Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Uncovering friction dynamics using hydrogel particles as soft ball bearings
    Rudge, Raisa E.D. ; De Sande, Jesse P.M. Van; Dijksman, Joshua A. ; Scholten, Elke - \ 2020
    Soft Matter 16 (2020)15. - ISSN 1744-683X - p. 3821 - 3831.

    Rolling ball bearings are widely known and applied to decrease friction between two surfaces. More recently, hydrogel-hydrogel tribopairs have also revealed good but rather complex lubrication properties. Here, we use hydrogels as ball bearings to elucidate that soft spherical particles have nontrivial rate-dependent lubrication behavior. Unlike Newtonian lubrication or dry solid friction, hydrogel particles in suspension transition through four frictional regimes as a function of sliding velocity. We relate the different regimes to the deformation of the particles at different gap sizes, which changes the effective contact area between the sliding surfaces. By systematically varying the particle characteristics and the surface properties of the sliding surfaces, we assign potential mechanisms for each of the different lubricating regimes as a function of velocity: (I) relatively high friction due to particle flattening and direct contact between interacting bodies (II) decrease of friction owing to the presence of rolling particles (III) large inflow of particles in a confined space leading to compressed particles and (IV) the formation of a thick lubricating layer. Using these suspensions with soft, deformable particles as a ball bearing system, we provide new insights into soft material friction with applications in emulsions, powders, pastes or other granular materials.

    Liana species decline in Congo basin contrasts with global patterns
    Bongers, Frans ; Ewango, Corneille E.N. ; Sande, Masha T. van der; Poorter, Lourens - \ 2020
    Ecology 101 (2020)5. - ISSN 0012-9658
    climbers - collapse - DR Congo - functional traits - Ituri - lianas - species abundance - tropical forest

    Lianas, woody climbing plants, are increasing in many tropical forests, with cascading effects such as decreased forest productivity, carbon sequestration, and resilience. Possible causes are increasing forest fragmentation, CO2 fertilization, and drought. Determining the primary changing species and their underlying vital rates help explain the liana trends. We monitored over 17,000 liana stems for 13 yr in 20 ha of old-growth forest in the Congo Basin, and here we report changes and vital rates for the community and for the 87 most abundant species. The total liana abundance declined from 15,007 lianas in 1994 to 11,090 in 2001 to 9,978 in 2007. Over half (52%) of the evaluated species have significantly declining populations, showing that the community response is not the result of changes in a few dominant species only. Species density change (i.e., the change in number of individuals per hectare) decreased with mortality rate, tended to increase with recruitment rate, but was independent of growth rate. Species change was independent of functional characteristics important for plant responses to fragmentation, CO2, and drought, such as lifetime light requirements, climbing and dispersal mechanism, and leaf size. These results indicate that in Congo lianas do not show the reputed global liana increase, but rather a decline, and that elements of the reputed drivers underlying global liana change do not apply to this DR Congo forest. We suggest warfare in the Congo Basin to have decimated the elephant population, leading to less disturbance, forest closure, and declining liana numbers. Our results imply that, in this tropical forest, local causes (i.e., disturbance) override more global causes of liana change resulting in liana decline, which sharply contrasts with the liana increase observed elsewhere.

    TRY plant trait database – enhanced coverage and open access
    Kattge, Jens ; Bönisch, Gerhard ; Díaz, Sandra ; Lavorel, Sandra ; Prentice, Iain Colin ; Leadley, Paul ; Tautenhahn, Susanne ; Werner, Gijsbert D.A. ; Aakala, Tuomas ; Abedi, Mehdi ; Acosta, Alicia T.R. ; Adamidis, George C. ; Adamson, Kairi ; Aiba, Masahiro ; Albert, Cécile H. ; Alcántara, Julio M. ; Alcázar C, Carolina ; Aleixo, Izabela ; Ali, Hamada ; Amiaud, Bernard ; Ammer, Christian ; Amoroso, Mariano M. ; Anand, Madhur ; Anderson, Carolyn ; Anten, Niels ; Antos, Joseph ; Apgaua, Deborah Mattos Guimarães ; Ashman, Tia Lynn ; Asmara, Degi Harja ; Asner, Gregory P. ; Aspinwall, Michael ; Atkin, Owen ; Aubin, Isabelle ; Baastrup-Spohr, Lars ; Bahalkeh, Khadijeh ; Bahn, Michael ; Bekker, Renee ; Cromsigt, Joris P.G.M. ; Finegan, Bryan ; Kramer, Koen ; Lohbeck, Madelon ; Onoda, Yusuke ; Ozinga, Wim A. ; Prinzing, Andreas ; Robroek, Bjorn ; Slot, Martijn ; Sterck, Frank ; Beest, Mariska te; Bodegom, Peter M. van; Sande, Masha T. van der - \ 2020
    Global Change Biology 26 (2020)1. - ISSN 1354-1013 - p. 119 - 188.
    data coverage - data integration - data representativeness - functional diversity - plant traits - TRY plant trait database

    Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

    Partitioning main carbon pools in a semi-deciduous rainforest in eastern Cameroon
    Zekeng, Jules Christian ; Sande, Masha T. van der; Fobane, Jean Louis ; Mphinyane, Wanda N. ; Sebego, Reuben ; Mbolo, Marguerite Marie Abada - \ 2020
    Forest Ecology and Management 457 (2020). - ISSN 0378-1127
    Biomass - Cameroon - Carbon storage - Climate change - Terra-firme semi-deciduous forest - Tropical rainforest - Variation partitioning

