Implications of climate change on the distribution and conservation of Cabo Verde endemic trees

Climate change is one of the most significant challenges to biodiversity conservation, particularly in dry tropical islands, such as the Cabo Verde archipelago where only three endemic tree taxa occur – Dracaena draco subsp. caboverdeana, Phoenix atlantica and Sideroxylon marginatum – all classified as threatened. The main goal of this study was to predict the possible shifts in the climatically suitable habitat ranges for Cabo Verdean endemic tree species under different climate change scenarios. We applied species distribution models (SDMs) to the available occurrence data, and projected the distribution of the three taxa for 2050 and 2080, according to the expected climate change scenarios. The best models were obtained using the Random Forest algorithm; they showed that, by 2080, the suitable habitat for Dracaena draco subsp. caboverdeana and Sideroxylon marginatum will have decreased by 28% and 34%, respectively; conversely, the suitable habitat will have increased by 59% for Phoenix atlantica, the taxon best adapted to arid conditions. Additionally, Santo Antão is the island where endangered trees are more encompassed by protected areas. Overall, this study contributed with new integrated data to support the design and implementation of a strategic plan to promote the conservation and ecological value of Cabo Verde endemic trees in this climatically vulnerable country.info:eu-repo/semantics/publishedVersio

Implications of climate change on the distribution and conservation of Cabo Verde endemic trees

Climate change is one of the most significant challenges to biodiversity conservation, particularly in dry tropical islands, such as the Cabo Verde archipelago where only three endemic tree taxa occur – Dracaena draco subsp. caboverdeana, Phoenix atlantica and Sideroxylon marginatum – all classified as threatened. The main goal of this study was to predict the possible shifts in the climatically suitable habitat ranges for Cabo Verdean endemic tree species under different climate change scenarios. We applied species distribution models (SDMs) to the available occurrence data, and projected the distribution of the three taxa for 2050 and 2080, according to the expected climate change scenarios. The best models were obtained using the Random Forest algorithm; they showed that, by 2080, the suitable habitat for Dracaena draco subsp. caboverdeana and Sideroxylon marginatum will have decreased by 28% and 34%, respectively; conversely, the suitable habitat will have increased by 59% for Phoenix atlantica, the taxon best adapted to arid conditions. Additionally, Santo Ant˜ao is the island where endangered trees are more encompassed by protected areas. Overall, this study contributed with new integrated data to support the design and implementation of a strategic plan to promote the conservation and ecological value of Cabo Verde endemic trees in this climatically vulnerable countryinfo:eu-repo/semantics/publishedVersio

Present and future distribution of Faidherbia albida in Cabo Verde as revealed by climatic modelling and LULC analysis

Climate change poses one of the most significant challenges to conserve biodiversity, especially in tropical dry islands, as is the case of Cabo Verde (northeast Atlantic Ocean). This archipelago has a low percentage of forest cover and hosts only seven native tree species, among them, Faidherbia albida (Delile) A.Chev. (Fabaceae). Therefore, protective afforestation is extremely important in Cabo Verde, one of the most vulnerable West African countries to climate change. With this work, we aimed to estimate the current distribution and potential shifts in suitable areas for F. albida under climate change, using species distribution models (i.e., random forest, generalized linear and additive models), covering its distribution range in Cabo Verde and mainland Africa. The best model was then projected for the studied area, at two different slice times, using Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Based on current bioclimatic variables, we estimated that almost two thirds of Cabo Verde’s territory is highly suitable for F. albida, which contrasts with its current occurrence. By overlaying the present habitat suitability with land use and land cover data, we concluded that habitat availability and suitability could be constrained by that factor. On average, the predicted suitable habitat for future distributions gradually decreases by 2080 under both scenarios compared with the current, with a smaller effect of RCP4.5 than of RCP8.5. Local authorities can benefit from this research and develop actions to promote sustainable reforestation in Cabo Verde, which should include native tree species that are best adapted to the local climate and could thus contribute to mitigate the effects of climate change.info:eu-repo/semantics/publishedVersio

Mechanisms implemented for the sustainable development of agriculture: an overview of Cabo Verde performance

In 2005, the Economic Community ofWest African States (ECOWAS) adopted the Common Agricultural Policy of ECOWAS (ECOWAP), as an instrument for implementing the Comprehensive Africa Agriculture Development Program (CAADP). The main goals of ECOWAP/CAADP were set to promote agriculture development and end hunger by 2025. In this study we focused on the Cabo Verde archipelago as one of the best performing countries within ECOWAS in terms of overall sustainable development. In this paper, the evolution of the ECOWAP implementation and of the Sustainable Development Goals (SDGs) associated with agriculture in Cabo Verde, were assessed by semi-quantitative (e.g., agricultural policies, agrarian periodical literature) and quantitative (modeling regression of ECOWAP implementation and Sustainable Development Goals—SDGs—performance) analyses. Our integrated results suggest that the agriculture development strategies, the signature of ECOWAP/CAADP by the national government, and political stability might explain the progress made towards poverty reduction and the improvement of food security. The results also show that agriculture-related SDGs in Cabo Verde are higher than the mean values obtained from the remaining West African countries, well above the top 25% WA countries. Nevertheless, Cabo Verde public expenditure into agriculture under the ECOWAP was generally below the targeted 10% of the national budget, with food import required to meet internal food demandsinfo:eu-repo/semantics/publishedVersio

Growth and Characterization of Cu2Zn1-xFexSnS4 Thin Films for Photovoltaic Applications.

