Effects of oviposition by periodical cicadas on tree growth

2009 ◽  
Vol 39 (9) ◽  
pp. 1688-1697 ◽  
Author(s):  
Keith Clay ◽  
Angela L. Shelton ◽  
Chuck Winkle
Keyword(s):  
Tree Growth ◽  
Tree Species ◽  
Large Scale ◽  
Field Studies ◽  
Detectable Effect ◽  
Periodical Cicadas ◽  
Annual Growth Rings ◽  
Large Scale Field ◽  
Successional Forests ◽  
Long Term Impact

Periodical cicadas ( Magicicada spp.) occur at very high densities and synchronously emerge from underground every 13 or 17 years. During the emergence, adults lay eggs in tree branches, causing significant damage; however, the long-term impact of this damage is unknown. We conducted two large-scale field studies during the 2004 emergence of one brood (Brood X) to measure the growth of trees in relation to oviposition damage by periodical cicadas. In the first experiment, we netted areas to exclude cicadas from plots in 15 early successional forests and then measured trunk circumference for 3 years on more than 4000 trees of 52 species. In this experiment, oviposition had no detectable effect on the growth rates of trees. In the second study, we measured oviposition on 12 common tree species across six sites. We then measured the annual growth rings of these trees for 3 years after the emergence. In this experiment, oviposition was correlated with a slightly reduced growth in the emergence year and following year when the data were analyzed together, but when tree species were examined individually there were no clear effects of oviposition on tree growth. These data suggest cicada oviposition has little effect on the radial growth of trees, particularly in comparison to other factors.

scholarly journals Occupational exoskeletons: A roadmap toward large-scale adoption. Methodology and challenges of bringing exoskeletons to workplaces

2021 ◽  
Vol 2 ◽  
Author(s):  
Simona Crea ◽  
Philipp Beckerle ◽  
Michiel De Looze ◽  
Kevin De Pauw ◽  
Lorenzo Grazi ◽  
...  
Keyword(s):  
Large Scale ◽  
Health And Safety ◽  
Field Studies ◽  
Specific Work ◽  
Safety Standards ◽  
Knowledge Based ◽  
Scientific Papers ◽  
Large Scale Field ◽  
Standards And Regulations ◽  
Definition Of

Abstract The large-scale adoption of occupational exoskeletons (OEs) will only happen if clear evidence of effectiveness of the devices is available. Performing product-specific field validation studies would allow the stakeholders and decision-makers (e.g., employers, ergonomists, health, and safety departments) to assess OEs’ effectiveness in their specific work contexts and with experienced workers, who could further provide useful insights on practical issues related to exoskeleton daily use. This paper reviews present-day scientific methods for assessing the effectiveness of OEs in laboratory and field studies, and presents the vision of the authors on a roadmap that could lead to large-scale adoption of this technology. The analysis of the state-of-the-art shows methodological differences between laboratory and field studies. While the former are more extensively reported in scientific papers, they exhibit limited generalizability of the findings to real-world scenarios. On the contrary, field studies are limited in sample sizes and frequently focused only on subjective metrics. We propose a roadmap to promote large-scale knowledge-based adoption of OEs. It details that the analysis of the costs and benefits of this technology should be communicated to all stakeholders to facilitate informed decision making, so that each stakeholder can develop their specific role regarding this innovation. Large-scale field studies can help identify and monitor the possible side-effects related to exoskeleton use in real work situations, as well as provide a comprehensive scientific knowledge base to support the revision of ergonomics risk-assessment methods, safety standards and regulations, and the definition of guidelines and practices for the selection and use of OEs.

scholarly journals Tree growth is more limited by drought in rear-edge forests most of the times

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
J. Julio Camarero ◽  
Antonio Gazol ◽  
Gabriel Sangüesa-Barreda ◽  
Marta Vergarechea ◽  
Raquel Alfaro-Sánchez ◽  
...  
Keyword(s):  
Tree Growth ◽  
Tree Species ◽  
Large Scale ◽  
Abies Alba ◽  
Growth Patterns ◽  
Widespread Species ◽  
Growth Variability ◽  
Rear Edge ◽  
Species Vulnerability ◽  
The Impact

