Navegando por Autor "Basset, Yves"
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Item Arthropod diversity in a tropical forest.(2012) Basset, Yves; Cizek, Lukas; Cuénoud, Philippe; Didham, Raphael K.; Guilhaumon, François; Missa, Olivier; Novotny, Vojtech; Ødegaard, Frode; Roslin, Tomas; Schmidl, Jürgen; Tishechkin, Alexey K.; Winchester, Neville N.; Roubik, David W.; Aberlenc, Henri Pierre; Bail, Johannes; Barrios, Héctor; Bridle, Jonathan R.; Meneses, Gabriela Castaño; Corbara, Bruno; Curletti, Gianfranco; Rocha, Wesley Duarte da; Bakker, Domir De; Delabie, Jacques Hubert Charles; Dejean, Alain; Fagan, Laura L.; Floren, Andreas; Kitching, Roger L.; Medianero, Enrique; Miller, Scott E.; Oliveira, Evandro Gama de; Orivel, Jérôme; Pollet, Marc; Rapp, Mathieu; Ribeiro, Sérvio Pontes; Roisin, Yves; Schmidt, Jesper B.; Sørensen, Line L.; Leponce, MauriceMost eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields >60% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.Item Effects of sclerophylly and host choice on gall densities andherbivory distribution in an Australian subtropical forest.(2016) Ribeiro, Sérvio Pontes; Basset, YvesWe hypothesize that upper canopies contrast with the understorey vegetation in gall density and survival be-cause of greater mortality in the latter. We expect that high sclerophylly rates in the upper canopy leaves are a main cause ofsuch pattern, and more important than other environmental traits, for instance related to altitude. The study was con-ducted in Lamington National Park, Queensland, Australia. Four independent vertical cylindrical transects through theforest canopy and one equivalent, horizontal understorey transect (20 m long and 1 m in diameter) were sampled at dif-ferent altitude (300, 700, 900 and 1100 m above sea level) during two seasons. Total and damaged leaves were counted,and galls were collected and opened to determine if they were alive or what may have been the cause of death. Sclerophyllywas estimated as specific foliar mass. Out of 72 sampled plant species, 29 presented galls, of which the greatest densitieswere concentrated on seven host species. A significant increase in sclerophylly with increasing canopy stratum height wasobserved, but had no direct effect on gall distribution. Total and live galls were more abundant in the canopy than in theunderstor ey for all altitud es but 300 m, where a specific infestation on saplings of the canopy tree Arytera divaricata oc-curred. We found a positive gall establishment and survivorship in the upper canopy, along with a decrease in chewing her-bivory, which resulted in decreasing risks of gall death by herbivory. An overall high sclerophylly rate in both canopy andunderstorey and the total number of galled host species suggest that the plant community studied is prone to gall estab-lishment and evolution. However, a few hosts species with extreme infestation, such as A.divaricata and Ficus watkinsiana,override the community-wide effect of sclerophylly. Our results emphasize how scarce and patchy distributed galls are.Item Gall-forming and free-feeding herbivory along vertical gradients in a lowland tropical rainforest : the importance of leaf sclerophylly.(2007) Ribeiro, Sérvio Pontes; Basset, YvesIn contrast to most insect guilds, gall-forming insects are thought to reach highest diversity on sclerophyllous vegetation, such as Neotropical savannas and Mediterranean vegetation types. The water and nutrient stress endured by meristems of canopy trees in tall wet tropical rainforests may cause leaf sclerophylly. Hence, the upper canopies of such ecosystems may represent a suitable habitat for gall-forming insects. At the San Lorenzo Protected Area, Panama, we estimated free-feeding herbivory and gall densities within five sites in 2003 and 2004, by surveying leaves in vertical and horizontal transects. In each sample, we recorded leaf density (mature and young foliage), free-feeding herbivore damage and number of galls, including the presence of live larvae, parasitoids or fungi. We surveyed 43 994 leaves, including 231 plants and 73 tree and liana species. We collected 5014 galls from 17 host-plant species, including 32 gall species of which 59% were restricted to the canopy (overall infestation rates: 2.4% in 2003, 5.5% in 2004). In 2003, 16% of the galls were occupied by live larvae, against 5% in 2004. About 17 20% of leaves surveyed suffered from free-feeding herbivory. Leaf sclerophylly increased significantly with sampling height, while free-feeding herbivory decreased inversely. Conversely, the number of live galls collected in the canopy was 13 16 times higher than in the understorey, a pattern consistent across sites and years. Hence, the probability of gall survivorship increased with increasing leaf sclerophylly as death by fungi, parasitoids or accidental chewing were greater in the understorey. Increasing harsh ecophysiological conditions towards the upper canopy appear favourable to galls-forming population maintenance, in support of the hypothesis of harsh environment. Hence, gall diversity and abundance in the upper canopy of tall tropical forests are perhaps among the highest in the world.Item IBISCA-Panama, a large-scale study of arthropod beta-diversity and vertical stratification in a lowland rainforest : rationale, study sites and field protocols.