Identifying the drivers of reproductive failure in threatened turtles and tortoises

海龟和海龟正面临灭绝危机，生态系统面临崩溃的危险，失去了它们的关键功能。卵子阶段的繁殖失败是许多物种种群增长的关键障碍，但人们对这种失败的驱动因素知之甚少，特别是在受威胁的野生种群中。海龟和海龟繁殖率的下降与人类活动有关，既直接通过干扰和污染的影响，也间接通过全球变暖。气温上升导致性别比例偏向女性(由于特定温度的性别决定)，但这对精子可获得性和受精率的影响尚不清楚。同样，包括人类活动在内的环境因素对受精卵孵化率的影响也没有得到很好的理解。这个项目将结合(I)筑巢尝试和孵化结果，(Ii)气候变量和(Iii)人类活动的数据，使用新的方法准确区分受精失败和未孵化的卵的早期胚胎死亡，以确定受威胁的海龟和龟类繁殖失败的关键驱动因素。该项目将包括实验室和实地工作，与外部保护伙伴组织的合作，以及基于计算机的工作，包括使用R。

Turtles and tortoises are facing an extinction crisis, and ecosystems are at risk of collapsing with the loss of their crucial functions. Reproductive failure at the egg-stage represents a key barrier to population growth for many species, but little is known about the drivers of this failure, particularly in threatened wild populations. Declining turtle and tortoise reproductive rates have been linked to human activity, both directly via the impacts of disturbance and pollution, and indirectly via global warming. Rising temperatures are causing female-biased sex ratios (due to temperature-specific sex determination), but the implications of this for sperm availability and fertilisation rates is unknown. Similarly, the influence of environmental factors, including anthropogenic activity, on hatching rates of fertilised eggs is poorly understood.Using new methods for accurately distinguishing fertilisation failure from early embryo death in unhatched eggs, this project will combine data on (i) nesting attempts and hatching outcomes, (ii) climatic variables, and (iii) human activity, across multiple populations and locations in a multi-island system, to identify the key drivers of reproductive failure in threatened turtles and tortoises. The project will involve lab and fieldwork, collaboration with external conservation partner organisations, and computer-based work including data analysis using R.