Grassland Biodiversity Indicators in the Western Swiss Plateau – Modelling Possible Impacts of Climate Vs
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Grassland biodiversity indicators in the Western Swiss Plateau – Modelling possible impacts of climate vs. management changes LUCA BUSSANI Master’s Thesis 2017 Oeschger Centre for Climate Change Research (OCCR) University of Bern Supervisor: Prof. Dr. ANNELIE HOLZKÄMPER Agroscope Reckenholz Oeschger Centre for Climate Change Research (OCCR) Co-Supervisor: Prof. Dr. ERIC ALLEN IPS University of Bern Oeschger Centre for Climate Change Research (OCCR) Advisors: Nina Zarineh and Felix Herzog (Agroscope) Anne Jungandreas (UFZ Leipzig) Abstract Agricultural intensification and climate change are among the main causes for current biodiversity losses. The effects of environmental changes on species richness may be assessed with statistical modelling approaches. In this study, a two-part hurdle model was implemented to predict present and future distribution patterns of plant richness in grasslands within the catchment of the Broye river, an intensively managed area in the Western Swiss Plateau. This approach allowed identifying environmental factors affecting significantly the presence and/or abundance of selected species. Mean winter temperatures and the intensity of pasture management were very significant drivers over all groups of species. These predictors were thus used to define future climatic and land use scenarios. An extensification of grasslands (20% of pastures area from intensive to extensive) under warmer conditions (+ 2° C in mean winter temperature) resulted to be a particularly profitable strategy for the highland of the Broye region in terms of species richness. Moreover, we conclude that the incorporation of land use data and stakeholder-based scenarios in species richness modelling approaches could substantially improve the identification and implementation of future biodiversity conservation areas. i Table of Contents Abstract ...................................................................................................................................... i List of Figures .......................................................................................................................... iv List of Tables ........................................................................................................................... iv 1. Introduction .......................................................................................................................... 1 1.1 Research Motivation ........................................................................................................ 1 1.2 TALE Project ................................................................................................................... 2 1.3 Biodiversity Indicators ..................................................................................................... 3 1.4 Biodiversity Modelling .................................................................................................... 4 1.5 Project Aim and Research Questions ............................................................................... 5 1.6 Project Design .................................................................................................................. 5 2. Theoretical Background ...................................................................................................... 7 2.1 Modelling Approaches ..................................................................................................... 7 2.2 Regression Models for Count Data .................................................................................. 8 2.2.1 Generalized Linear Models ....................................................................................... 8 2.2.1.1 Poisson ................................................................................................................ 9 2.2.1.2 Quasi-Poisson ..................................................................................................... 9 2.2.1.3 Negative Binomial .............................................................................................. 9 2.2.2 Zero-Inflated Models ............................................................................................... 10 2.2.2.1 Mixture Models: ZIP and ZINB ....................................................................... 10 2.2.2.2 Two-Part Models: Hurdle ................................................................................. 11 3 Materials and Methods ....................................................................................................... 12 3.1 Study Site ....................................................................................................................... 12 3.2 Selection of Biodiversity Indicators ............................................................................... 13 3.3 Selection of Predictors ................................................................................................... 15 3.4 Data Processing .............................................................................................................. 17 3.5 Model Specification ....................................................................................................... 20 3.6 Model Validation............................................................................................................ 22 3.7 Future Scenarios ............................................................................................................. 23 4 Results .................................................................................................................................. 25 4.1 Model Performance ........................................................................................................ 25 4.2 Model Predictions .......................................................................................................... 27 4.2.1 Present Distribution ................................................................................................. 27 4.2.1.1 Guild 1 - Moist and Nutrients Poor................................................................... 29 ii 4.2.1.2 Guild 2 – Moist and Nutrients Rich .................................................................. 29 4.2.1.3 Guild 4 – Dry and Nutrients Poor ..................................................................... 30 4.2.1.4 Guild 5 – Dry and Nutrients Rich ..................................................................... 31 4.2.1.5 Guild 7 – Fresh and Nutrients Poor .................................................................. 31 4.2.1.6 Absolute Sum .................................................................................................... 32 4.2.1.7 Standardized model predictions ........................................................................ 33 4.2.1.8 Comparison between model prediction and observation .................................. 34 4.2.2 Future Predictions .................................................................................................... 35 4.2.2.1 Climate Scenarios ............................................................................................. 36 4.2.2.2 Land Use Scenarios........................................................................................... 37 4.2.2.3 Combined Scenario ........................................................................................... 38 5 Discussion............................................................................................................................. 40 6 Conclusions and Outlook ................................................................................................... 47 6.1 Summary and Conclusion .............................................................................................. 47 6.2 Outlook ........................................................................................................................... 48 References ............................................................................................................................... 50 Appendix ................................................................................................................................. 56 Annex 1............................................................................................................................. 56 Annex 2............................................................................................................................. 57 Annex 3............................................................................................................................. 58 iii List of Figures Figure 1: Biodiversity indicators in relation to agriculture.................................. 4 Figure 2: Broye catchment ................................................................................. 12 Figure 3: Observation data ................................................................................. 14 Figure 4: Resources, direct and indirect environmental gradients .................... 16 Figure 5: Raster with 1x1km cells ..................................................................... 19 Figure 6: Histogram of species abundance ........................................................ 21 Figure 7: Emissions and temperature scenarios CH2011 .................................. 23 Figure 8: Species richness predictions for the single guilds (1, 2, 4, 5, 7) ........ 28 Figure 9: Absolute map .....................................................................................