Conspecific leaf litter and root competition inhibits shrub emergence in the Patagonian steppe

M. VICTORIA CAMPANELLA; ALEJANDRO J. BISIGATO

PLANT ECOLOGY

SPRINGER

Lugar: Berlin; Año: 2019

1385-0237

A critical stage in the establishment of new individuals is seedling emergence and litteris a main factor affecting this stage. Recent research found that adults of Chuquiraga avellanedae are over-dispersed. Among several mechanisms, this pattern might be due to the negative influences of adults on seedlings through root competition. We performed field and glasshouse experiments to evaluate i) the effects of C. avellanedae leaf litter and rootpresence on the emergence of conspecific seedlings, and ii) the effects of leaflitter type (C. avellanedae litter, inertlitter, no litter) and seed burial depth (seed at the surface or buried) on the emergence of C. avellanedae and Nassella tenuis (dominant grass) seedlings.The field experiment demonstrated root competition from adult plants on shrub seedlings, reducing seedling emergence. However, the effect of root competition did not differ between microsites (under shrubs vs. between-shrubs). We dismiss the effect of allelopathy because inert litter (i.e. plastic leaves) had thesame negative effect as C. avellanedae litter, indicating a mechanical effect. The glasshouse experiment revealed aspecies-specific response of seedling emergence. C. avellanedae litter limits the emergence of conspecific seedlings but was neutral with regard to the emergence of grass seedlings (N.tenuis). No differences in root competition between microsites and reduction of shrub seedlings by litter suggest that the over-dispersed pattern found for C. avellanedae is caused, at least partially, by litter effects on seedling emergence.