Assessment of environmental risk areas based on airborne pollen patterns as a response to land use and land cover distribution

Allergic respiratory diseases are considered to be among the most important public health concerns, and pollen is the main cause of allergic respiratory diseases worldwide. However, the biological component of air quality is largely underestimated, and there is an important gap in the legislation in this area. The aims of this study were to characterise the occurrence and incidence of pollen exposure in relation to potential pollen sources and to delineate the main areas of aerobiological risk in the Madrid Autonomous Region based on homogeneous patterns of pollen exposure. This study uses the historical aerobiological database of the Madrid Region Palynological Network (central Spain) from ten pollen stations from 1994 to 2022, and the land-use information from the Corine Land Cover. Multiple clustering approaches were followed to group the sampling stations and subsequently all the 1 × 1km pixels for the Madrid Autonomous Region. The clustering dendrogram for land-use distribution was compared to the dendrogram for historical airborne pollen data. The two dendrograms showed a good alignment with a very high correlation (0.95) and very low entanglement (0.15), which indicates a close correspondence between the distribution of the potential pollen sources and the airborne pollen dynamics. Based on this knowledge, the Madrid Autonomous Region was divided into six aerobiological risk areas following a clear anthropogenic gradient in terms of the potential pollen sources that determine pollen exposure in the Madrid Region. Spatial regionalisation is a common practice in environmental risk assessment to improve the application of management plans and optimise the air quality monitoring networks. The risk areas proposed by scientific criteria in the Madrid Autonomous Region can be adjusted to other operational criteria following a framework equivalent to other air quality networks.

The phenological response of European vegetation to urbanisation is mediated by macrobioclimatic factors

Plant phenology is a crucial component of ecosystem functioning and is affected by multiple elements of global change; we therefore need to quantify the current phenological changes associated to human activities and understand their impacts on ecosystems. Urbanisation and the intensification of anthropogenic activities alter meteorological conditions and cause phenological changes in urban vegetation worldwide. We used remote sensing data to evaluate the phenological response (start of season date SOS, length of season LOS and end of season date EOS) of five main vegetation types (evergreen forests, deciduous forests, mixed forests, sparse woody vegetation and grasslands) to urbanisation in the 69 most populated pan-European metropolitan areas (i.e., those that include cities with a population over 450,000 inhabitants) for the period 2002-2021. In general, SOS advanced and LOS increased with urbanisation intensity across European metropolitan areas. We found that macrobioclimatic factors strongly determined the strength and direction of the phenological response to urbanisation intensity. The greatest advances in SOS with increasing urbanisation were registered in metropolitan areas in the Mediterranean region, where there was also more uncertainty in this relationship. The EOS advanced with urbanisation in metropolitan areas in the Mediterranean macrobioclimate, whereas in areas with higher precipitation during summer the opposite trend was observed suggesting water availability mediates the response between urbanisation and autumn phenophases. Our results suggest that macrobioclimatic constraints operating at the continental scale are crucial to understand the relationship between plant phenology and urbanisation intensity.

Linking functional composition moments of the sub-Mediterranean ecotone with environmental drivers

Introduction

Functional trait-based approaches are extensively applied to the study of mechanisms governing community assembly along environmental gradients. These approaches have been classically based on studying differences in mean values among species, but there is increasing recognition that alternative metrics of trait distributions should be considered to decipher the mechanisms determining community assembly and species coexistence. Under this framework, the main aim of this study is to unravel the effects of environmental conditions as drivers of plant community assembly in sub-Mediterranean ecotones.

Methods

We set 60 plots in six plant communities of a sub-Mediterranean forest in Central Spain, and measured key above- and belowground functional traits in 411 individuals belonging to 19 species, along with abiotic variables. We calculated community-weighted mean (CWM), skewness (CWS) and kurtosis (CWK) of three plant dimensions, and used maximum likelihood techniques to analyze how variation in these functional community traits was driven by abiotic factors. Additionally, we estimated the relative contribution of intraspecific trait variability and species turnover to variation in CWM.

Results and discussion

The first three axes of variation of the principal component analyses were related to three main plant ecological dimensions: Leaf Economics Spectrum, Root Economics Spectrum and plant hydraulic architecture, respectively. Type of community was the most important factor determining differences in the functional structure among communities, as compared to the role of abiotic variables. We found strong differences among communities in their CWMs in line with their biogeographic origin (Eurosiberian vs Mediterranean), while differences in CWS and CWK indicate different trends in the functional structure among communities and the coexistence of different functional strategies, respectively. Moreover, changes in functional composition were primarily due to intraspecific variability.

Conclusion

We observed a high number of strategies in the forest with the different communities spreading along the acquisitive-conservative axis of resource-use, partly matching their Eurosiberian-Mediterranean nature, respectively. Intraspecific trait variability, rather than species turnover, stood as the most relevant factor when analyzing functional changes and assembly patterns among communities. Altogether, our data support the notion that ecotones are ecosystems where relatively minor environmental shifts may result in changes in plant and functional composition.

Living at the edge: the functional niche occupation of woody plant communities in the submediterranean ecotone

BACKGROUND AND AIMS

Submediterranean areas are rich ecotones, where slight modifications in environmental conditions can lead to substantial changes in the composition of plant communities. They thus offer an ideal scenario to examine plant community assembly. In this study, we followed a trait-based approach including intraspecific variability to elucidate (1) the relationship between niche occupancy components and species richness, (2) the processes governing the assembly of these communities and (3) the contribution of intraspecific trait variability in shaping the functional trait space.

