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| Author | Herault, B.; Beauchene, J.; Muller, F.; Wagner, F.; Baraloto, C.; Blanc, L.; Martin, J.M. | ||||
| Title | Modeling decay rates of dead wood in a neotropical forest | Type | Journal Article | ||
| Year | 2010 | Publication  |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 164 | Issue | 1 | Pages | 243-251 |
| Keywords | Amazonia; Carbon cycle; Decomposition; Selective logging; Rainforest; Coarse woody debris | ||||
| Abstract | Variation of dead wood decay rates among tropical trees remains one source of uncertainty in global models of the carbon cycle. Taking advantage of a broad forest plot network surveyed for tree mortality over a 23-year period, we measured the remaining fraction of boles from 367 dead trees from 26 neotropical species widely varying in wood density (0.23-1.24 g cm(-3)) and tree circumference at death time (31.5-272.0 cm). We modeled decay rates within a Bayesian framework assuming a first order differential equation to model the decomposition process and tested for the effects of forest management (selective logging vs. unexploited), of mode of death (standing vs. downed) and of topographical levels (bottomlands vs. hillsides vs. hilltops) on wood decay rates. The general decay model predicts the observed remaining fraction of dead wood (R (2) = 60%) with only two biological predictors: tree circumference at death time and wood specific density. Neither selective logging nor local topography had a differential effect on wood decay rates. Including the mode of death into the model revealed that standing dead trees decomposed faster than downed dead trees, but the gain of model accuracy remains rather marginal. Overall, these results suggest that the release of carbon from tropical dead trees to the atmosphere can be simply estimated using tree circumference at death time and wood density. | ||||
| Address | [Herault, Bruno; Wagner, Fabien; Martin, Jean-Michel] Univ Antilles Guyane, UMR EcoFoG, F-97387 Kourou, France, Email: bruno.herault@ecofog.gf | ||||
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| Publisher | SPRINGER | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0029-8549 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | ISI:000280962200023 | Approved | no | ||
| Call Number | EcoFoG @ eric.marcon @ | Serial | 45 | ||
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| Author | Paine, C.E.T.; Harms, K.E. | ||||
| Title | Quantifying the effects of seed arrival and environmental conditions on tropical seedling community structure | Type | Journal Article | ||
| Year | 2009 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 160 | Issue | 1 | Pages | 139-150 |
| Keywords | Community assembly; Dispersal; Niche differentiation; Seed addition; Variance partitioning | ||||
| Abstract | Though it is recognized that both stochastic and deterministic processes structure all communities, empirical assessments of their relative importance are rare, particularly within any single community. In this paper, we quantify the dynamic effects of dispersal assembly and niche assembly on the seedling layer in a diverse neotropical rain forest. The two theories make divergent predictions regarding the roles of seed arrival and environmental heterogeneity in generating community structure. Put simply, dispersal assembly posits that the stochasticity inherent to seed arrival structures communities, whereas niche assembly suggests that heterogeneity in post-dispersal environmental conditions is more important. We experimentally sowed 15,132 seeds of eight tree species at varying levels of density and diversity. Every six months we censused the seedlings that germinated and assessed the abiotic and biotic conditions of each plot. We assessed the density, diversity, and species composition of three nested subsets of the seedling layer: seedlings germinated from sown seeds, all seedlings germinated between July 2003 and 2004, and all woody seedlings. We partitioned the variance in density and diversity of each subset of the seedling layer into components representing seed-addition treatments and environmental conditions at 6- to 12-month intervals. Seed additions initially explained more variance in the density and diversity than did environmental heterogeneity for seven of eight sown species, but explained little variance in the density or diversity of the entire seedling layer. Species composition was better explained by seed-addition treatments than by environmental heterogeneity for all three subsets and in all time periods. Nevertheless, the variance in community structure explained by seed-addition treatments declined over the two years following germination, presaging shifts in the relative importance of dispersal assembly and niche assembly. Our study quantifies how dispersal assembly and niche assembly may vary among the components of an ecological community and shift dynamically through time. | ||||
