Ecophysiological controls on water use of tropical cloud forest trees in response to experimental drought.

Tropical montane cloud forests (TMCFs) are expected to experience more frequent and prolonged droughts over the coming century, yet understanding of TCMF tree responses to moisture stress remains weak compared with the lowland tropics. We simulated a severe drought in a throughfall reduction experiment (TFR) for 2 years in a Peruvian TCMF and evaluated the physiological responses of several dominant species (Clusia flaviflora Engl., Weinmannia bangii (Rusby) Engl.

Do Nitrogen and Phosphorus Additions Affect Nitrogen Fixation Associated with Tropical Mosses?

Tropical cloud forests are characterized by abundant and biodiverse mosses which grow epiphytically as well as on the ground. Nitrogen (N)-fixing cyanobacteria live in association with most mosses, and contribute greatly to the N pool via biological nitrogen fixation (BNF). However, the availability of nutrients, especially N and phosphorus (P), can influence BNF rates drastically.

Bryophyte stable isotope composition, diversity and biomass define tropical montane cloud forest extent.

Liverworts and mosses are a major component of the epiphyte flora of tropical montane forest ecosystems. Canopy access was used to analyse the distribution and vertical stratification of bryophyte epiphytes within tree crowns at nine forest sites across a 3400 m elevational gradient in Peru, from the Amazonian basin to the high Andes. The stable isotope compositions of bryophyte organic material (C/C and O/O) are associated with surface water diffusive limitations and, along with C/N content, provide a generic index for the extent of cloud immersion.

Isotopic values of the Amazon headwaters in Peru: comparison of the wet upper Río Madre de Dios watershed with the dry Urubamba-Apurimac river system.

Rationale: The Amazon River is a huge network of long tributaries, and little is known about the headwaters. Here we present a study of one wet tropical Amazon forest side, and one dry and cold Atiplano plateau, originating from the same cordillera. The aim is to see how this difference affects the water characteristics.

[Acute cerebellar ataxia in a 5-year-old boy. Clinical warnings].

A case of acute cerebellar ataxia caused by ECHO virus 30.5-year-old boy admitted to the Clinic of Gastroenterology and Nutrition in Warsaw, in September, 1996, complaining of headache, dizziness, weakness, somnolence, dysarthria and an unsteady walk. On neurological examination he had imparied coordination, rombergism, generalized hypotonia.