INVESTIGADORES
MARTINEZ PASTUR Guillermo Jose
artículos
Título:
Understorey succession in Nothofagus forests in Tierra del Fuego (Argentina) affected by Castor canadensis.
Autor/es:
MARTÍNEZ PASTUR G; LENCINAS MV; J ESCOBAR; QUIROGA P; MALMIERCA L; LIZARRALDE M
Revista:
APPLIED VEGETATION SCIENCE
Editorial:
Oppulus Press
Referencias:
Año: 2006 vol. 9 p. 143 - 154
ISSN:
1402-2001
Resumen:
Question: Does understorey richness, cover and biomass
change during succession in abandoned Castor canadensisDoes understorey richness, cover and biomass
change during succession in abandoned Castor canadensisCastor canadensis
impoundments of riparian Nothofagus forests?Nothofagus forests?
Location: Magellanic Nothofagus forests at Tierra del Fuego
National Park (54°50'32.4'' S, 68°32'11.5'' W), Argentina.Magellanic Nothofagus forests at Tierra del Fuego
National Park (54°50'32.4'' S, 68°32'11.5'' W), Argentina.°50'32.4'' S, 68°32'11.5'' W), Argentina.
Methods: Five meadows of different time since abandonment
(1, 5, 6, 9 and 20 years ago) and two controls (pure N. pumilioFive meadows of different time since abandonment
(1, 5, 6, 9 and 20 years ago) and two controls (pure N. pumilioN. pumilio
and mixed N. pumilio - N. betuloides forests) were sampled.
Understorey variables (species richness, cover and biomass)
in beaver meadows were measured at eight plots, as well as
sapling and seedlings age and height. In control treatments, ten
plots on each forest type characterized forest structure.N. pumilio - N. betuloides forests) were sampled.
Understorey variables (species richness, cover and biomass)
in beaver meadows were measured at eight plots, as well as
sapling and seedlings age and height. In control treatments, ten
plots on each forest type characterized forest structure.
Results: Beavers alter vegetation dynamics, modifying biomass
and composition of the original forest communities.
Richness, cover and biomass were significantly modified when
compared to the original understorey. Ferns are the most
affected group, while grasses became more abundant. Many
species established in the impacted sectors, which did not
grow in primary forests. Trees did not regenerate in impacted
areas for long periods, and many understorey original species
are missing. Nothofagus forests are not adapted to support a
long-term beaver impact.Beavers alter vegetation dynamics, modifying biomass
and composition of the original forest communities.
Richness, cover and biomass were significantly modified when
compared to the original understorey. Ferns are the most
affected group, while grasses became more abundant. Many
species established in the impacted sectors, which did not
grow in primary forests. Trees did not regenerate in impacted
areas for long periods, and many understorey original species
are missing. Nothofagus forests are not adapted to support a
long-term beaver impact.Nothofagus forests are not adapted to support a
long-term beaver impact.
Conclusions: Beavers modify the original ecosystem from
closed forest to a grass- and sedge-dominated meadow, due to
the lack of adaptive regeneration strategies in the NothofagusBeavers modify the original ecosystem from
closed forest to a grass- and sedge-dominated meadow, due to
the lack of adaptive regeneration strategies in the NothofagusNothofagus
forests. The maintenance of the present level of the beaver
population is not sustainable over time, due to utilized and
impacted tree biomass which could not be replaced by the
natural dynamics of the forest ecosystem.