Low precipitation due to climate change consistently reduces multifunctionality of urban grasslands in mesocosms

Urban grasslands are crucial for biodiversity and ecosystem services in cities, while little is known about their multifunctionality under climate change. Thus, we investigated the effects of simulated climate change, i.e., increased [CO2] and temperature, and reduced precipitation, on individual functions and overall multifunctionality in mesocosm grasslands sown with forbs and grasses in four different proportions aiming at mimicking road verge grassland patches. Climate change scenarios RCP2.6 (control) and RCP8.5 (worst-case) were simulated in walk-in climate chambers of an ecotron facility, and watering was manipulated for normal vs. reduced precipitation. We measured eight indicator variables of ecosystem functions based on below- and aboveground characteristics. The young grassland communities responded to higher [CO2] and warmer conditions with increased vegetation cover, height, flower production, and soil respiration. Lower precipitation affected carbon cycling in the ecosystem by reducing biomass production and soil respiration. In turn, the water regulation capacity of the grasslands depended on precipitation interacting with climate change scenario, given the enhanced water efficiency resulting from increased [CO2] under RCP8.5. Multifunctionality was negatively affected by reduced precipitation, especially under RCP2.6. Trade-offs arose among single functions that performed best in either grass- or forb-dominated grasslands. Grasslands with an even ratio of plant functional types coped better with climate change and thus are good options for increasing the benefits of urban green infrastructure. Overall, the study provides experimental evidence of the effects of climate change on the functionality of urban ecosystems. Designing the composition of urban grasslands based on ecological theory may increase their resilience to global change.publishedVersio

LCA of PHA Production – Identifying the Ecological Potential of Bio-plastic

A major reason for the call to increasingly switch towards polymers based on renewable resources is their presumed advantage regarding ecological performance compared to fossil competitors. Usually, this argument is based on the assumption that products based on renewable sources hold an inherent ecological advantage over products derived from other sources, in particular fossil sources. This claim however must be substantiated by looking into the ecological impacts accrued by the production of a material along the whole life cycle, from the raw material generation to the provision of the final product. Only thorough life cycle assessments (LCA) can provide solid, comprehensive and quantifiable information about the ecological performance of products, and thus answer the question of any superiority of bio-polymers regarding their environmental impacts. The paper will review the ongoing discourse about environmental performance of PHA in literature. It will also analyse the most important factors that decide about the ecological performance of PHA derived from different raw materials as well as the potential for improvement that is still available for PHA production

Stable crystalline lattices in two-dimensional binary mixtures of dipolar particles

The phase diagram of binary mixtures of particles interacting via a pair potential of parallel dipoles is computed at zero temperature as a function of composition and the ratio of their magnetic susceptibilities. Using lattice sums, a rich variety of different stable crystalline structures is identified including $A_mB_n$ structures. [$A$ $(B)$ particles correspond to large (small) dipolar moments.] Their elementary cells consist of triangular, square, rectangular or rhombic lattices of the $A$ particles with a basis comprising various structures of $A$ and $B$ particles. For small (dipolar) asymmetry there are intermediate $AB_2$ and $A_2B$ crystals besides the pure $A$ and $B$ triangular crystals. These structures are detectable in experiments on granular and colloidal matter.Comment: 6 pages - 2 figs - phase diagram update

Phylogenetic distance controls plant growth during early restoration of a semi-arid riparian forest

