Bonal, D., Burban, B., Stahl, C., Wagner, F., & Herault, B. (2016). The response of tropical rainforests to drought—lessons from recent research and future prospects. Annals of Forest Science, 73(1), 27–44.
Abstract: Key message: We review the recent findings on the influence of drought on tree mortality, growth or ecosystem functioning in tropical rainforests. Drought plays a major role in shaping tropical rainforests and the response mechanisms are highly diverse and complex. The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical rainforests on the three continents. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. Context: Tropical rainforest ecosystems are characterized by high annual rainfall. Nevertheless, rainfall regularly fluctuates during the year and seasonal soil droughts do occur. Over the past decades, a number of extreme droughts have hit tropical rainforests, not only in Amazonia but also in Asia and Africa. The influence of drought events on tree mortality and growth or on ecosystem functioning (carbon and water fluxes) in tropical rainforest ecosystems has been studied intensively, but the response mechanisms are complex. Aims: Herein, we review the recent findings related to the response of tropical forest ecosystems to seasonal and extreme droughts and the current knowledge about the future of these ecosystems. Results: This review emphasizes the progress made over recent years and the importance of the studies conducted under extreme drought conditions or in through-fall exclusion experiments in understanding the response of these ecosystems. It also points to the great diversity and complexity of the response of tropical rainforest ecosystems to drought. Conclusion: The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical forest regions. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. © 2015, INRA and Springer-Verlag France.
Keywords: Carbon; Climate; Drought; Global change; Growth; Mortality; Soil; Tropical; Water
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Thibaut, B., Denaud, L., Collet, R., Marchal, R., Beauchene, J., Mothe, F., et al. (2016). Wood machining with a focus on French research in the last 50 years. Annals of Forest Science, 73(1), 163–184.
Abstract: Key message: Wood machining is compulsory both for timber separation and the surfacing of wooden objects. The anisotropy, cellular nature and multi-scale level organisation of wood make its cutting complicated to study. During the last 50 years, most of the wood machining subjects were covered by French teams. Context: Woodcutting is a very old technology but scientific research is scarce on the subject. In the last 50 years, much work on basic mechanisms as well as on industrial processes has been done in France. Aims: The specific nature of wood introduces strong differences between wood and metal cutting processes. The paper focuses on French teams’ contributions. Results: The basic aspects of the tool–material interaction for different basic modes in woodcutting are highlighted. In primary conversion such as sawing, veneer cutting or green wood chipping, huge progress comes from automation and the possibility of linking the process to log and product quality through new sensors. In secondary processing, much has been done on the links between the cutting process, surface qualification and the properties of these surfaces for further processing, such as gluing or coating. Tool wear depends on the cutting process, timber quality and species. Trade-offs are required in tool technology and coating technologies may improve tool life. Conclusion: A large amount of knowledge and innovation has come from 50 years of worldwide research effort, with France being particularly active in this period. The transfer of skills from metals cutting industry was often a key, but much is needed to move closer to both metal cutting sector and woodcutting skills among craftsmen. © 2015, INRA and Springer-Verlag France.
Keywords: Primary conversion; Secondary processing; Surface quality; Tool wear
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Scotti, I., González-Martínez, S. C., Budde, K. B., & Lalague, H. (2016). Fifty years of genetic studies: what to make of the large amounts of variation found within populations? Annals of Forest Science, 73(1), 69–75.
Keywords: Intra-specific variation; Microgeography; Natural selection; Population genomics
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Rossi, V., Dolley, T., Cornu, G., Guitet, S., & Herault, B. (2015). GuyaSim : un outil d’aide à la décision pour l’aménagement d’un territoire forestier, la Guyane. Bois et Forets des Tropiques, 326(4), 67–78.
Abstract: Planning policies for rapid development in French Guiana will require the conversion of forested areas, thus contributing to glo- bal warming. Guiana’s policy-makers will need to integrate the preservation of eco- system services into their planning deci- sions. The GuyaSim project was conduc- ted to produce more in-depth knowledge on these services (carbon sequestration, biodiversity and soil quality) and to trans- fer a software application, GuyaSim, to policy-makers to facilitate the use of this knowledge in the development of plan- ning policies. This article presents the characteristics of the application. Guya- Sim is a freeware package of the GIS type designed initially for local authority plan- ners and forestry departments in French Guiana. The application has two main functions:
information delivery and sup-
port for planning decisions. The informa- tion provided includes socio-economic development scenarios, climate scenarios and valuations of ecosystem services. The decision-support component consists of tools for building planning scenarios (land use changes) and forestry scenarios (log- ging), with information on their environ- mental impacts. The functionalities of the software are currently limited by the state of knowledge on Guiana’s ecosystems. Advances made through current research projects are expected to upgrade the application in the medium term.
