functional reduction in pollination through herbivore-induced pollinator limitation and its potential in mutualist communities
paul glaum, andré kessler 2017
flowering phenology shifts in response to biodiversity loss
amelia a. wolf, erika s. zavaleta, paul c. selmants 2017
Advanced spring flowering has been described as a fingerprint of climate change—a public, visible display of the detrimental effects of global warming. However, warming experiments fail to account for the full magnitude of observed changes in phenology, suggesting that other factors may play important roles. We show that peak flowering time shifts earlier for most species when we experimentally reduce plant diversity. Additionally, peak flowering times of plant species are more evenly distributed across the season in high-diversity plots. Overall, these results demonstrate the importance of biotic interactions in influencing flowering times and indicate that advancing phenology, one of the most well-described and well-publicized phenomena linking global warming to plant communities, may result equally from biodiversity declines.
Observational studies and experimental evidence agree that rising global temperatures have altered plant phenology—the timing of life events, such as flowering, germination, and leaf-out. Other large-scale global environmental changes, such as nitrogen deposition and altered precipitation regimes, have also been linked to changes in flowering times. Despite our increased understanding of how abiotic factors influence plant phenology, we know very little about how biotic interactions can affect flowering times, a significant knowledge gap given ongoing human-caused alteration of biodiversity and plant community structure at the global scale. We experimentally manipulated plant diversity in a California serpentine grassland and found that many plant species flowered earlier in response to reductions in diversity, with peak flowering date advancing an average of 0.6 days per species lost. These changes in phenology were mediated by the effects of plant diversity on soil surface temperature, available soil N, and soil moisture. Peak flowering dates were also more dispersed among species in high-diversity plots than expected based on monocultures. Our findings illustrate that shifts in plant species composition and diversity can alter the timing and distribution of flowering events, and that these changes to phenology are similar in magnitude to effects induced by climate change. Declining diversity could thus contribute to or exacerbate phenological changes attributed to rising global temperatures.
the lung is a site of platelet biogenesis and a reservoir for haematopoietic progenitors
emma lefrançais et al. 2017
a systematic review of ecological attributes that confer resilience to climate change in environmental restoration
britta l. timpane-padgham, tim beechie, terrie klinger 2017
contrasting responses of functional diversity to major losses in taxonomic diversity
stewart m. edie et al. 2017
Global biodiversity consists not only of the sum of taxonomic units such as species, but also of their ecological or functional variety. These two components of biodiversity might be expected to rise or fall in tandem, but we find they are capable of strikingly independent behavior. In three major declines in taxonomic diversity—spatially from equator to poles today and temporally in the Permian–Triassic and Cretaceous–Paleogene extinctions—only the first one shows a concomitant drop in the number of functional groups, whereas virtually all functional categories survived the extinction events. We present a conceptual framework for understanding this contrast, and we suggest that the differing behavior of these two biodiversity components will be important in anticipating the impacts of impending losses in today’s biota.
Taxonomic diversity of benthic marine invertebrate shelf species declines at present by nearly an order of magnitude from the tropics to the poles in each hemisphere along the latitudinal diversity gradient (LDG), most steeply along the western Pacific where shallow-sea diversity is at its tropical maximum. In the Bivalvia, a model system for macroevolution and macroecology, this taxonomic trend is accompanied by a decline in the number of functional groups and an increase in the evenness of taxa distributed among those groups, with maximum functional evenness (FE) in polar waters of both hemispheres. In contrast, analyses of this model system across the two era-defining events of the Phanerozoic, the Permian–Triassic and Cretaceous–Paleogene mass extinctions, show only minor declines in functional richness despite high extinction intensities, resulting in a rise in FE owing to the persistence of functional groups. We hypothesize that the spatial decline of taxonomic diversity and increase in FE along the present-day LDG primarily reflect diversity-dependent factors, whereas retention of almost all functional groups through the two mass extinctions suggests the operation of diversity-independent factors. Comparative analyses of different aspects of biodiversity thus reveal strongly contrasting biological consequences of similarly severe declines in taxonomic diversity and can help predict the consequences for functional diversity among different drivers of past, present, and future biodiversity loss.
uplift-driven diversification in the hengduan mountains, a temperate biodiversity hotspot
yaowu xinga, richard h. ree 2017
Why do so many species occur in mountains? A popular but little-tested hypothesis is that tectonic uplift creates environmental conditions (new habitats, dispersal barriers, etc.) that increase the rate at which resident species divide and evolve to form new ones. In China’s Hengduan Mountains region, a biodiversity hotspot uplifted over the last 8 million years, this rate does in fact show a significant increase during that time, relative to the rate for adjacent older mountains, and to the rate of species immigration. The Hengduan Mountains flora is thus made up disproportionately of species that evolved within the region during its uplift, supporting the original hypothesis and helping to explain the prevalence of mountains as global biodiversity hotspots.
