These data are related to the investigation of species traits as a guidance for moth conservation in the highly anthropogenic European region of Flanders (northern part of Belgium) based on Multi-Species Change Indices (MSCIs). Abstract Insects appear to decline rapidly in recent decades. This so-called sixth mass extinction garnered significant media attention, raising public awareness. Macro-moths—a species-rich and ecologically diverse insect group—face severe declines, particularly in urbanised and intensively farmed areas. Flanders is a highly anthropogenic region, serving as a case study where the impact on macro-moths of stressors like intensive agriculture, industrialization and urbanization has been quantified through a recently compiled Red List. Here, for 717 macro-moth species, we calculated relative changes in distribution area between a reference period (1980-2012) and the subsequent period (2013-2022). By correlating these species-specific trends with ten key ecological and life-history ... : The dataset consists of seven files. The files are described below. prop_data_per_trait_intermed.csv: gives the intermediate data with following columns: species_nl: Dutch vernacular name of the species n_grids: number of 5 x 5 km² grids in which the species was encountered period: period of 1980-2012 (p1980_2012) or 2013-2022 (p2013_2022) rel_prop: relative proportion of 5 x 5 km² grids in which the species was encountered trait_name: name of trait trait_value: value of trait linked to species prop_data_per_trait_nozero_intermed.csv: gives the intermediate data where species with zero occurrences were removed with the same columns as the previous datafile. prop_data_per_trait.csv: gives the processed data used for final analysis with additional columns compared to the intermediate datafile: species_new: adjusted names for species that have two different trait values for the same trait sum_per_period: number of 5 x 5 km² grid cells visited per period n_spec: number of species per trait value ...