Format: ORAL

Marta Nieto-Lugilde1, Diego Nieto-Lugilde2, Bryan T. Piatkowski3, Aaron M. Duffy1, Blanka Aguero1, A. Jonathan Shaw1

1 Department of Biology, Duke University, Durham, USA 2 Departamento de Botánica, Ecología y Fisiología Vegetal, Universidad de Córdoba, Córdoba, Spain 3 Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, USA

Evolutionary drivers play a pivotal role in shaping biodiversity and influencing how species adapt and change over time. The process of habitat adaptation and evolution helps species better fit their environments, increasing their chances of survival and successful reproduction. Sphagnum species are remarkable in their ability to construct and modify their own niches, which are often well differentiated among species. Nevertheless, the scarcity of morphological characters that separate the species poses a challenge in identifying ecological traits crucial for understanding their evolution and systematics. A current contentious topic revolves around the classification of the widely distributed S. magellanicum into several morphologically indistinguishable taxa. The recent addition of two newly described species brings the count of North American species to four: S. diabolicum, S. divinum, S. magniae, and S. medium. Sphagnum, especially the S. magellanicum complex, has been developing as a model group for ecological genomics. To explore differences among these cryptic species in microhabitats and climate niches, we developed barcode markers and used RADseq analyses on 808 collections from 119 sites across eastern North America. Microhabitats, classified by hydrology and shade, alongside hierarchical modeling of species communities, were assessed for niche variation among species. Surprisingly, S. diabolicum showed not significant responses to any variable, whereas the other complex members exhibited diverse responses. Climatic variables strongly influenced S. magniae but less so for S. diabolicum, S. divinum, and S. medium. Micro-habitat variables minimally affected occurrence variation for all species, whereas random variables (sample and locality) explained significant variation for S. diabolicum, S. divinum, and S. medium. These results suggest that there are still unmeasured but important ecological traits impacting species occurrence.Our findings underscore the intricate interplay between species and their environments, emphasizing the varying impacts of climate and local factors on Sphagnum species.