Carijós

Carijós Ecological Station is a federal strict-protection reserve encompassing an important mangrove complex on the island of Florianópolis, the capital of Santa Catarina state in southern Brazil. Covering approximately 759 hectares, it protects estuaries, restinga shrubland, and extensive tidal mangroves across two sectors — the Ratones and Saco Grande estuaries — in the northern part of the island. ^[1] Established by Federal Decree No. 94,656 on 20 July 1987 in response to rapid urbanisation threatening Florianópolis's coastal ecosystems, the station is managed by ICMBio and represents one of the southernmost significant mangrove systems on the Brazilian Atlantic coast. As an ecological station, it is closed to general public entry and reserved for scientific research and environmental monitoring, even as it sits directly against the urban fringe of a growing city. Carijós conserves vital nursery habitat for coastal fisheries and a rich estuarine biodiversity.

Carijós supports exceptional coastal and aquatic biodiversity, with approximately 500 animal species recorded, including around 227 bird species representing about 65% of Florianópolis's avifauna. ^[1] The mangrove channels serve as vital nursery grounds for fish species harvested commercially off the Santa Catarina coast, including snook and mullet. Neotropical otters hunt in the tidal creeks and are frequently seen near the mangrove margins, while the crab-eating raccoon and coati forage along the fringes at low tide. The estuaries and mudflats are important for waterbirds such as herons, egrets, and roseate spoonbills, which feed there year-round, and the reserve's wetlands host migratory shorebirds during the austral summer. Mangrove crabs, shrimp, and other invertebrates form the productive base of the estuarine food web that sustains this diversity. By protecting these interconnected mangrove, restinga, and open-water habitats within a heavily urbanised island, Carijós safeguards a concentration of coastal wildlife that has largely disappeared from the surrounding developed shoreline.

The station's dominant vegetation is mangrove forest, composed chiefly of red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa), and black mangrove (Avicennia germinans). ^[1] These species form dense, root-tangled intertidal forests along the sheltered estuarine channels of the Ratones and Saco Grande sectors. Restinga — coastal shrubland on sandy soils — forms transition zones between the tidal areas and terra firme, supporting bromeliads, cacti, and orchids adapted to nutrient-poor sandy conditions. Fragments of Atlantic Forest on the reserve's upland margins add further habitat diversity, while aquatic plants colonise the freshwater reaches above tidal influence. The exotic white ginger lily (Hedychium coronarium) invades disturbed margins and is a management concern. This gradient from tidal mangrove through restinga to Atlantic Forest fragments gives Carijós a diverse coastal flora within a compact area on the northern shore of Florianópolis Island.

Carijós sits on the northern coastal plain of Santa Catarina Island, where Precambrian granitic basement rocks are overlain by Quaternary sediments. Holocene marine transgression deposited the sandy barrier beaches and restinga substrates, while river-borne sediments have built the estuarine mudflats that mangroves colonise. The Ratones River drains a small catchment in the island's hilly interior and delivers fine silts and organic material to its estuary. The tidal range in the area is microtidal, generally well under a metre, which favours the development of stable, well-vegetated mangrove stands rather than the more dynamic systems found along Brazil's macrotidal northern coast. ^[1] The interplay of granitic hills, sandy Holocene plains, and sheltered estuarine embayments creates the low-energy, sediment-trapping conditions in which the station's mangroves and restinga have developed and persisted along this southern stretch of the Atlantic coast.

The Florianópolis region experiences a humid subtropical climate (Köppen Cfa), with rainfall spread through the year averaging roughly 1,500 to 1,700 millimetres and no pronounced dry season. Summers, from December to February, are hot and humid, with temperatures regularly reaching the low to mid thirties Celsius and frequent afternoon thunderstorms, while winters, from June to August, are mild but subject to cold fronts from the south that can push temperatures below ten degrees. The Santa Catarina coast is periodically affected by extratropical cyclones and frontal systems that generate storm-surge events, which influence mangrove health and shoreline stability. Sea-surface temperatures in the adjacent bay range from around 18 degrees in winter to 26 degrees in summer. This mild, moist, seasonally variable climate near the southern limit of Brazilian mangroves shapes the growth and distribution of the station's coastal vegetation.

