Using a bioindicator species to evaluate soil limitations for the recruitment of a recalcitrant tree seed species of Central Chile threatened by climate change

Narkis S Morales ^1* Ignacio C Fernández ^2* Joaquín Riquelme-Alarcón ³ Eduardo C. Arellano ^1,4,5

• ¹ Departamento de Ecosistemas y Medio Ambiente, Facultad de Agronomía y Sistemas Naturales, Pontificia Universidad Católica de Chile, Santiago, Santiago Metropolitan Region (RM), Chile
• ² Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Santiago, Santiago Metropolitan Region (RM), Chile
• ³ Centro de Modelación y Monitoreo de Ecosistemas, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
• ⁴ Center for Applied Ecology and Sustainability, Faculty of Biological Sciences, Pontifical Catholic University of Chile, Santiago, Santiago Metropolitan Region (RM), Chile
• ⁵ Instituto para el Desarrollo Sustentable, Pontificia Universidad Católica de Chile, Santiago, Chile

Climate change presents significant challenges to plant species, especially those with recalcitrant seeds. Beilschmiedia miersii, an endangered tree species endemic to the Mediterranean zone of Chile, exemplifies this vulnerability, exhibiting restricted seeding and recruitment in some areas. Due to the challenges associated with conducting experiments with recalcitrant seeds, a surrogate bioindicator species was employed in this study (Lens culinaris). Seeds were planted in petri dishes using soil samples collected from 15 sites where B. miersii was dominant. Germination, mortality, and growth were measured to assess differences between soil origins, and the influence of various abiotic factors were evaluated. The study's findings indicate that soil conditions at the examined sites do not pose significant limitations to germination and plant growth. This suggests that the studied sites retain the potential for recruitment, despite the observed variations in soil and site conditions. The results imply that other factors may be impeding recruitment success. While further research is needed to identify the specific factors hindering recruitment and develop effective conservation strategies, this study provides valuable insights into the potential limitations affecting B. miersii recruitment. These findings highlight the importance of considering multiple environmental factors beyond soil conditions when addressing recruitment challenges in threatened species.