14 Oct 2022
 | 14 Oct 2022
Status: a revised version of this preprint is currently under review for the journal BG.

Throughfall exclusion and fertilization effects on tropical dry forest tree plantations, a large-scale experiment

German Vargas G., Daniel Perez-Aviles, Nannette Raczka, Damaris Pereira-Arias, Julián Tijerín-Triviño, L. David Pereira-Arias, David Medvigy, Bonnie G. Waring, Ember Morrisey, Edward Brzostek, and Jennifer S. Powers

Abstract. Across tropical ecosystems, global environmental change is causing drier climatic conditions and increases in nutrient depositions. Such changes represent large uncertainties due to unknown interactions between drought and nutrient availability in controlling ecosystem net primary productivity (NPP). Using a large-scale manipulative experiment, we studied whether nutrient availability affects the responses of three component NPP fluxes (stem growth, fine roots production, and litterfall) to through-fall exclusion in 30-year-old unmanaged mixed plantations of six tree species native to the tropical dry forest of Costa Rica. We used a factorial design with four treatments: control (CN), fertilization (F), drought (D), and drought+fertilization (D+F). While we found that a 13–15 % reduction in soil moisture only led to modest effects in the studied ecosystem processes, NPP increased as a function of F and D+F. At the same time, NPP increases with nutrient additions were larger in the plots without throughfall exclusion. The relative contribution of each biomass flux to NPP varied depending on the treatment, with woody biomass being more important for F and root biomass for D+F and D. Moreover, seasonal canopy cover was maintained longer in the fertilized plots. Belowground processes such as nodulation and microbial carbon use efficiency (CUE) also responded to experimental treatments, with a decrease in nodulation for F plots and an increase in CUE for F and D plots. Species functional type (i.e., N-fixation or deciduousness) and not the experimental manipulations were the main source of variation in tree relative growth rates. Our results emphasize that nutrient availability moderately constrains ecosystem processes in tropical dry forests, but this depends on water availability.

German Vargas G. et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on bg-2022-203', Anonymous Referee #1, 03 Nov 2022
    • AC1: 'Comment on bg-2022-203', German Vargas, 17 Dec 2022
  • RC2: 'Comment on bg-2022-203', Anonymous Referee #2, 04 Nov 2022
    • AC2: 'Reply on RC2', German Vargas, 17 Dec 2022
  • AC1: 'Comment on bg-2022-203', German Vargas, 17 Dec 2022

German Vargas G. et al.

German Vargas G. et al.


Total article views: 416 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
299 103 14 416 30 4 5
  • HTML: 299
  • PDF: 103
  • XML: 14
  • Total: 416
  • Supplement: 30
  • BibTeX: 4
  • EndNote: 5
Views and downloads (calculated since 14 Oct 2022)
Cumulative views and downloads (calculated since 14 Oct 2022)

Viewed (geographical distribution)

Total article views: 424 (including HTML, PDF, and XML) Thereof 424 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 24 Mar 2023
Short summary
To study whether nutrient availability controls tropical dry forest responses to reductions in soil moisture, we established the first trough-fall exclusion experiment in a tropical dry forest plantation system crossed with a fertilization scheme. We found that the effects of fertilization on net primary productivity are larger than the effects of a ~15 % reduction in soil moisture. Although in many cases we observed an interaction between drought and nutrient additions, suggesting co-limitation.