Epsilon Open Archive

Abstract

Tropical montane cloud forests (TMCFs) are covered in clouds and fog, by definition, and are abundant with mosses, lichens and epiphytes. The hydrology of these ecosystems is poorly understood due to the extreme wetness, complex topography, and remoteness, TMCF are also susceptible to several types of disturbance. The two main objectives of this thesis were to (i) study the fire history in a TMCF and (ii) investigate the changes in water input in a secondary TMCF. Field studies were conducted in southern Mexico and northern Costa Rica. The Chimalapas region of Oaxaca, Mexico was subjected to fires during the El Niño events of 1997 to 1998. Previous fires were evident from charcoal, which was collected in soil pits. Radiocarbon dating indicated that at least nine fire episodes have occurred in this area during the past 10, 000 years and the findings suggest that there have been repeated fires in the investigated TMCFs. The Costa Rican study aimed to estimate total soil water input from horizontal rain and fog (HP) in the edge and interior of a secondary TMCF. Net capture was defined as HP that reached the soil and was calculated as throughfall + stemflow - vertical precipitation. Over the 11-month measurement period, accumulated net capture decreased linearly from the forest edge (ca. 1200 mm) to the centre of the plot which was 20 m into the forest (ca.-1900 mm). Sixty-eight percent of the variability in weekly net capture could be explained by the plot position and the seasonal variation in HP input. In conclusion, the study demonstrated the potential to manage edges and emergent trees in landscapes with secondary TMCF for improved water input.