1 Total Net Primary Production in Forests on contrasting soils in Colombian Amazon: Does Belowground offset lower Aboveground Production in poorer soils? Eliana Jiménez, Flavio Moreno, Ma. Cristina Peñuela Diego Navarrete, Oliver Phillips Jon Lloyd, Sandra Patiño, Esteban Álvarez, Adriana Prieto & Agustín Rudas.

RAINFOR analyzed data from 120 plots and found a gradient in the growth rates of trees WOOD PRODUCTIVITY IN AMAZONIA They proposed the hypothesis: there is a relationship between wood productivity and soil fertility Variation of growth rate in the Amazon basin (Malhi et al. 2004) 2

3 HYPOTHESIS “Differential allocation hypothesis” an increase in total NPP due to a resource availability increases is followed by an increase in the proportion of NPP allocated to foliage and wood, and a decrease in the proportion allocated to fine roots (Hendricks et al. 1993, Gower et al. 1992; Albaugh et al. 1998; Tateno et al. 2004, Aber et al. 1985; Nadelhoffer et al. 1985; Raich & Nadelhoffer 1989)

SITE DESCRIPTION Colombian Amazon AMACAYACU NATURAL NATIONAL PARK ZAFIRE BIOLOGICAL STATION 4

AMACAYACU NATURAL NATIONAL PARK Forest on clay soils Two 1-ha plots: AME y AMU Agustín Rudas & Adriana Prieto 225 y 244 tree species per ha 647 y 606 stems per ha FOREST TYPES ZAFIRE BIOLOGICAL STATION Forest on white sands ( Hard pan cm of soil depth) One 1-ha plot: ZAB Ma. Cristina Peñuela & Esteban Álvarez 64 tree species per ha 866 stems per ha 5

6 Patterns in rainfall monthly, mean monthly multiannual ( ) and mean temperature (Airport Vásquez Cobo Meteorological Station, Leticia, Amazonas, Colombia). CLIMATE DRY MONTHS: JUN-AUG= 177,17 mm RAIN MONTHS : JAN-APR= 353,66 mm Monthly Precipitation Mean Precipitation Mean Temperature Precipitation (mm) Temperature (C °)

7 1. Growth rate of stems DBH≥10 cm 2. Litterfall 25 Tramps/ha ABOVEGROUND

8 Fine root (≤2 mm) Mass and Production By two direct methods (Vogt et al., 1998) : 1. Ingrowth bags  sub areas of sample per ha (each 40 m inside of plot)  Three dates of establishment:  Establishment 1: February of 2004 (AMA)  Establishment 2: September of 2004 (AMA y ZAB)  Establishment 3: February of 2006 (AMA y ZAB)  Monitored every 3 months 2. Sequential cores  13 cores per ha  Monitored every 3 months BELOWGROUND

9 RESULTS AND DISCUSSION 9

** 10 Forest on white sands – Zafire Stat. Forest on clay soils – PNN Amacayacu Accumulated fine root mass (Mg ha -1 ) * * * * * * * * Establishment 1. Feb-2004 Establishment 2. Sep-2004 ** ACCUMULATED FINE ROOT MASS 10

11 FINE ROOT MASS AND PRODUCTION SEQUENTIAL CORES METHOD FINE ROOT MASS AND PRODUCTION SEQUENTIAL CORES METHOD Soil depth (cm) a b c a b c a b c Average fine root mass (Mg ha -1 ) during the monitoring time (2,2 years) Fine root production (Mg ha -1 año -1 ) a a b a b a a b 11

12 Mean Production (0-20 cm) FINE ROOT PRODUCTION INGROWTH BAGS METHOD FINE ROOT PRODUCTION INGROWTH BAGS METHOD Forest on clay soils Forest on white sands a b 12

13 Precipitation anomaly, evaluated as the difference between the monthly precipitation and the mean monthly precipitation ( ). Relative Growth Rate (RGR) before, during and after the dry period in 2005 AME AMU ZAB ¿Did the dry season of 2005 affect Fine root production? Precipitation anomaly (mm) 13

Stems Litter TOTAL Ingrowth Sequential 14 Aboveground Productivity Production (Mg C ha -1 año -1 ) Litterfall Productivity: Navarrete (2006) Stem Productivity: Jiménez et al., (data no publ.) ABOVEGROUND AND BELOWGROUND C PRODUCTION 14 Belowground Productivity (fine roots)

15 TOTAL CARBON ALLOCATION – Total NPP Mg C ha-1 year-1

Thanks! A lot of people help during this research. Indigenous Community of Palmeras Indigenous Community of San Martín de Amacayacu Indigenous Community of Km 6 Natural National Park Amacayacu RAINFOR 16

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