Positive feedbacks between plant invasions and fire regimes: <Emphasis Type="Italic">Teline monspessulana</Emphasis> (L.) K. Koch (Fabaceae) in central Chile |
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Authors: | Aníbal Pauchard Rafael A García Eduardo Peña Cristian González Lohengrin A Cavieres Ramiro O Bustamante |
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Institution: | (1) Facultad de Ciencias Forestales, Universidad de Concepción, Casilla 160-C, Concepcion, Chile;(2) Instituto de Ecología y Biodiversidad (IEB), Santiago, Chile;(3) Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepcion, Chile;(4) Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile |
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Abstract: | Invasive species can increase fire frequency and intensity, generating favorable conditions for their self-perpetuation. Mediterranean
south-central Chile may be especially prone to the effects of invasive species on fire regimes because it is less adapted
to fire and it contains a highly endemic flora. Teline monspessulana (L.) K. Koch (syn. Cytisus monspessulanus L.; Genista monspessulana (L.) L.A.S. Johnson) is an introduced shrub that forms monotypic stands or is present as an understory species in native
forests as well as in forestry plantations. Dense T. monspessulana stands are completely destroyed by fire, generating the conditions for it seeds to germinate and establish an abundant regeneration,
with up to 900 plants/m2. We report key evidence on abundance and biomass in adult stands, and patterns of seed bank and regeneration after fire in
stands of T. monspessulana around the city of Concepción, Chile. We estimated living biomass in pure stands and underneath Eucalyptus plantations. In burned areas, we assessed T. monspessulana seed bank and studied regeneration patterns. We found that T. monspessulana densities reaches 52,778 plants/ha and 8.92 ton/ha in pure stands and 34,223 plants/ha and 2.31 ton/ha underneath Eucalyptus plantations. T. monspessulana generates small caliper fuel and acts as a ladder-fuel. Large soil seed banks allow for abundant regeneration after fire,
with mean densities of 877,111 plants/ha, but an overall mortality of 37.2% in the first year after the fire. The high values
of regeneration compared to final densities in adult stands suggest that density-dependent mortality. Our results indicate
that T. monspessulana regeneration is not only favored by fires, but also that the species creates favorable conditions for intense and continuous
fires, both under pure conditions, but also associated to exotic tree plantations. To understand the implications of positive
feedbacks between invaders and fire, we recommend focusing in the mechanisms by which they increases fuel accumulation and
fuel flammability, and how higher fire frequency and intensity favors invasive species recruitment over native species. Comprehension
of this dynamics will allow for better management and control of these invasions which have major ecological, economical and
social implications. |
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Keywords: | Invasive species Wildfires fuel Impacts Seedbank Post-fire shrub regeneration |
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