Search results for "ECOSYSTEM"
showing 10 items of 1752 documents
Ten Years of Paleoceanographic Studies at ODP Site 963 (Central Mediterranean Sea)
2014
The geographical location, the shape and the circulation pattern makes the Mediterranean Sea an ideal laboratory to study the interplay between different climatic systems, abrupt climate changes and the response of marine ecosystems. The Ocean Drilling Program Site 963 was drilled in the Northwestern part of the Sicily Channel, the sill that divides the western from the eastern Mediterranean Sea. Numerous papers have been published on Site 963 sediments in the last decade, investigating Mediterranean paleoceanographic themes. Here we offer a synthetic framework of these investigations carried out by sub-centennial resolution. We present the whole sequence of suborbital climatic oscillations…
Exploring the spatial relationship between airborne-derived red and far-red sun-induced fluorescence and process-based GPP estimates in a forest ecos…
2019
International audience; Terrestrial gross primary productivity (GPP) plays an essential role in the global carbon cycle, but the quantification of the spatial and temporal variations in photosynthesis is still largely uncertain. Our work aimed to investigate the potential of remote sensing to provide new insights into plant photosynthesis at a fine spatial resolution. This goal was achieved by exploiting high-resolution images acquired with the FLuorescence EXplorer (FLEX) airborne demonstrator HyPlant. The sensor was flown over a mixed forest, and the images collected were elaborated to obtain two independent indicators of plant photosynthesis. First, maps of sun-induced chlorophyll fluore…
Effects of heavy metals on soil microflora
2000
Elevated concentrations of heavy metals are known to cause disturbances in all living organisms. A reduction in the activity of forest microbes, expressed as decreased carbon and nitrogen mineralisation, may result in a slower rate of litter decomposition and slower nutrient cycling in the whole ecosystem (Baath 1989). In areas severely polluted by heavy metals, this can be seen as an accumulation of undecomposed litter on the forest floor. Thus, in addition to the direct toxicity of heavy metals, the trees may suffer from nutrient deficiency resulting from the decrease in the mineralisation of nutrients from the litter. Heavy metals can also retard litter decomposition processes in less po…
Effectiveness of Entrepreneurial Universities: Experiences and Challenges in Digital Era (A Systemic Approach)
2021
The modern world actively discusses the challenges that will lead to the Fourth Industrial Revolution. As the specialists assume, part of the jobs will be replaced by artificial intelligence. In addition, creation of completely new jobs is expected. As for the jobs that might be maintained in future, skills upgrading will be particularly important. In such a turbulent environment of economic development, universities, and in particular entrepreneurial universities, play a significant role. We think so as these universities have special structures that promote form a university-industry-government triple helix, reskilling and commercialization of new ideas, etc. Due to the above-mentioned fa…
Fragmentation and local disturbance of forests reduce frugivore diversity and fruit removal in Ficus thonningii trees
2008
Clearance, fragmentation, and degradation of tropical forests have resulted in declines of biodiversity. This loss of biodiversity is endangering important ecosystem processes such as seed dispersal. If anthropogenic disturbances affect seed dispersal of keystone plants, effects on tropical ecosystems might be especially pronounced. We studied frugivore assemblages and fruit removal from 25 Ficus thonningii trees in the heavily fragmented and disturbed Kakamega Forest, western Kenya. During 400 observation hours we recorded 36 frugivores visiting F. thonningii trees. We recorded significantly fewer frugivorous species in fragments compared to the main forest and in highly, compared to littl…
Seabird influence on ecological processes in coastal marine ecosystems: An overlooked role? A critical review
2021
Abstract Seabirds are vital, but overlooked, components of coastal marine ecosystems and may connect the marine and terrestrial environment at a global scale, significantly contributing to inter-habitat connectivity and the provision of multiple ecosystem services. Although the ecological and functional role of birds in terrestrial areas, islands in particular, has been deeply studied since the last century, the same does not hold true for coastal marine areas. Given the importance of coastal areas for seabirds worldwide and, at the same time, the high vulnerability of both, looking into the role of seabirds in influencing the ecosystem functioning in coastal areas is needed nowadays. Here,…
66 In vitro comparison of six raw materials on gastric ecosystem activity and acidity
2021
International audience; The great biochemical variability of the raw materials used in horse feeds can induce changes in gastric fermentation, and therefore affect gastric health through the resulting acidity of the bacterial end products. This in vitro trial compared the effect of 6 raw materials (BA: barley; WB: wheat bran; OA: oats; SM: sunflower meal; SB: sugar beet pulp; AL: alfalfa – Table 1) commonly used in horse feeds on gastric bacterial fermentation and buffering capacity. In 3 horses fed a mixture of the 6 raw materials 3h before sampling, gastric chyme was collected via a nasogastric tube and mixed. Bottles containing 1mL of the mixed gastric chymes, 50mL dilution medium and 1.…
Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus)
2015
Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most hostparasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in populationpairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide…
Agroecosystems shape population genetic structure of the greenhouse whitefly in Northern and Southern Europe
2014
International audience; Background: To predict further invasions of pests it is important to understand what factors contribute to the genetic structure of their populations. Cosmopolitan pest species are ideal for studying how different agroecosystems affect population genetic structure within a species at different climatic extremes. We undertook the first population genetic study of the greenhouse whitefly (Trialeurodes vaporariorum), a cosmopolitan invasive herbivore, and examined the genetic structure of this species in Northern and Southern Europe. In Finland, cold temperatures limit whiteflies to greenhouses and prevent them from overwintering in nature, and in Greece, milder tempera…
Hybridization between mouse lemurs in an ecological transition zone in southern Madagascar
2009
Hybrid zones in ecotones can be useful model systems for the study of evolutionary processes that shape the distribution and discreteness of species. Such studies could be important for an improved understanding of the complex biogeography of Madagascar, which is renowned for its outstanding degree of small-scale endemism. Certain forest remnants in central Madagascar indicate that transitional corridors across the island could have connected microendemics in different forest types in the past. Evolutionary processes in such corridors are difficult to study because most of these corridors have disappeared due to deforestation in central Madagascar. We studied a hybrid zone in one of the few…