  Luís Drude Lacerda 《Applied Geochemistry》2012

This paper presents a method based on hydrogeochemical signatures for the identification of flow components, from the descending limb to the baseflow, without the direct support of hydrographs. The proposed model was built using chemical analysis of waters from a small agro-forestry catchment having a temperate climate. The sampling was performed every 15 days at the Corbeira stream outlet, from 2004 to 2008. A statistical approach was used with particulate P/dissolved P (PP/DP) values, resulting in a global histogram, within which mini-Gaussian distributions were highlighted. The mean of each group of highlighted PP/DP values, as well as all other selected analytical parameters, were calculated and plotted in Cartesian diagrams. The results showed the hydrogeochemical signatures of the Corbeira stream in the descending limb to baseflow conditions. Scatterplots of the migration of particulate matter showed linear regressions forming α ≠ 0 to the X-axis, while dissolved compounds showed parallel linearity (α = 0) in relation to the same axis. Deflections in the linear behavior point to significant changes in the chemical concentrations from different types of aqueous inputs. Flow components in the descending limb show distinct ranges along the X-axis: the mean PP/DP values. The ranges varying from 3.3 to 2.0 correspond to its upper phases from 2.0 to 0.9 suggests mixtures between inflows and from 0.9 to 0.3 denote subsurface flow dominance. Finally, PP/DP < 0.3 indicates exclusive baseflow conditions. These intervals are specific to the Corbeira catchment as a consequence of its geographical characteristics and should be numerically different from the proposed method if applied to other catchments. However, this method remains valid for application in other small catchments as the PP/DP ranges in the descending limb are defined by the relative behavior between the linear correlations from the hydrogeochemical concentrations plotted in a Cartesian diagram.  相似文献   

Diffusion of landfill leachate through compacted natural clays containing small amounts of carbonates and sulfates   总被引：1，自引：0，他引：1  

Isabel S. De Soto  Ana I. Ruiz  Carlos Ayora  Rosario García  Mercedes Regadio  Jaime Cuevas 《Applied Geochemistry》2012

  相似文献   

A rootless suture and the loss of the roots of a mountain chain: The Variscan belt of NW Iberia     

José R. Martínez Catalán  Ricardo Arenas  Jacobo Abati  Sonia Sánchez Martínez  Florentino Díaz García  Javier Fernández Suárez  Pablo González Cuadra  Pedro Castiñeiras  Juan Gómez Barreiro  Alejandro Díez Montes  Emilio González Clavijo  Francisco J. Rubio Pascual  Pilar Andonaegui  Teresa E. Jeffries  James E. Alcock  Rubén Díez Fernández  Alicia López Carmona 《Comptes Rendus Geoscience》2009,341(2-3):114-126

Ophiolites of different Paleozoic ages occur in North-West (NW) Iberia in a rootless suture representing the remnants of the Rheic Ocean. Associated allochthonous terranes in the hanging- and foot-walls of the suture derive from the former margins, whereas the relative autochthon corresponds to the Paleozoic passive margin of northern Gondwana. The Paleozoic tectonic evolution of this part of the circum-Atlantic region is deduced from the stratigraphical, petrological, structural and metamorphic evolution of the different units and their ages. The tectonic reconstruction covers from Cambro-Ordovician continental rifting and the opening of the Rheic Ocean to its Middle to Upper Devonian closure. Then, the Variscan Laurussia–Gondwana convergence and collision is briefly described, from its onset to the late stages of collapse associated with the demise of the orogenic roots.  相似文献   

Early angiosperm diversification: evidence from southern South America     

Sergio Archangelsky  Viviana Barreda  Mauro G. Passalia  Maria Gandolfo  Mercedes Prámparo  Edgardo Romero  Rubén Cúneo  Alba Zamuner  Ari Iglesias  Magdalena Llorens  Gabriela G. Puebla  Mirta Quattrocchio  Wolfgang Volkheimer 《Cretaceous Research》2009,30(5):1073-1082

In this report, we analyze the angiosperm fossil record (micro- and megafossil) from the central and southern basins of Argentina, southern South America, deposited between the late Barremian (128.3 Ma) to the end of the Coniacian (85.8 Ma). Based on this analysis, three major stages in the evolution of the angiosperms in the southernmost region of South America are established as follows: the late Barremian–Aptian, the latest Aptian-earliest Albian, and the middle Albian- Coniacian. The comparison between our fossil data set and those from Australia, North America, Asia and Europe suggest that the evolution and diversification of the angiosperms at mid and high latitudes in both hemispheres occurred roughly synchronously.  相似文献   

Benthic invertebrate assemblages and functional feeding groups in the Paraná River floodplain (Argentina)     

Florencia Lucila Zilli  Luciana Montalto  Mercedes Rosa Marchese 《Limnologica》2008,38(2):159-171