Abstract Background Equatorward, rear-edge tree populations are natural monitors to estimate species vulnerability to climate change. According to biogeographical theory, exposition to drought events increases with increasing aridity towards the equator and the growth of southern tree populations will be more vulnerable to drought than in central populations. However, the ecological and biogeographical margins can mismatch due to the impact of ecological factors (topography, soils) or tree-species acclimation that can blur large-scale geographical imprints in trees responses to drought making northern populations more drought limited. Methods We tested these ideas in six tree species, three angiosperms (Fagus sylvatica, Quercus robur, Quercus petraea) and three gymnosperms (Abies alba, Pinus sylvestris and Pinus uncinata) by comparing rear-edge tree populations subjected to different degrees of aridity. We used dendrochronology to compare the radial-growth patterns of these species in northern, intermediate, and southern tree populations at the continental rear edge. Results and conclusions We found marked variations in growth variability between species with coherent patterns of stronger drought signals in the tree-ring series of the southern populations of F. sylvatica, P. sylvestris, and A. alba. This was also observed in species from cool-wet sites (P. uncinata and Q. robur), despite their limited responsiveness to drought. However, in the case of Q. petraea the intermediate population showed the strongest relationship to drought. For drought-sensitive species as F. sylvatica and P. sylvestris, southern populations presented more variable growth which was enhanced by cool-wet conditions from late spring to summer. We found a trend of enhanced vulnerability to drought in these two species. The response of tree growth to drought has a marked biogeographical component characterized by increased drought sensitivity in southern populations even within the species distribution rear edge. Nevertheless, the relationship between tree growth and drought varied between species suggesting that biogeographical and ecological limits do not always overlap as in the case of Q. petraea. In widespread species showing enhanced vulnerability to drought, as F. sylvatica and P. sylvestris, increased vulnerability to climate warming in their rear edges is forecasted. Therefore, we encourage the monitoring and conservation of such marginal tree populations.

Do Intentions Really Predict Behavior? Self-Generated Validity Effects in Survey Research

2005 ◽  
Vol 69 (2) ◽  
pp. 1-14 ◽  
Author(s):  
Pierre Chandon ◽  
Vicki G. Morwitz ◽  
Werner J. Reinartz
Keyword(s):  
Large Scale ◽  
Field Studies ◽  
Purchase Intentions ◽  
Purchase Behavior ◽  
Second Stage ◽  
Large Scale Field ◽  
Reactive Effect ◽  
And Behavior ◽  
The Relationship ◽  
Measurement Effects

Studies of the relationship between purchase intentions and purchase behavior have ignored the possibility that the very act of measurement may inflate the association between intentions and behavior, a phenomenon called “self-generated validity.” In this research, the authors develop a latent model of the reactive effects of measurement that is applicable to intentions, attitude, or satisfaction data, and they show that this model can be estimated with a two-stage procedure. In the first stage, the authors use data from surveyed consumers to predict the presurvey latent purchase intentions of both surveyed and nonsurveyed consumers. In the second stage, they compare the strength of the association between the presurvey latent intentions and the postsurvey behavior across both groups. The authors find large and reliable self-generated validity effects across three diverse large-scale field studies. On average, the correlation between latent intentions and purchase behavior is 58% greater among surveyed consumers than it is among similar nonsurveyed consumers. One study also shows that the reactive effect of the measurement of purchase intentions is entirely mediated by self-generated validity and not by social norms, intention modification, or other measurement effects that are independent of presurvey latent intentions.

Assessing Insecticide Effects in Forests: A Tree-Level Approach Using Unmanned Aerial Vehicles

2019 ◽  
Vol 112 (6) ◽  
pp. 2686-2694
Author(s):  
Benjamin M L Leroy ◽  
Martin M Gossner ◽  
Florian P M Lauer ◽  
Ralf Petercord ◽  
Sebastian Seibold ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Large Scale ◽  
Feeding Activity ◽  
Field Studies ◽  
Tree Level ◽  
Biological Traits ◽  
Thaumetopoea Processionea ◽  
Aerial Vehicles ◽  
Large Scale Field ◽  
Individual Trees

