Effects of Forest Restoration Activities on the Bird Community of a Degraded Upland Watershed

ABSTRACT: A survey of bird species richness was carried out in a degraded upland watershed at Ban Mae Sa Mai in Doi Suthep-Pui National Park, comparing plots where forest restoration activities had started 6 months previously with control plots. Plots undergoing forest restoration had been planted with 29 "framework" tree species in June 1998. The non-planted control plots were abandoned agricultural areas, undergoing natural regeneration. Herbaceous weeds dominated these plots. Both plots had been burnt before tree planting took place and both were surveyed for birds in December 1998. In addition, a survey of birds feeding in fruiting trees in climax evergreen forest was carried out to help determine which bird species might be involved in dispersing seeds from forest to deforested areas and to identify bird species typical of the later stages or climax stage of forest succession.

In the planted plots, 16 bird species were observed. The most common species was the Grey-breasted Prinia (Prinia hodgesonii). In the non-planted plots 33 species were observed. The most common species also included the Grey-breasted Prinia (Prinia hodgesonii) as well as the Red-whiskered Bulbul (Pycnonotus jacosus). In evergreen forest, the most common species was the Black-crested Bulbul (Pycnonotus melanicterus). The value of Sorensen's index of similarity, comparing planted with non-planted plots, was 0.56, indicating a 44% difference. The two communities were, therefore, moderately different.

Low bird species richness in the planted plots was probably the result of weeding activities, necessary to allow the planted trees to grow. It is expected that bird species richness will increase, as the planted trees reach maturity and provide a greater variety of resources and niches.