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

When freshwater inflows into estuaries are reduced, a variety of detrimental ecological outcomes can occur, underpinning the selection of "All of the above" as the correct answer.

Firstly, reduced freshwater inflow can lead to increased salinity levels within estuaries. Freshwater serves to dilute saltwater in these environments; consequently, when the freshwater supply diminishes, saltwater can intrude further into the estuary. This saltwater intrusion disrupts the existing salinity balance, which is critical for both flora and fauna that are adapted to specific salinity levels.

The changes insalinity can create favorable conditions for exotic species of plants and invertebrates, which often have different ecological requirements and can thrive in altered environments. These invasive species may outcompete native species for resources, further destabilizing the ecosystem.

Moreover, the shift in salinity levels can adversely affect populations of native species that are not adapted to higher salinity conditions. As these native species decline or are eliminated from the ecosystem, it can lead to a reduction in biodiversity, which is crucial for the resilience of the estuary.

Given these interconnected impacts—saltwater intrusion, the potential invasion of exotic species, and the decline of native populations—it is clear why the selection