    Tropical forests contribute to climate change mitigation by absorbing carbon from the atmosphere and storing this in biomass and soil organic matter. However, there is still considerable uncertainty about the above- and belowground quantity and distribution of carbon stocks in African forests. Here, we evaluate how different carbon pools (aboveground live biomass, aboveground dead biomass, belowground biomass) contribute to total carbon stocks, and how different carbon components (e.g. large trees, understorey trees, coarse woody debris, roots, soil organic carbon etc.) contribute to carbon pools and total carbon stocks. We evaluated data of extensive inventories within 30 1-ha plots spanning the terra-firme semi-deciduous forest in eastern Cameroon. Hence, the plots were placed at a mean distance of 1 km from the nearest plot and we analyzed the data using variation partitioning, linear regressions and correlation tests. We found that the terra-firme semi-deciduous forests store 283.97 ± 51.42 Mg C ha−1. The aboveground biomass pool, with a carbon stock of 180.99 ± 25.8 Mg C ha−1, mostly explained variation in total carbon stocks (R2 = 0.79). From all aboveground biomass components, carbon in large trees was most strongly correlated with total carbon stocks. The second most important carbon pool was belowground carbon (on average 85.06 ± 16.86 Mg C ha−1; R2 = 0.78), mainly explained by coarse root carbon. Carbon in dead biomass had only a small contribution to total carbon stocks (R2 = 0.04). Hence, our results indicate that aboveground live biomass is a good predictor for variation in total carbon storage within this semi-deciduous terra-firme forest. However, aboveground live carbon and belowground carbon and their interactions explained most of the variation in total carbon stock, indicating that a whole-ecosystem approach is necessary for a full understanding of the carbon cycle.

    Similar factors underlie tree abundance in forests in native and alien ranges
    Sande, Masha T. van der; Bruelheide, Helge ; Dawson, Wayne ; Dengler, Jürgen ; Essl, Franz ; Field, Richard ; Haider, Sylvia ; Kleunen, Mark van; Kreft, Holger ; Pagel, Joern ; Pergl, Jan ; Purschke, Oliver ; Pyšek, Petr ; Weigelt, Patrick ; Winter, Marten ; Attorre, Fabio ; Aubin, Isabelle ; Bergmeier, Erwin ; Chytrý, Milan ; Dainese, Matteo ; Sanctis, Michele De; Fagundez, Jaime ; Golub, Valentin ; Guerin, Greg R. ; Gutiérrez, Alvaro G. ; Jandt, Ute ; Jansen, Florian ; Jiménez-Alfaro, Borja ; Kattge, Jens ; Kearsley, Elizabeth ; Klotz, Stefan ; Kramer, Koen ; Moretti, Marco ; Niinemets, Ülo ; Peet, Robert K. ; Penuelas, Josep ; Petřík, Petr ; Reich, Peter B. ; Sandel, Brody ; Schmidt, Marco ; Sibikova, Maria ; Violle, Cyrille ; Whitfeld, Timothy J.S. ; Wohlgemuth, Thomas ; Knight, Tiffany M. - \ 2020
    Global Ecology and Biogeography 29 (2020)2. - ISSN 1466-822X - p. 281 - 294.
    abundance - dissimilarity - forest - functional traits - global - plant invasion - trees

    Aim: Alien plant species can cause severe ecological and economic problems, and therefore attract a lot of research interest in biogeography and related fields. To identify potential future invasive species, we need to better understand the mechanisms underlying the abundances of invasive tree species in their new ranges, and whether these mechanisms differ between their native and alien ranges. Here, we test two hypotheses: that greater relative abundance is promoted by (a) functional difference from locally co-occurring trees, and (b) higher values than locally co-occurring trees for traits linked to competitive ability. Location: Global. Time period: Recent. Major taxa studied: Trees. Methods: We combined three global plant databases: sPlot vegetation-plot database, TRY plant trait database and Global Naturalized Alien Flora (GloNAF) database. We used a hierarchical Bayesian linear regression model to assess the factors associated with variation in local abundance, and how these relationships vary between native and alien ranges and depend on species’ traits. Results: In both ranges, species reach highest abundance if they are functionally similar to co-occurring species, yet are taller and have higher seed mass and wood density than co-occurring species. Main conclusions: Our results suggest that light limitation leads to strong environmental and biotic filtering, and that it is advantageous to be taller and have denser wood. The striking similarities in abundance between native and alien ranges imply that information from tree species’ native ranges can be used to predict in which habitats introduced species may become dominant.

