Arnold Jennifer M, Brault Solange, Croxall John P
Department of Biology, University of Massachusetts, 100 Morrissey Boulevard, Boston, Massachusetts 02125, USA.
Ecol Appl. 2006 Feb;16(1):419-32. doi: 10.1890/03-5340.
Simulation modeling was used to reconstruct Black-browed Albatross (Diomedea melanophris) population trends. Close approximations to observed data were accomplished by annually varying survival rates, reproductive success, and probabilities of returning to breed given success in previous years. The temporal shift in annual values coincided with the start of longline fishing at South Georgia and potential changes in krill abundance. We used 23 years of demographic data from long-term studies of a breeding colony of this species at Bird Island, South Georgia, to validate our model. When we used annual parameter estimates for survival, reproductive success, and probabilities of returning to breed given success in previous years, our model trajectory closely followed the observed changes in breeding population size over time. Population growth rate was below replacement (lambda < 1) in most years and was most sensitive to changes in adult survival. This supports the recent IUCN uplisting of this species from "Vulnerable" to "Endangered." Comparison of pre-1988 and post-1988 demography (before and after the inception of a longline fishery in the breeding area) reveals a decrease in lambda from 0.963 to 0.910. A life table response experiment (LTRE) showed that this decline in lambda was caused mostly by declines in survival of adults. If 1988-1998 demographic rates are maintained, the model predicts a 98% chance of a population of fewer than 25 pairs within 78 years. For this population to recover to a status under which it could be "delisted," a 10% increase in survival of all age classes would be needed.
模拟建模被用于重建黑眉信天翁（Diomedea melanophris）的种群趋势。通过逐年改变生存率、繁殖成功率以及在前一年成功繁殖后返回繁殖地的概率，实现了与观测数据的紧密近似。年度数值的时间变化与南乔治亚岛延绳钓渔业的开始以及磷虾丰度的潜在变化相吻合。我们使用了来自南乔治亚岛鸟岛该物种一个繁殖群体长期研究的23年人口统计数据来验证我们的模型。当我们使用年度参数估计值来表示生存率、繁殖成功率以及在前一年成功繁殖后返回繁殖地的概率时，我们的模型轨迹紧密跟随了观测到的繁殖种群数量随时间的变化。在大多数年份，种群增长率低于更替水平（λ < 1），并且对成年个体生存率的变化最为敏感。这支持了国际自然保护联盟（IUCN）最近将该物种的保护级别从“易危”提升至“濒危”。对1988年之前和1988年之后（繁殖区域延绳钓渔业开始之前和之后）的人口统计学比较显示，λ从0.963降至0.910。一项生命表响应实验（LTRE）表明，λ的这种下降主要是由成年个体生存率的下降导致 的。如果维持1988 - 1998年的人口统计率，该模型预测在78年内种群数量少于25对的概率为98%。为了使这个种群恢复到可以“除名”的状态，所有年龄组的生存率需要提高10%。
