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ERC

PASTFORWARD Report Summary

Project ID: 614839
Funded under: FP7-IDEAS-ERC
Country: Belgium

Mid-Term Report Summary - PASTFORWARD (Development trajectories of temperate forest plant communities under global change: combining hindsight and forecasting (PASTFORWARD))

PASTFORWARD - Development trajectories of temperate forest plant communities under global change: combining hindsight and forecasting.

The last decades are characterized by an upsurge of research on the impacts of global environmental changes on forests. Climate warming, atmospheric deposition of acidifying and eutrophying pollutants and land-use change are three of the most important threats to biodiversity in temperate forests. However, most studies focused on the effects of single factors over short time periods, such that our ability to predict the combined effects of multiple global change drivers over longer time periods remains rudimentary. The lack of knowledge on effects of global change drivers on forest herb layer communities is particularly striking, since the herb layer contains the largest part of vascular plant diversity in temperate forests and provides key ecosystem services. Therefore PASTFORWARD will build an integrative understanding of the interactive effects of land-use change, atmospheric deposition and climate warming on forest herb layer communities, starting from the insight that changes in herb layer communities are driven primarily by past land use, but can be modulated by atmospheric deposition, climate warming and forest management. As put forward by Perring et al. (2016), it is still largely ignored that sensible predictions of community development trajectories under global change can only be made by taking the land-use history into account, as legacies of past land use can leave century-long imprints on ecological communities in general and forest herb layer communities in particular.
Three complementary data sources (a database with resurveyed vegetation plots, field measurements in a pan-European network of resurvey plots, and a multi-factor experiment) combined with ecosystem modelling techniques are being used to test these predictions:
(1) Building upon the concepts how to combine biodiversity resurveys across regions to advance global change research outlined by Verheyen et al. (2017), a database comprising 1814 plot pairs (in time) from 40 different regions in temperate Europe has been compiled. In conjunction with trait values for herbaceous species from databases, and categorisations of expert-derived management histories for each dataset from 1800 we were – in line with our predictions - able to demonstrate interactions among land management legacies and contemporary environmental changes in determining plant community responses (Perring et al., in prep.).
(2) As the database does not contain data on environmental variables and only relatively crude information on the past land -use is available, the PASTFORWARD team has done standardized measurements on circa 192 resurvey plots distributed over 19 regions in temperate Europe. Within each region, plots with contrasting land-use history have been relocated and between regions we tried to maximize the gradients in climatic conditions and atmospheric deposition. Community data are currently being analysed, but this work has already let to methodological advancements on reconstructing land-use history trajectories from tree rings (Maes et al. submitted) and on the use of Baysian Belief Networks to translate historical information into operational ecological variables (Depauw et al., in prep.).
(3) To complement the database and observatory work, a large-scale multi-factor experiment, seeking to disentangle interacting effects of global change drivers has been set up in spring 2016. Twelve different model plant communities were planted in 384 mesocoms consisting of soil collected in ancient and recent forests distributed over eight regions in Europe. The mesocoms were subjected to eight different treatments, including two levels of light availability at the forest floor, nitrogen addition and climate warming. The community response will be monitored at least until the end of 2018. Besides, additional studies focusing on tree recruitment, litter decomposition and nutrient uptake will be performed in the mesocoms to get a better understanding of the consequences of herb layer-mediated effects of the various global change drivers on these important ecosystem processes.
Finally, insights from (1) to (3) are currently being used to develop and parameterize a process-based model to predict changes of herb layer communities in temperate forests. The model merges concepts of grassland models, yield-based crop models and forest gap models and we plan to evaluate changes in herb layer composition in terms of biodiversity, ecosystem functioning and ecosystem service provisioning.

Contact

Ilona Stoffels, (European Research Advisor)
Tel.: +3292643633
Fax: +3292643583
E-mail
Record Number: 195429 / Last updated on: 2017-03-13