    Current climate, isolation and history drive global patterns of tree phylogenetic endemism
    Sandel, Brody ; Weigelt, Patrick ; Kreft, Holger ; Keppel, Gunnar ; Sande, Masha T. van der; Levin, Sam ; Smith, Stephen ; Craven, Dylan ; Knight, Tiffany M. - \ 2020
    Global Ecology and Biogeography 29 (2020)1. - ISSN 1466-822X - p. 4 - 15.
    biogeography - climate stability - historical contingency - islands - isolation - phylogenetic endemism - trees

    Aim: We mapped global patterns of tree phylogenetic endemism (PE) to identify hotspots and test hypotheses about possible drivers. Specifically, we tested hypotheses related to current climate, geographical characteristics and historical conditions and assessed their relative importance in shaping PE patterns. Location: Global. Time period: We used the present distribution of trees, and predictors covering conditions from the mid-Miocene to present. Major taxa studied: All seed-bearing trees. Methods: We compiled distributions for 58,542 tree species across 463 regions worldwide, matched these to a recent phylogeny of seed plants and calculated PE for each region. We used a suite of predictor variables describing current climate (e.g., mean annual temperature), geographical characteristics (e.g., isolation) and historical conditions (e.g., tree cover at the Last Glacial Maximum) in a spatial regression model to explain variation in PE. Results: Tree PE was highest on islands, and was higher closer to the equator. All three groups of predictor variables contributed substantially to the PE pattern. Isolation and topographic heterogeneity promoted high PE, as did high current tree cover. Among mainland regions, temperature seasonality was strongly negatively related to PE, while mean annual temperature was positively related to PE on islands. Some relationships differed among the major floristic regions. For example, tree cover at the Last Glacial Maximum was a positive predictor of PE in the Palaeotropics, while tree cover at the Miocene was a negative predictor of PE in the Neotropics. Main conclusions: Globally, PE can be explained by a combination of geographical, historical and current factors. Some geographical variables appear to be key predictors of PE. However, the impact of historic and current climate variables differs considerably among the major floristic regions, reflecting their unique histories. Hence, the current distribution of trees is the result of globally relevant geographical drivers and regional climatic histories.

