Recently, it has been assumed that functional aspects of biodiversity provide a more mechanistic explanation of the interaction between plant species and ecosystem functions. Plant communities control ecosystem functions (EFs) involved in biogeochemical cycles such as aboveground net primary productivity (ANPP) through Plant Functional Traits (PFTs) i.e., characters measurable at the individual level, which indirectly affect plant fitness. The type, range and relative abundance of PFTs throughout the plant community defines the Plant Functional Diversity (PFD). Two not mutually exclusive hypotheses (Dominance and Complementarity hypotheses) explain the mechanisms underlying the relationship between PFD and EFs. Nevertheless, their relative importance in explaining EFs remains unclear, especially for complex and highly biodiverse systems such as the Mediterranean shrublands. On the other hand, biodiversity plays a strategic role in determining the ecosystem resilience to disturbance. This project aims at exploring the functional pathways linking FPD, EFs, disturbance factors and ecosystem resilience by answering the following questions: ii) how does PFD affect EFs, and in particular ANPP in the Mediterranean shrublands; ii) can PFD affect the resilience of ANPP after a disturbance event such as wildfire? If so, is Dominance or Complementary hypothesis more suitable to explain the resilience of the ANPP in Mediterranean shrublands? Answering these questions will allow to: i) promote advancements in plant trait research to better understand the PFTs assemblage rules in defining trait distribution and variability; ii) improve knowledge on a currently open research field such as the role of PFD in driving ecosystem functions; iii) to define new and more efficient strategies, not only for biodiversity conservation but also for ecosystem function recovery.
An innovative aspect of this project is to explore a functional pathway linking plant biodiversity, disturbance factors, and ecosystem functions in attempting to extend an experimental approach developed for relatively simplified systems (i.e. boreal and temperate grasslands) to Mediterranean shrublands, characterized by a higher structural complexity. This complexity translates into a no linear multivariate relationship among all the involved factors, meaning that Mediterranean shrublands offer a wider range of conditions for better elucidating the mechanisms by which plant diversity controls ecosystem functions.
Moreover, considering the role of wildfire in shaping PTFs in the Mediterranean ecosystems, the choice to focus on wildfire as a disturbance factor makes the project even more challenging also considering that over the last decades Mediterranean ecosystems are experiencing a major shift in fire regime with relevant changes in fire frequency and spatial patterns as well as an increased risk of the mega-fires occurrence [1-3]. The possible causes of these changes have directly or indirectly an anthropic origin such as agropastoral activities as well as abandonment of agricultural lands, increase of human ignitions for accidental causes or for criminal intents [1,2], the exacerbation of climate conditions including temperature increases, drought, and prolonged heat waves [4]. Moreover, in such a context characterized by a high anthropic disturbance, expanding knowledge on the resilience capacity is of critical importance for tackling important issues related to the functioning of the ecosystems. Changes in disturbance frequency and intensity can increase the uncertainty about how ecosystems will respond to new conditions. Such a type of information helps for predicting to what extent EFs will be impacted by disturbance, and therefore for promoting efficient land management strategies to maintain the services related to EFs. Furthermore, having a thorough look at aboveground and belowground ecosystem dynamics with analyses of the biological soil quality patterns of the study areas has never been done in Italy, and will provide further support to PFD analysis and modelling.
Overall, the achievement of the project objectives will confer to the project a high potential in:
i) promoting advancements in plant trait research to better understand the PFTs assemblage rules in defining trait distribution and variability within Mediterranean shrubland communities;
ii) improving knowledge on two currently open fields for future research: the role of functional plant diversity in promoting ecosystem functions as well as the role of the interaction between plant communities and soil biodiversity to drive EFs variation;
iii) defining new and more efficient strategies, not only for biodiversity but also for ecosystem function resilience.
References
[1] Pausas 2004 Clim Change 63:337¿350
[2] Turco et al. 2018 Nat Commun 9: 3821
[3] Pausas & Fernández-Muñoz 2012 Clim Change 110:215¿226
[4] Pausas & Paula 2012 Glob. Ecol. Biogeogr 21:1074-1082