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The Valdivian rainforest ecoregion in Chile (35°-48°S) has a high conservation priority worldwide. These forests are also keys for social welfare as a result of their supply of timber as well as ecosystem services. Forests in the ecoregion have been extensively converted to fast growing Pinus radiata and Eucalyptus spp. plantations for timber production promoted by public policies and timber companies. This study describes the results of detailed measurements of hydrology and stream water chemistry in eight small watersheds in south central Chile, subjected to replacement of native temperate rainforest by exotic Eucalyptus plantations. In this system, watersheds have streamside buffers of native forest (SNFW) with varying widths. Results indicate that retention of SNFW counteracts hydrologic effects of Eucalyptus plantations, which are widely known to reduce water yields. A 1.4% rate of increase of the run-off coefficient for each metre of increase of SNFW was observed. In addition, a decrease in the concentrations of total nitrogen, dissolved inorganic nitrogen (DIN), nitrate-N, and different sized fractions of particulate organic matter were found in streams draining these plantations as a function of increasing SNFW. Streamside buffer widths of 17-22 m for total nitrogen and DIN concentrations and ≥36 m for sediments were required to provide comparable values to reference watersheds (100% native forest). The findings from this study suggest that SNFW may significantly reduce adverse effects from exotic species forestry plantations on water provision in an area of south central Chile where exotic forest plantations are rapidly expanding.

South America is experiencing rapid change in forest cover, of both native and planted forest. Forest cover loss is primarily attributable to fire, logging, and conversion of native forest to agriculture, pasture, and forest plantations, and types of change vary within and among the many diverse types of forests in South America. Major changes in forest cover and growing policy concerns underscore an urgent need for research on sustainable forest management and water ecosystem services in South America. Differences in land ownership and management objectives create trade‐offs between wood production and water ecosystem services from forests. Work is needed to quantify how forest change and management affect ecosystem services, such as wood production versus water provision. Current scientific understanding of forest management effects on water ecosystem services in South America has important limitations, including a scarcity of long‐term records and few long‐term integrated watershed studies. Industry, government, universities, and local communities should collaborate on integrated applied studies of forests and water. Data archiving and publically available data are required. The creation of national networks and a multi‐country South America network to identify and implement common water research protocols, share results, and explore their implications would promote common and well‐supported policies. Hydrologists working in South America are well placed to tackle the challenges and opportunities for collaborative research that will maintain the intrinsic values and water ecosystem services provided by South America's forests.

Climate change is triggering ecological responses all over the world as a result of frequent, prolonged droughts. It could also affect ecological interactions, particularly pollination and seed dispersal, which play a key role in plant reproduction. We used a tripartite interaction with a mistletoe, its pollinator and its disperser animals to gain insight into this issue. We studied flower and fruit production, and visitation rates during average (2012) and dry (2015) austral summers. Drought in our study area affected precipitation and soil water availability. Although pollinator visits did not significantly differ in these summers, during the dry summer flower and fruit production experienced an important decline, as did seed disperser visits. Also, mistletoe mortality increased from 12% in 2012 to 23% in 2015. This empirical evidence suggests that the cascade effects of climate change may indirectly be hindering ecological interactions in the Valdivian temperate rainforest ecosystem we studied. Long‐term research is essential to provide the knowledge necessary to understand how key ecological processes may be affected in a changing world.

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Diurnal variations in streamflow (DVS) have been studied in detail by underwater pressure loggers. Some of this equipment requires barometric compensation with a logger or sensor located outside the water. Studies related to this topic have not offered a critical report of the validity of patterns inferred with these instruments. While studying a forested watershed in Southern Chile (40° S), we detected a DVS when the external logger was placed 1.5 m above ground, under a marked diurnal fluctuation in air temperature (amplitude 12.4 °C) and a dampened fluctuation in stream temperature (amplitude 1.4 °C). Synchronization was apparent between air and stream temperature in a direct relationship, but the synchronization between air/stream temperature and streamflow was negative, with some hours of lag time.In laboratory experiments, when the external logger is considerably warmer than the water-level logger, depth measurements can be underestimated by up to 1.5 cm. When the opposite occurs, water depths can be overestimated by up to 0.9 cm and are large instrumental/methodological artifacts compared to the field water diurnal variation of 1.3 cm. Finally, we relocated the external logger in front of the water-level logger and inside a weir, but exposed to the air. Results confirmed the pattern previously detected in the field, but streamflow fluctuations were 19% less accentuated. We conclude that the incorrect placement of the external logger, along with an instrumental artifact, can intensify a DVS pattern. Počas dňa sme podrobne sledovali zmeny prietokov v tokoch tlakovými snímačmi, umiestnenými pod vodou. Niektoré z týchto zariadení vyžadujú barometrickú kompenzáciu snímačov, ktoré nie sú umiestnené vo vode. Štúdie z tejto oblasti obyčajne nehodnotia kriticky správnosť výsledkov meraní týmito zariadeniami. Počas meraní v zalesnenom povodí na juhu Chile (40° S), sme zistili zmeny prietokov v tokoch počas dňa, ak bol externý tlakový snímač (logger) uložený 1,5 m nad zemou, počas výrazných denných zmien teploty vzduchu (amplitúda 12.4 °C) a stlmené fluktuácie teploty vody v toku (amplitúda 1.4 °C). Synchronizácia medzi teplotami vody a vzduchu bola zrejmá, ale synchronizácia medzi teplotami vody v toku a prietokmi bola negatívna, s hodinovými posunmi voči sebe. V experimentoch v laboratóriu, keď bol externý snímač podstatne teplejší ako snímač vo vode, meranie hĺbok bolo podhodnotené až o 1,5 cm. V opačnom prípade, hĺbka hladiny vody bola nadhodnotená až o 0,9 cm a boli zistené významné inštrumentálne/metodologické artefakty v porovnaní s poľnými meraniami až o 1,3 cm. Nakoniec, externý snímač bol umiestnený pred snímač s údajmi o vodnej hladine a dovnútra prepadu, ale bol vo vzduchu. Výsledky meraní potvrdili chody prietokov namerané v teréne, ale fluktuácie prietokov boli nižšie o 19 %. Z toho vyplýva, že nesprávne umiestnenie externého snímača, spolu s prístrojovými artefaktmi, môžu intenzifikovať zmeny prietokov v tokoch počas dňa.KĽÚČOVÉ SLOVÁ: inštrumentálna analýza, metodologické artefakty, južné dažďové pra...