黄河上游复合污染条件下花背蟾蜍繁殖力及种群动态研究

Environment pollution is an important cause for the global amphibian decline, and fecundity is crucial for the maintenance of population size. However, the influence of combined pollution on amphibian fecundity as well as population dynamics in natural environment is unclear yet. To address this issue, Bufo raddei, a species widely distributed in the Northwest, China, is selected to explore the effect of combined pollution on amphibian fecundity as well as population dynamics in the upper Yellow River. Baiyin, an industrial city with high contamination is chose as the research plot, while Liujiaxia, a relatively unpolluted area is chose as control. Technics such as gel electrophoresis, electron microscope, skeletal bone age assessment, population dynamic analysis and the like will be used in this study. The differences on the fecundity (including gonadal hormone level, sperm quality, egg quality, gonadal structure, spawning rate, fertilization rate) and population dynamics (including population density, age distribution, sex rate, natality, mortality, survival curve) of B. raddei between the two areas will be comparatively studied. Through the above research, we will figure out whether the compound pollution in the upper Yellow River could have an effect on the fecundity of the B. raddei as well as the population dynamics or not, and show the possible impact pathways.

环境污染是导致全球两栖类种群数量下降的一个重要因素，繁殖力对种群数量的维持具有不可替代的作用。然而，在自然环境条件下，复合污染如何影响两栖类的繁殖力，又对两栖类种群动态具有怎样的效应，目前尚不清楚。本项目以西北地区广布种花背蟾蜍（Bufo raddei）为研究对象，以黄河上游污染较重的白银和相对无污染的刘家峡为研究地区，在野外实地调查、取样的基础上，采用凝胶电泳、电镜观察、骨龄检测、种群动态分析等方法，对比研究两地区不同性别、不同年龄花背蟾蜍的繁殖力及影响因素（产卵量、受精率、胚胎成活率、性激素水平、精子质量、卵细胞质量、性腺结构等），结合种群动态参数相关指标（种群密度、年龄结构及性比、出生率、死亡率、存活曲线等），探讨黄河上游复合污染对花背蟾蜍繁殖力及种群动态的影响，并确定复合污染条件繁殖力变化对种群动态的影响效应。

黄河上游复合环境污染物对该地区两栖类繁殖状况及种群动态的影响效应尚不清楚。本项目以西北地区广布种花背蟾蜍（Bufo raddei）为研究对象，以黄河上游污染较重的白银和相对无污染的刘家峡为研究地区，在野外实地调查、取样的基础上，采用多种生物学研究方法，对比两地区不同性别、不同年龄花背蟾蜍的繁殖力及其影响因素，结合种群动态参数相关指标，旨在探讨黄河上游复合污染对花背蟾蜍繁殖力及种群动态的影响，并确定复合污染条件下繁殖力变化对种群动态的影响效应。. 项目三年执行期中，项目组成员在白银样地和刘家峡样地主要开展了以下研究工作：①花背蟾蜍栖息地水体、底泥及花背蟾蜍体内重金属污染物类型及浓度分析；②花背蟾蜍性激素水平、第二性征发育状况分析；③花背蟾蜍精子活力、产卵量及繁殖投入等繁殖力指标检测；④花背蟾蜍种群年龄结构及种群动态分析。. 研究结果显示了白银地区主要环境污染物在水体、底泥及花背蟾蜍体内的分布及累积效应，揭示了环境重金属复合污染物通过影响性激素、第二性征及个体繁殖力、繁殖投入等指标对花背蟾蜍种群动态的影响效应，结果可为两栖类物种保护及动态监测提高科学依据。