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Rapid expansion of settlements and related infrastructures is a global trend that comes with severe environmental, economic, and social costs. Steering urbanization toward well-balanced compactness is thus acknowledged as an important strategic orientation in UN Sustainable Development Goal 11 (SDG-11) via the SDG-indicator “Ratio of land consumption rate to population growth rate.” The EU’s simultaneous commitment to being “a frontrunner in implementing […] the SDGs” and to striving for “no net land take until 2050” calls for relating the concepts of land consumption and land take to each other. Drawing on an EU-centred questionnaire study, a focus group and a literature review, we scrutinize definitions of land consumption and land take, seeking to show how they are interrelated, and questioning the comparability of respective indicators. We argue that conceptual clarifications and a bridging of the two notions are much needed, and that the precision required for definitions and applications is context-dependent. While approximate understandings may suffice for general communication and dissemination objectives, accurate and consistent interpretations of the discussed concepts seem indispensable for monitoring and reporting purposes. We propose ways of addressing existing ambiguities and suggest prioritizing the term land take in the EU context. Thereby, we aim to enhance conceptual clarity around land consumption and land take—a precondition for solidly informing respective policies and decisions.
Elisabeth Marquard; Stephan Bartke; Judith Gifreu I Font; Alois Humer; Arend Jonkman; Evelin Jürgenson; Naja Marot; Lien Poelmans; Blaž Repe; Robert Rybski; Christoph Schröter-Schlaack; Jaroslava Sobocká; Michael Tophøj Sørensen; Eliška Vejchodská; Athena Yiannakou; Jana Bovet. Land Consumption and Land Take: Enhancing Conceptual Clarity for Evaluating Spatial Governance in the EU Context. Sustainability 2020, 12, 8269 .
AMA StyleElisabeth Marquard, Stephan Bartke, Judith Gifreu I Font, Alois Humer, Arend Jonkman, Evelin Jürgenson, Naja Marot, Lien Poelmans, Blaž Repe, Robert Rybski, Christoph Schröter-Schlaack, Jaroslava Sobocká, Michael Tophøj Sørensen, Eliška Vejchodská, Athena Yiannakou, Jana Bovet. Land Consumption and Land Take: Enhancing Conceptual Clarity for Evaluating Spatial Governance in the EU Context. Sustainability. 2020; 12 (19):8269.
Chicago/Turabian StyleElisabeth Marquard; Stephan Bartke; Judith Gifreu I Font; Alois Humer; Arend Jonkman; Evelin Jürgenson; Naja Marot; Lien Poelmans; Blaž Repe; Robert Rybski; Christoph Schröter-Schlaack; Jaroslava Sobocká; Michael Tophøj Sørensen; Eliška Vejchodská; Athena Yiannakou; Jana Bovet. 2020. "Land Consumption and Land Take: Enhancing Conceptual Clarity for Evaluating Spatial Governance in the EU Context." Sustainability 12, no. 19: 8269.
Making agriculture sustainable is a global challenge. In the European Union (EU), the Common Agricultural Policy (CAP) is failing with respect to biodiversity, climate, soil, land degradation as well as socio‐economic challenges. The European Commission's proposal for a CAP post‐2020 provides a scope for enhanced sustainability. However, it also allows Member States to choose low‐ambition implementation pathways. It therefore remains essential to address citizens' demands for sustainable agriculture and rectify systemic weaknesses in the CAP, using the full breadth of available scientific evidence and knowledge. Concerned about current attempts to dilute the environmental ambition of the future CAP, and the lack of concrete proposals for improving the CAP in the draft of the European Green Deal, we call on the European Parliament, Council and Commission to adopt 10 urgent action points for delivering sustainable food production, biodiversity conservation and climate mitigation. Knowledge is available to help moving towards evidence‐based, sustainable European agriculture that can benefit people, nature and their joint futures. The statements made in this article have the broad support of the scientific community, as expressed by above 3,600 signatories to the preprint version of this manuscript. The list can be found here (https://doi.org/10.5281/zenodo.3685632). A free Plain Language Summary can be found within the Supporting Information of this article.
