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| Author | Levionnois, Sébastien ; Ziegler, Camille ; Heuret, Patrick ; Jansen, Steven ; Stahl, Clément ; Calvet, Emma ; Goret, Jean-Yves ; Bonal, Damien ; Coste, Sabrina | ||||
| Title | Is vulnerability segmentation at the leaf‑stem transition a drought resistance mechanism? A theoretical test with a trait‑based model for Neotropical canopy tree species | Type | Journal Article | ||
| Year | 2021 | Publication | Annals of Forest Science | Abbreviated Journal | |
| Volume | 78 | Issue  |
4 | Pages | 78-87 |
| Keywords | Neotropics, bark, canopy, capacitance, drought, drought tolerance, embolism, leaves, models, transpiration, trees, tropical rain forests, xylem | ||||
| Abstract | Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stem. However, although it has been intensively investigated these past decades, the extent to which vulnerability segmentation promotes drought resistance is not well understood. Based on a trait-based model, this study theoretically supports that vulnerability segmentation enhances shoot desiccation time across 18 Neotropical tree species. CONTEXT: Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stems thereby preserving expensive organs such as branches or the trunk. Although vulnerability segmentation has been intensively investigated these past decades to test its consistency across species, the extent to which vulnerability segmentation promotes drought resistance is not well understood. AIMS: We investigated the theoretical impact of the degree of vulnerability segmentation on shoot desiccation time estimated with a simple trait-based model. METHODS: We combined data from 18 tropical rainforest canopy tree species on embolism resistance of stem xylem (flow-centrifugation technique) and leaves (optical visualisation method). Measured water loss under minimum leaf and bark conductance, leaf and stem capacitance, and leaf-to-bark area ratio allowed us to calculate a theoretical shoot desiccation time (tcᵣᵢₜ). RESULTS: Large degrees of vulnerability segmentation strongly enhanced the theoretical shoot desiccation time, suggesting vulnerability segmentation to be an efficient drought resistance mechanism for half of the studied species. The difference between leaf and bark area, rather than the minimum leaf and bark conductance, determined the drastic reduction of total transpiration by segmentation during severe drought. CONCLUSION: Our study strongly suggests that vulnerability segmentation is an important drought resistance mechanism that should be better taken into account when investigating plant drought resistance and modelling vegetation. We discuss future directions for improving model assumptions with empirical measures, such as changes in total shoot transpiration after leaf xylem embolism. | ||||
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| Publisher | Springer Link | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1034 | ||
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| Author | Baraloto, Christophier ; Vleminckx, Jason ; Engel, Julien ; Petronelli, Pascal ; Davila, Nallarett ; Rios, Marcos ; Valderrama Sandoval, Elvis Harry ; Mesones, Italo ; Guevara ANdino, Juan Ernesto ; Fortunel, Claire ; Allie, Elodie ; Paine, C.E. Timothy ; Dourdan, Aurélie ; Goret, Jean-Yves ; Valverde-Barrantes, Oscar J. ; Draper, Freddie ; Fine, Paul V. A. | ||||
| Title | Biogeographic history and habitat specialization shape floristic and phylogenetic composition across Amazonian forests | Type | Journal Article | ||
| Year | 2021 | Publication | Ecological Monographs | Abbreviated Journal | |
| Volume | 91 | Issue |
4 | Pages | e01473 |
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| Abstract | A major challenge remains to understand the relative contributions of history, dispersal, and environmental filtering to the assembly of hyperdiverse communities across spatial scales. Here, we examine the extent to which biogeographical history and habitat specialization have generated turnover among and within lineages of Amazonian trees across broad geographic and environmental gradients. We replicated standardized tree inventories in 102 0.1-ha plots located in two distant regions—the western Amazon and the eastern Guiana shield. Within each region, we used a nested design to replicate plots on contrasted habitats: white-sand, terra firme, and seasonally flooded forests. Our plot network encompassed 26,386 trees that together represented 2,745 distinct taxa, which we standardized across all plots and regions. We combined taxonomic and phylogenetic data with detailed soil measurements and climatic data to: (1) test whether patterns of taxonomic and phylogenetic composition are consistent with recent or historical