The role of native woody species in the restoration of Campos Rupestres in quarries
Résumé
Questions: Can shrub and tree seedlings be reintroduced into an extremely harsh environment through transplantation? Does the growth strategy of species affect their survival? What factors influence transplantation success? Do transplanted species influence their immediate vicinity, e.g. promote native species colonization?
Location: Campos Rupestres, Minas Gerais, Brazil.
Methods:We studied the reintroduction of four native tree and 14 native shrub species. Their transplantation success (survival, growth and reproduction) and their impact on their immediate vicinity (understorey composition, soil surface indicators, e.g. cover of moss, biological crust, bare ground, litter, herbaceous cover and soil characteristics) were assessed 4.5 yrs after transplantation.
Results: While some transplanted species had low survival (<30%), half of them had survival of >78% 4.5 yrs after transplantation. Plant growth was barely correlated with transplantation success in such a harsh environment. Transplanted species did not influence soil and understorey plant composition but significantly impacted soil surface indicators. The shrub species with higher survival usually allowed establishment of an understorey herbaceous cover, which may increase soil erosion control. This is also true for some species for which the survival was <40%: Diplusodon orbicularis (survival: 39%) and Lavoisiera campos-portoana (37%). Crown volume had a direct effect on light reaching the soil (e.g. Jacaranda caroba or Collaea cipoensis had a less dense canopy more permeable to light, allowing the development of understorey species). On the other hand, crown volume was positively correlated with amount of litter: Fabaceae, e.g. Chamaecrista semaphora and Mimosa foliolosa, had denser canopy and produced a thick layer of litter, limiting herbaceous species establishment. Three tree species (Enterolobium ellipticum, Kielmeyera petiolaris and Zeyhera tuberculosa) neither had high survival nor facilitated establishment of herbaceous cover. The layout and spacing of species and individuals must thus be considered carefully to ensure recolonization by native shrub and herbaceous species.
Conclusion: This study demonstrates the practical efficiency of using some species native to harsh tropical ecosystems, e.g. Campos Rupestres, to restore quarry ecosystems in terms of their transplantation success, effects on both the establishment of herbaceous species and soil conservation
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