Our Science article “Plant Species Richness and Ecosystem Multifunctionality in Global Drylands” has been evaluated by three members of Faculty of 1000. Below we provide a copy of the evaluations, which can be found here.
Jordi Bascompte, Estación Biológica de Doñana, CSIC, Spain.
This paper is the result of an international cooperative project showing that ecosystem multifunctionality is strongly related to species richness in drylands.
We already knew that species richness has important implications for ecosystem services. Specifically, richer communities have been found to be more productive and stable. This knowledge, however, has been obtained through controlled, small-scale experiments where plant species were combined in appropriate ways, mainly in North America and Europe. This paper advances the research on ecosystem services in three important ways. First, it considers naturally occurring plant communities. Second, it addresses several dimensions of ecosystem function related to the cycling and storage of Carbon. Finally, it expands a large geographic range, involving 224 ecosystems from all continents but Antarctica. On top of that, this work focuses on one ecosystem type of relevance given its extension and importance for the human global population. Using different statistical approaches, the authors show that species richness is strongly related to multifunctionality. These results make a strong basis for preserving biodiversity world-wide.
There is now a large body of work concerned with the relationship between biodiversity and ecosystem functioning but comparatively little regarding this relationship at the global scale. In this paper, Maestre and co-workers addressed this by investigating correlations between species richness and ecosystem multifunctionality indices in a global study of drylands, comprising 224 sites.
The authors selected multiple regression models based on the quality of their fit and parsimony: those deemed the best (based on the model AIC) typically explained 55 per cent of the variation in ecosystem multifunctionality and always contained species richness. As such, species richness was found to be globally important as a driver of ecosystem multifunctionality, in addition to mean annual temperature and soil texture. Although this association was correlative, the strength of this study lies in its highlighting of the importance of species richness at a global-scale; it sets the stage for further investigation of the biodiversity-ecosystem function relationship in other biomes and extensions into the domain of functional diversity.
Georgina Mace, Imperial College, UK.
This paper uses a global dataset to empirically assess the relationship between biodiversity and ecosystem functioning. It is one of the first papers to consider multiple ecosystem functions concurrently, and it highlights the importance of the effect of complexity on biodiversity loss and ecosystem functioning under environmental and climatic change. There are a number of studies suggesting that biodiversity loss may impair ecosystem functioning. However, most of these look at single ecosystems functions in isolation and utilise controlled, small-scale experiments. This study assesses the empirical relationship between plant species richness and abiotic factors to multi-functionality in natural drylands, using a global dataset. Through the use of non-spatial and spatial regression models, the authors evaluate both the direct relationship between species richness and multi-functionality and whether the observed effects of species richness are important compared to those of abiotic factors. The results show consistent effects of species richness on multi-functionality over and above those of climate and abiotic factors, highlighting the importance of plant biodiversity as a driver of multi-functionality in drylands.
The strength and novelty of this paper lies in the fact that it attempts, perhaps for the first time, to consider the interactions between multiple ecosystem functions concurrently. The use of collected rather than simulated ecological and biophysical data at such a large scale is also unusual and strengthens the conclusion that correlation between biodiversity and multi-functionality may be a general pattern in nature that reflects a cause-and-effect linkage. However, this paper also highlights the need to consistently consider the underlying, and as yet often unknown, complexities driving ecosystem functioning. The authors discuss the hypothesis that complementarity in the use of resources, such as water, may account for correlations between species richness and multi-functionality as opposed to increased net primary production (NPP). They also point out that climate change may have both positive and negative effects on biodiversity and ecosystem functioning, and that the overall outcome may be difficult to predict. This study illustrates the need to consider multiple ecosystem functions simultaneously, in order to account for the underlying complex biophysical and ecological interactions taking place in natural ecosystems. Without doing so, it is very difficult to draw strong conclusions regarding the possible effects of climate change or land-use change on biodiversity and ecosystem functioning and to plan for these changes appropriately.