Washboarding: Are Man-Managed Honeybees Performing a Vestigial Activity Fostered by Cryptogams?

A common view is that honeybees are mostly managed by beekeepers for commercial purposes or as a hobby, especially in Europe. This misconception is probably due to the lack of systematic studies on wild colonies of honeybees in Europe in comparison to other regions of the world. Since we are used to considering this species as “domesticated”, we may be induced to disregard activities not distinctly linked with colony survival, reproduction, or productivity. Washboarding is one of them in which the entire colony stops resource collection activities; numerous individual bees assemble on the front side of the hive and perform repetitive movements back and forth. They are curiously synchronised but apparently without a scope. In this exploratory work, we carried out a literature review of available, mostly grey, literature. Assuming this behaviour may be linked to cavity-nesting and to tree trunks or rocks being rough surfaces hosting various cryptogams, we performed preliminary observations and manipulative experiments. From our survey, we depict that washboarding is frequently reported in grey literature/beekeepers’ reports, but rarely mentioned in scientific literature. Beekeepers who responded to a designed questionnaire observed this behaviour in various ecological situations, with no trend emerging. Our preliminary experiment of placing cryptogams in front of managed hives resulted in honeybees removing lichens (foliose types) or covering with propolis, and all species were affected. Further research is needed to clarify if lichens are removed because of their chemical compounds, because of hosting potentially toxic microorganisms, or collected as resourcesinfo:eu-repo/semantics/publishedVersio

Winter collection of the underutilized berry Corema album (L.): New insights on its maturation progression

Increasing interest in Corema album L. is raising due to the appealing white colour and potential health benefits related to its bioactive composition. White fruits production culminates in late August on coastal dunes, but fruits of various colours are present almost till flowering (late February). We undertook a preliminary physical-chemical characterisation (biometric, CIELab colour, pH, soluble solids content and titrable acidity) of a late fruit collection to disentangle maturity progression and to reveal latent qualities for future utilisation. Irrespective of fruit perceived colouration (white, translucent, brown, brown with black spots and black), the characterized high acidity (1-3 g.100 mL-1) is suggestive that over-mature fruits can still be further explored as food additives. Moreover, using a multivariate exploratory technique, we found a clear fruit’s maturation progression from white/translucent to black, a so-far unreported maturity stage. Addressing gaps in plant phenology and fruit’s maturity behaviour is needed before undertaking cultivation.info:eu-repo/semantics/publishedVersio

Editorial: The Green Side of the Water Cycle: New Advances in the Study of Plant Water Dynamics

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Differential response of two acidophytic lichens to increased reactive nitrogen availability

Lichens are one of the most responsive components of the ecosystem to reactive forms of nitrogen. In this work, we selected the lichen genera Cladonia and Usnea, composed of terricolous and epiphytic lichens respectively, and described as sensitive to nitrogen, to test the effects of different doses of nitrogen on lichen physiological parameters (photobiont and mycobiont vitality, chitin quantification, nitrogen content and stable isotopes analysis). The main objectives were to check if the activation of protective mechanisms could be stimulated in case of chronic stress (low nitrogen increase for prolonged time), and, if so, if a toxicity threshold could be identified above which these mechanisms fail. The two lichen genera were generally affected by prolonged exposure to increased nitrogen availability. However, Cladonia rangiformis was able to maintain physiological functioning at the lowest nitrogen doses used, whereas thalli of Usnea become overwhelmed. Moreover, the mycobiont appeared to be more sensitive than the photobiont responding to lower nitrogen doses. Although only studies of longer duration and testing more nitrogen doses will be able to determine an accurate toxicity threshold, these results give important clues on the use of lichens as biomonitors for the establishment of environmental policies.info:eu-repo/semantics/publishedVersio

Soil origin impacts Acacia longifolia above and belowground development: water and nutrition as players

Context: Acacia longifolia is an aggressive invader, disrupting habitats and communities worldwide. Understanding what drives its expansion is of paramount importance. Key functional traits include fast growth and the presence of bacterial symbionts performing nitrogen fixation. Aims: To address early plant development of A. longifolia under different soils and growth conditions (water and nutrition availability), establishing the key factors that influence above and belowground responses. Methods: Plants were grown in pots with soils collected from forest, agricultural and dune areas in relative proximity, in a controlled experiment designed to study water effect and nutrient availability on early growth. Growth parameters included shoot and root length, nodule number and weight. Bacteria were isolated from nodules for genetic diversity evaluation. Photosynthetic pigments and isotopic nitrogen and carbon analyses were performed to address nitrogen fixation and photosynthesis. Key results: Soil origin influenced plant growth and bacterial diversity. Largest plant development was achieved in forest soils with added nutrition and water. Plants from agricultural soil displayed higher aboveground development; however, belowground nodule number and bacterial biodiversity decreased, possibly due to anthropogenic activities. Forest soil promoted belowground development and bacterial diversity. In dune soils overall growth was lower and nitrogen fixation was higher. Conclusion: Abiotic factors influenced juvenile acacia development; nutrition acts as a growth enhancer, and soil origin, including its microbial communities, can be considered a development modulator. Bacterial diversity varied according to soil type. Implications: Several above and belowground interactions showed the need for an integrative perspective to understand acacias invasive potential.info:eu-repo/semantics/submittedVersio

From canopy to single flowers: a downscale approach to flowering of the invasive species Acacia longifolia

