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PubMed2006

Functional diversity: back to basics and looking forward.

Functional diversity is a component of biodiversity that generally concerns the range of things that organisms do in communities and ecosystems. Here, we review how functional diversity can explain and predict the impact of organisms on ecosystems and thereby provide a mechanistic link between the two. Critical points in developing predictive measures of functional diversity are the choice of functional traits with which organisms are distinguished, how the diversity of that trait information is summarized into a measure of functional diversity, and that the measures of functional diversity are validated through quantitative analyses and experimental tests. There is a vast amount of trait information available for plant species and a substantial amount for animals. Choosing which traits to include in a particular measure of functional diversity will depend on the specific aims of a particular study. Quantitative methods for choosing traits and for assigning weighting to traits are being developed, but need much more work before we can be confident about trait choice. The number of ways of measuring functional diversity is growing rapidly. We divide them into four main groups. The first, the number of functional groups or types, has significant problems and researchers are more frequently using measures that do not require species to be grouped. Of these, some measure diversity by summarizing distances between species in trait space, some by estimating the size of the dendrogram required to describe the difference, and some include information about species' abundances. We show some new and important differences between these, as well as what they indicate about the responses of assemblages to loss of individuals. There is good experimental and analytical evidence that functional diversity can provide a link between organisms and ecosystems but greater validation of measures is required. We suggest that non-significant results have a range of alternate explanations that do not necessarily contradict positive effects of functional diversity. Finally, we suggest areas for development of techniques used to measure functional diversity, highlight some exciting questions that are being addressed using ideas about functional diversity, and suggest some directions for novel research.

Adaptation, Physiological↗

PubMed2025

Heterogeneous trait responses of Páramo plant species and community to experimental warming.

Understanding the impact of climate change on the functional trait composition (and hence ecosystem functioning) of tropical alpine regions is critical for predicting biodiversity responses. We tested the effects of a decade of warming on the morphological, chemical and genomic traits of Páramo species using open-top chambers (OTCs). We conducted vegetation surveys and collected samples from individuals inside and outside the OTC plots to estimate differences between treatments (warming versus control). Vegetation cover decreased over time in both treatments suggesting a potential decline in soil moisture in our study area. Warming led to a reorganization of the trait space and trait network structure. Species showed a wide range of responses to warming, with significant changes across different trait combinations. Nevertheless, we did not find significant differences in trait values or the direction of change between species whose percentage vegetation cover increased in OTC (or decreased less) over time, compared with control. Community-weighted mean values of plant height, leaf area, leaf dry matter content, genome size, leaf C and P, significantly increased over time only in OTC plots (i.e. traits associated with carbon storage and decomposition). While warming and reduced soil moisture lead to heterogeneous species responses without a clear winning trait strategy, changes at the community level may have important implications for Páramo ecosystem functioning.

Climate Change↗

PubMed2006

Mapping of quantitative trait loci for lactation persistency traits in German Holstein dairy cattle.

A whole genome scan to map quantitative trait loci (QTL) for persistency of milk yield (PMY), persistency of fat yield (PFY), persistency of protein yield (PPY) and persistency of milk energy yield (PEY) was performed in a granddaughter design in the German Holstein dairy cattle population. The analysis included 16 paternal half-sib families with a total of 872 bulls. The analysis was carried out for the first lactation and for the first three lactations combined using univariate weighted multimarker regression. Controlling the false discovery rate across traits and data sets at a level of 0.15 and treating the four persistency traits as different traits revealed 27 significant QTL. A total of 12 chromosomes showed significant QTL effects on a chromosomewise basis. The DGAT1 effect was highly significant for PPY and protein yield. A haplotype analysis using results of previous studies of the same design revealed a co-segregation of various persistency QTL and QTL affecting health traits like dystocia and stillbirth and functional traits like non-return rate 90 and somatic cell score.

Animals↗

PubMed2006

Phylogenetic structure of Floridian plant communities depends on taxonomic and spatial scale.

