Thomson Robin B, Alderman Rachael L, Tuck Geoffrey N, Hobday Alistair J
Oceans and Atmospheres Flagship, CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, Tasmania, 7001, Australia.
Department of Primary Industries, Parks, Water and Environment, GPO Box 44, Hobart, Tasmania, 7001, Australia.
PLoS One. 2015 Jun 9;10(6):e0127006. doi: 10.1371/journal.pone.0127006. eCollection 2015.
The impacts of climate change on marine species are often compounded by other stressors that make direct attribution and prediction difficult. Shy albatrosses (Thalassarche cauta) breeding on Albatross Island, Tasmania, show an unusually restricted foraging range, allowing easier discrimination between the influence of non-climate stressors (fisheries bycatch) and environmental variation. Local environmental conditions (rainfall, air temperature, and sea-surface height, an indicator of upwelling) during the vulnerable chick-rearing stage, have been correlated with breeding success of shy albatrosses. We use an age-, stage- and sex-structured population model to explore potential relationships between local environmental factors and albatross breeding success while accounting for fisheries bycatch by trawl and longline fisheries. The model uses time-series of observed breeding population counts, breeding success, adult and juvenile survival rates and a bycatch mortality observation for trawl fishing to estimate fisheries catchability, environmental influence, natural mortality rate, density dependence, and productivity. Observed at-sea distributions for adult and juvenile birds were coupled with reported fishing effort to estimate vulnerability to incidental bycatch. The inclusion of rainfall, temperature and sea-surface height as explanatory variables for annual chick mortality rate was statistically significant. Global climate models predict little change in future local average rainfall, however, increases are forecast in both temperatures and upwelling, which are predicted to have detrimental and beneficial effects, respectively, on breeding success. The model shows that mitigation of at least 50% of present bycatch is required to offset losses due to future temperature changes, even if upwelling increases substantially. Our results highlight the benefits of using an integrated modeling approach, which uses available demographic as well as environmental data within a single estimation framework, to provide future predictions. Such predictions inform the development of management options in the face of climate change.
气候变化对海洋物种的影响往往因其他压力因素而更加复杂，这使得直接归因和预测变得困难。在塔斯马尼亚的信天翁岛繁殖的羞怯信天翁（Thalassarche cauta）觅食范围异常受限，这使得区分非气候压力因素（渔业兼捕）和环境变化的影响变得更容易。在脆弱的育雏阶段，当地环境条件（降雨量、气温和上升流指标海面高度）与羞怯信天翁的繁殖成功率相关。我们使用一个年龄、阶段和性别结构的种群模型，在考虑拖网和延绳钓渔业的渔业兼捕情况的同时，探索当地环境因素与信天翁繁殖成功率之间的潜在关系。该模型使用观察到的繁殖种群数量、繁殖成功率、成年和幼年存活率的时间序列以及拖网捕鱼的兼捕死亡率观察数据，来估计渔业可捕性、环境影响、自然死亡率、密度依赖性和生产力。将成年和幼年鸟类在海上的观察分布与报告的捕捞努力相结合，以估计附带兼捕的脆弱性。将降雨量、温度和海面高度作为年度雏鸟死亡率的解释变量具有统计学意义。全球气候模型预测未来当地平均降雨量变化不大，然而，预计温度和上升流都会增加，预计这将分别对繁殖成功率产生不利和有利影响。该模型表明，即使上升流大幅增加，也需要将目前至少50%的兼捕量减少，以抵消未来温度变化造成的损失。我们的结果突出了使用综合建模方法的好处，该方法在单一估计框架内使用可用的人口统计和环境数据，以提供未来预测。这些预测为面对气候变化时管理方案的制定提供了依据。