| Address | [Paine, C. E. Timothy; Harms, Kyle E.] Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA, Email: timothy.paine@ecofog.gf | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0029-8549 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | ISI:000265100500014 | Approved | no | ||
| Call Number | EcoFoG @ eric.marcon @ | Serial | 116 | ||
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| Author | Baraloto, C.; Goldberg, D.E. | ||||
| Title | Microhabitat associations and seedling bank dynamics in a neotropical forest | Type | Journal Article | ||
| Year | 2004 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 141 | Issue | 4 | Pages | 701-712 |
| Keywords | French Guiana; life history traits; light availability; regeneration niche; soil nutrients | ||||
| Abstract | We conducted a rigorous test of tropical tree seedling microhabitat differentiation by examining microhabitat associations, survival and growth of established seedlings of ten tropical tree species representing a four-factor gradient in seed size. Eight microhabitat variables describing soil and light conditions were measured directly adjacent to each of 588 seedlings within twelve 10 x 100 m belt transects at Paracou, French Guiana, and at 264 reference points along the transects. From these measurements, we defined three principal components describing soil richness, soil softness and canopy openness. Six of ten species ( in 9 of 30 total cases) were distributed non-randomly with respect to microhabitat along at least one principal component. However, few species demonstrated clear microhabitat specialization. All shifts in distribution relative to reference points were in the same direction ( richer, softer soil). Furthermore, of 135 pairwise comparisons among the species, only 7 were significantly different. More than three-fourths of all seedlings (75.3%) survived over the 2-year monitoring period, but survival rates varied widely among species. In no case was the probability of survival influenced by any microhabitat parameter. Relative height growth rates for the seedlings over 2 years varied from – 0.031 cm cm(-1) year(-1) (Dicorynia guianensis, Caesalpiniaceae) to 0.088 cm cm(-1) year(-1) (Virola michelii, Myristicaceae). In only 4 of 30 cases was height growth significantly associated with one of the three principal components. Because the conditions in this study were designed to maximize the chance of finding microhabitat differentiation among a group of species differing greatly in life history traits, the lack of microhabitat specialization it uncovered suggests that microhabitat partitioning among tropical tree species at the established seedling stage is unlikely to contribute greatly to coexistence among these species. | ||||
| Address | INRA Kourou, UMR Ecol Forets Guyane, Kourou 97387, French Guiana, Email: baraloto.c@kourou.cirad.fr | ||||
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| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0029-8549 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | ISI:000224999800015 | Approved | no | ||
| Call Number | EcoFoG @ eric.marcon @ | Serial | 233 | ||
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| Author | Orivel, J.; Lambs, L.; Male, P.J.G.; Leroy, C.; Grangier, J.; Otto, T.; Quilichini, A.; Dejean, A. | ||||
| Title | Dynamics of the association between a long-lived understory myrmecophyte and its specific associated ants | Type | Journal Article | ||
| Year | 2011 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 165 | Issue | 2 | Pages | 369-376 |
| Keywords | Allomerus decemarticulatus; Hirtella physophora; Lifespan; Mutualism; Myrmecophyte | ||||
