Climate change and extreme weather events affect plants and animals and the direct impact of anthropogenic climate change has been documented extensively over the past years. In this review, I ...address the main consequences of elevated CO2 and O3 concentrations, elevated temperature and changes in rainfall patterns on the interactions between insects and their host plants. Because of their tight relationship with host plants, insect herbivores are expected to suffer direct and indirect effects of climate change through the changes experienced by their host plants, with consequences to population dynamics, community structure and ecosystem functioning.
•Comparative spatio-temporal analysis of nine different soil moisture datasets.•Negative linear variability to mean soil moisture relationships for all datasets.•Three groups of datasets with similar ...sill and range values from geostatistics.•Multifractal behavior of all datasets, showing at least one scale break.•Scale breaks associated with landuse structure, topography and soil type.
Soil moisture is a key variable in hydrology, meteorology and agriculture. It is influenced by many factors, such as topography, soil properties, vegetation type, management, and meteorological conditions. The role of these factors in controlling the spatial patterns and temporal dynamics is often not well known. The aim of the current study is to analyze spatio-temporal soil moisture patterns acquired across a variety of land use types, on different spatial scales (plot to meso-scale catchment) and with different methods (point measurements, remote sensing, and modeling). We apply a uniform set of tools to determine method specific effects, as well as site and scale specific controlling factors. Spatial patterns of soil moisture and their temporal development were analyzed using nine different datasets from the Rur catchment in Western Germany. For all datasets we found negative linear relationships between the coefficient of variation and the mean soil moisture, indicating lower spatial variability at higher mean soil moisture. For a forest sub-catchment compared to cropped areas, the offset of this relationship was larger, with generally larger variability at similar mean soil moisture values. Using a geostatistical analysis of the soil moisture patterns we identified three groups of datasets with similar values for sill and range of the theoretical variogram: (i) modeled and measured datasets from the forest sub-catchment (patterns mainly influenced by soil properties and topography), (ii) remotely sensed datasets from the cropped part of the Rur catchment (patterns mainly influenced by the land-use structure of the cropped area), and (iii) modeled datasets from the cropped part of the Rur catchment (patterns mainly influenced by large scale variability of soil properties). A fractal analysis revealed that all analyzed soil moisture patterns showed a multifractal behavior, with at least one scale break and generally high fractal dimensions. Corresponding scale breaks were found between different datasets. The factors causing these scale breaks are consistent with the findings of the geostatistical analysis. Furthermore, the joined analysis of the different datasets showed that small differences in soil moisture dynamics, especially at the upper and lower bounds of soil moisture (at maximum porosity and wilting point of the soils) can have a large influence on the soil moisture patterns and their autocorrelation structure. Depending on the prevalent type of land use and the time of year, vegetation causes a decrease or an increase of spatial variability in the soil moisture pattern.
In this study, we evaluated variation in vegetative and reproductive phenological events of four phylogenetically related plant species subjected to a seasonal environment. To this aim, we sampled 15 ...individuals of each plant species every fortnight for one year, between January and December of 2017. To assess when a given phenophase occurred more intensely in the population, the Fournier intensity index was used and the synchrony of individuals of the sample in a given phenological event was estimated using the activity index. The Rayleigh (Z) test was used to determine whether the phenological events have seasonal distribution. The relationship of abiotic factors (photoperiod, precipitation, relative humidity and temperature) with the intensity of phenophases was evaluated for each plant species using generalized linear models (GLMs). The phenophases of all plants showed a seasonal distribution pattern, as well as variation in synchrony of phenophases and specific sets of abiotic factors significantly influenced their phenophases. New leaves, for example, were produced throughout the seasons, with intense leaf fall in the dry season. Flowering periods, on the other hand, did not overlap. Indeed, species exhibited sequential flowering and asynchronous flowering among individuals. Our results suggest that the phenological patterns of four sympatric plant species are directly linked to climatic variables, but different abiotic factors affected different phenophases.
Amelioration of harsh conditions, manipulation of host plant quality, and protection from natural enemies have all been suggested as potential forces in the evolution and maintenance of concealed ...feeding in insects. The construction of shelters—either in the form of mines, galls, and leaf rolls—are expected to increase larval survivorship and might influence other organisms of the community through non-trophic direct and indirect effects when shelters are co-occupied or occupied after abandonment, placing leaf and stem shelter-builders within the context of ecosystem engineering. In this review, we evaluate the potential of shelter built by insects to reduce pressure exerted by natural enemies, increase tissue quality, and provide shelter against abiotic conditions experienced during insect development. Through a quantitative analysis, we also examined the effects of insect shelters on patterns of richness and abundance of local communities, reviewing the data published in the last 15 years. We demonstrate strong effects of shelters on several arthropods, with increased richness and abundance when shelters are present in the host plants. These results reinforce the importance of the physical structures created by insects that although subtle, might have important roles in facilitative interactions.
