Assessment of soil erosion in karst regions of Havana,Cuba     

J.M. Febles‐Gonzlez  M.B. Vega‐Carreo  A. Toln‐Becerra  X. Lastra‐Bravo 《Land Degradation \u0026amp; Development》2012,23(5):465-474

Only recently have erosion models begun to be used in research work in Cuba, specifically the USLE and the thematic cartography of factors in a GIS framework without using a specific model. It therefore becomes necessary to include simulation models for karst regions that make possible an integral assessment of the specific types of soil erosion in those environments and take into consideration the effects of climate change in soil management systems. Morphometric analysis of karst doline absorption forms in regions of La Habana Province in 1986, 1997, and 2009 allowed the characterisation and application of the Morgan Morgan Finney (MMF) conceptual empirical erosion model in the Country for the first time. The results showed previously unreported losses of 12·3–13·7 t of soil ha ⁻¹ y⁻¹, which surpasses the permissible erosion threshold. Furthermore, it clearly shows the unsustainable trend of Red Ferralitic and Ferrasol Rhodic (World Reference Base) soils use. The model applied considered the effects of extreme rainfall events associated with climate change in recent years. The results found have led to strategies for coping with future climate change in each scenario and have made it possible to evaluate the consequences. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Utilization of Marine Waste to Obtain β-Chitin Nanofibers and Films from Giant Humboldt Squid Dosidicus gigas     

Gustavo Cabrera-Barjas  Cristian Gonzlez  Aleksandra Nesic  Kelly P. Marrugo  Oscar Gmez  Cdric Delattre  Oscar Valdes  Heng Yin  Gaston Bravo  Juan Cea 《Marine drugs》2021,19(4)

β-chitin was isolated from marine waste, giant Humboldt squid Dosidicus gigas, and further converted to nanofibers by use of a collider machine under acidic conditions (pH 3). The FTIR, TGA, and NMR analysis confirmed the efficient extraction of β-chitin. The SEM, TEM, and XRD characterization results verified that β-chitin crystalline structure were maintained after mechanical treatment. The mean particle size of β-chitin nanofibers was in the range between 10 and 15 nm, according to the TEM analysis. In addition, the β-chitin nanofibers were converted into films by the simple solvent-casting and drying process at 60 °C. The obtained films had high lightness, which was evidenced by the CIELAB color test. Moreover, the films showed the medium swelling degree (250–290%) in aqueous solutions of different pH and good mechanical resistance in the range between 4 and 17 MPa, depending on film thickness. The results obtained in this work show that marine waste can be efficiently converted to biomaterial by use of mild extractive conditions and simple mechanical treatment, offering great potential for the future development of sustainable multifunctional materials for various industrial applications such as food packaging, agriculture, and/or wound dressing.  相似文献   

Historical soil amendment with charcoal increases sequestration of non‐charcoal carbon: a comparison among methods of black carbon quantification          下载免费PDF全文

B. Kerré  C. T. Bravo  J. Leifeld  G. Cornelissen  E. Smolders 《European Journal of Soil Science》2016,67(3):324-331

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Carbon sequestration in Spanish Mediterranean forests under two management alternatives: a modeling approach   总被引：2，自引：0，他引：2  

F. Bravo  A. Bravo-Oviedo  L. Diaz-Balteiro 《European Journal of Forest Research》2008,127(3):225-234

Management implications associated with two different silvicultural strategies in two Spanish pine forests (Scots pine stands in northern Spain and Mediterranean Maritime pine stands in Central Spain) were explored. Whole-stand yield, growth models and individual tree equations were used to estimate carbon stock in forests under different silvicultural alternatives and site indexes. Each alternative was evaluated on the basis of the land expectation value (LEV). Results reveal the appropriateness of implementing carbon payments, because it can clearly complement traditional management objectives in economic terms. Longer rotations on the poorest sites result in a positive economic return by introducing carbon output. The proportion of carbon stock in the final harvest relative to total fixed carbon is always higher in long rotation scenarios. However, short rotation systems produce the highest values of carbon MAI regardless of site index. The impact of carbon price is higher on the Maritime pine stands than on Scots pine stands. For both the species, changes in the discount rate have a minor impact on Carbon LEV. Notwithstanding, the proportion of total LEV due to carbon is greater when the discount rate increases.  相似文献   

Developing a prescription for brush control in the Chaco region,effects of combined treatments on the canopy of three native shrub species     

R. Ledesma  C. Kunst  S. Bravo  M. Leiva  L. Lorea  J. Godoy 《Arid Land Research and Management》2018,32(3):351-366

Shrub encroachment is frequent in grazing lands in the Chaco region, Argentina. Fire is used by cattlemen to reduce the dominance of the shrub stands, improve forage standing biomass and quality, and enhance grazing accessibility. In this research, we assessed the combined effect of roller chopping?+?fire on the plant canopy of three native shrub species, Acacia gilliessi, Celtis ehrenbergiana, and Schinus bumelioides. We used a randomized design, with three factors, year, burn dates, and fine fuel load. Before the burn, the area received a roller-chopping treatment. Canopy volume reduction was assessed using, DifV?=??1*(V_i???V_a) and DifS?=??1*(S_i???S_a), respectively, where V?=?plant volume and S?=?sprout number. Suffixes i and a represent measurements taken before the roller-chopping treatment and one growth season after the fire, respectively. Fire intensity, headfire residence time, woody residues, and initial plant volume were evaluated as covariates. Results indicate a negative fire effect on canopy volume and sprouting. A. gilliesi was more susceptible to fire than the other two species. High fine fuel load and high fire intensity generated a severe effect on sprout number. The same trend was observed for coarse fuels. The canopy volume reduction was greater in A. gilliesi than the other species, reaffirming its high susceptibility to fire. Head fires were faster in 2009 than in 2008 and in the late than in the early burn dates. These results suggest that mechanical?+?fire treatments can be useful management tools for controlling shrub encroachment in the western Chaco.  相似文献   

