INVESTIGADORES
GARIBALDI Lucas Alejandro
congresos y reuniones científicas
Título:
Environmental vs. genetically-based foliar traits and resistance to herbivores in Patagonian southern beeches
Autor/es:
GARIBALDI, L. A.; CHANETON, E. J.; KITZBERGER, T.; MAZÍA, C. N.
Reunión:
Congreso; 95th ESA Annual Meeting; 2010
Resumen:
Background/Question/Methods
Spatial
environmental heterogeneity can drive different plant syndromes within
the habitat of one species. Tree species forming natural monospecific
stands along wide habitat distribution, such us the southern beech Nothofagus pumilio,
can be useful to understand the influence of abiotic and biotic factors
on constitutive plant traits and genotypic × environmental interactions
without the confounding effects of plant species composition changes
among sites.
Our objectives were to: 1)
identify plant constitutive syndromes in terms of growth rates, leaf
phenology, and leaf traits; 2) evaluate the association between these
syndromes and the characteristics of their site of origin
(precipitation, temperature, and folivory); 3) understand the
consequences of these syndromes on plant survival and resistance to
herbivory in contrasting environments. We collected juvenile plants
(c.a. 30cm high) originated from six different environments in terms of
precipitation, temperature, and herbivory within N. pumilio
monospecific forests of northern Patagonia (Argentina). Each population
was planted at two contrasting sites, one dry and warm forest (40º36S,
71º05W, annual precipitation: 1150mm year-1) with high abundance of insect folivores and mammals herbivores, and one wet and cold forest (40º37S, 71º50W, 2750mm year-1)
with low abundance of both types of herbivores. In each plant, we
measured survival, growth, leaf phenology, leaf size, leaf toughness,
leaf density of trichomes, folivory by different insect guilds, and
browsing by mammals.
Results/Conclusions
We
found differences in plant syndromes associated to the annual
precipitation and mean temperature of the site of origin. At both
contrasting planting sites, the three populations originated from drier
and warmer forests showed lower trichome density, smaller leaf size, and
earlier bud breaking and leaf expansion than the three origins from
wetter and colder forests. All origins showed earlier leaf phenology and
higher leaf toughness when planted in the dry/warm forest compared to
the wet/cold forest, but we found no difference between forest sites in
trichome density. In general, folivory received by each plant population
was negatively associated with the mean annual precipitation of the
site of origin, and positively associated with mean temperature. Plant
populations did not differ in survival so far, but all origins showed
lower survival in the dry/warm forest site. Our results suggest that
trichome density is under genetic control, showing no plastic responses
to contrasting environmental conditions. We conclude that N. pumilio
populations show constitutive traits associated with climatic
conditions of the site of origin that provide differential resistance to
herbivory.