Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2020
Authors
Eduardo Collado Carles Castano Jose Antonio Bonet Andreas Hagenbo Juan Martínez de Aragon Sergio de-MiguelAbstract
No abstract has been registered
Authors
Andreas Hagenbo Yasmine Piñuela Carles Castano Juan Martınez de Aragon Sergio de-Miguel Josu G. Alday Jose Antonio BonetAbstract
* In forests, ectomycorrhizal mycelium is pivotal for driving soil carbon and nutrient cycles, but how ectomycorrhizal mycelial dynamics vary in ecosystems with drought periods is unknown. We quantified the production and turnover of mycorrhizal mycelium in Mediterranean Pinus pinaster, Pinus sylvestris and Quercus ilex forests and related the estimates to standardised precipitation index (SPI), to study how mycelial dynamics relates to tree species and drought‐moisture conditions. * Production and turnover of mycelium was estimated between July and February, by quantifying the fungal biomass (ergosterol) in ingrowth mesh bags and using statistical modelling. SPI for time scales of 1–3 months was calculated from precipitation records and precipitation data over the study period. * Forests dominated by Pinus trees displayed higher biomass but were seasonally more variable, as opposed to Q. ilex forests where the mycelial biomass remained lower and stable over the season. Production and turnover, respectively, varied between 1.4–5.9 kg ha−1 d−1 and 7.2–9.9 times yr−1 over the different forest types and were positively correlated with 2‐month and 3‐month SPI over the study period. * Our results demonstrated that mycorrhizal mycelial biomass varied with season and tree species and we speculate that production and turnover are related to physiology and plant host performance during drought.
Abstract
When free-ranging animals encounter traffic on roads or railways, it may have fatal outcome. In Europe, collisions between vehicles and animals have increased the last 40 years, causing eco-nomic losses and serious welfare concerns. Today there is no technological solution to prevent such collisions in the rough, arctic climate that represents most parts of Norway. By using small and energy-efficient radio transmitters moulded into headcollars, researchers have now devel-oped and tested a system for warning traffic when semi-domestic reindeer are nearby the road. Tests on more than 700 reindeer over three consecutive winter seasons are promising.
Authors
Miren del Río Marta Vergarechea Torben Hilmers Josu G. Alday Admir Avdagić Franz Binderh Michal Bošeľa Laura Dobor David I. Forrester Velid Halilović Aida Ibrahimspahic Matija Klopcic Mathieu Lévesque Thomas A. Nagel Zuzana Sitková Gerhard Schütze Branko Stajic Dejan Stojanovic Enno Uhl Tzvetan Zlatanov Roberto Tognetti Hans PretzschAbstract
Spruce-fir-beech mixed forests cover a large area in European mountain regions, with high ecological and socio-economic importance. As elevation-zone systems they are highly affected by climate change, which is modifying species growth patterns and productivity shifts among species. The extent to which associated tree species can access resources and grow asynchronously may affect their resistance and persistence under climate change. Intra-specific synchrony in annual tree growth is a good indicator of species specific dependence on environmental conditions variability. However, little attention has been paid to explore the role of the inter-specific growth asynchrony in the adaptation of mixed forests to climate change. Here we used a database of 1790 tree-ring series collected from 28 experimental plots in spruce-fir-beech mixed forests across Europe to explore how spatio-temporal patterns of the intra- and inter-specific growth synchrony relate to climate variation during the past century. We further examined whether synchrony in growth response to inter-annual environmental fluctuations depended on site conditions. We found that the inter-specific growth synchrony was always lower than the intra-specific synchrony, for both high (inter-annual fluctuations) and low frequency (mid- to long-term) growth variation, suggesting between species niche complementarity at both temporal levels. Intra- and inter-specific synchronies in inter-annual growth fluctuations significantly changed along elevation, being greater at higher elevations. Moreover, the climate warming likely induced temporal changes in synchrony, but the effect varied along the elevation gradient. The synchrony strongly intensified at lower elevations likely due to climate warming and drying conditions. Our results suggest that intra- and inter-specific growth synchrony can be used as an indicator of temporal niche complementarity among species. We conclude that spruce-fir-beech mixtures should be preferred against mono-specific forests to buffer climate change impacts in mountain regions.
