Résumé

The rapidly growing number of grassroots ecological research networks demonstrates that ecologists have embraced distributed data collection and experimentation as a new tool for addressing global questions. A clear advantage of these networks is the ability to gather data at larger spatial and temporal scales and at relatively lower cost than could be typically accomplished by a single research team. However, a challenge arising from this structure is the need to merge distributed datasets into a coherent whole. The Nutrient Network, a coordinated distributed experiment entering its tenth year of data collection, has records from over 90 sites worldwide to date. In this paper I present lessons learned about data management from this project, focusing on such issues as standardization, storage, updates, and distribution of data within the network. I provide a relational database schema and associated workflow that could be generalized to many distributed ecological experiments or networked data observatories, especially those with need for taxonomic reconciliation of species occurrences. The success of distributed data collection efforts, especially long-term networks, will be proportional to the ability to coordinate and effectively combine project datasets.

Auteurs, date et publication :

Auteurs Eric M. Lind

Publication : Ecological Informatics

Date : 2016

Volume : 36

Pages : 231-236

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Résumé

Phenotypic effects of global warming have been documented in many different taxa. However, the importance of transgenerational phenotypic plasticity in these adaptations are seldom studied. In birds, temperature could affect egg characteristics. Higher temperatures during egg-laying may reduce maintenance costs for females and allow a higher investment in reproduction. Yet, females may also use temperatures as a cue for the risk of mismatch latter in the season. Thus, higher temperatures may be correlated to an acceleration of embryonic development (e.g. via hormonal manipulation). We performed an experiment in which night-time temperature was increased in the nestbox by approximately 1 degrees C throughout the entire laying period in great tits (Parus major). We collected one pre-treatment egg (beginning of the laying sequence) and one post-treatment egg (end of the laying sequence). Egg content (yolk androgens and lysozymes in the albumen), eggshell coloration, eggshell mass, egg mass, and shape were not affected by the treatment. However, last-laid eggs in clutches from control nestboxes had a thicker eggshell than last-laid eggs from heated nestboxes, suggesting a putative slight decrease of maternal investment with the experimental increase of temperature. We also observed effects of the laying sequence on egg characteristics. Eggs that were laid late in the laying sequence were heavier, larger, had larger spots and higher yolk androgens than eggs laid earlier. Lysozyme concentration decrease with the laying sequence in late clutches only. Thus, effects of temperature may also change with the laying sequence and it would be interesting in the future to tests the effects on first-laid eggs.

Auteurs, date et publication :

Auteurs Josefa Bleu , Simon Agostini , Frederic Angelier , Clotilde Biard

Publication : GENERAL AND COMPARATIVE ENDOCRINOLOGY

Date : 2019

Volume : 275

Pages : 73-81

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Résumé

Animals use a variety of strategies to avoid acute dehydration and death. Yet, how chronic exposure to sub-lethal dehydration may entail physiological and fitness costs remains elusive. In this study, we experimentally tested if water restriction causes increased oxidative stress (OS) and telomere length (TL) shortening, two well-described mediators of environment-fitness relationships. We exposed 100 yearling female and male common lizards (Zootoca vivipara) either to a 51-day period of water restriction or to water ad libitum, followed by 45 days in common garden outdoor conditions. We measured the kinetic changes in OS and TL and found that water-restricted males had enhanced antioxidant defences and decreased oxidative damage at day 36, whereas females did not immediately respond. A month and a half after water restriction, both sexes experienced a drop in antioxidant capacity but only males exhibited significant TL shortening. In the following 3 years, we found that lizards with longer initial TL and those who maintained stronger antioxidant defences experienced higher longevity, irrespective of sex and water restriction. Together, these results unravelled sex-specific responses to water restriction, with potential applications in better understanding the physiological costs of increasing summer droughts as a result of global climate change.

