Jenouvrier Stephanie, Barbraud Christophe, Weimerskirch Henri
Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, F-79360 Villiers en Bois, France.
J Anim Ecol. 2003 Jul;72(4):576-587. doi: 10.1046/j.1365-2656.2003.00727.x.
Ecological and population processes are affected by large-scale climatic fluctuations, and top predators such as seabirds can provide an integrative view on the consequences of environmental variability on ecosystems. Here, we examine the dynamics of a southern fulmar population in Antarctica over a 39-year period and evaluate the impact of environmental variability on the life history traits of this top predator species. Between 1963 and 2002, the number of breeding pairs fluctuated between seven and 53 in relation to variations in sea ice concentration, and increased overall (annual growth rate: 1·0035). Breeding performance tended to be lower in years with low sea ice concentration. The proportion of birds attempting to breed varied strongly from one year to the next despite the birds were alive, indicating strong environmental forcing on the decision to breed. The number of new local recruits and immigrants was correlated highly with the number of local breeders, and capture probabilities were positively related to the breeding population size. Local recruitment, number of local breeders and proportion of birds attempting to breed were lower when sea ice concentration during summer was low. Adult survival between 1964 and 2002 was on average 0·923 ± 0·006, and decreased during years with high sea surface temperature and low sea ice concentration. Modelled population growth rate, estimated using matrix models, of the population was 0·9728, a difference of 3·6% compared to the observed rate of increase. This discrepancy is due probably to the immigration rate (3 ± 3%). Demographic parameters were affected by sea ice concentration and sea surface temperature anomalies, probably through an impact on krill availability, the main prey of southern fulmars. During warm anomalies, birds skip breeding probably because the food availability was low and limiting for the highly energy demanding reproductive activities. We also emphasize that demographic parameters were very low during the period 1975-80 and showed a higher variability after 1980, which could be interpreted in the context of a regime shift. Our study indicates that the southern fulmar population dynamics may be very susceptible to environmental variability. Further long-lasting warm anomalies are likely to affect negatively their populations.
生态和种群过程受到大规模气候波动的影响，而诸如海鸟之类的顶级捕食者能够提供关于环境变化对生态系统影响的综合观点。在此，我们研究了南极南极巨海燕种群在39年期间的动态，并评估环境变化对这种顶级捕食者物种生活史特征的影响。在1963年至2002年期间，繁殖对数在7至53对之间随海冰浓度变化而波动，总体呈增加趋势（年增长率：1.0035）。在海冰浓度低的年份，繁殖表现往往较低。尽管鸟类存活，但尝试繁殖的鸟类比例年际间变化很大，表明繁殖决策受到强烈的环境影响。新的本地招募个体和迁入个体数量与本地繁殖者数量高度相关，捕获概率与繁殖种群规模呈正相关。当夏季海冰浓度低时，本地招募个体数量、本地繁殖者数量和尝试繁殖的鸟类比例较低。1964年至2002年期间成年个体的存活率平均为0.923±0.006，在海表面温度高和海冰浓度低的年份有所下降。使用矩阵模型估计的该种群模拟种群增长率为0.9728，与观察到的增长率相差3.6%。这种差异可能是由于迁入率（3±3%）。人口统计学参数受到海冰浓度和海表面温度异常的影响，可能是通过对南极巨海燕的主要猎物磷虾可获得性的影响。在温暖异常期间，鸟类可能会跳过繁殖，原因可能是食物可获得性低，限制了对能量需求很高的繁殖活动。我们还强调，人口统计学参数在1975 - 1980年期间非常低，1980年之后变异性更高，这可以在 regime shift 的背景下进行解释。我们的研究表明，南极巨海燕种群动态可能对环境变化非常敏感。进一步长期的温暖异常可能会对其种群产生负面影响。
