Rehabilitation of eroded trails and gullies on quartzite rock outcrops with native species in a high-altitude grassland

• Published in: Journal of environmental management 2023-01, Vol.326, p.116569-116569, Article 116569
• Main Authors: Medeiros, Mirelli B., Cordeiro, Juni, Silva, Samuel Lourenço L., Salim, Ione H., Reis, André, Lacerda, Tomás Jansen, Lobo Seabra, Euler A., Oliveira, Mateus F., Moura, Sarah P., Santos, Izabel N.R., Bessa, Laura, Fonseca, Maria Thereza, Méndez-Quintero, Juan David, Nero, Marcelo Antônio, Maciel-Silva, Adaíses S., Scotti, Maria Rita
• Format: Article
• Language: English
• Subjects: Arbuscular mycorrhizal fungi; Bryophytes; Campo rupestre; Poaceae; Restoration; Soil water
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2022.116569

The quartzite rock outcrops and the native vegetation of grasslands located at the Serra da Calçada Mountain in Minas Gerais State (Brazil) have been severely degraded by extreme sports activities such as motocross and off-road vehicles, greatly damaging the abundant headwaters. The main consequences thereof were hilly and gully erosion processes with soil loss and the deviation of the water from its original paths. However, currently, there is no report of successful restoration efforts in severely eroded outcrops in Brazilian high-altitude grasslands (campo rupestre). Through the Universal Soil Loss Equation (USLE), we found a high general erosion rate in the study site (669.91 t·ha−1·year−1), and the specific soil loss provoked by off-road vehicles on trails was significantly greater (49 m3 per 100 m2) than that caused by mountain bikes and trekking (5.8 m3 per 100 m2). We performed the physical reconstruction of eroded outcrops and surface water flow paths by allocating locally available quartzite rocks. These rocks were inoculated with different species of bryophytes and planted with native species under two treatments: un-inoculated and inoculated with arbuscular mycorrhizal fungi (AMF) spores of the Rhizophagus irregularis species. After 2 years, the bryophyte communities showed a similar pattern to the preserved site, and the AMF inoculation favoured plant establishment of most species, especially of the Asteraceae, Cyperaceae, Fabaceae, Malpighiaceae, Orchidaceae and Poaceae families. The AMF also improved the soil fertility, highlighting soil P, SOM, CEC, NH4+-N as well as soil water content and water retention capacity. Poaceae family species showed an outstanding occupation, which was considered a functional indicator of rehabilitation success, functioning as a “hydraulic carpet” for water exportation, conduction and drainage across the outcrops. This study provides an eco-technology to restore severely eroded outcrops over headwaters using native species in the Brazilian high-altitude grasslands. [Display omitted] •Extreme sports have provoked erosion on outcrops and trails in campo rupeste.•Physical reconstruction of the outcrops was performed for water diversion.•Restoration was achieved using mosses and native species inoculated with mycorrhiza.•Inoculation increased soil fertility and plant growth.•Poaceae species dominated, functioning as a “hydraulic carpet”.