Diversity and functional redundancy (e.g. bloom time, host plant, drought resistance, etc) is something I think about a lot. It’s often dealt with as one function at a time, but this paper gives a broader perspective; it puts together multiple layers. When we account for multiple functions, places, years, and environmental changes, however, many more species contribute to maintaining ecosystem functioning than a narrow assessment would reveal.

The central finding was that 84% of the 147 plant species promoted ecosystem functioning in at least one context. However, the species that mattered in one situation were not necessarily the same species that mattered in another. A plant that contributed to ecosystem functioning in one year, for example, might not be among the most important species in another year or location. Likewise, the species supporting one ecological function were not necessarily the ones supporting several functions simultaneously.

As the researchers considered more situations, the number of species contributing to ecosystem functioning increased. A plant community may appear to function just as well with fewer species when we consider only one ecological function or when we evaluate a plant community based on a single ecological function, we may underestimate the contributions of some species.  But when we account for multiple functions, locations, years, and changing conditions, the contributions of additional species become more apparent.

1. A species’ value may not be apparent all the time. A plant that contributes little to a measured function under current conditions may become more important under different environmental conditions or in a different year.

2. Species that seem interchangeable may not be interchangeable across contexts. Two plants might contribute similarly to one function, such as productivity, without contributing equally to other functions or responding similarly to environmental change

3. Diversity provides options and resilience. Maintaining a broader range of species increases the likelihood that some will continue contributing to ecosystem functioning as conditions change. This is consistent with the ecological insurance concept discussed in biodiversity research.

4. Measuring one function gives an incomplete picture. Productivity or plant cover alone cannot tell us how well an ecosystem supports multiple ecological processes. The species that matter for one outcome may differ from those important for others.