Auteurs, date et publication :

Auteurs Andreaz Dupoue , Frederic Angelier , Cecile Ribout , Sandrine Meylan , David Rozen-Rechels , Beatriz Decenciere , Simon Agostini , Jean-Francois Le Galliard

Publication : BIOLOGY LETTERS

Date : 2020

Volume : 16

Issue : 2

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Résumé

Urban habitat characteristics create environmental filtering of pollinator communities. They also impact pollinating insect phenology through the presence of an urban heat island and the year-round availability of floral resources provided by ornamental plants. Here, we monitored the phenology and composition of pollinating insect communities visiting replicates of an experimental plant assemblage comprising two species, with contrasting floral traits:Sinapis albaandLotus corniculatus, whose flowering periods were artificially extended. Plant assemblage replicates were set up over two consecutive years in two different habitats: rural and densely urbanized, within the same biogeographical region (Ile-de-France region, France). The phenology of pollination activity, recorded from the beginning (early March) to the end (early November) of the season, differed between these two habitats. Several pollinator morphogroups (small wild bees, bumblebees, honeybees) were significantly more active on our plant sets in the urban habitat compared to the rural one, especially in early spring and autumn. This resulted in different overall reproductive success of the plant assemblage between the two habitats. Over the course of the season, reproductive success ofS. albawas always significantly higher in the urban habitat, while reproductive success ofL. corniculatuswas significantly higher in the urban habitat only during early flowering. These findings suggest different phenological adaptations to the urban habitat for different groups of pollinators. Overall, results indicate that the broadened activity period of pollinating insects recorded in the urban environment could enhance the pollination function and the reproductive success of plant communities in cities.

Auteurs, date et publication :

Auteurs Vincent Zaninotto , Xavier Raynaud , Emmanuel Gendreau , Yvan Kraepiel , Eric Motard , Olivier Babiar , Amandine Hansart , Cecile Hignard , Isabelle Dajoz

Publication : ECOLOGY AND EVOLUTION

Date : 2020

Volume : 10

Issue : 20

Pages : 11607-11621

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Egg size has a crucial impact on the reproductive success of a mother and the performance of her offspring. It is therefore reasonable to employ egg size as a proxy for egg content when studying variation in offspring performance. Here, we tested species differences in allometries of several egg content parameters with egg area. We measured individual eggs in five species of annual killifish (Cyprinodontiformes), a group of fish where egg banks permit population survival over dry season. Apart from comparing allometric scaling exponents, amounts and compositions of egg components across the different species, we assessed the explanatory power of egg area for egg wet and dry weight and for hatchling size. We found notable species-specific allometries between egg area and the other egg parameters (egg dry weight and water content, elemental composition and triglyceride content). Across species, egg area predicted egg wet weight with highest power. Within species, coefficients of determination were largest in A. elongatus, a large piscivorous species with large eggs. Our study shows that systematically using egg area as a proxy of egg content between different species can ignore relevant speciesspecific differences and mask within-species variability in egg content.

Auteurs, date et publication :

Auteurs Milan Vrtilek , Tom J. M. Van Dooren , Megane Beaudard

Publication : COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY

Date : 2020

Volume : 249

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Résumé

Spatial rarity is often used to predict extinction risk, but rarity can also occur temporally. Perhaps more relevant in the context of global change is whether a species is core to a community (persistent) or transient (intermittently present), with transient species often susceptible to human activities that reduce niche space. Using 5-12 years of data on 1,447 plant species from 49 grasslands on 5 continents, we show that local abundance and species persistence under ambient conditions are both effective predictors of local extinction risk following experimental exclusion of grazers or addition of nutrients; persistence was a more powerful predictor than local abundance. While perturbations increased the risk of exclusion for low persistence and abundance species, transient but abundant species were also highly likely to be excluded from a perturbed plot relative to ambient conditions. Moreover, low persistence and low abundance species that were not excluded from perturbed plots tended to have a modest increase in abundance following perturbance. Lastly, even core species with high abundances had large decreases in persistence and increased losses in perturbed plots, threatening the long-term stability of these grasslands. Our results demonstrate that expanding the concept of rarity to include temporal dynamics, in addition to local abundance, more effectively predicts extinction risk in response to environmental change than either rarity axis predicts alone.

Auteurs, date et publication :

Auteurs Peter A. Wilfahrt , Ashley L. Asmus , Eric W. Seabloom , Jeremiah A. Henning , Peter Adler , Carlos A. Arnillas , Jonathan D. Bakker , Lori Biederman , Lars A. Brudvig , Marc Cadotte , Pedro Daleo , Anu Eskelinen , Jennifer Firn , W. Stanley Harpole , Yann Hautier , Kevin P. Kirkman , Kimberly J. Komatsu , Ramesh Laungani , Andrew MacDougall , Rebecca L. McCulley

Publication : Ecology

Date : 2025

Volume : n/a

Issue : n/a

Pages : e03504

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Résumé

Fertilisation experiments have demonstrated that nutrient availability is a key determinant of biomass production and carbon sequestration in grasslands. However, the influence of nutrients in explaining spatial variation in grassland biomass production has rarely been assessed. Using a global dataset comprising 72 sites on six continents, we investigated which of 16 soil factors that shape nutrient availability associate most strongly with variation in grassland aboveground biomass. Climate and N deposition were also considered. Based on theory-driven structural equation modelling, we found that soil micronutrients (particularly Zn and Fe) were important predictors of biomass and, together with soil physicochemical properties and C:N, they explained more unique variation (32%) than climate and N deposition (24%). However, the association between micronutrients and biomass was absent in grasslands limited by NP. These results highlight soil properties as key predictors of global grassland biomass production and point to serial co-limitation by NP and micronutrients.

