Data from: Climate-linked biogeography of mycorrhizal fungal spore traits

Climate-driven variation in traits is crucial for predicting ecological
responses to environmental change, yet global patterns and drivers of
microbial trait variation remain poorly understood. Using global datasets
of arbuscular mycorrhizal (AM) fungal observations linked to spore
morphological traits, we show that climate shapes spore trait variation
and functional diversity. Larger spore volumes were more prevalent in
warm, wet climates but were associated with smaller species range sizes,
suggesting a trade-off between persistence and dispersal potential.
Similarly, ornamented spores were more common in warm, wet climates and
were associated with narrower range sizes. Cell wall investment (i.e.,
wall thickness relative to volume) decreased in warmer, wetter climates
compared to cooler, drier ones, and was the strongest predictor of species
range size, with intermediate investment associated with larger geographic
distributions. Spore shape and color (i.e., melanin pigmentation) also
exhibited climate-driven patterns, with spherical spores and greater
pigmentation more common in warm, wet climates. Phylogenetic analyses
revealed high conservatism for spore ornamentation, moderate for volume,
low for color, and none for shape and cell wall investment. Additionally,
functional diversity analyses showed that warm, wet climates promote
higher within-community trait richness but lower trait divergence, while
broader climatic variability drives higher beta diversity. These findings
support growing evidence that trait-environment relationships extend to
microbial communities, reflecting ecological principles such as filtering,
evolutionary constraint, and dispersal-persistence trade-offs.
Incorporating microbial traits improves predictions of biogeographic
shifts and their cascading effects on plant-microbe interactions and
ecosystem stability under climate change.