The rest of the island, with the exception of the Perdido Key State Park, has been developed as a resort and residential community.
As a barrier island, Perdidio Key is subject to changes due to wave action and longshore currents, particularly from hurricanes.
Perdido Key is a 24-kilometre-long (15 mi) barrier island, narrow for most of its length, with a much wider portion in the middle.
The Perdido Key Historic District, the site of three shore batteries built between 1890 and 1945 to protect the entrance to Pensacola Bay, is at the eastern end of the island.
Perdido Key probably developed in place by aggradation of offshore shoals consisting of quartz sand that is likely reworked from Pleistocene delta and shallow marine deposits.
The easternmost part of the eastern barrier spit, adjacent to Pensacola Pass, may have been an island for much of the 19th century.
(In 2020, Hurricane Sally temporarily severed the eastern end of Perdido Key from the rest of the island).
The site of the original Fort McRee, built in 1830 on the eastern end of Perdido Key (then known as Foster's Bank), was in the channel in the middle of Pensacola Pass by 1979.
The dredging has interrupted the natural transport of sand across the inlet from Santa Rosa Island to Perdido Key, with the result that Pensacola Pass is a net sediment sink.
This has starved the eastern end of Perdido Key of sand, leading to the erosion of that part of the island.
The easternmost part of the island is receiving sand dredged from the inlet in a beach nourishment project.
In the period from 1920 until 2013, the easternmost 20 kilometres (12 mi) of the island lost an average of 0.17 metres (0.56 ft) of shoreline per year.
The earliest recorded storm to affect Perdidio Key was the September 1559 hurricane which doomed the attempted Spanish colony of Ochuse on Pensacola Bay.
[17] Perdido Key has been severely damaged by several hurricanes since the 1970s; Frederic in 1979, Erin in August 1995, Opal in October 1995, Ivan in 2004, Dennis in 2005, and Sally in 2020 damaged or destroyed foredunes and eroded beaches, causing the shoreline to retreat northward as much as 18 metres (59 ft) in each storm.
Ivan brought a 14-foot (4.3 m) storm surge to the island, damaging secondary dunes as well as washing away foredunes, and causing washovers.
Sally breached the eastern end of the island in three places, creating new inlets, all of which closed again within eight months.
[22][23] Construction began in 1831 on Fort McRee at the eastern end of the island, as part of the defenses for Pensacola Bay.
[29] A long-term survey of the Perdido Key unit of the Gulf Islands National Seashore identified 384 plant species.
Chrysopsis godfreyi (Godfrey's goldenaster) is rated "imperiled" on the NatureServe conservation status scale.
Schizachyrium maritimum (gulf bluestem) and Polygonum smallianum (largeleaf jointweed) are rated "vulnerable" on the NatureServe conservation status scale.