Guy Pe'er; Aletta Bonn; Helge Bruelheide; Petra Dieker; Nico Eisenhauer; Peter H. Feindt; Gregor Hagedorn; Bernd Hansjürgens; Irina Herzon; Ângela Lomba; Elisabeth Marquard; Francisco Moreira; Heike Nitsch; Rainer Oppermann; Andrea Perino; Norbert Röder; Christian Schleyer; Stefan Schindler; Christine Wolf; Yves Zinngrebe; Sebastian Lakner. Action needed for the EU Common Agricultural Policy to address sustainability challenges. People and Nature 2020, 2, 305 -316.
AMA StyleGuy Pe'er, Aletta Bonn, Helge Bruelheide, Petra Dieker, Nico Eisenhauer, Peter H. Feindt, Gregor Hagedorn, Bernd Hansjürgens, Irina Herzon, Ângela Lomba, Elisabeth Marquard, Francisco Moreira, Heike Nitsch, Rainer Oppermann, Andrea Perino, Norbert Röder, Christian Schleyer, Stefan Schindler, Christine Wolf, Yves Zinngrebe, Sebastian Lakner. Action needed for the EU Common Agricultural Policy to address sustainability challenges. People and Nature. 2020; 2 (2):305-316.
Chicago/Turabian StyleGuy Pe'er; Aletta Bonn; Helge Bruelheide; Petra Dieker; Nico Eisenhauer; Peter H. Feindt; Gregor Hagedorn; Bernd Hansjürgens; Irina Herzon; Ângela Lomba; Elisabeth Marquard; Francisco Moreira; Heike Nitsch; Rainer Oppermann; Andrea Perino; Norbert Röder; Christian Schleyer; Stefan Schindler; Christine Wolf; Yves Zinngrebe; Sebastian Lakner. 2020. "Action needed for the EU Common Agricultural Policy to address sustainability challenges." People and Nature 2, no. 2: 305-316.
Global change has complex eco-evolutionary consequences for organisms and ecosystems, but related concepts (e.g., novel ecosystems) do not cover their full range. Here we propose an umbrella concept of “ecological novelty” comprising (1) a site-specific and (2) an organism-centered, eco-evolutionary perspective. Under this umbrella, complementary options for studying and communicating effects of global change on organisms, ecosystems, and landscapes can be included in a toolbox. This allows researchers to address ecological novelty from different perspectives, e.g., by defining it based on (a) categorical or continuous measures, (b) reference conditions related to sites or organisms, and (c) types of human activities. We suggest striving for a descriptive, non-normative usage of the term “ecological novelty” in science. Normative evaluations and decisions about conservation policies or management are important, but require additional societal processes and engagement with multiple stakeholders.
Tina Heger; Maud Bernard-Verdier; Arthur Gessler; Alex D Greenwood; Hans-Peter Grossart; Monika Hilker; Silvia Keinath; Ingo Kowarik; Christoph Kueffer; Elisabeth Marquard; Johannes Müller; Stephanie Niemeier; Gabriela Onandia; Jana Petermann; Matthias Rillig; Mark-Oliver Rödel; Wolf-Christian Saul; Conrad Schittko; Klement Tockner; Jasmin Joshi; Jonathan M Jeschke. Towards an Integrative, Eco-Evolutionary Understanding of Ecological Novelty: Studying and Communicating Interlinked Effects of Global Change. BioScience 2019, 69, 888 -899.
AMA StyleTina Heger, Maud Bernard-Verdier, Arthur Gessler, Alex D Greenwood, Hans-Peter Grossart, Monika Hilker, Silvia Keinath, Ingo Kowarik, Christoph Kueffer, Elisabeth Marquard, Johannes Müller, Stephanie Niemeier, Gabriela Onandia, Jana Petermann, Matthias Rillig, Mark-Oliver Rödel, Wolf-Christian Saul, Conrad Schittko, Klement Tockner, Jasmin Joshi, Jonathan M Jeschke. Towards an Integrative, Eco-Evolutionary Understanding of Ecological Novelty: Studying and Communicating Interlinked Effects of Global Change. BioScience. 2019; 69 (11):888-899.