Abstract
Because of generally small log piles, loading forwarders during thinning is time consuming. The Assortment Grapple, an innovative grapple with an extra pair of claws which facilitates the handling of two assortments during one loading crane cycle, has been designed to decrease forwarders’ loading time consumption. A standardized experiment was performed in a virtual thinning stand using a machine simulator with the objectives to form guidelines for working with the Assortment Grapple and to analyse its development potential. Four experienced operators participated in the study. According to the results, the Assortment Grapple’s accumulating function is beneficial only when there are no remaining trees between piles loaded during the same crane cycle. In such cases, none of participating operators lost time, and 3 of 4 operators saved time notably. The problem with the remaining trees is the extra time required to steer the crane tip around them. Therefore, a harvester should place those log piles that are later to be forwarded together in the same space with no remaining trees between the piles. Furthermore, we recommend that the Assortment Grapple’s usability will be improved by adding an own rocker switch on the forwarder’s controls to command the extra claws.
Abstract
No abstract has been registered
Authors
Erik J. M. Koenen Dario Isidro Ojeda Alayon Royce Steeves Jérémy Migliore Freek T. Bakker Jan J. Wieringa Catherine Kidner Olivier J. Hardy R. Toby Pennington Anne Bruneau Colin E. HughesAbstract
Phylogenomics is increasingly used to infer deep‐branching relationships while revealing the complexity of evolutionary processes such as incomplete lineage sorting, hybridization/introgression and polyploidization. We investigate the deep‐branching relationships among subfamilies of the Leguminosae (or Fabaceae), the third largest angiosperm family. Despite their ecological and economic importance, a robust phylogenetic framework for legumes based on genome‐scale sequence data is lacking. We generated alignments of 72 chloroplast genes and 7621 homologous nuclear‐encoded proteins, for 157 and 76 taxa, respectively. We analysed these with maximum likelihood, Bayesian inference, and a multispecies coalescent summary method, and evaluated support for alternative topologies across gene trees. We resolve the deepest divergences in the legume phylogeny despite lack of phylogenetic signal across all chloroplast genes and the majority of nuclear genes. Strongly supported conflict in the remainder of nuclear genes is suggestive of incomplete lineage sorting. All six subfamilies originated nearly simultaneously, suggesting that the prevailing view of some subfamilies as ‘basal’ or ‘early‐diverging’ with respect to others should be abandoned, which has important implications for understanding the evolution of legume diversity and traits. Our study highlights the limits of phylogenetic resolution in relation to rapid successive speciation.
Authors
Boris B. Demenou Jérémy Migliore Myriam Heuertz Franck K. Monthe Dario Isidro Ojeda Alayon Jan J. Wieringa Gilles Dauby Laura Albreht Arthur Boom Olivier J. HardyAbstract
Paleo-environmental data show that the distribution of African rain forests was affected by Quaternary climate changes. In particular, the Dahomey Gap (DG) – a 200 km wide savanna corridor currently separating the West African and Central African rain forest blocks and containing relict rain forest fragments – was forested during the mid-Holocene and possibly during previous interglacial periods, whereas it was dominated by open vegetation (savanna) during glacial periods. Genetic signatures of past population fragmentation and demographic changes have been found in some African forest plant species using nuclear markers, but such events appear not to have been synchronous or shared across species. To better understand the colonization history of the DG by rain forest trees through seed dispersal, the plastid genomes of two widespread African forest legume trees, Anthonotha macrophylla and Distemonanthus benthamianus, were sequenced in 47 individuals for each species, providing unprecedented phylogenetic resolution of their maternal lineages (857 and 115 SNPs, respectively). Both species exhibit distinct lineages separating three regions: 1. Upper Guinea (UG, i.e. the West African forest block), 2. the area ranging from the DG to the Cameroon volcanic line (CVL), and 3. Lower Guinea (LG, the western part of the Central African forest block) where three lineages co-occur. In both species, the DG populations (including southern Nigeria west of Cross River) exhibit much lower genetic diversity than UG and LG populations, and their plastid lineages originate from the CVL, confirming the role of the CVL as an ancient forest refuge. Despite the similar phylogeographic structures displayed by A. macrophylla and D. benthamianus, molecular dating indicates very contrasting ages of lineage divergence (UG diverged from LG since c. 7 Ma and 0.7 Ma, respectively) and DG colonization (probably following the Mid Pleistocene Transition and the Last Glacial Maximum, respectively). The stability of forest refuge areas and repeated similar forest shrinking/expanding events during successive glacial periods might explain why similar phylogeographic patterns can be generated over contrasting timescales.
