Final answer:
The most likely short-term environmental change to directly affect egrets in Florida is a drought, which reduces water levels in their wetland habitats, impacting their food supply and potentially their population.
Step-by-step explanation:
The short-term environmental change most likely to directly affect a population of egrets along the coast of Florida is drought. Drought can result in shallow water levels and decreased availability of fish and insects, which are the main food sources for egrets. This scarcity of food can lead to a decline in the egret population as individuals struggle to find enough resources to survive and reproduce.
Egrets rely on shallow waters of marshes and wetlands to find food such as fish and insects. During a drought, these water levels can drop significantly or even dry up entirely, reducing the egret's ability to find food and potentially impacting their population. Unlike earthquakes or forest fires, which are less predictable and may not directly impact egret habitats, droughts can have severe effects on wetland ecosystems over a shorter period. These effects include changes in the life cycles of prey animals and the availability of the aquatic environments that egrets depend on for survival.