Habitat

Brazilian elodea grows in slow-moving freshwater environments and can be found in a wide range of depths, up to 7m. It is also a generalist in terms of temperature and nutrient requirements. Brazilian elodea grows best between 16-28C but is capable of overwintering in freezing conditions. It can survive in low CO2 and light conditions, and high phosphorous and turbidity. Brazilian elodea is susceptible to damage from high intensity heat and light. 

Life Cycle

In the US, only male Brazilian elodea plants are present, so asexual and vegetative reproduction are the feasible reproductive means. Vegetative fragmentation occurs by nodes breaking off from a plant and either rooting or growing in free-floating form. This can occur year-round, but Brazilian elodea growth is very slow when temperatures are below 15C, so most prolific reproductive growth occurs when temperatures are above this threshold. The plant can flower biannually, in the spring and again in the fall. The flowers are insect pollinated, and seeds are dispersed and germinate when temperatures rise above 15C. Individual flowers are present for up to two days. Life cycle is dependent on year-to-year temperature trends. The 15C threshold for growth is the most influential factor in determining life cycle. Below the threshold, the plant goes dormant, and above it, growth is rapid.

Ecological Threat

Brazilian elodea can form dense stands that impact water flow and change nutrient composition and turbidity levels where it is present. It utilizes C4 photosynthesis, so is able to survive in relatively low CO2 levels, helping to outcompete native vegetation. This lowers biodiversity and removes habitat for aquatic animals and insects. Additionally, in severe infestations Brazilian elodea has been known to clog aquatic infrastructure and impact recreational activities.