Anthropogenic land‐use change shapes bird diversity along the eastern Himalayan altitudinal gradient

Globally, the conversion of natural forest into agricultural land and
human settlement has altered avian diversity and structure often leading
to functional and/or phylogenetic homogenisation. While the effects of
land-use change on avian functional and phylogenetic diversity is well
studied in the tropics, it is poorly understood and scarcely studied in
the Himalayas, let alone in the eastern Himalayan bird communities. This
dataset comprises observations of 336 bird species from a replicated
point-count transect survey conducted between 2019 and 2020 in Bhutan. We
used a multispecies occupancy model to estimate occupancy probability
while accounting for detection probability. The detection-corrected
z-matrix was used to calculate functional and phylogenetic
diversity.  Our study shows that bird community occupancy along
the elevational gradient is negatively associated with human land use
(agriculture and settlement). Bird assemblages were functionally and
phylogenetically clustered at higher elevations. Agriculture and
settlement harboured higher functional and phylogenetic diversity whereas
forests had phylogenetically diverse communities within functionally
convergent traits. The higher functional and phylogenetic diversity in
agriculture and settlement suggests that bird diversity offers an
opportunity for a broad range of ecosystem services. Protection of forests
abutting human settlements and agriculture will help preserve higher
phylogenetic diversity. We recommend that agricultural practices that
safeguard and improve bird-friendly habitats should be promulgated.
Educational programmes on the importance of the roles of birds should be
implemented and integrating bird conservation with farm
production will help conserve bird diversity in human-dominated
landscapes. To enhance the conservation value of working landscapes in the
Himalayas, avitourism can be explored further.

全球范围内，天然林被转化为农用地与人类聚居地的活动，已改变了鸟类多样性与群落结构，往往引发功能与（或）系统发育均质化。尽管土地利用变化对鸟类功能多样性与系统发育多样性的影响在热带地区已得到充分研究，但在喜马拉雅山区，此类研究仍极为匮乏且认知不足，东喜马拉雅的鸟类群落相关研究更是少之又少。本数据集包含2019至2020年间在不丹开展的重复样点计数样线调查中记录的336种鸟类观测数据。本研究采用多物种占用模型（multispecies occupancy model），在兼顾检测概率的前提下估算占用概率。研究人员采用检测校正后的Z矩阵（detection-corrected z-matrix）计算功能多样性与系统发育多样性。本研究结果显示，沿海拔梯度分布的鸟类群落占用率与人类土地利用类型（农用地与聚居地）呈负相关关系。高海拔区域的鸟类群落呈现功能与系统发育聚集特征。农用地与聚居地承载的功能多样性与系统发育多样性更高，而森林群落虽具有功能趋同性状，但其系统发育多样性更为丰富。农用地与聚居地较高的功能与系统发育多样性表明，鸟类多样性可为多类生态系统服务提供支撑。保护毗邻人类聚居地与农用地的森林，将有助于维持更高水平的系统发育多样性。本研究建议推广能够保护并改善益鸟栖息地的农业生产模式。应开展针对鸟类生态重要性的科普教育项目，同时将鸟类保护与农业生产相结合，这将有助于在人类主导的景观中维持鸟类多样性。为提升喜马拉雅山区生产性景观的保护价值，可进一步探索观鸟旅游（avitourism）的发展路径。