A view on the historic and contemporary acridid fauna (Orthoptera: Caelifera: Acrididae) of Iran-A call for conservation efforts

The decline of biodiversity, specifically of insects is one of the major topics in conservation biology. In several countries of Europe, recent studies have shown a severe decline in species number and biomass of insects. In most countries of much higher diversity, much less is known about the state of the insect fauna. In this study, we focus on the acridid grasshoppers of Iran as an indicator taxon for diversity decline in a high diversity region. We used data of two surveys to suggest a change in species number between 1963 and after 2000. In the surveys before 1963, the species diversity across multiple localities in Iran was much higher compared to more recent faunistic studies. While this data is not statistically analyzable as the sampling is not completely comparable, the trends show a clear pattern of decline, which likely reflects the reality, conforms well to individual observations of less frequent encounters in the field and matches global patterns of insect decline. However, more standardized quantitative surveys are needed to generate statistically analyzable data. Potential reasons for the observed decline are severe draughts as a result of global climate change, habitat pollution, and destruction for construction and mining and especially overgrazing. Management actions need to be urgently put into place to stop the negative trends. Future studies need to document and test if these are taxon-specific trends or universal patterns in the region.