Speakers

Biography

Camila is a biologist with a master’s degree at Universidad de Chile; she is currently doing her PhD thesis in the Ecology and Evolutionary Biology program at Universidad Austral de Chile. Her research is about plant and soil interactions, soil communities in forests, and how anthropogenic development has impacted this ecosystem. She has studied soil biodiversity associated with the forestry industry in southern Chile, and now she is studying how high-severity wildfires -which are a relatively new phenomenon in Chile- are affecting the soil ecosystem in endangered native forests.
 

Abstract

The rhizosphere is a key space in the soil where plants interact with soil communities and abiotic factors, sustaining a rich environment that promotes positive feedback between the plant and soil organisms. However, aggressive perturbations, such as high-severity wildfires, can eliminate not only plant communities but organic soil in a few hours, leading to retrogression of the soil ecosystem and, therefore, soil communities. In this work, we explore microbial and invertebrate communities associated with Gaultheria poeppigii (Ericaceae) rhizosphere in a temperate forest located in the Andes range after 7 years of high-severity wildfire. We sampled soil microbial and invertebrates from soil associated with the rhizosphere of G. poeppigii and bulk soil in areas affected by high and low-severity wildfires, as well as in sites not affected by fire (control) in China Muerta National Park (Chile). We extracted soil DNA and performed molecular analysis with Real-Time PCR for Bacteria (16S), Archaea (16S), and N-fixing bacteria (nifH). We also used Berlesse funnels to extract invertebrates. Our results indicate that after 7 years of ecosystem succession, soil communities have not fully reestablished, and bacteria and N-fixing bacteria are significantly less abundant in high and low-fire severity sites compared with control sites. We also found that rhizosphere soil had a higher abundance of N-fixing bacteria than bulk soil in control sites but not in sites affected by wildfire. Surprisingly, Archaea was more abundant in rhizosphere soil in low-severity sites compared to high-severity and control sites. On the other hand, invertebrates were also more abundant and communities were more diverse in control sites and in rhizosphere soil, but the later not always was statistically significant. These results highlight the role that plants play through their roots in the soil ecosystem, facilitating habitat to soil communities and promoting soil regeneration after severe perturbations such as wildfires. Furthermore, these results are important because wildfires as such are a relatively novel phenomenon in these ecosystems, which means that plants and soil organisms in this region have not evolved with this kind of perturbation, and therefore, it is crucial to assess the effects they have in the soil to propose ecological restoration measures.