Post-agricultural tropical forest regeneration shifts soil microbial functional potential for carbon and nutrient cycling

Natural forest regeneration on abandoned agricultural land is an increasingly common, but understudied, landcover change in the tropics. We studied whether observed changes in microbial community composition with forest regeneration led to changes in functional potential. We used GeoChip 3.0 to measure microbial functional potential for carbon (C), nitrogen (N), phosphorous (P), and sulfur (S) cycling genes in pastures, early successional, and late successional forests in Puerto Rico. We found lower abundance and diversity of genes involved in C, N, and P in late successional forests compared to other landcover types. Soil microbial communities were functionally similar in active pastures and early successional forests. Our results suggest microbial functional potential varies with forest age, with potential implications for tropical biogeochemistry.