Chicago/Turabian StyleTina Heger; Maud Bernard-Verdier; Arthur Gessler; Alex D Greenwood; Hans-Peter Grossart; Monika Hilker; Silvia Keinath; Ingo Kowarik; Christoph Kueffer; Elisabeth Marquard; Johannes Müller; Stephanie Niemeier; Gabriela Onandia; Jana Petermann; Matthias Rillig; Mark-Oliver Rödel; Wolf-Christian Saul; Conrad Schittko; Klement Tockner; Jasmin Joshi; Jonathan M Jeschke. 2019. "Towards an Integrative, Eco-Evolutionary Understanding of Ecological Novelty: Studying and Communicating Interlinked Effects of Global Change." BioScience 69, no. 11: 888-899.
Credibility, relevance and legitimacy are often cited as determinants of the effectiveness of interfaces between science and environmental policy and serve as criteria for their evaluation. However, these concepts are hazy and have a variety of meanings. In practice, the systematic evaluation of science–policy interfaces according to credibility, relevance and legitimacy is subject to a number of difficulties and is rarely done. In this paper we offer some clarification of these concepts and show how they influence the perception and evaluation of science–policy interfaces. Our findings reveal that, while the attributes of credibility, relevance and legitimacy are helpful when reflecting on the effectiveness of science–policy interfaces, they are difficult to apply as criteria when evaluating these interfaces. To apply these concepts in a meaningful way to the task of evaluation they need to be defined specifically for the particular context of the science–policy interface concerned.
Ulrich Heink; Elisabeth Marquard; Katja Heubach; Kurt Jax; Carolin Kugel; Carsten Neßhöver; Rosmarie K. Neumann; Axel Paulsch; Sebastian Tilch; Johannes Timaeus; Marie Vandewalle; C. Nesshover. Conceptualizing credibility, relevance and legitimacy for evaluating the effectiveness of science–policy interfaces: Challenges and opportunities. Science and Public Policy 2015, 42, 676 -689.
AMA StyleUlrich Heink, Elisabeth Marquard, Katja Heubach, Kurt Jax, Carolin Kugel, Carsten Neßhöver, Rosmarie K. Neumann, Axel Paulsch, Sebastian Tilch, Johannes Timaeus, Marie Vandewalle, C. Nesshover. Conceptualizing credibility, relevance and legitimacy for evaluating the effectiveness of science–policy interfaces: Challenges and opportunities. Science and Public Policy. 2015; 42 (5):676-689.
Chicago/Turabian StyleUlrich Heink; Elisabeth Marquard; Katja Heubach; Kurt Jax; Carolin Kugel; Carsten Neßhöver; Rosmarie K. Neumann; Axel Paulsch; Sebastian Tilch; Johannes Timaeus; Marie Vandewalle; C. Nesshover. 2015. "Conceptualizing credibility, relevance and legitimacy for evaluating the effectiveness of science–policy interfaces: Challenges and opportunities." Science and Public Policy 42, no. 5: 676-689.
The role and design of global expert organizations such as the Intergovernmental Panel on Climate Change (IPCC) or the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) needs rethinking. Acknowledging that a one-size-fits-all model does not exist, we suggest a reflexive turn that implies treating the governance of expertise as a matter of political contestation.
Silke Beck; Maud Borie; Jason Chilvers; Alejandro Esguerra; Katja Heubach; Mike Hulme; Rolf Lidskog; Eva Lövbrand; Elisabeth Marquard; Clark Miller; Tahani Nadim; Carsten Neßhöver; Josef Settele; Esther Turnhout; Eleftheria Vasileiadou; Christoph Görg. Towards a Reflexive Turn in the Governance of Global Environmental Expertise. The Cases of the IPCC and the IPBES. GAIA - Ecological Perspectives for Science and Society 2014, 23, 80 -87.
AMA StyleSilke Beck, Maud Borie, Jason Chilvers, Alejandro Esguerra, Katja Heubach, Mike Hulme, Rolf Lidskog, Eva Lövbrand, Elisabeth Marquard, Clark Miller, Tahani Nadim, Carsten Neßhöver, Josef Settele, Esther Turnhout, Eleftheria Vasileiadou, Christoph Görg. Towards a Reflexive Turn in the Governance of Global Environmental Expertise. The Cases of the IPCC and the IPBES. GAIA - Ecological Perspectives for Science and Society. 2014; 23 (2):80-87.