A common hypothesis for the rich biodiversity found in mountains is uplift-driven diversification—that orogeny creates conditions favoring rapid in situ speciation of resident lineages. We tested this hypothesis in the context of the Qinghai–Tibetan Plateau (QTP) and adjoining mountain ranges, using the phylogenetic and geographic histories of multiple groups of plants to infer the tempo (rate) and mode (colonization versus in situ diversification) of biotic assembly through time and across regions. We focused on the Hengduan Mountains region, which in comparison with the QTP and Himalayas was uplifted more recently (since the late Miocene) and is smaller in area and richer in species. Time-calibrated phylogenetic analyses show that about 8 million y ago the rate of in situ diversification increased in the Hengduan Mountains, significantly exceeding that in the geologically older QTP and Himalayas. By contrast, in the QTP and Himalayas during the same period the rate of in situ diversification remained relatively flat, with colonization dominating lineage accumulation. The Hengduan Mountains flora was thus assembled disproportionately by recent in situ diversification, temporally congruent with independent estimates of orogeny. This study shows quantitative evidence for uplift-driven diversification in this region, and more generally, tests the hypothesis by comparing the rate and mode of biotic assembly jointly across time and space. It thus complements the more prevalent method of examining endemic radiations individually and could be used as a template to augment such studies in other biodiversity hotspots.
polygamy slows down population divergence in shorebirds
josephine d'urban jackson et al. 2017
zorba, spock, or voldemort?
matthew sweet 2017
To be rational is to make the seemingly right decision, for the seemingly right reason, at the seemingly right time.
Of course, the real question is, how do you know when you’ve found the “right” decision, reason and time? One way to go about discovering it, according to the evangelists of rationality, is to flatten the curve of human experience.
In Antifragile, Nassim Taleb makes a point about complex systems. He says that to thrive they need variety and novelty. For a complex system, randomness is a necessity.
This applies to the human body, a gloriously complex system. Muscles need a range of stimulation that varies in frequency, intensity and duration to be at their most strong and supple. Joints need to be moved through multiple planes under a variety of loads to retain their stability and mobility. The cardiovascular systems needs to be challenged and tested to be at its most effective. All this needs to be done, but not in an organised way. The human body needs random variety, not regimented variety.
diversity in information and how to process it
the type of intuition sonya is seeking seems to be the kind i have, but it comes with unexpected costs: taking everything in that you can means you do not have conscious access to everything, because it exceeds our conscious ability
sanity on the weird timeline
sonya mann 2017
“While journalists and other experts maintain that truth is basically facts added up, the reality is that all of us, to very different degrees, uncover our own facts and assimilate them to our pre-existing beliefs about what’s true and false, right and wrong,” Nathan Jurgensen wrote. “Even when people see the same information, it means radically different things to them.”
If the world looks weird to you and me today, that is not a matter for rueful laughter, it is a sign that we are probably badly wrong about lots of things.
And being totally wrong about how the world works is a threat to survival.
I never used to obsess about this, but it’s a tautology that you can’t see your own blind spots.
Adam Elkus put it simply: “The price of being able to not be overwhelmed by the world is to have a filter, a cartoon-like image of reality that we can use in our day-to-day lives.” Systems engineer Mathias Lafeldt wrote, “One reason we tend to look for a single, simple cause of an outcome is because the failure is too complex to keep it in our head. Thus we oversimplify without really understanding the failure’s nature and then blame particular, local forces or events for outcomes.”
What I need is intuition that relies on experience rather than belief. Intuition that is optimized for being a functional human being, one who has a variety of healthy engagement modes at her disposal, rather than intuition that is optimized for yielding intellectually consistent results.
