Climate forcing and density dependence in a mountain ungulate population
Climate forcing and density dependence in a mountain ungulate population
复制标题
DOI：
10.1890/02-0753
复制
发表时间：
2004-06-01
期刊：
影响因子：
4.8
通讯作者：
Festa-Bianchet, M
中科院分区：
文献类型：
--
作者：
Jacobson, AR;Provenzale, A;Festa-Bianchet, M
生态学中的种群模型很少通过将其预测与种群规模变化的长期观察进行比较来验证。我们已经使用了各种分析工具，以研究45年的时间序列的年度人口普查的阿尔卑斯山北山羊（山羊）在大天堂国家公园在意大利西北部。在20世纪80年代，在十年的温暖冬季里，这只野山羊的数量从大约3300只增加到近5000只，然后在20世纪90年代开始下降。到1997年，人口规模已恢复到以前的水平。在种群密度增加的过程中，成虫存活率明显增加，成虫性比可能发生变化，略微有利于雄性。在有气候数据的39年中，总人口的年度变化与季节平均积雪深度和人口密度相关。结果表明，北山羊种群规模受密度依赖和积雪深度的限制。一个基于这些因素的模型适合于前19年的数据，用于预测随后的变化，总人口的基础上，初始人口规模和每年的积雪深度。该模型能够预测在研究的最后20年中总人口规模的增加和随后的下降，但未能重现火山爆发后的人口水平。我们的研究结果表明，20世纪80年代的人口增长主要是由成年人生存率的提高，而不是增加招聘。
Population models in ecology are rarely validated by comparing their predictions to long-term observations of changes in population size. We have used a variety of analytical tools to examine a 45-year time series of annual censuses of Alpine ibex (Capra ibex) in the Gran Paradiso National Park in northwestern Italy. This ibex population grew from about 3300 to almost 5000 individuals in the 1980s during a decade of anomalously mild winters, and then began to decline in the 1990s. By 1997, the population size had returned to previous levels. Adult survival apparently increased and adult sex ratio may have changed to slightly favor males during the increase in population density. Yearly changes in total population were correlated with seasonal average snow depth and population density over the 39 years for which climate data were available. Our results show that the ibex population size was limited by both density dependence and deep snow. A model based on these factors fit to the first 19 years of data was used to forecast subsequent changes in total population based on initial population size and yearly snow depth. The model was able to predict the increase and subsequent decline in total population size over the final 20 years of the study but failed to reproduce population levels after the eruption. Our results suggest that the 1980s episode of population growth was primarily driven by increased adult survival, rather than increased recruitment.