Effects of Amazonian flying rivers on frog biodiversity and populations in the Atlantic rainforest.

Given the speed at which humans are changing the climate, species with high degrees of endemism may not have time to avoid extinction through adaptation. We investigated through teleconnection analysis the origin of rainfall that determines the phylogenetic diversity of rainforest frogs and the effects of microclimate differences in shaping the morphological traits of isolated populations (which contribute to greater phylogenetic diversity and speciation). We also investigated through teleconnection analysis how deforestation in Amazonia can affect ecosystem services that are fundamental to maintaining the climate of the Atlantic rainforest biodiversity hotspot. Seasonal winds known as flying rivers carry water vapor from Amazonia to the Atlantic Forest, and the breaking of this ecosystem service could lead Atlantic Forest species to population decline and extinction in the short term. Our results suggest that the selection of morphological traits that shape Atlantic Forest frog diversity and their population dynamics are influenced by the Amazonian flying rivers. Our results also suggest that the increases of temperature anomalies in the Atlantic Ocean due to global warming and in the Amazon forest due to deforestation are already breaking this cycle and threaten the biodiversity of the Atlantic Forest hotspot.

Efectos de los ríos voladores de la Amazonía sobre la diversidad y las poblaciones de ranas en la Mata Atlántica Resumen Con la velocidad a la que la humanidad está alterando el clima, puede que las especies con un nivel elevado de endemismo no cuenten con tiempo suficiente para adaptarse y evitar la extinción. Usamos un análisis de teleconexión para investigar el origen de las precipitaciones que determinan la diversidad filogenética de las ranas selváticas y los efectos de las diferencias microclimáticas sobre la determinación de las características morfológicas de las poblaciones aisladas, las cuales contribuyen a una mayor especiación y diversidad filogenética. También utilizamos este análisis para investigar cómo la deforestación en la Amazonía puede afectar los servicios ambientales que son fundamentales para mantener el punto caliente de biodiversidad que es la Mata Atlántica. Los ríos voladores son vientos estacionales que transportan vapor de agua desde la Amazonía hasta la Mata Atlántica; la interrupción de este servicio ambiental podría derivar en la declinación poblacional y la extinción a corto plazo de las especies en este ecosistema. Nuestros resultados sugieren que los ríos voladores de la Amazonía influyen sobre la selección de las características morfológicas que determinan la diversidad de ranas y sus dinámicas poblacionales en la Mata Atlántica. Nuestros resultados también sugieren que el incremento de anomalías térmicas en el Océano Atlántico, causadas por el calentamiento global, y en la Amazonía, causadas por la deforestación, ya están interrumpiendo este ciclo y son una amenaza para la biodiversidad del punto caliente que es la Mata Atlántica.

Analysis of South American climate and teleconnection indices.

Oceanic heat anomalies affect climate in remote regions through the atmospheric cycle. South America (SA) was the first region found associated with EI Niño, which affects the fishery, agriculture, forestry, and livestock industry of SA. As approximately 60% of the total water is used for agriculture, climate changes in SA caused by ocean anomalies have led to the variability of available water, especially for irrigation water. Where the precipitation is low and/or the temperature is high, the availability and quality of water resources are under pressure. For instance, droughts associated with La Niña severely limited water supply and irrigation requirements between 25°S - 40°S in west-central Argentina and central Chile. In order to study the relationship between ocean variability and the climate of SA, 19 teleconnection indices (TI) related to Ocean abnormity are considered. The 19 indices are: the sea surface temperature (SST) and their anomaly in 4 Niño regions (SST1 + 2, SST3, SST3.4, SST4, ANOM1 + 2, ANOM3, ANOM3.4, ANOM4), Southern Oscillation Index (SOI), Oceanic Niño Index (ONI), Outgoing Longwave Radiation (OLR), Arctic Oscillation (AO), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), Pacific-North America (PNA), Atlantic Multi-decadal Oscillation (AMO), West and East of Indian Ocean Dipole (IODW, IODE), and the difference between IODW and IODE (IODd). High-resolution gridded climate data (1982-2016) from the Global Precipitation Climatology Centre (GPCC), the Climate Prediction Center (CPC), and the National Centers for Environmental Prediction (NCEP) are applied for correlation analyses. The results show that the 89.4% area of South American climate has a significant correlation with the SST in Niño region 1 + 2, the mean correlation coefficient is 0.55 for NCEP precipitation and 0.54 for CPC temperature. The lag duration for the remote correlation is around 2-3 months. It is the first attempt to analyze the correlation relationship based on 19 TIs, which can provide comprehensive insight into the climate of SA at a high-resolution scale. These findings are helpful for identifying the sensitive factors that affect climate in SA, for projecting the climate variables of SA, and for managing the irrigation water resources of SA.

Impacts of teleconnection patterns on South America climate.

Oceanic heat sources disturb the atmosphere, which, to come back to its initial state, disperses waves. These waves affect the climate in remote regions, characterizing the teleconnection patterns. In this study, we describe eight teleconnection patterns that affect South America climate: the El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO), the Tropical Atlantic Dipole (TAD), the South Atlantic Dipole (SAD), the Southern Annular Mode (SAM), the Madden-Julian Oscillation (MJO), and the Indian Ocean Dipole (IOD). Precipitation and winds at 850-hPa anomalies, considering these teleconnection patterns in ENSO neutral periods, are also presented. Overall, southeastern South America and the north sector of the North and Northeast regions of Brazil are the most affected areas by the teleconnection patterns. In general, there is a precipitation dipole pattern between these regions during each teleconnection pattern.

Revisiting remote drivers of the 2014 drought in South-Eastern Brazil.

South-Eastern Brazil experienced a devastating drought associated with significant agricultural losses in austral summer 2014. The drought was linked to the development of a quasi-stationary anticyclone in the South Atlantic in early 2014 that affected local precipitation patterns over South-East Brazil. Previous studies have suggested that the unusual blocking was triggered by tropical Pacific sea surface temperature (SST) anomalies and, more recently, by convection over the Indian Ocean related to the Madden-Julian Oscillation. Further investigation of the proposed teleconnections appears crucial for anticipating future economic impacts. In this study, we use numerical experiments with an idealized atmospheric general circulation model forced with the observed 2013/2014 SST anomalies in different ocean basins to understand the dominant mechanism that initiated the 2014 South Atlantic anticyclonic anomaly. We show that a forcing with global 2013/2014 SST anomalies enhances the chance for the occurrence of positive geopotential height anomalies in the South Atlantic. However, further sensitivity experiments with SST forcings in separate ocean basins suggest that neither the Indian Ocean nor tropical Pacific SST anomalies alone have contributed significantly to the anomalous atmospheric circulation that led to the 2014 South-East Brazil drought. The model study rather points to an important role of remote forcing from the South Pacific, local South Atlantic SSTs, and internal atmospheric variability in driving the persistent blocking over the South Atlantic.