COS 132-7
Biodiversity and ecosystem function in the real world: The German Biodiversity Exploratories
Concerns over biodiversity loss have led to the proliferation of research examining the relationship between biodiversity and ecosystem function over the last 20 years. Experimental results from this work have consistently shown that ecosystems with a high plant diversity sustain higher levels of multiple ecosystem functions and services, a property known as multifunctionality. What is less clear is how biodiversity relates to multifunctionality in real-world ecosystems where most biodiversity loss is caused by global change drivers that also directly affect ecosystem services. Here we addressed this knowledge gap by using data from the large-scale and long-term Biodiversity Exploratories in Germany. 14 ecosystem service measures from 150 grassland sites in three regions of Germany were used to generate multifunctionality measures and these were related to land use intensity and plant species richness in a structural equations modelling framework.
Results/Conclusions
Our results show that land use intensification alters ecosystem multifunctionality both directly and via indirect effects on reduced biodiversity, and that both pathways are important. We also show that the direction and strength of biodiversity effects differs depending upon land use objectives. If services related to food production are prioritised, land-use intensification directly increases multifunctionality and reduces biodiversity, with positive consequences for functioning. In contrast, if supporting and cultural ecosystem services are the priority, then direct land-use intensification effects are negative and biodiversity loss reduces ecosystem multifunctionality. The strength of these effects also varied between regions. In one region intensification increased function but reduced biodiversity, with strong negative effects on multifunctionality. In another region biodiversity loss was associated with increases in most ecosystem services, probably because the species lost possessed traits associated with slow ecosystem process rates.
These results indicate that biodiversity drives ecosystem multifunctionality in the real-world agricultural grasslands but also that the real-world relationship between biodiversity and ecosystem services is variable and significantly more complex than that seen in experiments. Our findings also highlight the need to examine the functional impacts of biodiversity loss within the context of factors with which it is associated; direct effects of global change drivers and directional changes to functional composition.