Fast pyrolysis of heavy metal contaminated willow, with high concentrations of Cd, Cu, Pb and Zn, resulting from phytoremediation, is investigated. The distribution of the heavy metals depends on the ...plant part (leaves and branches). Nevertheless, their individual pyrolysis fractions (at an operational temperature of 623
K), i.e., bio-oil/tar and gas, are both heavy metal free. Some small differences in the kind and amounts of the organic compounds are found in the bio-oil and gaseous fraction. In view of practical considerations leaves and branches should nevertheless be pyrolysed simultaneously. The use of hyphenated thermal analytical techniques allows obtaining more detailed information on the compositional features of the pyrolysis fraction.
High amounts of water present in bio-oil are one of the major drawbacks for its utilisation as a fuel. One technology that shows the potential to satisfy the demand for bio-oil with a reduced water ...content is the flash co-pyrolysis of biomass with polylactic acid, PLA. The influence of PLA on the pyrolysis of willow is investigated with a semi-continuous home-built pyrolysis reactor. Flash co-pyrolysis of willow/PLA blends (10:1, 3:1, 1:1 and 1:2) show synergetic interaction. A higher bio-oil yield and a lower water content as a function of the willow/PLA ratios are obtained. Among the tested blends, the 1:2 willow/PLA blend shows the most pronounced synergy: a reduction in the production of pyrolytic water of almost 28%, accompanied by an increase of more than 37% in the production of water-free bio-oil. Additionally, PLA shows to have a positive influence on the energetic value of the bio-oil produced and on the resulting energy recuperation.
The structure of the community of insect herbivores in a plant can be determined by plant traits and also by interactions with consumers. We studied the herbivores associated with the tropical plant
...Andira nitida
(Fabaceae), aiming to understand the temporal co-occurrence of herbivore insects from different guilds. We monitored and quantified the temporal sequence of appearance and leaf consumption of three herbivore guilds (leaf miners, gall-formers and chewers) at weekly intervals for 23 weeks (between September 2021 and March 2022), testing whether functional leaf traits (leaf area, leaf dry matter content, specific leaf area and leaf age) influence herbivory incidence and intensity. Leaves of
A. nitida
showed simultaneous damage by miners, chewers and six gall species. We found a temporal sequence in the establishment of leaf herbivores and a preference for young leaves. However, null model analysis indicated independent patterns of association between herbivores, and there was no evidence of co-occurrence or repulsion between herbivores or herbivore guilds. We found that leaf age is a determinant functional trait for the occurrence of all guilds and types of herbivores in
A. nitida
. However most of the physical characteristics of the leaf did not show a clear effect on the herbivore community. We showed that interactions among herbivores partially explained the organization of herbivorous insects in
A. nitida
and that patterns of occurrence depend more on the life history of herbivores than on aspects associated with plant functional traits. We suggest that there is differential leaf use by herbivores in time, which leads to the formation of different pairs of co-occurring herbivores.
The disposal problem associated with phytoextraction of farmland polluted with heavy metals by means of willow requires a biomass conversion technique which meets both ecological and economical ...needs. Combustion and gasification of willow require special and costly flue gas treatment to avoid re-emission of the metals in the atmosphere, whereas flash pyrolysis mainly results in the production of (almost) metal free bio-oil with a relatively high water content. Flash co-pyrolysis of biomass and waste of biopolymers synergistically improves the characteristics of the pyrolysis process: e.g. reduction of the water content of the bio-oil, more bio-oil and less char production and an increase of the HHV of the oil. This research paper investigates the economic consequences of the synergistic effects of flash co-pyrolysis of 1:1 w/w ratio blends of willow and different biopolymer waste streams via cost-benefit analysis and Monte Carlo simulations taking into account uncertainties. In all cases economic opportunities of flash co-pyrolysis of biomass with biopolymer waste are improved compared to flash pyrolysis of pure willow. Of all the biopolymers under investigation, polyhydroxybutyrate (PHB) is the most promising, followed by Eastar, Biopearls, potato starch, polylactic acid (PLA), corn starch and Solanyl in order of decreasing profits. Taking into account uncertainties, flash co-pyrolysis is expected to be cheaper than composting biopolymer waste streams, except for corn starch. If uncertainty increases, composting also becomes more interesting than flash co-pyrolysis for waste of Solanyl. If the investment expenditure is 15% higher in practice than estimated, the preference for flash co-pyrolysis compared to composting biopolymer waste becomes less clear. Only when the system of green current certificates is dismissed, composting clearly is a much cheaper processing technique for disposing of biopolymer waste.
CEO compensation that is perceived to be excessive regularly causes agitation in the population. Using German data, we show that perceiving CEO pay to be unfair has economic repercussions in terms of ...lower work morale.
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