Interactive effects of hydrology and fire drive differential biogeochemical legacies in subtropical wetlands

Fire is an important component of many ecosystems, as it impacts biodiversity, biogeochemical cycles, and primary production. In wetlands, fire interacts with hydrologic regimes and other ecosystem characteristics to determine soil carbon (C) gains or losses and rates of nutrient cycling. However, how legacies of fire interact with wetland hydroperiod to affect soil chemistry is uncertain. We used the Florida Everglades as a model landscape to study how fire regimes, hydroperiod, and soil types collectively contribute to long-term C, nitrogen (N), and phosphorus (P) concentrations and stoichiometric mass ratios (C:N, C:P, N:P) in both short- and long-hydroperiod subtropical wetlands that consist of marl and peat soils, respectively. We used fire records from 1948 to 2018 and hydroperiod from 1991 to 2003, and analyzed these data together with soil chemistry data collected during two extensive field surveys (n = 539) across different ecosystem and soil types throughout Everglades National Park. We also analyzed macrophyte and periphyton P concentrations (n = 150) collected from 2003 to 2016 in fire-impacted wetland sites. Hydroperiod was the main driver of soil C concentration in both marl and peat soils, but fire played a substantial role in nutrient cycling. Particularly in marl soils, soil P concentrations were affected by the absence of fire. In the first decade post-fire, we observed an amplification of P cycling with decreased soil C:P ratios by 95% and N:P ratios by 45%. After more than a decade post-fire, soil P became increasingly depleted (41% lower). Macrophyte P tissue concentration was 50% higher only in the first year post-fire, whereas periphyton P did not change. By recycling nutrients and through removal of litter accumulation, which forms a physical obstacle to photosynthesis, fire likely helps maintain high levels of macrophyte aboveground live biomass as well. Given its substantial effect on nutrient cycling, we advocate for fire management that uses fire return intervals that minimize depletion of soil nutrients and promote positive feedbacks to productivity in wetland ecosystems. In addition, coordinated management of fire return intervals and wetland hydroperiod can be used to set priorities for wetland soil nutrient concentrations and ratios

Measured and Modeled C Flows after Land Use Change to Perennial Bioenergy Crops

In the first part of this Thesis the general concepts and state of art of the research subjects are introduced, then focusing on the impact of the land use change to perennial bioenergy crops on agricultural systems’ carbon stocks. Then, the specific objectives of the research that has been carried out are stated. In the second part, the detailed methods and results of the four experiments performed are described one by one. All four papers constitute original research. The first and second papers originate from direct field measurements investigating the carbon flows subsequent to the establishment of perennial grasses for bioenergy on, respectively, a fertile agricultural land and a marginal land resembling, since it had been cultivated with poplar for the previous thirty years, the conditions of a biomass supply district. The third and fourth papers originate from model simulations investigating the potential of perennial biomass crops to produce energy and second-generation biofuels at the regional scale and their impact on soil carbon stocks and, more generally, on greenhouse gases emissions. Finally, by converging the findings of all the four experiments, general conclusions are drawn, also underlying future perspectives, current gaps and further research needed in order to fill these gaps

Four‐year measurement of net ecosystem gas exchange of switchgrass in a Mediterranean climate after long‐term arable land use

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Valutazione multicriteriale della suscettività a interventi di rinaturalizzazione dei rimboschimenti di pino nero e dei soprassuoli di cerro in Toscana

La rinaturalizzazione è uno degli orientamenti colturali di riferimento della gestione sostenibile di formazioni forestali semplificate nella composizione e nella struttura. La pianificazione degli interventi su area vasta può essere utilmente supportata da informazioni georeferenziate sulle condizioni di suscettività alla rinaturalizzazione dei complessi boscati. Nel presente lavoro si applica un approccio multicriteriale alla mappatura della suscettività a interventi di rinaturalizzazione dei rimboschimenti di pino nero (Pinus nigra Arn.) e soprassuoli di cerro (Quercus cerris L.) presenti in Toscana. La valutazione è basata su un approccio fuzzy, mediante costruzione di funzioni di appartenenza in grado di esprimere il variare delle condizioni di suscettività in rapporto ai seguenti fattori mappati su base raster: i) efficienza ecobiologica del popolamento forestale, stimata mediante un indice guidato da dati telerilevati, e utilizzata per definire il grado di opportunità colturale dell’intervento; ii) fattori di contesto (grado di adiacenza del soprassuolo con altre tipologie forestali e diversità fisionomica della copertura forestale a scala locale) intesi come fattori in grado di rafforzare (o depotenziare) l’opportunità colturale dell’intervento; iii) accessibilità e dimensione del soprassuolo, condizionanti la fattibilità operativa dell’intervento. I valori fuzzy dei singoli fattori sono combinati mediante una funzione moltiplicativa in un indice sintetico di suscettività, per individuare a scala vasta ambiti territoriali a cui accordare priorità di intervento. Su scala comprensoriale o aziendale, la disponibilità di indicatori più puntuali può permettere di collegare in maniera coerente gli indirizzi della pianificazione di area vasta alla concreta programmazione degli interventi

Synergic use of satellite and ground based remote sensing methods for monitoring the San Leo rock cliff (Northern Italy)

AbstractThe historic town of San Leo (Emilia Romagna Region, northern Italy) is located on top of an isolated rock massif above the Marecchia River valley hillside. On February 27th 2014, a northeastern sector of the massif collapsed; minor structural damages were reported in the town and a few buildings were evacuated as a precautionary measure. Although no fatalities occurred and the San Leo cultural heritage suffered no damage, minor rock fall events kept taking place on the newly formed rock wall, worsening this hazardous situation. In this framework, a monitoring system based on remote sensing techniques, such as radar interferometry (both spaceborne and ground-based) and terrestrial laser scanning, was planned in order to monitor the ground deformation of the investigated area and to evaluate the residual risk. In this paper the main outlines of a 1-year monitoring activity are described, including a pre-event analysis of possible landslide precursors and a post-event analysis of the displacements of both the collapse-affected rock wall sector and the rock fall deposits

Calixarenes Incorporating Sulfonamide Moieties: Versatile Ligands for Carbonic Anhydrases Inhibition

Carbonic anhydrases (CAs) continue to represent a relevant pharmaceutical target. The need of selective inhibitors and the involvement of these metalloenzymes in many multifaceted diseases boost the search for new ligands able to distinguish among the different CA isoforms, and for multifunctional systems simultaneously able to inhibit CAs and to interfere with other pathological events by interacting with additional targets. In this work, we successfully explored the possibility of preparing new CAs ligands by combining calixarenes with benzensulfonamide units. Inhibition tests towards three human CA isoforms evidenced, for some of the ligands, Ki values in the nanomolar range and promising selectivity. X-ray and molecular modeling studies provided information on the mode of binding of these calixarene derivatives. Thanks to the encouraging results and the structural features typical of the calixarene scaffold, it is then possible to plan for the future the design of multifunctional inhibitors for this class of widely spread enzymes