Skip to content

Interactions between plants and soil are responsible for providing numerous ecosystem services from forests, including carbon sequestration, protection from erosion, improved soil fertility and stabilization of contaminants.

In the XXV World Congress of the IUFRO (International Union of Forest Research Organizations), held at Curitiba, Brasil from September 29th to October 5th, a scientific session (number E8,d,g) was devoted to the topic “Plant-soil interactions in forests”.

1) Different tree species affect differently to soil properties. For example, soil pH underneath pines (Pinus pinea) and holm oaks (Quercus ilex) was lower than under other five tree species in the same study area. These soil pH differences have relevant consequences for the mobility of trace elements and their uptake by trees (Madejón et al., 2018, Catena 166: 34-43).

2) Soil mycobiota differed in diversity and composition under wild olive (Olea europaea), stone pine (Pinus pinea) and white poplar (Populus alba), and with adjacent treeless sites. The afforestation represented 100% increase of soil fungal diversity, compared with the remediated zones (only with pastures). A total of 6535 OTUs (operational taxonomic units) were estimated as the gamma diversity of soil fungi in the study area (Gil-Martínez et al., in preparation).

The functional diversity of soil fungi (according to the FUNGuild data base) was represented by three main functional groups: saprotrophs (68% of OTUs), pathogens/parasites (18%) and mycorrhizal fungi (12%). Within the mycorrhizal fungi group, arbuscular fungi were associated to soil samples under wild olive and treeless pastures, while ectomycorrhizal fungi were abundant in soil under poplar and pine.

3) The case of mycorrhizal fungi is relevant because of their symbiotic relations with trees. Ectomycorrhizal fungi communities were studied by sampling root tips of 40 holm oaks (Q. ilex) distributed along four sites of the Guadiamar Green Corridor. A total of 55 OTUs were identified, with average of 3.8 fungal species per tree. Soil properties influencing primarily the composition of mycorrhizal fungal communities were total soil carbon, and the concentration of Ca, Cu, Ni and Zn (López-García et al., 2018, Soil Biol Biochem 121: 202-211).

In turn, the composition of mycorrhizal fungal communities affected significantly the accumulation of P in leaves, and the transfer rate of Zn from soil to root (Gil-Martínez et al., 2018, Front Plant Sci : 1682).

4) Soil fungi have a relevant role degrading organic matter and cycling nutrients, by the action of extracellular enzymes. We have found that beta-glucosidase activity (enzyme contributing to cellulose degradation) was much higher in the soil under poplar and pines than in soil under wild olive or in pastures. A feedback process can be inferred, by which tree species influence composition and abundance of soil fungi, and the rate of enzyme activity, which in turn promote organic matter decomposition and release of nutrients, which are up-taken by trees (Gil-Martínez et al., 2018, Proceed. Mine Closure 2018, Leipzig, pp. 636-647).

In summary, there are complex interactions between the aboveground and belowground subsystems of the forest ecosystem. Several examples of tree-microbiota-soil feedback processes have been studied in the Guadiamar Green Corridor. Metal uptake by trees is influenced by soil pH, which in turn can be modified by litter decomposition and root exudates. The composition and diversity of soil fungi are affected by tree species identity; on the other hand, mycorrhizal fungal communities influence some tree processes, like leaf P concentration, and Zn transfer from soil to root. Trees influence on soil enzyme activities, which in turn affect nutrient cycling and their uptake by trees.

A pdf copy of the presentation slides can be consulted in Digital CSIC.

The Iberian Ecological Society SIBECOL has just been established to gather professional scientist from Portugal and Spain from all ecology areas: theoretical, terrestrial, marine and continental waters. Its main aim is promoting ecology and to give visibility to scientific works in all these fields.

To celebrate the establishment of the society and to share the scientific progress in ecology, last 4th -7th of February the First SIBECOL Congress, as well as the XIV AEET Meeting, were celebrated. The venue selected was the Faculty of Biology at the University of Barcelona (Spain).

This congress was celebrated in an emblematic time and place due to the commemoration, this year 2019, of the centenary of Professor Ramon Margalef. Margalef became one of the most relevant ecologist of the XX century and the first professor of Ecology in Spain at the University of Barcelona, where all the Iberian ecologist had the opportunity to meet.

INTARSU Project did not want to miss this important event for ecology and we had the opportunity of presenting our last study in a poster titled: “Phytostabilisation of trace elements with different tree species revealed a species-specific effect on soil functioning”. This work has been possible thanks to the collaboration between researchers from IRNAS-CSIC, University of Sevilla and University of Reading (United Kingdom). The poster was presented in the Thematic Session 14 “Organisms and ecosystem responses to global change in soils and sediments”, organized by the Group of Plant-Soil Interactions of AEET.

In this study, we presented the effects of different tree species (white poplar, wild olive and stone pine) on biotic and abiotic soil properties. The study area, known as Guadiamar Green Corridor (Seville), suffered in 1998 a serious contamination due to Aznalcóllar mine-spill. After a remediation plan in the whole affected area, different tree and shrubs species were planted, and 15 years after these trees have generated soil changes. In relation to soil nutrients, we have found that the tree coverage has increased fertility in soils underneath compared to soils covered by herbaceous plants. Among the studied species, white poplar trees have helped to neutralize soil pH; however, stone pine trees have acidified the soil which is undesirable as acidity increases soil trace element availability. Soil microbial activity presented differences among tree species and we found that enzyme activities with an important role in C, N and P cycles were highly dependent on soil pH. To summarise, we have found a tree species effect on abiotic and biotic soil properties with direct consequences on soil functioning.

Gil-Martínez, Marta; Domínguez, María Teresa; Navarro-Fernández, Carmen María; Tibbett, Mark; Marañón, Teodoro (2019). Phytostabilisation of trace elements with different tree species revealed a species-specific effect on soil functioning. In: Abstract book. 1st Meeting of the Iberian Ecological Society & XIV AEET Meeting. Ecology: an integrative science in the Anthropocene. February 4-7, 2019, Barcelona (Spain), page 269. AEET, Madrid, DOI: 10.7818/SIBECOLandAEETmeeting.2019.