Climate change impact on the geographic distribution of important tachinid parasitoids in Morocco: a species distribution modelling study

Abstract

Morocco boasts remarkable ecological, orographic, geomorphological, and climatic diversity, which divides the country into seven distinct biogeographical zones. Diptera species richness, including the family Tachinidae, is relatively high in zones such as Rif, Middle Atlas, and High Atlas, but significantly lower in Eastern Morocco and the Sahara. Given the increasing impacts of climate change on species distributions and biodiversity conservation, we employed ecological niche modelling (ENM) to assess current and future habitat suitability for four key parasitoid tachinid fly species [Cylindromyia brassicaria (Fabricius), Gonia atra Meigen, G. bimaculata Wiedemann, and Tachina fera (Linnaeus)] in Morocco. Using MaxEnt modelling with occurrence records and environmental variables, we assessed present-day distributions and projected changes by 2050 under two climate scenarios (SSP126 and SSP585). Model performance was robust across species, with average AUC values ranging from 0.867 to 0.921 and average TSS values ranging from 0.503 to 0.533 across the four tachinid species. Annual precipitation emerged as the dominant predictor for most species, while temperature variables showed species-specific importance. Currently, suitable habitats are concentrated in northern Morocco, particularly in the Atlas Mountains and Mediterranean coastal regions, with 31.8–33.7% of the study area being climatically suitable. Future projections indicate habitat contractions for all species, particularly under SSP585, with reductions ranging from 10.25% to 36.20% by 2050. The High Atlas region was identified as a potential climatic refuge, maintaining relatively high habitat suitability under both scenarios. These findings provide critical insights for long-term biological control strategies using these parasitoids under current and future climate conditions. Additionally, the results can inform effective conservation and restoration efforts for tachinid species, particularly those that are threatened or endangered.