processes, (2) disentangle the relative effects of habitat, environment, and geographic distance on taxonomic and phylogenetic turnover among plots, and (3) contrast the proportion of habitat specialists among species from each region. We found substantial species turnover between Peru and French Guiana, with only 8.8% of species shared across regions; genus composition remained differentiated across habitats and regions, whereas turnover at higher taxonomic levels (family, order) was much lower. Species turnover across plots was explained primarily by regions, but also substantially by habitat differences and to a lesser extent by spatial distance within regions. Conversely, the composition of higher taxonomic levels was better explained by habitats (especially comparing white-sand forests to other habitats) than spatial distance. White-sand forests harbored most of the habitat specialists in both regions, with stronger habitat specialization in Peru than in French Guiana. Our results suggest that recent diversification events have resulted in extremely high turnover in species and genus composition with relatively little change in the composition of higher lineages. Our results also emphasize the contributions of rare habitats, such as white-sand forests, to the extraordinary diversity of the Amazon and underline their importance as conservation priorities. | ||||
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| Publisher | Ecological Society of America | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1027 | ||
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| Author | Leponce, Maurice ; Dejean, Alain ; Mottl, Ondrej ; Klimes, Petr | ||||
| Title | Rapid assessment of the three-dimensional distribution of dominant arboreal ants in tropical forests | Type | Journal Article | ||
| Year | 2021 | Publication | Insect Conservation and Diversity | Abbreviated Journal | |
| Volume | 14 | Issue |
4 | Pages | 426-438 |
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| Abstract | Ants are omnipresent in tropical forests, especially territorially dominant arboreal ants whose territories are spatially segregated forming ‘ant mosaics’. These ecologically important species are rarely used in conservation monitoring because of the difficulty in collecting them. We developed a standardised baitline protocol to study the distribution of dominant ants on canopy trees and also a procedure to objectively define species dominance, even in unknown ant assemblages.
Besides eliminating the need to climb trees, this protocol allows live arboreal ant specimens to be sampled at different heights. Behavioural aggressiveness assays between the collected workers provide data on the three-dimensional distribution of colonies and on interactions between species. We compared the results of the behavioural tests to those from null models. In the New Guinean lowland forest studied, we show that the canopy was either shared by multiple territorial species or inhabited by a single species with a large territory. The baitline protocol collected up to half of the arboreal ant species found in a felling census. However, the proportion of species collected at baits decreased with the increasing spatial dominance of single territorial species. Behavioural observations used in the protocol allowed a more efficient detection of ant mosaics than null models. Territorially dominant ants were active on both understorey and canopy trees. The protocol is fast and easy to replicate. It is a potential tool for understanding and monitoring the spatiotemporal dynamics of arboreal ant assemblages and can detect populous colonies, including those of invasive species |
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| Publisher | Royal Entomological Society | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1047 | ||
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| Author | Schmitt, Sylvain ; Raevel, Valérie ; Réjou-Méchain, Maxime ; Ayyappan, Narayanan ; Balachandran, Natesan ; Barathan, Narayanan ; Rajashekar, Gopalakrishnan ; Munoz, François | ||||
| Title | Canopy and understorey tree guilds respond differently to the environment in an Indian rain forest | Type | Journal Article | ||
| Year | 2021 | Publication | Journal of Végétation Science | Abbreviated Journal | |
| Volume | 32 | Issue |
5 | Pages | e13075 |