    Data from: Current climate, isolation and history drive global patterns of tree phylogenetic endemism
    Sandel, Brody ; Weigelt, Patrick ; Kreft, Holger ; Keppel, Gunnar ; Sande, Masha van der; Levin, Sam ; Smith, Stephen ; Craven, Dylan ; Knight, Tiffany M. - \ 2019
    Dryad
    trees - endemism - Biogeography - historical contingency - phylogenetic endemism - isolation - islands - current - species richness - climate stability
    Aim: We mapped global patterns of tree phylogenetic endemism (PE) to identify hotspots and test hypotheses about possible drivers. Specifically, we tested hypotheses related to current climate, geographical characteristics and historical conditions, and assessed their relative importance in shaping PE patterns. Location: Global. Time period: We used the present distribution of trees, and predictors covering conditions from the mid-Miocene to present. Major taxa studied: All seed-bearing trees. Methods: We compiled distributions for 58,542 tree species across 463 regions worldwide, matched these to a recent phylogeny of seed plants, and calculated PE for each region. We used a suite of predictor variables describing current climate (e.g. mean annual temperature), geographical characteristics (e.g. isolation) and historical conditions (e.g. tree cover at the last glacial maximum) in a spatial regression model to explain variation in PE. Results: Tree PE was highest on islands, and was higher closer to the equator. All three groups of predictor variables contributed substantially to the PE pattern. Isolation and topographic heterogeneity promoted high PE, as did high current tree cover. Among mainland regions, temperature seasonality was strongly negatively related to PE, while mean annual temperature was positively related to PE on islands. Some relationships differed among the major floristic regions. For example, tree cover at the last glacial maximum was a positive predictor of PE in the Paleotropics, while tree cover at the Miocene was a negative predictor of PE in the Neotropics. Main conclusions: Globally, PE can be explained by a combination of geographic, historical, and current factors. Some geographic variables appear to be key predictors of PE. However, the impact of historic and current climate variables differs considerably among the major floristic regions, reflecting their unique histories. Hence, the current distribution of trees is the result of globally relevant geographic drivers and regional climatic histories.
    Op naar precisielandbouw 2.0 : eindrapport PPS PL2.0 2015-2019 topsectorproject AF-14275
    Kempenaar, Corné ; Dijk, Chris van; Hermans, Geert ; Steele-Dun, Susan ; Sande, Corné van de; Verschoore, Jeroen ; Wal, Tamme van der; Roerink, Gerbert ; Visser, Juriaan ; Kamp, Jan ; Blok, Pieter ; Polder, Gerrit ; Wolf, Jan van de; Jalink, Henk ; Bulle, Annette ; Meurs, Bert ; Michielsen, Jean-Marie ; Zande, Jan van de; Hoving, Idse ; Riel, Johan van; Holshof, Gertjan ; Boheemen, Koen van; Evert, Frits van; Riemens, Marleen ; Keizer, Paul ; Schnabel, Sabine ; Egmond, Fenny van; Walvoort, Dennis ; Janssen, Henk ; Riviėre, Inge La; Kocks, Corné ; Pot, Alfred - \ 2019
    Lelystad : Stichting Wageningen Research, Wageningen University & Research (Rapport WPR 921) - 138
    De publiek private samenwerking (PPS) ‘Op naar precisielandbouw 2.0’ (PL2.0) is een R&D project van de topsector AgriFood. Het project is gestart in 2015 met doorlooptijd van 4 jaar. Voor u ligt het eindrapport. In deze PPS werkten ruim 20 private bedrijven en organisaties, publieke kennisinstellingen en overheden samen aan strategische onderwerpen binnen precisielandbouw. Het project omvatte 13 deelprojecten verdeeld over vijf specifieke R&D thema’s, te weten slim satellietbeeldengebruik, sensorontwikkeling (ziektedetectie), slimme integratie van technologieën in toepassingen, perceelkarakteristieken voor schatten van opbrengstpotentie en ondersteunende ICT, en een generiek thema communicatie en kennisverspreiding.Met betrekking tot het thema satellietbeeldengebruik is uitgezocht hoe optische satellietbeelden in combinatie met radarbeelden of beelden verkregen via drone-camera’s beter gebruikt kunnen worden om de variatie en status van de bovengrondse hoeveelheid biomassa van gewassen in kaart te brengen en opbrengsten te voorspellen. Op het gebied van ziektedetectie is door middel van sensor fusion en artificial intelligence de detectie van virus- en bacterieziekten in aardappelplanten verbeterd. En werd een prototype sensorsysteem voor veldonderzoek ontwikkeld. Door slimme integratie van data, adviesmodellen en mechanisatie zijn er enkele variabel-doseertoepassingen ontwikkeld en gevalideerd. Het gaat hier om variabel doseren van Stikstof en herbiciden binnen teelten d.m.v. taakkaarten. In het verlengde hiervan is ook een ontwerp geleverd en als prototype gevalideerd voor een innovatieve beddenspuit in bloembollenteelt. Op grond van perceelkarakteristieken en ondersteunende ICT zijn inzichten en tools voor het inschatten van opbrengst(potentie) geleverd en wordt een doorkijk gegeven naar software voor verbeterde rijpadenplanning en perceelinformatie. De inzet op communicatie en kennisdeling heeft ca. 100 publicaties en presentaties in 4 jaar tijd opgeleverd. Voor meer details over resultaten wordt naar de rapportage met samenvatting per deelproject verwezen in de hoofdstukken 2 tot en met 7.Het grote succes van PL2.0 ligt vooral bij ruime aandacht voor integratie van componenten van precisielandbouwtoepassingen en de doorstroming daarvan naar de praktijk en onderwijs.Geconcludeerd mag worden dat PL2.0 een bijdrage leverde aan gewasmonitoringtoepassingen en diverse variabel-doseertoepassingen (variable rate applications, VRA). Die VRA-toepassingen zien we nu op de agenda in het in 2018 gestarte precisielandbouw-adoptie project ‘Nationale Proeftuin Precisielandbouw’ (NPPL). Meerdere bedrijven passen taakkaarten variabel doseren op een resolutie van 30-50 m2 op praktijkschaal toe en besparen zo’n 20 -30% op gewasbeschermingsmiddelen met behoud van goede werking. De basis hiervoor is een bodem- of gewaskaart die de relevante variatie binnen de bodem of gewas in kaart brengt. Ook zijn er via PL2.0 mooie resultaten met optimalisatie van plantdichtheid en vermindering van meststoffengebruik via deze kaarten. Doorstroming van kennis naar het groene onderwijs werd gerealiseerd via PL2.0 en een versterkend WURKS-traject. Negen lesmodules over gebruik software en inzet taakkaarten in precisielandbouw werden opgeleverd. Precisielandbouw is geen doel op zich, maar een manier om de duurzaamheid van landbouw te vergroten. Met PL2.0 toepassingen kan meer met minder en beter geproduceerd worden. De trend van precisielandbouw c.q. data-gedreven landbouw of smart farming, zal zich alleen maar doorzetten. Er zal gewerkt gaan worden met meer en hoog-resolutie data, complexere adviesmodellen en meer robotisering. Daarmee zullen de doelen van kringlooplandbouw beter en sneller gerealiseerd kunnen worden.
    Practical implementation of real-time fish classification from acoustic broadband echo sounder data
    Berges, B. ; Sande, J. van de; Quesson, B. ; Sakinan, S. ; Helmond, E. van; Heijningen, A. van; Burgraaf, D. ; Fassler, S. - \ 2019
    IJmuiden : Wageningen Marine Research (Wageningen Marine Research report C076/19) - 150
    Wet and dry tropical forests show opposite successional pathways in wood density but converge over time
    Poorter, Lourens ; Rozendaal, Danaë M.A. ; Bongers, Frans ; Almeida-Cortez, Jarcilene S. de; Almeyda Zambrano, Angélica María ; Álvarez, Francisco S. ; Andrade, José Luís ; Villa, Luis Felipe Arreola ; Balvanera, Patricia ; Becknell, Justin M. ; Bentos, Tony V. ; Bhaskar, Radika ; Boukili, Vanessa ; Brancalion, Pedro H.S. ; Broadbent, Eben N. ; César, Ricardo G. ; Chave, Jerome ; Chazdon, Robin L. ; Colletta, Gabriel Dalla ; Craven, Dylan ; Jong, Ben H.J. de; Denslow, Julie S. ; Dent, Daisy H. ; DeWalt, Saara J. ; García, Elisa Díaz ; Dupuy, Juan Manuel ; Durán, Sandra M. ; Espírito Santo, Mário M. ; Fandiño, María C. ; Fernandes, Geraldo Wilson ; Finegan, Bryan ; Moser, Vanessa Granda ; Hall, Jefferson S. ; Hernández-Stefanoni, José Luis ; Jakovac, Catarina C. ; Junqueira, André B. ; Kennard, Deborah ; Lebrija-Trejos, Edwin ; Letcher, Susan G. ; Lohbeck, Madelon ; Lopez, Omar R. ; Marín-Spiotta, Erika ; Martínez-Ramos, Miguel ; Martins, Sebastião V. ; Massoca, Paulo E.S. ; Meave, Jorge A. ; Mesquita, Rita ; Mora, Francisco ; Souza Moreno, Vanessa de; Müller, Sandra C. ; Muñoz, Rodrigo ; Muscarella, Robert ; Oliveira Neto, Silvio Nolasco de; Nunes, Yule R.F. ; Ochoa-Gaona, Susana ; Paz, Horacio ; Peña-Claros, Marielos ; Piotto, Daniel ; Ruíz, Jorge ; Sanaphre-Villanueva, Lucía ; Sanchez-Azofeifa, Arturo ; Schwartz, Naomi B. ; Steininger, Marc K. ; Thomas, William Wayt ; Toledo, Marisol ; Uriarte, Maria ; Utrera, Luis P. ; Breugel, Michiel van; Sande, Masha T. van der; Wal, Hans van der; Veloso, Maria D.M. ; Vester, Hans F.M. ; Vieira, Ima C.G. ; Villa, Pedro Manuel ; Williamson, G.B. ; Wright, S.J. ; Zanini, Kátia J. ; Zimmerman, Jess K. ; Westoby, Mark - \ 2019
    Nature Ecology & Evolution 3 (2019). - ISSN 2397-334X - p. 928 - 934.

