Orthophosphate fluxes in scattered trees from fragmented Andean landscapes highlight a biogeochemical role of foliar traits in pioneer species

Highly diverse neotropical ecosystems exhibit a natural limitation of phosphorus in the soil, sufficient to limit productivity and structure. This is more pronounced in Andean ecosystems, with high forest fragmentation and forest loss rates aggravating the effect. Previous studies have highlighted the importance of precipitation and its interaction with the canopy on nutrient inputs into forests. However, few studies have quantified the potential effects of structural and morphological tree diversity on the dynamics of phosphorous inputs on these ecosystems. In this study, we determined the association between 12 morphological plant functional traits and the movement of water-driven orthophosphate from the canopy into the soil in 20 individuals of five tree species, on single individuals scattered across a human-disturbed montane landscape in the Colombian Andes: Croton magdalenensis, Andesanthus lepidotus, Vismia baccifera and Quercus humboldtii and a commonly planted exotic species Eucalyptus globulus. We quantified PO4-P concentrations in precipitation, throughfall and stemflow in all trees for 14 isolated rainfall events. In general, our results show a general enrichment of PO4-P concentration in the net precipitation after passing through tree canopies. One particular species, C. magdalenensis, an ecological pioneer, had notably higher values of PO4-P concentration. This condition relates, potentially, to a particularly higher epiphyte load, high leaf area and high trichome density. This condition potentially facilitates biogeochemical exchange and improves ecological functions associated with early stages of forest recovery (where pioneer species dominate forest composition). Our results are particularly relevant given that the highest contributions of PO4-P to the soil occur in native species, which become key structures in the recovery of fragmented Andean ecosystems.