Seasonal production, allocation and cycling of carbon in two mid-elevation tropical montane forest plots in the Peruvian Andes

Background: Tropical montane cloud forests (TMCF) are unique ecosystems with high biodiversity and large carbon reservoirs. To date there have been limited descriptions of the carbon cycle of TMCF.Aims: We present results on the production, allocation an

Productivity and carbon allocation in a tropical montane cloud forest in the Peruvian Andes

Background: The slopes of the eastern Andes harbour some of the highest biodiversity on Earth and a high proportion of endemic species. However, there have been only a few and limited descriptions of carbon budgets in tropical montane forest regions.Aims

Herbivory makes major contributions to ecosystem carbon and nutrient cycling in tropical forests

Abstract The functional role of herbivores in tropical rainforests remains poorly understood. We quantified the magnitude of, and underlying controls on, carbon, nitrogen and phosphorus cycled by invertebrate herbivory along a 2800 m elevational gradient in the tropical Andes spanning 12°C mean annual temperature. We find, firstly, that leaf area loss is greater at warmer sites with lower foliar phosphorus, and secondly, that the estimated herbivore-mediated flux of foliar nitrogen and phosphorus from plants to soil via leaf area loss is similar to, or greater than, other major sources of these nutrients in tropical forests. Finally, we estimate that herbivores consume a significant portion of plant carbon, potentially causing major shifts in the pattern of plant and soil carbon cycling. We conclude that future shifts in herbivore abundance and activity as a result of environmental change could have major impacts on soil fertility and ecosystem carbon sequestration in tropical forests

Productivity and carbon allocation in a tropical montane cloud forest in the Peruvian Andes

<div><p> <b><i>Background:</i></b> The slopes of the eastern Andes harbour some of the highest biodiversity on Earth and a high proportion of endemic species. However, there have been only a few and limited descriptions of carbon budgets in tropical montane forest regions.</p> <p> <b><i>Aims:</i></b> We present the first comprehensive data on the production, allocation and cycling of carbon for two high elevation (ca. 3000 m) tropical montane cloud forest plots in the Kosñipata Valley, Peruvian Andes.</p> <p> <b><i>Methods:</i></b> We measured the main components and seasonal variation of net primary productivity (<i>NPP</i>), autotrophic (<i>R</i>_a) and heterotrophic (<i>R</i>_h) respiration to estimate gross primary productivity (<i>GPP</i>) and carbon use efficiency (<i>CUE</i>) in two 1-ha plots.</p> <p> <b><i>Results:</i></b><i>NPP</i> for the two plots was estimated to be 7.05 ± 0.39 and 8.04 ± 0.47 Mg C ha⁻¹ year⁻¹, <i>GPP</i> to be 22.33 ± 2.23 and 26.82 ± 2.97 Mg C ha⁻¹ year⁻¹ and <i>CUE</i> was 0.32 ± 0.04 and 0.30 ± 0.04.</p> <p> <b><i>Conclusions:</i></b> We found strong seasonality in <i>NPP</i> and moderate seasonality of <i>R</i>_a, suggesting that forest <i>NPP</i> is driven by changes in photosynthesis and highlighting the importance of variation in solar radiation. Our findings imply that trees invest more in biomass production in the cooler season with lower solar radiation and more in maintenance during the warmer and high solar radiation period.</p> </div