Institute of Zoology, Zoological Society of London, Regent's Park, London, UK.
Conserv Biol. 2010 Jun;24(3):778-87. doi: 10.1111/j.1523-1739.2009.01395.x. Epub 2010 Jan 7.
Local ecological knowledge can provide a unique source of data for conservation, especially in efforts to investigate the status of rare or possibly extinct species, but it is unlikely to remain constant over time. Loss of perspective about past ecological conditions caused by lack of communication between generations may create "shifting baseline syndrome," in which younger generations are less aware of local species diversity or abundance in the recent past. This phenomenon has been widely discussed, but has rarely been examined quantitatively. We present new evidence of shifting baselines in local perception of regional species declines and on the duration of "community memory" of extinct species on the basis of extensive interviews with fishers in communities across the middle-lower Yangtze basin. Many Yangtze species have experienced major declines in recent decades, and the Yangtze River dolphin or baiji (Lipotes vexillifer) and Yangtze paddlefish (Psephurus gladius) may have become extinct during the 21(st) century. Although informants across all age classes were strongly aware of the Yangtze ecosystem's escalating resource depletion and environmental degradation, older informants were more likely to recognize declines in two commercially important fish species, Reeves' shad (Tenualosa reevesii) and Yangtze pufferfish (Takifugu fasciatus), and to have encountered baiji and paddlefish in the past. Age was also a strong predictor of whether informants had even heard of baiji or paddlefish, with younger informants being substantially less likely to recognize either species. A marked decrease in local knowledge about the Yangtze freshwater megafauna matched the time of major population declines of these species from the 1970s onwards, and paddlefish were already unknown to over 70% of all informants below the age of 40 and to those who first started fishing after 1995. This rapid rate of cultural baseline shift suggests that once even megafaunal species cease to be encountered on a fairly regular basis, they are rapidly forgotten by local communities.
当地生态知识可为保护提供独特的数据来源，特别是在调查稀有或可能灭绝物种的现状方面，但它不太可能随时间保持不变。由于代际之间缺乏沟通，对过去生态条件的看法可能会丧失，从而导致“基线转移综合征”，即年轻一代对当地物种多样性或近期丰度的认识降低。这种现象已经被广泛讨论，但很少被定量研究。我们根据对长江中下游流域各个社区渔民的广泛访谈，提供了有关当地对区域物种减少的认识以及对灭绝物种“社区记忆”持续时间的基线转移的新证据。近几十年来，许多长江物种经历了重大衰退，而长江豚或白鳍豚（Lipotes vexillifer）和长江白鲟（Psephurus gladius）可能已在 21 世纪灭绝。尽管所有年龄段的受访者都强烈意识到长江生态系统资源枯竭和环境恶化的情况，但年长的受访者更有可能认识到两种商业上重要的鱼类，即鲥鱼（Tenualosa reevesii）和长江鱤鱼（Takifugu fasciatus）的减少，并在过去遇到过白鳍豚和白鲟。年龄也是受访者是否听说过白鳍豚或白鲟的重要预测因素，年轻的受访者对这两种鱼类的认识明显减少。当地对长江淡水巨型动物群的知识明显减少，与这些物种从 20 世纪 70 年代以来的主要种群下降相吻合，而 70%以上的 40 岁以下受访者以及那些在 1995 年以后开始捕鱼的受访者都不认识白鲟。这种文化基线迅速转移的速度表明，一旦巨型动物物种不再经常被发现，它们就会被当地社区迅速遗忘。
