Search results for " Ecosystem"
showing 10 items of 633 documents
The role of fish life histories in allometrically scaled food‐web dynamics
2019
Body size determines key ecological and evolutionary processes of organisms. Therefore, organisms undergo extensive shifts in resources, competitors, and predators as they grow in body size. While empirical and theoretical evidence show that these size‐dependent ontogenetic shifts vastly influence the structure and dynamics of populations, theory on how those ontogenetic shifts affect the structure and dynamics of ecological networks is still virtually absent. Here, we expand the Allometric Trophic Network (ATN) theory in the context of aquatic food webs to incorporate size‐structure in the population dynamics of fish species. We do this by modifying a food web generating algorithm, the nic…
Bitterling Populations in The Sighisoara-Târnava Mare Natura 2000 Site ‒ A Support System for Management Decisions
2016
Abstract The predominant threats to the Bitterling populations in the Sighisoara-Târnava Mare Natura 2000 site are the hydro technical modifications of the river channels, organic contamination and illegal fishing. ADONIS:CE is applied commonly for business processes modelling, however, in this study case was applied in an ecology/biology sphere of interest. The authors acquired a Bitterling model which contained all of the identified habitat species’ necessities, the specific indicators that give good preservation status and the present pressures and threats. The keeping of the riverbed morphodynamics is especially necessary - the meanders existence is significant for the aquatic mollusc s…
Carbon metabolic rates and GHG emissions in different wetland types of the Ebro Delta
2020
Deltaic wetlands are highly productive ecosystems, which characteristically can act as C-sinks. However, they are among the most threatened ecosystems, being very vulnerable to global change, and require special attention towards its conservation. Knowing their climate change mitigating potential, conservation measures should also be oriented with a climatic approach, to strengthen their regulatory services. In this work we studied the carbon biogeochemistry and the specific relevance of certain microbial guilds on carbon metabolisms of the three main types of deltaic wetlands located in the Ebro Delta, north-eastern Spain, as well as how they deal with human pressures and climate change ef…
Thirty years unmanaged green roofs: Ecological research and design implications
2016
Abstract The variations in species composition and assemblage of unmanaged simple-intensive green roofs in Hannover, Germany, were investigated over a thirty year period, in order to assess the persistence of the initial seed mixture and to evaluate floristic changes. The roofs were greened in 1985 with soil-based turf rolls sown with a mixture of five grasses (Festuca rubra, Festuca ovina, Agrostis capillaris, Lolium perenne and Poa pratensis). Three sets of 120 phytosociological releves, sampled in 1987, 1999 and 2014, have been compared to assess: (1) nestedness vs spatial turnover, (2) functional diversity and (3) the importance of vegetation dynamics on green roof performance and desig…
Does an ant-dispersed plant, Viola reichenbachiana, suffer from reduced seed dispersal under inundation disturbances?
2008
Many plant species use ants as seed dispersers. This dispersal mode is considered to be susceptible to disturbances, but the effect of natural, small-scale disturbances is still unknown. We investigated how small-scale disturbances due to inundation affect seed dispersal in Viola reichenbachiana, a dominant myrmecochorous herb in riparian forests. Inundation disturbances were high in depressions and low on hillocks of the forest floor. We found that V reichenbachiana was similarly abundant at highly and less disturbed sites, contrary to other, non ant-dispersed species. We also found that the motivation of ants to disperse seeds was higher at highly disturbed sites. Nevertheless, the number…
Volcanic CO2 seep geochemistry and use in understanding ocean acidification
2020
AbstractOcean acidification is one of the most dramatic effects of the massive atmospheric release of anthropogenic carbon dioxide (CO2) that has occurred since the Industrial Revolution, although its effects on marine ecosystems are not well understood. Submarine volcanic hydrothermal fields have geochemical conditions that provide opportunities to characterise the effects of elevated levels of seawater CO2 on marine life in the field. Here, we review the geochemical aspects of shallow marine CO2-rich seeps worldwide, focusing on both gas composition and water chemistry. We then describe the geochemical effects of volcanic CO2 seepage on the overlying seawater column. We also present new g…
Temporal and spatial patterns of trawl fishing activities in the Adriatic Sea (Central Mediterranean Sea, GSA17)
2020
Abstract Trawl fishing activities have occurred for centuries on large spatial scale in the entire Mediterranean Sea, and today they are considered as one of the main and widespread causes of anthropogenic disturbance and habitat alteration in the marine environment. In order to delineate when, where and how marine ecosystems have been perturbed and to implement ecosystem-based management strategies, the identification and investigation of the spatial and temporal distribution of fishing effort and the fleet dynamics play a key role. In this context, Geospatial Technologies such as the Automatic Identification System (AIS) could represent a useful tool. The aim of the present work is to rec…
Reducing the data-deficiency of threatened European habitats: Spatial variation of sabellariid worm reefs and associated fauna in the Sicily Channel,…
2017
Biogenic reefs, such as those produced by tube-dwelling polychaetes of the genus Sabellaria, are valuable marine habitats which are a focus of protection according to European legislation. The achievement of this goal is potentially hindered by the lack of essential empirical data, especially in the Mediterranean Sea. This study addresses some of the current knowledge gaps by quantifying and comparing multi-scale patterns of abundance and distribution of two habitat-forming species (Sabellaria alveolata and S. spinulosa) and their associated fauna along 190 km of coast on the Italian side of the Sicily Channel. While the abundance of the two sabellariids and the total number of associated t…
Descriptors of Posidonia oceanica meadows: Use and application
2005
This work benefited partly from the financial support of the European program ΓNTERREG IIIA Corsica, Sardinia. Tuscany
Salinity and periodic inundation controls on the soil-plant-atmosphere continuum of gray mangroves
2017
Salinity and periodic inundation are both known to have a major role in shaping the ecohydrology of mangroves through their controls on water uptake, photosynthesis, stomatal conductance, gas-exchanges and nutrient availability. Salinity, in particular, can be considered one of the main abiotic regulating factors for halophytes and salt tolerant species, due to its influence on water use patterns and growth rate. Ecohydrological literature has rarely focused on the effects of salinity on plant transpiration, based on the fact that the terrestrial plants mostly thrive in low saline, unsaturated soils where the role of osmotic potential can be considered negligible. However, the effect of sal…