Landscape diversity is positively linked to landscape functioning

Jacqueline Oehri, Gabriela Schaepman-Strub and Pascal A. Niklaus, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland, Jacqueline Oehri, Bernhard Schmid, Gabriela Schaepman-Strub and Pascal A. Niklaus, University Research Priorty Programme Global Change and Biodiversity (URPP GCB), University of Zurich, Zurich, Switzerland, Bernhard Schmid, RSL, Department of Geography, University of Zurich, Zurich, Switzerland

Background/Question/Methods
Past biodiversity-ecosystem functioning (B-EF) research has shown that species richness promotes ecosystem functions including productivity and stability in small experimental plots. Studies reporting positive species richness effects in non-experimental ecosystems are accumulating. This suggests that B-EF relationships are generalizable from experimental to “real-world” conditions at larger spatial scales.
However, it is still unclear if B-EF relationships also hold at higher levels of hierarchical organization and hence, if the diversity of ecosystem types in entire landscapes influences relevant landscape functions, including vegetation productivity, climatic forcing and the temporal stability of these.
Here we combine remote-sensing data covering large scales of space and time with statistical methods inspired from B-EF experiments to assess landscape diversity-landscape functioning relationships (LD-LF) across the whole area of Switzerland (Central Europe).
Specifically, we relate land-cover type richness in 4974 landscape plots 6.25 and 25 ha in size to a 17-year time series of satellite-sensed landscape functioning including vegetation productivity, stability and climate-relevant albedo (MODIS EVI and Albedo products). We use a quasi-experimental design, where we select landscape plots so that landscape richness as explanatory variable is not confounded by the presence of particular land-cover types and environmental conditions.
Results/Conclusions
We show that landscape-level mean and inter-annual stability of yearly vegetation productivity increases with land-cover type richness; independent of the size of landscape plots investigated. Additionally, summer near-infrared albedo is higher in mixed than in single land-cover type landscape plots. Effect sizes for the different landscape functions are as large as those reported from typical B-EF-experiments.
These results suggest that similar to species richness, landscape richness promotes landscape-level functioning. Landscape richness affects landscape functioning not only via biogeochemical (productivity) but also biogeophysical (albedo) pathways.
We contend that increasing and protecting the diversity of ecosystem types could support maintaining vegetation productivity and climate stability in complex real-world landscapes at spatial, temporal and organizational scales relevant for conservation management.