Consideration of the scale at which communities are defined both taxonomically and spatially can reconcile apparently contradictory results on the extent to which plants show phylogenetic niche conservatism. In plant communities in north central Florida, we collected species abundances in 55 0.1-ha plots in several state parks. When communities were defined narrowly to include a single phylogenetic lineage, such as Quercus, Pinus, or Ilex, neighbors tended to be less related than expected (phylogenetic overdispersion) or there was no pattern. If the same communities were defined more broadly, such as when all seed plants were included, neighbors tended to be more related than expected (phylogenetic clustering). These results provide evidence that species interactions among close relatives influence community structure, but they also show that niche conservatism is increasingly evident as communities are defined to include greater phylogenetic diversity. We also found that, as the spatial scale is increased to encompass greater environmental heterogeneity, niche conservatism emerges as the dominant pattern. We then examined patterns of trait evolution in relation to trait similarity within communities for 11 functional traits for a single phylogenetic lineage (Quercus) and for all woody plants. Among the oaks, convergent evolution of traits important for environmental filtering contributes to the observed pattern of phylogenetic overdispersion. At the broader taxonomic scale, traits tend to be conserved, giving rise to phylogenetic clustering. The shift from overdispersion to clustering can be explained by the increasing conservatism of traits at broader phylogenetic scales.

Biological Evolution↗

PubMed2005

Evidence for deficit in tasks of ventral, but not dorsal, prefrontal executive function as an endophenotypic marker for bipolar disorder.

BACKGROUND: Trait functional abnormalities in BD patients have only been reported in the ventral prefrontal cortex (VPFC). We examined whether deficits in VPFC-related inhibitory processes, but not dorsal prefrontal (DPFC) based executive functions, represent an endophenotypic marker for bipolar disorder I (BDI). METHODS: We used the Wisconsin Card Sorting Test (WCST), commonly associated with DPFC function, and the Hayling Sentence Completion Task (HSCT) which engages the VPFC. Performance on these tests of 43 healthy participants was compared to that of 10 remitted BDI patients and 15 of their unaffected offspring. RESULTS: Compared to healthy participants, patients and their offspring made more errors in the HSCT but offspring achieved more categories and made fewer perseverative errors in the WCST. CONCLUSIONS: Impaired response inhibition, predominantly a VPFC related function, may reflect familial predisposition to BDI while deficits in rule attainment, a DPFC based function, may be associated only with the clinical phenotype.

Adult↗

PubMed1987

Psychosocial independence and functional abilities: their relationship in adults with severe musculoskeletal impairments.

Personality traits, functional abilities, and demographic characteristics of 61 persons with severe musculoskeletal impairments were examined using a personality factors questionnaire, the Barthel Index, and a demographic questionnaire. Subjects were grouped by high or low scores on the personality factors scale (psychologic independence) and an independent living scale (social independence). Data were analyzed using correlations, chi-squares, analyses of variance, factor analyses, and discriminant analyses. Subjects with high psychologic independence tended to live in less restrictive settings, had fewer communication problems, and spent less time in comprehensive rehabilitation facilities. Those with high social independence tended to be married; have assertive, self-assured, and self-sufficient personalities; more education; and more earned income. Both groups of highly independent persons tended to have hired attendants, good health, and more transportation options. They were outgoing, predominantly female, and tended to perceive themselves as independent. Functional abilities were not significantly related to levels of psychologic and social independence.

Activities of Daily Living↗

PubMed1979

An approach to direct detection of sinus nodal activity in man.

