Bird predation affects canopy-living arthropods in city parks

1999 ◽  
Vol 77 (9) ◽  
pp. 1419-1428 ◽  
Author(s):  
Bengt Gunnarsson ◽  
Mikael Hake
Keyword(s):  
Betula Pendula ◽  
Experimental Treatment ◽  
Size Distributions ◽  
Bird Predation ◽  
Predator Prey ◽  
City Parks ◽  
General Importance ◽  
Arboreal Arthropods ◽  
The Impact ◽  
Average Body

Earlier studies suggest a significant top-down impact of vertebrate predators on arboreal arthropods. However, the general importance of such predator-prey interactions is not yet established. The impact of bird predation on macro-arthropods living in canopies of birch (Betula pendula) and oak (Quercus robur) was studied at six sites in four city parks in Göteborg, southwestern Sweden. In a 17-week field experiment we manipulated the bird-predation pressure on arthropods on birch and oak branches. Passerine numbers differed significantly between birch sites but not between oak sites. Bird predation significantly reduced the abundance on both birch and oak branches of seven out of nine arthropod taxa examined: Araneae, Opiliones, Dermaptera, Psocoptera, Heteroptera (oak only), Coleoptera, and Lepidoptera (birch only). For birch, arthropods were of larger average body size on experimental than on control branches at two sites. At the third site, however, arthropods were larger on control branches. For oak, arthropods were significantly larger on experimental than on control branches at two sites. At the remaining site, in the same park as the deviating birch site, there was no difference between size distributions. Thus, in one of the parks, experimental effects on size distributions at birch and oak sites contradicted the results from the other parks. Site effects on arthropod abundance were found for three insect taxa on birch and one insect taxon on oak. There were significant interactions between experimental treatment and site for Dermaptera on birch and for Araneae on oak. Although one of the parks (the central one) differed from the others in certain aspects, the results suggest that overall, bird predation was not seriously affected by the urban environment. We conclude that bird predation on arthropods is an important link in canopy food webs of temperate-zone forests.

scholarly journals Size-resolved characterization of organic aerosol in the North China Plain: new insights from high resolution spectral analysis

2021 ◽  
Author(s):  
Weiqi Xu ◽  
Chun Chen ◽  
Yanmei Qiu ◽  
Conghui Xie ◽  
Yunle Chen ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Fine Particles ◽  
Large Fraction ◽  
Organic Aerosol ◽  
Size Distributions ◽  
The North ◽  
The Impact

Organic aerosol (OA), a large fraction of fine particles, has a large impact on climate radiative forcing and human health, and the impact depends strongly on size distributions. Here we...

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

scholarly journals The impact of large terrestrial carnivores on Pleistocene ecosystems

2015 ◽  
Vol 113 (4) ◽  
pp. 862-867 ◽  
Author(s):  
Blaire Van Valkenburgh ◽  
Matthew W. Hayward ◽  
William J. Ripple ◽  
Carlo Meloro ◽  
V. Louise Roth
Keyword(s):  
Prey Size ◽  
Habitat Degradation ◽  
Terrestrial Ecosystems ◽  
Growth Data ◽  
Predator Prey ◽  
Body Sizes ◽  
Population Sizes ◽  
Potential Impact ◽  
The Impact ◽  
Ground Sloths

Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator–prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.

scholarly journals Impact of pathogen reduction methods on immunological properties of the COVID-19 convalescent plasma

2020 ◽  
Author(s):  
Alexander I. Kostin ◽  
Maria N. Lundgren ◽  
Andrey Y. Bulanov ◽  
Elena A. Ladygina ◽  
Karina S. Chirkova ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Neutralizing Antibodies ◽  
Paired Comparison ◽  
Experimental Treatment ◽  
Specific Antibodies ◽  
Immunological Properties ◽  
Reduction Methods ◽  
One Step ◽  
Pathogen Reduction ◽  
The Impact

ABSTRACTBackground and ObjectivesCOVID-19 convalescent plasma is an experimental treatment against SARS-CoV-2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS-CoV2 in convalescent plasma.Materials and MethodsA total of 140 plasma doses collected by plasmapheresis from COVID-19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB, and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS-CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S- and N- proteins of SARS-CoV-2 were measured before and after pathogen reduction.ResultsThe methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7% respectively) had a one- step (two-step respectively) decrease. Paired two-sample comparisons (M vs A, M vs R and A vs R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment.ConclusionPathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID-19 convalescent plasma compared to riboflavin.

scholarly journals Insectivorous bats are less active near freeways

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247400
Author(s):  
Manisha Bhardwaj ◽  
Kylie Soanes ◽  
José J. Lahoz-Monfort ◽  
Linda F. Lumsden ◽  
Rodney van der Ree
Keyword(s):  
Agricultural Landscapes ◽  
Individual Species ◽  
Insectivorous Bats ◽  
Predator Prey ◽  
The Road ◽  
Environmental Impact Assessments ◽  
Wildlife Populations ◽  
Roadside Verges ◽  
The Impact ◽  
Plant Pollinator

