Data from: Genomic life-history traits mediate the impacts of habitat loss and nutrient availability on fragmented grassland communities

Habitat loss and nutrient enrichment are major drivers of plant species
declines. However, local extinction risks vary widely and are shaped by
life-history trait syndromes. Genomic life-history traits, which are
simple, stable, and widely available, offer a promising yet underexplored
approach to improving extinction risk assessments and informing
conservation efforts. Using a spatial comparison approach, we analysed 256
semi-natural grassland plant communities in four Swedish agricultural
landscapes to examine whether genomic life-history traits such as ploidy,
genome size, and chromosome number mediate differences in plant community
diversity and composition along independent gradients of grassland
fragment size and phosphorus availability. Our findings show that plant
diversity and community composition are increasingly dominated by larger
genome species both as grassland fragments become smaller and as more
phosphorus becomes available. While all genomic life-history traits proved
important, ploidy plays a particularly significant role in explaining
differences between observed plant communities. Ploidy-mediated
deterministic plant community changes along both environmental gradients.
Diploid species are especially vulnerable to local extinction, whereas
polyploids demonstrate resilience to habitat loss and benefit from
increased phosphorus availability, likely leading to the competitive
exclusion of diploids. By revealing how genomic traits shape plant
community responses to land-use change and nutrient pollution—two key
drivers of extinction—our study introduces a predictive, genomic
trait-based framework for assessing local extinction risks in fragmented
landscapes.