การประเมินภัยคุมคาม: การเปลี่ยนแปลงสภาพอากาศ ไฟ่ป่า และภัยคุกคามอื่นๆ ของนกไต่ไม้ใหญ่ (Sitta magna) ชนิดพันธุ์ที่ใกล้สูญพันธุ์ระดับโลก

The Giant Nuthatch (Sitta magna), a bird in the family Sittidae, is restricted to southwestern China, eastern Myanmar, and northern Thailand. The global threat status of Giant Nuthatch was uplisted from vulnerable to endangered in 2012 (BirdLife International, 2020) due primarily to the loss and degradation of pine and mixed forest habitats through shifting cultivation and logging.

Giant Nuthatch, although globally endangered, is poorly known globally and lack of quantitative baseline data which is critical for effective conservation.

    Recent quantitative work in Thailand has revealed that the population of Giant Nuthatch in Thailand was approximately 578 individuals based on a density of 3.7 individuals/km² in 156 km² of suitable habitat. Giant nuthatch preferred drier forest with a large amount of mature native or planted pine (Pinus kesiya) and with a larger basal area and a more open canopy (Khamcha et al. in press). The study also revealed that Giant nuthatch has disappeared from some parts of its Thai range, although more than 90% of the suitable habitat of Giant nuthatch in Thailand was already in the protected area system, thus extensive forest loss while a serious threat in Myanmar and possibly China, but in Thailand this is less of an issue. The bigger concern for Giant Nuthatch in Thailand is the changes in habitat structure from its preferred habitat (open and well-spaced mature pine forest, perhaps previously maintained by occasional fires) to less preferred wetter and denser habitats, perhaps also partly related to climate change. Thailand has developed the first quantitative baseline data for the species (Khamcha et al. in press), a critical first step for effective conservation, however additional studies on the threats especially those related to climate change, specifically the impacts of forest fire and level of rainfall, which may influence vegetation structure are needed to understand and implement specific management actions in key sites. 

The main results from this study will provide quantitative baseline data on the main threats to Giant Nuthatch in Thailand and to clarify the potential threats that may account for their disappearance from some parts of its historical range. The results will be provided to and discussed with the Department of National Parks, Wildlife and Plant Conservation (DNP) and to work with the DNP and other organizations (such as the Bird Conservation Society of Thailand) on a further larger project to monitor the threats and to improve the policy and develop management plans for Giant Nuthatch in Thailand.