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- ItemAdaptive responses of animals to climate change are most likely insufficient([London] : Nature Publishing Group UK, 2019) Radchuk, Viktoriia; Reed, Thomas; Teplitsky, Céline; van de Pol, Martijn; Charmantier, Anne; Hassall, Christopher; Adamík, Peter; Adriaensen, Frank; Ahola, Markus P.; Arcese, Peter; Avilés, Jesús Miguel; Balbontin, Javier; Berg, Karl S.; Borras, Antoni; Burthe, Sarah; Clobert, Jean; Dehnhard, Nina; de Lope, Florentino; Dhondt, André A.; Dingemanse, Niels J.; Doi, Hideyuki; Eeva, Tapio; Fickel, Joerns; Filella, Iolanda; Fossøy, Frode; Goodenough, Anne E.; Hall, Stephen J. G.; Hansson, Bengt; Harris, Michael; Hasselquist, Dennis; Hickler, Thomas; Joshi, Jasmin; Kharouba, Heather; Martínez, Juan Gabriel; Mihoub, Jean-Baptiste; Mills, James A.; Molina-Morales, Mercedes; Moksnes, Arne; Ozgul, Arpat; Parejo, Deseada; Pilard, Philippe; Poisbleau, Maud; Rousset, Francois; Rödel, Mark-Oliver; Scott, David; Senar, Juan Carlos; Stefanescu, Constanti; Stokke, Bård G.; Kusano, Tamotsu; Tarka, Maja; Tarwater, Corey E.; Thonicke, Kirsten; Thorley, Jack; Wilting, Andreas; Tryjanowski, Piotr; Merilä, Juha; Sheldon, Ben C.; Pape Møller, Anders; Matthysen, Erik; Janzen, Fredric; Dobson, F. Stephen; Visser, Marcel E.; Beissinger, Steven R.; Courtiol, Alexandre; Kramer-Schadt, StephanieBiological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species. © 2019, The Author(s).
- ItemContrasting and interacting changes in simulated spring and summer carbon cycle extremes in European ecosystems(Bristol : IOP Publishing, 2017) Sippel, Sebastian; Forkel, Matthias; Rammig, Anja; Thonicke, Kirsten; Flach, Milan; Heimann, Martin; Otto, Friederike E.L.; Reichstein, Markus; Mahecha, Miguel D.Climate extremes have the potential to cause extreme responses of terrestrial ecosystem functioning. However, it is neither straightforward to quantify and predict extreme ecosystem responses, nor to attribute these responses to specific climate drivers. Here, we construct a factorial experiment based on a large ensemble of process-oriented ecosystem model simulations driven by a regional climate model (12 500 model years in 1985–2010) in six European regions. Our aims are to (1) attribute changes in the intensity and frequency of simulated ecosystem productivity extremes (EPEs) to recent changes in climate extremes, CO2 concentration, and land use, and to (2) assess the effect of timing and seasonal interaction on the intensity of EPEs. Evaluating the ensemble simulations reveals that (1) recent trends in EPEs are seasonally contrasting: spring EPEs show consistent trends towards increased carbon uptake, while trends in summer EPEs are predominantly negative in net ecosystem productivity (i.e. higher net carbon release under drought and heat in summer) and close-to-neutral in gross productivity. While changes in climate and its extremes (mainly warming) and changes in CO2 increase spring productivity, changes in climate extremes decrease summer productivity neutralizing positive effects of CO2. Furthermore, we find that (2) drought or heat wave induced carbon losses in summer (i.e. negative EPEs) can be partly compensated by a higher uptake in the preceding spring in temperate regions. Conversely, however, carry-over effects from spring to summer that arise from depleted soil moisture exacerbate the carbon losses caused by climate extremes in summer, and are thus undoing spring compensatory effects. While the spring-compensation effect is increasing over time, the carry-over effect shows no trend between 1985–2010. The ensemble ecosystem model simulations provide a process-based interpretation and generalization for spring-summer interacting carbon cycle effects caused by climate extremes (i.e. compensatory and carry-over effects). In summary, the ensemble ecosystem modelling approach presented in this paper offers a novel route to scrutinize ecosystem responses to changing climate extremes in a probabilistic framework, and to pinpoint the underlying eco-physiological mechanisms.
- ItemAccelerated photosynthesis routine in LPJmL4(Katlenburg-Lindau : Copernicus, 2023) Niebsch, Jenny; Bloh, Werner von; Thonicke, Kirsten; Ramlau, RonnyThe increasing impacts of climate change require strategies for climate adaptation. Dynamic global vegetation models (DGVMs) are one type of multi-sectorial impact model with which the effects of multiple interacting processes in the terrestrial biosphere under climate change can be studied. The complexity of DGVMs is increasing as more and more processes, especially for plant physiology, are implemented. Therefore, there is a growing demand for increasing the computational performance of the underlying algorithms as well as ensuring their numerical accuracy. One way to approach this issue is to analyse the routines which have the potential for improved computational efficiency and/or increased accuracy when applying sophisticated mathematical methods. In this paper, the Farquhar–Collatz photosynthesis model under water stress as implemented in the Lund–Potsdam–Jena managed Land DGVM (4.0.002) was examined. We additionally tested the uncertainty of most important parameter of photosynthesis as an additional approach to improve model quality. We found that the numerical solution of a nonlinear equation, so far solved with the bisection method, could be significantly improved by using Newton’s method instead. The latter requires the computation of the derivative of the underlying function which is presented. Model simulations show a significantly lower number of iterations to solve the equation numerically and an overall run time reduction of the model of about 16 % depending on the chosen accuracy. Increasing the parameters θ and αC3 by 10 %, respectively, while keeping all other parameters at their original value, increased global gross primary production (GPP) by 2.384 and 9.542 GtC yr−1, respectively. The Farquhar–Collatz photosynthesis model forms the core component in many DGVMs and land surface models. An update in the numerical solution of the nonlinear equation in connection with adjusting globally important parameters to best known values can therefore be applied to similar photosynthesis models. Furthermore, this exercise can serve as an example for improving computationally costly routines while improving their mathematical accuracy.