Context: Acacia longifolia is a native legume of south-eastern Australia and Tasmania and is invasive in many parts of the world. A key feature to its success is the production of a high quantity of flowers every season, resulting in a massive seedbank that remains dormant in the soil for decades. Many studies have been performed on this species’ reproductive biology, but none has focused on flowering in detail. Aims: Our main objective was to understand this species’ resource allocation strategy that ensures its successful reproduction in the invasive range. Methods: We developed an integrative approach, assessing flowering at different levels, namely, canopy and branch flowering (macro scale), downscaling to individual flower functional stages and their duration, pollen longevity and stigma receptivity (micro scale). We performed this study in three different locations in sand dunes along the Portuguese coast with different environmental conditions. Key results: Canopy flowering shows no difference among sites. Pollen and stigma assessment showed that this species is protogynous, with the stigma being highly receptive long before pollen is released. Once released, pollen lasts roughly 72 h. Individual flowers are relatively short-lived, with a rapid progression from closed flower buds to fully open flowers. Implications: Our results indicated that A. longifolia has a resource trade-off strategy of investing in flowers and pollen that are relatively short-lived, which are counterbalanced by their massive quantities.info:eu-repo/semantics/acceptedVersio

The distribution of the invasive Acacia longifolia shows an expansion towards southern latitudes in South America

Contemporary climate change, in particular higher temperatures, may greatly enhance the expansion of invasive species. Acacia longifolia (Fabaceae, subgenus Phyllodineae) is a native species of Southeast Australia and Tasmania, invasive in South Africa, Mediterranean Europe and South America. According to several records, this species has been introduced in Southern Brazil and Uruguay for fixation of dunes and for ornamental purposes in the mid-20th century and has since then caused several environmental and socio-economic problems. However, its current distribution in these south American countries is undocumented, as well as the types of habitats it has invaded since its introduction. In this context, during May 2019 we performed a study through a latitudinal and climatic gradient along the coast, from southern Brazil (Santa Catarina and Rio Grande do Sul states) to Uruguay, to evaluate the presence of A. longifolia taking into consideration previous records of this species. Our observations showed an increase in tree density along the coast, from Brazil to Uruguay, with a clear distribution southward. It was not possible to confirm earlier observations of this species in southern Brazil (with the exception of Florianópolis), which may be associated with changes in temperature and precipitation in this region.info:eu-repo/semantics/publishedVersio

Acacia longifolia: A Host of Many Guests Even after Fire

Acacia longifolia is a worldwide invader that cause damage in ecosystems, expanding largely after wildfires, which promote germination of a massive seed bank. As a legume, symbiosis is determinant for adaptation. Our study aims to isolate a wider consortium of bacteria harboured in nodules, including both nitrogen and non-nitrogen fixers. Furthermore, we aim to evaluate the e ects of fire in nodulation and bacterial diversity on young acacias growing in unburnt and burnt zones, one year after the fire. For this, we used molecular approaches, M13 fingerprinting and 16S rRNA partial sequencing, to identify species/genera involved and 15N isotopic composition in leaves and plant nodules. Nitrogen isotopic analyses in leaves suggest that in unburnt zones, nitrogen fixation contributes more to plant nitrogen content. Overall, A. longifolia seems to be promiscuous and despite Bradyrhizobium spp. dominance, Paraburkholderia spp. followed by Pseudomonas spp. was also found. Several species not previously reported as nitrogen-fixers were identified, proposing other functions besides ammonia acquisition. Our study shows that bacterial communities are di erent in nodules after fire. Fire seems to potentiate nodulation and drives symbiosis towards nitrogen-fixers. Taken together, a multifunctional community inside nodules is pointed out which potentiate A. longifolia invasiveness and adaptation.info:eu-repo/semantics/publishedVersio

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

Using nitrogen concentration and isotopic composition in lichens to spatially assess the relative contribution of atmospheric nitrogen sources in complex landscapes

Reactive nitrogen (Nr) is an important driver of global change, causing alterations in ecosystem biodiversity and functionality. Environmental assessments require monitoring the emission and deposition of both the amount and types of Nr. This is especially important in heterogeneous landscapes, as different land-cover types emit particular forms of Nr to the atmosphere, which can impact ecosystems distinctively. Such assessments require high spatial resolution maps that also integrate temporal variations, and can only be feasibly achieved by using ecological indicators. Our aim was to rank land-cover types according to the amount and form of emitted atmospheric Nr in a complex landscape with multiple sources of N. To do so, we measured and mapped nitrogen concentration and isotopic composition in lichen thalli, which we then related to land-cover data. Results suggested that, at the landscape scale, intensive agriculture and urban areas were the most important sources of Nr to the atmosphere. Additionally, the ocean greatly influences Nr in land, by providing air with low Nr concentration and a unique isotopic composition. These results have important consequences for managing air pollution at the regional level, as they provide critical information for modeling Nr emission and deposition across regional as well as continental scales.Supported by project GISA (funded by private companies: GALP, Repsol, APS, AdSA, AICEP, CARBOGAL, EDP, EuroResinas, KIMAXTRA, REN and GENERG; and managed by local authorities: CCDRA, ARSA and Municipalities of Sines, Santiago do Cacém, Grândola, Álcacer do Sal and Odemira. Further support for researchers from FCT-MCTES (SFRH/BPD/75425/2010, SFRH/BPD/109382/2015 and Investigador FCT contract) and EC-H2020 (NitroPortugal 692331)