The name Carijós refers to the Guaraní-related Indigenous group that inhabited the Santa Catarina coast before Portuguese colonisation in the sixteenth century. The Carijós fished the estuaries, harvested mangrove crabs, and maintained seasonal encampments along the bay margins. European colonisation in the seventeenth and eighteenth centuries, particularly by Azorean settlers, brought fishing villages and small-scale agriculture to the island's northern coast, and mangrove wood was historically cut for construction and charcoal. ^[1] Through the twentieth century, the rapid urban expansion of Florianópolis began encroaching on the estuaries, leading to landfilling and pollution that spurred calls for formal protection of the remaining mangrove complexes. The creation of the ecological station in 1987 was a direct response to this pressure, preserving estuarine areas that had survived largely because their tidal, waterlogged terrain resisted development.

Carijós Ecological Station was established by Federal Decree No. 94,656 on 20 July 1987, at a time when rapid urbanisation was threatening Florianópolis's coastal ecosystems. ^[1] The protected area brought together two distinct estuarine complexes — Ratones and Saco Grande — that had survived development pressure thanks to their tidal, waterlogged terrain. It is managed by ICMBio, which periodically updates the management plan to address boundary encroachment, water-quality degradation from urban runoff, and mangrove die-back. Restoration projects have replanted mangroves in areas disturbed by illegal construction and channel modification, and the station collaborates with the Federal University of Santa Catarina (UFSC) on long-term ecological monitoring. As a strict-protection unit pressed directly against a growing city, Carijós exemplifies the challenge of conserving intact coastal ecosystems within an intensely urbanised setting, and it remains a key reference site for mangrove science in southern Brazil.

Carijós does not permit general public visitation within its boundaries; the protected estuaries are accessible only to researchers and ICMBio staff holding active permits. A small visitor reception point near the Ratones River provides interpretive material and serves as a base for community environmental-education programmes. Kayak and canoe wildlife observation is practised from community-operated launch points at the reserve's edge in Ratones, allowing appreciation of the mangroves without entering the strictly protected core. Nearby beaches on Florianópolis Island, such as Jurerê, Daniela, and Canasvieiras, offer coastal access adjacent to the station's buffer zone, where mangrove birdlife is visible from public shorelines. For visitors, the surrounding island offers abundant coastal scenery and recreation, while the ecological station itself remains reserved for research and monitoring of its mangrove ecosystems.

There are no visitor facilities within the ecological station, which is closed to tourism. Florianópolis serves as the gateway, with an international airport and a full range of hotels, restaurants, and services. The Ratones community at the reserve boundary is reachable by bus from central Florianópolis in roughly 45 minutes, and the nearby northern beaches of Canasvieiras, Jurerê, and Ingleses provide accommodation and coastal recreation within a few kilometres of the protected mangroves. ^[1] Researchers requiring access to the station must apply to ICMBio's Santa Catarina office well in advance of fieldwork and obtain the necessary permits. Because the reserve sits within a major tourist destination, general visitors can easily experience the wider coastal environment of Florianópolis Island while respecting the boundaries of the strictly protected estuaries at Ratones and Saco Grande.

Carijós faces ongoing threats from urban encroachment, wastewater discharge into its estuarine channels, and illegal landfilling of mangrove margins for construction. Deforestation and urban runoff in the Ratones River catchment increase sediment and nutrient loads reaching the estuary, degrading water quality. Exotic species, particularly the white ginger lily (Hedychium coronarium), invade freshwater margins and displace native vegetation. ICMBio has partnered with Florianópolis municipal authorities on buffer-zone planning and zoning enforcement, and water-quality monitoring from the station's estuaries has informed upgrades to municipal wastewater treatment in northern Florianópolis. Sea-level rise projections indicate increased tidal flooding of low-lying restinga over coming decades. By conserving one of the southernmost significant mangrove systems on the Atlantic coast, Carijós protects critical fish nursery habitat and coastal biodiversity, underpinning both regional fisheries and the ecological resilience of an intensively developed island shoreline.