Soil properties constrain forest understory plant distributions along an elevation gradient

Area of Science:

• Ecology
• Botany
• Environmental Science

Background:

• Climate warming projections often overlook non-climatic factors like soil properties.
• Existing data on soil factors are frequently at coarse spatial resolutions, not reflecting plant-level conditions.

Purpose of the Study:

• To investigate the impact of soil properties on plant occurrence and abundance along an elevation gradient.
• To determine if soil factors or dispersal limitation constrain plant range limits under climate change.

Main Methods:

• Conducted an intensive field survey of four spring forest herbs along an elevation gradient.
• Collected detailed soil data at fine spatial resolutions.
• Performed a seven-year transplant experiment with *Trillium erectum*.

Main Results:

• Soil properties significantly affected the occurrence and abundance of all studied species.
• Soil effects were more pronounced at higher elevations.
• High-elevation occurrences of *Trillium erectum* and *Claytonia caroliniana* were linked to rare microsites with high pH or nutrients.
• *Trillium erectum* individuals showed reduced growth at higher elevations, indicating environmental constraints.

Conclusions:

• Soil factors interact with climate to shape plant range limits along climatic gradients.
• Unsuitable soil conditions at high elevations or latitudes may impede future plant migration and biodiversity shifts.
• This research highlights the importance of fine-scale soil data in ecological modeling.