Rio Simpson

Río Simpson National Reserve covers 40,452 hectares in Chile's Aysén Region, running along the valley of the Río Simpson between the regional capital Coyhaique and the coast at Puerto Aysén. ^[1] Established in 1967, it is one of the oldest protected areas in Aysén Region. The reserve protects the temperate forests, wetlands, and river habitats along the Simpson Valley, which was one of the first areas settled by Chilean ranchers entering Aysén in the early twentieth century. The reserve functions simultaneously as a biodiversity conservation area, a water catchment for Coyhaique, and a recreation space for the region's population. The Carretera Austral passes through the reserve, making it highly accessible.

The reserve's temperate forest and river habitats support diverse wildlife. Pumas are present as apex predators, hunting the dense forest. Pudú — South America's smallest deer — inhabit bamboo thickets along the forest floor. Huemul, the endangered South Andean deer, are occasionally recorded in the Área de Protección Río Claro sector, accessible 16 km from Coyhaique. ^[1] South American river otters inhabit the Simpson River and its tributaries. Kodkod wildcats and Andean foxes are present. The reserve's rivers and wetlands attract numerous waterfowl, including black-necked swans and Torrent ducks. Magellanic woodpeckers, one of the world's largest woodpeckers, excavate nesting cavities in old-growth tree trunks. Condors are regularly seen overhead.

The reserve contains excellent examples of Valdivian temperate rainforest, in its somewhat drier northern Aysén expression. Dominant trees include coigüe (Nothofagus dombeyi), lenga (Nothofagus pumilio), and ñire (Nothofagus antarctica). The forest floor is rich in ferns, mosses, and bamboo (quila). Riparian vegetation along the Simpson River includes native willows and other moisture-adapted species. Higher slopes transition to subalpine meadows with cushion plants. The reserve's forests were partially logged during the early settlement era; recovery is ongoing. Introduced plants, particularly Lupinus polyphyllus, are invasive along roadsides but native vegetation is largely intact in the interior.

The Simpson Valley occupies a glacially-carved trough within the Patagonian Andes. The surrounding mountains consist primarily of Mesozoic granitic rocks (the North Patagonian Batholith) overlain by Cenozoic volcanic deposits, with peaks exceeding 1,600 m. ^[1] Moraines, outwash plains, and glacial lake sediments fill the valley floor. The Río Simpson is a vigorous glacial-fed river that drains westward to the fjords. Rocky outcrops along the valley walls display spectacular examples of glacial striation and polish. The river's turquoise color reflects glacial rock flour in suspension. Landslides are periodic along the steep valley walls, particularly following earthquakes or heavy rainfall events.

The Río Simpson valley near Coyhaique has a somewhat drier climate than other parts of Aysén due to its position in the rain shadow east of the main Andes divide. Coyhaique receives approximately 1,500 mm of annual rainfall, compared to 4,000+ mm on the Pacific-facing slopes. Temperatures are cold — annual average around 8°C — with winter minima below -10°C and summer maxima rarely exceeding 20°C. Snow falls regularly from June through September. The valley is prone to strong katabatic winds descending from the Andes, particularly in autumn and spring. The best visiting time is November through March for mild temperatures and maximum daylight.

The Simpson Valley was among the first areas colonized by Chilean settlers entering Aysén Region via Argentine routes in the early 1900s. Pioneers cleared forest for cattle grazing, establishing the ranching culture that remains central to Aysén identity. The town of Coyhaique was founded in 1929. Indigenous people — primarily Aónikenk (Tehuelche) from the steppe to the east — occasionally used the valley but were not permanent inhabitants. The valley has been a key transportation corridor; the Carretera Austral later incorporated this route, transforming the valley into a main artery for the region.

Río Simpson National Reserve was established in 1967, making it one of Aysén's first protected areas. ^[1] Its early designation reflected the importance of the valley's forests as a water catchment and the need to protect remaining native vegetation near the regional capital following destructive fires during Aysén's colonization era. ^[2] The reserve is named after Chilean naval commander Enrique Simpson, who explored the Aysén coast from 1870 to 1872. The El Claro visitor center, situated near a series of small waterfalls, has become a popular attraction for regional tourism. The reserve has been used as a field study area by researchers at the Universidad Austral de Chile and other institutions.

The El Claro sector near the reserve entrance features a series of cascades and a visitor center with interpretive displays on the Aysén ecosystem. Hiking trails traverse native lenga and coigüe forest with excellent views up and down the Simpson Valley. The Río Simpson offers fly fishing for both native species and introduced brown and rainbow trout, drawing sport fishers from across Chile and internationally. ^[1] Birdwatching along the river margins is productive, particularly for Torrent ducks. The scenic Carretera Austral highway running through the reserve provides excellent wildlife viewing opportunities.

The reserve is immediately accessible from Coyhaique, approximately 37 km along the Carretera Austral toward Puerto Aysén. ^[1] Coyhaique is the regional capital with an airport (Aeropuerto Teniente Vidal) serving Santiago. CONAF operates the El Claro visitor center with parking, restrooms, and interpretive trails near the main access point. Basic picnic and rest facilities are available at several points. The reserve is open year-round. Coyhaique has a full range of accommodation and services. The reserve is often visited as a warm-up to longer Aysén adventures along the Carretera Austral.

Río Simpson faces ongoing challenges from its dual role as a conservation reserve and a transportation corridor. Road traffic on the Carretera Austral creates vehicle strikes for wildlife and facilitates invasion by roadside exotic plants. Historical logging and fires during the early colonization era left a mixed-age forest that is gradually recovering native old-growth characteristics. ^[1] Introduced rainbow and brown trout in the river system displace and predate native fish species. The reserve's watershed function for Coyhaique's water supply creates an incentive for conservation. CONAF works with the municipality on fire prevention, given that wildfire near the regional capital would have major public safety implications.