Banco de semillas de relaves mineros como indicador de recuperación de vegetación en Brasil

Abstract

Introducción: El banco de semillas en el suelo es uno de los indicadores ecológicos más importantes para la evaluación y monitoreo de recuperación de ecosistemas degradados. Así mismo, actualmente indicadores ecológicos de restauración son usados en áreas afectadas por la ruptura de la represa de relaves de Fundão en Mariana, Minas Gerais, Brasil. Objetivo: En este estudio se evaluó la variación de la riqueza, composición de especies, densidad y parámetros fitosociológicos del banco de semillas en dos profundidades de relaves mineros en Mariana, municipio de Mariana, Minas Gerais, Brasil. Métodos: Se recolectaron 15 muestras por nivel de profundidad, en la capa superior (Profundidad1, P1 = 0-2.5 cm) y capa inferior (Profundidad2, P2 = 2.5-5.0 cm) del relave de minería para examinar el banco de semillas viable, que luego se colocó en un invernadero para la germinación. Posteriormente se contaron e identificaron semanalmente todos los individuos de cada especie durante un período de seis meses. Resultados: Se demostró que existe un banco de semillas en las capas superficiales de relaves mineros acumulados en las áreas afectadas de Mariana, con una marcada diferencia entre profundidades en términos de riqueza de especies y densidad de individuos. Se observó una mayor riqueza y número de individuos en P1, (1 165 semillas germinadas), pertenecientes a 18 familias y 47 especies, en comparación a P2 (197 individuos), pertenecientes a 12 familias y 23 especies. El banco de semillas de la capa P1 está influenciado por la lluvia de semillas del bosque cercano. Por otro lado, el banco de semillas de P2, puede ser característico de los relaves mineros. Conclusiones: El banco de semillas estudiado puede tener efectos positivos sobre la recuperación en el área de estudio, debido a la alta proporción de especies nativas, pioneras y anemocóricas típicas de etapas iniciales de sucesión secundaria.

Relationship between soil seed bank and forest restoration techniques on areas around bauxite mining environment

“…The soil seed bank of both areas under restoration showed higher density of herbaceous individuals and richness of herbaceous species. This result corroborates studies carried out in areas undergoing secondary succession in the tropical forest (Miranda-Neto 2014b;Silva et al, 2019;Balestrin et al, 2019;Silva et al, 2021a;Martins et al, 2021;Silva et al, 2021b;Adjalla et al, 2022). These results suppose that the dominance of the herbaceous life form is related to the short life cycle of these species, high seed production and environmental conditions after disturbance, such as higher luminosity due to the lower plant coverage.…”

“…This pattern is common in early successional stage forests (Miranda-Neto et al, 2016;Balestrin et al, 2019;Martins et al, 2021). For example, the soil seed bank in tropical regions is mainly composed of pioneer species, light-demanding and has a higher density of seeds in the surface layers of the soil (Martins et al, 2015;Silva et al, 2021a;Martins et al, 2021). Several studies report the importance of seeds of pioneer species stored in the soil and their role in the formation of a persistent bank, due to high seed production, efficient dispersal mechanisms, long seed viability and rapid growth (Kunz & Martins 2016;Balestrin et al, 2019;Silva et al, 2019;Miranda-Neto et al, 2021;Silva et al, 2021a;Adjalla et al, 2022).…”

“…For example, the soil seed bank in tropical regions is mainly composed of pioneer species, light-demanding and has a higher density of seeds in the surface layers of the soil (Martins et al, 2015;Silva et al, 2021a;Martins et al, 2021). Several studies report the importance of seeds of pioneer species stored in the soil and their role in the formation of a persistent bank, due to high seed production, efficient dispersal mechanisms, long seed viability and rapid growth (Kunz & Martins 2016;Balestrin et al, 2019;Silva et al, 2019;Miranda-Neto et al, 2021;Silva et al, 2021a;Adjalla et al, 2022). However, for the results show that the floristic composition, the Shannon diversity indices (Area A: H' = 2.970 and Area B: H' = 2.768) indicating higher diversity and the Pielou equabilities (Area A: J' = 0.790 and Area B: J' = 0.741) indicate floristic heterogeneity in both areas.…”

“…The floristic results of this research reflect the contributions of the implemented restoration techniques, such as: Seeds from soil transposition, direct sowing and green manuring; Propagules dispersed by planted trees and the attraction of seed-dispersing fauna by zoochoric species (Viani et al, 2015;Silva et al, 2015;Corlett 2017;Aslan et al, 2019;. Seeds can be deposited at different depths in the soil, depending on the quantity, weight and size of the seeds, however, several studies indicate a higher density of seeds in the surface layers of the soil Miranda-Neto et al 2016;Menezes et al 2019;Balestrin et al, 2019;Silva et al, 2021a;Martins et al, 2021). In this sense, understanding the relationship between the soil seed bank and seed dispersal is critical to understanding the establishment of plant populations and community dynamics (Aslan et al, 2019).…”

Complementing seedling planting with nucleation techniques increases forest restoration potential in areas around bauxite mining

“…Furthermore, the presence of native species strengthens the resilience potential of the soil seed bank, especially in the face of disturbances (Martins et al, 2021; Silva, Martins, & Balestrin, 2021). Species with tree life forms contribute to faster vegetation structure recovery (Adjalla et al, 2022; Silva, Martins, Villa, et al, 2021). Pioneer species grow faster and can facilitate species recruitment from late successional stages (Balestrin et al, 2019; Miranda‐Neto et al, 2016).…”