Chicago/Turabian StyleSilke Beck; Maud Borie; Jason Chilvers; Alejandro Esguerra; Katja Heubach; Mike Hulme; Rolf Lidskog; Eva Lövbrand; Elisabeth Marquard; Clark Miller; Tahani Nadim; Carsten Neßhöver; Josef Settele; Esther Turnhout; Eleftheria Vasileiadou; Christoph Görg. 2014. "Towards a Reflexive Turn in the Governance of Global Environmental Expertise. The Cases of the IPCC and the IPBES." GAIA - Ecological Perspectives for Science and Society 23, no. 2: 80-87.
Numerous studies have reported positive effects of species richness on plant community productivity. Such biodiversity effects are usually quantified by comparing the performance of plant mixtures with reference monocultures. However, several mechanisms, such as the lack of resource complementarity and facilitation or the accumulation of detrimental agents, suggest that monocultures are more likely than mixtures to deteriorate over time. Increasing biodiversity effects over time could therefore result from declining monocultures instead of reflecting increases in the functioning of mixtures. Commonly, the latter is assumed when positive trends in biodiversity effects occur. Here, we analysed the performance of 60 grassland species growing in monocultures and mixtures over 9 years in a biodiversity experiment to clarify whether their temporal biomass dynamics differed and whether a potential decline of monocultures contributed significantly to the positive net biodiversity effect observed. Surprisingly, individual species’ populations produced, on average, significantly more biomass per unit area when growing in monoculture than when growing in mixture. Over time, productivity of species decreased at a rate that was, on average, slightly more negative in monocultures than in mixtures. The mean net biodiversity effect across all mixtures was continuously positive and ranged between 64–217 g per m2. Short-term increases in the mean net biodiversity effect were only partly due to deteriorating monocultures and were strongly affected by particular species gaining dominance in mixtures in the respective years. We conclude that our species performed, on average, comparably in monocultures and mixtures; monoculture populations being slightly more productive than mixture populations but this trend decreased over time. This suggested that negative feedbacks had not yet affected monocultures strongly but could potentially become more evident in the future. Positive biodiversity effects on aboveground productivity were heavily driven by a small, but changing, set of species that behaved differently from the average species.
Elisabeth Marquard; Bernhard Schmid; Christiane Roscher; Enrica De Luca; Karin Nadrowski; Wolfgang W. Weisser; Alexandra Weigelt. Changes in the Abundance of Grassland Species in Monocultures versus Mixtures and Their Relation to Biodiversity Effects. PLoS ONE 2013, 8, e75599 .
AMA StyleElisabeth Marquard, Bernhard Schmid, Christiane Roscher, Enrica De Luca, Karin Nadrowski, Wolfgang W. Weisser, Alexandra Weigelt. Changes in the Abundance of Grassland Species in Monocultures versus Mixtures and Their Relation to Biodiversity Effects. PLoS ONE. 2013; 8 (9):e75599.
Chicago/Turabian StyleElisabeth Marquard; Bernhard Schmid; Christiane Roscher; Enrica De Luca; Karin Nadrowski; Wolfgang W. Weisser; Alexandra Weigelt. 2013. "Changes in the Abundance of Grassland Species in Monocultures versus Mixtures and Their Relation to Biodiversity Effects." PLoS ONE 8, no. 9: e75599.