Abstract Large-scale field studies on the ecological effects of aerial forest spraying often face methodological challenges, such as insufficient funding, difficult logistics, and legal obstacles. The resulting routine use of underpowered designs could lead to a systematic underestimation of insecticide effects on nontarget arthropod communities. We tested the use of an Unmanned Aerial Vehicles (UAVs) for experimental insecticide applications at tree level to increase replication in cost-efficient way. We assessed the effects of two forestry insecticides, diflubenzuron (DFB) and tebufenozide (TBF), on the oak defoliator, Thaumetopoea processionea (Linnaeus) (Lepidoptera: Thaumetopoeidae), and on nontarget, tree-living Lepidoptera. Individual trees were sprayed with either insecticide or left unsprayed, in a fully factorial design involving 60 trees. Caterpillars fallen from tree crowns were sampled as a measure of mortality, while caterpillar feeding activity was monitored by collecting frass droppings. Both DFB and TBF led to greater mortality of T. processionea and lower Lepidoptera feeding activity than control levels. TBF caused measurable mortality in nontarget groups, affecting Macrolepidoptera more strongly than Microlepidoptera, while there was no significant side effect of DFB. The high treatment efficacy against the target pest indicates that UAV technology is well-suited for the application of insecticide in forests. We detected distinct responses to different insecticides among nontarget groups and suggest there is an influence of application timing and biological traits in these differences, emphasizing the need for more ecologically orientated risk assessment. UAV-supported designs can be used to link laboratory bioassays and large-scale experiments, allowing for more comprehensive assessments of insecticide effects in forest ecosystems.

Research on Mobile HCI

2014 ◽  
pp. 76-93 ◽  
Author(s):  
Robert Schleicher ◽  
Tilo Westermann ◽  
Benjamin Weiss ◽  
Ina Wechsung ◽  
Sebastian Möller
Keyword(s):  
General Framework ◽  
Large Scale ◽  
Field Studies ◽  
Context Dependency ◽  
World Cup ◽  
Future Directions ◽  
The Third ◽  
Large Scale Field ◽  
Usage Situation

This chapter addresses the issue of context-dependency in research on mobile human computer interaction (HCI) with an emphasis on large-scale field studies. Based on a general framework that includes all the factors relevant for Quality of Experience (QoE), the authors first show how context affects basic processes on the side of the user as well the system or device. Then the authors describe three own studies where they aimed to account for context in app usage. The first tried to do so by offering an app for a very specific usage situation (commenting soccer world cup games), the second groups related applications of one domain (on-campus service for students) in an app-in-app bundle. The third example illustrates how evaluation of one single app across various contexts can be achieved in a classic field trial. Based on the authors’ experiences, they provide recommendations what to consider when planning a study and finally point out future directions of research.

Development of a Large-Scale Field System for Screening Peanut for Resistance to Preharvest Aflatoxin Contamination1

1994 ◽  
Vol 21 (1) ◽  
pp. 20-22 ◽  
Author(s):  
C. Corley Holbrook ◽  
Michael E. Matheron ◽  
David M. Wilson ◽  
William F. Anderson ◽  
M. Elizabeth Will ◽  
...  
Keyword(s):  
Large Scale ◽  
Irrigation System ◽  
Extended Period ◽  
Field Studies ◽  
Aflatoxin Contamination ◽  
Sources Of Resistance ◽  
Field System ◽  
Scale Field ◽  
Large Scale Field ◽  
A Site

Abstract Preharvest aflatoxin contamination (PAC) of peanut occurs under prolonged periods of drought and heat stress. Evaluation of peanut germplasm may identify valuable sources of resistance to PAC, but will require a large scale screening system. The objective of this research was to develop a large-scale field system for screening peanut germplasm for resistance to PAC at Yuma, Arizona. Yuma is located in a desert and has great potential as a site for evaluating germplasm for resistance to PAC. Field studies were conducted in 1990 to determine if aflatoxin contamination would occur in drought stressed peanuts grown at Yuma. Aflatoxin levels up to 2,260 ppb were observed, however, 52% of the plots escaped contamination and the coefficient of variation (C.V.) were unacceptably large. During testing at Yuma in 1990 it was noted that drought stressed plants died quickly due to the rapid exhaustion of soil moisture. A subsurface irrigation system was installed in 1991 to alleviate this problem and allow for an extended period of drought stress in the pod zone. Results for 1991 showed a greatly increased mean aflatoxin contamination, a 50% reduction in the C.V., and a virtual elimination in the occurrence of escapes. A study was conducted in 1992 to compare plots with and without subsurface irrigation to determine if the differences observed between 1990 and 1991 were due to the use of subsurface irrigation. The use of subsurface irrigation in 1992 increased the mean contamination by over 100%, reduced the C.V. by over 50%, and reduced the percentage of escapes by over 90%.

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