    Tropical forests are converted at an alarming rate for agricultural use and pastureland, but also regrow naturally through secondary succession. For successful forest restoration, it is essential to understand the mechanisms of secondary succession. These mechanisms may vary across forest types, but analyses across broad spatial scales are lacking. Here, we analyse forest recovery using 1,403 plots that differ in age since agricultural abandonment from 50 sites across the Neotropics. We analyse changes in community composition using species-specific stem wood density (WD), which is a key trait for plant growth, survival and forest carbon storage. In wet forest, succession proceeds from low towards high community WD (acquisitive towards conservative trait values), in line with standard successional theory. However, in dry forest, succession proceeds from high towards low community WD (conservative towards acquisitive trait values), probably because high WD reflects drought tolerance in harsh early successional environments. Dry season intensity drives WD recovery by influencing the start and trajectory of succession, resulting in convergence of the community WD over time as vegetation cover builds up. These ecological insights can be used to improve species selection for reforestation. Reforestation species selected to establish a first protective canopy layer should, among other criteria, ideally have a similar WD to the early successional communities that dominate under the prevailing macroclimatic conditions.

    The hydraulic efficiency-safety trade-off differs between lianas and trees
    Sande, Masha T. van der; Poorter, Lourens ; Schnitzer, Stefan A. ; Engelbrecht, Bettina M.J. ; Markesteijn, Lars - \ 2019
    Ecology 100 (2019)5. - ISSN 0012-9658
    Hydraulic traits are important for woody plant functioning and distribution. Associations among hydraulic traits, other leaf and stem traits, and species’ performance are relatively well understood for trees, but remain poorly studied for lianas. We evaluated the coordination among hydraulic efficiency (i.e. maximum hydraulic conductivity), hydraulic safety (i.e. cavitation resistance), a suite of 8 morphological and physiological traits, and species’ abundances for saplings of 24 liana species and 27 tree species in wet tropical forests in Panama. Trees showed a strong trade‐off between hydraulic efficiency and hydraulic safety, whereas efficiency and safety were decoupled in lianas. Hydraulic efficiency was strongly and similarly correlated with acquisitive traits for lianas and trees (e.g. positively with gas exchange rates and negatively with wood density). Hydraulic safety, however, showed no correlations with other traits in lianas, but with several in trees (e.g. positively with leaf dry matter content and wood density and negatively with gas exchange rates), indicating that in lianas hydraulic efficiency is an anchor trait because it is correlated with many other traits, while in trees both efficiency and safety are anchor traits. Traits related to shade‐tolerance (e.g. low specific leaf area and high wood density) were associated with high local tree sapling abundance, but not with liana abundance. Our results suggest that different, yet unknown mechanisms determine hydraulic safety and local‐scale abundance for lianas compared to trees. For trees, the trade‐off between efficiency and safety will provide less possibilities for ecological strategies. For lianas, however, the uncoupling of efficiency and safety could allow them to have high hydraulic efficiency, and hence high growth rates, without compromising resistance to cavitation under drought, thus allowing them to thrive and outperform trees under drier conditions.
    A 7000-year history of changing plant trait composition in an Amazonian landscape; the role of humans and climate
    Sande, M.T. van der; Gosling, W. ; Correa-Metrio, A. ; Prado-Junior, Jamir A. ; Poorter, L. ; Oliveira, R.S. ; Mazzei, Luca ; Bush, M.B. - \ 2019
    Ecology Letters 22 (2019)6. - ISSN 1461-023X - p. 925 - 935.
    Tropical forests are shifting in species and trait composition, but the main underlying causes remain unclear because of the short temporal scales of most studies. Here, we develop a novel approach by linking functional trait data with 7000 years of forest dynamics from a fossil pollen record of Lake Sauce in the Peruvian Amazon. We evaluate how climate and human disturbances affect community trait composition. We found weak relationships between environmental conditions and traits at the taxon level, but strong effects for community‐mean traits. Overall, community‐mean traits were more responsive to human disturbances than to climate change; human‐induced erosion increased the dominance of dense‐wooded, non‐zoochorous species with compound leaves, and human‐induced fire increased the dominance of tall, zoochorous taxa with large seeds and simple leaves. This information can help to enhance our understanding of forest responses to past environmental changes, and improve predictions of future changes in tropical forest composition.
    Data from: A 7000-year history of changing plant trait composition in an Amazonian landscape; the role of humans and climate
    Sande, M.T. van der; Gosling, W. ; Correa-Metrio, A. ; Prado-Junior, J. ; Poorter, L. ; Oliveira, R.S. ; Mazzei, L. ; Bush, M. - \ 2019
    Wageningen University & Research
    Amazon - charcoal - climate change - erosion - fire - fossil pollen - functional traits - human disturbance - Peru - tropical forest
    Tropical forests are shifting in species and trait composition, but the main underlying causes remain unclear because of the short temporal scales of most studies. Here, we develop a novel approach by linking functional trait data with 7000 years of forest dynamics from a fossil pollen record of Lake Sauce in the Peruvian Amazon. We evaluate how climate and human disturbances affect community trait composition. We found weak relationships between environmental conditions and traits at the taxon level, but strong effects for community-mean traits. Overall, community-mean traits were more responsive to human disturbances than to climate change; human-induced erosion increased the dominance of dense-wooded, non-zoochorous species with compound leaves, and human-induced fire increased the dominance of tall, zoochorous taxa with large seeds and simple leaves. This information can help to enhance our understanding of forest responses to past environmental changes, and improve predictions of future changes in tropical forest composition.
    Data from: The hydraulic efficiency–safety trade-off differs between lianas and trees
    Sande, M.T. van der; Poorter, L. ; Schnitzer, S.A. ; Engelbrecht, B.M.J. ; Markesteijn, L. - \ 2019
    Wageningen University & Research
    drought tolerance - functional traits - hydraulic conductivity - hydraulic architecture - plant-water relations - lianas - Panama - P50 - specia abundance - tropical forest
    Hydraulic traits are important for woody plant functioning and distribution. Associations among hydraulic traits, other leaf and stem traits, and species’ performance are relatively well understood for trees, but remain poorly studied for lianas. We evaluated the coordination among hydraulic efficiency (i.e. maximum hydraulic conductivity), hydraulic safety (i.e. cavitation resistance), a suite of 8 morphological and physiological traits, and species’ abundances for saplings of 24 liana species and 27 tree species in wet tropical forests in Panama.
    The unfulfilled promise of urban Lake Kleine Melanen (The Netherlands) : Diagnostics, experiment on reduction of sediment P-release and in-lake restoration
    Waajen, Guido ; Lürling, Miquel ; Sande, René van de - \ 2019
    Lake and Reservoir Management 35 (2019)1. - ISSN 1040-2381 - p. 8 - 24.
    Biomanipulation - cyanobacteria - eutrophication management - Phoslock - polyaluminumchloride - sediment capping - stormwater runoff