| Abstract | Myrmecophytic symbioses are widespread in tropical ecosystems and their diversity makes them useful tools for understanding the origin and evolution of mutualisms. Obligate ant-plants, or myrmecophytes, provide a nesting place, and, often, food to a limited number of plant-ant species. In exchange, plant-ants protect their host plants from herbivores, competitors and pathogens, and can provide them with nutrients. Although most studies to date have highlighted a similar global pattern of interactions in these systems, little is known about the temporal structuring and dynamics of most of these associations. In this study we focused on the association between the understory myrmecophyte Hirtella physophora (Chrysobalanaceae) and its obligate ant partner Allomerus decemarticulatus (Myrmicinae). An examination of the life histories and growth rates of both partners demonstrated that this plant species has a much longer lifespan (up to about 350 years) than its associated ant colonies (up to about 21 years). The size of the ant colonies and their reproductive success were strongly limited by the available nesting space provided by the host plants. Moreover, the resident ants positively affected the vegetative growth of their host plant, but had a negative effect on its reproduction by reducing the number of flowers and fruits by more than 50%. Altogether our results are important to understanding the evolutionary dynamics of ant-plant symbioses. The highly specialized interaction between long-lived plants and ants with a shorter lifespan produces an asymmetry in the evolutionary rates of the interaction which, in return, can affect the degree to which the interests of the two partners converge. | ||||
| Address | [Orivel, Jerome; Leroy, Celine; Quilichini, Angelique; Dejean, Alain] CNRS, UMR Ecol Forets Guyane, F-97379 Kourou, France, Email: jerome.orivel@ecofog.gf | ||||
| Corporate Author | Thesis | ||||
| Publisher | Springer | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0029-8549 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | ISI:000286224900012 | Approved | no | ||
| Call Number | EcoFoG @ webmaster @ | Serial | 295 | ||
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| Author | Barantal, S.; Roy, J.; Fromin, N.; Schimann, H.; Hattenschwiler, S. | ||||
| Title | Long-term presence of tree species but not chemical diversity affect litter mixture effects on decomposition in a neotropical rainforest | Type | Journal Article | ||
| Year | 2011 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 167 | Issue | 1 | Pages | 241-252 |
| Keywords | Amazonian rainforest; Chemical diversity; Decomposition; Functional diversity indices; Litter traits | ||||
| Abstract | Plant litter diversity effects on decomposition rates are frequently reported, but with a strong bias towards temperate ecosystems. Altered decomposition and nutrient recycling with changing litter diversity may be particularly important in tree species-rich tropical rainforests on nutrient-poor soils. Using 28 different mixtures of leaf litter from 16 Amazonian rainforest tree species, we tested the hypothesis that litter mixture effects on decomposition increase with increasing functional litter diversity. Litter mixtures and all single litter species were exposed in the field for 9 months using custom-made microcosms with soil fauna access. In order to test the hypothesis that the long-term presence of tree species contributing to the litter mixtures increases mixture effects on decomposition, microcosms were installed in a plantation at sites including the respective tree species composition and in a nearby natural forest where these tree species are absent. We found that mixture decomposition deviated from predictions based on single species, with predominantly synergistic effects. Functional litter diversity, defined as either richness, evenness, or divergence based on a wide range of chemical traits, did not explain the observed litter mixture effects. However, synergistic effects in litter mixtures increased with the long-term presence of tree species contributing to these mixtures as the home field advantage hypothesis assumes. Our data suggest that complementarity effects on mixed litter decomposition may emerge through long-term interactions between aboveground and belowground biota. | ||||
| Address | [Barantal, S; Roy, J; Fromin, N; Hattenschwiler, S] CEFE CNRS, UMR 5175, F-34293 Montpellier 5, France, Email: sandra.barantal@cefe.cnrs.fr | ||||
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| Publisher | Springer | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0029-8549 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | WOS:000293914000024 | Approved | no | ||
| Call Number | EcoFoG @ webmaster @ | Serial | 336 | ||
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| Author | Stahl, C.; Herault, B.; Rossi, V.; Burban, B.; Bréchet, C.; Bonal, D. | ||||
| Title | Depth of soil water uptake by tropical rainforest trees during dry periods: Does tree dimension matter? | Type | Journal Article | ||
