Papers by Fanny Langerwisch
Regional Environmental Change, 2015
A great challenge faced by the Amazon region is to maintain the ecosystem services provided by th... more A great challenge faced by the Amazon region is to maintain the ecosystem services provided by the pristine forest and its complex ecological processes, as well as the needs of the growing human population in the region, in face of global environmental changes and growing demands for land use. In the present study we analyze two different storylines linking different land use scenarios to possible impacts on the provision of ecosystem services in Amazonia: 1) a sustainable, environmental development scenario and 2) a chaotic, uncontrollable deforestation scenario. The future land cover maps are projected by a spatially explicit, dynamic land use model (LuccME) and are then used as inputs, in combination with climate change scenarios, to drive four biosphere models (INLAND, ORCHIDEE, JULES and LPJ). The biosphere models simulate changes in evapotranspiration and carbon fluxes and stocks. Finally, overlaying the biosphere model outputs with maps of roads or protected areas in the regi...
Journal of Ecology, 2015
ABSTRACT Forests around the world are changing as a result of human activity. These changes have ... more ABSTRACT Forests around the world are changing as a result of human activity. These changes have substantial impacts on the resilience of forests, possibly pushing them towards tipping points.The objective of this Special Feature is to present research that fosters the understanding of forest resilience and potential tipping points under global change. This editorial summarizes the key findings of the seven papers in this Special Feature and puts them in the wider context of resilience thinking.Synthesis. The contributions to this Special Feature show that resilience is a useful concept to understand ecosystem change but that we have to develop a better understanding of the mechanisms and feedback loops involved in forest resilience and potential tipping points. Finally, this Special Feature presents evidence about how resilience thinking is used to better understand and manage degraded forests.
Journal of Ecology, 2015
1. Anthropogenic global change compromises forest resilience, with profound impacts to ecosystem ... more 1. Anthropogenic global change compromises forest resilience, with profound impacts to ecosystem functions and services. This synthesis paper reflects on the current understanding of forest resilience and potential tipping points under environmental change and explores challenges to assessing responses using experiments, observations and models. 2. Forests are changing over a wide range of spatio-temporal scales, but it is often unclear whether these changes reduce resilience or represent a tipping point. Tipping points may arise from interactions across scales, as processes such as climate change, land-use change, invasive species or deforestation gradually erode resilience and increase vulnerability to extreme events. Studies covering interactions across different spatio-temporal scales are needed to further our understanding. 3. Combinations of experiments, observations and process-based models could improve our ability to project forest resilience and tipping points under global change. We discuss uncertainties in changing CO 2 concentration and quantifying tree mortality as examples. 4. Synthesis. As forests change at various scales, it is increasingly important to understand whether and how such changes lead to reduced resilience and potential tipping points. Understanding the mechanisms underlying forest resilience and tipping points would help in assessing risks to ecosystems and presents opportunities for ecosystem restoration and sustainable forest management.
Hydrology and Earth System Sciences, 2013
A key factor for the functioning and diversity of Amazonian rain forests is annual flooding. Howe... more A key factor for the functioning and diversity of Amazonian rain forests is annual flooding. However, increasing air temperature and higher precipitation variability, caused by climate change, are expected to shift the flooding regime, and thereby negatively impact floodplain ecosystems, their biodiversity and riverine ecosystem services dur-5 ing this century. To assess the effects of climate changes on the flooding regime, we use the Dynamic Global Vegetation and Hydrology Model LPJmL, enhanced by a scheme that realistically simulates floodable area and inundation. Regarding hydrograph and inundation area, simulation results under contemporary conditions compare well against observations. The changes of calculated river discharge and inundation, 10 15 decrease in the number of extremely dry years as well as a decrease of the probability of the occurrence of three consecutive extremely dry years. The total number of extremely wet years does not change drastically but the probability of three consecutive extremely wet years decreases by up to 30 % in the East and increases by up to 25 % in the West. These changes implicate significant shifts in regional vegetation and 20 climate, and will dramatically alter carbon and water cycles.
Global Change Biology, 2010
Global change includes multiple stressors to natural ecosystems ranging from direct climate and l... more Global change includes multiple stressors to natural ecosystems ranging from direct climate and land-use impacts to indirect degradation processes resulting from fire. Humid tropical forests are vulnerable to projected climate change and possible synergistic interactions with deforestation and fire, which may initiate a positive feedback to rising atmospheric CO 2 . Here, we present results from a multifactorial impact analysis that combined an ensemble of climate change models with feedbacks from deforestation and accidental fires to quantify changes in Amazon Basin carbon cycling. Using the LPJmL Dynamic Global Vegetation Model, we modelled spatio-temporal changes in net biome production (NBP); the difference between carbon fluxes from fire, deforestation, soil respiration and net primary production. By 2050, deforestation and fire (with no CO 2 increase or climate change) resulted in carbon losses of 7.4-20.3 Pg C with the range of uncertainty depending on socio-economic storyline. During the same time period, interactions between climate and land use either compensated for carbon losses due to wetter climate and CO 2 fertilization or exacerbated carbon losses from droughtinduced forest mortality (À20.1 to 1 4.3 Pg C). By the end of the 21st century, depending on climate projection and the rate of deforestation (including its interaction with fire), carbon stocks either increased (1 12.6 Pg C) or decreased (À40.6 Pg C). The synergistic effect of deforestation and fire with climate change contributed up to 26-36 Pg C of the overall decrease in carbon stocks. Agreement between climate projections (n 5 9), not accounting for deforestation and fire, in 2050 and 2098 was relatively low for the directional change in basin-wide NBP (19-37%) and aboveground live biomass (13-24%). The largest uncertainty resulted from climate projections, followed by implementation of ecosystem dynamics and deforestation. Our analysis partitions the drivers of tropical ecosystem change and is relevant for guiding mitigation and adaptation policy related to global change.
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Papers by Fanny Langerwisch