ABSTRACT

Nest tree availability is a critical reproductive requirement for woodpeckers. To inform off-reserve management strategies for Okinawa woodpecker (OW) Dendrocopos noguchii (Syn. Sapheopipo noguchii) nest trees, we assessed the characteristics of 213 nest trees as well as the detailed forest age of the nest sites by using aerial photographs and the local forest registers. The woodpecker used 17 tree species and one tree fern. The dominant tree species used were Castanopsis sieboldii (34% of total nest trees), Melia azedarach (11%), Alnus japonica (24%), and Pinus luchuensis (8%). Castanopsis sieboldii were used most often in the forests ≥ 60 years old, while A. japonica, P. luchuensis, and M. azedarach were used most often in the younger forests. The relatively high frequency of nests in A. japonica and P. luchuensis snags was likely affected by tree die-offs due to outbreaks of the introduced leaf beetle Plagiosterna formosana and pine wilt disease caused by the introduced Pine wood nematode Bursaphelenchus xylophilus, respectively. However, these die-offs were temporary, and snags created by exotic pest outbreaks may not be long-lasting resources in the warm, humid climate. To ensure the stable supply of available nest trees for the OW, we recommend preserving areas of forest ≥ 60 years old, retaining a few C. sieboldii trees when logging, and also retaining most regenerating M. azedarach trees during thinning operations in young forests.

摘要

巢树的可用性是啄木鸟繁殖的关键要求。通知关闭储备管理战略冲绳啄木鸟（OW）斑啄木鸟noguchii（SYN。Sapheopipo noguchii）巢树，我们通过使用航拍照片和局部评估的213个巢树以及鸟巢网站的详细林龄的特点森林登记册。啄木鸟使用了17种树种和1棵树蕨。所使用的优势树种为Cast锥栗（占巢树的34％），a子草（11％），（木（24％）和绿松（8％）。锥栗在60岁以上的森林中使用最频繁，而A. japonica，P。luchuensis和M. azedarach在年轻的森林中使用最频繁。在巢的频率比较高A.粳稻和P.琉球断枝很可能影响树的相继死亡，由于引入了叶甲疫情Plagiosterna枫香，并引起推出松材线虫松材线虫病松材线虫， 分别。但是，这些死亡只是暂时的，在温暖潮湿的气候下，外来害虫暴发所造成的阻碍可能不是持久的资源。为确保OW可用巢树的稳定供应，我们建议保留≥60年的森林区域，伐木时保留几棵西伯利亚。木，并在幼林中进行伐木操作时保留大多数可再生的M. azedarach树。