The shape of a defense-growth trade-off governs seasonal trait dynamics in natural phytoplankton

2018 ◽  
Author(s):  
Elias Ehrlich ◽  
Nadja J. Kath ◽  
Ursula Gaedke
Keyword(s):  
Fitness Landscape ◽  
Functional Trait ◽  
Grazing Pressure ◽  
Trait Variation ◽  
Trade Off ◽  
Community Persistence ◽  
Trade Offs ◽  
Combining Data ◽  
Persistence Theory

Functional trait compositions of communities can adapt to altered environmental conditions ensuring community persistence. Theory predicts that the shape of trade-offs between traits crucially affects these trait dynamics, but its empirical verification from the field is missing. Here, we show how the shape of a defense-growth trade-off governs seasonal trait dynamics of a natural community, using high-frequency, long-term measurements of phytoplankton from Lake Constance. As expected from the lab-derived concave trade-off curve, we observed an alternating dominance of several fast-growing species with intermediate defense levels and gradual changes of the biomass-trait distribution due to seasonally changing grazing pressure. By combining data and modelling, we obtain mechanistic insights on the underlying fitness landscape, and show that low fitness differences can maintain trait variation along the trade-off curve. We provide firm evidence for a frequently assumed trade-off and conclude that quantifying its shape allows to understand environmentally driven trait changes within communities.

scholarly journals Using Artificial Intelligence to classify Jobseekers: The Accuracy-Equity Trade-off

2020 ◽  
pp. 1-19
Author(s):  
SAM DESIERE ◽  
LUDO STRUYVEN
Keyword(s):  
Artificial Intelligence ◽  
Maximum Level ◽  
Employment Services ◽  
Trade Off ◽  
The Public ◽  
Foreign Origin ◽  
Trade Offs ◽  
Graphical Tool ◽  
The Cost

Abstract Artificial intelligence (AI) is increasingly popular in the public sector to improve the cost-efficiency of service delivery. One example is AI-based profiling models in public employment services (PES), which predict a jobseeker’s probability of finding work and are used to segment jobseekers in groups. Profiling models hold the potential to improve identification of jobseekers at-risk of becoming long-term unemployed, but also induce discrimination. Using a recently developed AI-based profiling model of the Flemish PES, we assess to what extent AI-based profiling ‘discriminates’ against jobseekers of foreign origin compared to traditional rule-based profiling approaches. At a maximum level of accuracy, jobseekers of foreign origin who ultimately find a job are 2.6 times more likely to be misclassified as ‘high-risk’ jobseekers. We argue that it is critical that policymakers and caseworkers understand the inherent trade-offs of profiling models, and consider the limitations when integrating these models in daily operations. We develop a graphical tool to visualize the accuracy-equity trade-off in order to facilitate policy discussions.

Do generalisations of global trade-offs in plant design apply to an Australian sclerophyllous flora?

2010 ◽  
Vol 58 (4) ◽  
pp. 257 ◽  
Author(s):  
Trevor L. Meers ◽  
Tina L. Bell ◽  
Neal J. Enright ◽  
Sabine Kasel
Keyword(s):  
Functional Groups ◽  
Arbuscular Mycorrhizal ◽  
Functional Trait ◽  
Global Scale ◽  
Plant Design ◽  
Annual Life Cycle ◽  
Trade Off ◽  
Global Trends ◽  
Ant Dispersal ◽  
Trade Offs

Functional-trait analysis at a global scale has found evidence for evolutionary specialisation of species into those designed to acquire resources rapidly and those designed to conserve resources. The present study aimed to determine whether such a trade-off exists in sclerophyllous vegetation in Australia. We measured 10 traits for 167 plant species. The first axis of a principal components analysis represented a trade-off between resource acquisition and resource conservation, consistent with global trends. Common traits shared by resource-conservative species included low specific leaf area (SLA), resprouting, ant-dispersal, and ericoid mycorrhizal and ectomycorrhizal associations. These attributes were typical of 3 of 13 functional groups produced by cluster analysis (eucalypts, ant-dispersed shrubs, ericoid heaths) that had the lowest SLA, and were almost exclusively native shrubs and trees. Resource-acquisitive species had high SLA, a small stature, annual life cycle, arbuscular mycorrhizal or non-mycorrhizal associations, and small, wind-dispersed seeds. These attributes are similar to those identified for species with a ruderal strategy and were typical of the functional groups representing wind-dispersed composites, AM annuals and non-mycorrhizal annuals that had the highest SLA and were dominated by introduced species. Comparable trait associations have been found in other studies, suggesting that similar processes drive plant design at a global scale. However, there were some patterns specific to the flora studied that were attributable to adaptations to suit the nutrient-poor soils and arid conditions typical of the Australian environment.

