Changes in Soil-Borne Communities of Arbuscular Mycorrhizal Fungi during Natural Regrowth of Abandoned Cattle Pastures Are Indicative of Ecosystem Restoration

Abstract

Natural restoration of ecosystems includes the restoration of plant-microbial associations; however, few studies had documented those changes in tropical ecosystems. With the aim to contribute to understand soil microbial changes in a natural regrowth succession of degraded pastures that were left for natural restoration, we studied changes in arbuscular mycorrhizal (AM) fungal communities. Arbuscular mycorrhizal fungi (AMF) establish a mutualistic symbiosis with plants, improving plant nutrition. Amplification of the small subunit rRNA with specific primers and subsequent Illumina sequencing were used to search soil-borne AM fungal communities in four successional natural regrowth stages in two landscapes (hill and mountain) with soil differences, located in the Andean-Amazonian transition. Molecular results corroborated the results obtained previously by spores-dependent approaches. More abundance and virtual taxa of AMF exist in the soil of degraded pastures and early natural regrowth stages than in old-growth or mature forest soils. Although changes in AM fungal communities occurred similarly over the natural regrowth chronosequence, differences in soil texture between landscapes was an important soil feature differentiating AM fungal community composition and richness. Changes in soil-borne AM fungal communities reflect some signals of environmental restoration that had not been described before, such as the reduction of Glomus dominance and the increase of Paraglomus representativeness in the AM fungal community during the natural regrowth chronosequence.

Plant Biodiversity Homogenization across the Chronosequence in Highly Fragmented Landscapes in the Colombian Andean–Amazonian Transition

“…The pH and soil penetrations were typically altered by the cattle pasture use history of those forests [64]. Rodríguez-León et al [22] reported that soil pH decreases and organic carbon and nutrients such as Ca and Mg increase along the successional trajectory, favoring the establishment of arbuscular mycorrhizal fungal communities that are strongly associated with less-disturbed ecosystems. Likewise, the physical and biological quality of the soil is favored by natural regeneration, which will have a direct impact on the increase of species richness and composition of the plant community [23].…”

“…Another determining factor in the regeneration pattern of vegetation cover is soil. The evidence suggests broad variation in the physical, chemical and biological conditions of the soil during secondary succession [22,23]. The wide heterogeneity of soils and their response to changes in cover generates a multifactorial scenario that may govern recovery trends for vegetation cover during natural regeneration.…”