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| Abstract | Questions Changes in the functional composition of tree communities along resource availability gradients have received attention, but it is unclear whether understorey and canopy guilds respond similarly to different light, biomechanical, and hydraulic constraints. Location An anthropically undisturbed, old-growth wet evergreen dipterocarp forest plot located in Karnataka State, India. Methods We measured leaf and wood traits of 89 tree species representing 99% of all individuals in a 10-ha permanent plot with varying topographic and canopy conditions inferred from Light Detection And Ranging (LiDAR) data. We assigned tree species to guilds of canopy and understorey species and assessed the variation of the guild-weighted means of functional-trait values with canopy height and topography. Results The functional-trait space did not differ between canopy and understorey tree species. However, environmental filtering led to significantly different functional composition of canopy and understorey guild assemblages. Furthermore, they responded differently along environmental gradients related to water, nutrients, light, and wind exposure. For example, the canopy guild responded to wind exposure while the understorey guild did not. Conclusions The pools of understorey and canopy species are functionally similar. However, fine-scale environmental heterogeneity impacts differently on these two guilds, generating striking differences in functional composition between understorey and canopy guild assemblages. Accounting for vertical guilds improves our understanding of forest communities' assembly processes. | ||||
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| Publisher | International Association for Vegetation Science | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1038 | ||
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| Author | Quéméré, Erwan ; Aucourt, Marie ; Troispoux, Valérie ; Brosse, Sébastien ; Murienne, Jérôme ; Covain, Raphael ; Le Bail, Pierre-Yves ; Olivier, Jean ; Tysklind, Niklas ; Galan, Maxime | ||||
| Title | Unraveling the dietary diversity of Neotropical top predators using scat DNA metabarcoding: A case study on the elusive Giant Otter | Type | Journal Article | ||
| Year | 2021 | Publication | Environmental DNA | Abbreviated Journal | |
| Volume | 3 | Issue |
5 | Pages | 889-900 |
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| Abstract | Large carnivores play a pivotal regulating role in maintaining healthy and balanced ecosystems; however, most of them are rare and elusive, and knowledge about their resource consumption is scarce. Traditional methods based on morphological identification of undigested remains are labor intensive and often not sufficiently accurate, leading to errors and biased ecological inferences. Here, we developed a multi-marker DNA metabarcoding approach to analyze the dietary diversity of giant otters (Pteronura brasiliensis) from fecal DNA while controlling predator species identity. We combined two mitochondrial markers, 12S rRNA and cytochrome c oxidase 1 (COI) gene, that target the full range of potential vertebrate and invertebrate prey. We compiled a local reference database of DNA barcodes for most potentially ingested fish, which were used to evaluate the specificity of the metabarcoding primers in silico. Most prey are identified at the species level (>90%) and the dietary profiles provided independently by the two markers are highly similar, whether in terms of list of prey or frequency of occurrences, hence validating the approach. We detected a higher number of rare fish prey with the 12S primers that amplified solely Teleost species while the degenerate COI primers revealed non-fish prey (e.g., amphibians, snakes, birds, and earthworms) and confirmed predator species identity. This study demonstrated that scat DNA metabarcoding is particularly useful to provide in-depth information on elusive carnivorous dietary profile. Our methodology opens up new opportunities to understand how top carnivores diet cope with the effects of anthropogenic alteration of ecosystems and identify conflicts with humans and livestock. | ||||
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| Publisher | Wiley | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1054 | ||
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| Author | Valverde-Barrantes, Oscar J. ; Authier, Louise ; Schimann, Heidy ; Baraloto, Christophier | ||||
| Title | Root anatomy helps to reconcile observed root trait syndromes in tropical tree species | Type | Journal Article | ||
| Year | 2021 | Publication | American Journal of Botany | Abbreviated Journal | |
| Volume | 108 | Issue |
5 | Pages | 744-755 |
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| Publisher | Botanical Society of America | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1056 | ||
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| Author | Bréchet, Laëtitia M.; Daniel Warren; Stahl, Clément; Burban, Benoït; Goret, Jean-Yves; Salomon, Roberto L.; Janssens, Ivan A.o | ||||
