Beissinger Steven R, Peery M Zachariah
Department of Environmental Science, Policy and Management, 137 Mulford Hall, University of California, Berkeley, California 94720-3114, USA.
Ecology. 2007 Feb;88(2):296-305. doi: 10.1890/06-0869.
Reducing extinction risk for threatened species requires determining which demographic parameters are depressed and causing population declines. Museum collections may constitute a unique, underutilized resource for measuring demographic changes over long time periods using age-ratio analysis. We reconstruct the historic demography of a U.S. federally endangered seabird, the Marbled Murrelet (Brachyramphus marmoratus), from specimens collected approximately 100 years ago for comparison with predictions from comparative analyses and with results from contemporary field studies using both age-ratio analysis and conventional demographic estimators. Reproduction in the late 1800s and early 1900s matched predictions from comparative analysis, but was 8-9 times greater than contemporary estimates, whereas adult survival was unchanged. Historic reproductive rates would support stable populations, but contemporary levels should result in population declines. Contemporary demographic estimates derived from age-ratio analysis were similar to estimates from conventional estimators. Using museum specimens to reconstruct historic demography provides a unique approach to identify causes of decline and to set demographic benchmarks for recovery of endangered species that meet most assumptions of age-ratio analysis.
降低濒危物种的灭绝风险需要确定哪些种群统计学参数受到抑制并导致种群数量下降。博物馆藏品可能构成一种独特的、未得到充分利用的资源，可用于通过年龄比分析来衡量长时间内的种群统计学变化。我们从大约100年前收集的标本中重建了美国联邦濒危海鸟——斑海雀（Brachyramphus marmoratus）的历史种群统计学，以便与比较分析的预测结果以及当代实地研究使用年龄比分析和传统种群统计学估计方法得出的结果进行比较。19世纪末和20世纪初的繁殖情况与比较分析的预测相符，但比当代估计值高8至9倍，而成体存活率没有变化。历史繁殖率本可支持种群稳定，但当代水平应会导致种群数量下降。从年龄比分析得出的当代种群统计学估计值与传统估计方法的估计值相似。利用博物馆标本重建历史种群统计学提供了一种独特的方法，可用于确定种群数量下降的原因，并为符合年龄比分析大多数假设的濒危物种恢复设定种群统计学基准。
