## 1 Introduction  
Managed and unmanaged grasslands provide a variety of ecosystem services [1; 2], including provisioning services (forage production), regulating services (water and soil erosion control, agricultural pest control, soil preservation, climate stability, regulation of disease-carrying organisms, fresh water supply, flood mitigation, night cooling, and carbon sequestration), supporting services (cycling and movement of nutrients), and cultural services (aesthetic beauty). With respect to insect ecology and observed insect decline [3; 4; 5], grasslands are vital for providing forage for herbivores and pollinators (e.g., seeds, nectar,pollen, leaves, stems, and roots), supporting habitats for insect development, and maintaining biodiversity in general. For example, in semi-natural grasslands, 25 wild plant species per 100 cm\({}^{2}\) can be found with an associated rich invertebrate fauna community [6]. Insect ecology and grassland management are inextricably linked. Insects are pollinators, predators, decomposers, and food sources for other animals. They also help to regulate soil and water quality. Agriculturally oriented grasslands are usually of reduced quality with respect to wild plant species depending on the intensity of fertilizing, plowing, re-seeding, cutting, and controlling weeds. In some cases, the original wild-plant communities have been replaced by sown monocultures of cultivated varieties of grasses and clovers such as perennial ryegrass and white clover (wikipedia.org, accessed on 15 June 2023). Trends toward intensification can be a result of changes in farming types, for example, from dairy pasture to silage production for livestock fodder or for biomass generation for biogas plants. Local changes in grassland management can lead to reduced grassland diversity at a landscape scale, negatively affecting regional insect diversity, abundance, and biomass. Statistics on agricultural practices at a national (e.g., www.destatis.de, www.mass.usda.gov) or pan-national level (e.g., [[https://ec.europa.eu/eurostat](https://ec.europa.eu/eurostat)]([https://ec.europa.eu/eurostat](https://ec.europa.eu/eurostat))) can serve as a proxy for grassland intensification analysis [7; 8]. However, given the importance of grasslands to insect ecology and overall ecosystem health, improved measurement and assessment of grassland status at the regional and local scales are required. Corresponding systems for recent monitoring using remote sensing are currently under development at e.g., the European Space Agency, ([http://esa-sen4 cap.org](http://esa-sen4 cap.org)) and the National Ecological Observatory Network ([[https://www.neonscience.org/](https://www.neonscience.org/)]([https://www.neonscience.org/](https://www.neonscience.org/))). A historic satellite imagery analysis provides a core technology to investigate the possible role of local grassland cultivation changes in relation to long-term insect biomass decline [5]. We propose that annualized Normalized Difference Vegetation Index (NDVI) is a suitable proxy for annual grassland vegetation biomass with the assumption that increasing annual biomass correlates with increased grassland cultivation intensity. NDVI was designed to assess rangeland quality in the western region of the US [9; 10] and has been used extensively since. Subsequent studies have utilized various remote sensing sensors (e.g., AVHRR, MODIS, Landsat, etc.) to continuously reinforce the use of NDVI for area estimations of biomass (among many other vegetative measurements) in grassland assessments [11; 12; 13; 14; 15; 16]. The primary aim of the current study was to characterize trends in grassland biomass change in areas where pronounced insect decline had been observed [5].