| Title | Simultaéneous tree stem and soil greenhouse gas (CO2, CH4, N2O) flux measurements: a novel design for continuous monitoring towards improving flux estimates and temporal resolution | Type | Journal Article | ||
| Year | 2021 | Publication | New Phytologist | Abbreviated Journal | |
| Volume | 230 | Issue |
6 | Pages | 2487-2500 |
| Keywords | système de chambre automatisé ; efflux de dioxyde de carbone ; flux de méthane ; flux d'oxyde nitreux ; tige d'arbre ; forêt tropicale | ||||
| Abstract | Tree stems and soils can act as sources and sinks for the greenhouse gases (GHG) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Since both uptake and emission capacities can be large, especially in tropical rainforests, accurate assessments of the magnitudes and temporal variations of stem and soil GHG fluxes are required. We designed a new flexible stem chamber system for continuously measuring GHG fluxes in a French Guianese rainforest. Here, we describe this new system, which is connected to an automated soil GHG flux system, and discuss measurement uncertainty and potential error sources. In line with findings for soil GHG flux estimates, we demonstrated that lengthening the stem chamber closure time was required for accurate estimates of tree stem CH4 and N2O flux but not tree stem CO2 flux. The instrumented stem was a net source of CO2 and CH4 and a weak sink of N2O. Our experimental setup operated successfully in situ and provided continuous tree and soil GHG measurements at a high temporal resolution over an 11-month period. This automated system is a major step forward in the measurement of GHG fluxes in stems and the atmosphere concurrently with soil GHG fluxes in tropical forest ecosystems. | ||||
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| Publisher | New Phytologist Foundation | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1004 | ||
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| Author | Coutant, Opale ; Richard-Hansen, Cecile ; de Thoisy, Benoit ; Decotte, Jean-Baptiste ; Valentini, Alice ; Dejean, Tony ; Vigouroux, Régis ; Murienne, Jérôme ; Brosse, Sébastien | ||||
| Title | Amazonian mammal monitoring using aquatic environmental DNA | Type | Journal Article | ||
| Year | 2021 | Publication | Molecular Ecology Resources | Abbreviated Journal | |
| Volume | 21 | Issue |
6 | Pages | 1875-1888 |
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| Abstract | Environmental DNA (eDNA) metabarcoding has emerged as one of the most efficient methods to assess aquatic species presence. While the method can in theory be used to investigate nonaquatic fauna, its development for inventorying semi-aquatic and terrestrial fauna is still at an early stage. Here we investigated the potential of aquatic eDNA metabarcoding for inventorying mammals in Neotropical environments, be they aquatic, semi-aquatic or terrestrial. We collected aquatic eDNA in 96 sites distributed along three Guianese watersheds and compared our inventories to expected species distributions and field observations derived from line transects located throughout French Guiana. Species occurrences and emblematic mammalian fauna richness patterns were consistent with the expected distribution of fauna and our results revealed that aquatic eDNA metabarcoding brings additional data to line transect samples for diurnal nonaquatic (terrestrial and arboreal) species. Aquatic eDNA also provided data on species not detectable in line transect surveys such as semi-aquatic, aquatic and nocturnal terrestrial and arboreal species. Although the application of eDNA to inventory mammals still needs some developments to optimize sampling efficiency, it can now be used as a complement to traditional surveys. | ||||
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| Publisher | Wiley | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1015 | ||
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| Author | Peterson, Michaela ; Jorge, Maria Luisa S.P. ; Jain, Avarna ; Keuroghlian, Alexine ; Oshima, Julia Emi F. ; Richard-Hansen, Cécile ; Berzins, Rachel ; Ribeiro, Milton Cezar ; Eaton, Don | ||||
| Title | Temperature induces activity reduction in a Neotropical ungulate | Type | Journal Article | ||
| Year | 2021 | Publication | Journal of Mammalogy | Abbreviated Journal | |
| Volume | 102 | Issue |
6 | Pages | 1-11 |
| Keywords | activity patterns, global warming, South America, thermoregulation, tropical forest, white-lipped peccaries | ||||
