Objective 5: Assessment of links between ecosystem functioning and diversity of plants and mammals and, and long-term historical constraints hereon:

Studies on biodiversity effects on ecosystem functioning has primarily been small-scale experimental studies of simplified ecosystems, making it a key question whether their findings can be up-scaled to complex real-world ecosystems and large expanses. As a result, large-scale comparative studies have been highlighted as a key promising avenue for future progress.

The HISTFUNC project will provide macroecological analyses of the links between functional diversity of plants and mammals and ecosystem functioning, a central part of the ‘historical constraints’ hypothesis, as well as of broad relevance for ecology. We will for the first time assess the relative roles played by horizontal and vertical functional diversity as well as their interaction for real-world ecosystems on a large scale. The importance of consumer diversity has been highlighted as an understudied area in biodiversity/ecosystem functioning research. We will furthermore assess if other aspects of diversity have supplementary links to ecosystem functioning, notably species diversity per se and phylogenetic diversity, e.g., reflecting pure diversity effects such as protection from pests and pathogens. Data from the previous components will be integrated to allow these analyses.

Impact: This assessment of large-scale links between functional diversity and ecosystem functioning answers a call for large-scale studies of this relation. Understanding this link furthermore requires integrating functional diversity within and across trophic levels – this objective represents an important step forward by providing the first such integrated assessment at large scales. An even more novel aspect of this proposal is the assessment of historical influences on the diversity-functioning link – such effects are expected on theoretical grounds, but have not received any attention in the literature.