Auteurs, date et publication :

Auteurs Dajana Radujković , Erik Verbruggen , Eric W. Seabloom , Michael Bahn , Lori A. Biederman , Elizabeth T. Borer , Elizabeth H. Boughton , Jane A. Catford , Matteo Campioli , Ian Donohue , Anne Ebeling , Anu Eskelinen , Philip A. Fay , Amandine Hansart , Johannes M. H. Knops , Andrew S. MacDougall , Timothy Ohlert , Harry Olde Venterink , Xavier Raynaud , Anita C. Risch

Publication : Ecology Letters

Date : 2025

Volume : 24

Issue : 12

Pages : 2713-2725

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Résumé

Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences.

Auteurs, date et publication :

Auteurs Jean-François Le Le Galliard , David Rozen-Rechels , Anjélica Lecomte , Clémence Demay , Andréaz Dupoué , Sandrine Meylan

Publication : PLOS ONE

Date : 2025

Volume : 16

Issue : 2

Pages : e0247514

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Résumé

A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-20997-9.

Auteurs, date et publication :

Auteurs Yann Hautier , Pengfei Zhang , Michel Loreau , Kevin R. Wilcox , Eric W. Seabloom , Elizabeth T. Borer , Jarrett E. K. Byrnes , Sally E. Koerner , Kimberly J. Komatsu , Jonathan S. Lefcheck , Andy Hector , Peter B. Adler , Juan Alberti , Carlos A. Arnillas , Jonathan D. Bakker , Lars A. Brudvig , Miguel N. Bugalho , Marc Cadotte , Maria C. Caldeira , Oliver Carroll

Publication : Nature Communications

Date : 2021

Volume : 12

Issue : 1

Pages : 630

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Résumé

Simple Summary Urbanization modifies the composition of all biological communities, including insect pollinator communities, but what is filtered out? To answer this question, we compared the pollinators and their morphological and behavioral characteristics between Paris green spaces and nearby rural grasslands. We monitored the pollinators foraging on identical plant plots in these two environments for two years, and from spring to fall. Pollinators in the city were relatively less diverse than their rural counterparts. They comprised fewer bees belonging to solitary or ground-nesting species, but the bees had a larger body size overall. These data add to the body of evidence of a filtering of pollinator communities by the urban environment, partly because the abundance and distribution of nesting and feeding resources are modified. Since the diversity of pollinators is important for plant pollination, such effects must be considered in order to preserve the insect pollinator community and maintain the pollination function despite the increasing urbanization of our landscapes. Even though urban green spaces may host a relatively high diversity of wild bees, urban environments impact the pollinator taxonomic and functional diversity in a way that is still misunderstood. Here, we provide an assessment of the taxonomic and functional composition of pollinator assemblages and their response to urbanization in the Paris region (France). We performed a spring-to-fall survey of insect pollinators in green spaces embedded in a dense urban matrix and in rural grasslands, using a plant setup standardized across sites and throughout the seasons. We compared pollinator species composition and the occurrence of bee functional traits over the two habitats. There was no difference in species richness between habitats, though urban assemblages were dominated by very abundant generalist species and displayed a lower evenness. They also included fewer brood parasitic, solitary or ground-nesting bees. Overall, bees tended to be larger in the city than in the semi-natural grasslands, and this trait exhibited seasonal variations. The urban environment filters out some life history traits of insect pollinators and alters their seasonal patterns, likely as a result of the fragmentation and scarcity of feeding and nesting resources. This could have repercussions on pollination networks and the efficiency of the pollination function.

Auteurs, date et publication :

Auteurs Vincent Zaninotto , Adrien Perrard , Olivier Babiar , Amandine Hansart , Cecile Hignard , Isabelle Dajoz

Publication : INSECTS

Date : 2021

Volume : 12

Issue : 3

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