Water use partitioning of native and non‐native tree species in riparian ecosystems under contrasting climatic conditions

1. One of the suggested mechanisms behind the success of non- native plants in recipient ecosystems is competition avoidance with natives by means of differ-ent resource-use strategies, such as deeper water uptake under dry conditions.2. We aimed at evaluating water source partitioning between native and non- native tree species coexisting in central Spain floodplains; determining the dependency on drought stress of such water sources use; and assessing if the reliance on deeper water sources relates with physiological and growth performance.3. We assessed water uptake depth, leaf functional traits related to physiological performance and growth of native (Populus alba) and non- native trees (Ailanthus altissima, Robinia pseudoacacia) coexisting in riparian forests under different drought conditions (drier, intermediate and wetter). We analysed δ2H and δ18O isotopes in xylem water and in soil water from top, mid and deep soil depths and determined the contribution of each water source to overall plant xylem water. Leaf traits re-lated with resource use and secondary growth were assessed for each species.4. We found stronger differences between sites than between species, with all species taking more deep water in the driest site (~45% of the xylem water) than in the wettest (~15%). However, under drier conditions, species differences were significant for top-soil water use, with R. pseudocacia withdrawing more super-ficial water (~22%) than A. altissima (~8%). These results indicate stronger water partitioning under drier conditions. Non- native species showed a physiological strategy characterized by greater leaf N, water content, and enriched δ13C and δ15N values independently of the deep-water uptake. However, a positive rela-tionship between deep soil water use and such strategy was found for P. alba .5. We highlight that those native and non- native species differences were more evident regarding physiological performance at leaf level than for deep-water uptake or growth. Furthermore, our results suggest that differences in water sources used by coexisting species may increase under drier conditions.info:eu-repo/semantics/publishedVersio

Discriminação do perfil aromático de cafés e misturas industriais de acordo com o valor cromático

Different polymeric phases have been used in order to perform roasted coffee aroma analysis although not in a systematic way. Variations in the type of SPME polymer and sample composition make experimental results interpretation difficult and may hinder coffee blend differentiation. In the present work, static headspace solid phase microextraction using carboxen/polydimethylsiloxane polymeric fibre (HS-SPME(CAR/PDMS)) followed by gas chromatography-mass spectrometry (GC-MS), revealed the best analytical performance to characterize the aroma profile of coffees and industrial blends with different chromaticvalues (64.9, 70.6, 75.3, 86.1 and 89.6). The most relevant classes of aroma compounds founded were pyrroles, ketones, pyrazines, furans, phenolics, pyridines, alcohols and acids, independent of the degree of roasting. By combining the analytical methodology with principal component analysis (HS-SPME (CAR/PDMS)/GC-MS/PCA), important aroma compounds such as 2-furancarboxaldehyde, 2-furanmethanol and acetic acid, allows to discriminate the different degrees of roasting, from light (chromatic value 89.6) to dark(chromatic value 64.9) roast. The proposed analytical approach may help to build aroma profile databases to allow a better evaluation of coffee blend quality, and in controlling the industrial roasting processes.Diferentes fases poliméricas têm sido utilizadas, a fim de realizar-se a análise do aroma do café torrado, embora isso não tenha sido feito de forma sistemática. Variações no tipo de polímero de SPME, bem como na composição da amostra tornam a interpretação dos resultados experimentais difícil o que pode inclusive interferir em tentativas de diferenciação de diferentes misturas de café. No presente trabalho, a microextração de fase sólida para análise estática de “espaço-de-cabeça”, utilizando o polímero carboxen/polidimetilsiloxano (HS-SPME (CAR/PDMS)), associada a cromatografia gasosa acoplada a espectrometria de massa (GC-MS), revelou o melhor desempenho analítico na caracterização do perfil aromático de cafés e misturas industriais, com diferentes valores cromáticos (64,9, 70,6, 75,3, 86,1 e 89,6). As classes de compostos aromáticos mais importantes identificadas nos cafés foram: pirróis, cetonas, pirazinas, furanos, fenóis, piridinas, álcoois e ácidos, independentemente do grau de torra. Aocombinar a metodologia analítica com a análise de componentes principais (HS-SPME (CAR/PDMS)/GC-MS/PCA), verificou-se que os compostos aromáticos furancarboxaldeído, 2-furanmethanol e ácido acético permitem discriminar os diferentes graus de torrefação. A abordagem proposta neste estudo pode ajudar a construir bases de dados de perfis aromáticos de uma maneira mais robusta,permitindo uma melhor avaliação da qualidade de misturas de café e melhor controle do processo industrial de torração

Acorn isotopic composition: A new promising tool for authenticity maps of Montado’s high-value food products

