Potencialidade do uso dos anéis de crescimento aplicado a análises de temporalidade hidrológica e relação clima crescimento de espécies savânicas sazonalmente inundáveis para fins de manejo sustentável

Abstract

Brazil has about 20% of its territory occupied by wetland ecosystems (AUs) that are of great importance, since they function as shelter, source of food for various organisms, and influence the water balance, carbon cycle, stabilization of the climate among others. However, any change in the hydrological cycle can strongly affect these ecosystems, since the hydrological regime is the main driver of their ecological processes. AUs ecosystems are experiencing losses and degradations linked to human economic and population growth, involving hydroelectric, mining, deforestation for agricultural expansion and urbanization. Changes in the seasonality and amount of precipitation and temperature increases are expected in the different Climate Change Scenarios, which can seriously affect these ecosystems. However, the development of AU management and conservation strategies requires a better understanding of the ecological and hydrological processes, as well as the impacts of climate change to which these areas are subject. The Pantanal stands out as one of the largest flooded AU savannas in the world. Thus, in this work, we propose strategies and actions to promote the conservation and sustainable use of the biodiversity in these environments. In addition, we assessed the dynamics of tree growth of three species widely distributed in the Pantanal Mato-grossense. From the analysis of tree rings of Tabebuia aurea (Silva Manso) Benth. & Hook.f. and S. Moore (Bignoniaceae), which grows under a different flood regime, it was possible to model its, establish cutting cycle strategies, cut diameter and discuss the current forest management practices of this species according to the GOL (Growth Oriented Logging) both in the Northern and in the Southern of the Pantanal. We also evaluated the role of different flood regimes between the northern and southern Pantanal on the growth trajectory of T. aurea trees. In addition, this study evaluated how regional climatic variables (precipitation and temperature) and Sea Surface Temperature (SST) anomalies of the Equatorial Pacific El Niño and Tropical Atlantic affect the tree growth of Handroanthus heptaphyllus (Vell.) Mattos (Bignoniaceae) and Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae). Tree-ring analyzes show that T. aurea species present variation in tree growth rates between study sites, which should be considered in the establishment of management strategies. Rainfall, temperature, and anomalies of the Equatorial Pacific influence the growth of H. heptaphyllus and H. stigonocarpa differently in the studied sites. The results obtained in this work contrast the literature and the common sense that flooding promotes stress and consequently reduces tree growth or promote its dormancy in wetland ecosystems. In the face of this controversy, we suggest that further investigations into seasonally flooded neotropical savannas should be continued.