Repeated Selective Cutting Controls Neotropical Bracken (Pteridium arachnoideum) and Restores Abandoned Pastures

• Published in: Invasive plant science and management 2014-12, Vol.7 (4), p.580-589
• Main Authors: Aguilar-Dorantes, Karla, Mehltreter, Klaus, Vibrans, Heike, Mata-Rosas, Martin, Esqueda-Esquivel, Valentín A
• Format: Article
• Language: English
• Subjects: biomass; community structure; control methods; cutting; Dennstaedtiaceae; ferns; forests; humid zones; invasive plants; invasive species; leaves; mechanical weed control; monitoring; pastures; plant growth; plant litter; Pteridium; Pteridium aquilinum; regrowth; restoration; rhizome; rhizomes; shade; shading; shoots; soil depth; tropics
• ISSN: 1939-7291; 1939-747X; 1939-747X
• DOI: 10.1614/IPSM-D-13-00062.1

Neotropical bracken fern invades disturbed forests and burned and abandoned pastures in Latin America, inhibiting the growth of associated vegetation and altering community structure. Cutting of all aboveground vegetation every 6 to 12 mo has proven to be inefficient as a control method. We studied the impact of selective cutting of bracken every 2 mo, shading, and a combination of cutting + shading during 14 mo in a bracken-dominated, abandoned pasture in Veracruz, Mexico. At the end of the experiment, cutting with or without shading drastically reduced bracken cover from >90% to less than 1%, decreased leaf number from 18 to fewer than two leaves per m2, and depleted bracken leaf biomass. The significant reduction of bracken was correlated with a significant 3.9- to 5.7-fold increase in richness of other plant species. Cutting without shading was the only treatment that significantly reduced rhizome biomass to less than 62% of control plots, whereas cutting + shading was the only treatment to promote a significant increase in both cover and shoot biomass of successional plant species. Selective cutting of P. arachnoideum repeated every 2 mo was more successful than nonselective cuttings repeated at longer intervals, because it removed newly emerging leaves before their complete expansion and supported the recovery and reestablishment of other plant species, which may help to control bracken. Although costs for the first year of selective cutting were twice as much as for nonselective cutting, it may prove less expensive and more efficient than nonselective cutting in the long term. Nomenclature: Bracken, Pteridium spp., Neotropical bracken fern, Pteridium arachnoideum (Kaulf.) Maxon. Management Implications: The selective cutting of bracken leaves and the removal of all leaf litter is a viable strategy to restore abandoned, bracken-infested pastures. Selective cutting of bracken promotes the establishment and recovery of pasture species, which help to control bracken. Repeated cutting should be performed according to the rate of bracken regrowth at each site and should always be applied before newly emerging leaves have completely expanded and begun to return photosynthetic products back into the rhizome. After six subsequent cuttings, bracken cover should be less than 1%. In tropical humid climates, cutting should be performed up to six times per year because of continuous plant growth throughout the year. Monitoring the reduction of the rhizome biomass