It is often overlooked that even food production is linked to the ecology of plants and animals. Living organisms respond to environmental short-and long-term variability: acknowledging this may help in the ultimate goal of valorizing a territory/product. We investigated acorns of the two main Quercus species of the Portuguese Montado, a main feed of the renown black Iberian pig. We tested their responses to an aridity gradient by morphological parameters and isotopic signature. Q. rotundifolia and Q. suber acorns did not differ morphologically, even if a higher variability in all parameters was observed in acorns of Q. suber. According to the site-specific Aridity Index, correlations are indicative to higher weight and length only in Q. suber acorns from more arid sites. As for isotopic composition, there were no differences in nitrogen or carbon (δ15N and δ13C) between the two species. However, combining the samples and testing for association with the Aridity Index, we found that more arid sites lead to a 15N enrichment. This result, combined with the positive correlation between AI and acorns length, support the use of acorns as a tool, their isoscapes of nitrogen being a stepping stone for the provenance of the black Iberian pig.info:eu-repo/semantics/publishedVersio

Sustainable Urban Agriculture using Compost and an Open-pollinated Maize Variety

Global urbanization leads to the loss of periurban farming land and increases dependency on distant agriculture systems. This provokes greenhouse gas emissions associated with transportation and storage while disconnecting nutrient cycles, as urban organic waste is not recycled into the agricultural system. Urban food production based on composted local biomass could reduce these problems, but currently used hybrid crops rely strongly on inorganic fertilizers. On the contrary, open-pollinated varieties were bred for productivity under organic fertilization, such as compost. Hypothesising that open-pollinated varieties retain high nutritional value under low nutrient conditions, a commercial hybrid and a local open-pollinated variety of maize were cultivated in non-fertilized soil and under two compost applications: Municipal compost as high nutrient input or locally produced green waste compost and municipal compost mix, as medium nutrient input. Unfertilized plots exhibited low grain production (1.9 t/ha), but yields under green waste compost/municipal compost (6.1 t/ha) and municipal compost (7.8 t/ha) treatments were comparable to observations from maize under inorganic fertilization. Contrary to the commercial variety, the open-pollinated variety exhibited higher grain micronutrient concentrations, e.g. 220% higher zinc concentrations and lower accumulation of heavy metals, e.g. 74% lower nickel concentrations. This variety-related effect was found in all treatments and was independent of soil micronutrient concentrations. In conclusion, both compost mixes were effective in increasing grain yield in both maize varieties. However, the open-pollinated variety produced grain with higher nutritional values in soil and all treatments, indicating it is potentially better suited for compost-based sustainable urban agriculture

Partitioning carbon fluxes in a Mediterranean oak forest to disentangle changes in ecosystem sink strenght during drought

Net carbon flux partitioning was used to disentangle abiotic and biotic drivers of all important component fluxes influencing the overall sink strength of a Mediterranean ecosystem during a rapid spring to summer transition. Between May and June 2006 we analyzed how seasonal drought affected ecosystem assimilation and respiration fluxes in an evergreen oak woodland and attributed variations in the component fluxes (trees, understory, soil microorganisms and roots) to observations at the ecosystem scale. We observed a two thirds decrease in both ecosystem carbon assimilation and respiration (Reco) within only 15 days time. The impact of decreasing Reco on the ecosystem carbon balance was smaller than the impact of decreasing primary productivity. Flux partitioning of GPP and Reco into their component fluxes from trees, understory, soil microorganisms and roots showed that declining ecosystem sink strength was due to a large drought and temperatureinduced decrease in understory carbon uptake (from 56% to 21%). Hence, the shallow-rooted annuals mainly composing the understory have a surprisingly large impact on the source/ sink behavior of this open evergreen oak woodland during spring to summer transition and the timing of the onset of drought might have a large effect on the annual carbon budget. In response to seasonal drought Reco was increasingly dominated by respiration of heterotrophic soil microorganisms, while the root flux was found to be of minor importance. Soil respiration flux decreased with drought but its contribution to total daily CO2-exchange increased by 11.5%. This partitioning approach disentangled changes in respiratory and photosynthetic ecosystem fluxes that were not apparent from the eddy-covariance or the soil respiration data alone. By the novel combination of understory vs. overstory carbon flux partitioning with soil respiration data fromtrenched and control plots, we gained a detailed understanding of factors controlling net carbon exchange of Mediterranean ecosystem

From a Lose–Lose to a Win–Win Situation: User-Friendly Biomass Models for Acacia longifolia to Aid Research, Management and Valorisation

Woody invasive species pose a big threat to ecosystems worldwide. Among them, Acacia longifolia is especially aggressive, fundamentally changing ecosystem structure through massive biomass input. This biomass is rarely harvested for usage; thus, these plants constitute a nuisance for stakeholders who invest time and money for control without monetary return. Simultaneously, there is an increased effort to valorise its biomass, e.g., for compost, growth substrate or as biofuel. However, to incentivise A. longifolia harvest and usage, stakeholders need to be able to estimate what can be obtained from management actions. Thus, the total biomass and its quality (C/N ratio) need to be predicted to perform cost–benefit analyses for usage and determine the level of invasion that has already occurred. Here, we report allometric biomass models for major biomass pools, as well as give an overview of biomass quality. Subsequently, we derive a simplified volume-based model (BM ~ 6.297 + 0.982 × Vol; BM = total dry biomass and Vol = plant volume), which can be applied to remote sensing data or with in situ manual measurements. This toolkit will help local stakeholders, forest managers or municipalities to predict the impact and valorisation potential of this invasive species and could ultimately encourage its management.info:eu-repo/semantics/publishedVersio