| Year | 2013 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 173 | Issue | 4 | Pages | 1191-1201 |
| Keywords | Deuterium; Oxygen; Root; Soil water; Tropical rainforest | ||||
| Abstract | Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψpd) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψpd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models. © 2013 Springer-Verlag Berlin Heidelberg. | ||||
| Address | INRA, UMR EEF 1137, 54280 Champenoux, France | ||||
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| ISSN | 00298549 (Issn) | ISBN | Medium | ||
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| Notes | Export Date: 6 December 2013; Source: Scopus; Coden: Oecob; doi: 10.1007/s00442-013-2724-6; Language of Original Document: English; Correspondence Address: Bonal, D.; INRA, UMR EEF 1137, 54280 Champenoux, France; email: bonal@nancy.inra.fr; References: Améglio, T., Archer, P., Cohen, M., Valancogne, C., Daudet, F.A., Dayau, S., Cruiziat, P., Significance and limits in the use of predawn leaf water potential for tree irrigation (1999) Plant Soil, 207, pp. 155-167; Baraloto, C., Morneau, F., Bonal, D., Blanc, L., Ferry, B., Seasonal water stress tolerance and habitat associations within four Neotropical tree genera (2007) Ecology, 88, pp. 478-489; Bonal, D., Barigah, T.S., Granier, A., Guehl, J.-M., Late-stage canopy tree species with extremely low delta C-13 and high stomatal sensitivity to seasonal soil drought in the tropical rainforest of French Guiana (2000) Plant Cell Environ, 23, pp. 445-459; Bonal, D., Atger, C., Barigah, T.S., Ferhi, A., Guehl, J.-M., Ferry, B., Water acquisition patterns of two wet tropical canopy tree species of French Guiana as inferred from H218O extraction profiles (2000) Ann For Sci, 57, pp. 717-724; Bonal, D., Bosc, A., Ponton, S., Goret, J.-Y., Burban, B., Gross, P., Bonnefond, J.-M., Granier, A., Impact of severe dry season on net ecosystem exchange in the Neotropical rainforest of French Guiana (2008) Glob Chang Biol, 14, pp. 1917-1933; Cao, K.F., Water relations and gas exchange of tropical saplings during a prolonged drought in a Bornean heath forest, with reference to root architecture (2000) J Trop Ecol, 16, pp. 101-116; Carvalheiro, K.O., Nepstad, D.C., Deep soil heterogeneity and fine root distribution in forests and pastures of eastern Amazonia (1996) Plant Soil, 182, pp. 279-285; Chmura, D.J., Anderson, P.D., Howe, G.T., Harrington, C.A., Halofsky, J.E., Peterson, D.L., Shaw, D.C., Brad St Claire, J., Forest responses to climate change in the northwestern United States: ecophysiological foundations for adaptive management (2011) For Ecol Manage, 261, pp. 1121-1142; da Rocha, H.R., Goulden, M.L., Miller, S.D., Menton, M.C., Pinto, L.D.V.O., de Freitas, H.C., e Silva Figueira, A.M., Seasonality of water and heat fluxes over a tropical forest in eastern Amazonia (2004) Ecol Appl, 14, pp. 22-32; Davidson, E., Lefebvre, P.A., Brando, P.M., Ray, D.M., Trumbore, S.E., Solorzano, L.A., Ferreira, J.N., Nepstad, D.C., Carbon inputs and water uptake in deep soils of an eastern Amazon forest (2011) For Sci, 57, pp. 51-58; Engelbrecht, B.M.J., Kursar, T.A., Comparative drought-resistance of seedlings of 28 species of co-occurring tropical woody plants (2003) Oecologia, 136, pp. 383-393; Engelbrecht, B.M.J., Wright, S.J., De Steven, D., Survival and ecophysiology of tree seedlings during El Nino drought in a tropical moist forest in Panama (2002) J Trop Ecol, 18, pp. 569-579; Fisher, R.A., Williams, M., Do Vale, R.L., Da Costa, A.L., Meir, P., Evidence from Amazonian forests is consistent with isohydric control of leaf water potential (2006) Plant Cell Environ, 29, pp. 151-165; Goulden, M.L., Miller, S.D., da Rocha, H.R., Menton, M.C., De Freitas, H.C., Silva Figueira, A.M.E., De Sousa, C.A.D., Diel and seasonal patterns of tropical forest CO2 exchange (2004) Ecol Appl, 14, pp. 42-54; Gourlet-Fleury, S., Ferry, B., Molino, J.F., Petronelli, P., Schmitt, L., Experimental plots: key features (2004) Ecology and management of a Neotropical Rainforest, pp. 3-60. , In: Gourlet-Fleury S, Guehl JM, Laroussinie O (eds) Lessons drawn from Paracou, a long-term experimental research site in French Guiana. 