The Effect of Urbanization on Bumble Bee Communities in Greater Philadelphia

Bumble bees (Bombus spp.) are among the most important wild pollinators in temperate ecosystems in North America and Europe, and are believed to be vital to the functioning of the pollination networks in which they occur. Accordingly, evidence of their overall decline in Europe and more selective decline in the U.S. has raised concern about the long term persistence of many species. Human-induced changes in land use, including the loss of natural and semi-natural habitat and associated floral resources, are purported causes in several cases. Declines prompted an investigation of this potential trend in the urbanized landscape in and surrounding Philadelphia, PA. We surveyed the species richness and abundance of bumble bee communities in ten half-ha plots located in restored, managed meadows along a gradient of urban and suburban development in the Philadelphia metropolitan area from June 1 to August 15, 2006. In conjunction with collections, we measured floral density within each plot. We calculated the proportion of developed land at differing spatial scales ranging from 500 to 4000 m from survey sites. General linear models were used to test the effect of developed land, local meadow size, and floral resource density on overall bumble bee species richness and abundance. 
Development did not have any detectable effect on species richness at any tested spatial scale. Bee abundance was best explained by a model that included the proportion of developed land at the 2500 m scale. In contrast to our expectations, total bumble bee abundance was significantly higher in plots with a higher proportion of developed land surrounding the site (F1,5 = 8.13, P = 0.04). Local floral density did not significantly affect richness or abundance (F 1,5 = 0.93, P = 0.34), nor was local resource quality associated with development (r = 0.52, P = 0.12) . We hypothesize that gardens maintained in urban and suburban landscapes may provide an important and consistent food supply to bumble bees throughout the duration of their colony cycle. Forested habitats, which were the other dominate habitat type, may actually be relatively poor in bumble bee resources following closure of the canopy in late spring. This research indicates that restored meadows are excellent habitat for bumble bees and may promote pollination services in urbanized settings.
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The impact of conifer harvesting on stream water quality: the Afon Hafren, mid-Wales

International audienceResults for long term water quality monitoring are described for the headwaters of the principal headwater stream of the River Severn, the Afon Hafren. The results are linked to within-catchment information to describe the influence of conifer harvesting on stream and shallow groundwater quality. A 19-year record of water quality data for the Hafren (a partially spruce forested catchment with podzolic soil) shows the classic patterns of hydrochemical change in relation to concentration and flow responses for upland forested systems. Progressive felling of almost two-thirds of the forest over the period of study resulted in little impact from harvesting and replanting in relation to stream water quality. However, at the local scale, a six years' study of felling indicated significant release of nitrate into both surface and groundwater; this persisted for two or three years before declining. The study has shown two important features. Firstly, phased felling has led to minimal impacts on stream water. This contrasts with the results of an experimental clear fell for the adjacent catchment of the Afon Hore where a distinct water quality deterioration was observed for a few years. Secondly, there are localised zones with varying hydrology that link to groundwater sources with fracture flow properties. This variability makes extrapolation to the catchment scale difficult without very extensive monitoring. The implications of these findings are discussed in relation to strong support for the use of phased felling-based management of catchments and the complexities of within catchment processes. Keywords: deforestation, water quality, acidification, pH, nitrate, alkalinity, ANC, aluminium, dissolved organic carbon, Plynlimon, forest, spruce, Afon Hafren, podzo

The water quality of streams draining a plantation forest on gley soils: the Nant Tanllwyth, Plynlimon mid-Wales

International audienceThe water quality of the Nant Tanllwyth stream in the Plynlimon region of mid-Wales is related to the key hydrobiogeological controls and the effects of conifer harvesting based on an analysis of rain, cloud, stream and groundwater measurements. The results show the normal patterns of stream water quality response to hydrology. Thus, there is a high damping of atmospheric inputs due to storage in a highly heterogeneous soil and groundwater system. Correspondingly, there is a highly dynamic response for components such as calcium, bicarbonate and aluminium. This response links to the relative inputs of acidic and aluminium-bearing soil waters under high flow conditions and base enriched bicarbonate bearing waters from the groundwater areas under baseflow conditions. The introduction of a deep borehole near the main stem of the river opened up a groundwater flow route to the stream and other parts of the catchment. There were two aspects to this. Firstly, it caused a change to the stream water quality, particularly under baseflow conditions, by increasing the concentrations of calcium and magnesium and by reducing the acidity. The monitoring shows that this change has persisted for over eight years and that there is no sign of reversion to pre-borehole times. Secondly, it caused a change in the groundwater level and chemistry at a borehole on the other side of the river. This feature shows that the fracture system is of hydrogeochemical and hydrogeological complexity. The effects of conifer harvesting are remarkable. At the local scale, felling leads to the expected short term increase in nitrate, ammonium and phosphate from the disturbance of the soil and the reduction in uptake into the vegetation. Correspondingly, there is a reduction in sodium and chloride linked to reduced scavenging of atmospheric inputs from cloud water by the vegetation and also due to increased dilution potential due to reductions in transpiration by the trees. However, within the main stream, virtually no change is observed in stream water quality with felling, except for a decrease rather than an expected increase in nitrate concentration. It seems that the increase in phosphate, for a system that is essentially phosphate limiting, has stimulated biological activity in the stream leading to increased uptake of nitrate and ammonium. However, there is little change in the sodium and chloride in the stream and there are important issues of the representative nature of studying small scale drainage areas. Boreholes, introduced to assess the impacts of the felling programme, show unexpected variations in groundwater chemistry. These variations are associated with the complexity of both flow routing and the chemical reactivity within the groundwater and lower soil zones, rather than changes that can be linked specifically to felling. The implications of the study are discussed in relation to both process understanding and forestry management practices. Keywords: water quality, acidification, conifer, harvesting, pH, nitrate, ammonium, phosphate, nutrients, alkalinity, Plynlimon, Wales, Tanllwyth, streams, groundwate

