Evolution of rarity and phylogeny determine above- and belowground biomass in plant-plant interactions

• Published in: PloS one Vol. 19; no. 5; p. e0294839
• Main Authors: Nytko, Alivia G, Hord, Ashlynn M, Senior, John K, O'Reilly-Wapstra, Julianne, Schweitzer, Jennifer A, Bailey, Joseph K
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 20.05.2024; Public Library of Science (PLoS)
• Subjects: Biological Evolution; Biological research; Biology and Life Sciences; Biology, Experimental; Biomass; Competition; Computer and Information Sciences; Ecological function; Ecology and Environmental Sciences; Ecosystem; Ecosystems; Eucalyptus; Eucalyptus - genetics; Eucalyptus - growth & development; Flowers & plants; Local population; Mixtures; Monoculture; Natural history; Phylogenetics; Phylogeny; Phylogeny (Botany); Plant biomass; Plant communities; Plant growth; Plants - classification; Population; Rare plants; Rare species; Species Specificity; Australia; United States; Tasmania Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0294839

Rare species are often considered inferior competitors due to occupancy of small ranges, specific habitats, and small local populations. However, the phylogenetic relatedness and rarity level (level 1-7 and common) of interacting species in plant-plant interactions are not often considered when predicting the response of rare plants in a biotic context. We used a common garden of 25 species of Tasmanian Eucalyptus, to differentiate non-additive patterns in the biomass of rare versus common species when grown in mixtures varying in phylogenetic relatedness and rarity. We demonstrate that rare species maintain progressively positive non-additive responses in biomass when interacting with phylogenetically intermediate, less rare and common species. This trend is not reflected in common species that out-performed in monocultures compared to mixtures. These results offer predictability as to how rare species' productivity will respond within various plant-plant interactions. However, species-specific interactions, such as those involving E. globulus, yielded a 97% increase in biomass compared to other species-specific interaction outcomes. These results are important because they suggest that plant rarity may also be shaped by biotic interactions, in addition to the known environmental and population factors normally used to describe rarity. Rare species may utilize potentially facilitative interactions with phylogenetically intermediate and common species to escape the effects of limiting similarity. Biotically mediated increases in rare plant biomass may have subsequent effects on the competitive ability and geographic occurrence of rare species, allowing rare species to persist at low abundance across plant communities. Through the consideration of species rarity and evolutionary history, we can more accurately predict plant-plant interaction dynamics to preserve unique ecosystem functions and fundamentally challenge what it means to be "rare".