INVESTIGADORES
SOLER ESTEBAN rosina Matilde
congresos y reuniones científicas
Título:
Flowering, seeding and natural regeneration in unmanaged and managed Nothofagus pumilio forests in South Patagonia
Autor/es:
MARTÍNEZ PASTUR, GUILLERMO; SOLER ESTEBAN, ROSINA MATILDE; LENCINAS, MARIA VANESSA; JUAN MANUEL CELLINI; PERI, PABLO LUIS
Lugar:
Campos de Jordão
Reunión:
Congreso; Latin American IALE Congress; 2009
Resumen:
Forest management in South Patagonian Nothofagus forests
are based on natural regeneration. Nothofagus pumilio forests have been
harvested through shelterwood cuts with variable retention, which can
impact biotic and abiotic processes and therefore influence the natural
regeneration cycle. To attain sustainable forest management, knowledge
of key aspects of these processes is required. The aim, here, was to
determinate patterns of flowering, seeding and seedling establishment in
primary and managed stands. Ten traps per stand (n=9) were collected monthly during two
seasons, analyzing flower and seed production in primary (PF) and
managed forests (aggregated retention-AR and dispersed retention-DR).
Bird, insect and mouse foraging, as well as seed quality and viability
were analyzed. Natural regeneration was measured in nine permanent
plots. The production patterns at the landscape level were compared
among the stands of the same treatment using multiple ANOVAs.
The number of abscissions of male and female flowers, immature
fruits, seeds, as well as reproductive and non-reproductive biomass
presented differences when stand type and month were analyzed. Values
were found to occur in descending order from PF to AR to DR. There were
no differences in all variables when annual production was compared,
except for reproductive biomass. The main losses during the whole cycle
were: in PF quality loss in seeds (39%), abscission (27%) and foraging
(18%); in AR quality loss in seeds (41%), abscission (26%) and
germination during establishment (19%); and in DR quality loss in seeds
(41%), foraging (20%) and germination during establishment (20%).
Seedling effective establishment during the first season attained up to
1.5% of the female flower production in PF, 0.8% in AR and 0.1% in DR.
Greater differences were found at the landscape level when stands of
same treatment were compared, varying their relevance according to the
year considered. Seed masting years were observed in different stands in
different years.
The number of propagules produced was exceedingly large
compared to the number of survivors. Our results showed a high
percentage of pollinated flowers were successful in producing fruits.
However, the main loss factors were associated with empty fruits,
foraging and establishment and survivor of the seedlings. Finally,
different flowering and seeding patterns were observed at the landscape
level, independently of their forest structure or the analyzed year.
Masting events were not coincident in all the stands and were not
associated to the management treatment.