We are reporting a series of 13 out of a total of 16 patients in whom sinus nodal activity was recorded with the use of intra-atrial electrodes, during diagnostic His-bundle electrocardiography investigations. The protocol consisted of the simultaneous monitoring of the following intra-atrial points: high right atrium, low lateral right atrium, left atrium and the His-bundle electrogram (HBE), which accompanied the detecting sonde placed as a loop in the superior vena cava, with the electrodes facing the sinus nodal area. This permitted an adequate assessment of the sequence of the depolarizing activity. All patients showed sinus nodal potentials preceding the initiation of the P-wave in the surface-EKG or the atrial potential in the high right atrial lead, respectively, in the range of 60 to 270 msec depending upon the functional status of the sinus node in each patient. Such waves were clearly separated from the initiation of the atrial potential by an isoelectric line and showed functional traits compatible with the S-A nodal functions, as many authors have previously reported in experimental animal models. The text contains a review of the relevant literature and discussion upon the diagnostic significance of this method in the assessment of sinus nodal disease.

Adult↗

PubMed2006

Conventional functional classification schemes underestimate the relationship with ecosystem functioning.

Studies linking the functional diversity of a biota to ecosystem functioning typically employ a priori classifications of species into hypothetically complementary groups. However, multiple alternate classifications exist in which the number of functional groups, the number of species per functional group, and the grouping of species differ from the a priori scheme. Without assessing the relative precision, or ability of an a priori scheme to accurately predict ecosystem functioning relative to its many alternatives, the validity and utility of analyses based on a single a priori classification scheme remains unclear. We examine the precision of a priori classifications used in 10 experimental grassland systems in Europe and the United States that have found evidence for a significant role of functional plant diversity in governing ecosystem function. The predictive precision of the a priori classifications employed in these studies was seldom significantly higher than the precision of random classifications. Post-hoc classification schemes that performed well in predicting ecosystem function resembled each other more with regard to species composition than average classifications, but there was still considerable variability in the manner in which these classification schemes grouped species. These results suggest that we need a more nuanced understanding of how the diversity of functional traits of species in an assemblage affects ecosystem functioning.

Classification↗

PubMed2026

Decoding microbial metabolic complementarity from individual traits to community structuring.

A fundamental challenge in microbiome research lies in elucidating the functional capacity of microbial communities through community membership and genomic data. As community structuring and emergent functional traits are determined by bacterial community metabolic networks, it is important to gain insights into the principles that govern bacteria-bacteria interactions. Here, we applied an integrative framework linking individual strain-level traits to community structuring in a simplified synthetic bacterial community (SSC8) that promotes the growth of ungrafted watermelon. By combining mono- and coculture assays with genome-scale metabolic modeling and metabolomic profiling of spent media, we characterized directional interactions and resource dependencies among community members. Our findings show that positive interactions dominated the community network, accounting for 55% of all pairwise combinations, indicating a high prevalence of growth-promoting effects among strains. Genome-scale metabolic modeling showed that functional divergence among strains enhanced the potential for metabolic complementarity as phylogenetic distance increased. Integrating metabolic modeling with metabolomics further suggested that Pseudomonas azotifigens Q6 not only benefited from all other community members, but also exhibited mutualistic interactions with the other three strains, with metabolite exchange involving compounds such as L-lysine and L-cysteine. Pseudomonas azotifigens Q6 acted as an important driver of community composition by affecting the abundance of several other consortium members in vitro. These findings highlight the role of metabolic complementarity in driving community structuring by promoting selective persistence of specific strains. Our work provides mechanistic insights into microbial interaction networks in vitro and offers a conceptual foundation for the rational design of functionally robust and plant-beneficial microbiomes.

Bacteria↗

PubMed2006

Impact of drought on productivity and water use efficiency in 29 genotypes of Populus deltoides x Populus nigra.