| Abstract | Because global climate change results in increasingly extreme temperatures and more frequent droughts, behavioral thermoregulation is one avenue by which species may adjust. Changes in activity patterns in response to temperature have been observed in a number of mammal species, but rarely have been investigated in humid tropical habitats. Here we examine the relationship between activity patterns and microclimate temperatures for white-lipped peccaries (Tayassu pecari, Tayassuidae, Cetartiodactyla) in four distinct biomes—the Cerrado, the Pantanal, the Atlantic Forest, and the Amazon. From 2013 to 2017, we monitored 30 white-lipped peccaries fitted with GPS collars that included accelerometers and temperature sensors. White-lipped peccaries were primarily diurnal, with peaks of activity in the morning and late afternoon, except in the Amazon where activity was high throughout the day. Total time active did not vary seasonally. White-lipped peccaries were significantly less likely to be active as temperatures increased, with the probability of being active decreasing by >49% in all biomes between 30 and 40°C. Our findings indicate that white-lipped peccaries are likely to be adversely impacted by rising temperatures, through being forced to reduce foraging time during their prime active periods. | ||||
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| Publisher | Oxford University Press | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1051 | ||
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| Author | Harper, Anna B. ; Williams, Karina E. ; McGuire, Patrick ; Duran Rojas, Maria Carolina ; Hemming, Debbie ; Verhoef, Anne ; Huntingford, Chris ; Rowland, Lucy ; Marthews, Toby ; Breder Eller, Cleiton ; Mathison, Camilla ; Nobrega, Rodolfo L.B. ; Gedney, Nicola ; Vidale, Pier Luigi ; Otu-Larbi, Fred ; Pandey, Divya | ||||
| Title | Improvement of modeling plant responses to low soil moisture in JULESvn4.9 and evaluation against flux tower measurements | Type | Journal Article | ||
| Year | 2021 | Publication | Geoscientific Model Development | Abbreviated Journal | |
| Volume | 14 | Issue |
6 | Pages | 3269-3294 |
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| Abstract | Drought is predicted to increase in the future due to climate change, bringing with it myriad impacts on ecosystems. Plants respond to drier soils by reducing stomatal conductance in order to conserve water and avoid hydraulic damage. Despite the importance of plant drought responses for the global carbon cycle and local and regional climate feedbacks, land surface models are unable to capture observed plant responses to soil moisture stress. We assessed the impact of soil moisture stress on simulated gross primary productivity (GPP) and latent energy flux (LE) in the Joint UK Land Environment Simulator (JULES) vn4.9 on seasonal and annual timescales and evaluated 10 different representations of soil moisture stress in the model. For the default configuration, GPP was more realistic in temperate biome sites than in the tropics or high-latitude (cold-region) sites, while LE was best simulated in temperate and high-latitude (cold) sites. Errors that were not due to soil moisture stress, possibly linked to phenology, contributed to model biases for GPP in tropical savanna and deciduous forest sites. We found that three alternative approaches to calculating soil moisture stress produced more realistic results than the default parameterization for most biomes and climates. All of these involved increasing the number of soil layers from 4 to 14 and the soil depth from 3.0 to 10.8 m. In addition, we found improvements when soil matric potential replaced volumetric water content in the stress equation (the “soil14psi” experiments), when the critical threshold value for inducing soil moisture stress was reduced (“soil14p0”), and when plants were able to access soil moisture in deeper soil layers (“soil14_dr*2”). For LE, the biases were highest in the default configuration in temperate mixed forests, with overestimation occurring during most of the year. At these sites, reducing soil moisture stress (with the new parameterizations mentioned above) increased LE and increased model biases but improved the simulated seasonal cycle and brought the monthly variance closer to the measured variance of LE. Further evaluation of the reason for the high bias in LE at many of the sites would enable improvements in both carbon and energy fluxes with new parameterizations for soil moisture stress. Increasing the soil depth and plant access to deep soil moisture improved many aspects of the simulations, and we recommend these settings in future work using JULES or as a general way to improve land surface carbon and water fluxes in other models. In addition, using soil matric potential presents the opportunity to include plant functional type-specific parameters to further improve modeled fluxes. | ||||
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| Publisher | European Geosciences Union | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 1057 | ||
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