Effects of functional diversity on evapotranspiration rate: an annual analysis of three Chilean temperate forests

Abstract

There is a link between the diversity of forest ecosystems and the evapotranspiration (ET) ecosystem process. However, there is little knowledge of this link in temperate forests of southern South America. Given the influence of ET in relevant ecosystem services, such as hydrological or climatic regulation, it is important to understand the effect of the change in species composition on this process. The objective of this research was to determine the relationship between functional diversity and the seasonal variation of ET using three native forest ecosystems that differ in structure, composition of dominant species and proportion of phenological strategies as a study model. The general pattern shows that there is a significant negative relationship between the community weighted average of the specific leaf area attribute; CWM-SLA and the ET process. We found seasonal changes in ET in the three ecosystems, which was greater in spring-summer. There is a positive relationship between the percentage of evergreen species in the canopy and total annual ET of each ecosystem. This would explain the negative relationship between CWM-SLA and ET, since the ecosystem with the highest proportion of evergreen species corresponds to the one with the lowest CWM-SLA. The results of this study contribute to giving relevance to the functional diversity of native forest ecosystems over a crucial ecosystem process for the provision of various ecosystem services. Subsequent studies could assess the effect of the loss of functional diversity on ecosystem processes in order to relieve the need to conserve and/or restore the native forest from this perspective.