Do large-seeded herbs have a small range size? The seed mass-distribution range trade-off hypothesis

Area of Science:

• Ecology
• Biogeography
• Conservation Biology

Background:

• The seed mass-distribution range trade-off hypothesis suggests smaller seeds, with better dispersal, correlate with larger ranges.
• Environmental factors significantly influence species' seed mass and distribution, impacting habitat vulnerability.

Purpose of the Study:

• To test the seed mass-distribution range trade-off hypothesis.
• To investigate how environmental factors (soil moisture, light, nutrients) affect seed mass and range size.
• To identify species and habitats at risk of local extinction.

Main Methods:

• Compiled data on seed mass, global range size, and habitat environmental factors for 1,600 species in the Pannonian Ecoregion.
• Utilized literature data for species traits and environmental indicators.
• Statistically analyzed the relationships between seed mass, range size, and environmental variables.

Main Results:

• Confirmed a negative correlation between seed mass and range size, supporting the trade-off hypothesis.
• Seed mass increased with lower light intensity and higher nutrient availability, but decreased with higher soil moisture.
• Range size increased with soil moisture and nutrient supply, but decreased with higher light intensity.

Conclusions:

• The seed mass-distribution range trade-off is validated across a large species pool.
• Species in dry, low-nutrient, high-light habitats (e.g., dry grasslands) exhibit smaller ranges and are potentially more vulnerable.
• Understanding these biogeographic patterns is essential for setting conservation priorities and protecting at-risk species.