We examined the relationships among productivity, water use efficiency (WUE) and drought tolerance in 29 genotypes of Populus x euramericana (Populus deltoides x Populus nigra), and investigated whether some leaf traits could be used as predictors for productivity, WUE and drought tolerance. At Orléans, France, drought was induced on one field plot by withholding water, while a second plot remained irrigated and was used as a control. Recorded variables included stem traits (e.g. biomass) and leaf structural (e.g. leaf area) and functional traits [e.g. intrinsic water use efficiency (Wi) and carbon isotope discrimination (Delta)]. Productivity and Delta displayed large genotypic variability and were not correlated. Delta scaled negatively with Wi and positively with stomatal conductance under moderate drought, suggesting that the diversity for Delta was mainly driven by stomatal conductance. Most of the productive genotypes displayed a low level of drought tolerance (i.e. a large reduction of biomass), while the less productive genotypes presented a large range of drought tolerance. The ability to increase WUE in response to water deficit was necessary but not sufficient to explain the genotypic diversity of drought tolerance.

Biomass↗

PubMed1999

Sustaining Ecosystem Services in Human-Dominated Watersheds: Biohydrology and Ecosystem Processes in the South Platte River Basin.

/ Sustaining ecosystem services important to humans while providing a dependable water supply for agriculture and urban needs is a major challenge faced by managers of human-dominated watersheds. Modification of natural flow regimes alters the abundance and composition of native plant and animal communities, affecting ecosystem services such as water storage and nutrient cycling that depend on particular species or functional groups. Because complete restoration of natural hydrology is generally not an option in human-dominated watersheds, there is a need to determine which specific flow manipulations are necessary to restore species-dependent ecosystem services in particular systems. Here we propose a framework for predicting ecological consequences of flow manipulations that is based on the role of hydrology in linking population, community, and ecosystem processes. We use a case-study approach to examine how interactions among the flow regime and species' functional traits help organize local biotic communities and generate alternate states of ecosystem functioning. Results indicate the importance of integrating hydrology and biology to predict ecological consequences of flow regime manipulations and the need to apply general flow-restoration principles on a case-by-case basis.KEY WORDS: Biohydrology; Aquatic ecosystems; Community assembly; Ecological integrity; Watershed restoration; Ecosystem serviceshttp://link.springer-ny.com/link/service/journals/00267/bibs/24n1p39.html

Journal Article↗

PubMed2009

Peptide YY (PYY) gene polymorphisms in the 3'-untranslated and proximal promoter regions regulate cellular gene expression and PYY secretion and metabolic syndrome traits in vivo.

RATIONALE: Obesity is a heritable trait that contributes to hypertension and subsequent cardiorenal disease risk; thus, the investigation of genetic variation that predisposes individuals to obesity is an important goal. Circulating peptide YY (PYY) is known for its appetite and energy expenditure-regulating properties; linkage and association studies have suggested that PYY genetic variation contributes to susceptibility for obesity, rendering PYY an attractive candidate for study of disease risk. DESIGN: To explore whether common genetic variation at the human PYY locus influences plasma PYY or metabolic traits, we systematically resequenced the gene for polymorphism discovery and then genotyped common single-nucleotide polymorphisms across the locus in an extensively phenotyped twin sample to determine associations. Finally, we experimentally validated the marker-on-trait associations using PYY 3'-untranslated region (UTR)/reporter and promoter/reporter analyses in neuroendocrine cells. RESULTS: Four common genetic variants were discovered across the locus, and three were typed in phenotyped twins. Plasma PYY was highly heritable (P < 0.0001), and genetic pleiotropy was noted between plasma PYY and body mass index (BMI) (P = 0.03). A PYY haplotype extending from the proximal promoter (A-23G, rs2070592) to the 3'-UTR (C+1134A, rs162431) predicted not only plasma PYY (P = 0.009) but also other metabolic syndrome traits. Functional studies with transfected luciferase reporters confirmed regulatory roles in altering gene expression for both 3'-UTR C+1134A (P < 0.001) and promoter A-23G (P = 0.0016). CONCLUSIONS: Functional genetic variation at the PYY locus influences multiple heritable metabolic syndrome traits, likely conferring susceptibility to obesity and subsequent cardiorenal disease.

3' Untranslated Regions↗

PubMed2003

Partitioning of water and nitrogen in co-occurring Mediterranean woody shrub species of different evolutionary history.