    Lake Kleine Melanen (The Netherlands) experienced cyanobacterial blooms during the summertime, causing public health risks, turbid water, and lack of macrophytes. To improve the situation, we determined the underlying causes of the poor water quality. Our diagnosis included the water and phosphorus (P) budget of the lake and showed the need for the reduction of both the external and internal P loads. The external P load (7.5 mg P/m2/d) exceeded the transition between the clear water state and the turbid state by 44–121%, mainly due to the discharges from the separated stormwater sewer system in the adjacent neighborhood. Due to political and financial considerations of the managing authorities, the restoration (2010–2012) was restricted to internal management. To reduce the high internal P load (3.8 mg P/m2/d), we tested 3 sediment capping options in an enclosure experiment, showing the best results when we combined sand capping with the P fixative Phoslock® and flocculant polyaluminumchloride. A 0.6–1.3 m thick layer of soft sediment was dredged from the lake. Thereafter, the sediment was capped with a 0.2 m thick layer of sand to which Phoslock® was added. Additional in-lake measures including fish removal and shoreline reconstruction were also conducted to support improvement. We compared water quality before (2008–2010) and after (2012–2014) interventions. Although the mean concentration of total P was reduced from 0.30 to 0.11 mg P/L, and cyanobacterial chlorophyll a from 52 to 6 μg/L, cyanobacterial blooms still occurred. For further water quality improvement, the reduction of the external P load caused by stormwater runoff is required.

