Data from: Early warning indicators of population collapse in a seasonal environment

Bi-seasonal (breeding, b, and non-breeding, nb) abundances (count) from experimental population of Drosophila melanogaster exposed to chronic season-specific habitat loss. Populations were exposed to habitat loss in either the breeding or non-breeding period (seasonT), and were subject to one of two rates of loss: 10% or 20% per generation (lossT). In addition, a subset of individuals were measured from half of the replicate populations (rep; treat_rep). From each individual, measures of locomotion (activity; crosses) were collected using a Drosophila activity monitor, in which the movements of individual flies are autonomously recorded using infrared light beams. These individuals were then frozen, dried, and weighed (weight).
See readme.txt for definitions of variables in both datasets.

The abundance data has been used to determine whether populations losing breeding and non-breeding habitat decline in different ways and whether the season of decline is detectable in simple vital rates. By combining the abundance and phenotype data, we explored whether the production of trait-based early warning indicators of population collapse differs between populations losing breeding and non-breeding habitat.

本数据集包含长期暴露于季节性特异性栖息地丧失胁迫的黑腹果蝇（Drosophila melanogaster）实验种群的两季（繁殖季b与非繁殖季nb）丰度（计数）数据。实验种群分别在繁殖季或非繁殖季遭遇栖息地丧失（seasonT），且设置了两种丧失速率：每世代10%或20%（lossT）。此外，从半数重复种群（rep；treat_rep）中选取部分个体开展测量。针对每只个体，通过果蝇活动监测仪（Drosophila activity monitor）采集其运动能力数据（活动水平；跨动次数crosses）——该设备通过红外光束自动记录单只果蝇的运动轨迹。随后对上述个体进行冷冻、干燥处理并测定其体重（weight）。
两个数据集的变量定义详见readme.txt文件。
丰度数据已被用于验证：遭遇繁殖季与非繁殖季栖息地丧失的种群，其种群下降模式是否存在差异，且栖息地丧失的季节特征是否可通过简单生命率（vital rates）得以检测。结合丰度与表型数据（phenotype data），本研究进一步探讨了基于性状的种群崩溃早期预警指标（early warning indicators）的生成效果在繁殖季与非繁殖季栖息地丧失的种群间是否存在差异。