Environmental controls on canopy foliar nitrogen distributions in a Neotropical lowland forest.

Published

Journal Article

Distributions of foliar nutrients across forest canopies can give insight into their plant functional diversity and improve our understanding of biogeochemical cycling. We used airborne remote sensing and partial least squares regression to quantify canopy foliar nitrogen (foliar N) across ~164 km2 of wet lowland tropical forest in the Osa Peninsula, Costa Rica. We determined the relative influence of climate and topography on the observed patterns of foliar N using a gradient boosting model technique. At a local scale, where climate and substrate were constant, we explored the influence of slope position on foliar N by quantifying foliar N on remnant terraces, their adjacent slopes, and knife-edged ridges. In addition, we climbed and sampled 540 trees and analyzed foliar N in order to quantify the role of species identity (phylogeny) and environmental factors in predicting foliar N. Observed foliar N heterogeneity reflected environmental factors working at multiple spatial scales. Across the larger landscape, elevation and precipitation had the highest relative influence on predicting foliar N (30% and 24%), followed by soils (15%), site exposure (9%), compound topographic index (8%), substrate (6%), and landscape dissection (6%). Phylogeny explained ~75% of the variation in the field collected foliar N data, suggesting that phylogeny largely underpins the response to the environmental factors. Taken together, these data suggest that a large fraction of the variance in foliar N across the landscape is proximately driven by species composition, though ultimately this is likely a response to abiotic factors such as climate and topography. Future work should focus on the mechanisms and feedbacks involved, and how shifts in climate may translate to changes in forest function.

Full Text

Duke Authors

Cited Authors

  • Balzotti, CS; Asner, GP; Taylor, PG; Cleveland, CC; Cole, R; Martin, RE; Nasto, M; Osborne, BB; Porder, S; Townsend, AR

Published Date

  • December 2016

Published In

Volume / Issue

  • 26 / 8

Start / End Page

  • 2449 - 2462

PubMed ID

  • 27874999

Pubmed Central ID

  • 27874999

International Standard Serial Number (ISSN)

  • 1051-0761

Digital Object Identifier (DOI)

  • 10.1002/eap.1408

Language

  • eng

Conference Location

  • United States