Data and code from: Breakdown in seasonal dynamics of subtropical ant communities with land-cover change

Concerns about widespread human-induced declines in insect populations are mounting, yet little is known about how land-use change modifies the dynamics of insect communities, particularly in understudied regions. Here, we examine how the seasonal activity patterns of ants—key drivers of terrestrial ecosystem functioning—vary with anthropogenic land-cover change on a subtropical island landscape, and whether differences in temperature or species composition can explain observed patterns. Using trap captures sampled biweekly over two years from a biodiversity monitoring network covering Okinawa Island, Japan, we processed 1.2 million individuals and reconstructed activity patterns within and across habitat types. Forest communities exhibited greater temporal variability of activity than those in more developed areas. Using time-series decomposition to deconstruct this pattern, we found that sites with greater human development exhibited ant communities with diminished seasonality, reduced synchrony, and higher stochasticity compared to sites with greater forest cover. Our results cannot be explained by variation in regional or site temperature patterns, or by differences in species richness or composition among sites. Our study raises the possibility that disruptions to natural seasonal patterns of functionally key insect communities may comprise an important and underappreciated consequence of global environmental change that must be better understood across Earth's biomes.

当前，学界对人类活动普遍引发昆虫种群下降的担忧与日俱增，但对于土地利用变化如何改变昆虫群落动态，尤其是在研究不足的区域，我们仍知之甚少。本研究以亚热带岛屿景观为研究对象，探讨作为陆地生态系统功能关键调控者的蚂蚁，其季节性活动模式如何随人为土地覆盖变化发生改变，并验证温度差异或物种组成差异能否解释观测到的活动模式。研究依托覆盖日本冲绳岛的生物多样性监测网络，在两年内每两周开展一次诱捕采样，共处理120万只蚂蚁个体，并重建了不同生境内部及生境间的活动模式。相较于开发程度更高的区域，森林生境中的蚂蚁群落活动的时间变异性更强。通过时间序列分解拆解该模式后，研究发现：相较于森林覆盖度更高的样地，人类开发程度更高的样地中，蚂蚁群落的季节性弱化、同步性降低且随机性升高。本研究结果无法通过区域或样地的温度格局变化，或是样地间物种丰富度与组成的差异来解释。本研究提示，对具有关键生态功能的昆虫群落自然季节性模式的破坏，可能是全球环境变化带来的一项重要却未被充分重视的后果，这一现象亟待在全球各生物群区中得到更深入的研究与认知。