Zhang Shuping, Zhao Lidan, Zhang Xinjie, Liang Wei
College of Life and Environment Sciences, Minzu University of China, Zhongguancun south street 27, Beijing 100081, China.
Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Longkun south road 99, Haikou 571158, China.
Conserv Physiol. 2019 Dec 6;7(1):coz096. doi: 10.1093/conphys/coz096. eCollection 2019.
Climate change induced phenological mismatches between nestlings and their optimal food resources have been found to negatively influence the survival of many bird species. Discriminating which species is vulnerable to such threat is difficult only based on the diet observation, and therefore it is necessary to establish a more reliable method to predict the vulnerability of bird species. In the case of Asian short-toed lark (), we predicted such vulnerability by evaluating whether nestlings can absorb equal level of nutrients from different diets and maintain equal physiological status. We compared the diet, plasma nutrients, plasma insulin-like growth factor-1 (IGF-1), body mass and survival rate of nestlings hatched under different optimal food (grasshopper nymph) abundance conditions in two breeding seasons. Plasma glucides, amino acids, tricarboxylic acid (TCA) cycle metabolites, some fatty acids, IGF-1, body mass and survival rate of the nestlings hatched under medium or low nymph abundance conditions were significantly lower than those of nestlings hatched under high nymph abundance condition. The relative abundance of plasma amino acids, glucides, TCA cycle metabolites and fatty acids were significantly, and positively, correlated with IGF-1 levels, which, in turn, was positively correlated with nestling body mass. These results indicate that the diet with low optimal food proportion was nutritionally inferior to the diet with high optimal food proportion and inhibited the growth of nestlings. Species like Asian short-toed lark is vulnerable to the trophic threat induced by phenological mismatch because the alternative food is insufficient to satisfy the nutritional requirement of nestlings.
气候变化导致雏鸟与其最佳食物资源之间出现物候不匹配，这已被发现会对许多鸟类的生存产生负面影响。仅基于饮食观察很难区分哪些物种容易受到这种威胁，因此有必要建立一种更可靠的方法来预测鸟类物种的脆弱性。以亚洲短趾百灵为例，我们通过评估雏鸟是否能从不同饮食中吸收同等水平的营养并维持同等生理状态来预测这种脆弱性。我们比较了在两个繁殖季节中，在不同最佳食物（蝗虫若虫）丰度条件下孵化的雏鸟的饮食、血浆营养物质、血浆胰岛素样生长因子-1（IGF-1）、体重和存活率。在中等或低若虫丰度条件下孵化的雏鸟的血浆糖类、氨基酸、三羧酸（TCA）循环代谢物、一些脂肪酸、IGF-1、体重和存活率显著低于在高若虫丰度条件下孵化的雏鸟。血浆氨基酸、糖类、TCA循环代谢物和脂肪酸的相对丰度与IGF-1水平显著正相关，而IGF-1水平又与雏鸟体重正相关。这些结果表明，最佳食物比例低的饮食在营养上不如最佳食物比例高的饮食，并且抑制了雏鸟的生长。像亚洲短趾百灵这样的物种容易受到物候不匹配引起的营养威胁，因为替代食物不足以满足雏鸟的营养需求。