The benthic invertebrate assemblages and functional feeding groups in different mesohabitats of the Middle Paraná River–floodplain system were analyzed. Benthic invertebrates and bottom sediments were sampled in a secondary channel (center and bank mesohabitats), a temporal marginal fluvial wetland adjacent to the river, an isolated lake and a connected lake during low water level. Cluster analysis of average invertebrate densities based on the Bray Curtis dissimilarity index yielded a group composed by the mesohabitats with higher species richness, the floodplain lakes, banks mesohabitats and the wetland. The center mesohabitat of the main channel characterized by sandy sediments with low organic matter content and the lowest invertebrate densities and species richness was classified separately. Alpha diversity increased from the center mesohabitat (6 taxa) to the adjacent wetland (71 taxa), and were similar between the floodplain lakes (24 and 22 taxa) and the river bank mesohabitat (24 taxa). Gamma and beta diversities (Whittaker index) were 92 and 2.19, respectively. The highest turnover of taxa was between the river and the other mesohabitats and the lowest between floodplain lakes. Detrended correspondence analysis (DCA) showed a clear separation of wetland and banks from other mesohabitats (axis 1 and 2 explained 52.25% variance) explained by shredders and collector-filterers. The other mesohabitats were arranged in a gradient from the main channel mostly related to collector-gatherers to the connected lake and the isolated lake that were mostly characterized by predators and scrapers. The invertebrate assemblage complexity and functional feeding groups composition increased in the lateral dimension, from the center of the main channel to the temporal marginal fluvial wetland due to the influences of the spatial heterogeneity caused by different sources of organic matter inputs.  相似文献   

Tourism versus nature conservation: reconciliation of common interests and objectives——an analysis through Picos de Europa National Park     

Iván López  Mercedes Pardo 《山地科学学报》2018,15(11):2505-2516

Nature tourism and particularly tourism in national parks have acquired significant importance in contemporary societies. Post-Fordist consumers have reevaluated the meanings of ‘nature' and ‘natural spaces' and now avoid standardization to seek singularity. Tourism in national parks is a consequence of this tendency and has both positive and negative aspects. The purpose of this sociological research is to describe the most relevant conflicts in the Picos de Europa National Park(Spain) involving the park's conservation, local economic development,and tourism. Seven in-depth interviews and three focus groups were addressed to key local stakeholders.In this research were identified three chief areas of existing or potential inter-related conflicts and the main actors interacting with them. The first is on population, particularly, the negative consequences of depopulations on the local socio-economic development and the environment. A second source of conflicts identified is caused by the difficult conciliation between commercial exploitation and conservation of the protected natural area. More precisely, this specific form of tourism positively contributes to the economy of local communities whilst problems can arise for the conservation goals of National Parks. Thirdly, in this research is also analyzed the institutional governance and the inter and intra-governmental conflicts as well as with the Park's management body. These findings provide important information for the improved management of tourism and conflicting interests in natural parks.  相似文献   

The Iberian type of volcano-sedimentary massive sulphide deposits   总被引：6，自引：0，他引：6  

R. Sáez  E. Pascual  M. Toscano  G. R. Almodóvar 《Mineralium Deposita》1999,34(5-6):549-570

The Iberian Pyrite Belt, located in the SW Iberian Peninsula, contains many Paleozoic giant and supergiant massive sulphide deposits, including the largest individual massive sulphide bodies on Earth. Total ore reserves exceed 1500 Mt, distributed in eight supergiant deposits (>100 Mt) and a number of other smaller deposits, commonly with associated stockwork mineralizations and footwall alteration haloes. Massive sulphide bodies largely consist of pyrite, with subordinated sphalerite, galena and chalcopyrite and many other minor phases, although substantial differences occur between individual deposits, both in mineral abundance and spatial distribution. These deposits are considered to be volcanogenic, roughly similar to volcanic-hosted massive sulphides (VHMS). However, our major conclusion is that the Iberian type of massive sulphides must be considered as a VHMS sub-type transitional to SHMS. This work is an assessment of the geological, geochemical and metallogenic data available up to date, including a number of new results. The following points are stressed; (a) ore deposits are located in three main geological sectors, with the southern one containing most of the giant and supergiant orebodies, whereas the northern one has mainly small to intermediate-sized deposits; (b) ore deposits differ one from another both in textures and mineral composition; (c) Co and Bi minerals are typical, especially in stockwork zones; (d) colloidal and other primary depositional textures are common in many localities; (e) a close relation has been found between ore deposits and some characteristic sedimentary horizons, such as black shales. In contrast, relationships between massive sulphides and cherts or jaspers remains unclear; (f) footwall hydrothermal alterations show a rough zoning, the inner alteration haloes being characterized in places by a high Co/Ni ratio, as well as by mobility of Zr, Y and REE; (g) ¹⁸O and D values indicate that fluids consist of modified seawater, whereas ³⁴S data strongly suggest the participation of bacterial-reduced sulphur, at least during some stages of the massive sulphide genesis, and (h) lead isotopes suggest a single (or homogeneized) metal source, from both the volcanic piles and the underlying Devonian rocks (PQ Group). It is concluded that, although all these features can be compatible with classical VHMS interpretations, it is necessary to sketch a different model to account for the IPB characteristics. A new proposal is presented, based on an alternative association between massive sulphide deposits and volcanism. We consider that most of the IPB massive orebodies, in particular the giant and supergiant ones, were formed during pauses in volcanic activity, when hydrothermal activity was triggered by the ascent and emplacement of late basic magmas. In these conditions, deposits formed which had magmatic activity as the heat source; however, the depositional environment was not strictly volcanogenic, and many evolutionary stages could have occurred in conditions similar to those in sediment-hosted massive sulphides (SHMS). In addition, the greater thickness of the rock pile affected by hydrothermal circulation would account for the enormous size of many of the deposits. Received: 8 September 1998 / Accepted: 4 January 1999  相似文献