METHODS

We measured eight morphological and chemical traits in 405 individuals across 60 plots located in different forest communities (Mediterranean, Eurosiberian and Mixed) coexisting within a submediterranean ecosystem in central Spain. We calculated three niche occupancy components related to Hutchinson's n-dimensional hypervolumes: the total functional volume of the community, the functional overlap between species within the community and the average functional volume per species, and then used null models to explore the relative importance of habitat filtering, limiting similarity and intraspecific variability as assembly patterns.

KEY RESULTS

Both habitat filtering and niche differentiation drive the community assembly of Mediterranean communities, whereas limiting similarity and hierarchical competition shape Eurosiberian communities. Intraspecific responses were mostly explained by shifts in species niches across the functional space (changes in the position of the centroids of hypervolumes).

CONCLUSIONS

Different assembly mechanisms govern the structure of Mediterranean, Eurosiberian and Mixed plant communities. Combining niche occupancy components with a null model approach at different spatial scales offers new insights into the mechanisms driving plant community assembly. Consideration of intraspecific variability is key for understanding the mechanisms governing species coexistence in species-rich ecotones.

The Economics Spectrum Drives Root Trait Strategies in Mediterranean Vegetation

Extensive research efforts are devoted to understand fine root trait variation and to confirm the existence of a belowground root economics spectrum (RES) from acquisitive to conservative root strategies that is analogous to the leaf economics spectrum (LES). The economics spectrum implies a trade-off between maximizing resource acquisition and productivity or maximizing resource conservation and longevity; however, this theoretical framework still remains controversial for roots. We compiled a database of 320 Mediterranean woody and herbaceous species to critically assess if the classic economics spectrum theory can be broadly extended to roots. Fine roots displayed a wide diversity of forms and properties in Mediterranean vegetation, resulting in a multidimensional trait space. The main trend of variation in this multidimensional root space is analogous to the main axis of LES, while the second trend of variation is partially determined by an anatomical trade-off between tissue density and diameter. Specific root area (SRA) is the main trait explaining species distribution along the RES, regardless of the selected traits. We advocate for the need to unify and standardize the criteria and approaches used within the economics framework between leaves and roots, for the sake of theoretical consistency.

Theoretical characterization of triangular CdS nanocrystals: a tight-binding approach

We provide theoretical modeling of the optical spectrum of recently synthesized triangular CdS nanocrystals by means of atomistic tight-binding theory. Both zinc blende and wurtzite structures are considered. Optical properties predicted for triangular prisms are very different from the ones obtained for tetrahedral quantum dots when z-polarized light is employed. In particular, the ground transition is dim for triangular prisms, whereas it is bright and highly intense for tetrahedra. The high sensitivity of the fine optical properties on the quantum dot shape allows us to discriminate between truncated tetrahedra and triangular prisms and also to estimate the thickness of the nanocrystals.

Alkaloids from Delphinium staphisagria

Three new diterpenoid alkaloids, isoazitine (1), 19-oxodihydroatisine (2), and 22-O-acetyl-19-oxodihydroatisine (3), and eight known alkaloids-azitine (4), dihydroatisine (5), delphinine, neoline, bullatine C (14-acetylneoline), chasmanine, 14-acetylchasmanine, and the quaternary base atisinium chloride (7)-were isolated from the aerial parts of Delphinium staphisagria. Structures of the new alkaloids were established mainly by 1D and 2D NMR spectroscopy, including (1)H COSY, HMQC, HMBC, and ROESY. The (1)H and (13)C NMR data for alkaloids 4 and 5 are also reported.

Sesquiterpene lactones and other constituents of Centaurea napifolia

Aerial parts of Centaurea napifolia furnished the sesquiterpene lactones cnicin, 4'-acetoxycnicin, melitensin, dehydromelitensin, two known esters of dehydromelitensin, lappaol and a lappaol isomer, and a 1,2-diacylated glucose.

Antinociceptive, anti-inflammatory and antipyretic effects of lapidin, a bicyclic sesquiterpene

Lapidin, a bicyclic sesquiterpene from Ferula linkii Webb, has been evaluated for antinociceptive, anti-inflammatory, and antipyretic activities in mice and rats. Lapidin, vehicle, or the appropriate reference analgesic and anti-inflammatory compounds (acetylsalicylic acid [ASA] and indomethacin) were injected i.p. The more conspicuous effects of lapidin were: 1) a significant protective effect (17-62%; 2.5-20 mg/kg) towards writhings and stretchings induced by acetic acid in mice; 2) a significant antinociceptive effect on jumping responses in the hot-plate test (120 seconds at 15 mg/kg vs. 40 and 85 seconds in vehicle and ASA-treated mice, respectively); 3) a significant dose-dependent (5-15 mg/kg) antinociceptive effect against mechanical noxious stimuli; 4) a dose-dependent anti-inflammatory effect in the carrageenan-induced edema which, at the higher dose (20 mg/kg), was comparable (65% inhibition of paw swelling at 3 hours) to that obtained after indomethacin (10 mg/kg); and 5) a moderate antipyretic effect against yeast-induced hyperthermia. Present results demonstrate that lapidin possesses antinociceptive, anti-inflammatory, and less pronounced antipyretic effects comparable to those of classical non-steroid anti-inflammatory drugs, which make it worthy of further investigations as an antinociceptive and anti-inflammatory drug.