Challenges for Quantifying Knowledge Shortfalls on Tropical Pollinators in the Face of Global Environmental Change – Brazilian Bees as a Case Study

Assessing the extent of ongoing pollinator declines and predicting future changes is key to defining priorities and developing adequate policies to mitigate the consequences of such negative trends. Nevertheless, a lack of basic information on species identity, trends, traits, and requirements hinders our ability to make such assessments. Such knowledge gaps are particularly pronounced in tropical regions, which are expected to be severely affected in the upcoming years by climate change. Identifying which taxonomic groups and regions have greater gaps can help direct efforts. Recent studies proposed groups of knowledge to quantify the extent of our ignorance (shortfalls) and proposed methods to quantify them for pollinators. Here, we use Brazilian bees as a case study to evaluate the feasibility of applying these proposed methods to tropical pollinators and provide a first assessment of the extent of these knowledge gaps. While some adaptations were proposed, we evaluated for the first time all seven shortfalls (Linnean, Wallacean, Raunkiaerian, Eltonian, Prestonian, Darwinian, and Hutchinsonian) and the Keartonian impediment. We found that the Linnean shortfall of Brazilian bees is at least five-fold the one recently found for the European countries with the most outstanding shortfalls (i.e., an increase rate of 1% species per year, reaching 3% for certain families). Also, more than half of Brazil’s land area (ca. 57.5% of the 50x50 km pixels) lacks known bee records, and most species have less than ten spatially unique known records, indicating the extent of the Wallacean shortfall. Despite these gaps, important sources of information do exist and are just not accessible or spread out. Substantial compilation efforts would be necessary to unite existing information into unique databases. Considerable collaborative efforts and incentives to make standardized data accessible and public are crucial to advance in this field and guide actions to reduce the knowledge gaps.