PRJNA526523
Parallel development of the Pentaclethra macroloba soil microbiome in contrasting past land-use histories of soil
Legacy attributes from previous land-use history have lingering effects on soils undergoing succession that has important consequences for overall ecosystem function in tropical secondary forests. Yet, even landscapes of similar origins with analogous past land-use histories have exhibited differing routes of forest recovery with different outcomes. There is increasing evidence that tree species-generated soil microbial heterogeneity is an important factor in facilitating regeneration, particularly nitrogen (N)-fixing tree species. However, it is unclear how past land-use history influences the coalescence of the soil microbiome of important N-fixing plants developing under these conditions; at different life stages of N-fixing plant development; and how this compares to a primary forest. To begin to address this, we examined differences in soil bacterial and fungal community composition and various soil abiotic factors (C, N, NO3-, NH4+, Cmic, pH, and % moisture), associated with large-, medium-, and small-sized Pentaclethra macroloba trees in a primary forest, and in a 23-year-old secondary forest, in the Maquenque National Wildlife Refuge (MNWR) in Costa Rica. We show that as the Pentaclethra trees develop, the soil bacterial- and fungal-microbiome associated with Pentaclethra also changes, and that these soil microbiomes can become similar even when developed in soils with contrasting past land-use histories. We found that soil NH4+ and NO3- explained 61% of the variation in the soil bacterial community composition of small trees between the primary and secondary forest. This highlights the importance of inorganic N during tree soil microbiome development in contrasting past land-use history of soils. Moreover, soil nutrients were important in structuring these soil microbiome communities across Pentaclethra tree size in the secondary forest; whereas soil pH and % moisture were the soil environmental drivers of the soil bacterial and fungal community composition across Pentaclethra-large, medium, and small tree sizes in the primary forest. These results show that Pentaclethra and its associated soil microbiome develop and undergo succession together, and that this may have important implications for forest restoration trajectories in the MNWR.