Esteros

Esteros is the plural form of estero, a term used in Spanish-speaking regions to describe a range of wetland and watercourse features. The exact meaning varies by country. In inland areas, especially in Argentina and Chile, estero often denotes a small, slow-flowing river or seasonal stream. In coastal and delta regions, estero commonly refers to a tidal estuary or marsh where freshwater mixes with seawater.

Ecology and characteristics typical of esteroses include shallow waters, substrates such as mud and sand, and vegetation adapted to brackish or variable salinity. They support diverse plant and animal communities, including waterfowl, wading birds, fish, crustaceans, and amphibians. Esteros frequently function as important nurseries for fish and other aquatic life and provide ecological services such as flood regulation, sediment trapping, water purification, and carbon storage.

Human use and pressures vary by location but often include fishing, hunting, grazing, and increasingly ecotourism. Esteros are vulnerable to drainage, land conversion for agriculture, pollution, and water extraction, which can alter hydrology and biodiversity. Many esteroses are protected within national parks, reserves, or wetlands networks, reflecting their conservation value.

Notable examples include the Esteros del Iberá in Argentina, one of the region’s largest freshwater wetland systems known for high biodiversity and birdlife. In coastal Chile and other areas, estero networks are integral components of local wetlands landscapes, contributing to regional ecological function and cultural practices.