Simulated drought regimes reveal community resilience and hydrological thresholds for altered decomposition

Abstract

Future climate scenarios forecast a 10-50% decline in rainfall in Eastern Amazonia. Altered precipitation patterns may change important ecosystem functions like decomposition through either changes in physical and chemical processes or shifts in the activity and/or composition of species. We experimentally manipulated hydroperiods (length of wet:dry cycles) in a tank bromeliad ecosystem to examine impacts on leaf litter decomposition. Gross loss of litter mass over 112 days was greatest in continuously submersed litter, lowest in continuously dry litter, and intermediate over a range of hydroperiods ranging from eight cycles of 7 wet:7 dry days to one cycle of 56 wet:56 dry days. The resilience of litter mass loss to hydroperiod length is due to a shift from biologically assisted decomposition (mostly microbial) at short wet:dry hydroperiods to physicochemical release of dissolved organic matter at longer wet:dry hydroperiods. Biologically assisted decomposition was maximized at wet:dry hydroperiods falling within the range of ambient conditions (12-22 consecutive dry days) but then declined under prolonged wet:dry hydroperiods (28 and 56 dry days. Fungal:bacterial ratios showed a similar pattern as biologically assisted decomposition to hydroperiod length. Our results suggest that microbial communities confer functional resilience to altered hydroperiod in tank bromeliad ecosystems. We predict a substantial decrease in biological activity relevant to decomposition under climate scenarios that increase consecutive dry days by 1.6- to 3.2-fold in our study area, whereas decreased frequency of dry periods will tend to increase the physicochemical component of decomposition.

Phytotelm to assess bacterial multi-resistance to the antibiotics in a deep tropical forest

“…Bacterial communities inside bromeliads tanks are unique and their bacterial abundance remains stable even during drought or increased rainfall events (Benavides-Gordillo et al, 2019;Rodríguez Pérez et al, 2018). To our knowledge, there is no study of AMR from phytotelm samples of the deep understory of a tropical could forest.…”

Bacterial multi-resistance to antibiotics in water from plant cavities (phytotelms) in a deep tropical forest from Costa Rica

“…Their physicochemical and geochemical characteristics, as well as the communities of macro-and micro-organisms, and their interactions, make them suitable matrices for evaluating ecological interactions, carbon and nitrogen cycles, and environmental stresses (Benavides-Gordillo et al, 2019). Moreover, the bacterial communities within bromeliad tanks are unique, and their bacterial abundance remains stable even during drought or increased rainfall events (Rodríguez-Pérez et al, 2018;Benavides-Gordillo et al, 2019).…”