Traffic disturbances (i.e. pollution, light, noise, and vibrations) often extend into the area surrounding a road creating a ‘road-effect zone’. Habitat within the road-effect zone is degraded or, in severe cases, completely unsuitable for wildlife, resulting in indirect habitat loss. This can have a disproportionate impact on wildlife in highly modified landscapes, where remaining habitat is scarce or occurs predominantly along roadside reserves. In this study, we investigated the road-effect zone for insectivorous bats in highly cleared agricultural landscapes by quantifying the change in call activity with proximity to three major freeways. The activity of seven out of 10 species of bat significantly decreased with proximity to the freeway. We defined the road-effect zone to be the proximity at which call activity declined by at least 20% relative to the maximum detected activity. The overall road-effect zone for bats in this region was 307 m, varying between 123 and 890 m for individual species. Given that this road-effect zone exceeds the typical width of the roadside verges (<50 m), it is possible that much of the vegetation adjacent to freeways in this and similar landscapes provides low-quality habitat for bats. Without accounting for the road-effect zone, the amount of habitat lost or degraded due to roads is underestimated, potentially resulting in the loss of wildlife, ecosystem services and key ecosystem processes (e.g. predator-prey or plant-pollinator interactions) from the landscape. We suggest all future environmental impact assessments include quantifying the road-effect zone for sensitive wildlife, in order to best plan and mitigate the impact of roads on the environment. Mitigating the effects of new and existing roads on wildlife is essential to ensure enough high-quality habitat persists to maintain wildlife populations.

scholarly journals Dysregulated interactions triggered by a neuropathy-causing mutation in the IPV motif of HSP27

2019 ◽  
Author(s):  
T. Reid Alderson ◽  
Elias Adriaenssens ◽  
Bob Asselbergh ◽  
Iva Pritišanac ◽  
Heidi Y. Gastall ◽  
...  
Keyword(s):  
Small Heat Shock Protein ◽  
Severe Form ◽  
Protein Protein Interaction ◽  
Charcot Marie Tooth Disease ◽  
System A ◽  
General Importance ◽  
Mechanistic Basis ◽  
The Impact

HSP27 (HSPB1) is a systemically expressed human small heat-shock protein that forms large, dynamic oligomers and functions in various aspects of cellular homeostasis. Mutations in HSP27 cause Charcot-Marie-Tooth disease, the most common inherited disorder of the peripheral nervous system. A particularly severe form of the disease is triggered by the P182L mutation within the highly conserved IxI/V motif of HSP27. Here, we observed that the P182L variant of HSP27 lacks the ability to prevent the aggregation of client proteins and formed significantly larger oligomers both in vitro and in vivo. NMR spectroscopy revealed that the P182L IxI/V motif binds its α-crystallin domain with significantly lower association rate, and thus affinity, rendering the binding site more available for other interactors. We identified 22 IxI/V-containing proteins that are known to interact with HSP27 and could therefore bind with enhanced affinity to the P182L variant. We validated this hypothesis through co-immunoprecipitation experiments, revealing that the IxI/V motif-bearing co-chaperone BAG3 indeed binds with higher affinity to the P182L variant. Our results provide a mechanistic basis for the impact of the P182L mutation on HSP27, and highlight the general importance of the IxI/V motif and its role in protein-protein interaction networks.

scholarly journals Impact of diet deprivation and subsequent overallowance during gestation on lactation performance of primiparous sows1

2018 ◽  
Vol 2 (2) ◽  
pp. 162-168 ◽  
Author(s):  
Chantal Farmer ◽  
Kevin Herkelman ◽  
Brad James ◽  
Pierre Lessard ◽  
Arnaud Samson ◽  
...  
Keyword(s):  
Feed Intake ◽  
Experimental Treatment ◽  
Milk Composition ◽  
Late Gestation ◽  
Metabolic Status ◽  
Standard Diet ◽  
Lactation Performance ◽  
Dietary Regimen ◽  
Beneficial Effects ◽  
The Impact

Abstract The impact of diet deprivation followed by overallowance during gestation on metabolic status of pregnant gilts and their lactation performance was determined. Gilts were fed a standard diet until day 27 of gestation and were subsequently reared under a control (CTL; n = 28) or an experimental (treatment, TRT; n = 26) dietary regimen. The experimental regimen provided 70% (restriction diet, RES) and 115% (overallowance diet, OVER) of the protein and NE contents provided by the CTL diet. The RES diet was given from days 28 to 74 of gestation followed by the OVER diet from day 75 until farrowing. Blood samples were obtained from all gilts on days 28, 75, and 110 of gestation, and on days 3 and 20 of lactation to measure concentrations of IGF-1, urea, FFA, and glucose. Milk samples were collected from 12 sows per treatment on day 19 of lactation and sow feed intake was recorded daily throughout lactation. Piglets were weighed at 24 h (after standardization of litter size), and on days 7, 14, and 21 (weaning). The TRT gilts gained less BW than CTL gilts (17.3 vs. 31.7 kg; P &lt; 0.01) from days 28 to 75 of gestation and more BW (29.5 vs. 21.9 kg; P &lt; 0.01) from days 75 to 110, but their overall gain from mating to day 110 was lower (61.4 vs. 67.2 kg; P &lt; 0.05). Metabolic status during gestation was affected, with TRT gilts having less IGF-1 and urea, and more FFA than CTL gilts on day 75 (P &lt; 0.01), and more urea on day 110 (P &lt; 0.01). Growth rate of suckling piglets, sow lactation feed intake, and standard milk composition in late lactation (DM, fat, protein, lactose) were not affected by treatment (P &gt; 0.10). In conclusion, diet deprivation of gilts as of day 28 of gestation followed by overfeeding from day 75 of gestation until farrowing did not improve lactation performance. It is likely that the compensatory growth that took place in late gestation was not adequate to illicit beneficial effects.

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