Unraveling the non-linear associations between the international legal wildlife trade and biodiversity

Abstract

Biodiversity loss is one of the most critical challenges facing the world. International wildlife trade has led to large-scale wildlife migration, which directly impacts biodiversity. However, existing studies primarily focused on qualitative descriptions or linear quantitative characterizations of these impacts, lacking an understanding of non-linear associations. This study concentrated on international legal wildlife trade, calculating the quantity of legal wildlife trade among countries and elucidating the spatial patterns of global mammal, amphibian, bird, and fish biodiversity. Non-linear associations between legal wildlife trade and biodiversity and key countries were revealed using random forest regression models (RFR), generalized additive models (GAM), and network analysis. The results indicated that (1) Asia and North America had the most active legal wildlife trades; (2) Countries with high terrestrial biodiversity included those with large land areas such as the United States, Brazil, and China, while high fish biodiversity was found in coastal nations; (3) For mammals and amphibians, the sensitivity of biodiversity to total imported type was the highest, at 0.29 and 0.34, respectively, whereas for fish and birds, the sensitivity of biodiversity to total imported quantity was the highest, at 0.36 and 0.23, respectively; (4) Biodiversity increased with the quantity/type of trade imports, showing a clear non-linear association, and countries like United States, China and Germany played a significant role in the associations between wildlife trade network and biodiversity. This study provided crucial support for future global wildlife conservation and trade policy decisions.