scholarly journals Injury alters motivational trade-offs in calves during the healing period

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah J. J. Adcock ◽  
Cassandra B. Tucker
Keyword(s):  
Startle Response ◽  
Risk Avoidance ◽  
Motivational State ◽  
Trade Off ◽  
Milk Bottle ◽  
Trade Offs ◽  
Long Term Changes ◽  
Motivational Changes ◽  
Time Since Injury

AbstractInjury can produce long-lasting motivational changes that may alter decisions made under risk. Our objective was to determine whether a routine painful husbandry procedure, hot-iron disbudding, affects how calves trade off risk avoidance against a competing motivation (i.e., feeding), and whether this response depends on time since injury. We used a startle test to evaluate this trade-off in calves disbudded 0 or 21 days previously and non-injured control calves. For 3 days, calves were individually habituated to the testing arena in which they received a 0.5 L milk meal via a rubber teat. On the 4thday, upon approaching the milk reward, the calf was startled by a sudden noise. We assessed the duration and magnitude of the calf’s startle response, their latency to return to the milk bottle, and duration spent suckling after startling. No treatment differences were observed in the duration and magnitude of the startle response or in the probability of returning to the bottle after startling. However, among those who did return, disbudded calves spent longer suckling, indicating they accepted more risk in order to feed compared to controls. In addition, calves with 21-day-old injuries tended to return to the bottle faster compared to newly disbudded calves and controls. We suggest that hot-iron disbudding increases calves’ motivation to suckle, as they were more likely to prioritize this behaviour over risk avoidance compared to control calves. This effect was most evident 21 days after disbudding, indicating that injury can produce long-term changes in motivational state.

scholarly journals Intraspecific root and leaf trait variation with tropical forest successional status: consequences for community-weighted patterns

2019 ◽  
Author(s):  
J. Aaron Hogan ◽  
Oscar J. Valverde-Barrantes ◽  
Qiong Ding ◽  
Han Xu ◽  
Christopher Baraloto
Keyword(s):  
Soil Fertility ◽  
Tropical Forest ◽  
Leaf Area ◽  
Specific Root Length ◽  
Functional Trait ◽  
Primary Forest ◽  
List Type ◽  
Forest Age ◽  
Trait Variation ◽  
Trade Offs

SummaryQuantifying the dimensions and magnitude of intraspecific root trait variation is key to understanding the functional trade-offs in the belowground plant strategies of tropical forest trees. Additionally, accurately measuring how belowground functional trait variation relates to soil environment and forest age is crucial to tropical forest modeling efforts.We sampled leaf and root morphologies from 423 juvenile trees of 72 species from 14 Angiosperm families along a 6.6 km transect that corresponded to an environmental gradient in decreasing soil fertility and texture with increasing forest age.We observed within-lineage conservative functional trait-shifts in root and leaf morphological traits along the transect. From secondary to primary forest, average leaf area increased 7 cm2and average root system diameter increased 0.4 mm. Mean specific leaf area decreased by 0.8 m2kg−1, specific root length decreased by 3.5 m kg−1, and root branching intensity decreased by 0.3 tips cm−1. Leaf thickness and root tissue density showed no change.We coupled trait measurements to a network of 164 1/16th-ha plots across a Chinese tropical forest reserve, to scale individual trait measurements up to the community-level, accounting for forest age.For most traits, intraspecific trait variation negatively covaried with species compositional turnover between plots in younger versus older forest to compound and create greater community-weighted differences in trait values than would be observed if intraspecific variation in traits with forest age was not accounted for.SummaryRoot morphologies are variable with local scale variation in soil fertility and texture. Accurately understanding broader (i.e. forest)-scale patterns in root functional traits, requires attention to underlying environmental variation in soil resources, which interacts with environmental filtering of plant communities.

Sex or survival: trade-offs between quality and quantity of life.

