Latitudinal and Elevational Trends in Arbuscular Mycorrhizal Community Niche Structure

ABSTRACT Ecological niche volumes are hypothesised to decrease with latitude, with species distribution primarily shaped by abiotic factors at high latitudes and biotic factors at low latitudes. Similar patterns are expected along elevational gradients. We tested these predictions using global distribution and niche data for arbuscular mycorrhizal (AM) fungi. We found that temperature niche volumes increased with latitude, while precipitation niche volumes decreased, reflecting greater temperature and lower precipitation variability with increasing latitude. Niche differentiation in communities declined with latitude, suggesting a shift towards habitat filtering, driven primarily by similar temperature niches. Additionally, community niche structure along elevational gradients largely mirrored patterns observed in relation to latitude. These findings highlight the key role of abiotic filtering in structuring communities at high latitudes and suggest that similar ecological principles govern niche dynamics and community composition across latitudinal and elevational gradients.