城市化对两栖类繁殖生活史特征的影响-以上海为例

Amphibians are the most vulnerable vertebrates in the world, urbanization is considered as a major cause of the decline in their species diversity. Studies of amphibian urban ecology have been carried out on several levels, but the responses of amphibian reproductive life-history traits to urbanization remain unclear. Given the rapid urbanization underway in many areas of China, this project is going to examine reproductive traits in three species of amphibian (Bufo gargarizans, Pelophylax plancyi, and P. nigromaculata) along the urbanization gradient in Shanghai. The traits will be examined included differences in sexual dimorphism and its relationship with age structure of amphibian population, based on morphological measurements of amphibian samples combined with skeletochronology techniques. In addition, amphibian acoustic data will be collected and combined with linguistics methods to investigate patterns in amphibian mating calls along the urbanization gradient and any correlation with urban ecological factors and amphibian population characteristic. Finally, differences in amphibian reproductive strategies along the urbanization gradient during spawning and hatching will be analyzed based on field sampling and laboratory experiments. The results of this study could provide the new evidence of urbanization driving amphibian reproductive adaptation, and help us to understand further the mechanism involved in the adaptation of amphibian reproductive life-history traits to increasing levels of urbanization, as well as forming a basis for the development of amphibian conservation strategies in urban environments.

两栖类是全世界受胁迫率最高的脊椎动物，城市化被认为是造成两栖类物种多样性丧失的重要原因。两栖类城市生态学研究已在多个层面上展开，但两栖类繁殖生活史特征对城市化的响应尚不清楚。本项目拟以我国急速城市化发展典型上海市为研究平台，以上海市三种两栖类（中华蟾蜍、金线侧褶蛙、黑斑侧褶蛙）为研究对象，基于两栖类样本形态学测量并结合骨骼学技术，分析城市化梯度上两栖类两性异形强度差异及其与种群年龄结构的关系；基于两栖类声学数据采集并结合语言学技术，分析城市化梯度上两栖类求偶鸣声特征差异及其与城市化生态因子、种群特征因子的关系；通过两栖类野外采样与室内培养，探究城市化梯度上两栖类在产卵与孵化过程中的繁殖策略差异。以期为城市化驱动两栖类繁殖适应提供证据，并揭示两栖类在繁殖生活史特征方面响应城市化进程的原理，为今后制定城市化环境中两栖类保护措施提供科学依据。

城市化引起的两栖类物种多样性丧失已成为重要的全球性生物多样性保育问题，理解城市化背景下两栖类的繁殖生活史响应对预测其种群动态有重大意义。本项目以我国急速城市化发展的典型上海市为研究平台，以上海市泽陆蛙、金线侧褶蛙和饰纹姬蛙三种两栖类为研究对象，结合野外采样与室内分析手段，利用形态学、骨骼学、语言学等技术探求上海市城市化过程对两栖类两性异形强度、年龄结构、广告鸣声特征、产卵策略等繁殖生活特征的影响。本项目于2020-2022年在上海市城市化梯度上（市区-近郊-远郊区域）选取45个研究样点开展野外调查与室内实验，并基于各研究样点的不透水表面占比（建筑与道路占比之和）定义城市化指数。研究结果显示：（1）在形态特征方面，雄性与雌性金线侧褶蛙的体长与城市化指数呈显著正相关，雄性泽陆蛙的体长、头宽和后肢长，以及雌性泽陆蛙的体重和后肢长与城市化指数呈显著正相关；在年龄结构方面，远郊区域的泽陆蛙平均年龄显著高于市区区域，低龄金线侧褶蛙和泽陆蛙在市区区域有着更长的体长；在两性异形方面，市区区域泽陆蛙体长的两性异形强度显著高于近郊与远郊区域。（2）在繁殖鸣叫行为方面，饰纹姬蛙的警戒距离与城市化指数呈显著负相关；在繁殖鸣声特征方面，饰纹姬蛙的主频与泽陆蛙的脉冲率与城市化指数呈显著负相关，受城市化过程影响的生物（如两栖类合唱大小）和非生物因素（如人为噪音、空气温度、空气湿度）都对这两种蛙类的广告鸣声特征产生重要影响，但两种蛙类个体形态指标的改变不是引起广告鸣声特征改变的主要因素。（3）在产卵特征方面，近郊区域饰纹姬蛙个体相比于远郊区域个体有着更长的卵径。本项目表明城市化这一典型人类活动会驱动两栖类繁殖生活史特征发生改变，且不同两栖类物种对城市化存在响应差异，进而可能影响到其在城市环境中的种群持续。

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