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2 resultados encontrados para: AUTOR: Thomas, Evert
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Fast-growing pioneer tree stands as a rapid and effective strategy for bracken elimination in the Neotropics
Douterlungne, David ; Thomas, Evert (coaut.) ; Levy Tacher, Samuel Israel (coaut.) ;
Contenido en: Journal of Applied Ecology Vol. 50, no. 5 (October 2013), p. 1257–1265 ISSN: 1365-2664
Resumen en: Inglés |
Resumen en inglés

1. Large areas of agricultural land around the world are degraded as a consequence of dominance by bracken fern (Pteridium spp.). Tropical production systems based on shifting cultivation and cattle breeding are particularly vulnerable to invasion of this species. In spite of this, effective methods for tropical bracken control are limited. 2. Fast-growing tree species have been used successfully to out-compete aggressively colonizing heliophytes and trigger natural succession. Drawing on a traditional Mayan management technique, we evaluate the potential of the pioneer tree balsa (Ochroma pyramidale) to control Pteridium caudatum in Chiapas, Mexico. We tested different bracken cutting frequencies and balsa propagation methods in a factorial randomized block experiment. Eighteen months later, we quantified bracken biomass under the young balsa canopy. 3. Living bracken rhizome biomass correlated significantly with balsa basal area, leaf litter biomass and understorey light intensity. While bracken rhizomes persisted in control plots, it was completely eradicated in plots with a minimum balsa basal area of 11 m2 ha 1. This threshold value was reached in less than 18 months with any of the tested propagation methods (seed broadcasting, direct sowing or nursery seedlings), on the condition of at least monthly bracken cutting during the first six months. 4. The ability of fast-growing broad-leaved pioneer trees like balsa to quickly out-compete bracken fern offers opportunities for large-scale application in tropical rural areas where economic and technical resources are scarce.

5. Synthesis and applications. Mayan subsistence farmers traditionally use balsa to outcompete invasive weeds, including bracken fern. Here, we highlight the usefulness of this method for quick and effective bracken control in southern Mexico. This approach, in combination with balsa’s short rotation cycle, creates opportunities to rapidly convert bracken land into forest stands with commercial potential, thus providing local income and increasing the likelihood of adoption by rural people. We encourage further research to test the potential of balsa and other fast-growing pioneer trees species for controlling bracken and similar weeds.

Human impact on wild firewood species in the Rural Andes community of Apillapampa, Bolivia
Thomas, Evert ; Douterlungne, David (coaut.) ; Vandebroek, Ina (coaut.) ; Heens, Frieke (coaut.) ; Goetghebeur, Paul (coaut.) ; Damme, Patrick Van (coaut.) ;
Contenido en: Environmental Monitoring and Assessment Vol. 178, no. 1-4 (2011), p. 333-347 ISSN: 0167-6369
Bibliotecas: San Cristóbal
SIBE San Cristóbal
39124-20 (Disponible)
Disponibles para prestamo: 1
Resumen en: Inglés |
Resumen en inglés

Firewood is the basic fuel source in rural Bolivia. A study was conducted in an Andean village of subsistence farmers to investigate human impact on wild firewood species. A total of 114 different fuel species was inventoried during fieldtrips and transect sampling. Specific data on abundance and growth height of wild firewood species were collected in thirty-six transects of 50 ×2 m(2). Information on fuel uses of plants was obtained from 13 local Quechua key participants. To appraise the impact of fuel harvest, the extraction impact value (EIV) index was developed. This index takes into account local participants' appreciation of (1) decreasing plant abundance; (2) regeneration capacity of plants; (3) impact of root harvesting; and (4) quality of firewood. Results suggest that several (sub-)woody plant species are negatively affected by firewood harvesting. We found that anthropogenic pressure, expressed as EIV, covaried with density of firewood species, which could entail higher human pressure on more abundant and/or more accessible species. The apparent negative impact of anthropogenic pressure on populations of wild fuel species is corroborated by our finding that, in addition to altitude, several anthropogenic variables (i.e. site accessibility, cultivation of exotics and burning practices) explain part of the variation in height of firewood species in the surroundings of Apillapampa.