Keywords: GIS software; scenarios; ecosystem services; simulator; biodiversity; carbon stock; biomass; logging; deforestation; land use changes; tropical forest; French Guiana
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ter Steege, H., Pitman, N. C. A., Killeen, T. J., Laurance, W. F., Peres, C. A., Guevara, J. E., et al. (2015). Estimating the global conservation status of more than 15,000 Amazonian tree species. Science Advances, 1(10).
Abstract: Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.
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Houadria, M., Blüthgen, N., Salas-Lopez, A., Schmitt, M. - I., Arndt, J., Schneider, E., et al. (2016). The relation between circadian asynchrony, functional redundancy, and trophic performance in tropical ant communities. Ecology, 97(1), 225–235.
Abstract: The diversity-stability relationship has been under intense scrutiny for the past decades, and temporal asynchrony is recognized as an important aspect of ecosystem stability. In contrast to relatively well- studied interannual and seasonal asynchrony, few studies investigate the role of circadian cycles for ecosystem stability. Here, we studied multifunctional redundancy of diurnal and nocturnal ant communities in four tropical rain forest sites. We analyzed how it was influenced by species richness, functional performance, and circadian asynchrony. In two neotropical sites, species richness and functional redundancy were lower at night. In contrast, these parameters did not differ in the two paleotropical sites we studied. Circadian asynchrony between species was pronounced in the neotropical sites, and increased circadian functional redundancy. In general, species richness positively affected functional redundancy, but the effect size depended on the temporal and spatial breadth of the species with highest functional performance. Our analysis shows that high levels of trophic performance were only reached through the presence of such high- performing species, but not by even contributions of multiple, less- efficient species. Thus, these species can increase current functional performance, but reduce overall functional redundancy. Our study highlights that diurnal and nocturnal ecosystem properties of the very same habitat can markedly differ in terms of species richness and functional redundancy. Consequently, like the need to study multiple ecosystem functions, multiple periods of the circadian cycle need to be assessed in order to fully understand the diversity- stability relationship in an ecosystem. © 2016 by the Ecological Society of America.
Keywords: Diel turnover; Ecosystem functioning; Functional diversity; Multifunctional redundancy; Sampling effect; Temporal partitioning; Tropical rain forests
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Zinger, L., Chave, J., Coissac, E., Iribar, A., Louisanna, E., Manzi, S., et al. (2016). Extracellular DNA extraction is a fast, cheap and reliable alternative for multi-taxa surveys based on soil DNA. Soil Biology and Biochemistry, 96, 16–19.
Abstract: DNA metabarcoding on soil samples is increasingly used for large-scale and multi-taxa biodiversity studies. However, DNA extraction may be a major bottleneck for such wide uses. It should be cost/time effective and allow dealing with large sample volumes so as to maximise the representativeness of both micro- and macro-organisms diversity. Here, we compared the performances of a fast and cheap extracellular DNA extraction protocol with a total DNA extraction method in retrieving bacterial, eukaryotic and plant diversity from tropical soil samples of ca. 10 g. The total DNA extraction protocol yielded more high-quality DNA. Yet, the extracellular DNA protocol provided similar diversity assessments although it presented some differences in clades relative abundance and undersampling biases. We argue that extracellular DNA is a good compromise between cost, labor, and accuracy for high-throughput DNA metabarcoding studies of soil biodiversity. © 2016 Elsevier Ltd.
Keywords: DNA extraction protocol; DNA metabarcoding; Multi-taxa biodiversity; Tropical forest
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Lamarre, G. P. A., Amoretti, D. S., Baraloto, C., Bénéluz, F., Mesones, I., & Fine, P. V. A. (2016). Phylogenetic Overdispersion in Lepidoptera Communities of Amazonian White-sand Forests. Biotropica, 48(1), 101–109.