Wildflower plantings have mixed effects on insect herbivores and their natural enemies

Flower strips are advocated as a strategy to promote beneficial insects as well as the services they deliver to adjacent crops. Flower strips have, however, often been developed separately for pollinators and natural enemies and, additionally, little consideration has been given to effects on insect herbivores. We sampled insect herbi-vores, their natural enemies and parasitism of pest eggs using vacuum sampling, sticky cards and egg cards in nine pairs of bee-attractive wildflower plantings and control field borders, as well as in adjacent tomato and watermelon crop fields in Yolo County, California 2015-2016. Control field borders had a higher total number of herbivores on sticky traps than did wildflower plantings, a pattern that was driven by more aphids, hoppers, psyllids and whiteflies, whereas wildflower plantings had more lace bugs and Lygus bugs. The total number of herbivores in the adjacent crop fields did not differ between treatments, but there were more leaf beetles near (at 10 m but not 50 m from) wildflower plantings. Control field borders had a higher total number of predators, driven by more big-eyed bugs, lady beetles and minute pirate bugs, whereas spiders were more common in wildflower plantings. The total number of predators in adjacent crop fields was, however, higher in those next to wildflower plantings, which was driven by more minute pirate bugs. Parasitoid wasps were more common in wildflower plantings and at 10 m but not 50 m into adjacent crop fields. Stink bug egg parasitism rate did not differ between treatments, either in the borders or in the crop fields. In conclusion, wildflower plantings clearly affect the insect herbivore and natural enemy community, but do so in a highly taxon-specific manner, which can lead to both positive and negative outcomes for pest control as a result

Statistical Mechanics of Learning: A Variational Approach for Real Data

Using a variational technique, we generalize the statistical physics approach of learning from random examples to make it applicable to real data. We demonstrate the validity and relevance of our method by computing approximate estimators for generalization errors that are based on training data alone.Comment: 4 pages, 2 figure

Nature Of Transition Circumstellar Disks. I. The Ophiuchus Molecular Cloud

We have obtained millimeter-wavelength photometry, high-resolution optical spectroscopy, and adaptive optics near-infrared imaging for a sample of 26 Spitzer-selected transition circumstellar disks. All of our targets are located in the Ophiuchus molecular cloud (d similar to 125 pc) and have spectral energy distributions (SEDs) suggesting the presence of inner opacity holes. We use these ground-based data to estimate the disk mass, multiplicity, and accretion rate for each object in our sample in order to investigate the mechanisms potentially responsible for their inner holes. We find that transition disks are a heterogeneous group of objects, with disk masses ranging from <0.6 to 40 M(JUP) and accretion rates ranging from <10(-11) to 10(-7) M(circle dot) yr(-1), but most tend to have much lower masses and accretion rates than "full disks" (i.e., disks without opacity holes). Eight of our targets have stellar companions: six of them are binaries and the other two are triple systems. In four cases, the stellar companions are close enough to suspect they are responsible for the inferred inner holes. We find that nine of our 26 targets have low disk mass (<2.5 M(JUP)) and negligible accretion (<10(-11) M(circle dot) yr(-1)), and are thus consistent with photoevaporating (or photoevaporated) disks. Four of these nine non-accreting objects have fractional disk luminosities <10(-3) and could already be in a debris disk stage. Seventeen of our transition disks are accreting. Thirteen of these accreting objects are consistent with grain growth. The remaining four accreting objects have SEDs suggesting the presence of sharp inner holes, and thus are excellent candidates for harboring giant planets.NASA 1224608, 1230782, 1230779, 1407FONDECYT 1061199Basal CATA PFB 06/09ALMA FUND 31070021ALMA-Conicyt FUND 31060010National Science Foundation AST0-808144Spitzer Space Telescope Legacy Science ProgramAstronom