1. While positive effects of biodiversity on temporal stability of communities have been demonstrated in theoretical and empirical studies, diversity–stability relationships at the population level remain poorly understood. 2. We investigated temporal variability of plant populations in experimental grassland plots of varying species richness (1, 2, 4, 8, 16–60 species), functional group richness and composition (presence/absence of legumes × grasses × small herbs × tall herbs) in a long‐term biodiversity experiment from 2003 to 2009 (‘Jena Experiment’). 3. Average population stability, defined as the reciprocal of the coefficient of variation of above‐ground biomass production over time, differed largely between species but was generally higher in grasses and small herbs than in legumes and tall herbs. Furthermore, population stability was positively related to a species’ proportional contribution to community biomass. Thus, an increasing number of subordinate species explained lower average population stabilities at higher diversity levels. 4. A negative covariance (CV) across all species‐richness levels suggested negatively correlated species dynamics. Species belonging to different functional groups fluctuated asynchronously, while species dynamics within functional groups were more synchronous. Community‐wide species synchrony decreased with increasing species richness, and temporal stability at the community level increased. 5. Synthesis: Our results suggest that diversity–stability relationships are driven by fluctuations in the population biomass of individual species which are less synchronized in more diverse than in less diverse mixtures and monocultures. Dominant plant species tend to be more stabilized than subdominant species, independently of community species richness. However, asynchrony of population dynamics outweighs decreasing population stability with increasing species richness, resulting in higher temporal stability at the plant community level.
Christiane Roscher; Alexandra Weigelt; Raphael Proulx; Elisabeth Marquard; Jens Schumacher; Wolfgang Weisser; Bernhard Schmid. Identifying population- and community-level mechanisms of diversity-stability relationships in experimental grasslands. Journal of Ecology 2011, 99, 1460 -1469.
AMA StyleChristiane Roscher, Alexandra Weigelt, Raphael Proulx, Elisabeth Marquard, Jens Schumacher, Wolfgang Weisser, Bernhard Schmid. Identifying population- and community-level mechanisms of diversity-stability relationships in experimental grasslands. Journal of Ecology. 2011; 99 (6):1460-1469.
Chicago/Turabian StyleChristiane Roscher; Alexandra Weigelt; Raphael Proulx; Elisabeth Marquard; Jens Schumacher; Wolfgang Weisser; Bernhard Schmid. 2011. "Identifying population- and community-level mechanisms of diversity-stability relationships in experimental grasslands." Journal of Ecology 99, no. 6: 1460-1469.
This data set contains species‐specific biomass and cover data as well as community leaf area index (LAI) and height from a large grassland biodiversity experiment (Jena Experiment). In this experiment, 82 grassland plots of 20 × 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, and tall and small herbs). In May 2002, varying numbers of plant species were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16, and 60 species) and functional richness (1, 2, 3, and 4 functional groups). Plots were maintained by biannual weeding and mowing. The data set encompasses the 2002–2008 May and August biomass harvests from 3–4 subplots of 0.2 × 0.5 m per experimental plot sorted to species. Moreover, plant species and community cover estimated in an approximately 9‐m2 subplot per plot are included in the data set. Each biomass harvest was accompanied by measurements of vegetation height and LAI per plot. Analyses of the community biomass data have identified species richness as well as functional group composition as important drivers of a positive biodiversity–productivity relationship. The data set can be used to study a variety of questions about how plant community composition and structure respond to changes in species richness and functional diversity over time. Sampling is ongoing, and new data will be added. The complete data sets corresponding to abstracts published in the Data Papers section of the journal are published electronically in Ecological Archives at 〈http://esapubs.org/archive〉. (The accession number for each Data Paper is given directly beneath the title.)
Alexandra Weigelt; Elisabeth Marquard; Vicky M. Temperton; Christiane Roscher; Christoph Scherber; Peter N. Mwangi; Stefanievon Felten; Nina Buchmann; Bernhard Schmid; Ernst-Detlef Schulze; Wolfgang W. Weisser. The Jena Experiment: six years of data from a grassland biodiversity experiment. Ecology 2010, 91, 930 -931.
AMA StyleAlexandra Weigelt, Elisabeth Marquard, Vicky M. Temperton, Christiane Roscher, Christoph Scherber, Peter N. Mwangi, Stefanievon Felten, Nina Buchmann, Bernhard Schmid, Ernst-Detlef Schulze, Wolfgang W. Weisser. The Jena Experiment: six years of data from a grassland biodiversity experiment. Ecology. 2010; 91 (3):930-931.
Chicago/Turabian StyleAlexandra Weigelt; Elisabeth Marquard; Vicky M. Temperton; Christiane Roscher; Christoph Scherber; Peter N. Mwangi; Stefanievon Felten; Nina Buchmann; Bernhard Schmid; Ernst-Detlef Schulze; Wolfgang W. Weisser. 2010. "The Jena Experiment: six years of data from a grassland biodiversity experiment." Ecology 91, no. 3: 930-931.
