Environmental Gradients and Turnover Shape Aquatic Invertebrate Communities in High‐Andean Ecosystems of Northern Chile

ABSTRACT

The high Andean salars of northern Chile are unique ecosystems characterised by their high altitude (up to > 4000 m above sea level), high salinity and marked geographical isolation. Despite their ecological importance and increasing exposure to anthropogenic pressures such as lithium extraction, the diversity and composition of their aquatic invertebrate communities remain poorly documented. A previous regional synthesis of published invertebrate records from the lithium triangle showed considerable among‐system variation, mostly related to salinity but relied on heterogeneous sampling methods, underscoring the need for standardised field surveys. This study integrates standardised sampling across 21 salars in the Antofagasta and Atacama regions to (i) characterise community composition, (ii) compare diversity between regions and (iii) identify environmental drivers of community structure. We hypothesised that environmental gradients, particularly conductivity, would explain more variation in diversity and community structure than regional affiliation. We recorded 29 taxa; Nematoda, Harpacticoida, Chironomidae, Ephydridae, Ostracoda and Hyalella being the most frequent. Diversity metrics revealed greater α‐ and γ‐diversity in Antofagasta, probably related to lower salinity and greater habitat heterogeneity at spring‐fed sites. β‐diversity was driven mainly by turnover rather than nestedness, indicating strong spatial replacement between systems. A distance‐based linear model retained conductivity, latitude, altitude, pH and surface area as predictors of community structure, with conductivity showing the strongest effect. The absence of uniform patterns indicates that each salar or lagoon represents a distinct ecological unit; impacts of resource extraction, particularly lithium mining, should therefore be evaluated at the scale of individual systems to inform conservation and management.