Filtering of seed traits revealed by convergence and divergence patterns in subalpine grasslands

• Land use has an effect on seed strategies. It is debated, however, whether disturbances such as mowing select for one dominant regeneration strategy (e.g. ruderals) or allows for more species with diverse recruitment strategies to establish. We tested if there is a filtering of seed traits in subalpine grasslands and what is the effect of mowing on community mean seed traits and their diversity. We measured seed mass and seed number of most species from subalpine grasslands in the French Alps, in an experiment consisting of short- and long-term mowing. We calculated for each treatment average seed mass and number as well as functional divergence. Mowing had no effect either on mean seed trait values or trait diversity, but rather reversed the effect of moisture on seed traits. Most importantly, besides soil moisture, communities followed a continuum from grasslands dominated by species with heavy seeds to grasslands with high divergence in seed mass. These results suggest the existence of an axis of functional divergence convergence for seed mass in response to factors other than disturbance, though we were not able to identify which. Functional space (i.e. available niches along seed trait dimensions) exists for species with varied strategies in some of the communities, as opposed to others where species with heavy seed masses prevail. Reproductive strategies and the availability of diverse regeneration niches may determine a more important assembly rule of plant species in subalpine communities than previously considered.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

Nyckelord

Convergence

Divergence

Functional diversity

Seed mass

Seed number

Mowing

Regeneration niche

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