高海拔和高纬度生境的相似性:综述以及青藏高原鸟类肾上腺皮质激素对应激反应的初步研究

在介绍性教科书、保护计划甚至基础著作中 ,常常将北极区和高山生物群系等同看待。高山和北极区生物群系无树的广阔区域 ,草本和非禾本科草本植物的初级生产力总量低 ,食物网单一。此外 ,除热带高山生境可能有例外 ,该两种环境都具有明显的季节性。但是 ,对于这些表面上相似的环境以前很少进行比较 ,而两者之间应具有明显的不同。我们假定 :如果环境相似 ,栖息在这些环境里的鸟类会对意外的应激刺激表现出相似的反应。相反 ,如果这些环境很不同 ,那么鸟类对剧烈应激的反应可进行调整以适应当地的不同环境 ,而不应一成不变。本文初步报道了青藏高原某些繁殖鸟类的肾上腺皮质反应 ,并与已发表的栖息于北极区苔原生态系统鸟类的数据进行了比较。白腰雪雀 (Onychostruthustaczanowskii)和棕颈雪雀 (Pyrgilaudaruficollis)被认为是高山代表物种 ,随着标准化捕捉 -处理 -抑制的应激刺激 ,它们表现出典型的血浆肾上腺皮质酮含量升高。但是 ,不同于许多北极区的代表物种 ,它们对应激的肾上腺皮质反应并无任何季节性变化。研究结果表示 :生活在高山和北极区环境下的鸟类物种可能具有激素反应以适应其生存环境所施加的生态挑战 [动物学报 49(1) :1～ 19,2 0 0 3]。

How similar are high latitude and high altitude habitats? A review and a preliminary study of the adrenocortical response to stress in birds of the Qinghai-Tibetan Plateau

Arctic and alpine biomes are frequently considered the same in introductory textbooks, conservation planning and even in the primary literature. Both alpine and arctic biomes are treeless expanses with low amounts of grass- and forb-based primary productivity, and simplified food webs. Furthermore, with the possible exception of tropical alpine habitats, both environments are highly seasonal. Few studies, however, have made a critical comparison of these superficially similar environments. They have some significant differences, including energy regimes, proximity to refugia and scale of the habitat. If the environments are the same, our hypothesis is that birds inhabiting them will exhibit similar responses to unpredictable stressors. Conversely, if these habitats are sufficiently different, then responses to acute stress should be attuned to the local environment and not be the same. A preliminary study was conducted to compare the adrenocortical responses of selected avian species breeding on the Tibetan Plateau of Central China with published data of birds inhabiting the arctic tundra ecosystem. Two species of snowfinch, Onychostruthus taczanowskii and Pyrgilauda ruficollis, are regarded as high altitude specialists and show typical increases in plasma levels of corticosterone following a standardized stress of capture, handling and restraint. However, neither showed any seasonal variation in adrenocortical response to stress, unlike many arctic specialists. This study suggests that avian species living in alpine and arctic environments may have hormonal responses tailored to the ecological challenges presented by their environment[Acta Zoologica Sinica 49(1):1-19,2003].