Department of Biology and Program in Environmental Studies and Sciences, Rhodes College, Memphis, TN, USA.
Department of Biological Sciences, Chicago State University, Chicago, IL, USA.
Sci Rep. 2021 Feb 4;11(1):2111. doi: 10.1038/s41598-021-81073-2.
Species that live in degraded habitats often show signs of physiological stress. Glucocorticoid hormones (e.g., corticosterone and cortisol) are often assessed as a proxy of the extent of physiological stress an animal has experienced. Our goal was to quantify glucocorticoids in free-ranging small mammals in fragments of Interior Atlantic Forest. We extracted glucocorticoids from fur samples of 106 small mammals (rodent genera Akodon and Oligoryzomys, and marsupial genera Gracilinanus and Marmosa) from six forest fragments (2-1200 ha) in the Reserva Natural Tapytá, Caazapá Department, Paraguay. To our knowledge, this is the first publication of corticosterone and cortisol levels for three of the four sampled genera (Akodon, Oligoryzomys, and Marmosa) in this forest system. We discovered three notable results. First, as predicted, glucocorticoid levels were higher in individuals living withing small forest fragments. Second, animals captured live using restraint trapping methods (Sherman traps) had higher glucocorticoid levels than those animals captured using kill traps (Victor traps), suggesting that hair glucocorticoid measures can reflect acute stress levels in addition to long-term glucocorticoid incorporation. These acute levels are likely due to urinary steroids diffusing into the hair shaft. This finding raises a concern about the use of certain trapping techniques in association with fur hormone analysis. Finally, as expected, we also detected genus-specific differences in glucocorticoid levels, as well as cortisol/corticosterone ratios.
生活在退化栖息地的物种通常表现出生理压力的迹象。糖皮质激素（如皮质酮和皮质醇）通常被评估为动物经历生理压力程度的指标。我们的目标是量化内部大西洋森林片段中自由生活的小型哺乳动物中的糖皮质激素。我们从巴拉圭卡扎帕省塔皮塔自然保护区的六个森林片段（2-1200 公顷）中 106 只小型哺乳动物（啮齿动物属 Akodon 和 Oligoryzomys，以及有袋动物属 Gracilinanus 和 Marmosa）的皮毛样本中提取了糖皮质激素。据我们所知，这是在该森林系统中首次公布了四个采样属（Akodon、Oligoryzomys 和 Marmosa）中三种的皮质酮和皮质醇水平。我们发现了三个值得注意的结果。首先，正如预测的那样，生活在小森林片段内的个体的糖皮质激素水平较高。其次，使用束缚诱捕法（谢尔曼陷阱）捕获的动物的糖皮质激素水平高于使用致死诱捕法（维克多陷阱）捕获的动物，这表明毛发糖皮质激素测量值除了长期糖皮质激素结合外，还可以反映急性应激水平。这些急性水平可能是由于尿类固醇扩散到毛干。这一发现引起了人们对某些诱捕技术与毛发激素分析相关使用的关注。最后，正如预期的那样，我们还检测到了属特异性的糖皮质激素水平差异，以及皮质醇/皮质酮比值差异。