Maybe flexibility and the ability to move fast are more useful than being right. Earlier I said, “I’d rather be uncertain than wrong, but I’d rather be right than uncertain.” Maybe being right isn’t just not everything — it’s not a thing at all. Although I’ve long accepted that truth is subjective on an academic level, it’s hard for me to let the idea go deep.
Is it okay for day-to-day normality to feel strange? Is it adaptive or safe to process the world that way? The answer I’ve come to is both yes and no. If reflecting on the absurdity is where the processing ends, then no, it isn’t adaptive or safe. But navigating meta-rationally with sensitive fingertips is adaptive, and epistemically safe, although not necessarily comfortable.
Truth is not objective; every paradigm is true through a particular lens. Certainty becomes irrelevant, because certainty requires a commitment to one viewpoint, which you refuse to grant. Incidentally, I find that this helps a lot in terms of maintaining emotional equanimity.
diversity goes beyond the ends or means dichotomy, the dichotomy described by sonya
arguing about how the world should burn
sonya mann 2017
Some constraint on one’s options is acceptable to most of us. We’re social creatures; we need companionship. Cooperating and specializing is also good for productivity, and therefore survival. When you decide to have governance, to codify the norms of your community, you’ve already decided to limit people’s freedom. Your next decision is what constraints you’re going to impose. What will you punish and what will you tax? What will you encourage and subsidize?
Content and process are two dueling answers to this question, championed by fighters who mostly don’t understand the cause they’ve been marshalled to defend. Those who espouse the content approach want to push people out when they don’t buy into the norms and beliefs of the majority. Those who espouse the process approach want to compel everyone to obey the same rules. Neither side will ever be satisfied as long as the other exists.
sarah perry 2015
resistance to malaria through structural variation of red blood cell invasion receptors
ellen m leffler et al. 2017
pharmacogenomics of gpcr drug targets
alexander s. hauser et al. 2017
•GPCRs targeted by FDA-approved drugs show genetic variation in the human population
•Genetic variation occurs in functional sites and may result in altered drug response
•We present an online resource of GPCR genetic variants for pharmacogenomics research
•Understanding variation in drug targets may help alleviate economic healthcare burden
Natural genetic variation in the human genome is a cause of individual differences in responses to medications and is an underappreciated burden on public health. Although 108 G-protein-coupled receptors (GPCRs) are the targets of 475 (∼34%) Food and Drug Administration (FDA)-approved drugs and account for a global sales volume of over 180 billion US dollars annually, the prevalence of genetic variation among GPCRs targeted by drugs is unknown. By analyzing data from 68,496 individuals, we find that GPCRs targeted by drugs show genetic variation within functional regions such as drug- and effector-binding sites in the human population. We experimentally show that certain variants of μ-opioid and Cholecystokinin-A receptors could lead to altered or adverse drug response. By analyzing UK National Health Service drug prescription and sales data, we suggest that characterizing GPCR variants could increase prescription precision, improving patients’ quality of life, and relieve the economic and societal burden due to variable drug responsiveness.
disease spread in age structured populations with maternal age effects
jessica clark, jennie s. garbutt, luke mcnally, tom j. little 2017
evolutionary dynamics of incubation periods
bertrand ottino-loffler et al. 2017
coevolution maintains diversity in the stochastic ‘kill the winner’ model
chi xue and nigel goldenfeld 2017
top predators determine how biodiversity is partitioned across time and space
benjamin van allen et al. 2017
cascading predator effects in a fijian coral reef ecosystem
douglas b. rasher et al. 2017
what songbirds could teach us about constructive tweeting
ofer tchernichovski 2017
crowd vocal learning induces vocal dialects in bats: playback of conspecifics shapes fundamental frequency usage by pups
yosef prat et al. 2017
has implications for diversity initiation and maintenance: both fast and slow needed
thinking, fast and slow
rate, not selectivity, determines neuronal population coding accuracy in auditory cortex
wensheng sun, dennis l. barbour
when evolution is not a slow dance but a fast race to survive
wendy orent 2017
biodiversity effects on ecosystem functioning in a 15-year grassland experiment: patterns, mechanisms, and open questions
wolfgang w. weisser et al. 2017
In the past two decades, a large number of studies have investigated the relationship between biodiversity and ecosystem functioning, most of which focussed on a limited set of ecosystem variables. The Jena Experiment was set up in 2002 to investigate the effects of plant diversity on element cycling and trophic interactions, using a multi-disciplinary approach. Here, we review the results of 15 years of research in the Jena Experiment, focussing on the effects of manipulating plant species richness and plant functional richness. With more than 85,000 measures taken from the plant diversity plots, the Jena Experiment has allowed answering fundamental questions important for functional biodiversity research.
