Sweet flowers are slow and weeds make haste: anthropogenic dispersal of plants via garden and construction soil

This is the final version of the article. Available from Oxford University Press via the DOI in this record.Anthropogenic activities are increasingly responsible for the dispersal of plants. Of particular concern is anthropogenic dispersal of problematic invasive non-native plants. A common dispersal vector is the movement of soil containing seeds or rhizomes. Housing development and domestic gardening activities cause large quantities of soil to be moved, and understanding the role of these activities is critical for informing policy and management to reduce the spread of problematic plants. Here, by collecting soil samples being moved for housing development and domestic gardening, and observing the species that germinated from these samples, we determined the quantities and invasive status of plants moved. From our samples nearly 2000 individuals representing 90 species germinated. Our results suggest that given the quantity of topsoil needed to cover an average-sized UK garden (190 m2 ), there could be 2.2 million and c.2 million viable seeds in soil sourced from housing developments and gardens, respectively. In both housing development and garden samples, native species were more abundant and species-rich than non-native naturalised and invasive species. Buddleia (an invasive) was the most common species overall and in garden samples; this is likely due to multiple traits that adapt it to dispersal, such as prolific seed production. The abundance of invasive and naturalised species was significantly higher in garden than in housing development samples, suggesting that informal movement of soil between gardens poses a greater risk of spreading invasive plants than commercial sources. Consequences for models predicting future distributions of plants, and strategies to mitigate anthropogenic dispersal of problematic plants are considered.This project was funded by the University of Exeter and the Animal and Plant Health Agency. We are grateful to all who gave samples for this study

Unsung heroes: Constituency election agents in British general elections

Despite their central role in the electoral process, constituency agents have been largely overlooked by political scientists and this article seeks to rectify the omission. It sketches the origins and development of the role of agent from the late 19th century and suggests that a serious rethink of the role took place in the 1990s. Survey-based evidence about the social characteristics of agents is presented confirming that they are largely middle-aged, middle-class, well-educated men. They are also becoming more experienced, offer realistic assessments of the impact of constituency campaigning and, arguably, many take a long-term view of how their party's support can be maximised

Optical Modelling and Phylogenetic Analysis Provide Clues to the Likely Function of Corneal Nipple Arrays in Butterflies and Moths.

This is the final version. Available from MDPI via the DOI in this recordThe lenses in compound eyes of butterflies and moths contain an array of nipple-shaped protuberances, or corneal nipples. Previous work has suggested that these nipples increase light transmittance and reduce the eye glare of moths that are inactive during the day. This work builds on but goes further than earlier analyses suggesting a functional role for these structures including, for the first time, an explanation of why moths are attracted to UV light. Using a phylogenetic approach and 3D optical modelling, we show empirically that these arrays have been independently lost from different groups of moths and butterflies and vary within families. We find differences in the shape of nipples between nocturnal and diurnal species, and that anti-glow reflectance levels are different at different wave-lengths, a result thereby contradicting the currently accepted theory of eye glow for predator avoidance. We find that there is reduced reflectance, and hence greater photon absorption, at UV light, which is probably a reason why moths are attracted to UV. We note that the effective refractive index at the end of the nipples is very close to the refractive index of water, allowing almost all the species with nipples to see without distortion when the eye is partially or completely wet and providing the potential to keep eyes dry. These observations provide a functional explanation for these arrays. Of special interest is the finding that their repeated and independent loss across lepidopteran phylogeny is inconsistent with the explanation that they are being lost in the 'higher', more active butterflies

Skewed contributions of individual trees to indirect nature experiences

This is the author accepted manuscript. Final version available from Elsevier via the DOI in this record.Exposure to nature is associated with a broad range of benefits to human health. Whilst there has been exploration of how these experiences vary amongst people, the converse – how different individual organisms contribute to human nature experiences – has largely been overlooked. The most common way that people experience nature occurs indirectly, when they are in a room with a natural view. Here, we estimate variation in how individual trees provide indirect nature experiences in an urban human population. As a proxy for its contribution towards indirect nature experiences, within an extended urban area in southern England, UK (n = 612,920) we calculated the number of buildings with line of sight to each tree. We then modelled each tree’s contribution towards these experiences against potential predictors, namely tree height, land ownership, social deprivation, while controlling for human population density. We demonstrate that a small number of trees contribute disproportionately towards indirect nature experiences, with individual trees in socio-economically deprived high density housing falling within the viewscape of significantly more buildings. Further, trees in private gardens were generally more important for providing indirect nature experiences than those in public green spaces. This novel study demonstrates the skewed contribution of different organisms to human population indirect nature experiences. This approach can be applied more broadly to understand how individual organisms provide indirect, incidental and intentional nature experiences. Understanding the ecology behind human nature experiences is an important step towards linking urban design and policy for maximising the health benefits from nature.Natural Environment Research Council (NERC

Unmanned aerial vehicle (UAV) derived structure-from-motion photogrammetry point clouds for oil palm (Elaeis guineensis) canopy segmentation and height estimation