The Potential of Tree and Shrub Legumes in Agroforestry Systems

Climate variability and changes are utmost important primary drivers of biological processes. They are intimately associated with a wide array of abiotic stresses, highlighting the vulnerability of ecosystems and endangering biodiversity. Nitrogen‐fixing trees and shrubs (NFTSs) constitute a unique group of plants for their wide range of applications at the environmental, social and economic levels. In this chapter, we review and analyse the potential of this group of legumes in agroforestry towards sustainable agriculture in Africa. In the first part, the intertwined pillar of sustainable agriculture is brought forward under the context of growing population and climate changes. The second part addresses general aspects of legumes, including botany and the symbiosis with rhizobia. The third part includes the application of NFTS as N‐fertilizers in agroforestry, highlighting the importance of an accurate choice of the crop(s)/NFTS combination(s) and cropping type (intercropping, multistrata or fallows). The implementation of agroforestry systems with NFTS should be supported by fundamental research strategies such as stable isotopes and systems biology and preceded by experimental assays, in order to identify the factors promoting N‐losses and to design appropriate management strategies that synchronize legume‐N availability with the crop demand

Differential Impact of the Pinewood Nematode on Pinus Species Under Drought Conditions

The pinewood nematode (PWN), Bursaphelenchus xylophilus, responsible for the pine wilt disease (PWD), is a major threat to pine forests worldwide. Since forest mortality due to PWN might be exacerbated by climate, the concerns regarding PWD in the Mediterranean region are further emphasized by the projected scenarios of more drought events and higher temperatures. In this context, it is essential to better understand the pine species vulnerability to PWN under these conditions. To achieve that, physiological responses and wilting symptoms were monitored in artificially inoculated Pinus pinaster (P. pinaster), Pinus pinea (P. pinea), and Pinus radiata (P. radiata) saplings under controlled temperature (25/30°C) and water availability (watered/water stressed). The results obtained showed that the impact of PWN is species-dependent, being infected P. pinaster and P. radiata more prone to physiological and morphological damage than P. pinea. For the more susceptible species (P. pinaster and P. radiata), the presence of the nematode was the main driver of photosynthetic responses, regardless of their temperature or water regime conditions. Nevertheless, water potential was revealed to be highly affected by the synergy of PWN and the studied abiotic conditions, with higher temperatures (P. pinaster) or water limitation (P. radiata) increasing the impact of nematodes on trees' water status. Furthermore, water limitation had an influence on nematodes density and its allocation on trees' structures, with P. pinaster revealing the highest nematode abundance and inner dispersion. In inoculated P. pinea individuals, nematodes' population decreased significantly, emphasizing this species resistance to PWN. Our findings revealed a synergistic impact of PWN infection and stressful environmental conditions, particularly on the water status of P. pinaster and P. radiata, triggering disease symptoms and mortality of these species. Our results suggest that predicted drought conditions might facilitate proliferation and exacerbate the impact of PWN on these two species, through xylem cavitation, leading to strong changes in pine forests of the Mediterranean regions

Water isotopes in desiccating lichens

The stable isotopic composition of water is routinely used as a tracer to study water exchange processes in vascular plants and ecosystems. To date, no study has focussed on isotope processes in non-vascular, poikilohydric organisms such as lichens and bryophytes. To understand basic isotope exchange processes of non-vascular plants, thallus water isotopic composition was studied in various green-algal lichens exposed to desiccation. The study indicates that lichens equilibrate with the isotopic composition of surrounding water vapour. A model was developed as a proof of concept that accounts for the specific water relations of these poikilohydric organisms. The approach incorporates first their variable thallus water potential and second a compartmentation of the thallus water into two isotopically distinct but connected water pools. Moreover, the results represent first steps towards the development of poikilohydric organisms as a recorder of ambient vapour isotopic composition

Mapping and assessment of forest ecosystems and their services - Applications and guidance for decision making in the framework of MAES

The aim of this report is to illustrate by means of a series of case studies the implementation of mapping and assessment of forest ecosystem services in different contexts and geographical levels. Methodological aspects, data issues, approaches, limitations, gaps and further steps for improvement are analysed for providing good practices and decision making guidance. The EU initiative on Mapping and Assessment of the state of Ecosystems and their Services (MAES), with the support of all Member States, contributes to improve the knowledge on ecosystem services. MAES is one of the building-block initiatives supporting the EU Biodiversity Strategy to 2020.JRC.H.3-Forest Resources and Climat