دانلود رایگان مقاله رابطه شاخص سطح برگ و محیط زیست

Abstract

Land use change is a major threat to biodiversity. One mechanism by which land use change influences biodiversity and ecological processes is through changes in the local climate. Here, the relationships between leaf area index and five climate variables – air temperature, relative humidity, vapour pressure deficit, specific humidity and soil temperature – are investigated across a range of land use types in Borneo, including primary tropical forest, logged forest and oil palm plantation. Strong correlations withthe leaf area index are found for the mean daily maximum air and soil temperatures, the mean dailymaximum vapour pressure deficit and the mean daily minimum relative humidity. Air beneath canopies with high leaf area index is cooler and has higher relative humidity during the day. Forest microclimateis also found to be less variable for sites with higher leaf area indices. Primary forest is found to be up to2.5◦C cooler than logged forest and up to 6.5◦C cooler than oil palm plantations. Our results indicate thatleaf area index is a useful parameter for predicting the effects of vegetation upon microclimate, whichcould be used to make small scale climate predictions based on remotely sensed data.

5. Conclusion

We found a strong link between leaf area index (LAI) and five ecologically important climate variables in a tropical forest. This offers great potential for improved modelling of microclimate in heterogeneous landscapes, as LAI is already widely used in climate and land surface models and can be measured locally and remotely following standard methods. Human disturbance of forest systems leads to significant changes in LAI that alter the microclimate and these changes will likely have knock-on effects upon ecosystem functioning.