Communities, species diversity, biomass and ecological traits of carabids in the wooded pastures

Wooded pastures are greatly shaped by pastoral and silvicultural activities. Depending on abiotic factors and the intensity of human activities, the appearance and composition of wooded pastures vary considerably. There is therefore not one type of wooded pasture, but a multitude. With their sparse tree cover, semi-woodlands are an ecotone between open area pastures and forests. Transitional habitats often have a relatively high species diversity typical of the interface between two habitats. Nevertheless, wooded pastures are sometimes considered as semi-natural habitats, as these environments are mostly forged by human activities. Intensification of these activities or abandonment is a threat to wooded pastures. The aim is therefore to gain a better understanding of the ecological similarities and differences between wooded pastures and the adjacent environments: forests and nonwooded pastures. The elements tested in the three habitats are community composition, diversity indices, biomass and ecological traits in relation to environmental variable and categories to see if wooded pasture shows certain patterns compared to the other two habitats. To this end, the family Carabidae was collected with pitfall traps in the 29 study sites. Ground beetle communities in wooded pastures largely encompass those in open pastures and forests, although some species remain absent or found only in semi-wooded areas. The diversity indices indicate that wooded pastures and open pastures have an equivalent level of diversity and have significantly higher diversity than forests. Increasing the Biodiversity
Promoting Areas leads to a greater diversity of ground beetles. Tree cover significantly influences the ecological traits of ground beetles. Areas with high tree cover favour brachyptera and wingless ground beetles, as well as hygrophilic individuals. More open areas include individuals with more developed wings and generally more xerophilic tendencies. The size and also the biomass of the carabid beetles grow with increasing tree cover and vice versa. In conclusion, wooded pastures are an important ecotone, ensuring a gradual change of habitats between open areas and forests, and where a wide range of species from both habitats are found. Diversity is higher in open and semi-wooded areas than in forests, but biomass is positively correlated with tree cover, and forests have thus a higher biomass than in more open areas. Wooded pastures are an encouraging example of human-influenced habitats that retain interesting ecological characteristics for ground beetles.