First, the question was how general the effect of plant species richness is, regarding the many different processes that take place in an ecosystem. About 45% of different types of ecosystem processes measured in the ‘main experiment’, where plant species richness ranged from 1 to 60 species, were significantly affected by plant species richness, providing strong support for the view that biodiversity is a significant driver of ecosystem functioning. Many measures were not saturating at the 60-species level, but increased linearly with the logarithm of species richness. There was, however, great variability in the strength of response among different processes. One striking pattern was that many processes, in particular belowground processes, took several years to respond to the manipulation of plant species richness, showing that biodiversity experiments have to be long-term, to distinguish trends from transitory patterns. In addition, the results from the Jena Experiment provide further evidence that diversity begets stability, for example stability against invasion of plant species, but unexpectedly some results also suggested the opposite, e.g. when plant communities experience severe perturbations or elevated resource availability. This highlights the need to revisit diversity–stability theory.
Second, we explored whether individual plant species or individual plant functional groups, or biodiversity itself is more important for ecosystem functioning, in particular biomass production. We found strong effects of individual species and plant functional groups on biomass production, yet these effects mostly occurred in addition to, but not instead of, effects of plant species richness.
Third, the Jena Experiment assessed the effect of diversity on multitrophic interactions. The diversity of most organisms responded positively to increases in plant species richness, and the effect was stronger for above- than for belowground organisms, and stronger for herbivores than for carnivores or detritivores. Thus, diversity begets diversity. In addition, the effect on organismic diversity was stronger than the effect on species abundances.
Fourth, the Jena Experiment aimed to assess the effect of diversity on N, P and C cycling and the water balance of the plots, separating between element input into the ecosystem, element turnover, element stocks, and output from the ecosystem. While inputs were generally less affected by plant species richness, measures of element stocks, turnover and output were often positively affected by plant diversity, e.g. carbon storage strongly increased with increasing plant species richness. Variables of the N cycle responded less strongly to plant species richness than variables of the C cycle.
Fifth, plant traits are often used to unravel mechanisms underlying the biodiversity–ecosystem functioning relationship. In the Jena Experiment, most investigated plant traits, both above- and belowground, were plastic and trait expression depended on plant diversity in a complex way, suggesting limitation to using database traits for linking plant traits to particular functions.
Sixth, plant diversity effects on ecosystem processes are often caused by plant diversity effects on species interactions. Analyses in the Jena Experiment including structural equation modelling suggest complex interactions that changed with diversity, e.g. soil carbon storage and greenhouse gas emission were affected by changes in the composition and activity of the belowground microbial community. Manipulation experiments, in which particular organisms, e.g. belowground invertebrates, were excluded from plots in split-plot experiments, supported the important role of the biotic component for element and water fluxes.
Seventh, the Jena Experiment aimed to put the results into the context of agricultural practices in managed grasslands. The effect of increasing plant species richness from 1 to 16 species on plant biomass was, in absolute terms, as strong as the effect of a more intensive grassland management, using fertiliser and increasing mowing frequency. Potential bioenergy production from high-diversity plots was similar to that of conventionally used energy crops. These results suggest that diverse ‘High Nature Value Grasslands’ are multifunctional and can deliver a range of ecosystem services including production-related services.
A final task was to assess the importance of potential artefacts in biodiversity–ecosystem functioning relationships, caused by the weeding of the plant community to maintain plant species composition. While the effort (in hours) needed to weed a plot was often negatively related to plant species richness, species richness still affected the majority of ecosystem variables. Weeding also did not negatively affect monoculture performance; rather, monocultures deteriorated over time for a number of biological reasons, as shown in plant-soil feedback experiments.
