Merging community and ecosystem ecology via litter decomposition
We like to do science using interdisciplinary approaches because we think this is the best way to face the humanity’s greatest challenges. Combining community and ecosystem ecology aspects we can answer global ecological questions that matter for ecosystem management. The decomposition of leaf and root litter is heavily influenced by plant traits and soil (microbes and fauna) communities, and it is crucial to the regulation of soil C and N dynamics. We have been looking at the biotic and abiotic drivers of litter decomposition in aquatic and terrestrial environments, and across temporal stages of litter decay. This research has been funded by the Fulbright Commission and a Marie Skłodowska-Curie Action awarded to Pablo García-Palacios in collaboration with Diana Wall (Colorado State University) and Stephan Hättenschwiler (CNRS). Currently, we are testing the linkages between plant community assembly, soil microbes and ecosystem functioning using plant trait distributions. With funds from the British Ecological Society (SR17\1297, PI Pablo García-Palacios), we are addressing such relationships across six global biomes and 90 litter
species in collaboration with Nicolas Gross (INRA) and Yoann Le Bagousse-Pinguet (CNRS).
Nowadays, we face the major challenge of feeding nine billion people by 2050. At the same time, synthetic fertilizers and pesticides are being restricted because of their major environmental impacts. This situation requires that approaches proved useful during the
Green Revolution (farming practices and plant breeding) transition towards more sustainable strategies capable of increasing crop production, its stability over time and its resistance to climate change. Agroecology and ecological intensification advocate doing so by optimizing ecosystem services key for crop yield, such as soil C sequestration and soil N retention, while decreasing external inputs. We are involved in two European projects (BiodivERsA / FACCE) looking at the effects of organic farming and crop diversity on crop yield and ecosystem multifunctionality in European arable lands (Eco-Serve and Digging Deeper). We also collaborate with agricultural research institutions in Spain that mantain long-term (> 20 years) crop diversity and tillage trials (INIA, IMIDRA, ICA).
Drylands are regions with an Aridity Index below 0.65, and represent about 45% of Earth’s land surface. The increases in aridity that are forecasted with climate change in drylands may jeopardize the provision of ecosystem services that are key to sustain over 38% of the world's human population. We are part of the Dryland Ecology & Global Change Lab led by Fernando Maestre at URJC, where we are involved in two exciting projects funded by the European Research Council (BIOCOM and BIODESERT). With research funds from a Juan de la Cierva-Incorporación contract awarded to Pablo García-Palacios (IJCI-2014-20058), we are investigating the impacts of climate change on biosphere-atmosphere feedbacks and ecosystem stability. Firstly, we address the mechanisms behind the long-term effects of warming on soil respiration (examples here and here; check out our thematic session at 2018 BES annual meeting in UK). Secondly, we study how climate mediates the relationships between plant (taxonomical and functional) diversity and ecosystem stability across the globe (new paper published in PNAS! check out this cool video in spanish).
Ecosystem responses to plant domestication
Beyond driving the effects of farming practices, plant traits and soil microbes may be directly manipulated via plant breeding to impact key ecosystem services for crop yield. So far, plant
breeding programs have seek to enhance production by focusing on traits such as seed quantity or pest resistance. We argue that plant breeding should focus on traits with positive effects on soil C sequestration, soil N retention, and yield resistance to climate change. In this line, the comparison of domesticated (commercial varieties) vs. old (wild progenitors) crop genotypes is a meaningful framework to guide ecosystem services-oriented plant breeding. These particular genotypes represent two plant resource-use strategies (slow vs. fast-growing species, respectively) with conspicuous effects on soil C and N cycling. In collaboration with Rubén Milla, Manuel Delgado-Baquerizo and Silvia Matesanz we are looking at the microbiome, litter decomposition, soil functioning and diversity effects across > 20 domesticated-wild progenitors pairs from important staple crops such as cereals (C4 and C3), legumes, and forbs.
A new PhD student starting soon!
Systematic reviews and meta-analysis
Scientific literature syntheses have experienced a major change in the last 20 years, from purely descriptive summaries of (part of) the available literature, to systematic searching using online databases (e.g. Web of Knowledge), data extraction from articles and complex analytical tools (e.g. meta-regressions). We love meta-analyses. They allow us to explore consistent patterns across large spatial scales and environmental conditions. We actually believe that meta-analyses should constitute a first chapter in any PhD thesis. We particularly like to combine meta-analytical tools with structural equation modeling, to disentangle the relative importance of climatic, soil, plant and methodological variables as drivers of the effect size of a particular treatment. We have conducted meta-analyses addressing the effects of soil fauna on litter decomposition, the links between the responses of soil microbes and ecosystem functioning to global change, the effects of organic farming on soil C accumulation, the responses of primary productivity to precipitation extremes, or the responses of soil enzymes to experimental warming.