Abstract
While invasive species obtain widespread attention for their ecological implications, the earlier stages of their invasion usually remain as uncharted territory. Procambarus clarkii is well known for being one of the most successful invaders worldwide, and yet little is known of how the population and its individuals are affected by the environment during the initial establishment. Therefore, this project has focused on investigating the role of density- and temperature- dependent factors influencing the population growth rate and somatic growth rate of P. clarkii in replicated self-sustained mesocosms. A state-space model revealed that temperature and density play a significant role in in population dynamics of the crayfish, where high temperatures and high density resulted in a large population increase during spring. Meanwhile, high competition and low resource availability in the following summer led to a population crash. Key findings from a linear mixed-effects model revealed that the significant influence of density and temperature on somatic growth rate suggested a possible ripple effect on the dynamics of population growth rate. Additionally, it was suggested that crayfish somatic growth was rescued as the crayfish grew larger, and that ecology may have a stronger effect on somatic growth than physiology. Lastly, both sex and crayfish size seamed to play a role in energy allocation, due to the hierarchical nature of P. clarkii.