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Malhi, Y., Wright, J., Spatial patterns and recent trends in the climate of tropical rainforest regions (2004) Phil Trans R Soc Lond B, 359, pp. 311-329; Markewitz, D., Devine, S., Davidson, E.A., Brando, P., Nepstad, D.C., Soil moisture depletion under simulated drought in the Amazon: impacts on deep root uptake (2010) New Phytol, 187, pp. 592-607; Meinzer, F.C., Andrade, J.L., Goldstein, G., Holbrook, N.M., Cavelier, J., Wright, S.J., Partitioning of soil water among trees in a seasonally dry tropical forest (1999) Oecologia, 121, pp. 293-301; Merbold, L., Ardo, J., Arneth, A., Scholes, R.J., Nouvellon, Y., de Grandcourt, A., Archibald, S., Kutsch, W.L., Precipitation as driver of carbon fluxes in 11 African ecosystems (2009) Biogeosciences, 6, pp. 1027-1041; Moreira, M., Sternberg, L., Nepstad, D., Vertical patterns of soil water uptake by plants in a primary forest and an abandoned pasture in the eastern Amazon: an isotopic approach (2000) Plant Soil, 222, pp. 95-107; Nepstad, D.C., De Carvalho, C.R., Davidson, E.A., Jipp, P.H., Lefebvre, P.A., Negreiros, G.H., Da Silva, E.D., Vieira, S., The role of deep roots in the hydrological and carbon cycles of Amazonian forests and pastures (1994) Nature, 372, pp. 666-669; Oliveira, R., Dawson, T., Burgess, S., Nepstad, D., Hydraulic redistribution in three Amazonian trees (2005) Oecologia, 145, pp. 354-363; Poorter, L., Markesteijn, L., Seedling traits determine drought tolerance of tropical tree species (2008) Biotropica, 40, pp. 321-331; (2010) R: A Language and Environment for Statistical Computing, , R Development Core Team, Vienna: R Foundation for Statistical Computing; Romero-Saltos, H., LdSL, S., Moreira, M.Z., Nepstad, D.C., Rainfall exclusion in an eastern Amazonian forest alters soil water movement and depth of water uptake (2005) Am J Bot, 92, pp. 443-455; Sobrado, M.A., Embolism vulnerability in drought-deciduous and evergreen species of a tropical dry forest (1997) Acta Oecol, 18, pp. 383-391; Stahl, C., Burban, B., Bompy, F., Jolin, Z.B., Sermage, J., Bonal, D., Seasonal variation in atmospheric relative humidity contributes to explaining seasonal variation in trunk circumference of tropical rain-forest trees in French Guiana (2010) J Trop Ecol, 26, pp. 393-405; 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Wang, G., Alo, C., Mei, R., Sun, S., Droughts, hydraulic redistribution, and their impact on vegetation composition in the Amazon forest (2011) Plant Ecol, 212, pp. 663-673; Williams, M., Malhi, Y., Nobre, A.D., Rastetter, E.B., Grace, J., Pereira, M.G.P., Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rainforest: a modelling analysis (1998) Plant Cell Environ, 21, pp. 953-968; Yavitt, J.B., Wright, S.J., Drought and irrigation effects on fine root dynamics in a tropical moist forest, Panama (2001) Biotropica, 33, pp. 421-434; Zapater, M., Hossann, C., Bréda, N., Bréchet, C., Bonal, D., Granier, A., Evidence of hydraulic lift in a young beech and oak mixed forest using 18O soil water labelling (2011) Trees Struct Funct, 25, pp. 885-894; Zhang, Y., Tan, Z., Song, Q., Yu, G., Sun, X., Respiration controls the unexpected seasonal pattern of carbon flux in an Asian tropical rain forest (2010) Atmos Environ, 44, pp. 3886-3893 | Approved | no | ||
| Call Number | EcoFoG @ webmaster @ | Serial | 514 | ||
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| Author | Salas-Lopez, A.; Mickal, H.; Menzel, F.; Orivel, J. | ||||
| Title | Ant-mediated ecosystem processes are driven by trophic community structure but mainly by the environment | Type | Journal Article | ||
| Year | 2017 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 183 | Issue | 1 | Pages | 249-261 |
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| Abstract | The diversity and functional identity of organisms are known to be relevant to the maintenance of ecosystem processes but can be variable in different environments. Particularly, it is uncertain whether ecosystem processes are driven by complementary effects or by dominant groups of species. We investigated how community structure (i.e., the diversity and relative abundance of biological entities) explains the community-level contribution of Neotropical ant communities to different ecosystem processes in different environments. Ants were attracted with food resources representing six ant-mediated ecosystem processes in four environments: ground and vegetation strata in cropland and forest habitats. The exploitation frequencies of the baits were used to calculate the taxonomic and trophic structures of ant communities and their contribution to ecosystem processes considered individually or in combination (i.e., multifunctionality). We then investigated whether community structure variables could predict ecosystem processes