Search results for "feature"

Diet and feeding habits of nesting and non-nesting ravens (Corvus corax) on a Mediterranean island (Vulcano, Eolian archipelago)

2003

The almost complete absence of information on the trophic ecology of Corvus corax for Mediterranean areas prompted the present research on the small island of Vulcano. Focal observations allowed us to survey the population, which is divided into four territorial pairs and one non-nesting flock (mean n = 23.6 ± 16.3). This flock roosted preferentially near a rubbish dump. Ravens on Vulcano proved to be omnivorous and to feed upon a wide range of food items, with the differences in diet found to be more quantitative than qualitative and related to the season and to the social system. The flock birds consumed more vegetable matter, carrion of domestic animals, other organic matter (eggshells, …

Biodiversity impacts by multiple anthropogenic stressors in Mediterranean coastal wetlands

2022

Abstract Mediterranean coastal wetlands are considered biodiversity hot-spots and contain a high number of endemic species. The biodiversity of these ecosystems is endangered by several pressures resulting from agricultural and urban expansion, climate change, and the alteration of their hydrological cycle. In this study we assess the state-of-the-art regarding the impact of several stressor groups on the biodiversity of Mediterranean coastal wetlands (i.e., lagoons, marshes, estuaries). Particularly, we describe the impacts of eutrophication, chemical pollution, invasive species, salinization, and temperature rise, and analyze the existing literature regarding the impact of multiple stress…

Lluvias torrenciales y cambios geomórficos en una pequeña cuenca de montaña : el barranco de la Cuesta de la Vega (Valencia)

2013

In this paper the effects of great magnitude -450 mm.- as well as high continued intensity -> 90 mm. for 3h.- storm-rains have been studied for a small mediterranean drainage basin (Ayora, Valencia). Such rains caused anormal flows -between 11.2 y 38.2 m3/sec/km2- and the reactivation of erosiona! and aggradational processes, especially at flat bottomed valleys with terrace culture, where new channels were formed. Severa! types of deposits and erosiona! phenomena are established; among them valley amplitude, local slopes, culture abandonment (in a positive sense ), and valley floor terracing are pointed out.

Feeding and management techniques to favour summer sheep milk and cheese production in the Mediterranean environment

2015

Sheep milk production in summer can lead to a diversification of milk products and to a more regular product distribution in the market throughout the year. However, in Mediterranean countries small ruminant production cycles are subjected to seasonal variations in forage resources. During summer, a key period for out of season production systems, nutrition plays a fundamental role in regulating the quantity and quality of milk production. In this review, feeding strategies and techniques that could be applied for out of season production in dairy ewes under different Mediterranean conditions are described for intensive, pasture-based and mixed systems. The most common feeding strategies us…

The crisis facing Tunisian drainage tunnels: identification, analysis and evaluation of water heritage in the Mediterranean region

2014

In regions with Mediterranean and steppe climates, the presence of surface water is sporadic, and a unique – but fragile and undervalued – element of water capture for irrigation and human supply is the ‘qanats’, ‘foggaras’, ‘mkoulas’ or water tunnels. The central objective of this project has been the full study of Tunisia's drainage tunnels. The inventory, analysis and heritage evaluation of Tunisia's ‘qanats’ have been possible through the application of a particular methodology during four annual sessions of fieldwork and analysis in the geographic information system (GIS) laboratory. The results have been: the creation of a spatial data and cartography infrastructure for the Tunisian ‘…

Distribution of Brachionus species in Spanish mediterranean wetlands

1987

In this study 200 zooplankton samples were Burjassotcollected (1979–1980), from 57 different wetlands in coastal Mediterranean Spain (CMS) and examined for the occurrence of Brachionus species. Data on 17 separate physical and chemical features of these water bodies were obtained from samples collected at the same time. Ten different Brachionus species were found in these wetlands, but only six occurred frequently enough to allow further examination of their distributional patterns using multivariate discriminant analysis. To separate these species, three analyses were performed using the 17 physical and chemical parameters, or their ratios. Three discriminant functions accounted for 80% or…

Cerro del Hierro, Spain: the largest exposed early Cambrian palaeokarst

2020

AbstractWe study the largest exposed example of an early Cambrian palaeokarst, associated with laterites and developed during rifting of the Ossa–Morena Zone. The lithostratigraphy, biostratigraphy, facies and the genesis reflect episodes of sea-level fall (Cerro del Hierro Regression) related to tectonic events and palaeoclimate. This palaeokarst can be primarily considered as the result of early Cambrian polyphase karstification in an extensional tectonic regime, later modified by Neogene–Quaternary geomorphological processes. The event may correlate with other regressive events of a similar age in Spain, Italy, United Kingdom, South America and Australia. This episode also has local name…

Using topographical attributes to evaluate gully erosion proneness (susceptibility) in two mediterranean basins: advantages and limitations

2015

Empirical multivariate predictive models represent an important tool to estimate gully erosion susceptibility. Topography, lithology, climate, land use and vegetation cover are commonly used as input for these approaches. In this paper, two multivariate predictive models were generated for two gully erosion processes in San Giorgio basin (Italy) and Mula River basin (Spain) using only topographical attributes as independent variables. Initially, nine models (five for San Giorgio and four for Mula) with pixel sizes ranging from 2 to 50 m were generated, and validation statistics were calculated to estimate the optimal pixel size. The best models were selected based on model performance using…

Population trends and habitat selection of threatened marsh passerines in a protected Mediterranean wetland

2021

Mapping temporally-variable exposure to flooding in small Mediterranean basins using land-use indicators

2011

Abstract This article deals with mapping exposure (or external vulnerability) to flood risk in two typical Mediterranean ephemeral streams: the Barranco de Carraixet and the Rambla de Poyo. The floodplains of both streams are within the metropolitan area of the city of Valencia (Spain’s third largest city). Following the Mediterranean model, they are very fertile areas (with intense periurban and highly productive agriculture) which have recently absorbed the great urban expansion of the metropolis. Hydrologically these basins remain dry for most of the year, but become particularly dangerous during flash-flood events. They generate a risk pattern highly dependent on exposure since, in gene…