Data was collected to look at long-term trends in invertebrate ground predators. This dataset consists of count data (by gender) for all species of spider collected from three habitats (mire, dwarf-shrub heath, pine woodland) at the Cairngorms Environmental Change Network (ECN) site between 2004 and 2021. Spiders were collected in pitfall traps on a two-weekly basis between March and early November. Each habitat contained ten pitfall traps, spaced 10 m apart. Samples were aggregated by habitat and collection date prior to analysis. The number of male and females of each species was recorded by the same expert araneologist for the duration (2004-2021). Full details about this dataset can be found at https://doi.org/10.5285/6077cd88-ad40-44bd-806a-fa3cebaa29d7