Walters Richard J, Hassall Mark, Telfer Mark G, Hewitt Godfrey M, Palutikof Jean P
School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
Proc Biol Sci. 2006 Aug 22;273(1597):2017-23. doi: 10.1098/rspb.2006.3542.
We construct a novel individual-based random-walk model to assess how predicted global climate change might affect the dispersal rates of a temperate insect. Using a novel approach we obtained accurate field measurements of daily movements for individuals over time to parameterize our model. Males were found to move significantly further on average than females. Significant variation in movement was evident among individuals; the most dispersive individuals moved up to five (females) and seven (males) times as far on average as the least dispersive individuals. Mean relative daily movement of both males and females were exponentially related to maximum daily temperature recorded within the grass sward. Variability, both within and among individuals, in relative daily movement was incorporated into the model using gamma probability distributions. Resultant dispersal functions for seasonal movement are predicted to be highly leptokurtic, which agrees well with observations from the field. Predictions of the model suggest that for populations at the polewards edge of the current range an increase of 3-5 degrees C in daily maximum temperature may increase the proportion of long-distance dispersers (those characterized as comprising the top 0.1% of furthest dispersing individuals under local conditions experienced during the 1963-1990 period) by up to 70%.
我们构建了一个全新的基于个体的随机游走模型，以评估预测的全球气候变化可能如何影响一种温带昆虫的扩散速率。我们采用一种新颖的方法，获取了个体随时间的每日移动的精确实地测量数据，用于对我们的模型进行参数化。结果发现，雄性平均移动的距离明显比雌性更远。个体之间的移动存在显著差异；扩散性最强的个体平均移动距离是扩散性最弱个体的五倍（雌性）至七倍（雄性）。雄性和雌性的平均相对每日移动与草皮内记录的最高每日温度呈指数关系。使用伽马概率分布将个体内部和个体之间相对每日移动的变异性纳入模型。预测的季节性移动的扩散函数预计具有高度的峰态，这与实地观察结果非常吻合。该模型的预测表明，对于当前分布范围极地边缘的种群，每日最高温度升高3至5摄氏度可能会使长距离扩散者（那些被定义为在1963 - 1990年期间当地条件下最远扩散个体中排名前0.1%的个体）的比例增加高达70%。
