When freshwater inflows into estuaries are reduced, what is a potential outcome?

When freshwater inflows into estuaries are reduced, several significant ecological outcomes can occur, which collectively contribute to the overall health and biodiversity of the estuary.

The intrusion of saltwater into the estuary is a primary concern. Estuaries are typically characterized by a mixture of freshwater from rivers and saltwater from the ocean. When freshwater is diminished, this can lead to increased salinity, affecting the species that thrive in these environments. Many native plants and animals are adapted to specific salinity levels and may struggle to survive in more saline conditions, leading to a decline in their populations.

The alteration in salinity also creates opportunities for exotic species to invade the estuary. These species may be more tolerant of higher salinity levels and can outcompete native species for resources, further stressing local ecosystems. This invasion can disrupt the food web and alter habitat structures, compounding the negative impacts on biodiversity.

Declining populations of native species can result from both the increased salinity and competition with invasive species. As conditions shift away from those that native species are adapted to, their numbers may dwindle, leading to decreased biodiversity and potential loss of some species entirely.

Thus, reduced freshwater inflows into estuaries lead to a cascade of effects that includes