1991 ◽  
Vol 9 (2) ◽  
pp. 328-334 ◽  
Author(s):  
P A Singer ◽  
E S Tasch ◽  
C Stocking ◽  
S Rubin ◽  
M Siegler ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Clinical Practice ◽  
Survival Rate ◽  
The Other ◽  
Localized Prostate Cancer ◽  
Term Survival ◽  
Trade Off ◽  
Level Of Education ◽  
Trade Offs

Patients with localized prostate cancer may be treated with either surgery (radical prostatectomy) or radiotherapy. Although controversial, many physicians believe that surgery offers a higher survival rate. However, the surgical treatment may also produce a higher rate of sexual impotency. Our study assessed how men value survival and sexual potency when asked to trade off one for the other. Using the treatment-choice technique, we interviewed 50 men aged 45 to 70 years without known prostate cancer. At hypothetical rates of survival (90% at 5 years for surgery) and impotency (90% for surgery and 40% for radiotherapy) representing published estimates, 32% of respondents were unwilling to trade off any survival, but 68% were willing to trade off a 10% or greater advantage in 5-year survival (by choosing radiotherapy) to maintain sexual potency. The median 5-year survival traded off was 10% (range, 0% to 80%). Willingness to trade off survival for sexual potency was significantly related to level of education, but not to age, interest in sex, frequency of sexual intercourse, or ability to achieve erection. We conclude that some men may choose treatment with lower long-term survival to increase their chance of remaining sexually potent. Because these men may be difficult to identify in clinical practice, physicians should thoroughly discuss both surgery and radiotherapy options with patients who have localized prostate cancer.

scholarly journals Ensuring the Long-Term Provision of Heathland Ecosystem Services—The Importance of a Functional Perspective in Management Decision Frameworks

2021 ◽  
Vol 9 ◽  
Author(s):  
David C. Walmsley ◽  
Benjamin M. Delory ◽  
Isabel Alonso ◽  
Vicky M. Temperton ◽  
Werner Härdtle
Keyword(s):  
Ecosystem Services ◽  
Groundwater Recharge ◽  
Management Practices ◽  
Management Decision ◽  
Trade Off ◽  
Trade Offs ◽  
Heathland Management ◽  
Sod Cutting ◽  
Decision Frameworks

The ecosystem services framework can be used as a way of balancing economic, ecological and societal drivers in land management decision-making processes. As heathland management is typically linked directly to services, the aim of this study was to quantify trade-offs related to the effects of five common heathland management measures (grazing, mowing, burning, choppering, and sod-cutting) using quantitative data from empirical studies within a northwestern heathland in Germany. Besides important services (groundwater recharge and quality, carbon stocks and appreciation by the general public) we included ecosystem functions (balances of nitrogen, phosphorus and major cations) and the net cost of management implementation as trade-off components. We found that all management practices have advantages and disadvantages leading to unavoidable trade-offs. The effect of a management practice on the trade-off components was often closely related to the amount of biomass and/or soil removed during a management cycle (Rannual). Choppering and sod-cutting (large Rannual by involving soil removal) were very good at maintaining a low N system whilst concurrently increasing groundwater recharge, albeit at the cost of all other components considered. If the aim is to preserve heathlands and their associated ecosystem services in the long-term this trade-off is inevitable, as currently only these high-intensity measures are capable of removing enough nitrogen from the system to prevent the transition to non-heather dominated habitat types. Our study, therefore, shows that in order to maintain structural integrity and thereby the service potential a habitat provides, management decision frameworks may need to prioritize ecosystem functioning over ecosystem services. Burning and mowing (low Rannual) were best at retaining phosphorus, cations and carbon and had the lowest costs. Grazing (intermediate Rannual) provided the highest relative benefit in terms of groundwater quality and appreciation. Together these results can help identify management combinations in both space and time, which will be more beneficial for functions and services than management practices considered in isolation. Furthermore, our study assists in recognizing key areas of action for the development of novel management practices and can help raise awareness of the diversity of rare species and potential benefits to people that protected cultural landscapes provide.

Growth–defense trade-offs shape population genetic composition in an iconic forest tree species

2021 ◽  
Vol 118 (37) ◽  
pp. e2103162118 ◽  
Author(s):  
Olivia L. Cope ◽  
Ken Keefover-Ring ◽  
Eric L. Kruger ◽  
Richard L. Lindroth
Keyword(s):  
Evolutionary Dynamics ◽  
Evolutionary Ecology ◽  
Functional Trait ◽  
Forest Tree ◽  
Ecological Interactions ◽  
Trait Variation ◽  
Trade Offs ◽  
Spatiotemporal Scales ◽  
Evolutionary Consequences ◽  
Selection Of

