PELD Tanguro Ranch - Brazil
PELD Tanguro Ranch
tropical forest ecosystem
tropical lowland evergreen rainforest
Tanguro Ranch is located in the southern Amazon, the driest portion of the Amazon Basin, and harbors a transitional forest (between Amazon forests and savannas). Tanguro lies on the Amazonian agricultural frontier, where largest rates of deforestation and fire occurred in last decades. The ranch experienced deforestation for cattle pasture in the mid-1980s, followed by a cropland expansion in the early 2000s. Starting in 2010, it has undergone a rapid shift from soybean single cropping to soybean-corn double cropping. The topography, soils, hydrology and farming practices at Tanguro are typical of the southern and eastern Amazonian agricultural frontier, a region that is highly vulnerable to changes in fire regime, climate change, and their interactions. Tanguro ranch represents changes that occur in a much wider area and that will probably occur in other regions of the Amazon Basin in a near future.
General Characteristics, Purpose, History
Land-use changes have altered the dynamics, structure and functioning of semideciduous seasonal forests in the Amazonian agricultural frontier. Such changes impact local and regional climate through disruptions of hydrological, carbon and energy cycles, with cascading effects that threaten regional biodiversity and the health of streams. Although these effects persist for decades, and interact with global climate changes, the possible trajectories of forests and aquatic environments remain poorly understood in the Amazon agricultural frontier, as well as its impacts on biodiversity and ecosystem services and functions it performs. This is largely due to the lack of studies capable of assessing the extent to which terrestrial and aquatic ecosystems are changed within fragmented landscapes and under high pressure of large-scale agricultural in the long-term. We aim to answer the following questions: (1) What are the long-term impacts of the interaction among forest fragmentation, climatic extremes and fire disturbances in the structure, diversity and functioning of Amazon-Cerrado transitional forests? (2) To what extent are the forests located on the agricultural frontier resilient to multiple disturbances, and what are the consequences for ecosystem processes and for local and regional biodiversity? (3) Are deforestation and degradation of tropical forests already changing the balance of water and energy much faster than expected, due to increased greenhouse gas emissions? Such changes would be higher during a dry season and years of severe drought? Are deforestation and land-use change modifying the hydrological regime in the basin scale? How these changes affect ecosystem processes of terra-firme forests, and how they would affect riparian forests? (4) What are the roles of riparian forests in maintaining the integrity of ecosystems in agricultural landscapes?
Tanguro site was established in 2004, for the largest fire experiment in tropical rain forests to investigate the impacts of recurrent fire in southern Amazon. We established three adjacent plots of 50-ha each – an annually burnt (six times in 7 years), a triennial burnt (three times in 7 years) and an unburned control. All fires were conducted near the end of the dry season, when fires associated to land-use changes escape to adjacent forest more often. Before experimental burning, several vegetation (e.g. as species richness, relative abundance of the five most common species, Importance Value Index (IVI), adult composition, woody stem density and composition, stem regeneration density) and microclimate variables (e.g. vapor pressure deficit near the soil surface and litter moisture content) were measured in all three plots as a baseline. Also, we conducted several measurements before, during, and after the fire to capture the fuel and microclimate drivers of fire behavior (see Balch et al. 2015 for a full description and overall results). Since then, we have collected data ecological and climatological in the region. After the establishment of the site for the long-term experimental fire project, several parallel projects have been conducted in the site, either complementing dataset regarding this experiment and others. These include studies investigating the roles of long-term fire in habitat conversion (Silvério et al. 2013), the interactions of extreme weather events with recurrent fires (Brando et al. 2014), and overall impacts of land-use change in aquatic ecosystems (e.g. Macedo et al. 2013; Neil et al. 2013), climate and feedbacks (e.g. Coe et al. 2013), In 2013 we established another fire experiment in a nearby area within our research site, where we manipulated fine fuel loads to isolate the effects of fuel loads on fire behavior and fire-induced changes in forest carbon cycling (Brando et al. 2016), and to investigate the impacts on associated fauna and their ecosystem functions (Paolucci et al. 2016). As for the first fire experiment, several measures were taken before, during and are still taken after fires. Moreover, we burned the same areas again in 2016, to investigate potential cumulative effects of fire and the interaction with fuel availability on variables we measured. References: Balch, J.K., Brando, P.M., Nepstad, D.C., Coe, M.T., Silvério, D., Massad, T.J., Davidson, E.A., Lefebvre, P., Oliveira-Santos, C., Rocha, W., 2015. The susceptibility of southeastern Amazon forests to fire: insights from a large-scale burn experiment. Bioscience 65, 893-905. Brando, P.M., Balch, J.K., Nepstad, D.C., Morton, D.C., Putz, F.E., Coe, M.T., Silvério, D., Macedo, M.N., Davidson, E.A., Nóbrega, C.C., Alencar, A., Soares-Filho, B.S., 2014. Abrupt increases in Amazonian tree mortality due to drought-fire interactions. Proc. Natl. Acad. Sci. USA 111, 6347-6352. Brando, P.M., Oliveria-Santos, C., Rocha, W., Cury, R., Coe, M.T., 2016. Effects of experimental fuel additions on fire intensity and severity: unexpected carbon resilience of a neotropical forest. Global Change Biol. 22, 2516–2525. Macedo, M.N., Coe, M.T., DeFries, R., Uriarte, M., Brando, P.M., Neill, C., Walker, W.S., 2013. Land-use-driven stream warming in southeastern Amazonia. Phil. Trans. R. Soc. B 368, 20120153. Neill, C., Coe, M.T., Riskin, S.H., Krusche, A.V., Elsenbeer, H., Macedo, M.N., McHorney, R., Lefebvre, P., Davidson, E.A., Scheffler, R., 2013. Watershed responses to Amazon soya bean cropland expansion and intensification. Phil. Trans. R. Soc. B 368, 20120425. Paolucci, L.N., Maia, M.L.B., Solar, R.R.C., Campos, R.I., Schoereder, J.H., Andersen, A.N., 2016. Fire in the Amazon: impact of experimental fuel addition on responses of ants and their interactions with myrmecochorous seeds. Oecologia 182, 335-346. Silvério, D.V., Brando, P.M., Balch, J.K., Putz, F.E., Nepstad, D.C., Oliveira-Santos, C., Bustamante, M.M.C., 2013. Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses. Philos. Trans. R. Soc. Lond., Ser. B: Biol. Sci. 368, 20120427.
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