Photovoltaics is a promising technology to produce sustainable energy, thanks to the high amount of energy emitted by the sun. One way of having solar cells with low production costs is to apply thin-film technology and with earth-abundant raw materials. A keen interest is arising in kesterite compounds, which are chalcogenides composed of abundant and non-toxic elements. They have already achieved excellent performance at the laboratory level. Here, we report the synthesis and characterization of mixed chalcogenides based on copper, zinc, iron, and tin. Solutions have been studied with different zinc and iron ratios. The distortion of the elementary cell of kesterite increases with the addition of iron until a phase transition to stannite occurs. The process of synthesis and deposition proposed herein is cheap and straightforward, based on the sol-gel technique. These thin films are particularly attractive for use in cheap and easily processable solar cells. The synthesized layers have been characterized by X-ray diffraction, UV-Vis absorption, and Raman, X-ray photoelectron, and energy-dispersive X-ray spectroscopy measurements

Investigadores da UAc e do ISA publicam dois artigos sobre as implicações das alterações climáticas na distribuição e conservação das árvores endémicas e nativas de Cabo Verde

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.Os investigadores Danilson Varela (Nova Business Shool, CIBIO), Maria Romeiras (ISA, LEAF) e Luís Silva (UAc, CIBIO) publicaram dois estudos técnico-científicos nas revistas internacionais “Frontiers in Ecology and Evolution” e “Global Ecology and Conservation”, acerca dos fatores climáticos que afetam a distribuição das árvores endémicas e nativas de Cabo Verde. […].info:eu-repo/semantics/publishedVersio

Photoluminescence properties of polycrystalline AgGaTe 2

Abstract Due to its high absorption coefficient and close to optimal bandgap energy, AgGaTe 2 is a promising material for solar energy conversion. In order to avoid recombination losses, the study of the defect structure of solar cell materials is very important. This paper reports the results of photoluminescence experiments on polycrystalline AgGaTe 2 . Two emission regions centred at 1.32 and 0.8 eV were found. The first region appears near the bandgap energy and comprises three bands that are identified by the theory of heavily doped semiconductors as the band-to-band (1.337 eV), the band-to-tail (1.317 eV) and the band-to-impurity (1.287 eV) recombination. The second deep PL region consists of two bands with the peak energies of 0.835 and 0.75 eV. Both these deep bands have rather low thermal activation energy; 18.5 and 20.8 meV, respectively. The possible origins of these bands are discussed.

Isothermal and Two-Temperature Zone Selenization of Mo Layers

Glass/Mo, Mo foil, glass/Mo/In, and glass/Mo/Cu stacked layers were selenized in closed vacuum tubes by isothermal and/or two-temperature zone annealing in Se vapors. The selenization process was studied dependent on Se vapor pressure, temperature and time. Samples were selenized from 375 to 580°C for 30 and 60 minutes. The applied Se pressure was varied between 130 and 4.4⋅103 Pa. The increase of MoSe2 film thickness was found to depend on the origin of Mo. MoSe2 thickness dL on Mo-foil was much higher than on sputtered Mo layers, and it depended linearly on time and as a power function dL~PSe1/2 on Se vapor pressure. The residual oxygen content in the formed MoSe2 layers was much lower in the two-zone selenization process. If Mo was covered with Cu or In before selenization, these were found to diffuse into formed MoSe2 layer. All the MoSe2 layers showed p-type conductivity

Anion Effect of Zinc Source on Chemically Deposited ZnS(O,OH) Films

The study on the anion effect of different Zn sources—Zn(CH3COO)2, ZnCl2, ZnI2, Zn(NO3)2 and ZnSO4—on the chemical deposition of ZnS(O,OH) films revealed that the growth rate and composition of the ZnS(O,OH) layer depend on the instability constant (pK) value of the corresponding Zn-complex Zn(L)n in the chemical bath solution. In the region of pKZn(NH3)2+>pKZn(L)n the ZnS(O,OH) film's growth rate and ZnS concentration in films increased with the increasing pK value of the used Zn salt complex up to the pK value of the Zn[NH3]2+ complex and decreased in the region where pKZn(NH3)2+<pKZn(L)n. The band gap values (around 3.6 eV in most cases) of deposited ZnS(O,OH) films did not depend on the Zn precursor's instability constant, the ZnS(O,OH) film from zinc nitrate containing bath has higher band gap energy (Eg = 3.8 eV). The maximum efficiency of CISSe and CZTSSe monograin layer solar cells was gained with ZnS(O,OH) buffer layer deposited from CBD solution containing Zn(CH3COO)2 as Zn source, which provided the highest growth rate and ZnS concentration in the ZnS(O,OH) film on glass substrates

Excitonic emission in heavily Ga-doped zinc oxide films grown on GaN

n/aFunding Agencies|Angpanneforeningens Forskningsstiftelse [16-541]; VRSwedish Research Council [2018-04962, 2016-05362]; Swedish Research Council (VR) Marie Sklodowska Curie International Career Grant [2015-0067900GREEN 2D FOX]; AForsk [14-517]; European Regional Development Fund Project TK141 "Advanced materials and high-technology devices for energy recuperation systems"</p