Periodic Reporting for period 1 - CCPaMe (Direct and indirect effects of Climate Change on biotic communities and exotic Pathogens in mixed Mediterranean forests)
Periodo di rendicontazione: 2017-01-01 al 2018-12-31
We have conducted a field experiment of climate change simulation in an infested mixed Mediterranean forest located in Los Alcornocales Natural Park (Cádiz, southern Spain), as well as, several in planta experiments under controlled conditions to determine the interactive effects of climate change and woody plant community on the exotic pathogen Phytophthora cinnamomi. In particular, CCPaMe have been focused on the variation of this pathogen population density in wild forests mediated by seasons and tree species coexistence. As main results of these experiments, spring was detected as the most favorable season for P. cinnamomi inoculum viability. Additionally, CCPaMe described to Olea euopaea var. sylvestris as a new host of P. cinnamomi which susceptibility might be age-related. On the most important research findings is that P. cinnamomi may act as facultative homotallic under the influence of Quercus canariensis and Olea euopaea var. sylvestris, two of the principal trees integrant of plant community of mixed Mediterranean forests. Moreover, tree species coexistence and climate change did not decrease the severity of root rot caused by P. cinnamomi.
On the other hand, by another field experiment of climate change simulation in three un-infested rangeland ecosystems located in areas of high risk of P. cinnamomi introduction, we determine the variation of P. cinnamomi infectivity mediated by soil properties and microbiota composition during the two years of Action. CCPaMe results showed that at the end of summer soil properties are more favorable for P. cinnamomi infectivity. Consequently, the preventive action to avoid P. cinnamomi outbreak should be focused on this season. Additionally, the effect of climate change on P. cinnamomi infectivity, although it only differs to the control conditions during summer, is high linked to annual precipitation range.
Some of the main results of CCPaMe have already been presented in four international (2) and national (2) meetings. CCPaMe has also been focused on outreaching activities, actively participating at the European Researchers’ Night, ‘Caffe with Science’ centering on science dissemination to high schools’ students, general public speeches to celebrate the Environmental Day (June 5th) and by a website. Additionally, CCPaMe has served to the researcher to supervise three Master students and two undergraduate students.
On the other hand, it is the first time that an infrastructure of climate change simulation set-up in a forest is successfully used to evaluate the consequences of climate change on invasive pathogens dynamic. CCPaMe has generated valuable knowledge on plant performance and long-term persistence of mixed forests under the simultaneously influence of climate change and P. cinnamomi. These findings contrast with prior hypotheses of synergistic interactions between both driving factors.
One of our major contributions to the state of the art has been the establishment of the annual variation of sporangia production of P. cinnamomi in ecosystems favorable to root disease development. We concluded that control action to prevent pathogen’s outbreak, should be focused on reducing soil appropriateness to sporangia and zoospore production mainly during summer. On the other hand, the interaction of climate change with P. cinnamomi infectivity is directly linked to the annual precipitation range. The mechanisms by which these patterns occur are not clear and needs further exploration, including the completion of soil microbiota analyses which are currently carrying out.
These results allow the possibility to expand this kind of studies conducted in CCPaMe to others Phytophthora species which are involved in Mediterranean ecosystems decline.