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.The vast size of oil palm (Elaeis guineensis) plantations has led to lightweight unmanned aerial vehicles (UAVs) being identified as cost effective tools to generate inventories for improved plantation management, with proximal aerial data capable of resolving single palm canopies at potentially, centimetric resolution. If acquired with sufficient overlap, aerial data from UAVs can be processed within structure-from-motion (SfM) photogrammetry workflows to yield volumetric point cloud representations of the scene. Point cloud-derived structural information on individual palms can benefit not only plantation management but is also of great environmental research interest, given the potential to deliver spatially contiguous quantifications of aboveground biomass, from which carbon can be accounted. Using lightweight UAVs we captured data over plantation plots of varying ages (2, 7 and 10 years) at peat soil sites in Sarawak, Malaysia, and we explored the impact of changing spatial resolution and image overlap on spatially variable uncertainties in SfM derived point clouds for the ten year old plot. Point cloud precisions were found to be in the decimetre range (mean of 26.7 31 cm) for a 10 year old plantation plot surveyed at 100 m flight altitude and >75% image overlap. Derived canopy height models were used and evaluated for automated palm identification using local height maxima. Metrics such as maximum canopy height and stem height, derived from segmented single palm point clouds were tested relative to ground validation data. Local maximum identification performed best for palms which were taller than surrounding undergrowth but whose fronds did not overlap significantly (98.2% mapping accuracy for 7 year old plot of 776 palms). Stem heights could be predicted from point cloud derived metrics with root-mean-square errors (RMSEs) of 0.27 m (R2= 0.63) for 7 year old and 0.45 m (R2=0.69) for 10 year old palms. It was also found that an acquisition designed to yield the minimal required overlap between images (60%) performed almost as well as higher overlap acquisitions (>75%) for palm identification and basic height metrics which is promising for operational implementations seeking to maximise spatial coverage and minimise processing costs. We conclude that UAV-based SfM can provide reliable data not only for oil palm inventory generation but allows the retrieval of basic structural parameters which may enable per-palm above-ground biomass estimations.European CommissionMarie Skłodowska-Curi

Attention U-Net as a surrogate model for groundwater prediction

Numerical simulations of groundwater flow are used to analyze and predict the response of an aquifer system to its change in state by approximating the solution of the fundamental groundwater physical equations. The most used and classical methodologies, such as Finite Difference (FD) and Finite Element (FE) Methods, use iterative solvers which are associated with high computational cost. This study proposes a physics-based convolutional encoder-decoder neural network as a surrogate model to quickly calculate the response of the groundwater system. Holding strong promise in cross-domain mappings, encoder-decoder networks are applicable for learning complex input-output mappings of physical systems. This manuscript presents an Attention U-Net model that attempts to capture the fundamental input-output relations of the groundwater system and generates solutions of hydraulic head in the whole domain given a set of physical parameters and boundary conditions. The model accurately predicts the steady state response of a highly heterogeneous groundwater system given the locations and piezometric head of up to 3 wells as input. The network learns to pay attention only in the relevant parts of the domain and the generated hydraulic head field corresponds to the target samples in great detail. Even relative to coarse finite difference approximations the proposed model is shown to be significantly faster than a comparative state-of-the-art numerical solver, thus providing a base for further development of the presented networks as surrogate models for groundwater prediction

Image fusion of LM-MRI and MRA for endovascular interventions

Peripheral arterial occlusive disease can be treated with endovascular interventions. These interventions are currently intraoperatively guided by fluoroscopy. A possible alternative is LF-MRI, but the current image quality of low-field (LF) MRI may not be sufficient. The purpose of this study is to evaluate the possibility of image fusion of LF-MRI with preoperative MRA to improve the image quality. To test this, LF-MRI and 3T MRI images were made of a healthy test subject. These images were registrated using manual landmark detection. The result was a visually successful registration image of LF-MRI and anatomical MRI, which shows the possibility of manual image registration

Artificial nighttime light changes aphid-parasitoid population dynamics

This is the final version of the article. Available from Nature Publishing Group via the DOI in this record.Artificial light at night (ALAN) is recognized as a widespread and increasingly important anthropogenic environmental pressure on wild species and their interactions. Understanding of how these impacts translate into changes in population dynamics of communities with multiple trophic levels is, however, severely lacking. In an outdoor mesocosm experiment we tested the effect of ALAN on the population dynamics of a plant-aphid-parasitoid community with one plant species, three aphid species and their specialist parasitoids. The light treatment reduced the abundance of two aphid species by 20% over five generations, most likely as a consequence of bottom-up effects, with reductions in bean plant biomass being observed. For the aphid Megoura viciae this effect was reversed under autumn conditions with the light treatment promoting continuous reproduction through asexuals. All three parasitoid species were negatively affected by the light treatment, through reduced host numbers and we discuss induced possible behavioural changes. These results suggest that, in addition to direct impacts on species behaviour, the impacts of ALAN can cascade through food webs with potentially far reaching effects on the wider ecosystem.The research leading to this paper was funded by the European Research council under the European Union’s Seventh Framework programme (FP7/2007-2013)/ERC grant agreement no. 268504 to KJG, and by NERC (grant no. NE/K005650/1) to FJFvV