Do mediterranean genera not included in Tachet et al. 2002 have mediterranean trait characteristics?

Multiple-trait databases are increasingly used in community ecology in different regions of the world. In Europe, Tachet et al. (2002) compiled an aquatic macroinvertebrate database for 473 taxa using information on 11 biological traits described by 63 categories. However, less studied regions, at the time of the compilation of the database, such as the mediterranean Basin, can harbour exclusive genera, which were not included in Tachet's database. In a large-scale study across the mediterranean Basin, we found 44 genera that were not included in Tachet's database (NEW genera). Our main aim was to compile trait information for these NEW genera and assess whether these genera had specific traits that could explain their exclusivity to theMediterranean region.We compared the trait characteristics of NEWgenera to those of genera only found in Mediterranean or temperate regions that were included in the Tachet's database (MED and TEM genera, respectively). We found that NEW genera had more mediterranean characteristics than TEM genera and that some trait categories of NEW genera were even more mediterranean-like than the traits of MED genera (e.g., diapause). Therefore, our results suggest that the specific biological traits of these NEW genera allow them to cope successfully and exclusively with the harsh environmental conditions of the mediterranean climate rivers, which could partially explain their absence in Tachet's database. Other explanations, such as the limited dispersal ability of these NEW genera to reach and colonize temperate Europe or the rarity of these NEW genera, should also be considered. We provide biological traits of the NEW genera to be used in future studies on the mediterranean river ecology.Las bases de datos de múltiples rasgos biológicos están siendo cada vez más utilizadas en ecología de comunidades en distintas regiones del mundo. En Europa, Tachet et al. (2002) recopilaron información de macroinvertebrados acuáticos para 473 taxones de 11 rasgos biológicos que incluyen 63 categorías. No obstante, es esperable que las regiones menos estudiadas durante la recopilación de datos, tales como las mediterráneas, alberguen géneros exclusivos que por falta de información no fueron incluidos inicialmente en la base de datos de Tachet. En un estudio a lo largo de la cuenca mediterránea, se encontraron 44 géneros no incluidos en la base de datos de Tachet (géneros NEW). Nuestro principal objetivo fue recoger información de estos géneros y analizar si tenían rasgos mediterráneos específicos que pudieran explicar su exclusividad en estos ambientes. Así, comparamos los rasgos de los géneros NEW con aquellos géneros encontrados en las regiones mediterráneas y templadas incluidos en la base de datos de Tachet (géneros MED y TEM, respectivamente). Los resultados mostraron que los géneros NEW tenían rasgos más mediterráneos que los géneros TEM, y que algunos de ellos incluso lo eran más que los de los géneros MED (e.g. diapausa). Por lo tanto, nuestros resultados sugieren que los rasgos específicos de estos géneros NEW les permiten hacer frente a las condiciones ambientales que caracterizan los ríos mediterráneos, lo que podría explicar, en parte, su ausencia en la base de datos de Tachet. Asimismo, se han considerado otras razones, tales como la limitada dispersión de estos géneros NEW para colonizar la Europa templada o su rareza. Se proporcionan los rasgos biológicos de estos géneros NEW para ser utilizados en futuros estudios en ríos de clima mediterráneo

Life-history strategies constrain invertebrate community tolerance to multiple stressors: A case study in the Ebro basin

