Data from: Species-specific responses of foliar nutrients to long-term nitrogen and phosphorus additions in a lowland tropical forest
Data files
Oct 08, 2014 version files
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Abstract
1) The concentration, stoichiometry, and resorption of nitrogen (N) and phosphorus (P) in plant leaves are often used as proxies of the availability of these growth-limiting nutrients, but the responses of these metrics to changes in nutrient availability remains largely untested for tropical forest trees. 2) We evaluated changes in N and P concentrations, N:P ratios, and resorption for 4 common tree species after 13 years of factorial N and P additions in a lowland tropical forest in Panama. 3) Chronic P addition increased foliar P concentrations, decreased P resorption proficiency, and decreased N:P ratios in three locally common eudicot tree species (Alseis blackiana, Heisteria concinna, Tetragastris panamensis). The increase in foliar P involved similar proportional increases in organic and inorganic P in two species and a disproportionately large increase in inorganic P in A. blackiana. 4) Nitrogen addition did not alter foliar N concentrations in any species, but did decrease N resorption proficiency in H. concinna. 5) A fourth species, the palm Oenocarpus mapora, demonstrated remarkably static foliar nutrient concentrations, responding only with a marginal decrease in P resorption proficiency under N plus P co-addition. 6) Synthesis: Collectively, these results suggest that adjustment of N:P ratios can be expected in eudicots exposed to elevated P, but foliar N appears to already be at optimal levels in these lowland rainforest tree species. The complexity of species-specific responses to altered nutrient availability highlights the difficulty in predicting future responses of tropical forest trees to a changing world.
GFEresorption
Data were collected in the field during the 13th year of fertilization on the Gigante Fertilization Experiment in the Barro Colorado National Monument, Republic of Panama.
Abbreviated headlines are as follows: "Blk" = Block; "Rx" = treatment; "N" = N addition; "P" = P addition; "Species" = tree species sampled; "Leaf C" = mg/g of C in dried green leaves; "Leaf N" = mg/g of N in dried green leaves; "Leaf P" = mg/g of Total P in dried green leaves; "Leaf Pi" = mg/g of Inorganic P in dried green leaves; "Leaf Po" = mg/g of Po – Pi in dried green leaves; "%Pi" = proportion of total P comprised of inorganic P; "Leaf 13C" = delta 13C values from green leaves; "Leaf 15C" = delta 15N values from green leaves; "Litter 15N" = delta 15N values from senesced leaf litter; "Litter N corr" = mass loss based correction of litter N concentration (mg/g); "litter C" = mg/g of carbon from senesced leaf litter; "litter 13C" = delta 13C values from senesced leaf litter; "litter P" = mg/g of P from senesced leaf litter; "litter P corr" = mass loss based correction of litter P concentration (mg/g); "leaf – litter 15N" = difference among green leaf and senesced litter delta 15N values; "leaf – litter N" = difference among green leaf and senesced litter N concentration (mg/g); "leaf C:N" = ratio of carbon to nitrogen in green leaves; "litter C:N" = "leaf – litter fall P" = difference among green leaf and senesced litter P concentration (mg/g); "leaf N:P" = ratio of nitrogen to phosphorus in green leaves; "litter N:P" = ratio of nitrogen to phosphorus in senesced leaves; "litter organic P" = mg/g of Po – Pi in senesced leaves; "N res" = resorption efficiency of N; "N_res_corr" = resorption efficiency of N based on mass loss corrected leaf litter N; logN_res_corr" = log transformation; "P res" = phosphorous resorption efficiency; "P_res_corr" = resorption efficiency of P based on mass loss corrected leaf litter P; "logP_res_corr" = log transformation; "N:P res" = ratio of N to P resorption efficiencies; "logN:P_res_cor" = log transformation of mass loss corrected resorption efficiency ratios; "N:P_res_corr" = mass loss corrected resorption efficiency ratios; "transformed_P" = log transformed P concentrations; "N_resorp" = N resorption efficiency with negatives removed; "P_resorp" = P resorption efficiency with negatives removed; and, "N:P_resorp" = ratio of N and P resorption efficiencies.