Fishway with two entrance branches: Understanding its performance for potamodromous Mediterranean barbels          下载免费PDF全文

F. J. Bravo‐Córdoba  F. J. Sanz‐Ronda  J. Ruiz‐Legazpi  L. Fernandes Celestino  S. Makrakis 《Fisheries Management and Ecology》2018,25(1):12-21

Many fish passes have been built across the world in recent years. This study analyses the performance of a modified type of pool and weir fishway with two access branches, using passive integrated transponder telemetry. A circum‐Mediterranean barbel, Luciobarbus bocagei (Steindachner, 1864), was chosen as the target species. Both hydraulic values (flow and volumetric energy dissipation) and biological parameters (attraction, entrance and passage success) were measured in the fishway, these being related to the environmental variables affecting upstream fish movement. Flow discharge, water temperature and atmospheric pressure were important for fish entering the fishway. There was no preference between path routes, even though the main discharge was concentrated in the turbine channel. This type of fishway design could be an alternative for the conservation of fish populations where multiple fish approach options are possible.  相似文献   

Limited performance of MALDI‐TOF for identification of fish Aeromonas isolates at species level          下载免费PDF全文

M Pérez‐Sancho  I Cerdá  A Fernández‐Bravo  L Domínguez  M J Figueras  J F Fernández‐Garayzábal  A I Vela 《Journal of fish diseases》2018,41(10):1485-1493

The aim of this study was to evaluate the usefulness of the MALDI‐TOF MS to identify 151 isolates of Aeromonas obtained mostly from diseased fish. MALDI‐TOF MS correctly identified all isolates to the genus level but important differences in the percentage of isolates correctly identified depending on the species were observed. Considering exclusively the first identification option, Aeromonas bestiarum, Aeromonas hydrophila, Aeromonas salmonicida, Aeromonas veronii and Aeromonas sobria were the best identified with results >95%. However, considering the first and second identification options, the only species that showed values >90% was A. hydrophila. Overall, when the database was supplemented with 14 new spectra, the number of accurate identifications increased (41% vs. 55%) and the number of inconclusive identifications decreased (45% vs. 29%), but great differences in the success of species‐level identifications were found. Species‐distinctive mass peaks were identified only for A. hydrophila and A. bestiarum (5003 and 7360 m/z in 95.5% and 94.1% of their isolates, respectively). This work demonstrates the utility of MALDI‐TOF MS for Aeromonas identification to the genus level, but there is no consistency for the accurate identification of some of the most prevalent species implicated in fish disease.  相似文献   

Factors determining enzyme activities in soils under <Emphasis Type="Italic">Pinus halepensis</Emphasis> and <Emphasis Type="Italic">Pinus sylvestris</Emphasis> plantations in Spain: a basis for establishing sustainable forest management strategies     

Teresa Bueis  María Belén Turrión  Felipe Bravo  Valentín Pando  Adele Muscolo 《Annals of Forest Science》2018,75(1):34

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Site factors as predictors for <Emphasis Type="Italic">Pinus halepensis</Emphasis> Mill. productivity in Spanish plantations     

Teresa Bueis  Felipe Bravo  Valentín Pando  María-Belén Turrión 《Annals of Forest Science》2017,74(1):6

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Dynamics of ecosystem services in <Emphasis Type="Italic">Pinus sylvestris</Emphasis> stands under different managements and site quality classes     

Rafael Alonso Ponce  Sonia Roig  Alfredo Bravo  Miren del Río  Gregorio Montero  Marta Pardos 《European Journal of Forest Research》2017,136(5-6):983-996

Timber and biodiversity are considered two antagonistic ecosystem services (ES), largely influenced by silviculture and site ecological conditions. In order to address the trade-offs between these two ES over time, we performed a retrospective study at compartment level in the Pinus sylvestris forests of the Spanish Central Mountain System. Archival data from Management Plans for eight forests with contrasting silvicultural systems (uniform shelterwood system, group shelterwood system, irregular shelterwood system,) and three different site quality classes were analysed. Timber production was assessed through stand volume, harvested timber volume and a stand volume index. Biodiversity was examined through structural diversity (Gini index, Shannon tree size diversity index, Simpson’s reciprocal index and evenness index, all applied to diameter classes) and the abundance of large living trees. For all silvicultural systems investigated, stand volume and harvested timber volume have grown since the beginning of the management plans (beginning of the twentieth century in some forests). The largest yields of timber corresponded to the best quality sites with more intensive silvicultural treatments (uniform and group shelterwood systems). The uniform shelterwood system showed lower figures for structural diversity, though not always significant. The best site qualities maintained notable structural diversity values, even under the most intensive management system. The application of the different management systems over decades has revealed a synergy between timber production and structural diversity, particularly in those systems maintaining more than one age class, although results are conditioned by forest harvesting history. The interaction between historical silvicultural treatment and site quality has been identified as an important source of information to understand forest dynamics and functioning of ES provision.  相似文献