Abstract: In the Amazon basin and the Guiana Shield, white-sand (WS) forests are recognized as a low-resource habitat often composed by a distinct flora with many edaphic endemic plants. Small patches of nutrient-poor white-sand forests can pose a series of challenges to plants and animals. For plants, these challenges have been shown to function as strong filters that in turn drive taxonomic, functional and phylogenetic plant composition. However, very little is known about animal communities in WS forest and the effect that low-resource availability may have on higher trophic levels. Here, we investigate the diversity of both taxonomic and phylogenetic diversity of three Lepidoptera families' (Nymphalidae, Saturniidae, and Sphingidae) assemblages between low-resource (White-Sand Forest) and two adjacent high-resource habitats, terra firme clay and seasonally flooded forests. We found no clear effect of habitat type on taxonomic composition although butterfly and moth species abundance differed among the three contrasted habitats. The WS forest Lepidoptera community is significantly more phylogenetically overdispersed than expected by chance. We suggest that these low-resource habitats filter the number of plant lineages which, in turn, creates a bottom-up control structuring Lepidoptera phylogenetic structure. We recommend long-term sampling on Lepidoptera community both at larval and adult stages that may complement this study and test hypotheses linking herbivore phylogenetic structure to plant resource availability and trophic cascade theory. © 2016 The Association for Tropical Biology and Conservation.
Keywords: varillales; Amazon basin; Bottom-up; Lepidoptera composition; Moth, Nymphalidae; Phylogenetic structure
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Guevara, J. E., Damasco, G., Baraloto, C., Fine, P. V. A., Peñuela, M. C., Castilho, C., et al. (2016). Low Phylogenetic Beta Diversity and Geographic Neo-endemism in Amazonian White-sand Forests. Biotropica, 48(1), 34–46.
Abstract: Over the past three decades, many small-scale floristic studies of white-sand forests across the Amazon basin have been published. Nonetheless, a basin-wide description of both taxonomic and phylogenetic alpha and beta diversity at regional scales has never been achieved. We present a complete floristic analysis of white-sand forests across the Amazon basin including both taxonomic and phylogenetic diversity. We found strong regional differences in the signal of phylogenetic community structure with both overall and regional Net Relatedness Index and Nearest Taxon Index values found to be significantly positive leading to a pattern of phylogenetic clustering. Additionally, we found high taxonomic dissimilarity but low phylogenetic dissimilarity in pairwise community comparisons. These results suggest that recent diversification has played an important role in the assembly of white-sand forests causing geographic neo-endemism patterns at the regional scale. © 2016 The Association for Tropical Biology and Conservation.
Keywords: Amazon; Neo-endemism; Phylogenetic beta diversity; Recent diversification; White sands
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Fine, P. V. A., & Baraloto, C. (2016). Habitat Endemism in White-sand Forests: Insights into the Mechanisms of Lineage Diversification and Community Assembly of the Neotropical Flora. Biotropica, 48(1), 24–33.
Abstract: White-sand forests represent natural laboratories of evolution over their long history throughout Amazonia and the Guiana Shield and pose significant physiological challenges to the plants and animals they host. The study of diversification in plant lineages comprising species endemic to white-sand forest can therefore give insights into processes of evolution and community assembly in tropical forests. In this article, we synthesize recent studies of white-sand forests to integrate patterns of plant species distribution with processes of lineage diversification and community assembly in the white-sand flora. We contrast lineages that have radiated uniquely in these habitats (e.g., Pagamea, Rubiaceae), with cosmopolitan lineages comprising specialists to white-sand forests and other habitats that may have arisen via ecological speciation across habitat gradients (e.g., Protium, Burseraceae). In both cases, similar suites of functional traits have evolved, including investment in dense, long-lived tissues that are well-defended structurally and chemically. White-sand endemics, therefore, play an important role in biodiversity conservation because they represent unique combinations of functional and phylogenetic diversity. Furthermore, white-sand endemics may respond differently than other tropical forest plant species to contemporary global changes because they comprise resilient functional types that may better withstand increased drought, temperature, and invasions of exotic pests in these regions. © 2016 The Association for Tropical Biology and Conservation.
Keywords: Amazon; Endemic; Functional traits; Habitat specialization; Niche conservatism; Speciation
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