Abstract <p>An overview of caddisfly fauna from the Chapada Diamantina Complex (CDC) is provided, focusing on species richness, distribution patterns, environmental gradients, and identifying priority areas/taxa for conservation. The Trichoptera fauna in the CDC includes 12 families, 28 genera, and 78 valid species, representing a 50% increase. Estimates suggest that about 50% of species remain undescribed. Biodiversity Knowledge Shortfalls (BKS) persist: 55% of species are known from a single record, and 92% have fewer than five records. 70% are known only from males, 25% have females described, and approximately 10% immature stages. Our findings highlight conservation concerns due to the Hutchinsonian deficit, as the environmental limits of species are poorly understood. The CDC’s caddisfly fauna spans broad environmental gradients, but 83% of species have narrow gradients, making them vulnerable to habitat changes. Projected climate change poses severe threats to both endemic and some widespread species, potentially leading to local extinctions. We emphasize the importance of a multidimensional approach to understanding CDC species’ tolerance to environmental changes and resilience to climate change. The need for multidimensional research on the environmental tolerances and resilience of CDC species to climate change is emphasized. Conservation strategies should focus on mitigating climate impacts and preserving biodiversity and ecosystem services.</p> Implications for insect conservation <p>This study is an initial step toward understanding the abiotic limits and distribution patterns of Trichoptera species in the CDC, an ecoregion with unique and critically endangered fauna within the Caatinga domain. We identify priority research areas, highlight species vulnerable to climate change, and emphasize the CDC’s rich biodiversity, with many undescribed taxa. Research in under-sampled areas and addressing BKS are crucial for delineating abiotic limits and identifying threats.</p>