and whether such relationships were affected by the environment. We found that forests presented a greater biodiversity and trophic complementarity and lower dominance than croplands, but this did not affect ecosystem processes. In contrast, trophic complementarity was greater on the ground than on vegetation and was followed by greater resource exploitation levels. Although ant participation in ecosystem processes can be predicted by means of trophic-based indices, we found that variations in community structure and performance in ecosystem processes were best explained by environment. We conclude that determining the extent to which the dominance and complementarity of communities affect ecosystem processes in different environments requires a better understanding of resource availability to different species. | ||||
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| ISSN | 1432-1939 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ Salas-Lopez2017 | Serial | 715 | ||
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| Author | Rodríguez Pérez, H.; Borrel, G.; Leroy, C.; Carrias, J.-F.; Corbara, B.; Srivastava, D.S.; Céréghino, R. | ||||
| Title | Simulated drought regimes reveal community resilience and hydrological thresholds for altered decomposition | Type | Journal Article | ||
| Year | 2018 | Publication |
Oecologia | Abbreviated Journal | |
| Volume | 187 | Issue | 1 | Pages | 267-279 |
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| Abstract | Future climate scenarios forecast a 10–50% decline in rainfall in Eastern Amazonia. Altered precipitation patterns may change important ecosystem functions like decomposition through either changes in physical and chemical processes or shifts in the activity and/or composition of species. We experimentally manipulated hydroperiods (length of wet:dry cycles) in a tank bromeliad ecosystem to examine impacts on leaf litter decomposition. Gross loss of litter mass over 112 days was greatest in continuously submersed litter, lowest in continuously dry litter, and intermediate over a range of hydroperiods ranging from eight cycles of 7 wet:7 dry days to one cycle of 56 wet:56 dry days. The resilience of litter mass loss to hydroperiod length is due to a shift from biologically assisted decomposition (mostly microbial) at short wet:dry hydroperiods to physicochemical release of dissolved organic matter at longer wet:dry hydroperiods. Biologically assisted decomposition was maximized at wet:dry hydroperiods falling within the range of ambient conditions (12–22 consecutive dry days) but then declined under prolonged wet:dry hydroperiods (28 and 56 dry days. Fungal:bacterial ratios showed a similar pattern as biologically assisted decomposition to hydroperiod length. Our results suggest that microbial communities confer functional resilience to altered hydroperiod in tank bromeliad ecosystems. We predict a substantial decrease in biological activity relevant to decomposition under climate scenarios that increase consecutive dry days by 1.6- to 3.2-fold in our study area, whereas decreased frequency of dry periods will tend to increase the physicochemical component of decomposition. | ||||
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| ISSN | 1432-1939 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ Rodríguez Pérez2018 | Serial | 850 | ||
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| Author | Fichaux, M.; Béchade, B.; Donald, J.; Weyna, A.; Delabie, J.H.C.; Murienne, J.; Baraloto, C.; Orivel, J. | ||||
| Title | Habitats shape taxonomic and functional composition of Neotropical ant assemblages | Type | Journal Article | ||
| Year | 2019 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 189 | Issue | 2 | Pages | 501-513 |
| Keywords | Formicidae; Functional diversity; Habitat filtering; Rainforest; Traits; Formicidae | ||||
| Abstract | Determining assembly rules of co-occurring species persists as a fundamental goal in community ecology. At local scales, the relative importance of environmental filtering vs. competitive exclusion remains a subject of debate. In this study, we assessed the relative importance of habitat filtering and competition in structuring understory ant communities in tropical forests of French Guiana. Leaf-litter ants were collected using pitfall and Winkler traps across swamp, slope and plateau forests near Saül, French Guiana. We used a combination of univariate and multivariate analyses to evaluate trait response of ants to habitat characteristics. Null model analyses were used to