A Real-Time Brain-Machine Interface Combining Motor Target and Trajectory Intent Using an Optimal Feedback Control Design

Real-time brain-machine interfaces (BMI) have focused on either estimating the continuous movement trajectory or target intent. However, natural movement often incorporates both. Additionally, BMIs can be modeled as a feedback control system in which the subject modulates the neural activity to move the prosthetic device towards a desired target while receiving real-time sensory feedback of the state of the movement. We develop a novel real-time BMI using an optimal feedback control design that jointly estimates the movement target and trajectory of monkeys in two stages. First, the target is decoded from neural spiking activity before movement initiation. Second, the trajectory is decoded by combining the decoded target with the peri-movement spiking activity using an optimal feedback control design. This design exploits a recursive Bayesian decoder that uses an optimal feedback control model of the sensorimotor system to take into account the intended target location and the sensory feedback in its trajectory estimation from spiking activity. The real-time BMI processes the spiking activity directly using point process modeling. We implement the BMI in experiments consisting of an instructed-delay center-out task in which monkeys are presented with a target location on the screen during a delay period and then have to move a cursor to it without touching the incorrect targets. We show that the two-stage BMI performs more accurately than either stage alone. Correct target prediction can compensate for inaccurate trajectory estimation and vice versa. The optimal feedback control design also results in trajectories that are smoother and have lower estimation error. The two-stage decoder also performs better than linear regression approaches in offline cross-validation analyses. Our results demonstrate the advantage of a BMI design that jointly estimates the target and trajectory of movement and more closely mimics the sensorimotor control system.National Institutes of Health (U.S.) (NIH grant No.DP1-0D003646-01)National Institutes of Health (U.S.) (NIH grant R01-EB006385

Species Abundance, Not Diet Breadth, Drives the Persistence of the Most Linked Pollinators as Plant-Pollinator Networks Disassemble

Theoretical and simulation studies predict that the order of species loss from mutualist networks with respect to how linked species are to other species within the network will determine the rate at which networks collapse. However, the empirical order of species loss with respect to linkage has rarely been investigated. Furthermore, a species' linkage is a composite of its diet breadth and its abundance, yet the relative importance of these two factors in determining species loss order is poorly known. Here we explore the order of pollinator species loss in two contrasting study systems undergoing land-use intensification, using &gt;20,000 pollinator specimens. We found that a pollinator species' linkage, as measured independently within plant-pollinator networks, positively predicted its persistence at human-disturbed sites in three of four analyses. The strongest predictor of persistence in all analyses was pollinator species abundance. In contrast, diet breadth poorly predicted persistence. Overall, our results suggest that community disassembly order buffers plant-pollinator networks against environmental change by retaining the highly linked species that make a disproportionate contribution to network robustness. Furthermore, these highly linked species likely persist because they are also the most common species, not because they are dietary generalists

Patient-reported measurement of time to diagnosis in cancer: development of the Cancer Symptom Interval Measure (C-SIM) and randomised controlled trial of method of delivery

Background: The duration between first symptom and a cancer diagnosis is important because, if shortened, may lead to earlier stage diagnosis and improved cancer outcomes. We have previously developed a tool to measure this duration in newly-diagnosed patients. In this two-phase study, we aimed further improve our tool and to conduct a trial comparing levels of anxiety between two modes of delivery: self-completed versus researcher-administered. Methods: In phase 1, ten patients completed the modified tool and participated in cognitive debrief interviews. In phase 2, we undertook a Randomised Controlled Trial (RCT) of the revised tool (Cancer Symptom Interval Measure (C-SIM)) in three hospitals for 11 different cancers. Respondents were invited to provide either exact or estimated dates of first noticing symptoms and presenting them to primary care. The primary outcome was anxiety related to delivery mode, with completeness of recording as a secondary outcome. Dates from a subset of patients were compared with GP records. Results: After analysis of phase 1 interviews, the wording and format were improved. In phase 2, 201 patients were randomised (93 self-complete and 108 researcher-complete). Anxiety scores were significantly lower in the researcher-completed group, with a mean rank of 83.5; compared with the self-completed group, with a mean rank of 104.0 (Mann-Whitney U = 3152, p = 0.007). Completeness of data was significantly better in the researcher-completed group, with no statistically significant difference in time taken to complete the tool between the two groups. When comparing the dates in the patient questionnaires with those in the GP records, there was evidence in the records of a consultation on the same date or within a proscribed time window for 32/37 (86%) consultations; for estimated dates there was evidence for 23/37 consultations (62%). Conclusions: We have developed and tested a tool for collecting patient-reported data relating to appraisal intervals, help-seeking intervals, and diagnostic intervals in the cancer diagnostic pathway for 11 separate cancers, and provided evidence of its acceptability, feasibility and validity. This is a useful tool to use in descriptive and epidemiological studies of cancer diagnostic journeys, and causes less anxiety if administered by a researcher