1. Little attention has been paid to phylogenetic diversity during restoration initiatives. Because plant phylogenetic distance can be a surrogate for functional diversity, its consideration could foster the restoration of degraded areas. 2. This study investigates the influence of species richness and phylogenetic relatedness during early restoration of a riparian forest located between the Atlantic Forest and semi-arid ecosystems in NE Brazil. The restoration experiment was established along a perennial stream in Monte Alegre, RN, investigating the significance of species richness and phylogenetic diversity for sapling survival and growth of the restored communities. 3. We used phylogenetic information on 47 tree species naturally occurring at the study site. The resulting phylogenetic tree had a basal node with three major clades. To implement the experiment, three species from each clade were randomly selected, resulting in nine species (from five families). We defined five levels of diversity: (i) no planting, (ii) monoculture, (iii) three phylogenetically related species (same clade), (iv) three phylogenetically distant species (different clades) and (v) nine species. The experiment consisted of 96 (12 m × 10 m) plots established along the two margins of the stream. Overall, 1656 saplings (20–50 cm) were planted in September 2015 (184 per species). We tested whether the survival and growth of saplings are influenced by the number of species planted and phylogenetic distance among them. 4. We assessed plant mortality and growth during two consecutive years (2016 and 2017). Survival was lower but relative growth was higher for plants near the stream. After controlling for differences in initial size, plots with phylogenetically distant species produced significantly taller plants, but only when occurring near the stream. Diversity treatments did not influence plant survival, while initial size determined plant survival and growth. 5. Our findings show that greater phylogenetic distance led to increased plant growth, probably, because of the presence of functionally divergent species that use resources in a complementary way. Therefore, plant phylogenetic relatedness should be considered during the design of restored communities to improve the outcomes of future restoration initiatives.Phylogenetic distance controls plant growth during early restoration of a semi-arid riparian forestpublishedVersio

Bagelen onder het bestuur van Soerakarta en Djokjokarta

Bij eenige hoofden in deze residentie, die het bestuur van Soerakarta en Djokjokarta over Bagelen beleefd en daarin een rol gespeeld hebben, heb ik omtrent dat bestuur een naauwgezet onderzoek gedaan. ..

Solving the multi-country Real Business Cycle model using a perturbation method

This paper solves the multi-country RBC model described in den Haan et al. (this issue) and Juillard and Villemot (this issue), using a perturbation method. We explain how to apply first- and second-order versions of the gensys2.m algorithm to this model. The perturbation method is computationally cheap and can easily be applied to large models with possibly hundreds of state variables. © 2010 Elsevier B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Reconciling the control of the native invasive Jacobaea aquatica and ecosystem multifunctionality in wet grasslands

Grasslands are managed to provide multiple goods and services. During recent decades, abandonment of marginal grasslands and intensification of the most productive sites resulted in biodiversity losses and reduced ecosystem services (ESs). Moreover, invasion by unwanted plants impaired ESs, as seen in Jacobaea aquatica, a poisonous native invader in pre-alpine grasslands of Central Europe. Invasion by this plant compromises fodder quality and endangers animal health, resulting in abandonment of grassland use. We tested different management regimes to reduce J. aquatica in wet grasslands of Southern Germany and assessed how its regulation affects grassland multifunctionality. We monitored indicators associated with productivity and conservation, such as the abundance of J. aquatica, forage quality, yield, abundance of specialists, and pollinator-relevant plants. Intensive management favoured multifunctionality by promoting productivity and biodiversity, yet also increasing the abundance of J. aquatica. Reduced management regulates J. aquatica cover close to an acceptable threshold while also reducing ESs. Thus, we conclude that moderate management strikes a balance between the control of the poisonous plant and the supply of grassland multifunctionality.publishedVersio

The quasi-cylindrical description of submerged laminar swirling jets

TThe quasi-cylindrical approximation is used to describe numerically the structure of a submerged swirling jet for subcritical values of the swirl ratio S<Sc . The emerging flow structure is affected by the swirling motion, which enhances the entrainment rate of the jet and induces an adverse pressure gradient that reduces its momentum flux. The effect is more pronounced as the swirl ratio S is increased, yielding for sufficiently large values of S a jet with an annular structure. The integration describes the smooth transition towards the far-field self-similar solution for all values of S smaller than a critical value S5Sc , at which the numerical integration fails to converge at a given downstream location. The comparisons with previous experimental results confirm the correspondence between the onset of vortex breakdown and the failure of the quasi-cylindrical approximation