investigate the effects of habitat filtering and competitive interactions on community assembly at the scale of assemblages and sampling points, respectively. Swamp forests presented a much lower taxonomic and functional richness compared to slope and plateau forests. Furthermore, marked differences in taxonomic and functional composition were observed between swamp forests and slope or plateau forests. We found weak evidence for competitive exclusion based on null models. Nevertheless, the contrasting trait composition observed between habitats revealed differences in the ecological attributes of the species in the different forest habitats. Our analyses suggest that competitive interactions may not play an important role in structuring leaf-litter ant assemblages locally. Rather, habitats are responsible for driving both taxonomic and functional composition of ant communities. | ||||
| Address | International Center for Tropical Botany, Department of Biological Sciences, Florida International University, Miami, FL 33199, United States | ||||
| Corporate Author | Thesis | ||||
| Publisher | Springer Verlag | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 00298549 (Issn) | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 863 | ||
| Permanent link to this record | |||||
| Author | Grossiord, C.; Christoffersen, B.; Alonso-Rodríguez, A.M.; Anderson-Teixeira, K.; Asbjornsen, H.; Aparecido, L.M.T.; Carter Berry, Z.; Baraloto, C.; Bonal, D.; Borrego, I.; Burban, B.; Chambers, J.Q.; Christianson, D.S.; Detto, M.; Faybishenko, B.; Fontes, C.G.; Fortunel, C.; Gimenez, B.O.; Jardine, K.J.; Kueppers, L.; Miller, G.R.; Moore, G.W.; Negron-Juarez, R.; Stahl, C.; Swenson, N.G.; Trotsiuk, V.; Varadharajan, C.; Warren, J.M.; Wolfe, B.T.; Wei, L.; Wood, T.E.; Xu, C.; McDowell, N.G. | ||||
| Title | Precipitation mediates sap flux sensitivity to evaporative demand in the neotropics | Type | Journal Article | ||
| Year | 2019 | Publication |
Oecologia | Abbreviated Journal | Oecologia |
| Volume | 191 | Issue | 3 | Pages | 519-530 |
| Keywords | Evapotranspiration; Plant functional traits; Transpiration; Vapor pressure deficit; drought; evapotranspiration; flux measurement; hydrological cycle; Neotropical Region; precipitation (chemistry); precipitation (climatology); tree; tropical forest; tropical region; vapor pressure; water; drought; evapotranspiration; forest; tree; vapor pressure; Droughts; Forests; Plant Transpiration; Trees; Vapor Pressure; Water | ||||
| Abstract | Transpiration in humid tropical forests modulates the global water cycle and is a key driver of climate regulation. Yet, our understanding of how tropical trees regulate sap flux in response to climate variability remains elusive. With a progressively warming climate, atmospheric evaporative demand [i.e., vapor pressure deficit (VPD)] will be increasingly important for plant functioning, becoming the major control of plant water use in the twenty-first century. Using measurements in 34 tree species at seven sites across a precipitation gradient in the neotropics, we determined how the maximum sap flux velocity (vmax) and the VPD threshold at which vmax is reached (VPDmax) vary with precipitation regime [mean annual precipitation (MAP); seasonal drought intensity (PDRY)] and two functional traits related to foliar and wood economics spectra [leaf mass per area (LMA); wood specific gravity (WSG)]. We show that, even though vmax is highly variable within sites, it follows a negative trend in response to increasing MAP and PDRY across sites. LMA and WSG exerted little effect on vmax and VPDmax, suggesting that these widely used functional traits provide limited explanatory power of dynamic plant responses to environmental variation within hyper-diverse forests. This study demonstrates that long-term precipitation plays an important role in the sap flux response of humid tropical forests to VPD. Our findings suggest that under higher evaporative demand, trees growing in wetter environments in humid tropical regions may be subjected to reduced water exchange with the atmosphere relative to trees growing in drier climates. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. | ||||
| Address | Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, WA, United States | ||||
| Corporate Author | Thesis | ||||
| Publisher | Springer Verlag | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 00298549 (Issn) | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | EcoFoG @ webmaster @ | Serial | 904 | ||
| Permanent link to this record | |||||