AbstractContextMultiple stressors constitute a serious threat to aquatic ecosystems, particularly in the Mediterranean region where water scarcity is likely to interact with other anthropogenic stressors. Biological traits potentially allow the unravelling of the effects of multiple stressors. However, thus far, trait-based approaches have failed to fully deliver on their promise and still lack strong predictive power when multiple stressors are present.GoalWe aimed to quantify specific community tolerances against six anthropogenic stressors and investigate the responses of the underlying macroinvertebrate biological traits and their combinations.MethodsWe built and calibrated boosted regression tree models to predict community tolerances using multiple biological traits with a priori hypotheses regarding their individual responses to specific stressors. We analysed the combinations of traits underlying community tolerance and the effect of trait association on this tolerance.ResultsOur results validated the following three hypotheses: (i) the community tolerance models efficiently and robustly related trait combinations to stressor intensities and, to a lesser extent, to stressors related to the presence of dams and insecticides; (ii) the effects of traits on community tolerance not only depended on trait identity but also on the trait associations emerging at the community level from the co-occurrence of different traits in species; and (iii) the community tolerances and the underlying trait combinations were specific to the different stressors.ConclusionThis study takes a further step towards predictive tools in community ecology that consider combinations and associations of traits as the basis of stressor tolerance. Additionally, the community tolerance concept has potential application to help stream managers in the decision process regarding management options

Functional diversity: a review of methodology and current knowledge in freshwater macroinvertebrate research

Although several studies have examined the functional diversity of freshwater macroinvertebrates, the variety of methodologies combined with the absence of a synthetic review make our understanding of this field incomplete. Therefore, we reviewed the current methodology for assessing functional diversity in freshwater macroinvertebrate research. Our review showed that most papers quantified functional diversity using biological traits, among which feeding habits were the most common traits probably due to the assumed links between feeding and ecosystem functions. A large number of diversity measures have been applied for quantifying functional diversity of freshwater macroinvertebrate assemblages, among which Rao’s quadratic entropy looks like the most frequent. In most papers, functional diversity was positively related to taxon richness, and functional redundancy was a key concept in explaining this correlation. Most studies detected strong influence of the environmental factors as well as human impact on functional diversity. Finally, our review revealed that functional diversity research is biased towards European running waters and is hindered by yet insufficient information on the autecology of macroinvertebrates. © 2016 The Author(s

Ecological constraints from incumbent clades drive trait evolution across the tree-of-life of freshwater macroinvertebrates

The rates of species and trait diversification vary across the Tree‐of‐Life and over time. Whereas species richness and clade age generally are decoupled, the correlation of accumulated trait diversity of clades (trait disparity) with clade age remains poorly explored. Total trait disparity may be coupled with clade age if the growth of disparity (disparification) within and across clades is continuous with time in an additive niche expansion process (linear‐cumulative model), or alternatively if the rate of trait disparification varies over time and decreases as ecological space becomes gradually saturated (disparity‐dependent model). Using a clock‐calibrated phylogenetic tree for 143 freshwater macroinvertebrate families and richness and trait databases covering > 6400 species, we measured trait disparity in 18 independent clades that successively transitioned to freshwater ecosystems and analyzed its relation with clade age. We found a positive correlation between clade age and total disparity within clades, but no relationship for most individual traits. Traits unique to freshwater lifestyle were highly variable within older clades, while disparity in younger clades shifted towards partially terrestrial lifestyles and saline tolerance to occupy habitats previously inaccessible or underutilized. These results argue that constraints from incumbent lineages limit trait disparity in younger clades that evolved for filling unoccupied regions of the trait space, which suggests that trait disparification may follow a disparity‐dependent model. Overall, we provide an empirical pattern that reveals the potential of the disparity‐dependent model for understanding fundamental processes shaping trait dynamics across the Tree‐of‐Life

Combining taxon-by-trait and taxon-by-site matrices for analysing trait patterns of macroinvertebrate communities: a rejoinder to Monaghan & Soares (2014)