    Data from: Disturbance intensity is a stronger driver of biomass recovery than remaining tree-community attributes in a managed Amazonian forest
    Avila, Angel L. de; Sande, M.T. van der; Dormann, C.F. ; Pena Claros, M. ; Poorter, L. ; Mazzei, Lucas ; Ruschel, Ademir Roberto ; Silva, José N.M. ; Carvalho, J.O.P. ; Bauhus, J. - \ 2018
    University of Freiburg
    biomass-ratio hypothesis - biomass recovery - disturbance intensity - niche-complementarity hypothesis - stand thinning (refinement) - selective logging
    1.Forest recovery following management interventions is important to maintain ecosystem functioning and the provision of ecosystem services. It remains, however, largely unclear how aboveground biomass (AGB) recovery of species-rich tropical forests is affected by disturbance intensity and post-disturbance (remaining) tree-community attributes, following logging and thinning interventions. 2.We investigated whether annual AGB increment (∆AGB) decreases with management-related disturbance intensity (disturbance hypothesis), and increases with the diversity (niche-complementarity hypothesis) and the community-weighted mean (CWM) of acquisitive traits of dominant species (biomass-ratio hypothesis) in the remaining tree community. 3.We analysed data from a long-term forest-management experiment in the Brazilian Amazon over two recovery periods: post-logging (1983-1989) and post-thinning (1995-2012). We computed the ∆AGB of surviving trees, recruit trees and of the total tree community. Disturbance intensity was quantified as basal area reduction and basal area remaining. Remaining diversity (taxonomic, functional and structural) and CWM of five functional traits linked to biomass productivity (specific leaf area, leaf nitrogen and phosphorous concentration, leaf toughness and wood density) were calculated for the post-intervention inventories. Predictors were related to response variables using multiple linear regressions and structural equation modelling. 4.We found support for the disturbance hypothesis in both recovery periods. AGB increment of survivors and of the total tree community increased with basal area remaining, indicating the importance of remaining growing stock for biomass recovery. Conversely, AGB increment of recruit trees increased with basal area reduction because changes in forest structure increased resource availability for young trees. We did not find consistent support for the niche-complementarity and biomass-ratio hypotheses, possibly because of a high redundancy in these extremely species-rich forests. 5.Synthesis and applications. The intensity of disturbance through management, expressed as basal area reduction and basal area remaining, was consistently more important for explaining forest biomass recovery following harvesting and thinning than remaining diversity or trait composition. This points to the importance of controlling logging and thinning intensity in forests of the eastern Amazon. Low to moderate harvesting intensities permitted by the current legislation for the Brazilian Amazon (30 m³ ha−1) will likely not impair biomass recovery in these forests.
    Data from: Biodiversity in species, traits and structure determines carbon stocks and uptake in tropical forests
    Sande, M.T. van der; Poorter, L. ; Kooistra, L. ; Balvanera, Patricia ; Thonicke, Kirsten ; Thompson, Jill ; Arets, E.J.M.M. ; Garcia-Alaniz, Nashieli ; Jones, L. ; Mora, Francisco ; Mwampamba, T.H. ; Parr, T. ; Pena Claros, M. - \ 2018
    Wageningen University & Research
    biodiversity-ecosystem functioning - biomass dynamics - biomass growth - climate change mitigation - functional traits - species diversity - tropical forest
    Impacts of climate change require that society urgently develops ways to reduce amounts of carbon in the atmosphere. Tropical forests present an important opportunity, as they take up and store large amounts of carbon. It is often suggested that forests with high biodiversity have large stocks and high rates of carbon uptake. Evidence is, however, scattered across geographic areas and scales, and it remains unclear whether biodiversity is just a co‐benefit or also a requirement for the maintenance of carbon stocks and uptake. Here, we perform a quantitative review of empirical studies that analyzed the relationships between plant biodiversity attributes and carbon stocks and carbon uptake in tropical forests. Our results show that biodiversity attributes related to species, traits or structure significantly affect carbon stocks or uptake in 64% of the evaluated relationships. Average vegetation attributes (community‐mean traits and structural attributes) are more important for carbon stocks, whereas variability in vegetation attributes (i.e., taxonomic diversity) is important for both carbon stocks and uptake. Thus, different attributes of biodiversity have complementary effects on carbon stocks and uptake. These biodiversity effects tend to be more often significant in mature forests at broad spatial scales than in disturbed forests at local spatial scales. Biodiversity effects are also more often significant when confounding variables are not included in the analyses, highlighting the importance of performing a comprehensive analysis that adequately accounts for environmental drivers. In summary, biodiversity is not only a co‐benefit, but also a requirement for short‐ and long‐term maintenance of carbon stocks and enhancement of uptake. Climate change policies should therefore include the maintenance of multiple attributes of biodiversity as an essential requirement to achieve long‐term climate change mitigation goals.
    Disturbance intensity is a stronger driver of biomass recovery than remaining tree-community attributes in a managed Amazonian forest
    Avila, Angel L. de; Sande, M.T. van der; Dormann, C.F. ; Pena Claros, M. ; Poorter, L. ; Mazzei, Lucas ; Ruschel, Ademir Roberto ; Silva, José N.M. ; Carvalho, J.O.P. ; Bauhus, J. - \ 2018
    Journal of Applied Ecology 55 (2018)4. - ISSN 0021-8901 - p. 1647 - 1657.
    Forest recovery following management interventions is important to maintain ecosystem functioning and the provision of ecosystem services. It remains, however, largely unclear how above‐ground biomass (AGB) recovery of species‐rich tropical forests is affected by disturbance intensity and post‐disturbance (remaining) tree‐community attributes, following logging and thinning interventions. We investigated whether annual AGB increment (∆AGB) decreases with management‐related disturbance intensity (disturbance hypothesis), and increases with the diversity (niche‐complementarity hypothesis) and the community‐weighted mean (CWM) of acquisitive traits of dominant species (biomass‐ratio hypothesis) in the remaining tree community. We analysed data from a long‐term forest‐management experiment in the Brazilian Amazon over two recovery periods: post‐logging (1983–1989) and post‐thinning (1995–2012). We computed the ∆AGB of surviving trees, recruit trees and of the total tree community. Disturbance intensity was quantified as basal area reduction and basal area remaining. Remaining diversity (taxonomic, functional and structural) and CWM of five functional traits linked to biomass productivity (specific leaf area, leaf nitrogen and phosphorous concentration, leaf toughness and wood density) were calculated for the post‐intervention inventories. Predictors were related to response variables using multiple linear regressions and structural equation modelling.

