Management techniques for the control of Melinis minutiflora P. Beauv. (molasses grass): ten years of research on an invasive grass species in the Brazilian Cerrado

Abstract

Th e invasion of exotic species is considered to be a major threat to the preservation of biodiversity. In the Parque Nacional de Brasília (National Park of Brasília), the invasive Melinis minutifl ora (molasses grass) occupies more than 10 % of the area of the park. Th e present, long-term, study compared two treatments of exposure to molasses grass: 1) fi re and 2) integrated management (fi re + herbicide sprays + manual removal). Th e aerial biomass of molasses grass in the experimental area initially represented ca. 55 % of the total aerial biomass, a percentage that apparently did not infl uence native plant species richness at this site. Fire alone was not suffi cient to control molasses grass, which attained its pre-treatment biomass values after two years. Integrated management reduced, and maintained, biomass to less than 1 % of its original value after ten years, and maintained this level throughout the study, demonstrating that it is a promising strategy for the recovery of areas invaded by molasses grass in the Cerrado. However, because of the recolonization by molasses grass, long-term monitoring eff orts are targeting outbreaks, which would require immediate intervention in order to maintain the native biological diversity of the region.

Effectiveness and costs of invasive species control using different techniques to restore cerrado grasslands

“…The inefficacy of fire in controlling invasive grasses has been demonstrated by previous studies of invasive species control in Brazil and Australia (e.g. Rossiter et al 2003 for Andropogon gayanus , Martins et al 2011, 2017 for Melinis minutiflora , Gorgone‐Barbosa et al 2015 for Urochloa brizantha ).…”

“…Although fire alone was not effective, as a complementary technique it reduced costs of hoeing, likely by depleting the seed bank of U. decumbens and making future hoeing operations easier. In a previous experiment aiming to control the invasion by another African grass ( Melinis minutiflora ) in cerrado vegetation (Martins et al 2011, 2017), burning in different seasons was compared to a combination of fire + glyphosate + manual removal of seedlings. Besides the minor effect of fire independent of the burn season, the authors found that combining fire, glyphosate, and hand weeding reduced drastically the biomass of the invader (Martins et al 2017).…”

Savannas after afforestation: Assessment of herbaceous community responses to wildfire versus native tree planting

“…In Brazilian Cerrado, savannas have higher rates of flowering (Pilon, Hoffmann, et al, 2018) and increase in native herbaceous biomass after fire (Oliveras et al, 2013). Although the mechanisms by which fire directly stimulates resprouting, flowering, and seed germination are still not clear (Buisson et al, 2019;Fidelis, Rosalem, Zanzarini, & Camargos, 2019), fire does indirectly stimulate herbaceous plants by increasing light availability and soil nutrients (Araújo, Amaral, Bruna, & Vasconcelos, 2013) and increases native species richness by reducing exotic grass cover (Martins, Hay, Scaléa, & Malaquias, 2017).…”

“…In Brazilian Cerrado, savannas have higher rates of flowering (Pilon, Hoffmann, et al, 2018) and increase in native herbaceous biomass after fire (Oliveras et al., 2013). Although the mechanisms by which fire directly stimulates resprouting, flowering, and seed germination are still not clear (Buisson et al., 2019; Fidelis, Rosalem, Zanzarini, & Camargos, 2019), fire does indirectly stimulate herbaceous plants by increasing light availability and soil nutrients (Araújo, Amaral, Bruna, & Vasconcelos, 2013) and increases native species richness by reducing exotic grass cover (Martins, Hay, Scaléa, & Malaquias, 2017). In sum, our results should be viewed as supportive of the growing recognition that fire is of fundamental importance to the conservation and restoration of savannas in Brazilian Cerrado (Durigan & Ratter, 2016; Fidelis et al., 2019; Maravalhas & Vasconcelos, 2014; Ramos‐Neto & Pivello, 2000; Schmidt et al., 2018; Zanzarini et al., 2019).…”

Impact of Climate Change on the Potential Distribution of Native and Invasive Grasses in the Cerrado

“…It is worth mentioning that the control and/or eradication of invasive species is very difficult. In the National Park of Brasilia, management initiatives for the species M. minutiflora have been carried out since 2003 (MARTINS et al, 2017). According to the authors, after ten years of study, the only way to reduce the infestation of the species was an integrated management that consisted of controlled burning (2003), punctual application of herbicide (2004) and manual removal of seedlings (every year between 2005 and 2013).…”