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Maintenance of species diversity and the stability of ecosystem functioning

Periodic Reporting for period 1 - BioFUNC (Maintenance of species diversity and the stability of ecosystem functioning)

Reporting period: 2016-06-15 to 2018-06-14

BioFUNC arose from the need to provide sustainable ecosystems services to the society while conserving biodiversity. This is still a particular societal major challenge as current rates of biodiversity is negatively affecting the deliver of several ecosystem services critical to human welfare such as food production, carbon storage and nutrient accumulation. In order to do so, this project identified that there was a gap of knowledge between the known mechanisms promoting the function of ecological communities and the mechanisms determining biodiversity maintenance. More importantly, the project presented an specific methodology and its application to direct experimentation to bring both fields in order to obtain an emerging framework that will allow distinguishing to what extent services we obtain from nature are stable or transient, and which are the change in magnitude of these services due to the local extinction of species. Overall, the main objective of BioFUNC was to establish for the first time mechanistic linkages between the drivers of species coexistence and the processes maintaining high and stable ecosystem functioning. This objective has required unifying two longstanding bodies of research that unfortunately were not previously combined. These are on one hand the importance of species characteristics, climatic variability and spatial heterogeneity for the maintenance of species diversity and on the other hand the consequences of variation in abiotic (climate and soil) and biotic (community composition, species characteristics and their relative abundances) factors for providing stable ecosystem functions.
Achieving the main aim of BioFUNC has required to develop novel methodological advances in coexistence theory that have been integrated with mathematical models of annual organisms describing species population dynamics. Then, BioFUNC has applied these novel toolboxes to detailed observational and experimental studies simulating different climate change regimes. Specifically, one experiment working with 10 plant species has served to prove experimentally for the first time the complex relationship between the complementarity and selection effect determining the functioning of ecological communities and the stabilizing niche and fitness differences determining the maintenance of species diversity. BioFUNC has shown that more stable communities (i.e. communities in which the amount of niche differences overcome greater fitness differences) are able to provide more functioning in terms of biomass production, and this relationship is stronger under drier conditions. Yet, these specific linkages are loss when there are considered other functions that involves the action of other trophic levels such as the case of liter decomposition or nutrient cycling. The same experiment has also served to understand how the network of competitive interaction that plant species establish when competing together determine the amount of biodiversity within ecological communities. Specifically, combining data obtained directly from the experiments with tools from network theory served to show that the amount of intransitive competition (e.g. rock-scissors-paper dynamics) is not related with the amount of biodiversity maintained, even more, drier conditions results of higher prevalence of intransitive competition within networks but reduced the overall biodiversity maintained. The other main experiment conducted within BioFUNC framework has served to understand under natural conditions the role of below ground interactions and above ground interactions due to floral visitors on the degree of coexistence of plant communities. This project has shown that both types of interactions maintain species diversity in heterogeneous landscapes, floral visitors do so by increase the likelihood of coexistence at local scale and soil conditions (soil salinity) promote diversity by changing the identity of the superior competitor across locations. BioFUNC has also made significant progress in the theoretical side of species coexistence proposing a detailed methodology to study complex systems in which different type of species interactions are considered such as competition, facilitation, parasitism, predation and mutualism. Overall, this experimental and theoretical work has allowed to increase the scientific impact of BioFUNC by presented main results to some of the most relevant international meetings in ecology (Ecological Society of America, British Ecological Society, MEDECOS), and by publishing them in leading journal of multidisciplinary and ecology sciences such as Trends in Ecology and Evolution, Ecology Letters, and Journal of Ecology. Particular attention has been also given to outreaching activities. BioFUNC has presented main results during the last three years at the European Researchers’ Night, has visited several high-schools and performed a video for divulgation purposes both in English and Spanish languages (https://www.youtube.com/channel/UCf7hBC5ChUKEGeJiKKfR1wQ).
After two years of hard work, BioFUNC officially finished on July 12th 2018 but undoubtedly with so heavy load of fieldwork much analyses and writing are still on progress. Thanks to the activities developed in BioFUNC, the person who has conducted almost all activities within BioFUNC (Dr. Oscar Godoy) has reached a tenure track position at a Spanish University (Ramón y Cajal program) which allow to continue working on scientific reports to aim publishing them in leading international journal of multidisciplinary, ecology and plant sciences. Experiences obtained from BioFUNC are now entering into a more applied phase. Thanks to understanding the mechanistic role of the determinants of species interactions and the provision of biomass, Dr. Godoy has proposed to participate in a PRIMA (Partnership for Research and Innovation in the Mediterranean Area) call to applied obtained knowledge to increase biomass production of the main cereal crops used in the Mediterranean basin without increase the money spent for fertilizers of watering, and therefore reducing potential environmental problems. This is a challenging task because involve scaling detailed common garden experiments to much larger areas but the potential benefits are worth trying specially for rural economies. Another important result with societal implications is that the project is increasing our understanding of how biodiversity of several taxa (plant, pollinators, herbivores) is maintained in Mediterranean grasslands, which are among the most diverse ecosystems in Europe despite being consistently neglected from National and International protection programs. Put in value the importance of these ecosystems and the diversity it harbors is critical to show to the general public the rich natural patrimony of these European Ecosystems.