To summarize, the Jena Experiment has allowed for a comprehensive analysis of the functional role of biodiversity in an ecosystem. A main challenge for future biodiversity research is to increase our mechanistic understanding of why the magnitude of biodiversity effects differs among processes and contexts. It is likely that there will be no simple answer. For example, among the multitude of mechanisms suggested to underlie the positive plant species richness effect on biomass, some have received limited support in the Jena Experiment, such as vertical root niche partitioning. However, others could not be rejected in targeted analyses. Thus, from the current results in the Jena Experiment, it seems likely that the positive biodiversity effect results from several mechanisms acting simultaneously in more diverse communities, such as reduced pathogen attack, the presence of more plant growth promoting organisms, less seed limitation, and increased trait differences leading to complementarity in resource uptake. Distinguishing between different mechanisms requires careful testing of competing hypotheses. Biodiversity research has matured such that predictive approaches testing particular mechanisms are now possible.
wolfgang w. weisser et
genetic diversity affects ecological performance and stress response of marine diatom populations
sjöqvist co, kremp a 2017
genotypic richness and dissimilarity opposingly affect ecosystem functioning
jousset a et al. 2017
jousset a et al. 2017 demonstrates a parallel of too much diversity: “increasing richness, without concomitantly increasing dissimilarity, can decrease ecosystem functioning in simple environments due to antagonistic interactions”
high functional diversity stimulates diversification in experimental microbial communities
alexandre jousset et al. 2016
diversity spurs diversification in ecological communities
calcagno v et al. 2017
niche tradeoffs, neutrality, and community structure: a stochastic theory of resource competition, invasion, and community assembly
david tilman 2004
tilman 2004 holds parallels for our diversity: do certain forms take more resources (attention etc) than others, and thus act to suppress other forms? “the low invasibility of high diversity communities is predicted to result not from diversity per se, but from the uniformly low levels of resources that occur in high-diversity communities created by stochastic competitive assembly”
epigenetic contribution to diversification
heinrich bentea and ortrun mittelsten scheid 2017
hybrid incompatibility caused by an epiallele
todd blevins et al. 2017
rarity and persistence
geerat j. vermeij, richard k. grosberg 2017
locally rare species influence grassland ecosystem multifunctionality
soliveres et al. 2016
plant soil feedback strength in relation to large-scale plant rarity and phylogenetic relatedness
anne kempel et al. 2018
combination cancer therapy can confer benefit via patient-to-patient variability without drug additivity or synergy
adam c. palmer, peter k. sorger 2017
•Anti-cancer drugs have variable efficacy within patient populations
•Drug combinations give each patient more chances that one drug could be effective
•Clinical efficacy of many combinations is accurately predicted without drug synergy
•Optimizing drug independence represents a new way to design cancer treatments
Combination cancer therapies aim to improve the probability and magnitude of therapeutic responses and reduce the likelihood of acquired resistance in an individual patient. However, drugs are tested in clinical trials on genetically diverse patient populations. We show here that patient-to-patient variability and independent drug action are sufficient to explain the superiority of many FDA-approved drug combinations in the absence of drug synergy or additivity. This is also true for combinations tested in patient-derived tumor xenografts. In a combination exhibiting independent drug action, each patient benefits solely from the drug to which his or her tumor is most sensitive, with no added benefit from other drugs. Even when drug combinations exhibit additivity or synergy in pre-clinical models, patient-to-patient variability and low cross-resistance make independent action the dominant mechanism in clinical populations. This insight represents a different way to interpret trial data and a different way to design combination therapies.
medicines ‘off-label’ to treat people with conditions that these drugs haven’t been tested on
leah shaffer 3017
reducing urban violence
magdalena cerdá et al. 2017
predicting responses to contemporary environmental change using evolutionary response architectures
rachael a. bay et al. 2017
peter ralph at uoregon
turkle and papert 1990
economy of scale: third partner strengthens a keystone ant-plant mutualism
kirsten m. prior, todd m. palmer 2018
hidden genetic variation shapes the structure of functional elements in drosophila
mahul chakraborty et al. 2017
whole-genome sequencing reveals the extent of heterozygosity in a preferentially self-fertilizing hermaphroditic vertebrate
luana s. f. lins et al. 2017
the way things are
variation in salinity tolerance between and within anadromous subpopulations of pike (esox lucius)
johanna sunde et al. 2018
destabilizing mutations encode nongenetic variation that drives evolutionary innovation
katherine l. petrie et al. 2018
is local biodiversity declining or not? a summary of the debate over analysis of species richness time trends
bradley j. cardinale et al. 2018
•Recent analyses of time-series data suggest biodiversity is not declining at local scales as often claimed.
