Revista Chilena de Historia Natural 79 (3): 329-336, 2006
RESEARCH ARTICLE
Nurse effect in seedling establishment: facilitation and tolerance to damage in the Andes of
central Chile
Nurse effects, which occur when one plant species enhances the survival or growth of
another plant species, are predicted to be most relevant in stressful environments. These effects are particulary
important during seedling establishment due to their vulnerability to both biotic and abiotic factors, such as herbivory and drought.
Tolerance to herbivory reflects the degree to which plants are able to regrow and reproduce after damage, and should vary with
resource availability. In the high Andes of central Chile, the cushion plant Laretia acaulis (Apiaceae) acts as a buffer
against environmental stress, enhancing survival of several associated plant species. We hypothesized that tolerance to herbivory of
seedlings growing inside the canopy of L. acaulis should be greater than that of seedlings growing outside the cushion
plant. We conducted a field experiment to test this hypothesis for two native perennial species in the high Andes of central Chile:
Hordeum comosum (Poaceae) and Haplopappus anthylloides (Asteraceae). Seedlings of each species were
planted inside and outside L. acaulis cushions and half of them received manual damage (50 % foliar tissue removed).
Seedlings growing inside the nurse species showed high survival independent of the damage treatment. Whereas position (inside or
outside the cushion plant) did not affect tolerance of Haplopappus anthylloides, it significantly affected tolerance of
Hordeum comosum. Thus, we found similar survival of damaged and control seedlings of H. comosum inside
the cushions, but survival of damaged seedlings in the bare ground was lower than that of control seedlings. We verified the
occurrence of nurse effects of Laretia acaulis on the establishment of both species, and detected enhancement of
tolerance to damage in Hordeum comosum in this stressful habitat.
Key words:
facilitation,
Laretia acaulis, herbivory, tolerance, nurse effect