In a recent paper, Heino, Schmera & Erős (2013) provided an overview of trait 58 patterns of stream communities from a macroecological perspective. In this paper , 59 reference was made to Gayraud et al . (2003) , who showed that abundance - weighted 60 traits were less powe rful than presence - absence weighted traits in discriminating 61 communities under different degrees of human impacts , and to Statzner & Beche 62 (2010) , who therefore advocated the use of the second type of weighting for practical 63 biomonitoring due to logis tic constrains ( e.g. sorting of qualitative samples makes 64 3 assessment program me s more cost effective) . H eino et al . (2013) pointed out that 65 t hese findings contradict the results of taxon - based analyses which suggest that , if 66 taxa are weighted by their abund ance , then communities are better separated in 67 relation to environmental variation than when taxa are weighted only by their 68 presence . Based on an overview of the literature, Heino et al . (2013) concluded that 69 results of presence - and abundance - based analy ses should be evaluated carefully 70 when examining traits of organisms, because differences among studies can reflect 71 both methodological (i.e. handling of data) and real ecological differences (see p. 72 1549 in H eino et al ., 2013 ) . More recently, Monaghan & S oares (2014 ) stated that (1) 73 H eino et al . (2013) identified the weak explanatory power of abundance data as a 74 major limitation of macroinvertebrat e trait analysis and that (2) the log - transformation 75 of abundance data may cause anomalies in trait - based anal yses. W e disagree with 76 both conclusions , because (1) H eino et al . (2013) did not actually state this (see 77 above) and because (2), in our view, log - transformation of abundance data in trait - 78 based analyses can also be meaningful . To reveal the causes of thes e differ ing views , 79 we go through the examples provided by M onaghan & Soares (2014) and examine 80 how traits can be weighted by the presence, abundance and log - transformed 81 abundance of the taxa . To do this, firs t we define the terminology used here , comment 82 o n the approach of M onaghan & Soares (2014) and show how this procedure should 83 be performed

Analysis with respect to instrumental variables for the exploration of microarray data structures

BACKGROUND: Evaluating the importance of the different sources of variations is essential in microarray data experiments. Complex experimental designs generally include various factors structuring the data which should be taken into account. The objective of these experiments is the exploration of some given factors while controlling other factors. RESULTS: We present here a family of methods, the analyses with respect to instrumental variables, which can be easily applied to the particular case of microarray data. An illustrative example of analysis with instrumental variables is given in the case of microarray data investigating the effect of beverage intake on peripheral blood gene expression. This approach is compared to an ANOVA-based gene-by-gene statistical method. CONCLUSION: Instrumental variables analyses provide a simple way to control several sources of variation in a multivariate analysis of microarray data. Due to their flexibility, these methods can be associated with a large range of ordination techniques combined with one or several qualitative and/or quantitative descriptive variables

Biological traits of European pond macroinvertebrates

Whilst biological traits of river macroinvertebrates show unimodal responses to geographic changes in habitat conditions in Europe, we still do not know whether spatial turnover of species result in distinct combinations of biological traits for pond macroinvertebrates. Here, we used data on the occurrence of 204 macroinvertebrate taxa in 120 ponds from four biogeographic regions of Europe, to compare their biological traits. The Mediterranean, Atlantic, Alpine, and Continental regions have specific climate, vegetation and geology. Only two taxa were exclusively found in the Alpine and Continental regions, while 28 and 34 taxa were exclusively recorded in the Atlantic and Mediterranean regions, respectively. Invertebrates in the Mediterranean region allocated much energy to reproduction and resistance forms. Most Mediterranean invertebrate species had narrow thermal ranges. In Continental areas, invertebrates allocated lesser energy to reproduction and dispersal, and organisms were short lived with high diversity of feeding groups. These characteristics suggest higher resilience. The main difference between ponds in the Alpine and Atlantic regions was their elevation. Alpine conditions necessitate specific adaptations related to rapid temperature fluctuations, and low nutrient concentrations. Even if our samples did not cover the full range of pond conditions across Europe, our analyses suggest that changes in community composition have important impacts on pond ecosystem functions. Consistent information on a larger set of ponds across Europe would be much needed, but their low accessibility (unpublished data and/or not disclosed by authors) remains problematic. There is still, therefore, a pressing need for the incorporation of high quality data sets into a standardized database so that they can be further analyzed in an integrated European-wide manner

Effects of intense agricultural practices on heterotrophic processes in streams

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