Plant diversity has been shown to increase community biomass in experimental communities, but the mechanisms resulting in such positive biodiversity effects have remained largely unknown. We used a large‐scale six‐year biodiversity experiment near Jena, Germany, to examine how aboveground community biomass in grasslands is affected by different components of plant diversity and thereby infer the mechanisms that may underlie positive biodiversity effects. As components of diversity we defined the number of species (1–16), number of functional groups (1–4), presence of functional groups (legumes, tall herbs, small herbs, and grasses) and proportional abundance of functional groups. Using linear models, replacement series on the level of functional groups, and additive partitioning on the level of species, we explored whether the observed biodiversity effects originated from disproportionate effects of single functional groups or species or from positive interactions between them. Aboveground community biomass was positively related to the number of species measured across functional groups as well as to the number of functional groups measured across different levels of species richness. Furthermore, increasing the number of species within functional groups increased aboveground community biomass, indicating that species within functional groups were not redundant with respect to biomass production. A positive relationship between the number of functional groups and aboveground community biomass within a particular level of species richness suggested that complementarity was larger between species belonging to different rather than to the same functional groups. The presence of legumes or tall herbs had a strong positive impact on aboveground community biomass whereas the presence of small herbs or grasses had on average no significant effect. Two‐ and three‐way interactions between functional group presences were weak, suggesting that their main effects were largely additive. Replacement series analyses on the level of functional groups revealed strong transgressive overyielding and relative yields >1, indicating facilitation. On the species level, we found strong complementarity effects that increased over time while selection effects due to disproportionate contributions of particular species decreased over time. We conclude that transgressive overyielding between functional groups and species richness effects within functional groups caused the positive biodiversity effects on aboveground community biomass in our experiment.
Elisabeth Marquard; Alexandra Weigelt; Vicky Temperton; Christiane Roscher; Jens Schumacher; Nina Buchmann; Markus Fischer; Wolfgang Weisser; Bernhard Schmid. Plant species richness and functional composition drive overyielding in a six-year grassland experiment. Ecology 2009, 90, 3290 -3302.
AMA StyleElisabeth Marquard, Alexandra Weigelt, Vicky Temperton, Christiane Roscher, Jens Schumacher, Nina Buchmann, Markus Fischer, Wolfgang Weisser, Bernhard Schmid. Plant species richness and functional composition drive overyielding in a six-year grassland experiment. Ecology. 2009; 90 (12):3290-3302.
Chicago/Turabian StyleElisabeth Marquard; Alexandra Weigelt; Vicky Temperton; Christiane Roscher; Jens Schumacher; Nina Buchmann; Markus Fischer; Wolfgang Weisser; Bernhard Schmid. 2009. "Plant species richness and functional composition drive overyielding in a six-year grassland experiment." Ecology 90, no. 12: 3290-3302.
1. Positive effects of biodiversity on plant productivity may result from diversity-induced changes in the size or density of individual plants, yet these two possibilities have never been tested at the same time in a biodiversity experiment with a large species pool. Here, we distinguish between size effects and density effects on plant productivity, using data from 198 experimental grassland communities that contained 1-16 species. Plant modules such as tillers or rosettes were defined as relevant units, being equivalent to plant individuals in the majority of species. 2. In agreement with previous studies, we found positive effects of species richness on above-ground productivity. We show that this positive biodiversity effect resulted from diversity-induced increases in module density rather than from increases in module size. In contrast, variation in productivity within diversity levels was related to module size rather than module density. 3. The size-density relationships varied among plant functional groups and among species but their average response to increasing species richness paralleled the pattern observed at the level of the entire plant communities: species richness had a positive effect on above-ground species biomass and species module density but not on species module size. Twenty-four out of 26 overyielding species had denser populations and 25 out of 28 underyielding species had smaller modules in mixtures than in monocultures. 4. Synthesis. In grasslands, an increase in community productivity must involve an increase in plant size or density. We found that diversity-induced increases in productivity were related to diversity-induced increases in density, whereas diversity-independent increases in productivity were related to increases in plant size. Our results suggest that increased density of overyielding species in mixtures was the main driver of the positive biodiversity-productivity relationship in our experiment. We conclude that the mechanisms leading to enhanced productivity of species-rich as compared with species-poor communities cannot be derived from mechanisms explaining high productivity within communities that contain a particular number of species. [References: 50
Elisabeth Marquard; Alexandra Weigelt; Christiane Roscher; Marlén Gubsch; Annett Lipowsky; Bernhard Schmid. Positive biodiversity-productivity relationship due to increased plant density. Journal of Ecology 2009, 97, 696 -704.
