Orthoptera diversity and community ecology in the mountainous pastures of two protected areas (Natura 2000) in Greece

Mountainous ecosystems are biodiversity refugia and centers of endemism. This study explores the Orthoptera communities in the Tymphi and Smolikas mountains within the Northern Pindos National Park in Greece (sites of the Natura 2000 network). We selected 11 montane pastures per mountain, including grasslands and forest clearings (1,250 to 1,940 m). We recorded the presence of Orthoptera and 20 microhabitat parameters in three 5 x 5 m plots per site every 150 m and repeated this three times (pooled seasonal data for June-September 2022: 66 plots in total). Furthermore, we randomly searched for red-listed species and recorded the microhabitat parameters in their presence (35 additional plots). The study area has high ecological value, hosting 70 grasshopper species (54 species recorded in the current study), including 10 globally red-listed species and 3 endemics. The Canonical Correspondence Analysis showed that elevation, mean herb/grass height, flowerhead abundance, stony cover, and shrub cover regulated the Orthoptera community composition (CCA: 14% of the variance explained) and that elevation, flowerhead abundance, shrub cover, and litter cover regulated the red-listed Orthoptera community (CCA: 32% of the variance explained). Orthoptera species richness was predicted by herbaceous plant cover, mean herb/grass height, mean shrub height, and flowerhead abundance (a positive effect), as well as litter cover (a negative effect) (Generalized Linear Model: 43% of the deviance explained). Our findings highlight the importance of food resources (herbaceous plant cover and herb/grass height) and shrub availability, providing shelter and thermoregulation, for grasshopper conservation. Further research is recommended to investigate the impact of cattle overgrazing and the role of mild sheep/goat grazing for mountainous Orthoptera communities. Our fieldwork was supported by the Feraki Fund.