    We found support for the disturbance hypothesis in both recovery periods. AGB increment of survivors and of the total tree community increased with basal area remaining, indicating the importance of remaining growing stock for biomass recovery. Conversely, AGB increment of recruit trees increased with basal area reduction because changes in forest structure increased resource availability for young trees. We did not find consistent support for the niche‐complementarity and biomass‐ratio hypotheses, possibly because of a high redundancy in these extremely species‐rich forests. Synthesis and applications. The intensity of disturbance through management, expressed as basal area reduction and basal area remaining, was consistently more important for explaining forest biomass recovery following harvesting and thinning than remaining diversity or trait composition. This points to the importance of controlling logging and thinning intensity in forests of the eastern Amazon. Given the high intervention intensities applied in this experiment, it is likely that low to moderate harvesting intensities permitted by the current legislation for the Brazilian Amazon (30 m³/ha) will not impair biomass recovery in these forests.
    Soil fertility and species traits, but not diversity, drive productivity and biomass stocks in a Guyanese tropical rainforest
    Sande, M.T. van der; Arets, E.J.M.M. ; Pena Claros, M. ; Hoosbeek, M.R. ; Caceres-Siani, Yasmani ; Hout, P. van de; Poorter, L. - \ 2018
    Functional Ecology 32 (2018)2. - ISSN 0269-8463 - p. 461 - 474.
    1.Tropical forests store and sequester large amounts of carbon in above- and below-ground plant biomass and soil organic matter (SOM), but how these are driven by abiotic and biotic factors remains poorly understood.
    2.Here, we test the effects of abiotic factors (light variation, caused by logging disturbance, and soil fertility) and biotic factors (species richness and functional trait composition) on biomass stocks (above-ground biomass, fine root biomass), SOM and productivity in a relatively monodominant Guyanese tropical rainforest. This forest grows on nutrient-poor soils and has few species that contribute most to total abundance. We, therefore, expected strong effects of soil fertility and species’ traits that determine resource acquisition and conservation, but not of diversity. We evaluated 6 years of data for 30 0.4-ha plots and tested hypotheses using structural equation models.
    3.Disturbance increased productivity but decreased above-ground biomass stocks. Soil phosphorus (P) enhanced above-ground biomass and productivity, whereas soil nitrogen reduced fine root biomass. In contrast to expectations, trait values representing acquisitive strategies (e.g. high leaf nutrient concentration) increased biomass stocks, possibly because they indicate higher nutrient absorption and thus higher biomass build-up. However, under harsh conditions where biomass increase is slow, acquisitive trait values may increase respiration and vulnerability to hazards and therefore increase biomass loss. As expected, species richness did not affect productivity.
    4.We conclude that light availability (through disturbance) and soil fertility—especially P—strongly limit forest biomass productivity and stocks in this Guyanese forest. Low P availability may cause strong environmental filtering, which in turn results in a small set of dominant species. As a result, community trait composition but not species richness determines productivity and stocks of biomass and SOM in tropical forest on poor soils.

    Biodiversity and climate determine the functioning of Neotropical forests
    Poorter, L. ; Sande, M.T. van der; Arets, E.J.M.M. ; Ascarrunz, N. ; Enquist, B.J. ; Finegan, B. ; Licona, J.C. ; Martinez-Ramos, M. ; Mazzei, L. ; Meave, J. ; Munoz, R. ; Nytch, C.J. ; Oliveira, A.A. de; Perez-Garcia, E.A. ; Prado-Junior, J.A. ; Rodriguez-Velazquez, J. ; Ruschel, A.R. ; Salgado Negret, B. ; Schiavini, I. ; Swenson, N.G. ; Tenorio, E.A. ; Thompson, J. ; Toledo, M. ; Uriarte, M. ; Hout, P. van der; Zimmerman, J.K. ; Pena Claros, M. - \ 2017
    Wageningen University & Research
    biodiversity - biomass - carbon - ecosystem functioning - forest dynamics - productivity - soil fertility - tropical forest - water
    Tropical forests account for a quarter of the global carbon storage and a third of the terrestrial productivity. Few studies have teased apart the relative importance of environmental factors and forest attributes for ecosystem functioning, especially for the tropics. This study aims to relate aboveground biomass (AGB), biomass dynamics (i.e., net biomass productivity and its underlying demographic drivers: biomass recruitment, growth and mortality) to forest attributes (tree diversity, community-mean traits, and stand basal area) and environmental conditions (water availability, soil fertility and disturbance). We used data from 26 sites, 201 one-ha plots and >92,000 trees distributed across the Neotropics. We quantified for each site water availability and soil total exchangeable bases and for each plot three key community-weighted mean functional traits that are important for biomass stocks and productivity. We used structural equation models to test the hypothesis that all drivers have independent, positive effects on biomass stocks and dynamics. Of the relationships analysed, vegetation attributes were more frequently significantly associated with biomass stocks and dynamics than environmental conditions (in 67% versus 33% of the relationships). High climatic water availability increased biomass growth and stocks, light disturbance increased biomass growth, and soil bases had no effect. Rarefied tree species richness had consistent positive relationships with biomass stocks and dynamics, probably because of niche complementarity, but was not related to net biomass productivity. Community-mean traits were good predictors of biomass stocks and dynamics. Water availability has a strong positive effect on biomass stocks and growth, and a future predicted increase in (atmospheric) drought might, therefore, potentially reduce carbon storage. Forest attributes – including species diversity and community-weighted mean traits – have independent and important relationships with AGB stocks, dynamics, and ecosystem functioning, not only in relatively simple temperate systems, but also in structurally complex hyper-diverse tropical forests.
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