AMA StyleElisabeth Marquard, Alexandra Weigelt, Christiane Roscher, Marlén Gubsch, Annett Lipowsky, Bernhard Schmid. Positive biodiversity-productivity relationship due to increased plant density. Journal of Ecology. 2009; 97 (4):696-704.
Chicago/Turabian StyleElisabeth Marquard; Alexandra Weigelt; Christiane Roscher; Marlén Gubsch; Annett Lipowsky; Bernhard Schmid. 2009. "Positive biodiversity-productivity relationship due to increased plant density." Journal of Ecology 97, no. 4: 696-704.
1. Hybridization between crops and their wild relatives may enhance invasiveness and change their niche dynamics. This is regarded as a major biosafety problem in terms of the development of noxious, invasive weeds and the loss of the genetic identity of native species. Modelling the consequences of hybridization is becoming an important tool for risk assessment. 2. We conducted a sensitivity analysis of a stochastic hybridization model, predicting changes in genotypic population composition. The model includes various classes of hybrids between Lactuca sativa (lettuce) and its wild relative L. serriola, and is based on empirical demographic measurements of fitness (λ). 3. We calculated the sensitivity of these transitions and of the following model parameters: outcrossing rate, the temporal frequency of crop presence, early hybrid fitness, hybrid vigour breakdown rate and assumed fitness of advanced generation hybrids. 4. In a non-stochastic simulation, the wild relative was displaced by more vigorous hybrids. The relative fitness of late generation hybrids in relation to the fitness of the wild taxon had the strongest effects on the population composition in the long term. 5. The outcrossing rate affected the estimated population composition strongly but the proportional impact of this parameter was low compared to the effect of hybrid fitness. Moreover, the stochastic simulations showed that the level of stochasticity had only a small effect on the sensitivity of population growth rates to changes in any of the model parameters, except for changes in the fitness of the wild taxon. 6. Synthesis and applications. It is essential to determine the relative fitness level of advanced generation hybrids, as this has a much stronger proportional effect than other factors. Future risk assessment should focus more on long-term fitness effects and not only on the outcrossing rate and the early establishment of hybrids. Experiments with multiple generations and analysis of hybrid vigour in modelling efforts would yield better predictions of which traits would be likely to introgress, and at what speed. This would be of benefit in the decision-making process and in future monitoring after crop release, for example of transgenes
Danny Hooftman; J. Gerard B. Oostermeijer; Elisabeth Marquard; Hans (J.) C.M. Den Nijs. Modelling the consequences of cropwild relative gene flow: a sensitivity analysis of the effects of outcrossing rates and hybrid vigour breakdown inLactuca. Journal of Applied Ecology 2008, 45, 1094 -1103.
AMA StyleDanny Hooftman, J. Gerard B. Oostermeijer, Elisabeth Marquard, Hans (J.) C.M. Den Nijs. Modelling the consequences of cropwild relative gene flow: a sensitivity analysis of the effects of outcrossing rates and hybrid vigour breakdown inLactuca. Journal of Applied Ecology. 2008; 45 (4):1094-1103.
Chicago/Turabian StyleDanny Hooftman; J. Gerard B. Oostermeijer; Elisabeth Marquard; Hans (J.) C.M. Den Nijs. 2008. "Modelling the consequences of cropwild relative gene flow: a sensitivity analysis of the effects of outcrossing rates and hybrid vigour breakdown inLactuca." Journal of Applied Ecology 45, no. 4: 1094-1103.