We studied the interspecific and intraspecific variation in the development of water stress and in the use of different water and nitrogen sources during the spring (wet season) and summer (dry season) in a shrub community in NE Spain. We measured shoot water potentials, stable deuterium isotopic composition (delta D) of xylem sap, leaf mass per area, leaf N and C concentrations, gas exchange, leaf delta(13)C, and leaf delta(15)N of the dominant species (Quercus coccifera, Arbutus unedo, Pistacia lentiscus, Erica multiflora, Globularia alypum). The delta D, the delta(13)C and the shoot water potential values showed diurnal, seasonal, intraspecific and interspecific variation in the source and use of water. There was also seasonal, intraspecific and interspecific variation in the foliar delta(15)N and N concentrations. In summer, some species (A. unedo, P. lentiscus and E. multiflora) presented significantly different delta D values in morning and afternoon measurements likely indicating that they used different sources of water during the day, and a dual root system in these species. We conjecture that dew may be one of these water sources. Species predawn water potential was negatively correlated with species xylem water delta D. There was also a positive correlation between delta(13)C and delta D in P. lentiscus, species for which we took additional samples from nearby sites. These results suggest that the access to water from greater depths allowed the maintenance of more favourable plant water supply. Multivariate principal component analysis based on the studied hydrological and isotope variables clearly separated the seasons (wet spring and dry summer) and the species. The species resulted separated according to their evolutionary history (Pre-Mediterranean and Mediterranean) and the associated root and functional traits. These results show water (and nitrogen) partitioning among coexisting species of the same functional type (Mediterranean woody shrubs). They also show the great intraspecific plasticity of responses to resource availability.

Carbon↗

PubMed1985

Genetic parameters and environmental factors associated with type traits scored on an ordered scale during first lactation.

Sixty subjective and linearized type data were recorded on 7375 first lactation Holstein cows. Data were analyzed by paternal half-sister analysis for genetic parameters. One hundred and six sires were represented. Two kinds of heritability estimates were obtained; the first was a method 3-derived estimate for the raw scale and the second was a "nonlinear method 3"-derived estimate for an underlying scale. Whenever estimates of heritability on the raw scale were positive, larger estimates were generally obtained on the underlying scale. Some udder traits (e.g., depth, rear length, rear balance, teat placement, rear teat length, rear width) had underlying heritabilities between 10 to 30%. Suspensory strength and teat shape had no genetic variation. Of feet and leg traits only set (.14) and cleanness of hocks (.09) had heritabilities above 6%. Some functional traits (milking speed, edema) had heritabilities near 11%. Disposition, mastitis score, and milk letdown had no genetic variation. Most body traits (e.g., pin and hip width, length and levelness of rump, rib spring) had heritabilities between 15 and 30%. Method 3 phenotypic and genetic correlations relations were computed for the raw scale. Most phenotypic correlations were near zero. Traits associated with size or skeletal dimension had positive phenotypic typic and genetic correlations. Fore udder length, rear udder width, and rear udder height had positive genetic correlations (range .21 to .43). Udder depth had moderate genetic correlations with most udder traits, teat traits and body traits. The statistical models included describer, stage of lactation, and calendar month of description effects. In general, describer effects were the largest and most significant kind of environmental effect. Stage of lactation effects occasionally showed consistent trends. Month effects appeared to be unpredictable.

Animals↗

PubMed2004

Microbial structural diversity estimated by dilution-extinction of phenotypic traits and T-RFLP analysis along a land-use intensification gradient.

