Browsing by Autor "Luz M. Mendizabal"

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Allocation trade‐offs dominate the response of tropical forest growth to seasonal and interannual drought
(Wiley, 2014) Christopher E. Doughty; Yadvinder Malhi; Alejandro Araujo‐Murakami; Daniel B. Metcalfe; Javier E. Silva‐Espejo; Luzmila Arroyo; Juan P. Heredia; Erwin Pardo-Toledo; Luz M. Mendizabal; Victor D. Rojas-Landivar
What determines the seasonal and interannual variation of growth rates in trees in a tropical forest? We explore this question with a novel four-year high-temporal-resolution data set of carbon allocation from two forest plots in the Bolivian Amazon. The forests show strong seasonal variation in tree wood growth rates, which are largely explained by shifts in carbon allocation, and not by shifts in total productivity. At the deeper soil plot, there was a clear seasonal trade-off between wood and canopy NPP, while the shallower soils plot showed a contrasting seasonal trade-off between wood and fine roots. Although a strong 2010 drought reduced photosynthesis, NPP remained constant and increased in the six-month period following the drought, which indicates usage of significant nonstructural carbohydrate stores. Following the drought, carbon allocation increased initially towards the canopy, and then in the following year, allocation increased towards fine-root production. Had we only measured woody growth at these sites and inferred total NPP, we would have misinterpreted both the seasonal and interannual responses. In many tropical forest ecosystems, we propose that changing tree growth rates are more likely to reflect shifts in allocation rather than changes in overall productivity. Only a whole NPP allocation perspective can correctly interpret the relationship between changes in growth and changes in productivity.
Productividad interanual e interestacional de la biomasa aérea en la Chiquitanía transicional a la Amazonía (Guarayos, Bolivia)
(2014) Erwin Pardo-Toledo; Alejandro Araujo‐Murakami; Luzmila Arroyo Padilla; Juan P. Heredia; Victor D. Rojas-Landivar; Marcio Flores-Valencia; Zamir Perez; Rebeca Sibler; Luz M. Mendizabal; Meison Vega-Martínez
The productivity, allocation and cycling of carbon in forests at the dry margin of the Amazon forest in Bolivia
(Taylor & Francis, 2013) Alejandro Araujo‐Murakami; Christopher E. Doughty; Daniel B. Metcalfe; Javier E. Silva‐Espejo; Luzmila Arroyo; Juan P. Heredia; Marcio Flores; Rebeca Sibler; Luz M. Mendizabal; Erwin Pardo-Toledo
Background: The dry transitional forests of the southern Amazonia have received little attention from a carbon cycling and ecosystem function perspective, yet they represent ecosystems that may be impacted by global climate change in the future. Aims: To compare the full carbon cycle for two 1-ha forest plots that straddle the ecotone between humid forest and dry forest in Amazonia, ca. 100 km from Santa Cruz, Bolivia. Methods: 2.5 years of measurements of the components of net primary production (NPP) and autotrophic respiration were collected. Results: Total NPP was 15.5 +/- 0.89 Mg C ha(-1) year(-1) at the humid site and 11.27 +/- 0.68 Mg C ha(-1) year(-1) at the dry site; a total Gross Primary Production (GPP) of 34.14 +/- 2.92 Mg C ha(-1) year(-1) and 26.88 +/- 2.70 Mg C ha(-1) year(-1) at the two sites. Carbon use efficiency for both sites was higher than reported for other Amazonian forests (0.45 +/- 0.05 and 0.42 +/- 0.05). Conclusions: Drier soil conditions selected for the dry deciduous tree species which had higher leaf photosynthesis and total GPP. NPP allocation patterns were similar at the two sites, suggesting that in terms of carbon allocation, the dry forests of the southern Amazonia behave as a scaled-down version of wetter humid forests.