•We argue existing time-series are inappropriate for testing hypotheses about biodiversity change.
•Datasets are low quality, lack spatial representation, and fail to account for key drivers of change.
•Failure to consider these problems has led to misinterpretations and unwarranted extrapolations.
•New analyses must use higher-quality datasets to test improved hypotheses about diversity change.
Recently, a debate has developed over how biodiversity is changing across the planet. While most researchers agree species extinctions are increasing globally due to human activity, some now argue that species richness at local scales is not declining as many biologists have claimed. This argument stems from recent syntheses of time-series data that suggest species richness is decreasing in some locations, increasing in others, but not changing on average. Critics of these syntheses (like us) have argued there are serious limitations of existing time-series datasets and their analyses that preclude meaningful conclusions about local biodiversity change. Specifically, authors of these syntheses have failed to account for several primary drivers of biodiversity change, have relied on data poor time-series that lack baselines needed to detect change, and have unreasonably extrapolated conclusions. Here we summarize the history of this debate, as well as key papers and exchanges that have helped clarify new issues and ideas. To resolve the debate, we suggest future researchers be more clear about the hypotheses of biodiversity change being tested, focus less on amassing large datasets, and more on amassing high-quality datasets that provide unambiguous tests of the hypotheses. Researchers should also keep track of the contributions that native versus non-native species make to biodiversity time trends, as these have different implications for conservation. Lastly, we suggest researchers be aware of pros and cons of using different types of data (e.g., time-series, spatial comparisons), taking care to resolve divergent results among sources to allow broader conclusions about biodiversity change.
biodiversity gains? the debate on changes in local- vs global-scale species richness
richard b. primack et al. 2018
inheritors of the earth: how nature is thriving in an age of extinction
chris roberts 2017
aggregated knowledge from a small number of debates outperforms the wisdom of large crowds
joaquin navajas et al. 2018
measuring the crowd within: probabilistic representations within individuals
edward vul, harold pashler 2008
one and done? optimal decisions from very few samples
the “fundamental attribution error” is rational in an uncertain world
drew walker, kevin smith, edward vul
why hiring the ‘best’ people produces the least creative results
scott e page 2018
groups of diverse problem solvers can outperform groups of high-ability problem solvers
lu hong and scott e. page 2004
the diversity bonus: how great teams pay off in the knowledge economy
scott e page 2017 9780691176888
the difference: how the power of diversity creates better groups, firms, schools, and societies
diversity and complexity
food availability drives plastic self-repair response in a basal metazoan- case study on the ctenophore mnemiopsis leidyi a. agassiz 1865
katharina tissy bading et al. 2017
what if driving force of evolution is not niche variability but need for diversity? eventually suitable diverse form arrives in niche and happens to be more suited than general or previous form, so comes by chance to be more in that niche. the different species we see in different niches arise not because of the niches themselves but because the species arise or arrive suited to the niche? really need to read darwin’s words closely on this, as the general perception is that a niche causes speciation.
species diversity can drive speciation
“diversity begets diversity' hypothesis (Hypothesis 2; Van Valen, 1973; Rohde, 1992; Gillooly et al., 2004; Emerson & Kolm, 2005 )”
“One recurring theme is how diversity drives further diversity: do species create opportunities for speciation (MacArthur 1972; Strong et al. 1984; Farrell et al. 1992; Emerson & Kolm 2005; Janz et al. 2006)?”
but this disputes it
They argued that this positive relationship indicates speciation drives species richness. However, this speciation-driven hypothesis has been challenged by several other studies (Cadena et al. 2005, Kiflawi et al. 2007, Pereira et al. 2007, Whittaker et al. 2007, Witt and Maliakal-Witt 2007, Birand and Howard 2008, Gruner et al. 2008). The point of debate is not so much about how speciation could promote species diversity (this is rather obvious) but about whether the endemics–diversity relationship is a reliable testimony of this speciation-driven hypothesis.