Authors
Manuel de la Estrella Sandra Cervantes Steven B. Janssens Félix Forest Olivier J. Hardy Dario Isidro Ojeda AlayonAbstract
Aim: The Guineo‐Congolian region in Africa constitutes the second largest area of tropical rainforest (TRF) in the world. It covered an estimated 15–22 million km2 during the late Miocene (55–11 Ma) and it has experienced since a declining trend, currently reaching 3.4 million km2, associated with increasing aridification and the replacement of TRF by savanna habitats. Here, we examine whether rainforest area contraction led to a decrease in net diversification rates linked to increasing extinction, or if it is associated with increasing opportunities for allopatric or ecological speciation during periods of forest fragmentation. Location: Tropical Africa, Guineo‐Congolian region. Taxon: Anthonotha, Englerodendron, Berlinia clade (Leguminosae). Methods: We used a target enrichment approach combined with a complete data set representing all genera within the Berlinia clade. We combined phylogenomic, dating estimates, habitat reconstruction and diversification rate analyses to infer the effect of change in rainforest area coverage at two taxonomic levels: among genera, and within Anthonotha and Englerodendron. Results: We recovered fully resolved and well‐supported relationships among all genera and among species within the two genera. Most genera (87.5%) diverged before the Pleistocene, but Anthonotha and Englerodendron diversified recently, during the most recent cycles of forest contraction and expansion of the Pleistocene. Main conclusions: Our results suggest that the Berlinia clade displays an overall trend of accumulation of species over evolutionary time, suggesting the reduction in TRF area has not decreased net diversification rates. Most habitat shifts to savanna occurred in the Miocene, with no major habitat shifts during the most recent phases of forest expansion–contraction in the Pleistocene. Shifts in habitat from lowland forest to savanna did not trigger diversification rates, but habitat fragmentation might have increased diversification rates through allopatric speciation.
Authors
Erik J. M. Koenen Dario Isidro Ojeda Alayon Freek T. Bakker Jan J. Wieringa Catherine Kidner Olivier J. Hardy R. Toby Pennington Patrick S. Herendeen Anne Bruneau Colin E. HughesAbstract
The consequences of the Cretaceous–Paleogene (K–Pg) boundary (KPB) mass extinction for the evolution of plant diversity remain poorly understood, even though evolutionary turnover of plant lineages at the KPB is central to understanding assembly of the Cenozoic biota. The apparent concentration of whole genome duplication (WGD) events around the KPB may have played a role in survival and subsequent diversification of plant lineages. To gain new insights into the origins of Cenozoic biodiversity, we examine the origin and early evolution of the globally diverse legume family (Leguminosae or Fabaceae). Legumes are ecologically (co-)dominant across many vegetation types, and the fossil record suggests that they rose to such prominence after the KPB in parallel with several well-studied animal clades including Placentalia and Neoaves. Furthermore, multiple WGD events are hypothesized to have occurred early in legume evolution. Using a recently inferred phylogenomic framework, we investigate the placement of WGDs during early legume evolution using gene tree reconciliation methods, gene count data and phylogenetic supernetwork reconstruction. Using 20 fossil calibrations we estimate a revised timeline of legume evolution based on 36 nuclear genes selected as informative and evolving in an approximately clock-like fashion. To establish the timing of WGDs we also date duplication nodes in gene trees. Results suggest either a pan-legume WGD event on the stem lineage of the family, or an allopolyploid event involving (some of) the earliest lineages within the crown group, with additional nested WGDs subtending subfamilies Papilionoideae and Detarioideae. Gene tree reconciliation methods that do not account for allopolyploidy may be misleading in inferring an earlier WGD event at the time of divergence of the two parental lineages of the polyploid, suggesting that the allopolyploid scenario is more likely. We show that the crown age of the legumes dates to the Maastrichtian or early Paleocene and that, apart from the Detarioideae WGD, paleopolyploidy occurred close to the KPB. We conclude that the early evolution of the legumes followed a complex history, in which multiple auto- and/or allopolyploidy events coincided with rapid diversification and in association with the mass extinction event at the KPB, ultimately underpinning the evolutionary success of the Leguminosae in the Cenozoic. [Allopolyploidy; Cretaceous–Paleogene (K–Pg) boundary; Fabaceae, Leguminosae; paleopolyploidy; phylogenomics; whole genome duplication events]