(2007) Basset, Yves; Corbara, Bruno; Barrios, Héctor; Cuénoud, Philippe; Leponce, Maurice; Aberlenc, Henri Pierre; Bail, Johannes; Bito, Darren; Bridle, Jonathan R.; Castaño Meneses, Gabriela; Cizek, Lukas; Cornejo, Aydee; Curletti, Gianfranco; Delabie, Jacques Hubert Charles; Dejean, Alain; Didham, Raphael K.; Dufrêne, Marc; Fagan, Laura L.; Floren, Andreas; Frame, Dawn M.; Hallé, Francis; Hardy, Olivier J.; Hernandez, Andrés; Kitching, Roger L.; Lewinsohn, Thomas M.; Lewis, Owen T.; Medianero, Enrique; Missa, Olivier; Mitchell, Andrew W.; Mogia, Martin; Novotny, Vojtech; Ødegaard, Frode; Oliveira, Evandro Gama de; Orivel, Jérôme; Ozanne, laire M. P.; Pascal, Olivier; Pinzón, Sara; Rapp, Mathieu; Ribeiro, Sérvio Pontes; Roisin, Yves; Roslin, Tomas; Roubik, David W.; Samaniego, Mirna; Schmidl, Jürgen; Sørensen, Line L.; Tishechkin, Alexey K.; Osselaer, Christian Van; Winchester, Neville N.IBISCA-Panama (“Investigating the BIodiversity of Soil and Canopy Arthropods”, Panama module) represents a large-scale research initiative to quantify the spatial distribution of arthropod biodiversity in a Neotropical forest, using a combination of (1) international collaboration, (2) a set of common research questions, and (3) an integrated experimental design. Here, we present the rationale of the programme, describe the study sites, and outline field protocols. In the San Lorenzo Protected Area of Panama, twelve 20 x 20 m sites, all less than 2 km apart, were surveyed for plants and arthropods, from the ground to the upper canopy. Access to the canopy and its fauna was facilitated by fogging, single-rope techniques and a variety of devices such as a canopy crane, the “SolVin-Bretzel” canopy raft, the canopy bubble and Ikos. IBISCA-Panama represented the first attempt to combine these complementary techniques of canopy access in a large-scale investigation. Such techniques provided spatial replication during initial field work performed in September-October 2003. Temporal replication across seasons consisted of subsequent field work of varying intensity during dry, early wet and late wet periods in 2004. Arthropods were surveyed using 14 different protocols targeting the soil, litter, understorey, mid-canopy and upper canopy habitats. These protocols included: WINKLER sifting; BERLESE-TULLGREN; hand-collecting of galls and social insects; fogging; beating; woodrearing; baits; and various types of traps such as pitfall, small and large flight-interception, sticky, light, and Malaise traps. Currently, analyses of arthropod distribution in this forest concentrate on a set of 63 focal taxa representing different phylogenies and lifehistories. IBISCA-Panama may be considered as a model for largescale research programmes targeting invertebrate biodiversity. Its collaborative modus operandi can be applied to answer a variety of pressing ecological questions related to forest biodiversity, as evidenced by the recent development of further IBISCA programmes in other parts of the world.Item Spatial and functional structure of an entire ant assemblage in a lowland Panamanian rainforest.(2021) Leponcea, Maurice; Corbara, Bruno; Delabie, Jacques Hubert Charles; Orivel, Jérôme; Aberlenc, Henri Pierre; Bail, Johannes; Barrios, Héctor; Campos, Ricardo Ildefonso de; Nascimento, Ivan Cardoso do; Compin, Arthur; Didham, Raphael K.; Floren, Andreas; Medianero, Enrique; Ribeiro, Sérvio Pontes; Roisin, Yves; Schmidl, Juergen; Tishechkin, Alexey K.; Winchester, Neville N.; Basset, Yves; Dejean, AlainAnts are a major ecological group in tropical rainforests. Few studies in the Neotropics have documented the distribution of ants from the ground to the canopy, and none have included the understorey. A previous analysis of an intensive arthropod study in Panama, involving 11 sampling methods, showed that the factors influencing ant b diversity (i.e., changes in assem- blage composition) were, in decreasing order of importance, the vertical (height), temporal (season), and horizontal (geographic distance) dimensions. In the present study, we went one step further and aimed (1) to identify the best sampling methods to study the entire ant assemblage across the three strata, (2) to test if all strata show a similar horizontal b diversity and (3) to ana- lyze the functional structure of the entire ant assemblage. We identified 405 ant species from 11 subfamilies and 68 genera. Slightly more species were sampled in the canopy than on the ground; they belonged to distinct sub-assemblages. The under- storey fauna was mainly a mixture of species found in the other two strata. The horizontal b diversity between sites was similar for the three strata. About half of the ant species foraged in two (29%) or three (25%) strata. A single method, aerial flight inter- ception traps placed alongside tree trunks, acting as arboreal pitfall traps, collected half of the species and reflected the vertical stratification. Using the functional traits approach, we observed that generalist species with mid-sized colonies were by far the most numerous (31%), followed by ground- or litter-dwelling species, either specialists (20%), or generalists (16%), and arbo- real species, either generalists (19%) or territorially dominant (8%), and finally army ants (5%). Our results reinforce the idea that a proper understanding of the functioning of ant assemblages requires the inclusion of arboreal ants in survey programs. © 2021 Gesellschaft für Ökologie. Published by Elsevier GmbH. All rights reserved.