The present work tested whether the relationship between functional traits and inoculum density reflected structural diversity in bacterial communities from a land-use intensification gradient applying a mathematical model. Terminal restriction fragment length polymorphism (T-RFLP) analysis was also performed to provide an independent assessment of species richness. Successive 10-fold dilutions of a soil suspension were inoculated onto Biolog GN(R) microplates. Soil bacterial density was determined by total cell and plate counts. The relationship between phenotypic traits and inoculum density fit the model, allowing the estimation of maximal phenotypic potential (Rmax) and inoculum density (KI) at which Rmax will be half-reduced. Though Rmax decreased with time elapsed since clearing of native vegetation, KI remained high in two of the disturbed sites. The genetic pool of bacterial community did not experience a significant reduction, but the active fraction responding in the Biolog assay was adversely affected, suggesting a reduction in the functional potential.

Bacteria↗

PubMed1990

Functional and dysfunctional impulsivity: personality and cognitive correlates.

The 3 studies reported here were designed to clarify the nature of the personality trait of impulsivity. Two types of impulsivity were distinguished. Dysfunctional impulsivity is the tendency to act with less forethought than most people of equal ability when this tendency is a source of difficulty; most previous work on impulsivity appears to have focused on this trait. Functional impulsivity, in contrast, is the tendency to act with relatively little forethought when such a style is optimal. The present work indicates that these two tendencies are not highly correlated and that they bear different relations both to other personality traits and to the manner in which certain basic cognitive processes are executed.

Adult↗

PubMedDate not supplied

Genetics of resistance to mastitis in dairy cattle.

Genetic variability of mastitis resistance is well established in dairy cattle. Many studies focused on polygenic variation of the trait, by estimating heritabilities and genetic correlation among phenotypic traits related to mastitis such as somatic cell counts and clinical cases. The role of Major Histocompatibility Complex in the susceptibility or resistance to intrammamary infection is also well documented. Finally, development from molecular genome mapping led to accumulating information of quantitative trait loci (QTL) related to mastitis resistance and better understanding of the genetic determinism of the trait. From economic and genetic analyses, and according to welfare and food safety considerations and to breeders and consumer's concern, there is more and more evidence that mastitis should be included in breeding objective of dairy cattle breeds. Many countries have implemented selection for mastitis resistance based on linear decrease of somatic cell counts. Given biological questioning, potential unfavourable consequences for very low cell counts cows are regularly investigated. Improvement of selection accuracy for mastitis resistance is ongoing and includes: advances in modelling, optimal combination of mastitis related traits and associated predictors, such as udder morphology, definition of global breeding objective including production and functional traits, and inclusion of molecular information that is now available from QTL experiments.

Animals↗

PubMed2005

Genetics of parity-dependant production increase and its relationship with health, fertility, longevity, and conformation in swiss holsteins.

Genetic analysis of production increase (ProdI), defined as an increase in production from early to later lactations, was conducted using data from the Holstein Association of Switzerland. This production increase describes the maturity rate of the cow. The data set contained 42,807 cows with a ProdI value. All cows had completed the first 3 lactations. Different formulas were derived for the computation of ProdI using 1) milk yields or energy-corrected milk yields and 2) yields from all 3 lactations or only 2 of them (first and second, first and third, second and third). Heritabilities of ProdI and genetic and phenotypic correlations of ProdI with somatic cell score, days to first service, nonreturn rate, longevity, and 27 conformation traits were estimated by univariate and bivariate sire models that included relationship among sires. Heritabilities for ProdI were low (0.06 to 0.08), but genetic variation among sires existed. For nonreturn rate and longevity, regressions on the sire estimated breeding values were estimated. Additive genetic correlations of ProdI were moderately favorable with somatic cell score (-0.22 to -0.33) and chest width (0.21 to 0.30), i.e., with traits often associated with long-lasting cows. Unfavorable correlations were found with angularity (-0.18 to -0.26). Regression coefficients from regressing ProdI on sire estimated breeding values for longevity tend to show favorable relationships between these 2 traits (0.10 to 0.20). Results show that animals can be selected for ProdI, as there is good genetic variation between bulls. ProdI is a potential trait to be included in selection indices, as it has favorable genetic relationships with economically important functional traits such as health, conformation, and longevity.

Aging↗