All organisms experience fundamental conflicts between divergent metabolic processes. In plants, a pivotal conflict occurs between allocation to growth, which accelerates resource acquisition, and to defense, which protects existing tissue against herbivory. Trade-offs between growth and defense traits are not universally observed, and a central prediction of plant evolutionary ecology is that context-dependence of these trade-offs contributes to the maintenance of intraspecific variation in defense [Züst and Agrawal, Annu. Rev. Plant Biol., 68, 513–534 (2017)]. This prediction has rarely been tested, however, and the evolutionary consequences of growth–defense trade-offs in different environments are poorly understood, especially in long-lived species [Cipollini et al., Annual Plant Reviews (Wiley, 2014), pp. 263–307]. Here we show that intraspecific trait trade-offs, even when fixed across divergent environments, interact with competition to drive natural selection of tree genotypes corresponding to their growth–defense phenotypes. Our results show that a functional trait trade-off, when coupled with environmental variation, causes real-time divergence in the genetic architecture of tree populations in an experimental setting. Specifically, competitive selection for faster growth resulted in dominance by fast-growing tree genotypes that were poorly defended against natural enemies. This outcome is a signature example of eco-evolutionary dynamics: Competitive interactions affected microevolutionary trajectories on a timescale relevant to subsequent ecological interactions [Brunner et al., Funct. Ecol. 33, 7–12 (2019)]. Eco-evolutionary drivers of tree growth and defense are thus critical to stand-level trait variation, which structures communities and ecosystems over expansive spatiotemporal scales.

scholarly journals Cardiotonic Steroids and the Sodium Trade Balance: New Insights into Trade-Off Mechanisms Mediated by the Na+/K+-ATPase

2018 ◽  
Vol 19 (9) ◽  
pp. 2576 ◽  
Author(s):  
Fatimah Khalaf ◽  
Prabhatchandra Dube ◽  
Amal Mohamed ◽  
Jiang Tian ◽  
Deepak Malhotra ◽  
...  
Keyword(s):  
Volume Overload ◽  
Physiological Adaptation ◽  
Ion Pump ◽  
Trade Off ◽  
Trade Offs ◽  
Target Organs ◽  
Clinical Disorders ◽  
Adaptation Processes

In 1972 Neal Bricker presented the “trade-off” hypothesis in which he detailed the role of physiological adaptation processes in mediating some of the pathophysiology associated with declines in renal function. In the late 1990’s Xie and Askari published seminal studies indicating that the Na+/K+-ATPase (NKA) was not only an ion pump, but also a signal transducer that interacts with several signaling partners. Since this discovery, numerous studies from multiple laboratories have shown that the NKA is a central player in mediating some of these long-term “trade-offs” of the physiological adaptation processes which Bricker originally proposed in the 1970’s. In fact, NKA ligands such as cardiotonic steroids (CTS), have been shown to signal through NKA, and consequently been implicated in mediating both adaptive and maladaptive responses to volume overload such as fibrosis and oxidative stress. In this review we will emphasize the role the NKA plays in this “trade-off” with respect to CTS signaling and its implication in inflammation and fibrosis in target organs including the heart, kidney, and vasculature. As inflammation and fibrosis exhibit key roles in the pathogenesis of a number of clinical disorders such as chronic kidney disease, heart failure, atherosclerosis, obesity, preeclampsia, and aging, this review will also highlight the role of newly discovered NKA signaling partners in mediating some of these conditions.

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

The Effects of Decision Time on Perceptions of Decisions and Decision Makers in (Moral) Trade-Off Scenarios

2019 ◽  
Author(s):  
Anna Katharina Spälti ◽  
Mark John Brandt ◽  
Marcel Zeelenberg
Keyword(s):  
Decision Process ◽  
Decision Time ◽  
Decision Makers ◽  
Process Information ◽  
Total N ◽  
Trade Off ◽  
Financial Gain ◽  
Trade Offs ◽  
Sacred Values ◽  
Moral Context

People often have to make trade-offs. We study three types of trade-offs: 1) "secular trade-offs" where no moral or sacred values are at stake, 2) "taboo trade-offs" where sacred values are pitted against financial gain, and 3) "tragic trade-offs" where sacred values are pitted against other sacred values. Previous research (Critcher et al., 2011; Tetlock et al., 2000) demonstrated that tragic and taboo trade-offs are not only evaluated by their outcomes, but are also evaluated based on the time it took to make the choice. We investigate two outstanding questions: 1) whether the effect of decision time differs for evaluations of decisions compared to decision makers and 2) whether moral contexts are unique in their ability to influence character evaluations through decision process information. In two experiments (total N = 1434) we find that decision time affects character evaluations, but not evaluations of the decision itself. There were no significant differences between tragic trade-offs and secular trade-offs, suggesting that the decisions structure may be more important in evaluations than moral context. Additionally, the magnitude of the effect of decision time shows us that decision time, may be of less practical use than expected. We thus urge, to take a closer examination of the processes underlying decision time and its perception.

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